Autoimmunity In Psoriasis [1 ed.] 9780367235383, 9780429280283, 9781000013245, 9781000019766, 9781000006421

Table of contents :

Part 1: Concepts of Autoimmunity, Genetics, and Histology


1. Nature of Autoimmunity: Unified Concept and Other Theories as related to Psoriasis


Ernst H. Beutner


2. The Association of HLA and Psoriasis


Vera B. Morhenn and Eugene M. Farber


3. Histology of Psoriasis: the Role of Polymorphonuclear Neutrophiles


Stefania Jablonska, Olena Chowaniec, and Ewa Maciejowska


Part 2: Humoral Immune Responses in Psoriasis


4. Stratum Corneum Antigens and Antibodies as Revealed by Immune Adherence and Indirect Hemagglutination


Hans-Kristian Krogh and Olav Tonder


5. Immunofluorescence Findings on Stratum Corneum Antibodies, Antigens, and Their Reactions In Vitro and In Vivo as Related to Repair and Psoriasis


Ernst H. Beutner et al.


6. Immunofluorescence Studies on Stratum Corneum Antibodies


Walter L. Binder, Ernst H. Beutner, and Stefania Jablonska


7. IF Studies of Psoriatic Scales and Induced Psoriatic Lesions (Koebner Phenomenon)


Stefania Jablonska et al.


8. Chemotactic Factors in Psoriatic Scales


Hachiro Tagami and Shigeo Ofuji


9. Role of Polymorphonuclear Leukocyte Chemotaxis in Psoriasis


Enno Christopher, Jens-M. Schenker, and Andrzej Langner


10. Immunoglobulins and Rheumatoid factors in Psoriasis


Jean-Jacques Guilhou Clot, and Jean Meynadier


11. Immunopathologic Studies of the Joints in Psoriatic Arthritis


Ole Fyrand et al.


12. Stratum Corneum Antigens as related to Bacteria and Sweat


W. Clark Lambert and Ernst Beutner


Part 3: Cellular Responses in Psoriasis and Hypotheses on Their Role


13. Immunoinflammatory Phenomena in Psoriasis


Otto Brain-Falco and Reiner Scherer


14. Mononuclear Cell Function and its Relative Potential in the Pathogenesis of Psoriasis


Gerald Krueger and Warren W. Jederberg


15. Cellular factors in Psoriasis and Their Interaction with Humoral factors


Wieslaw Glinski


16. remission of Psoriasis During Peritoneal Dialysis. A Possible Role of Polymorphonuclear Leucocytes (PMNL) and Their Neutral Serine Proteinases in the Pathogenesis of the Disease


Wieslaw Glinski and Stefania Jablonska


17. Neutrophil Function in Psoriasis: Increased Adherence and Enhanced Superoxide Generation


Paul R. Bergstresser, Julie B. Sedgwick, and Eric R. Hurd


18. Studies on Cellular Aspects of the Immune Response in Psoriasis


Jacques Clot and Jean-Jacques Guilhou


19. Hypothetical Role of Immunological Factors in Psoriasis


Jean-Jacques Guilhou, Jacques Clot, and Jean Meynadier


Part 4: Methods for Studies of Immnune and Cellular Responses in Psoriasis


20. Immune Adherence and Indirect Hemagglutination Tests for Detection of Stratum Corneum Antibodies


Hans-Kristian Krogh and Olav Tonder


21. Methods for Immunofluorescence Studies of Stratum Corneum Antibodies


Ernst H. Beutner,. Walter L. Binder, and Vijay Kumar


22. Methods for Chemotaxis Studies of Psoriatic Scales


Hachiro Tagami and Shigeo Ofuji


23. Hemadsorption Techniques for the In Situ Characterization of Monoclear Cells in Tissue


Olav Tonder and Hans-Kristian Krogh

Citation preview

Autoimmunity •

Ill

Psoriasis Editor

Ernst H. Beutner, Ph.D. Professor of Microbiology and Clinical Professor of Dermatology Schools of Medicine and Dentistry State University of New York at Buffalo Buffalo, New York and Director of IF Testing Service Kenmore, New York

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FOREW ORD Recent years have witnessed the beginning of an era of enlightenment for us who have struggled through the “ dark ages” of coping with psoriasis, trying to bring comfort and relief to beleaguered patients without understanding the essential nature of the disease. We still have many fundamental questions to ponder, but much more hopefully now because of leads opened by immunologic researches, many of them carried out by contributors to this volume. The pages that follow detail much of this work and its interpretations, including thoughts about the ubiquitous autoantibodies against the horny layer of the skin, some reactive with plaque in the patient, some forming immune complexes, and some perhaps acting as blocking antibodies, probably depending upon molecular class. It will be surprising in the long run if certain of these do not prove to be related to the evolution of the disease, and, perhaps, to its origin. Similar reasoning suggests the possibility that reactive lymphocytes will be found to play a role in basic aspects of psoriasis, perhaps with an interplay of these cells and antibodies in the evolution of lesions. The newer intrusion into the picture of the major histocompatibility complex — and its associated genes that govern immune responses and “ immune antigens” (la) — has added a great stimulus to the quest for immunologic answers to important questions about the disease. Eugene M. Färber, M.D. Stanford University Stanford, California

FOREW ORD Psoriasis is one of the key problems in Dermatology. About 1 to 2°7o of the European population suffers from this disease, a disease of the healthy persons, which however, can disturb severely the psychological and social behavior of the patient. In the last years, however, new therapeutic measurements have come up with phototherapy, photochemotherapy and new developments of drugs such as aromatic dérivâtes of retinoids, which give hope that in the near future it will be possible to treat our psoriatic patients successfully with clean and nontoxic regimens. What, however, is the cause of psoriasis? There is probably no other skin disease on which so many dermatologists and researchers from other fields of medicine and natural sciences have done so many investigations, to elucidate the secrets of the psoriatic skin reaction. What are the main results of this work of the last 20 years? We know that psoriasis has a genetic basis which might be connected with the HLA system on the chromosome 6. We know the endogenous of exogenous provocation induces phenotypic clinical psoriasis on the basis of a given genotypic psoriasiaions, we know that increased epidermopoesis, disturbances in keratinization and cellular as well as exudative inflammatory phenomena are the main alterations in psoriatic skin lesions. However, we do not know whether psoriasis is primarily an epidermal or dermal disease — or a disease on the basis of a genetically determined alteration in regulatory systems of the epidermal or dermal tissue. Therefore, also the new and extremely interesting immunologic aspects of this disease should be brought to our knowledge. Are immunological reactions of primary importance in the pathogenesis or psoriasis or are they only secondary phenomena which are of importance in the self-perpetuation of psoriatic lesions? Ernst Beutner has induced international cooperation to collect all information about immunology of psoriasis. We should be grateful to him for his enthusiasm and activity to gain a better insight into this very difficult and controversial field of psoriatic pathogenesis. Otto Braun-Falco, M.D. University of Munich Munich, West Germany

INTRODUCTION This book affords a fresh outlook on the nature of psoriasis. Dermatologists and dermatopathologists have long recognized that acanthosis together with hyperkeratosis and papillomatosis are characteristic features not only of psoriasis but also of many other skin diseases. Yet psoriasis is a distinctive disease. It is not surprising, therefore, that increasing numbers of specialists in psoriasis now question the validity of implicating loss of control of epidermopoesis as the most basic defect in the disease. This book lends support to the growing skepticism about the putative primary role of hyperproliferative responses in the induction of typical lesions and focuses attention on the role of leukocytes and immune responses in psoriasis. Specifically, of great interest are the findings that minute papules which precede the appearance of typical psoriatic lesions have little or no hyperkeratosis, acanthosis, or papillomatosis. They do, however, have marked leukocytic infiltrates as described in this book by Jabtonska and her associates. Futhermore the first changes seen in the transition of these papules into typical psoriatic lesions usually take the form of the conversion from an acute type inflammatory infiltrate to the chronic type of the fully developed lesions. In the transitional lesion hyperakeratosis with signs of immunologic reactions appears characteristically. Usually the last of the changes to appear in the development of the characteristic psoriatic lesions is the development of acanthosis and papillomatosis. These important new findings together with the well-known isomorphic or Koebner reaction and the now well-established genetic predisposition to psoriasis lend support to the basic thesis of this book, notably the role of autoimmunity in the induction and perpetuation of lesion formation. The first of the immunologic findings in psoriasis to receive wide acceptance centers on the role of in vivo reactions of the universal stratum corneum antibodies in the development of the so-called “ squirting papillae” of Pinkus and the resultant formation of Munro microabscesses. The demonstration by Tagami and Ofuji of complement derived chemotaxins in psoriatic scales as well as the diverse studies on stratum corneum autoantibodies set forth in this book leave little doubt that immunologic mechanisms underlie the development of these characteristic features of the disease. These findings in turn provide a strong impetus to further studies in this area of research. If we view in perspective the findings on the role of stratum corneum autoantibody reactions in the formation of the characteristic Munro microabscesses and development of the less common but sometimes fatal pustular psoriasis, they give rise to a rather basic question on the nature of autoimmunity. Specifically, how can it be that an immune response which appears in all normal human beings during the first 6 months of life also plays a role in the development of a disease? Closer examination of this question reveals that these antibodies can, and usually do, react at sites of trauma to the horny layer of the skin. This, in turn, suggests that the primary role of the stratum corneum antibodies may be to aid in the repair of skin damage. These and other relevant findings lead to a more comprehensive overview of the nature of autoimmunity as indicated in the first chapter of Part I of this book. At this point in time, researchers engaged in immunologic studies of psoriasis hold diverse views on the underlying mechanisms. Not only the stratum corneum antibodies and other humoral immune responses, but also cellular responses and combinations of cellular and humoral responses are being implicated. To aid the readers, chapters which deal primarily with the role of humoral immunity in psoriasis appear in Part II while those which focus on cellular response are in Part III. In order to encourage the sound development of this area of research we focus attention on two parameters. One relates to methodology. Since the validity of experimental

findings rests on the use of appropriate controls and the reproducibility of the results, detailed descriptions of some of the key methods used in the experimental studies described in the book appear in Part IV. Some contributors elected to describe their methods together with their experimental findings. The second parameter which we need to consider to gain a sound grasp on this field is the basic nature of autoimmunity. To characterize a reaction as an immune response it is necessary to identify the specific antigen and to demonstrate the immunologic specificity of the reaction. Furthermore, to characterize an autoimmune response the antigen must be demonstrated in the producer’s body and the specificity of this “ self” antigen must be characterized. By these criteria the only autoimmune response implicated in the etiology and/or pathogenesis of psoriasis to date are of the humoral type. This does not preclude the possibility that autoreactive cell mediated immunity may be demonstrated in the future. More immediately, cellular responses, which have to a large extent been ignored in past studies on psoriasis, do appear to play a critically important role in the pathogenesis of the disease as revealed by the diverse studies on the subject which are set forth in this book. Ernst H. Beutner and Stefania Jahfonska

TH E EDITOR Ernst H. Beutner, Ph.D., is Professor of Microbiology and Dermatology at the Medical School of the State University of New York at Buffalo. Dr. Beutner received his training at the Pennsylvania State University and the University of Pennsylvania where he received his BA and his Ph.D. in 1951. He served as Research Supervisor at the Sias Lab in Brookline, Mass, from 1951 to 1955 and at the Harvard Dental School as Research Associate until 1956. At that time he took a position at his present location as Assistant Professor at the University of Buffalo; this subsequently became the State University of New York at Buffalo. Dr. Beutner is a Fellow of the American Academy of Microbiology and a member of the American Academy of Dermatology, New York Academy of Medicine, Society for Experimental Biology and Medicine, and American Association for the Advancement of Science, and the honorary society Sigma Xi. He is Board Certified by the American Board of Medical Microbiology. He has received honors in Brazil, Poland, and Austria for his discovery of the pemphigus antibodies and for his contributions to the development of the field of immunopathology of the skin. Dr. Beutner is author/editor of three books on immunopathology of the skin and one on defined immunofluorescence as well as more than 180 literature reports. His major interests relate to the nature and function of autoimmunity in health and disease. The findings on this subject set forth in this book constitute a fascinating example of a malfunction of a normal autoimmune repair mechanism.

ACKNOWLEDGMENTS The preparation of this book was supported in part by grants from the Owen Laboratories, Division of Alcon Laboratories, the IF Testing Service, Inc., and the International Service for Immunodermatology Laboratories, Inc. The concepts and much of the research set forth in this book were evolved in over 7 years of collaborative studies with Professor Stefania Jablbnska, Dr. Tadeusz Chorzelski, Dr. Wieslaw Glinski, and Dr. Krzysztof Dabski of the Warsaw Academy of Medicine and the editor. The editor expresses his deep appreciation to these colleagues from Warsaw, Poland for their valuable contributions to the evolution of this field of study and particularly to Professor Jablbnska for help and guidance in organizing this book. The compilation of this book was, in large part done by Mrs. Gloria Griffin. The editor expresses his special appreciation to Mrs. Griffin for her help on the editing of this book and for her careful compilation of the materials in it.

CONTRIBUTORS Paul R. Bergstrasser, M.D. Associate Professor Division of Dermatology Department of Internal Medicine University of Texas Health Science Center at Dallas Dallas, Texas Ernst H. Beutner, Ph.D. Professor Departments of Microbiology and Dermatology State University of New York Buffalo, New York Walter L. Binder, Ph.D. Product Support Specialist Immunology Research and Development Calbiochem-Behring Corporation San Diego, California Lasse Roger Braathen, M.D. Associate Professor Department of Dermatology The National Hospital Oslo, Norway Otto Braun-Falco, M.D. Professor and Chairman Department of Dermatology University of Munich Munich, West Germany Tadeusz P. Chorzelski, M.D. Head, Immunopathology Laboratory Professor Department of Dermatology Warsaw Academy of Medicine Warsaw, Poland Olena Chowaniec, M.D. Chief Associate Professor Department of Dermatology Warsaw Academy of Medicine Warsaw, Poland

Enno Christophers, M.D. Professor and Chairman Department of Dermatology University of Kiel Kiel, West Germany Jacques Clot, M.D. Head, Department dTmmunologie Cellulaire Hôpital Saint-Eloi Montpellier, France Eugene M. Farber, M.D. Professor and Chairman Department of Dermatology Stanford University School of Medicine Stanford, California Ole Fyrand, M.D. Associate Professor Department of Dermatology The National Hospital Oslo, Norway Wieslaw Glinski, M.D. Assistant Professor Department of Dermatology Warsaw Academy of Medicine Warsaw, Poland Jean-Jacques Guilhou, M.D. Professor Clinique Dermatologique Cliniques Saint Charles Montpellier, France Eric R. Hurd, M.D. Professor Rheumatic Diseases Unit Department of Internal Medicine University of Texas Health Science Center at Dallas Dallas, Texas Stefania JabJonska, M.D. Professor and Head Department of Dermatology Warsaw Academy of Medicine Warsaw, Poland

Maria Jarzabek-Chorzelska, Ph.D. Associate Professor Department of Dermatology Warsaw Academy of Medicine Warsaw, Poland Warren W. Jederberg, M.D. Research Microbiologist Letterman Army Institute of Research Division of Cutaneous Hazards Presidio of San Francisco, California Hans-Kristian Krogh, M.D., Ph.D. Professor and Chairman Department of Dermatology University of Bergen Bergen, Norway Gerald W. Krueger, M.D. Head, Division of Dermatology Associate Professor Department of Medicine University of Utah College of Medicine Salt Lake City, Utah Vijay Kumar, Ph.D. Assistant Professor Departments of Microbiology and Dermatology State University of New York Buffalo, New York W. Clark Lambert, M.D., Ph.D. Assistant Professor College of Medicine and Dentistry New Jersey Medical School Newark, New Jersey

Ove J. Mellbye, M.D. Head, Department of Dermatology The National Hospital Institut of Immunology and Rheumatology Oslo, Norway Jean Meynadier, M.D. Professor and Chairman Clinique Dermatologique Cliniques Saint-Charles Montpellier, France Vera B. Morhenn, M.D. Assistant Professor Department of Dermatology Stanford University School of Medicine Stanford, California Shigeo Ofuji, M.D. Professor Emeritus Department of Dermatology Faculty of Medicine Kyoto University Kyoto, Japan Sigvald B. Refsum, M.D. Prosektor Department of Dermatology Institute of Pathology University of Oslo Oslo, Norway Genowefa Rzesa, Ph.D. Department of Dermatology Warsaw Academy of Medicine Warsaw, Poland

Andrzej Langner, M.D. Associate Professor Department of Dermatology Warsaw Academy of Medicine Warsaw, Poland

Reiner Scherer, M.D. Assistant Professor Department of Dermatology Medizinische Hochschute Lübeck Lübeck, West Germany

Ewa Maciejowska, M.D. Assistant Professor Department of Dermatology Warsaw Academy of Medicine Warsaw, Poland

Jens-M. Schröder, Ph.D. Wiss. Assistant Department of Dermatology University of Kiel Kiel, West Germany

Julie S. Sedgwick, Ph.D. Immunology Program Divisions of Dermatology and Rheumatology Department of Internal Medicine University of Texas Health Science Center at Dallas Dallas, Texas

Hachiro Tagami, M.D. Associate Professor Department of Dermatology Hamamatsu University School of Medicine Hamamatsu, Japan

Olav Tonder, M.D., Ph.D. Department of Microbiology The Gade Institute and Broegelmann Research Laboratory University of Bergen Bergen, Norway

TABLE OF CONTENTS Part I: Concepts of Autoimmunity, Genetics, and Histology of Psoriasis Chapter 1 Nature of Autoimmunity: Unified Concept and Other Theories as Related to Psoriasis......................................................................................................................... 3 Ernst H. Beutner Chapter 2 The Association of HLA and Psoriasis.........................................................................15 Vera B. Morhenn and Eugene M. Farber Chapter 3 Histology of Psoriasis: the Role of Polymorphonuclear Neutrophiles.........................21 Stefania Jablonska, Olena Chowaniec, and Ewa Maciejowska Part II: Humoral Immune Responses in Psoriasis Chapter 4 Stratum Corneum Antigens and Antibodies as Revealed by Immune Adherence and Indirect Hemagglutination............................................................................................39 Hans-Kristian Krogh and Olav T0nder Chapter 5 Immunofluorescence Findings on Stratum Corneum Antibodies, Antigens, and Their Reactions In Vitro and In Vivo as Related to Repair and Psoriasis.............................53 Ernst H. Beutner, Walter L. Binder, Stefania Jabfonska, and Vijay Kumar Chapter 6 Immunofluorescence Studies on Stratum Corneum Antibodies.................................. 81 Walter L. Binder, Ernst H. Beutner, and Stefania Jablbnska Chapter 7 IF Studies of Psoriatic Scales and Induced Psoriatic Lesions (Koebner Phenomenon)..................................................................................................................95 Stefania Jablbnska, Ernst H. Beutner, Tadeusz P. Chorzelski, Maria Jarzabek-Chorzelska, Genowefa Rzesa, Olena Chowaniec, and Ewa Maciejowska Chapter 8 Chemotactic Factors in Psoriatic Scales...................................................................... I ll Hachiro Tagami and Shigeo Ofuji Chapter 9 Role of Polymorphonuclear Leukocyte Chemotaxis in Psoriasis...............................125 Enno Christophers, Jens-M. Schroder, and Andrzej Langner Chapter 10 Immunoglobulins and Rheumatoid Factors in Psoriasis............................................. 133 Jean-Jacques Guilhou, Jacques Clot, and Jean Meynadier

Chapter 11 Immunopathologie Studies of the Joints in Psoriatic A rthritis.................................143 Ole Fyrand, Ove J. Mellbye, Lasse R. Braathen, and Sigvald B. Refsum Chapter 12 Stratum Corneum Antigens as Related to Bacteria and Sweat.................................. 155 W. Clark Lambert and Ernst H. Beutner Part III: Cellular Responses in Psoriasis and Hypotheses on Their Role Chapter 13 Immunoinflammatory Phenomena in Psoriasis......................................................... 165 Otto Braun-Falco and Reiner Scherer Chapter 14 Mononuclear Cell Function and its Relative Potential in the Pathogenesis of Psoriasis....................................................................................................................... 183 Gerald Krueger and Warren W. Jederberg Chapter 15 Cellular factors in Psoriasis and Their Interaction with Humoral Factors............... 205 Wieslaw Glinski Chapter 16 Remission of Psoriasis During Peritoneal Dialysis. A Possible Role of Polymorphonuclear Leucocytes (PMNL) and Their Neutral Serine Proteinases in the Pathogenesis of the Disease........................................................................................ 219 Wieslaw Glinski and Stefania JabJonska Chapter 17 Neutrophil Function in Psoriasis: Increased Adherence and Enhanced Superoxide Generation.................................................................................................................... 233 Paul R. Bergstresser, Julie B. Sedgwick, and Eric R. Hurd Chapter 18 Studies on Cellular Aspects of the Immune Response in Psoriasis.............................241 Jacques Clot and Jean-Jacques Guilhou Chapter 19 Hypothetical Role of Immunological Factors in Psoriasis......................................... 249 Jean-Jacques Guilhou, Jacques Clot, and Jean Meynadier Part IV: Methods for Studies of Immune and Cellular Responses in Psoriasis Chapter 20 Immune Adherence and Indirect Hemagglutination Tests for Detection of Stratum Corneum Antibodies.....................................................................................................257 Hans-Kristian Krogh and Olav Tender Chapter 21 Methods for Immunofluorescence Studies of Stratum Corneum Antibodies Ernst H. Beutner, Walter L. Binder, and Vijay Kumar

267

Chapter 22 Methods for Chemotaxis Studies of Psoriatic Scales................................................. 283 Hachiro Tagami and Shigeo Ofuji Chapter 23 Hemadsorption Techniques for the In Situ Characterization of Mononuclear Cells in T issue...........................................................................................................................291 Olav Tender and Hans-Kristian Krogh Index.............................................................................................................................301

Part I: Concepts of Autoimmunity, Genetics, and Histopathology of Psoriasis

3 Chapter 1 NATURE OF AUTOIM M UNITY: UNIFIED CONCEPT AND OTHER THEORIES AS RELATED TO PSORIASIS* Ernst H. Beutner TABLE OF CONTENTS I.

Introduction...........................................................................................................4

II.

Comparisons of SCAb with Pemphigus Antibodies.......................................... 4 A. In Vitro Serologic Reactions of SC and Pemphigus Antibodies...............4 B. Tissue Culture Reactivity of SC and Pemphigus A ntibodies.................. 4 C. In Vivo Reactivity of SC and Pemphigus A ntibodies..............................6 D. Relation of Theories of Autoimmunity to Properties of SC and Pemphigus Antibodies and Their Antigens and to Other Forms of Autoimmunity............................................ 6

III.

Theories and Concepts on Autoimmunity...........................................................8 A. Unified Concept of Autoimmunity — Pathogenesis................................ 8 B. Unified Concept on the Etiology of Autoimmune Reactions.................. 9 1. H Self Conversion...........................................................................9 2. Abnormal T and B Cell Interaction............................................. 10 3. Abnormal Antigenic Stimuli......................................................... 10

IV.

Evaluation of T Cell Functions and SCAb Reactions in Psoriasis....................11 A. T Cell Function Tests in Psoriasis............................................................ 11 B. Evaluation of Findings on SCAb and T Cells in Psoriasis......................12

References........................................................................................................................12

*

The preparation of this chapter was supported by grants from the Owen Laboratories, Division of Alcon Laboratories, the IF Testing Service and the International Service for Immunodermatology Laboratories (ISIL).

4

Autoimmunity in Psoriasis I. INTRODUCTION

The extent of variation in the nature of diverse forms of autoimmunity is well illustrated by comparisons of some of the salient properties of the stratum corneum antibodies (SCAb) which are implicated in the pathogenesis of psoriasis (see Section II.C and Chapters 4 to 9, 11 and 12) with relevant properties of pemphigus antibodies which are now recognized as the causative agents of pemphigus.28 The most salient data are reviewed in the following section. II. COM PARISONS OF SCAb W ITH PEM PHIG US ANTIBODIES The following Table 1 summarizes the major similarities and differences between SC and pemphigus antibodies. Most of the similarities between diverse forms of autoimmunity including the SC and pemphigus antibodies appear in the characteristics demonstrable by in vitro serologic test systems while the most important differences occur in their behavior in vivo and frequently in cultural studies of tissue explants. A. In Vitro Serologic Reactions of SC and Pemphigus Antibodies Both SC and pemphigus antibodies share the one property which is common to all forms of autoimmunity, notably they can undergo specific serologic reactions with antigens of the antibody producers.2 (Chapters 4 to 6). The SC antigens are located at least in part on the cell surfaces in the horny layer (Chapters 5 to 7, and 13) while the pemphigus antibodies react with cell surface antigens in the prickle cell layer.8 Biochemically the SC antigens include both proteins and carbohydrates (Chapter 5) while the pemphigus antigens of humans are proteins.2 Both groups of autoantibodies can be detected at least in part by indirect immunofluorescence and both include at least some antibodies of the IgG class.2 (Chapters 4 to 6). The SC antibodies fix complement in vitro while the pemphigus antibodies fail to do so. These comparisons of similarities and differences in the characteristics of serologic reactions of SC and pemphigus antibodies and their antigens afford little or no indications of the fundamental differences between them. The first of the properties of these two types of autoantibodies in the listing in Table 1 that points to the basic differences between them is their natural occurrence in human sera. SCAb occur in all normal sera while the pemphigus antibodies are highly disease specific; detection of pemphigus antibodies is a valuable diagnostic test.817 B. Tissue Culture Reactivity of SC and Pemphigus Antibodies The most clear-cut demonstration of the basic differences between SC and pemphigus antibodies is seen in the contrasts of their behavior in tissue culture. The SC antigens of explants of normal skin cultured on sera containing SC antibodies of a titer of 40 to 80 or more fail to undergo reactions demonstrable by direct immunofluorescence; however, indirect immunofluorescence tests of frozen sections of the same explants with the same sera in which they are cultured yield strongly positive reactions (see Chapters 5 and 6). These observations indicate that the SC antigens of normal skin exist in a hidden or nonreactive form but that the process of preparing frozen sections of them converts them to a reactive form. The nature of this phenomenon is demonstrable by bathing skin explants in sera containing SCAb. SC antigens of untreated skin explants fail to react even when cultured with SC facing down. But explants of skin gently swabbed with acetone or ether on the SC side and then cultured in sera containing SCAb do undergo reactions on

5 Table 1 COMPARISON OF STRATUM CORNEUM (SC) AND PEMPHIGUS AUTOANTIBODIES Properties In vitro reactions Autoreactive Antigen location Nature of antigen Detected by indirect IF Ig class o f antibodies Fixation of complement Occurrence of antibodies Tissue culture reactivity of antibodies with normal skin with traumatized skin Effects o f tissue culture reaction of antibodies In vivo reactions of antibodies with normal skin with traumatized skin Responses to in vivo binding of antibodies

Pemphigus antibodies

SC Antibodies

Yes Stratum spinosum Protein Yes IgG No Only in pemphigus

Yes Stratum corneum Carbohydrate and protein Yes IgG, IgM Yes All normal sera

Yes (Not relevant) Acantholysis

No Yes None detectable

Yes (not relevant) Induction of acantholytic bullae of pemphigus

No Yes (a) Aid in normal removal of traumatized SC (b) Abnormally extensive reaction of SCAb play role in psoriasis

the surface of the SC; comparable swabbing with buffered saline fails to render the SC antigens reactive (Chapter 5). These observations indicate that the failure of normal SC antigens of skin explants to react with SCAb is not due to the failure of the antibodies to cross the anatomical barriers of the skin but rather to chloroform and ether soluble lipids which coat or are loosely bound to the surface of the SC and which normally hide the SC antigen from reactivity with SCAb. The same basic phenomenon can also be demonstrated by scratching (Chapter 6) or cutting (Chapter 5) the SC of skin explants and exposing them to SCAb. Such trauma also serves to convert the SC antigens from their normal hidden or nonreactive to a reactive form as seen by the binding of SCAb and their fixation of complement at the site of trauma. However, the observed binding of SCAb and fixation of complement either at the sites of trauma or on surfaces of SC swabbed with chloroform or ether produce no histologic changes in the explants that are demonstrated by the methods used to date. Pemphigus antibodies, unlike the SC antibodies, do bind to their homologous antigens in explants of normal skin. Furthermore, such skin explants grown in sera containing pemphigus antibodies in titers of 40 or 80 or more for 24 to 72 hr also undergo histopathologic changes comparable to those of the bullae which characterize the human disease.10 22,28 In effect, the reactive antigens on the surface of cells in the prickle cell layer are accessible to binding by the pemphigus antibodies and at higher concentrations produce characteristic histologic changes. In summary, in vitro studies by indirect immunofluorescence and other serologic methods as well as tissue culture studies of skin explants show that the SCAb which occur in all normal human sera are directed against hidden antigens while the pemphigus antibodies which occur only in sera of pemphigus patients are directed to accessible antigens. Also, while pemphigus antibodies produce histopathologic changes, SCAb

6

Autoimmunity in Psoriasis

have failed to do so thus far. The significance of these differences is, to some extent, clarified by comparison of the behavior of these two autoantibodies in vivo. C. In Vivo Reactivity of SC and Pemphigus Antibodies In vivo SC antibodies fail to react with their homologous antigens in the horny layer of normal skin as seen by direct immunofluorescent staining for bound IgG in the SC. However, in vitro tests of frozen sections of skin by indirect immunofluorescence tests performed with the SCAb of the skin donors yield positive reactions, thus demonstrating that both SC antigen and SCAb are present and that the latter are autoantibodies (Chapters 4 and 5). At sites of scratches or other trauma of the skin the SCAb do appear to react in vivo as revealed by direct immunofluorescent staining for IgG and complement of the site of scratching. (Evidence for the SCAb nature of the IgG bound to the SC antigen sites derives in part from controlled studies of comparable reaction patterns in the above-mentioned tissue culture studies. Other lines of evidence are reviewed in Chapter 5.) The available evidence suggests that the normal in vivo responses to the binding of SC antibodies and their fixation of complement at sites of reaction include the release of C3 chemotaxins and the resultant attraction of polymorphonuclear leucocytes (Chapters 5 to 8). The latter probably aid in the removal of damaged SC components that are not adequately degraded by hydrolytic enzymes. This apparent role of SC antibodies may be referred to as an aid to the “ normal clearing mechanisms” for damaged horny layer components. (Other mechanisms include exfoliation and degradation by hydrolytic enzymes.) It may well be that the in vivo binding of SC antibodies and their fixation of complement contribute to the normal repair mechanisms of skin at sites of trauma not only by aiding in the normal clearing but also by other mechanisms such as the induction of normal hyperproliferative responses which accompany wound repair (Chapter 3). Under abnormal conditions an excessive amount of conversion of SC antigens from their normal hidden or nonreactive form to a reactive form occurs together with the resultant in vivo binding of SCAb and their fixation of complement. Several lines of evidence set forth in this book (Chapters 4 to 8) indicate that this is a key factor in the underlying mechanism of psoriasis. The most striking evidence available to date is that the binding of SCAb and their fixation of complement appears to precede the development of histologically and clinically typical psoriatic lesions in the scratch induced Kóebner phenomenon (Chapter 7). In contrast to the SCAb, pemphigus antibodies are capable of binding in vivo to their homologous antigen in the prickle cell layer of normal skin as seen by direct immunofluorescence tests for IgG deposits.28 This, in fact, is an important diagnostic test for pemphigus.17 The extent of binding is a function of the titer of the pemphigus antibodies and of the severity of the disease. In areas of strongly positive binding a positive Nikolsky sign can be elicited or spontaneous pemphigus bullae may arise. Skin sites at which such responses occur can, of course, no longer be considered clinically normal; in effect, high concentrations of bound pemphigus antibodies elicit pathologic changes in vivo.8 Importantly, the pemphigus antibodies also bind in vivo in passively sensitized animals and produce acantholytic lesions in areas in which the amount of bound antibody is sufficiently high.7 D. Relation of Theories of Autoimmunity to Properties of SC and Pemphigus Antibodies and Their Antigens and to Other Forms of Autoimmunity No one of the theories on autoimmunity included in the classic teachings of immunology afford a satisfactory basis for interpreting the properties of both the SC and

7 Table 2 DISTINCTION BETWEEN PHYSIOLOGIC AND PATHOLOGIC AUTOIMMUNITY AS CHARACTERIZED BY THE UNIFIED CONCEPT Characteristics Self antigens In vivo reactions In vitro reactions

Autoimmunity Occurrence

Pathologic autoimmunity

A self — accessible to in vivo reaction in normal tissue Reactive — not distinctive; often to surface antigens

H self — hidden or novel or inaccessible in normal tissue Reactive — not distinctive; often to cytoplasmic or nuclear antigens

Rare disease specific

Either universal or in blood stream of some but not all; Readily induced in normal subjects

Either cannot be induced in normals or induced under special conditions only Etiologies o f in vivo reactions implicated Inducible Not induced to date Subtypes No No H self to H(R) self conversion“ Some Most Abnormal T and B cell Yes Yes function Some Most Abnormal immunogenic Yes No stimuli Examples ThyroglobuNative DNA Antigens (Ag) & relevant lin SLE6 diseases Thyroiditis e.g. Rh(e) IC6 Ag (protein) pemAntigens (Ag) & relevant phigus Ag diseases Autoimmune hemolytic anemia Theories & concepts Induction in normal subjects

Restricted

Universal

° *

Physiologic autoimmunity

In some normals Yes Most No Yes Wasserman Ag (cardiolipin) None Altered IgG Rheumatoid arthritis

Universal Yes

No No Stratum corneum Ag Psoriasis T Ag of RBC1 HTF6 hemolytic anemia

Ehrlich’s horror autotoxicus; Burnet’s Grabar’s transporteur theory forbidden clone; T suppressor cell function Unified concept of autoimmunity (applies to both pathologic and physiologic autoimmunity)

See text for explanation. IC = intercellular antigen of stratified epithelium; RBC = red blood cells; HTF = Huebener, Thomsen, Friedenreich; and SLE = systemic lupus erythematosus.

pemphigus antibodies listed in the first three sections in Table 1 and described in the above three subsections. As indicated in Table 2 the properties of SCAb and their antigens can best be explained in terms of Grabar’s “ transporter” theory.15The properties of pemphigus antibodies might to some extent be explained in terms of Ehrlich’s “ horror autotoxicus” 11 and its latter day variants including Burnet’s “ forbidden clone” theory.5 To attain a rational basis for an understanding of the properties of both the SCAb-antigen reactions and pemphigus antibodies-antigens system we must adopt the “ unified concept” of autoimmunity3 summarized in the following section. This unified concept affords a basis for understanding not only the SC and pemphigus types of autoimmunity but also of the diverse forms of autoimmunity observed in systemic lupus erythematosus and related connective tissue diseases.

8

A utoimm unity in Psoriasis

III. THEORIES AND CONCEPTS ON AUTOIMMUNITY Ehrlich’s horror autotoxicus theory,11 Burnet’s forbidden clone theory,56 Witebsky’s postulates,32 and modern theories on the role of T suppressor cell and T helper cell function have aided the development of our understanding of the role of autoimmunity in diseases such as pemphigus,2 systemic lupus erythematosus,6 21 acquired autoimmune hemolytic anemia,26 and Hashimoto’s thyroiditis.33 A primary reason is that these and other comparable theories and concepts have focused attention on the pathologic potential of the “ forbidden clone” type of autoimmunity. Developments in our understanding of the role of the SCAb type of autoimmunity in psoriasis has, on the other hand, been aided more by Grabar’s transporteur theory on autoimmunity15 because these antibodies whose in vivo reactions appear to precede the development of psoriasis (and occur in virtually all active psoriatic lesions) are of a “ nonforbidden clone” or physiologic type. The converse also holds true; that is, Grabar’s transporteur theory is misleading in dealing with such problems as the role of autoimmunity in pemphigus; and the horror autotoxicus and forbidden clone theories and their latter day variants have not proven to be relevant to studies on the role of nonforbidden clone type of autoimmunity such as that of SCAb. The unified concept of autoimmunity of Beutner et al.3 affords both concepts and functional guidelines for distinguishing between “ pathologic” and “ physiologic” forms of autoimmunity and for differentiating three basic etiologic mechanisms as indicated in the following sections. These concepts are largely a restatement of experimental observations of the type set forth in this section. A. Unified Concept of Autoimmunity — Pathogenesis This group of concepts3 can be restated briefly as follows. The unique feature of autoimmunity is the capacity of autoreactive cell mediated immunity and/or autoantibodies to react in vivo with their producers own tissues. From the viewpoint of the producers the most important considerations are the effects o f the in vivo reactions o f autoantibodies or o f autoreactive cell mediated immunity on their producer. Either pathologic or so-called physiologic responses may result from their in vivo reactions. The basic difference between these two forms of autoimmunity lies in the accessibility of the autologous antigens to in vivo reactions in the normal state. That is, pathologic autoimmune responses are usually directed against antigens which are normally accessible to in vivo reactions. They may be referred to as A self antigens. Examples of A self are the antigens reactive with pemphigus antibodies3 and with the glomerular basement membrane (GBM) antibodies31 and with the red blood cell Rh antibodies in AIHA.26 The so-called physiologic forms of autoimmunity, on the other hand, are directed to autologous antigens which are normally inaccessible or hidden from in vivo reaction.27 These antigens may be referred to as H self. H self can take the form of altered or novel or sequestered antigens. Pathologic and physiologic forms of autoimmunity differ from each other not only with regard to the above mentioned A self and H self nature of the autologous antigens but also in several other respects as indicated in Table 2. Pathologic forms of autoimmunity tend to be rare and disease specific, e.g., pemphigus antibodies2 and antibodies to Rh antigens.26 In contrast to this, physiologic autoimmunity occurs in either some or all normal sera. Another difference is that physiologic autoimmune responses which are not already present in a normal individual can be elicited readily by immunization while purely pathologic autoimmunity either cannot be elicited in normal subjects or is difficult to induce by immunization with antigens. Examples of these two types of autoimmunity are given in Table 2.

9 The physiologic autoimmunity to H self antigens is basically of two types, universal autoimmunity which occurs in essentially all normal subjects and autoimmunity which can only be detected in some but not all normals. Examples of universal autoimmunity are the antibodies to T antigens on red cells involved in Huebener, Thomsen, Friedenreich hemolytic anemia and the SCAb which are now implicated in the pathogenesis of psoriasis (see Section II). Examples of physiologic autoantibodies which occur less commonly in normal sera are the Wassermann antibodies9 and rheumatoid factor.23 Both can be induced readily by immunization. While the laboratory findings in studies of inducible pathologic autoimmune responses and physiologic autoimmunity that occurs only in some, but not all, normal sera are somewhat comparable, their etiology is quite different as outlined in Table 1 and described in the following section. B. Unified Concept on the Etiology of Autoimmune Reactions According to the unified concept the in vivo reactions of autoantibodies or of autoreactive cell mediated immunity with the producer’s own tissue antigen causes the most relevant changes. While other theories serve to focus our attention on the etiology of autoimmune responses themselves the unified concept guides us to consider also changes in normal autologous antigens from nonreactive to reactive forms which lead to in vivo reactions with nonforbidden clone or physiologic autoimmunity such as SCAb. The role of this type “ H self conversion” in the etiology of a human disease as illustrated by the immunologic reactions that cause the Huebener, Thomsen, Friedenreich autoimmune hemolygic anemia (see next subsection). In effect, three distinct etiologic mechanisms are implicated in precipitating in vivo reactions of autoimmune responses. 1. H Self Conversion Since physiologic autoimmune responses of the universal type such as the SCAb fail to react in vivo with their normal autologous antigens but do react with altered or abnormal autologus antigens, the etiology of their in vivo reaction is the appearance or formation of reactive forms of the self antigens, i.e., the conversion of the H self antigens from their normal nonreactive form to a reactive or H(R) self form. The converted H(R) self form of antigens not only react in vivo but appear to serve as the immunizing antigens that elicit at least some types of physiologic autoimmunity. This conversion can be caused by diverse factors. These include: (1) senescence of red blood cells releases T antigens,18 (2) infections which release enzymes or cause the development of novel antigens, e.g., EB virus infections which cause the release of novel “ heterophile” antigens,20 and (3) biochemically mediated genetic predispositions to conversion reactions which may play a role in some forms of physiologic immunity. Huebener, Thomsen, Friedenreich (HTF) autoimmune hemolytic anemia affords the classic example of a disease caused by H self conversion. It has been recognized for over 50 years that HTF hemolytic anemia is caused by autoantibodies to T antigens of red blood cells.14 24 26 These anti T antibodies are present in all normal sera but fail to react with normal red blood cells because the T antigens are hidden by neuraminic acid. When red cells are treated with neuraminidase the T antigens convert from their normal, nonreactive (H self) to a reactive (H[R]) self) form. As a sequela to certain bacterial infections the T antigens convert, resulting in hemolytic episodes which may be fatal. The current views on the normal role of anti T antibodies is that they aid in the removal of senescent red blood cells.18 The anti T antibodies are only an example of such physiologic autoantibodies. Normal sera can contain Tn antibodies24 to another hidden red cell antigen, Ts antibodies to sperm antigens hidden by neuraminic acid32 and autoantibodies to various other cellular antigens which are rendered reactive by treatment with neuraminidase.25 28 30 32

10

A utoimm unity in Psoriasis

In essence, the anti T antibodies afford an example of a physiologic autoimmune response which may serve as an aid in the removal of damaged or senescent cells and which can under certain abnormal conditions play a role in a pathologic process. Several lines of evidence set forth in this book indicate that SCAb play a comparable role in the pathogenesis of psoriasis (see Chapters 8, 9, 20, and 21). That is the etiology of both HTF hemolytic anemia and psoriasis appears to be an abnormal conversion of H self to H(R) self. The role of SCAb may be compared to that of the antibodies to the T antigens of red cells. As indicated above (Section II.B.), tissue culture studies demonstrate that antigens of the horny layer of skin which are normally in a form that is nonreactive with SCAb undergo conversion to a reactive form by extraction with acetone or ether or as a result of trauma, e.g., cuts or scratches (see below and Chapters 5 and 6). Since the SCAb occur in all normal sera there is little justification for regarding them either as abnormal autoimmune responses or as the etiologic factor responsible for in vivo reactions with SC antigens; it is more realistic to regard trauma as an etiologic factor which causes H self conversions. As indicated above it seems probable that the SCAb normally play the role of agents which aid in the removal of damaged, undegraded components of the horny layer. 2. Abnormal T and B Cell Interaction Pathologic autoimmunity is of itself an abnormal pathogenetic factor in diseases such as systemic lupus erythematosus (SLE) and probably in a small percentage of the patients suffering from pemphigus. These diseases are characterized by a diversity of abnormal autoantibodies, some of which are clearly pathological, e.g., the antinative DNA,1. Also, pemphigus antibodies clearly play a pathologic role (regardless of their etiology) as demonstrated by the induction of typical acantholytic lesions which can be produced in skin by passive transfer of pemphigus antibodies25 as well as by the above mentioned studies on explants grown in the presence of pemphigus antibodies.1022 28 An etiologic mechanism in the production of pathologic autoimmune responses of SLE and related connective tissue disease as well as in a few cases of pemphigus is an abnormal T cell function and/or T and B cell interaction. Autoimmune diseases with this type of etiology may be characterized by the appearance of diverse abnormal forms of autoimmunity. Thus the coexistence of pemphigus with thymonas and myasthenia gravis,2 SLE,8 with bullous pemphigoid,16“ and with other forms of pathologic autoimmunity2 affords rather strong circumstantial evidence for abnormal T cell function and/or T and B cell interaction. On the other hand, the suppression of T cell counts in peripheral blood is not a valid indication of suppression of T cell function. Also, suppression of T cell counts is not a true indicator of abnormalities in immunologic reactivity of T cells because it affords no measure of T cell responses to specific antigens. 3. Abnormal Antigenic Stimuli Pathologic autoimmunity can also be elicited in immunologically normal subjects by abnormal antigenic stimuli. An obvious demonstration of this is seen in experimental thyroiditis.33 Both thyroid autoimmunity and thyroiditis can be produced reproducibly by immunization of normal rabbits, rats, and monkeys with thyroglobulin in complete Freund’s adjuvant.33 Similarly, experimental allergic encephalomyelitis can be induced by immunization of normal rabbits, guinea pigs, etc. with brain or other CNS antigens with the same adjuvant13 and aspermatogenesis can be elicited reproducibly in normal guinea pigs by immunization with testicular antigens with this adjuvant.12 A somewhat comparable mechanism is implicated in the etiology of certain human

11

autoimmune diseases. This, for example, appears to be the etiology of Brazilian pemphigus foliaceus. This is clearly a form of true pemphigus as revealed not only by the clinical and histologic signs of the disease19 but also by the immunologic findings of pemphigus antbodies in sera of these patients,4 by the in vivo binding of these antibodies and the induction of acantholytic lesions in passive transfer experiments34 and by the apparent in vivo binding seen in the form of intercellular deposits of IgG in skin biopsies in Brazilian pemphigus. However, Brazilian dermatologists regard this as an infectious disease because of its striking epidemiologic distribution. It occurs only in well circumscribed endemic regions; all ethnic groups living in these regions appear to be afflicted. While both relatives and neighbors living in these areas may have the disease, relatives outside of them do not suffer from this form of pemphigus. Also, patients suffering from Brazilian pemphigus foliaceus have no other detectable immunologic abnormalities. If we accept the available epidemiologic and immunologic findings it appears that Brazilian pemphigus foliaceus is an autoimmune disease caused by some as yet unidentified infectious agent which serves as an abnormal antigenic stimulus for the development of a single abnormal pathologic autoantibody in immunologically normal subjects. While patients with the active form of this disease have “ suppressed T cell function” as revealed by T cell counts this appears to be a secondary event; there is no immunologically valid evidence to suggest that these are either disease specific or immunologically specific or primary changes or an etiologic factor. Essentially comparable mechanisms are implicated in the heart disease syndrome caused by certain strains of type 5 of group A beta hemolytic streptococci which appear to have antigens cross reactive with heart tissue. These bacteria can elicit autoimmunoresponses to heart tissue in immunologically normal rabbits and apparently also in humans.16 In this situation the microbial antigens are more clearly defined though the pathologic significance of the heart autoantibodies which they elicit appears to be somewhat less certain. In brief, the three basic etiologic mechanisms can cause in vivo reactions in autoimmunity: (1) the conversion of autologous antigens from nonreactive H self to H(R) self forms which are reactive with physiologic autoantibodies, (2) the development of pathologic autoimmunity as a result of abnormal T cell function or T and B cell interaction, and (3) the development of pathologic autoimmunity in response to abnormal antigenic stimuli. IV. EVALUATION OF T CELL FUNCTIONS AND SCAb REACTIONS IN PSORIASIS A. T Cell Function Tests in Psoriasis The peripheral blood lymphocytes of patients with active psoriasis have suppressed T cell counts as revealed by tests of E rosette formation, normal B cell counts as shown by immunofluorescence staining for surface Ig, and increased null cell counts as seen by differences between T and B cell counts (Chapters 15, 18, and 19). Kinetic studies of peripheral blood lymphocytes reveal that these changes occur after the onset of the clinically active disease process (Chapter 15). On the basis of this finding the observed changes in T cell function are secondary events which do not play an etiologic role in the development of psoriasis. The observed suppression of T cell function appears to be due to humoral factor(s) as revealed by studies of the action of sera from patients with active psoriasis on normal peripheral lymphocytes (Chapter 14). This observation indicates that even as secondary events the suppression in T cells is not associated with true cell mediated immunity but rather with some unidentified humoral factor. Since psoriatic sera do

12

Autoimmunity in Psoriasis

contain immune complexes (Chapter 13) and since these complexes are capable of suppressing T cell function it may be that they are (in part or wholly) responsible for the observed changes in active cases of psoriasis. In vitro studies of peripheral lymphocytes from patients with active psoriasis reveal that the suppression of T cells can be reversed by Concanavalin A (Chapter 15). In brief, it appears that the observed suppression of T cells from patients with active psoriasis is not only a secondary event which is mediated by humoral factors but is also reversible both in vitro and during periods of remission of the disease. This, taken together with the fact that T cell counts are not, in reality, tests of their immunologically specific reactivity indicates clearly that it is inappropriate to regard the observed suppression in T cell counts as evidence for a role of abnormal autoreactive cell mediated immunity or T suppressor cell function in the etiology of psoriasis. The histologic findings of the appearance of lymphocytic infiltrates which follow the appearance of polymorphonuclear leucocytes in the early phases of lesion development in psoriasis (Chapter 3) suggest that some autoreactive cell mediated immune responses may be operative in the pathogenesis of the disease. However, none of the immunologic studies on specific autologous antigens have revealed the presence of a specific autoreactivity. The failure to find such autoreactions, however, does not preclude the possibility of their existence. The histologic findings clearly point to the need for further immunologic studies to search for autoreactive antigens of the skin. B. Evaluation of Findings on SCAb and T Cells in Psoriasis To evaluate the relevance of findings on the role of autoimmunity in psoriasis which are set forth in this book we need to consider two generalizations: (1) valid immunologic studies of autoimmunity are based on studies of specific immune responses, be they humoral or of cell mediated or both; i.e., reactions with specific identifiable autologous antigens must be demonstrable to show that some form of autoimmunity is under consideration, and (2) autoimmune reactions which precede the development of a disease are obviously more relevant to its pathogenesis than those which appear after the disease has developed. Basically two groups of studies described in this book implicate the role of autoimmunity in psoriasis. One relates primarily to the role of stratum corneum antibodies (SCAb) (Chapters 4 to 8, 11 and 12) and the other to suppression of T cell function (Chapters 15 and 18). The available evidence suggests that both of the above generalizations hold true of the SCAb but that neither has, to date, been shown for a cell mediated immune response. However, we cannot rule out the possibility that future studies will reveal immunologically specific cell mediated immune responses which come into play in the course of the disease.

REFERENCES 1. Aarden, L. A ., de Groot, E. R., and Feltkamp, T. E. W ., Immunology o f DNA. III. Crithidia iuciliae, a simple substrate for the determination of anti-dsDNA with the immunofluorescence technique, Ann. N. Y. Acad. Sci.f 254, 505, 1975. 2. Beutner, E. H. and Chorzelski, T. P ., Experimental studies on autosensitization in bullous diseases and on transfer of pemphigus, in Immunopathology o f the Skin: Labeled A n tibody Studies, Beutner, E. H ., Chorzelski, T. P ., Bean, S. F., and Jordon, R. E., Eds., Dowden, Hutchinson & Ross, Stroudsburg, Pa., 1973, 330.

13 3. Beutner, E. H ., Chorzelski, T. P ., and Binder, W. L., Nature of autoimmunity: pathologic versus physiologic responses and a unifying concept, in Im m unopathology o f the Skin, 2nd ed., Beutner, E. H ., Chorzelski, T. P., and Bean, S. F., Eds., John Wiley & Sons, New York, 1979, 147. 4. Beutner, E. H ., Prigenzi, L. S., Hale, W. L., Lerne, C. A ., and Bier, O. G., Immunofluorescent studies o f autoantibodies to intracellular areas of epithelia in Brazilian pemphigus foliaceus, Proc. Soc. Exp. Biol. M ed., 127, 81, 1968. 5. Burnet, M ., Autoimmune disease as a breakdown in immunological hemeostasis, in Cellular Immunology, Cambridge University Press, England, 1970, 255. 6. Burnet, M ., Autoimmune disease. II. Pathology of the immune response, Br. Med. J., 2, 720, 1959. 7. Chorzelski, T. P ., Beutner, E. H ., and Jarzabek, M ., Passive transfer of pemphigus to experimental animals, Int. Arch. Allergy, 39, 106, 1970. 8. Chorzelski, T. P ., Jablonska, S., and Beutner, E. H ., Clinical significance of pemphigus antibodies, in Im m unopathology o f the Skin: Labeled Skin Antibodies, Beutner, E. H ., Chorzelski, T. P ., Bean, S. F., and Jordon, R. E., Eds., Dowden, Hutchinson & Ross, Stroudsburg, Pa., 1973, 25. 9. Deicher, H. R. G., Holman, H. R., and Kunkel, H. G ., Anti-cytoplasmic factors in the sera of patients with systemic lupus erythematosus and certain other diseases, Arthr. Rheum., 3, 1, 1960. 10. Deng, J-S, Beutner, E. H ., Shu, S., and Chorzelski, T. P ., Pemphigus antibody action on skin explants. Kinetics of acantholytic changes and stability of antigens in tissue cultures of normal monkey skin explants, Arch. Derm atol., 113, 923, 1977. 11. Ehrlich, P. and Morgenroth, J., Ueber haemolysine. Dritte Mitteilung, Berl. klin. Wchnschr., 37, 453, 1900. 12. Freund, J., Lipton, M. M ., and Thompson, G. F., Aspermatogenesis in the guinea pig induced by testicular tissue and adjuvants, J. Exp. M ed., 97, 711, 1953. 13. Freund, J., Stern, E. R., and Pisanti, T. M ., Isoallergic encephalomyelitis and radiculitis in guinea pigs after one injection of brain and mycobacteria in water-in-oil emulsion, J. Immunol., 57, 179, 1947. 14. Friedenreich, V ., Forgesetzte Untersuchungen über bakterielle umformong der isoagglutinatorischen Verhältnisse der blutkörperchen in vitro, Acta Med. Scand., 26, 308, 1927; as cited from TisserandJochem, E. M ., Behring Inst. M itt.,55, 197, 1974. 15. Grabar, P ., Hypothesis. Auto-antibodies and immunological theories: an analytical review, Clin. Immunol, and Im m unopathol., 4, 453, 1975. 16. Kaplan, M. H ., Autoimmunity to heart, in Textbook o f Immunopathology, 2nd ed., Meischer, P. A. and Müller-Eberhard, H. J., Eds., Grune & Stratton, New York, 1976. 16a. Kumar, V., Binder, W ., Schotland, E ., Beutner, E. H. and Chorzelski, T. P ., Coexistence of bullous pemphigoid and systemic lupus erythematosus, Arch. Derm atol., 114, 1187, 1978. 17. Jab&nska, S., Chorzelski, T. P ., Beutner, E. H. et al., Indications for skin and serum immunofluorescence in dermatology, in Imm unopathology o f the Skin, 2nd ed., Beutner, E. H., Chorzelski, T. P., and Bean, S. F., Eds., John Wiley & Sons, New York, 1979, 3. 18. Lauf, P. K., Blood group antigens and membrane permeability in erythrocytes of man and ruminants. An immunophysiologic approach, Proc. 5th Convocation Center for Immunol., S. Karger, Basel, 1976,383. 19. Lever, W. F., Pemphigus and Pemphigoid, Charles C Thomas, Springfield, 111., 1965. 20. Merrick, J. M ., Schifferle, R., Zadarlik, K., Kano, K., and Milgrom, F., Isolation and partial characterization of the heterophile antigen of infectious mononucleosis from bovine erythrocytes, J. Supramolecular Struct., 6, 275, 1977. 21. Miescher, P. A ., Paronetto, F., and Lambert, P. H ., Systemic lupus erythematosus, in Textbook o f Immunopathology, 2nd ed., Miescher, P. A. and Müller-Eberhard, H. J., Eds., Grune & Stratton, New York, 1976, 963. 22. Michel, B. and Ko, C. S., An organ culture study of pemphigus acantholysis, Br. J. Dermatol., 96, 295,1977. 23. Milgrom, F. and Witebsky, E ., Studies on the rheumatoid and related serum factors. I. Autoimmunization of rabbits with gammaglobulin, JAM A, 174, 56, 1960. 24. Pirofsky, B., Autoimm unization and the Autoimm une H em olytic Anemias, Williams & Wilkins, Baltimore, 1969. 25. Poschmann, A . and Fischer, K., Neuraminidase action in vivo: immunofluorescent detection of cryptantigens, in Behring Institute Mitteilungen Symposium on Neuraminidase, Behringwerke, Marburg, 1974, 129. 26. Race, R. R. and Sanger, R., Blood Groups o f Man, 6th ed., Blackwell Scientific, Oxford, 1975. 27. Rosenberg, S. A. and Rogentine, G. N ., Jr., Natural human antibodies to “ hidden” membrane components, Nature New Biol., 239, 203, 1973. 28. Schlitz, J. R. and Michel, B., Production of epidermal acantholysis in human skin in vitro by the IgG fraction from pemphigus serum, J. Invest. Derm atol.,67, 254, 1976.

14

A utoimm unity in Psoriasis 29. Schlesinger, M. and Chaouat, M ., The exposure of autoantigenic determinants on the cell surface and murine thymocytes following neuraminidase treatment, Behring Inst. M itt., No. 55, 216, 1974. 30. Sedlacek, H. H . and Seiler, F. R., Dose dependency of the effect of syngenic, vibrio-cholerae-neuraminidase-treated mastocytoma cells on the life span of DBA f/2 mice, Behring Inst. M itt., No. 55, 343, 1974. 31. Stebley, R. W ., Glomerulonephritis induced in sheep by injections of heterologous glomerular basement membrane and Freund’s complete adjuvant, J. Exp. M ed., 116, 253, 1962. 32. Tisserand-Jochem, E. M ., Natural autoantibodies against neuraminidase-treated cells in normal sera and seminal plasma, Behring Inst. M itt., No. 55, 197, 1974. 33. Witebsky, E ., Rose, N. R., Terplan, K., Paine, J. R., and Egan, R. W ., Chronic thyroiditis and autoimmunization, JA M A , 164, 1439, 1957. 34. W ood, G. W ., Beutner, E. H ., and Chorzelski, T. P ., Studies in immunodermatology. II. Production of pemphigus-like lesions by intradermal injection of monkeys with Brazilian pemphigus foliaceus sera, Int. Arch. Allergy, 42, 456, 1972.

15 Chapter 2 THE ASSOCIATION OF H LA AND PSORIASIS Vera B. Morhenn and Eugene M. Farber TABLE OF CONTENTS I.

Introduction.........................................................................................................16

II.

HLA Associated with Psoriasis in Different Races............................................ 16 A. HLA Associated with Psoriasis in Caucasian Populations.................... 16 B. HLA Associated with Psoriasis in Non-Caucasian Populations............ 17 C. Family Studies in Caucasians and O rientals........................................... 17 D. Significance of Studying HLA in Different R aces................................. 18

III.

Segregation of HLA with Clinical Features of Psoriasis...................................18 A. Age of Onset and Severity of the Disease.................................................18 B. Relationship of HLA to Infection ExacerbatedPsoriasis....................... 18 C. HLA in Pustular Psoriasis........................................................................ 18 D. Psoriasis and Seronegative Polyarthritis.................................................18

IV.

The Significance of the HLA D ata..................................................................... 19 A. HLA as a Genetic Marker to Separate Clinical Subgroups.................... 19 B. HLA May Give Clues to the Etiology of Psoriasis..................................19

References....................................................................................................................... 19

16

A utoimm unity in Psoriasis I. INTRODUCTION

A variety of human diseases are associated with certain human-leukocyte-antigens (HLA) at a higher frequency than is found in the control population. Among the diseases that show a strong association are multiple sclerosis, ankylosing spondylitis, and coeliac disease.1522 Of the dermatological diseases manifesting a correlation to HLA, Reiter’s disease, dermatitis herpetiformis, and psoriasis show the strongest association.15 Interestingly, the most striking associations are found in those diseases that demonstrate a genetic pattern or manifest themselves on the skin.11 The demonstration of genetic linkage between the murine major transplantation (H2) antigen complex and relative resistance to virus induced leukemogenesis in mice provided the original stimulus for the search for an association between HLA and specific disease susceptibility in man.15 In mice it was shown subsequently that specific immune response (Ir) genes linked to the major histocompatibility complex (MHC) control the immune responsiveness to a number of polypeptide or protein antigens.15 In man, the MHC is located on chromosome six,17 and contains the genes for a variety of functions including lymphocyte dependent and mixed lymphocyte culture cell surface determinants.24 Human equivalents to the murine Ir genes have not yet been mapped precisely15 but are thought to locate close to the MHC. In fact, several functions which have been mapped to the I region of the mouse have been localized to HLA-D.16 For excellent introductions to the subject of HLA and disease see Svejgaard24 and Dausset.1 Various hypotheses have been offered to explain the association of HLA and certain diseases.15 To date, the experimental evidence is insufficient to choose between these (or other) alternatives. However, to judge from the mouse model system, HLA antigens and the closely linked Ir genes may play an important role in genetic susceptibility or resistance to carcinogenesis, infection, and autoimmunity.15 In this chapter we review the reported associations between psoriasis and the MHC: (1) in Caucasian populations and in Orientals; (2) in the various clinical subtypes of psoriasis, and (3) in psoriasis vulgaris when it is associated with seronegative polyarthritis. Existing evidence on the relationship of age of onset and HLA is documented, as are the conflicting reports of infection-exacerbated psoriasis and HLA. Finally, we discuss the relevance of the HLA data in understanding the psoriatic disease process. IL H LA ASSOCIATED W ITH PSORIASIS IN DIFFERENT RACES Psoriasis, a skin disease characterized by epidermal hyperproliferation,25 is transmitted in a pattern most consistent with a dominant mode of inheritance with multifactorial influence of phenotypic expression.12 Although the association between HLA and psoriasis is by no means absolute, HLA provides the only readily accessible genetic marker for this disease at the present time. A. HLA Associated with Psoriasis in Caucasian Populations In 1972, Russell et al.21 and White et al.26 reported that the frequency of the HLA distribution in psoriatic patients differs from that in control populations. Subsequently, Krulig et al.12 confirmed the association of BW-17 and psoriasis and identified a new antigen BW-16 which was present in 22% of the patients vis-à-vis 5% in controls. These investigators could not demonstrate an increased frequency of B-13 in psoriatic patients. However, in Scandinavian populations, the association between HLA-B13 and psoriasis was confirmed.823 More recently another antigen of the B series HLABW-37 was found to be increased in patients with psoriasis vulgaris.828 No strong

17 Table 1 THE FREQUENCY OF HLA ANTIGENS ASSOCIATED WITH PSORIASIS Antigen Frequency (°/o) Disease Psoriasis vulgaris

Pustular psoriasis

Racial Group

HLA Type

Caucasian

B13

Japanese Caucasian

B13 BW17 BW17 BW37 BW37 C6 DW 11 BW37 B27 B27

Patients

Controls

Relative risk

Ref.

2

2

1.2

14a

21 12 36 4 6 84 42 16 13

2.8 5 8 3 1 35 5 0.8 8

9.0 2.5 6.5 1.4 6.6

1.9

23 1 23 1 8 18 18 19 23

56

14

7.6

8

10.4

Data not available.

association between psoriasis and an HLA antigen of the A series has been found.12 This suggests that the disease susceptibility gene(s) for psoriasis may map closer to the HLA-B locus. As can be seen from Table 1, however, the association between psoriasis and antigens of the B series varies considerably ranging from a relative risk of 1.2 to 9.0. Recently two other HLA loci, HLA-C and D, have been defined. A striking association exists between psoriasis and C6 and DW11 locus products.18 This single report of a relatively small series shows that DW11 is significantly increased in patients with psoriasis with a relative risk of 10.4 and X2 of 27.6. B. HLA Associated with Psoriasis in Non-Caucasian Populations In an Oriental population no association was found between psoriasis and HLAB13, BW16, or BW17. Instead the antigens HLA-A1 and BW37 were increased (the latter with an X2 of 41.1) compared to healthy controls.19 Interestingly, the American Indian as well as the West African Negro have a very low incidence of psoriasis.13 Moreover, in the American Indian control population the frequency of HLA-B 13 is 0% and HLA-BW17 is only 1%. However, although the West African Negro has a low frequency of HLA-B13 (about 1%), the frequency of BW-17 in the control population ranges between 15 and 50%.13 C. Family Studies in Caucasians and Orientals To date family studies in Caucasians have not been conclusive. In one series B13 was present in four families10 while the presence of BW-37 plus other genetic factors favored the development of psoriasis in other families.9 In another report, BW-37 also was found in family members affected with psoriasis, but not all the members with BW37 had the disease.14 In a family study where psoriasis occurred in three generations all affected members had the BW17 antigen, whereas, absence of this antigen coincided with lack of disease.12 Similarly, Woodrow27 found that if BW17 were present it was seen in all those family members with disease expression but that BW17 was not found in all the families studied. In family studies of Orientals insufficient data are available to determine the degree of segregation.19

18

Autoimmunity in Psoriasis

D. Significance of Studying HLA in Different Races Since psoriasis associates with HLA B, C, and D locus products and since the association though significant is not extremely strong, it is likely that psoriasis is not associated with a specific HLA allele itself but rather to a disease susceptibility gene or genes that maps in the region of the MHC. Examination of the association of psoriasis in different races supports this conclusion since one would not expect the same HLA alleles to be associated with psoriasis in different races if HLA were only a marker for a linked disease susceptibility gene. III. SEGREGATION OF HLA W ITH CLINICAL FEATURES OF PSORIASIS A. Age of Onset and Severity of the Disease Krulig et al.12 reported that patients with HLA-BW17 tended to have an earlier age of onset compared to those patients with HLA-BW16. Furthermore, those patients who demonstrated BW16 and/or BW17 had more severe disease involvement than those patients who had neither of these antigens. B. Relationship of HLA to Infection Exacerbated Psoriasis The evidence regarding HLA and infection precipitated psoriasis is not uniform. Karvonen8 reported that a clear association exists between HLA-B13 and psoriatic exacerbations following respiratory tract infections. On the other hand, two authors reported no characteristic HLA pattern in those patients who had episodes of psoriasis following /I-hemolytic streptococcal infections.2123 C. HLA in Pustular Psoriasis In a study of HLA antigens in patients with pustular psoriasis, the HLA antigen distribution was found to be different than that seen in psoriasis vulgaris.23 28 In particular, generalized pustular psoriasis does not have increased B13 or BW17, but rather shows an increased frequency of BW27. Furthermore, localized psoriasis of palms and soles, and acrodermatitis continua show the same HLA pattern as generalized pustular psoriasis but not that seen in psoriasis vulgaris.28 Finally, BW35 was found to be elevated in persistent palmo-plantar pustulosis, but not in the other types of pustular psoriasis or psoriasis vulgaris.728 D. Psoriasis and Seronegative Polyarthritis The data on the association of psoriatic arthritis and HLA antigens at the B locus is confusing. Early studies showed an increased frequency of HLA-BW27 in psoriatic patients with arthritis.823 In a study of 60 patients with psoriatic arthritis the frequency of HLA-B13 and BW17 was increased in both patients with psoriasis and psoriatic arthritis when compared to controls.6 However, these two antigens were not more prevalent in the subpopulation of arthritis patients who had signs of spondylitis. In this subgroup, only HLA-B27 was strongly increased (47 vs. 12% in controls). Another report indicates that HLA-BW38 is increased in patients with peripheral arthritis but not in patients who have psoriatic spondylitis or only skin lesions.2 On the other hand, Feldman et al.4 found BW38 increased in patients with peripheral and axial joint involvement. Finally, in a large series B27 and BW38 were strongly associated with central psoriatic arthritis, whereas, peripheral arthritis had the same frequency of association to HLA-B markers as did psoriasis of the skin.20

19 IV. TH E SIGNIFICANCE OF THE HLA DATA A. HLA as a Genetic Market to Separate Clinical Subgroups The finding of disease associated genetic markers in a large number but not all of the psoriatic patients may mean that the disease is in weak linkage disequilibrium with HLA. Alternatively, it could mean that different subgroups of the disease exist.5 Indeed, the evidence on the frequency of B-locus antigens in psoriasis vulgaris and the different forms of pustular psoriasis would support this argument. It may be that typing for antigens of the D and C series in psoriatic patients will lead, in the near future, to the delineation of distinct clinical subgroups of the disease. This could be significant in terms of prognosis, response to therapy, and genetic counseling. B. HLA May Give Clues to the Etiology of Psoriasis The fact that psoriasis is associated with HLA B, C, and D locus antigens can be explained in several ways. First, it may be that these antigens are in linkage disequilibrium with a psoriatic disease susceptibility gene or genes which when activated by environmental triggers lead to epidermal hyperproliferation. Secondly, the HLA antigens may serve as receptors5 for an infectious agent such as a virus.3 Finally, these HLA antigens could cross react with surface antigens of a pathogenic agent conferring tolerance to the pathogen with resultant disease manifestations.5 Recent evidence that psoriatic patients show a defect in their cell mediated immunity would seem to support the third alternative (see Chapters 13 and 18).

REFERENCES 1. Dausset, J. and Svejgaard, A ., Eds., H LA and Disease, Williams & Wilkins, Baltimore, 1977. 2. Espinoza, L. R., Vasey, F. B., Oh, J. H ., Wilkinson, R., and Osterland, C. K., Association between HLA-BW38 and peripheral psoriatic arthritis, Arthr. Rheum., 21,72, 1978. 3. Färber, E. M ., Nall, M. L., Morhenn, V., and Kaye, J., Introduction: unanswered questions about psoriasis, in Psoriasis: Proc. and Int. Sym p., Färber, E. M. and Cox, A. J., Eds., Yorke Medical Books, New York, 1977, 27. 4. Feldmann, J. L., Amor, B., Cazalis, P ., Dryll, A ., Hors, J., and Hacquart, B., Antigènes HLA chez les malades atteints de rhumatisme psoriasique, Nouv. Presse M ed., 5, 477, 1976. 5. Grumet, F. C., Tissue antigens in psoriasis, in Psoriasis: Proc. 2nd Int. Sym p., Färber, E. M. and Cox, A. J., Eds., Yorke Medical Books, New York, 1977, 134. 6. Jajic, I., KaStelan, A ., Brnobic, A ., Kerhin, V., and Brklja£ic, L., HLA antigens in psoriatic arthritis and psoriasis, Arch. Derm atol., 113, 1724, 1977. 7. Karvonen, J., Tiilikainen, A ., and Lassus, A ., HL-A antigens in patients with persistent palmoplantar pustulosis and pustular psoriasis, Ann. Clin. Res., 7, 112, 1975. 8. Karvonen, J., HL-A antigens in psoriasis with special reference to the clinical type, age of onset, exacerbations after respiratory infections and occurrence of arthritis, Ann. Clin. Res., 1, 301, 1975. 9. Karvonen, J., Tiilikainen, A ., and Lassus, A ., HLA antigens in psoriasis. A family study, Ann. Clin. Res., 8,298, 1976. 10. Karvonen, J., Tiilikainen, A ., and Lassus, A ., HLA antigens in psoriasis, in Psoriasis: Proc. 2nd Int. Sym p., Färber, E. M. and Cox, A. J., Eds., Yorke Medical Books, New York, 1977, 405. 11. Krain, L. A ., Histocompatibility antigens: a laboratory and epidemiologic tool, J. Invest. Dermatol., 62, 67, 1974. 12. Krulig, L., Färber, E. M ., Grumet, C., and Payne, R. O., Histocompatibility (HL-A) antigens in psoriasis, Arch. Derm atol., I l l , 857, 1975. 13. Lobitz, W. C., Civatte, J., Thivolet, J., Betuel, H ., and Thorsby, E., Dermatology, in H LA and Disease, Dausset, J. and Svejaard, A ., Eds., Williams & Wilkins, Baltimore, 1977, 126.

20

Autoimmunity in Psoriasis

14. Marcusson, J., Möller, E., and Thyresson, N., Penetration of HLA-linked psoriasis-predisposing gene(s): a family investigation, Acta Dermatovener Stockholm, 56, 453, 1976. 14a. Marcusson, J., Acta Derm atovener Stockholm, 55, 297, 1975. 15. McDevitt, H. O. and Bodmer, W. F., HL-A, immune-response genes, and disease, Lancet, 1, 1269,

1974. 16. McDevitt, H. O. and Engleman, E. G ., Association between genes in the major histocompatibility complex and disease susceptibility, Arthr. Rheum.,20, S9, 1977. 17. McKusick, V. A ., Mendelian Inheritance in Man, The Johns Hopkins University Press, Baltimore, 1976, 60. 18. McMichael, A. J., Morhenn, V ., Payne, R., Sasazuki, T ., and Färber, E. M., HLA C and D antigens associated with psoriasis, Br. J. D erm atol.,98, 287, 1978. 19. Ohkido, M., Ozawa, A., Matsuo, I., Niizuma, K., Nakano, M., Sugai, T., Tsuji, K., Nose, Y., Ito, M., and Yasuda, T., HLA antigens and susceptibility to psoriasis vulgaris in a Japanese population, in Psoriasis: Proc. 2nd Int. Sym p., Färber, E. M. and Cox, A. J., Eds., Yorke Medical Books, New York, 1977, 402. 20. Roux, H., Mercier, P., Maestracci, D., Serratrice, J., Sany, J., Seignalet, J., and Serre, H., Psoriatic arthritis and HLA antigens, J. Rheumatol., 3, 64, 1977. 21. Russell, T. J., Schultes, L. M., and Kuban, D. J., Histocompatibility (HL-A) antigens associated with psoriasis, N. Engl. J. Med., 287, 738, 1972. 22. Ryder, L. P. and Svejgaard, A., Associations between HLA and disease, Compactas, Copenhagen: Registry o f Copenhagen, 1976. 23. Svejgaard, A., Nielsen, L. S., Svejgaard, E., Nielsen, F. K., Hjortsh^j, A., and Zachariae, H., HLA in psoriasis vulgaris and in pustular psoriasis — population and family studies, Br. J. Dermatol., 91, 145, 1974. 24. Svejgaard, A., Platz, P., Ryder, L. P., Nielsen, L. S., and Thomsen, M., HL-A and disease associations — a survey, Transplant. Rev., 22, 3, 1975. 25. Weinstein, G. D. and Frost, P., Abnormal cell proliferation in psoriasis, J. Invest. Dermatol., 50, 254, 1968. 26. White, S. H., Newcomer, V. D., Mickey, M. R., and Terasaki, P. L, Disturbance of HL-A antigen frequency in psoriasis, N. Engl. J. M ed., 287, 740, 1972. 27. Woodrow, J. C., Dave, V. K., Usher, N., and Anderson, J., The HL-A system and psoriasis, Br. J. D erm atol., 92, 427, 1975. 28. Zachariae, H., Petersen, H. O., Nielsen, F. K. and Lamm, L., HL-A antigens in pustular psoriasis, Dermatologica, 154, 73, 1977.

21

Chapter 3 HISTOLOGY OF PSORIASIS: THE ROLE OF POLYM ORPHONUCLEAR NEUTROPHILES* Stefania Jab/onska, Olena Chowaniec, and Ewa Maciejowska TABLE OF CONTENTS I.

Introduction, Histopathologic Changes in Psoriasis........................................ 22 A. Zones of Histopathologic Changes in Psoriasis.....................................22 B. Proliferative Changes and Pinpoint Lesions of Psoriasis......................22

II.

History of Typical Spontaneous Psoriatic Lesions.............................................23 A. Histologic Features of Fully Developed Psoriatic Lesions......................23 B. Squirting Papilla.......................................................................................23

III.

Initial Histologic Changes in Provoked Lesions in Psoriatics........................... 24 A. Histologic Features of the Scratch-Provoked Koebner phenomenon.. .24 B. Histologic Features of Lesions Provoked by Stripping......................... 25

IV.

Histologic Changes that Precede the Appearance of Spontaneous Psoriatic Lesions............................................................................................................... 27 A. Histologic Features of Prepinpoint Papules...........................................27 B. Histologic Features of the Uninvolved Skin of Psoriatic P atien ts........31

V.

Summary and Conclusions................................................................................ 34 A. Summary.................................................................................................. 34 B. Conclusions.............................................................................................. 35

References....................................................................................................................... 36

*

This work was supported by grant #10.5.07.2.1 of the Polish Academy of Sciences.

22

A utoimm unity in Psoriasis

I. INTRODUCTION, H ISTOPA TH OLOG IC CHANGES IN PSORIASIS Fully developed psoriatic plaque shows characteristic changes in the epidermis and dermis. In the epidermis there is parakeratosis, partial or complete atrophy of the granular layer, elongation and thickening of the rete pegs (acathosis and papillomatosis) with considerable thinning of the stratum Malpighi over the elongated dermal papillae (Figure 1). The upper part of the papillae is edematous and round-cell inflammatory infiltrates are present around the dilated capillaries.5 The infiltrates consist chiefly of lymphocytes and mononuclear cells. While the old argument over whether the primary lesions are in the epidermis or the corium remains unsettled, the proliferative processes in the epidermis are very much in the foreground, so that psoriasis is regarded as a benign proliferative disease of the epidermis. A. Zones of Histopathologic Changes in Psoriasis Braun-Falco’s studies of psoriatic plaques a few centimeters in size have shown a range of histologic changes throughout the area.23 The author distinguished four zones. The first extended over the unchanged skin bordering directly upon the plaque and the fourth occupied the central part of the lesion. Close to the lesions the epidermis was slightly thicker, the stratum corneum orthokeratotic, and the nuclei in the granular layer were slightly pyknotic. Histochemical methods, however, demonstrated phospholipids, hydrolytic enzymes, and some dehydrogenases in the transitional zone of the stratum corneum, i.e., that directly overlying the granular layer, and this was described as “ histochemical parakeratosis” .* In the second zone the thickened epidermis showed hyperkeratosis, hypergranulosis and “ histochemical parakeratosis” with focal presence of nuclei in the stratum corneum. In the third, more central, zone proliferation of the epidermis was distinct, with atrophy of the stratum granulosum, focal parakeratosis, and exocytosis with occasional clusters of polymorphonuclear leucocytes in the horny layer. In all three of these zones the corium contained macrophage, lymphocyte, and mast cell infiltrates, increasingly profuse towards the center of the lesion, with neutrophils and more pronounced vascular changes appearing in the third. In the fourth, central, zone the changes were characteristic of psoriasis both in the epidermis and dermis with infiltrates containing numerous polymorphonuclear leucocytes penetrating through the tips of the papillae into the epidermis and forming Munroe microabscesses in the stratum corneum. B. Proliferative Changes and Pinpoint Lesions of Psoriasis Proliferation of the epidermis has been demonstrated in psoriasis by a variety of methods, most notably by autoradiography.1617 While in vivo studies have shown the epidermal cell cycle to be shortened to about one eighth in psoriasis,1617 in vitro studies have failed to indicate any significant increase in the proliferative capacity of psoriatic epidermal cells when investigated without the underlying dermis, i.e., without influx of white blood cells.7 The results obtained by various authors vary considerably, probably depending chiefly on the stage of development and activity of the lesions investigated10 11 and perhaps also on diurnal variation.15 Investigation of the earliest lesions barely a few millimeters in diameter and referred to as pinpoint papules has shown a particularly intensive change in the corium which sometimes even constituted the most prominent feature.4 The infiltrates were made up of lymphocytes and macrophages with neutrophils present near vessels in only 4 of the

*

Editor’s note: see also Chapter 13.

23

FIGURE 1.

Histology of a typical psoriatic plaque.

31 biopsies examined.5 It is worth stressing that the epidermis was only slightly thicker over the most pronounced infiltrates showing also atrophied granular layer and parakeratosis.4 Despite distinct exocytosis, Munro microabscesses were rare in pinpoint lesions since it was chiefly macrophages and lymphocytes that penetrated into the epidermis and constituted the principal components of perivascular infiltrations. After cytochemical investigations of 2- to 3-weeks-old pinpoint papules Braun-Falco and Schmoeckel6 confirmed the presence in infiltrations of the corium chiefly of macrophages and monocytes and partly also lymphocytes as well as the penetration of lymphocytes and macrophages into the epidermis. Neutrophils were scanty and were seen only where proliferation of the epidermis was pronounced, i.e., in long standing lesions. The authors felt that the histology of early psoriatic papules implicates delayed hypersensitivity as was postulated by Cormane et al.9 II. HISTOLOGY OF TYPICAL SPONTANEOUS PSORIATIC LESIONS A. Histologic Features of Fully Developed Psoriatic Lesions Our histological studies of 138 cases of well-developed psoriatic lesions confirmed the presence of lymphocytes, monocytes, and macrophages as the chief elements of perivascular infiltrations. However, in many peripherally spreading lesions clusters of neurophils occurred in the epidermis and in all active lesions exocytosis and “ squirting papilla” with penetration of neutrophils into the epidermis were present (Figure 1). B. Squirting Papilla Munro abscesses are a very characteristic feature of well-developed psoriasis plaques. However, their mechanism of formation had until recently remained completely obscure (see Chapter 8). The accumulation of leukocytes results from migration of inflammatory cells, mainly polymorphs, but also lymphocytes through the elongated dermal papillae into the overlying epidermis (Figure 2). Pinkus and Mehregan13 referred to this sequence of changes as “ squirting papilla” .

24

Autoimmunity in Psoriasis

FIGURE 2. Accumulations of polymorphs in the horny layer (Munro microabscesses) and chiefly polymorphonuclear roundcell infiltrates penetrating into the suprapapillary part of the epidermis.

III. IN ITIAL H ISTOLOG IC CHANGES IN PROVOKED LESIONS IN PSORIATICS A. Histologic Features of the Scratch-Provoked Koebner Phenomenon To investigate the earliest abnormalities we examined the histology of scratch-provoked psoriatic lesions, i.e., the Koebner phenomenon, in 198 cases of psoriasis (88 active and 110 stationary ones) and 39 controls. As little as 4 hr after scarification there were agglomerations of polymorphonuclear leucocytes in perivascular infiltrates and in the epidermis (Figures 3A and 3B). Initially in the first 3 to 4 days the infiltrates were alike in psoriatic patients and in the controls (Figure 4) but subsequently became more pronounced in patients with a positive Koebner reaction.12 In the controls and in psoriatic patients who failed to develop the Koebner phenomenon the scarification crust dropped off after about 4 days and the site healed completely. Between the 5th and 10th to 14th day, i.e., before the appearance of the psoriatic lesion, examination revealed inflammatory infiltrates with numerous polymorphonuclear leucocytes which already had entered the epidermis and formed agglomeration (Figure 5); at this time no psoriatic changes were in evidence. In cases in which a positive Koebner phenomenon developed, a massive penetration of polymorphs into the epidermis resulted in

25

A

B FIGURE 3. Patient with psoriasis. Previously uninvolved skin 24 hr after scratch. Accumulation of polymorphs at the scratched site. In and about vessel walls chiefly polymorphonuclear inflammatory infiltrates with prominent leukocytoclasia, but little or no acanthosis. [(A) Magnification x 90.] [(B) Magnification x 240.]

destruction of the basal cell layer and a progressive development of the histologic features characteristic of psoriasis. B. Histologic Features of Lesions Provoked by Stripping To investigate the role of minor traumas in the development of psoriatic plaques we examined the histology of lesions induced by a superficial incomplete stripping. Thirty to forty strippings were performed in an area of 2 cm by 8 cm on the arm in

26

Autoimmunity in Psoriasis

FIGURE 4. Patient with psoriasis. Five days after scratch. Polymorphs penetrating into the epidermis near the scratched site. (Magnification x 240.)

FIGURE 5. Patient with psoriasis. Eight days after scratch. Transitional stage between prepinpoint papule (ppp) and psoriasis. No clinical signs of psoriasis. Pronounced round-cell infiltrations with numerous polymorphs under the edematous and partly destroyed epidermis and/or penetrating it. Atrophy of the granular layer and absence o f noticeable parakeratosis or acanthosis. (Magnification x 240.)

27

FIGURE 6. Patient with psoriasis. An early prepinpoint papule that developed 6 hr after partial stripping. Around small vessels inflammatory infiltrates with abundant polymorphs. Edema of the epidermis, exocytosis, and some parakeratotic cells in the stratum corneum. (Magnification x 240.)

each of 30 patients (21 with active and 9 with stationary psoriasis). Ten developed very fine papules in 6 to 96 hr, still without the characteristics of psoriasis. When examined 6 hr, 24 hr, 48 hr, and 96 hr after stripping, the histology showed edema of the epidermis where the stratum corneum failed to be removed. Already after 2 hr there was evidence of the diapedesis of polymorphonuclear leucocytes from the perivascular infiltrates into the epidermis (Figure 6). Both infiltration and exocytosis, were much more pronounced after 48 and 96 hr (Figure 7A). Where the stratum corneum and the stratum granulosum both had been fully detached, parakeratosis was distinct even when the epidermis was markedly thinned (Figure 7B); this seems to support the view that parakeratosis is independent of an increase in the mitotic activity of the epidermis.8 Thus, also in the papules that precede the development of psoriatic plaques, there were numerous polymorphonuclear cells in the inflammatory infiltrates. In our studies we failed to induce psoriatic lesions throughout the area subjected to stripping, as reported by Reinertson,14 who removed the horny and the granular layer and thus produced weeping. Fourteen days after stripping, a small papule that had developed was found to have a histology fully typical of psoriasis (Figure 8); this shows that the early small papules formed at the site of incomplete stripping are representative of the initial stages in the development of psoriatic lesions. IV. H ISTOLOG IC CHANGES TH A T PRECEDE THE A PPEARA N CE OF SPONTANEOUS PSORIATIC LESIONS A. Histologic Features of Prepinpoint Papules Infiltrates consisting of numerous polymorphonuclear leucocytes and patterns corresponding to those observed after partial stripping were seen in the earliest spontaneously developing lesions.* We refer to these as prepinpoint papules because they Editor’s note: see also Chapter 13 for discussion of early histologic changes. The difference may be due to the nature of the materials examined.

28

Autoimmunity in Psoriasis

A

B FIGURE 7. (A) A papule that developed 96 hr after stripping. Pronounced round-cell infiltrates, with predominance o f polymorphs, under the thinned epidermis and around hair follicles. (Magnification x 90.) (B) A part of 7A. Inflammatory infiltrates with numerous polymorphs. Epidermis atrophic and partly destroyed, composed of two or three layers of swollen cells. Granular layer atrophic. In some areas of the horny layer parakeratotic and inflammatory cells. (Magnification x 240.)

29

FIGURE 8. Fourteen-day old papule that developed 24 hr after stripping. Histology typical of pinpoint lesions with acanthosis, atrophic granular layer, and parakeratosis. (Magnification x 240.)

have none of the clinical and histological features of psoriasis. The investigations were made in 40 patients. Each had a skin area of 10 cm by 10 cm marked out on the arm and the lesions appearing within it but bearing none of the characteristics of psoriasis were marked with a felt pen and watched 14 days. Ten healthy subjects served as controls. Very small (about 0.5 mm) erythematous and very flat papules, almost flush with the skin and showing no signs of scaling, developed within the squares in 25 of the 40 patients (in 22 with active and in 3 with inactive psoriasis). In 5 to 8 days a majority of the prepinpoint papules developed into pinpoint papules in all the 22 patients with active psoriasis and in one of the three inactive cases. The typical pinpoint papules were recognized when parakeratotic scaling appeared or could be evoked by gentle scraping. Histological examination revealed extensive infiltrations made up in large part of polymorphs, chiefly around the dilated capillaries of the upper corium and penetrating into the epidermis (Figure 9). The epidermis was edematous at the site of exocytosis and in some of the cases the granular layer was atrophied without parakeratosis and other epidermal changes characteristic of psoriasis (Figure 10). Sometimes the infiltrates surrounded the appendages, hair follicles, or sweat ducts (Figure 11).

30

A utoimm unity in Psoriasis

FIGURE 9. Lesion preceding the pinpoint papule (prepinpoint papule). No clinical features of psoriasis. Pronounced lymphocytic and polymorphonuclear infiltrates in the upper corium. Exocytosis. Epidermis hypertrophic and edematous, with granular layer partly preserved and orthokeratosis. (Magnification x 240.)

FIGURE 10. Lesion preceding the pinpoint papule (prepinpoint papule). No clinical features of psoriasis. Massive penetration o f mainly polymorphonuclear infiltrates into the epidermis with partial destruction of the latter, edema and proliferation at the periphery. Granular layer atrophic. Accumulations of polymorphonuclears in the orthokeratotic stratum corneum. (Magnification x 240.)

With infiltrates penetrating into the epidermis, the histologic picture became similar to that of early pinpoint papules, especially when both mononuclear cells and polymorphs were numerous or when serial sections showed some focal parakeratosis.

31

FIGURE 11. Prepinpoint papule. Heavy, chiefly polymorphonuclear, infiltrates surrounding blood vessels and a sweat duct and penetrating into the partly destroyed epidermis; granular layer atrophic. This is an early transition into the pinpoint papule. (Magnification x 240.)

The histologic similarities in and differences between prepinpoint and pinpoint lesions are presented in Table 1. The most distinctive feature of prepinpoint papules was predominantly polymorphonuclear perivascular infiltrates penetrating heavily into the epidermis, as contrasted with the predominance of lymphocytes and macrophages in pinpoint papules.4,5 In contrast to the pinpoint papules there was no epidermal proliferation, atrophy of the granular layer, and parakeratosis. Worth stressing is the close histological similarity between the minute papules developing 6 to 96 hr after incomplete stripping and the spontaneous prepinpoint papules which seem to point to subtle traumas as a factor inducing psoriatic lesions. B. Histologic Features of the Uninvolved Skin of Psoriatic Patients In the uninvolved skin some 4 to 5 cm away from the lesions we found inflammatory infiltrates composed of polymorphs and mononuclear cells (Figure 12). In infiltrates adhering to and penetrating into the epidermis (exocytosis) or surrounding the skin appendages and in the more extensive infiltrates the predominant component was pol-

32

Autoimmunity in Psoriasis Table 1 HISTOLOGIC FEATURES OF THE PREPINPOINT PAPULES VS. THOSE OF THE PINPOINT TYPE Histologic features

Prepinpoint papules

Pinpoint papules

Infiltrates around blood vessels Abundant or predominant polymorphs in the infiltrates Inflammatory infiltrates beneath the epidermis, mainly around the appendages Exocytosis Edema of the epidermis at the site of exocytosis Acanthosis and papillomatosis Stratum granulosum atrophied Stratum corneum Orthokeratosis Parakeratosis Accumulations of polymorphs in the horny layer

25/25 21/25 16/25

10/10 0/10 3/10*

24/25 24/25 0/25 16/25

10/10 8/10 7/10 8/10

° *

4/25* 6/25

Psoriatic changes at the site of appendages. In small foci, very slight.

FIGURE 12. Uninvolved skin. Stationary psoriasis. Inflammatory infiltrates with numerous polymorphs around blood vessels. Slight exocytosis. Epidermis unchanged. (Magnification x 240.)

9/10 3/10

33

FIGURE 13. Uninvolved skin. Stationary psoriasis. Roundcell infiltrates around hair follicles and sebaceous glands. (Magnification x 90.)

ymorphonuclear leucocytes (Figures 13 and 14). In some of the specimens (8 of 25 from active cases and 6 of 18 from the stationary) there was some exocytosis. A characteristic feature was the inflammatory cell infiltrate with numerous polymorphonuclear leucocytes around the skin appendages. We found this in 19 of 25 biopsies from active cases and 14 of 18 from the stationary (Figure 15). Braun-Falco,4 on the other hand, found in the uninvolved skin of psoriatic patients only minor perivascular infiltration chiefly by macrophages, lymphocytes and mast cells. The differences are probably determined by the choice of cases and skin areas (in his cases the biopsied normal skin was surrounded by psoriatic plaques only 2 to 4 cm away) and above all, by the depth of biopsy and preparation of serial sections. The polymorphonuclear infiltrates have a patchy distribution and can be demonstrated reliably only in serial sections. In many cases we found them only deeper in the corium, in the neighborhood of the appendages, notably sweat glands and hair follicles. It is conceivable that the infiltrates around skin appendages depend on the bacterial flora of the skin surface, e.g., Staphylococcus aureus, which is more profuse in psoriasis than in healthy subjects.1 Microtraumas that do not give rise to noticeable changes also seem to play a part since the pictures seen in the uninvolved skin of patients with psoriasis and in patients with negative Koebner phenomenon after stripping are quite similar.

34

Autoimmunity in Psoriasis

FIGURE 14. The same specimen as in Figure 13 at higher magnification. Chiefly polymorphonuclear infiltrates. (Magnification x 240.)

V. SUMMARY AND CONCLUSIONS A. Summary Histologic studies of well developed psoriatic lesions performed in 138 patients with variously active disease revealed polymorphic but predominantly mononuclear infiltrates and the presence of polymorphonuclear leucocytes in squirting papillae and Munro abscesses in the stratum corneum of hyperproliferative epidermis. These findings are consistent with those reported by Braun-Falco,36 Pinkus and Mehregan,13 Ragaz and Ackerman,13“ and others. Histologic studies of the changes which precede the fully developed psoriatic lesions, provoked by scratching in 198 cases of psoriasis and 39 controls and by stripping in 30 cases of psoriasis and 10 controls, showed numerous polymorphonuclear neutrophils in infiltrates surrounding dilated blood vessels and appendages and penetrating into the epidermis. Exocytosis seems to be the basic phenomenon both in controls and in cases of psoriasis up to 4 to 5 days after scratching. Thereafter the same type of predominantly neutrophilic infiltrates became more pronounced in patients with a positive Koebner reaction while the crusts dropped off and healing occurred in controls and patients with negative Kôebner reactions. Similarly, the earliest prepsoriatic pa-

35

FIGURE 15. Uninvolved skin. Heavy infiltrate containing numerous polymorphonuclears and surrounding a sweat duct. Epidermis unchanged. (Magnification x 240.)

pules provoked in 1 to 4 days by 30 to 40 strippings in 30 psoriatic patients showed predominantly polymorphonuclear leucocyte infiltrates around vessels, epidermal appendages, and in the epidermis. Similar infiltrates with very numerous polymorphonuclear leucocytes occurred in 25 patients with spontaneous prepinpoint lesions, the earliest clinically demonstrable lesions which later developed into typical pinpoint lesions but which at the time of examination had none of the clinical or histologic features of psoriasis. The cellular infiltrates in these 25 “ prepinpoint” lesions differed from those of ten typical pinpoint lesions in the predominance of polymorphonuclear leucocytes. In contrast, in pinpoint lesions and in the fully developed psoriatic plaques the infiltrates consisted chiefly of lymphocytes, while neutrophils were the main component of squirting papillae and especially of Munro microabscesses. B. Conclusions The early histologic changes that precede the development of psoriasis both in lesions provoked by scratching or stripping and in spontaneous lesions are qualitatively comparable to those induced by skin trauma in normal subjects but are quantitatively greater and more long lasting than the latter. These histologic features are comparable to immunopathologic findings on stratum corneum antibody binding at sites of trauma of normal and psoriasis prone subjects, i.e., similar but more extensive binding of stratum corneum antibodies occurs prior to the development of psoriatic lesions. Studies of earliest changes that precede the development of typical psoriatic lesions point to an initiating role of polymorphonuclear neutrophils; the available evidence suggests that these are attracted by the formation of stratum corneum antigen, antibody, complement complexes in the horny layer in the Kóebner reactions induced by scratching. Histologic and immunofluorescence studies of responses of psoriatic patients to stripping in contrast suggest that polymorphonuclear leucocytes are attracted to prepinpoint papules by nonimmunologic mechanisms; these may of themselves induce the in vivo reactions of the stratum corneum antibodies seen at the time of transition to psoriatic “ pinpoint papules” . Data relevant to the possible role of hydrolytic enzymes

36

Autoimmunity in Psoriasis

of polymorphonuclear leucocytes, most notably the serine proteases, are presented in Chapter 16.

REFERENCES 1. Aly, R., Mai bach, H. I., and Mandel, A., Bacterial flora in psoriasis, Br. J. Derm atol. , 95 (6), 603, 1976. 2. Braun-Falco, O., Zur Morphogenese der psoriatischen Hautreaktion, Arch. Klin. Exp. Derm., 217, 130,1963. 3. Braun-Falco, O., Dynamics o f growth and regression in psoriatic lesions; alterations in the skin from normal into a psoriatic lesion, and during regression of psoriatic lesions, in Psoriasis. Proc. Int. Sym p., Stanford University, 1971, Färber E. M. and Cox, E. J., Eds., Stanford University Press, California, 1971,215. 4. Braun-Falco, O., The initial psoriatic lesion, in Psoriasis. Proc. 2nd Int. Sym p., Stanford, 1976, Färber, E. M. and Cox, A. J., Eds., Yorke Medical Books, New York, 1977, 1. 5. Braun-Falco, O. and Christophers, E., Structural aspects of initial psoriatic lesions, Arch. Dermatol. Fasch.,251, 95, 1974. 6. Braun-Falco, O. and Schmoeckel, Ch., The dermal inflammatory reaction in initial psoriatic lesions, Arch. Dermatol. Res., 258, 9, 1977. 7. Chopra, D. P. and Flaxman, B. A ., Comparative proliferative kinetics of cells from normal human epidermis and benign epidermal hyperplasia (psoriasis) in vitro, Cell Tissue Kinet, 7, 69, 1974. 8. Christophers, E. and Braun-Falco, O., Mechanisms of parakeratosis, Br. J. Dermatol., 82, 268,1970. 9. Cormane, R. H., Hungadi, J., and Hamerlinck, F., The role of lymphoid cells and polymorphonuclear leukocytes in the pathogenesis of psoriasis, J. Derm atol., 3, 247, 1976. 10. Gelfant, S., The cell cycle in psoriasis: a reappraisal, Br. J. Derm atol., 95, 577, 1976. 11 . Goodwin, P., Hamilton, S., and Fry, L., The cell cycle in psoriasis, Br. J. Derm atol.,90, 517, 1974.

12. JatyTonska, S., Beutner, E.H., Jarzabek-Chorzelska, M., Maciejowska, E., Rzesa, G., Chowaniec, O., and Chorzelski, T. P., Clinical significance of autoimmunity in psoriasis, in Immunopathology. Proc. 6th Int. Convocation Immunology, Milgrom, F. and Albini, B., Eds., S. Karger, Basel, 1979, 148. 13. Pinkus, H. and Mehregan, A. H., The primary histologic lesion of seborrheic dermatitis and psoriasis, J. Invest. D erm atol. ,46, 109, 1966. 13a. Ragaz, A. and Ackerman, A. B., Evolution, maturation, and regression of lesions of psoriasis, Am .

J. Derm atopathol., 1, 199, 1979. 14. Reinertson, R. P., Vascular trauma and the pathogenesis of the Koebner reaction in psoriasis, J. Invest. D erm atol.,30, 283, 1958. 15. Rowe, L ., Dixon, W. J., and Forsythe, A ., Mitoses in normal and psoriatic epidermis, Br. J. Derm atol., 98, 293,1978. 16. Weinstein, G. D. and Frost, P., Cell proliferation kinetics in benign and malignant skin diseases in humans, Nat. Cancer Inst. M on ogr.,30 , 373, 1963. 17. Weinstein, G. D. and Frost, P., Abnormal cell proliferation in psoriasis, J. Invest. Dermatol., 50, 254, 1968.

Part II: Humoral Immune Responses in Psoriasis

39 Chapter 4 STRATUM CORNEUM ANTIGENS AND ANTIBODIES AS REVEALED BY IM MUNE ADH ERENCE AND INDIRECT HEM AGGLUTINATION Hans-Kristian Krogh and Olav Tender TABLE OF CONTENTS I.

Introduction........................................................................................................40

II.

Stratum Corneum Antigens.................................................................................40 A. Antigens Extractable by Aqueous Media................................................ 40 B. Antigens Requiring Chemical Extraction.............................................. 40

III.

Stratum Corneum Antibodies.............................................................................41 A. Nature of Antibodies...............................................................................41

IV.

Pathogenic Significance.......................................................................................42

V.

An Experimental Model...................................................................................... 45

VI.

Conclusion..........................................................................................................45

Acknowledgment.......................................................................................................... 47 References......................................................................................................................50

40

Autoimmunity in Psoriasis

I. INTRODUCTION Immunologically, stratum corneum (SC) represents a unique structure. Because of its extracorporeal location it has little or no access to the immune apparatus. Accordingly, several structures in SC may well be recognized as “ not-self” in pathological conditions. Indeed, it has been known for some time that all normal human sera contain true complement fixing antibodies to SC.356 22 26 33 34 These antibodies have been demonstrated by the immune adherence, mixed agglutination and indirect hemagglutination tests22 28 34 and by immunofluorescence methods.356 11 15 Data indicating in vivo binding of these antibodies to SC in lesions from patients with some skin diseases, particularly psoriasis, have also been collected,4 6 11 16 17 24 29 30 31 although another explanation has recently been presented.19 In the following we will survey the data available concerning the serological characterization of the SC antigens and antibodies.

II. STRATUM CORNEUM ANTIGENS Although it was demonstrated quite some time ago that keratins were antigenetic in animals,43 Parish42 did not succeed in detecting autoantibodies in human serum to human keratin. Until the last decade, little attention has been focused on “ insoluble” antigenic materials of SC. Recently, however, several papers from various laboratories have dealt with antibodies in human sera to these particular SC antigens 3'5111517 26-27'33-35'36

A. Antigens Extractable by Aqueous Media Antigens other than serum proteins have been demonstrated in aqueous extracts of homogenated SC, callus and psoriatic scales.12 12 1438 39 Fisher,12 using indirect hemagglutination of tanned erythrocytes sensitized with aqueous extracts of callus, found serological activity in 9 out of 66 sera from patients with various dermatoses. Some of these antigens in callus were shown to be glucoproteins not present in normal SC.1339 In studies using antisera raised by immunization, other investigators have detected antigens in extracts from human whole skin, SC and callus11238 39 and from skin of guinea pig,2 mouse and rat.45 These skin antigens are probably not related to the SC antigens to be discussed below. This, however, remains to be clarified. A comparison of skin extracts prepared by the various methods available, is therefore highly desirable. This chapter is essentially concerned with the SC antigens which are so firmly bound in the tissue that more drastic chemical procedures are required for their release. B. Antigens Requiring Chemical Extraction SC seems to contain several different antigenic determinants, extractable most suitably by phenol water extraction.33 34 These antigens are reactive in vitro and in vivo with antibodies indigenous in human sera. They are associated with the cell membrane and/or intercellular substance of the cornified cells. Some of the antigens involved have been isolated and their chemical and serological properties characterized.25 32 36 Using indirect hemagglutination tests with sheep erythrocytes sensitized with SC preparations, at least three immunologically distinct antigens were recovered from callus by phenol water and trypsin phenol extraction.41 Although the chemical composition of normal SC may differ from that of callus (see Reference 18), it was shown that the antigenic determinants responsible for the particular serological activity in SC are similar to those in the sediment of homogenated callus.21 22 25 28 The specificity of the three antigens bave been studied with preparations from man, guinea pig, and rabbit.32 35 36 Species-specific as well as common antigenic determinants

41 were demonstrated. Serological comparison of SC, callus, and psoriatic scales has revealed that psoriatic scales contain only two of these antigens,32 which were present in the water phase after phenol water extraction. One of these was resistant to treatment by periodate while the other was sensitive. The third antigen, common to both SC and callus, was recovered from the phenol phase. Inhibition and absorption studies showed that callus and psoriatic scales lacked two other antigenic components present in SC, but determinants specific for callus or psoriatic scales were not detected by these methods. This is in contrast to the results obtained with aqueous extractable antigens,1214*39 which showed that psoriatic scales contain antigens that were not present in normal SC. Furthermore, it has been shown that SC, callus as well as psoriatic scales contain both the common and the species-specific determinants.32 The erythrocyte-sensitizing activity of the various antigens, their presence in the water and/or phenol phases together with their sensitivity to treatment with periodate may reflect some characteristics of the chemical nature of the antigens involved. In an earlier study,25 it was shown that at least one of the antigens is of carbohydrate nature with an a-linked glucose residue as determinal group, and is associated with the intercellular substance and/or the cell membrane. It could well be related to the polysaccharide-containing surface coat of horny cells defined by Mercer et al.40 who applied histochemical methods adapted to the electron microscope. It may be that the SC antigens involved normally are hidden and are exposed during in vitro procedures such as cutting and disintegration (Chapter 5). Similarly, a conversion from their nonreactive form to a reactive state may take place in certain dermatoses, particularly psoriasis, as postulated by Beutner et al.5 and JabTonska et al.17 If this assumption is to be explained, experiments on isolating and purifying the various antigens in normal SC, callus, and psoriatic scales are needed for further characterization and comparison of the antigens involved. III. STRATUM CORNEUM ANTIBODIES By means of the tests of immune adherence, indirect hemagglutination,20 21 2433 34 and immunofluorescence,3 56 15 17 antibodies with specificity to SC have been demonstrated in all normal human sera tested. Sera from patients with agammaglobulinemia lack such antibodies.22 The antibodies levels from one individual to another differ greatly.34 When a panel of 1150 normal human sera was tested using indirect hemagglutination test the titers ranged from 8 to 16,384 with mode titers of 32 and 64. In the individual, however, the SC antibody level is rather constant with time,24 (see Section IV). A. Nature of Antibodies The initial work on SC antibodies in man was performed using the immune adherence test and antibodies of the IgM and IgG classes were detected.22 So far no studies have been made concerning any subclass differences within the IgG antibodies. The highest activity has been found in the IgM antibodies. Since the immune adherence test can only reveal complement fixing antibodies, antibodies belonging to other classes would not be disclosed. However, using the immunofluorescent test, IgA antibodies have also been disclosed. Combined with elution studies using psoriatic scales, antibodies have recently been demonstrated in the IgE class.11 SC antibodies were demonstrated in fetal sera and in sera from normal infants of various ages (Figure 1). IgM antibodies to SC are lacking in stillborns and during the first 2 months of life.24 During this time the titer of IgG antibodies shows a rather steep fall; thereafter the infants develop SC antibodies of their own, consistent with normal chronology of synthesis of immunoglobulins.

42

Autoimmunity in Psoriasis

FIGURE 1. Effect o f treatment with mercaptoethanol o f serum on titers of adherence activity in sera of infants up to 2 years of age. ( ▲ ) Same titer before and after treatment, (O) titer before treatment, and ( • ) titer after treatment. (From Krogh, H. K., Int. Arch. A llergy A ppl. Immunol., 37, 649, 1970. With permission.)

SC antibodies can also be detected in sera from other species,28 including rabbit and guinea pigs, but usually at low levels.36 However, antibodies in high titers can be raised by immunization of these animals with extracts of SC.27 36 The antibodies cross-react with SC antigens from the various species and behave as true autoantibodies, since they react with the skin of the antibody originator, both in man34 28 and in animals.35 Considering the fact that the antigens involved normally have no access to the immune apparatus, it would be difficult to explain how the autoantigens in SC could stimulate antibody production. Evidence available suggests that the antigens are firmly bound in SC and drastic extraction procedure is needed for their release.25 2834 Presumably, the antibodies may reflect heteroantibodies rather than true autoantibodies similar to the heteroantibodies against rabbit erythrocytes, which occur in all human sera.50 The stimulus may be some exogenous cross-reacting antigens, e.g., normally occurring in microorganisms sharing common antigenic determinants with the antigens in SC. This overlap in antigenicity may then result in autosensitization, since the immune apparatus recognizes the determinants as foreign. This assumption, however, remains to be proved.* IV. PATHO G EN IC SIGNIFICANCE Even though normal sera contain SC antibodies and normal skin bears SC antigens, they coexist without interacting, presumably due to the dermalepidermal barriers, consistent with a “ normal autoimmune state” . Complement binding, low molecular weight (3 S) antibodies which may readily leave the vascular compartment and reach SC, may be involved in the process of normal exfoliation.23 26 Detailed investigations are needed to elucidate this assumption. Editor’s note: see also Chapter 12.

43

FIGURE 2. Cryostat section of a subcorneal blister from a patient with pustular psoriasis, incubated with human erythrocytes. Strong adherence of erythrocytes to stratum corneum composing the roof of the blister. (Reduced from Magnification x 160.) (From Krogh, H. K., Int. A rch. Allergy A ppl. Immunol., 37, 649, 1970. With permission.)

The passage of immunoglobulins, complement, and other serum proteins into the horny layer is still an enigma. However, in certain dermatoses, including psoriasis, the normal barriers may be broken resulting in transepidermal leakage of plasma including SC antibodies and complement. This in turn may induce the formation of immune complexes in SC, resulting in an autoaggressive state. Whether this sequence of events primarily requires exposure of normally hidden antigens or changes in antigenicity is still not fully understood. In any case, in vivo binding of antibodies and complement in pemphigus foliaceus, subcorneal pustular dermatosis, and psoriasis (Figure 2) have been demonstrated.24 29 31 This can account for the selective lack of antibodies in the blister fluid from these patients. Recently these views have been given support by the results of extended studies using immunofluorescence techniques.4' 615-17 Although not disease-specific, there seems to be a characteristic fluorescent “ psoriatic” pattern which may have diagnostic significance in differentiating between psoriasis and psoriasis-like dermatoses.51617 It was also shown that SC antigens are more or less saturated with SC antibodies and C3, dependent on the stage of development of the psoriatic lesion.17 Furthermore, the presence of in vivo bound C3 within SC in psoriatic lesions was demonstrated ultrastructurally using a peroxidase-antiperoxidase technique.9 Consumption of specific antibodies in vivo and the results of elution studies in vitro

44

A u toimm unity in Psoriasis

FIGURE 3. Titers of antibodies to stratum corneum in sera from patients with pustular psoriasis ( ▲ , A), and pemphigus foliaceus ( • , O) related to generalized skin eruptions and clearing. The unbroken line expresses the mode titer of each sampling (X) of normal sera. (From Krogh, H. K., Int. Arch. Allergy Appl. Im m unol.,37, 649, 1970. With permission.)

support an autoimmune hypothesis.11 22 24 31 In association with generalized eruptions in pustular psoriasis, the titers of SC antibodies drop.24 Conversely, an increase of antibody activity is observed corresponding to the time of clearing (Figure 3). Thus there is an inverse association between the severity of the disease process and the titer of SC antibodies. These result have been confirmed in later studies.29 31 Similarly, a drop of rheumatoid factor activity has been demonstrated during active stages of psoriasis (Figure 4). The Waaler test performed with sequential sera taken at weekly intervals show lower titers during exacerbation. The anti-IgG factors are apparently bound in vivo in epidermis, and lost with the parakeratotic scales. Eluates prepared from psoriatic scales contain SC antibodies, anti-IgG factors and C3.31 The amount of anti-IgG factors lost from serum in this manner will be dependent on the extent and activity of the psoriatic process. These circumstances have to be considered when discussing anti-IgG activity in sera from patients with both psoriasis as well as arthritis.* Since the in vivo binding of SC antibodies is accompanied by the fixation of complement and rheumatoid factor, this reaction may implicate autoimmunity in the pathogenesis of some dermatoses, particularly psoriasis. In view of the well established pathogenetic potential of the complement cascade, it seems probable that the antigen/ antibody/complement complexes formed in SC may provide the “ signal” for chemotaxis of polymorphonuclear leukocytes, and the lysosomal enzymes generated may well account for some of the tissue damage encountered. These immunologic events may explain the findings of Pinkus and Mehregan44 that the papillary capillaries appear to discharge polymorphonuclear leukocytes through breaks in the basement membrane. Editor’s note: see also Chapter 10.

45

FIGURE 4. Titers with Waaler test using strongly sensitized sheep erythrocytes and weekly serum samples from a patient with psoriatic erythroderma and arthritis. (B) Serum from an earlier, clinically quiescent phase. (From Krogh, H. K. and T0nder, O., Scand. J. Im m unol.,2 , 45, 1973. With permission.)

Leukotactic activity of psoriatic scales has indeed been demonstrated by Langhof and Miiller37 and recently verified by the findings of Tagami and Ofuji.46-48 The transepidermal passage of polymorphonuclear leukocytes into the parakeratotic SC with the formation of Munro microabscesses may therefore readily be explained. V. AN EX PERIM EN TA L MODEL The above lines of indirect evidence have recently received support from the results of preliminary studies in guinea pigs immunized with SC antigens.27 The dermal-epidermal barriers were broken artificially by freezing. In animals with high titers of SC antibodies, a scaly erythematous plaque developed at the site. Biopsies from the lesions were studied with the immune adherence technique and examined histologically. The immune adherence test was strongly positive, with SC covering the lesions (Figures 5A and 5B). The inhibition by conglutinin favored an immunological adherence of erythrocytes (Figure 6). Evidently antibodies and complement had been bound in vivo, forming antigen/antibody/complement complexes necessary for the immune adherence to occur. Furthermore, microabscesses were found in SC, closely resembling the Munro abscesses of psoriasis (Figures 7A and 7B). VI. CONCLUSION In vivo bound autoantibodies and complement to SC in psoriasis and certain other dermatoses indicate that humoral autoimmune mechanisms are implicated in the pathogenesis of these diseases and may explain some of the histopathological and clinical features registered. In psoriasis, the primary causal defect resulting in the breakdown of the dermal-epidermal barriers and ensuing transepidermal leakage of plasma proteins is still unknown. Immunological mechanisms implicating humoral, Chapters 5 and 7, and cellular immunity (Chapters 8, 10, 11, 18, and 19) have been advocated.

46

Autoimmunity in Psoriasis

A

B FIGURE 5. Cryostat section of skin lesion specimen (immunized animal) incubated with human erythrocytes, 96 hr after local application of dry ice. Strong adherence of erythrocytes to stratum corneum covering the lesion. [(A) Reduced from Magnification x 50.] [(B) Reduced from Magnification x 160.]

Interestingly, T cells bave recently been demonstrated in situ as the predominating cells in the mononuclear cell infiltrate in fully developed psoriatic lesions.749 Apparently, however, they are preceded by polymorphonuclear leukocytes in the prelesional changes (see Chapter 7).

47

FIGURE 6. Cryostat serial section from same specimen as in Figure 5, treated with conglutinin prior to incubation with human erythrocytes. Adherence of erythrocytes to stratum corneum is inhibited by conglutinin. (Reduced from Magnification x 50). (From Krogh, H. K., Psoriasis: Proc. 2nd Int. Sym p., Yorke Medical Books, New York, 1977. With permission.)

However, the relevance of the various results reported and the concepts derived from them point to the need of further studies. The autoantigens and their corresponding antibodies should be better characterized and their involvement in various dermatoses investigated. More detailed studies using animal models and passive transfer experiments should also be conducted together with further experiments on cellular immunity to provide new insight into the cause of this puzzling disease. ACKNOW LEDGMENT These studies have been supported in part by grants from the Norwegian Council for Science and the Humanities and the Norwegian Psoriasis Association. The authors wish to thank Mrs. Inger Grimelund for skilled technical assistance.

FIGURE 7. Histology of skin lesion specimen (immunized animal) 96 hr after freezing. (Hematoxylin-eosin). (A) Microabscesses in hyperkeratotic stratum corneum. Foci of parakeratosis and patchy absence of the granular layer. Slight hydropic swelling of the epidermal cells and signs of degeneration of the collagen fibers. (Reduced from Magnification x 80). (B) (Part of A) Microabscess with numerous neutrophilic leukocytes in hyperkeratotic and parakeratotic horny layer. (Reduced from Magnification x 160.)

A

48 A u toimm unity in Psoriasis

FIGURE 7B

49

50

Autoimmunity in Psoriasis REFERENCES 1. Aoki, T. and Fujinami, T., Demonstration of tissue-specific soluble antigens in human skin by im-

munodiffusion, J. Im m un ol.,98,40, 1967. 2. Aoki, T., Parker, D., Turk, J. L., Analysis of soluble antigens in guinea pig epidermis. III. The localization of the different tissue-specific antigens in the epidermis, Immunology, 18, 213, 1970. 3. Beutner, E. H., Jabjbnska, S., Shu, S., and Chorzelski, T. P., Immunofluorescent appearance of stratum corneum antibodies as compared to pemphigus antibodies, Fed. Proc., 34, 1008,1975. 4. Beutner, E. H., Jablonska, S., Jarzabek-Chorzelska, M., Maciejowska, E., Rzesa, G ., and Chorzelski, T. P., Studies in immunodermatology. VI. IF studies of autoantibodies to the stratum corneum and o f in vivo fixed IgG in stratum corneum of psoriatic lesions, Int. Arch. Allergy Appl. Immunol.,

48,301, 1975.

5. Beutner, E. H., Jarzabek-Chorzelska, M., Jablonska, S., Chorzelski, T. P., and Rzesa, G., Autoimmunity in psoriasis. A complement immunofluorescence study, Arch. Dermatol. Res., 261, 123, 1978. 6. Binder, W ., Beutner, E. H., and Jablonska, S., Immunofluorescence studies on stratum corneum antibodies, in A utoim m unity in Psoriasis, Beutner, E. H ., Ed., CRC Press, Boca Raton, Fla., in press. 7. Bjerke, J. R., Krogh, H. K., and Matre, R., Characterization of mononuclear cell infiltrates in psoriatic lesions, J. Invest. D erm atol.,11, 340, 1978. 8. Braun-Falco, O. and Schmoeckel, C., The dermal inflammatory reaction in initial psoriatic lesions, Arch. Dermatol. Res., 258, 9, 1977. 9. Braun-Falco, O ., Maciejowski, W ., Schmoeckel, C., and Scherer, R., Immunoelectronmicroscopical demonstration of in vivo bound complement C3 in psoriatic lesions, Arch. Dermatol. Res., 260, 57, 1977. 10. Cormane, R. H., Hamerlinck, F., and Siddiqui, A. H., Immunologic implications of PU VA therapy in psoriasis vulgaris, Arch. Dermatol. Res.,265, 245, 1979. 11. Cormane, R. H., Hunyadi, J., and Hamerlinck, F., The role of lymphoid cells and polymorphonuclear leucocytes in the pathogenesis of psoriasis, J. Derm atol., 3, 247, 1976. 12. Fisher, P ., Soluble substances of human stratum corneum. I. Immunochemical and immunological study, J. Invest. D erm atol., 44, 43, 1965. 13. Fisher, J. P ., Soluble substances and antigen of human epidermis (analyses by electrophoresis and immunoelectrophoresis), J. Invest. D erm atol.,41, 336, 1966. 14. Forsey, R. R., Haberman, H. F., and Langman, J., Water soluble antigens of psoriatic scale, Arch. D erm atol., 91,512, 1965. 15. Jablonska, S., Chorzelski, T. P., Jarzabek-Chorzelska, M., and Beutner, E. H., Studies in immunodermatology. VII. Four compartment system studies of IgG in stratum corneum and of stratum corneum antigen in biopsies of psoriasis and control dermatoses, Int. A rch. Allergy A ppl. Immunol., 48, 324, 1975. 16. Jablonska, S., Chorzelski, T. P., Jarzabek-Chorzelska, M., and Beutner, E. H., Immunofluorescent findings in psoriasis o f the scalp, in Biology and Disease o f the Hair, Toda, K., Ishibashi, Y., Hori, Y., and Morikawa, F., Eds., University of Tokyo Press, 1976, 309.

17. Jablonska, S., Chorzelski, T. P., Beutner, E. H., Maciejowska, E., Jarzabek-Chorzelska, M., and Rzesa, G ., Autoimmunity in psoriasis. Relation of disease activity and forms of psoriasis to immunofluorescence findings, Arch. Dermatol. Res., 261, 135, 1978.

18. Jacobi, O ., Die Inhaltsstoffe des normalen Stratum Corneum und Callus menschlicher Haut. III. Milchsäure, Kreatin, Kreatinin, Harnstoff und Cholin, Arch. Derm. Forsch.,240, 107, 1971. 19. Kimura, S. and Nishikawa, J., An immunohistochemical analysis of the deposited immunoglobulins or fibrinogen in parakeratotic horny psoriatic horny layer and pemphigus skin lesions, Arch. Derm atol. Res., 261, 55, 1978. 20. Kristoffersen, T. and Krogh, H. K., Immune adherence with keratinized human oral mucosa and human serum, Scand. J. Dent. Res., 79, 31, 1971. 21. Krogh, H. K., Role o f complement in the adherence of erythrocytes to stratum corneum, Int. Arch. A llergy A ppl. Immunol., 34, 397, 1968. 22. Krogh, H. K., Antibodies in human sera to stratum corneum, Int. Arch. Allergy A ppl. Immunol., 36,415, 1969. 23. Krogh, H. K., Low molecular weight antibodies in human sera to stratum corneum, Int. Arch. A llergy A ppl. Im m unol.,31, 104, 1970. 24. Krogh, H. K., The occurrence of antibodies to stratum corneum in man, Int. Arch. Allergy Appl. Im m unol., 37, 649, 1970. 25. Krogh, H. K., The antigen involved in immune adherence with stratum corneum and human serum, Int. Arch. A llergy A ppl. Immunol., 38, 78, 1970.

51 26. Krogh, H . K., Antibodies to stratum corneum in man, in Im m unopathology o f the Skin. Labeled A n tibody Studies, Beutner, E. H ., Chorzelski, T. P., Bean, S. F., and Jordon, R. E., Eds., Dowden, Hutchinson & Ross, Stroudsburg, Pa., 1973, 402. 27. Krogh, H. K., The significance of stratum corneum antibodies: an experimental model in guinea pigs, in Psoriasis: Proc. 2nd Int. Sym p., Färber, E. M. and Cox, A. J., Eds., Yorke Medical Books, New York, 1977,55. 28. Krogh, H. K. and Tender, O ., Adherence of erythrocytes to stratum corneum of skin tissue sections, Int. Arch. A llergy A ppl. Im m unol.,34, 170, 1968. 29. Krogh, H . K. and T0nder, O ., Subcorneal pustular dermatosis. Pathogenetic aspects, Br. J. Dermatol., 83, 429, 1970. 30. Krogh, H . K. and Tender, O ., Immunoglobulins and antiimmunoglobulin factors in psoriatic lesions, Clin. Exp. Immunol., 10, 623, 1972. 31. Krogh, H. K. and T0nder, O ., Antibodies in psoriatic scales, Scand. J. Im m unol.,2 , 45, 1973. 32. Krogh, H. K. and T0nder, O ., Comparison of human stratum corneum, callus and psoriatic scales by means of serological methods, Int. Arch. Allergy Appl. Immunol. ,53, 434, 1977. 33. Krogh, H . K. and T0nder, O ., Immune adherence and indirect hemagglutination tests for the detection of stratum corneum antibodies, in Autoim m unity in Psoriasis, Beutner, E. H., Ed., CRC Press, Boca Raton, Fla., 1981, chap. 20. 34. Krogh, H . K., Maeland, J. A ., and T0nder, O ., Indirect haemagglutination for demonstration of antibodies to stratum corneum of skin, Int. Arch. Allergy A ppl. Immunol., 42, 493, 1972. 35. Krogh, H . K., Maeland, J. A ., and Tender, O ., Species specificity of skin antigens prepared by phenol water extraction, Int. Arch. Allergy A ppl. Immunol., 47, 839, 1974. 36. Krogh, H. K., Maeland, J. A ., and Tender, O ., Specificity of antigens in aqueous phenol extracts of skin examined by means of guinea pig and rabbit immune sera, Int. Arch. Allergy Appl. Immunol., 49, 519, 1975. 37. Langhof, H . and Müller, H ., Leukotaktische Eigenschaften von Prosiasisschuppen, Hautarzt, 17, 101, 1966. 38. Leonhardi, G ., Ldhner, L., Gürenci, J., and Schmidt, J., Auftrennung wasserlpslicher, epidermaler Proteine mittels Disc-Elektrophorese, Arch. Klin. Exp. D erm .,234, 61, 1969. 39. Matoltsy, A . G. and Matoltsy, M. N ., A study of the soluble proteins of normal and pathologic horny tissues by a modified disc electrophoresis technic, J. Invest. D erm atol., 41,255, 1963. 40. Mercer, E. H ., Jahn, R. A ., and Maibach, H. I., Surface coats containing polysaccharides on human epidermal cells, J. Invest. Derm atol., 51, 204, 1968. 41. Maeland, J. A ., Krogh, H. K., and Tender, O ., Heterogeneity of antigen from callus of man, Int. Arch. A llergy A ppl. Immunol., 46, 619, 1974. 42. Parish, W. E ., General concepts of autosensitivity in disease, in Advances in Biology o f Skin, Vol. 11, Montagna, W. and Billingham, R. E., Eds., Meredith Co., Oxford, 1971, 233. 43. Pillemer, L ., Ecker, E. E., and Wells, J. R., The specificity of keratins, J. Exp. M ed., 69, 191, 1939. 44. Pinkus, H. and Mehregan, A. H ., The primary histologic lesion of seborrhoic dermatitis and psoriasis, J. Invest. D erm atol.,46, 109, 1966. 45. Räsänen, O ., Antigens of rat and mouse epidermis. Immunoelectrophoretic, double gel diffusion and immunofluorescence studies, Acta Pathol. Microbiol. Scand., Suppl. 198, 1968. 46. Tagami, H . and Ofuji, S., Leukotactic properties of soluble substances in psoriasis scale, Br. J. Derm atol., 95, 1, 1976. 47. Tagami, H. and Ofuji, S., Characterization of a leukotactic factor derived from psoriatic scale, Br. J. Derm atol., 91, 509, 1977. 48. Tagami, H. and Ofuji, S., Chemotactic factors in psoriatic scales, in A utoim m unity in Psoriasis, Beutner, E. H ., Ed., CRC Press, Boca Raton, Fla., 1981, chap. 8. 49. Tender, O. and Krogh, H. K., Hemadsorption techniques for the in situ characterization of mononuclear cells in tissue, in Autoim m unity in Psoriasis, Beutner, E. H ., Ed., CRC Press, Boca Raton, Fla., 1981, chap. 23. 50. Tender, O ., Natvig, J. B., and Matre, R., Antibodies in human sera to rabbit erythrocytes, Immunology, 12, 629, 1967.

53 Chapter 5 IM M UNOFLUORESCENCE FINDINGS ON STRATUM CORNEUM ANTIBODIES, ANTIGENS, AND TH EIR REACTIONS IN VITRO AND IN VIVO AS RELATED TO REPAIR AND PSORIASIS* Ernst H. Beutner, Walter L. Binder, Stefania Jabionska, and Vijay Kumar TABLE OF CONTENTS I.

Introduction....................................................................................................... 54

II.

Nature of SCAb to Insoluble SC Antigens Detected by Indirect IF Staining.. .55 A. Autoreactivity of SCAb...........................................................................56 B. Allo-Specificity and Species Specificity of SCAb...................................56 C. Universal Nature of SCAb....................................................................... 57 D. IgG and IgM Class, Complement Fixing S C A b.....................................57 E. SC Antigens Detected by Indirect IF Staining........................................ 57 F. Tissue Distribution of SC Antigens Detected byIF Staining...................58 G. In Vivo Reactions of SCAb with Normal S k in .......................................58

III.

Sequestration, Conversion, and Reactions of SC Antigens in Tissue Culture and In V ivo........................................................................................................58 A. Nonreactivity of Horny Layer in Normal Skin Explants in Culture....................................................................................................59 B. Conversion of SC Antigens to Reactive Forms by Trauma and in Psoriasis..................................................................................................60 1. SCAg Conversion Reactions at the Cut Edge of Callus............... 60 2. SCAg Conversion by Scratching Skin Explants......................... 60 3. SCAg Conversion by Stripping of Skin Explants....................... 62 4. Interpretation of SCAg Conversion Findings............................. 63 C. Relation of SCAg Conversion in Tissue Culture to the Apparent In Vivo Binding of SCAb...........................................................................64 1. Comparisons of SCAg Conversion Reactions in Tissue Culture and In V ivo.................................................................................64 2. Direct vs. Indirect IF Studies of SCAg Sites in Psoriatic Scales.......................................................................................... 64

IV.

Biochemical Basis of SCAg Conversion Reactions............................................ 67 A. Extraction Studies on SC Components which Sequester Insoluble SCAg......................................................................................................67 B. Enzyme Degradation Studies on SCAg and on Macromolecule which Sequesters SCAg.................................................................................... 67 C. Synthesis of Findings on Nature and Structure of SCAg System..........6 8 1. Evaluation of Data on the Biochemical Nature of Macromolecules which Sequester SC A g................................... 6 8 2. Evaluation of Data on Biochemical Nature of Insoluble and Soluble SC A g.............................................................................70 3. Structural Relationships of the SCAg System to the Cell Membranes of Corneocytes........................................................71

*

This research was supported in part by grants from Owen Laboratories, Division of Alcon Laboratories, the Polish Academy of Science, and the IF Testing Service.

54

A u to im m u n ity in P soriasis

V.

Relation of SCAg-SCAb-C Complexes to the Pathogenesis of Fully Developed Psoriatic Lesions................................................................................................ 71

VI.

Relation of SCAg Conversion and SCAg-SCAb-C Complexes to Normal Repair and Responses Leading to Psoriasis......................................................73 A. Relation of SCAg-SCAb to Repair Mechanisms.....................................74 B. Relation to Horny Layer to Predisposition to Psoriasis......................... 74 C. Relation of the Horny Layer and SCAg-SCAb-C Complexes to the Induction of Psoriasis.............................................................................74 D. Relation of PMN to the Induction of Psoriasis.......................................75

VII.

Implicated Sequence of Immunologic Reactions in Skin Repair and Development of Psoriasis.................................................................................76

VIII. Genetic Implications of the Suggested Role of the Horny Layer in the Predisposition to Psoriasis...............................................................................76 References....................................................................................................................... 7 7

I. INTRODUCTION Autoimmunity, i.e., specific immune responses to identifiable solid or fluid components of the tissue of their producer, may be cellular or humoral. The cellular responses associated with psoriasis to date have not been of an autoimmune nature (Chapters 15 and 18) but appear to be secondary events mediated by humoral factors (Chapter 15). Thus far only autoantibodies, most notably the stratum corneum (SC) antibodies or SCAb, are implicated in the pathogenesis of psoriasis1 14 28-34 36' 41 (Chapters 1, 4 , 6 , and 7). On the one hand, SCAb do not appear to be the only autoimmune responses which come into play in the pathogenesis of psoriasis; certain antinuclear antibodies, 20 rheumatoid factor40 44 (Chapters 4 and 10 ), and possibly other types of autoantibodies, notably the widely studied but poorly understood universal autoantibodies directed to the cytoplasm (Cyto Ab) of keratinocytes1 2 18 19 54 58 59 may possibly also be involved. On the other hand, a number of independent lines of evidence implicate the horny layer as a primary factor in the predisposition to , 22 53 induction Qf , 3 14-16 21 29 53 and perpetuation op. 14.29.37.41.56.57 pSoriatic lesions as indicated in Sections V and VI of this chapter. Reactions of SC antigens with SCAb appear to be responsible for the role of the horny layer in psoriasis. Thus, SCAb and their in vivo reactions in the skin (and possibly also in the bloodstream) of their producer clearly merits further study. If we consider the fact that not only SCAb but also Cyto Ab and many other autoantibodies occur in all normal sera it is evident that these are not products of “ forbidden clones” 17 but can be thought of as products of “ nonforbidden clones” 2 4 7 24 (Chapter 1). The most important difference between the autoimmune responses of such nonforbidden clones and autoantibodies of the type that cause pemphigus6 47 is that the latter react in vivo with self antigens in the normal skin while SCAb and Cyto Ab and other autoantibodies of this type do not. In vivo reactions of nonforbidden clone types of autoantibodies occur only with hidden or altered or novel or abnormal self antigens. 2 4 7

55 In the context of this book we focus our attention on one abnormal condition, psoriasis. But this is by no means the only one in which in vivo reactions of SCAb appear to play a role. Most commonly their in vivo reactions appear to be secondary, e.g., Jabionska et al.32 report the finding of SC deposits of IgG and/or complement in about 5% of diverse dermatoses with patterns of the type associated with SCAb reactions (see Figures). As indicated below the binding of SCAb at sites of trauma implicates them as factors in tissue repair. From the viewpoint of the individual who produces an autoantibody the most important questions are first whether it reacts in vivo, and second if it does so whether it has a beneficial or damaging effect. From this viewpoint the SC antigen conversion reaction which renders SC antigen reactive is of critical importance. Such conversion reactions are by no means unique to SC antigens. They have also been demonstrated unequivocally for Cyto Ab,1 RF,48 and other “ physiologic” autoantibodies which are either universal or are readily elicited by immunization (see Chapter 1). SCAb fall into two groups, those directed to soluble SC antigens as revealed by immune adherence and indirect hemagglutination38 39 (Chapter 4) and those which react with insoluble SC antigens as demonstrated by immunofluorescence (IF) test, notably, indirect IF8 and complement (indirect) IF on normal skin.9 The first clear-cut demonstration of a difference between the specificity of SCAb directed to soluble and insoluble SC antigens was reported by Binder and associates1214 (Chapter 6). Whether tests of psoriatic lesions by direct IF8,31,33 (Chapter 21) and mixed agglutination on tissue sections40 (Chapter 20) reveal in vivo reactions of SCAb with soluble or insoluble SC antigens or both is not clear as yet. Elution studies2837 indicate that at least some of the binding is to soluble antigens while studies on the SC antigen conversion reaction point to probable reactions with insoluble SC antigens. This chapter deals primarily with the relation between reactions of SCAb to insoluble SC antigens as seen by indirect IF tests on frozen sections and those which occur as a result of SC antigen conversion both in tissue culture and in vivo. We focus our attention on the role of the SC conversion reaction in normal repair mechanisms and in psoriasis. II. NATURE OF SCAb TO INSOLUBLE SC ANTIGENS DETECTED BY INDIRECT IF STAINING Figures 1A to 1C depict indirect IF staining reactions of SCAb on normal human glabrous skin, together with a control. The stratum granulosum reacts more strongly than the SC particularly at higher serum dilutions (Figure 1C) but the stratum spinosum fails to react, thus indicating that the SC antigens form in the stratum granulosum. Normal human skin specimens vary considerably in their reactivity with SCAb while normal glabrous skin of monkeys gives more constant SCAb titers with a given serum (Chapter 21). Thus either strongly reactive human or any normal monkey glabrous skin is used to obtain reproducible SCAb titers. Failures to demonstrate SCAb by indirect IF staining in earlier studies50 appears to have been due to technical problems. Volar skin and callus of the mechanical hyperkeratosis type reacts with SCAb at cut edges (Figures ID and IE).35 Absorption studies serve to document the immunologic specificity of this reaction and the identity of the antibodies detected with the SCAb demonstrable on sections of glabrous skin.1214 Titers of SCAb on the cut edge of callus or volar skin are frequently one or more doubling dilutions lower than on glabrous skin. Sera with low titers of SCAb on glabrous skin usually give negative reactions on the cut edge of callus in indirect IF tests.

56

A u toimm unity in Psoriasis

A

B

c

FIGURE I . Indirect IF tests for SCAb on frozen 4 nm sections of normal human skin (left side) and cut edge of normal human callus (right side) using an anti-IgG conjugate with a molar F/P ratio of 1.2 diluted to contain !4 unit/ml in a test system as described in Chapter 21 under the following conditions: (A) (Top) — Normal skin section treated as conjugate control (conjugate alone). The horny layer is almost invisible. This is a negative IF reaction. (Magnification x 400.) (B) (Middle) — Section of same normal skin treated with normal serum (with a titer of SCAb of 80) diluted 1:10, washed and treated with conjugate. Note +3 reaction of SCAb both in the stratum granulosum and the SC. (Magnification x 400.) (C) (Bottom) — Section of same normal skin as for Figures 1A and IB treated with same normal serum as Figure IB, diluted 1:20 and same conjugate. Note 3 + reaction of SCAb in the stratum granulosum and weak positive reaction in the SC. (Magnification x 400.) (D) (Left) — Normal callus section treated as conjugate control (as for Figure 1A). Note negative reaction at cut edge of callus. (Magnification x 400.) (E) (Right) — Section of same normal callus as for Figure ID treated with normal serum diluted 1:10 (as for Figure IB). Note 3 + reaction at cut edge of callus. The central portion of the callus remains unreactive under these conditions. (Magnification x 400.) (Figures ID and IE are reprinted from Beutner, E. H., Binder, W. L., Jabjonska, S., and Kumar, V., in The Epidermis in Disease, Marks, R., and Christophers, E., Eds., MTP Press, Lancaster, England, 1981,333. With permission.)

The basic properties of the SCAb detected by IF staining methods (Chapter 21) and the insoluble SC antigens with which they react can be summarized as follows. A. Autoreactivity of SCAb Indirect IF staining titers of SCAb on sections of normal glabrous skin of their producers do not differ significantly from their titers on other normal skin sections of some other individuals.8 B. Allo-Specificity and Species Specificity of SCAb Recent unpublished absorption studies of Dabski and Beutner reveal that individual

57

FIGURES ID and IE.

differences exist in the SCAb and the SCAg with which they react. That is, SCAb are not only autoantibodies but also, under appropriate test conditions, alio- or iso-antibodies. Human SCAb give some cross reactions with the SC antigens of monkey, pig, rat, guinea pig, rabbit, and probably also other species. Conversely, SCAb of monkey, rabbit, and pig (and probably also other species) give some cross reactions with human SC antigens in IF tests.8,14,226 C. Universal Nature of SCAb The SCAb detected by IF staining occur in all human sera tested to date.5814 The range of titers of SCAb found in normal human sera do not differ significantly from those found in psoriatic sera.8 Titers of SCAb detected by indirect IF staining do not drop during outbursts of psoriasis as do those detected by indirect hemagglutination41 (Chapter 4). D. IgG and IgM Class, Complement Fixing SCAb While both IgG and IgM class SCAb occur in human sera the titers of the IgG class autoantibodies tend to be higher in adult sera14 (Chapter 6). They fix complement as revealed by complement IF staining5 (Chapter 21) as shown in Table 1. E. SC Antigens Detected by Indirect IF Staining The insoluble SC antigens detected by indirect IF tests of normal skin appear to be proteins as revealed by enzymatic studies. That is, they are degraded by each of three serine proteases.42 However, IF tests of trypsin treated callus give reactions with SCAb that can be removed by absorption with the soluble SC antigens46 in the water phases of phenol-water extracts of trypsin digested callus.226 The latter SC antigens do not remove the SCAb to the insoluble SC antigens demonstrable by IF staining of normal skin or callus. Whether the SC antigens detected by mixed agglutination on normal tissue sections40 (Chapter 4) are the same as those demonstrable by indirect IF staining remains to be determined.

58

A u to im m u n ity in P soriasis

Table 1 CROSS REACTIVITY OF SCAb WITH CUT EDGE OF CALLUS AND VOLAR SKIN AS DEMONSTRATED BY INDIRECT IF STAINING AND COMPLEMENT IF STAINING FOR SCAb Intensity of indirect IF staining of SCAb with 1:10 dilution o f sera (and SCAb titers o f sera)

1. Normal human serum with SCAb 2. Normal human serum Abs with callus6 3. Fresh normal human serum 4. Heated normal serum + EDTAC a

*

c

Method testing

Skin SC (glabrous)

Volar SC cut edge

Callus cut edge

Indirect IF“

+ +(20)

+ (10—20)

+ (10)

(Same as 1) Comp. IF6 (Same as 3)

—

+ + —

—

—

No test

+ +

No test

—

Characteristics of conjugates were as follows: (1) anti-IgG goat antibodies with H and L chain antibodies, molar F /P 1.2 anti-IgG content 8 units/m f, diluted to 1/8 un it/m l (see Chapter 21); (2) anti-C3 (goat anti f32A), molar F /P 2.4 anti-C3 content 16 u n its/m l, diluted to Vi u n it/m f; and (3) anti-C4 goat antiserum, molar F /P ratio 2.5, anti-C4 content 48 un its/m l, diluted to contain !4 un it/m l. Abs = absorption with powdered normal human callus; three successive absorptions with 2 to 3 mg ground callus per milliliter of serum (see Reference 11 for details). Heat inactivation at 56°C for 30 min; diluent with ethylene diamine tetra-acetic acid (EDTA).

F. Tissue Distribution of SC Antigens Detected by IF Staining The SC antigens under consideration in this chapter occur only in glabrous and volar skin (Figure 1). The identity of the two is evident from the results of absorption studies summarized in Table 1. As indicated by the data summarized in the following Chapter 6, the insoluble SC antigens of mucous membranes demonstrable by indirect IF staining differ from those of volar and glabrous skin. G. In Vivo Reactions of SCAb with Normal Skin Though SCAb are autoantibodies (see Section II.A.) they fail to react in vivo with their homologous antigens in normal glabrous or volar skin as demonstrated by direct IF tests.58 That is, even when the normal intact stratum corneum is exposed to SCAb no reaction occurs. SCAb only react at sites of trauma (see next section). III. SEQUESTRATION, CONVERSION, AND REACTIONS OF SC ANTIGENS IN TISSUE CULTURE AND IN VIVO Three possible reasons can be advanced for the failure of SCAb to react in vivo with the horny layer. One is that SC antigens (SCAg) on the surface of the skin lie in an anatomically sequestered position, i.e., a position which is normally inaccessible to SCAb because of its location on the surface of the skin. Krogh advances this thesis and expresses the view that SCAb are unique in this respect41 (Chapter 4). Alternatively, the SCAg may exist in a nonreactive form in the normal state because they lie in a biochemically sequestered position within macromolecules on the surface of cor-

59

A

B

FIGURE 2. Explants of normal monkey skin cultured for 48 hr in a normal human serum with SCAb titer of 20. Explants of monkey skin about 2 x 2 mm2 cut from Vi mm thick strip of monkey skin (prepared with keratome), placed on filter paper rafts and cultured on normal human serum with SCAb using a stainless steel screen to support the explant bearing rafts. Frozen section cut at 4 nm and stained by IF as follows: (A) (Top) — Direct IF stain with anti-IgG conjugate as specified for Figure 1. The SC is negative. Only the top edge of SC is visible (because of some adherent debris). (Magnification x 400.) (B) (Bottom) — Indirect IF stain for SCAb with a 1:10 dilution of the same serum in which explant was cultured. Note the + to 2 + reaction in SC. (Magnification x 400.)

neocytes. A third possibility is that both mechanisms play a role. To gain an understanding of why SCAb normally fail to bind to the horny layer in vivo, tissue culture studies were undertaken using methods comparable to those which yield binding of pemphigus antibodies to skin explants as well as the development of acantholytic “ lesions” in them.1347 That is, explants of normal monkey skin supported on filter paper rafts are cultured on normal sera with elevated SCAb titers (comparable to the titers of pemphigus antibodies which elicit the above mentioned effects). The cultured explants can be examined both by direct and indirect IF tests for the binding of SCAb in culture and in frozen sections. Tissue culture studies together with direct and indirect IF tests of human skin lesions lead us to the conclusion that both anatomic and biochemical barriers prevent SCAb from reacting with SCAg of normal skin in vivo but that the biochemical barriers to permeability play a more important role. The experimental findings are as follows. A. Nonreactivity of Horny Layer in Normal Skin Explants in Culture Normal skin explants grown on sera with titers of 40 or more fail to bind the antibodies in culture as seen by direct IF tests (Figure 2A); but pemphigus antibodies do react under these conditions.24 7 Yet indirect IF tests with the same sera on frozen sections of the explants with the same sera in which they are cultured give strongly positive SCAb reactions (see Figure 2B). This difference is comparable to the failure of SCAb to react in vivo with the SCAg in the horny layer as seen by direct IF and the autoreactivity of SCAb with their producers’ skin, (see Section II.G.) To determine whether this failure of SCAb to react is due to anatomical or biochemical barriers, explants cultured with their epidermal side down (i.e., bathed in sera with SCAb) were

60

A u to im m u n ity in P soriasis

examined by IF tests.42 These explants also failed to bind SCAb in culture. Explants cultured with the dermal side down and with repeated flooding of the skin surface with SCAb containing serum (that also saved as culture medium) gave comparable negative reactions. These findings indicate that the anatomical location of the SCAg on the surface of the normal avascular epidermis cannot, of itself, account for their failure to react with SCAb. This conclusion is borne out by the failure to find signs of SCAb reactions in areas of skin on which blood clots have formed in vivo. The tissue culture findings further suggest, but of themselves do not prove, that the SCAg are probably biochemically sequestered. However, this does not preclude the possibility that anatomic sequestration may also play a role. Subsequent direct IF studies of psoriatic scales suggest that the latter may be true (see Section III.C.2.). B. Conversion of SC Antigens to Reactive Forms by Trauma and in Psoriasis Observations on skin biopsy specimens suggest that trauma such as cuts, scratches, and stripping with adhesives may convert SCAg from their normal, nonreactive form which can bind SCAb and fix complement (C) to yield immune complexes (SCAgSCAb-C) in vivo. For example, at the sites of scratches in biopsy specimens of pruritic skin lesions, IgG, other Ig and sometimes also C3 deposits are bound to SCAg sites, thus suggesting the possibility that SCAb binding occurs in vivo at these sites. To analyze this question the same tissue culture technique can be used as for the studies described in the preceding Section III.A. These studies reveal the following reactions. 1 . S C A g C o n versio n R ea ctio n s a t th e C u t E d g e o f C allus

Human callus taken from areas of mechanical hyperkeratosis when cut, soaked overnight in human sera with SCAb, washed in PBS, frozen, sectioned, and stained for IgG deposits by direct IF (with a conjugate with a molar F/P of two or less, diluted to Va unit/m i) reveal binding of SCAb at the cut edge under some but not all conditions.51214 If the SCAb titers of the normal serum is five, little or no binding occurs in 24 hr. Also sera with titers of 40 or more give negative reactions if incubated for only 1 hr. If, however, such sera with elevated SCAb titers are incubated with pieces of callus for 24 hr, positive reactions occur at the cut edge as shown in Figure 3B. They do not appear at the desquamating surface of the callus, however. The reaction of SCAb at cut edges can be titrated. Sera with elevated SCAb titers, if first absorbed with callus homogenate give lower titers of SC staining at the cut edge (compare Figures 3A and 3B). These findings point to the immunologic specificity of the reaction of SCAb at the cut edge of callus. Explants of volar skin give comparable reaction patterns at cut edges under these experimental conditions. 2. S C A g C o n versio n b y S cratch in g Skin E xp la n ts

Quantitative studies of Binder12 and Binder et al.14 on the effects of scratching normal monkey skin explants shed light on the kinetics of the SCAb binding reactions. Both human and rabbit SCAb bind to the edges of the scratched SC under some but not all conditions as revealed by direct IF staining of frozen sections of the explants with anti-IgG conjugates (which have comparable properties to those described in Section III.B.l) (see Figure 3C). The SCAb binding in explants at sites of scratches depends on the titer of the SCAb and the time of incubation as indicated in Chapter 6.11 Trace to weak SCAb reactions occur as early as 4 to 8 hr using sera with moderate SCAb titers as culture media. Maximum reactivity requies 48 to 72 hr. Considering the fact that a maximum SCAb reaction requires only Vi hr in the direct or complement (indirect) IF test with the same

61

A

B

FIGURE 3. SCAg conversion reactions induced by cutting normal human callus, by scratching normal monkey skin and by stripping normal human skin and placing them in tissue culture with SCAb. The SCAg conversion reactions are demonstrated by maintaining the explants on rafts exposed to normal serum with SCAb and testing frozen 4p sections for binding of SCAb in culture by direct IF staining for SCAb binding (using the same conjugate as for Figure 1) or for complement fixation by the bound SCAb using an anti-C4 conjugate (molar F/P ratio of 2.5 diluted to !4 unit/ml). The test conditions are as follows: (A) (Top) — Normal human callus soaked for 24 hr at room temperature in a 1:16 dilution of normal human serum (SCAb titer of 40) that had been absorbed with a homogenate of normal callus. Note negative direct IF reactions for IgG. (Magnification x 400.) (B) (Bottom) — Same conditions as for Figure 3A with a 1:16 dilution of the unabsorbed form of the same normal human serum followed by treatment with the same conjugate. Note positive reaction of SCAb at cut edge of callus. (Magnification x 400.) (C) — Normal monkey skin explant scratched and cultured for 48 hr on a fresh normal human serum with a SCAb titer of 20. A frozen section stained for C4 by direct IF revealed complement fixation of SCAb bound to the edge of the cut into the horny layer. Some reaction also occurs in the stratum spinosum. Table 2 lists the effects of incubation time and SCAb titers on the rate of SCAb binding in this reaction. (Magnification x 400.) (D) — Normal human skin explant cultured for 4 hr in a normal human serum with a SCAb titer of 40 and stained by direct IF for IgG. Note negative reaction in the SC. (Magnification x 400.) (E) — Same conditions as for Figure 3D except that skin was stripped with scotch tape 20 times. Note binding of SCAb in culture. Complement can also fix to the SC under these conditions. (Magnification x 400.) (Figures 3A to 3E are reprinted from Beutner, E. H., Binder, W. L., Jabfonska, S., and Kumar, V., The Epidermis in Disease, Marks, R., and Christophers, E., Eds., MTP Press, Lancaster, England, 1981, 333. With permission.)

sera, it seems evident that SCAg conversion reaction in skin explants which follow scratching and prolonged incubation involves first a slow reaction, quite probably an autolytic degradation of the SC, and a second more rapid immunologic reaction of SCAb.

62

A utoimm unity in Psoriasis

FIGURE 3C

FIGURE 3D

3. SCAg Conversion by Stripping o f Skin Explants Kumar et al.42 demonstrated that stripping of normal human skin (obtained from radical mastectomies) followed by the preparation of explants and their cultivation in sera with high SCAb titers give rise to positive SCAb binding reactions at the stripped surface in 4 hr as seen by direct IF staining for IgG (using the same conditions de-

63

FIGURE 3E

scribed in Section III.B.l) while unstripped control explants fail to bind SCAb at their surface (see Figures 3D and 3E). Comparisons of SCAb binding to explants cultured dermal side down vs. epidermal side down revealed no detectable difference. These studies show that the reactions of the complement fixing SCAb with the stripped surfaces of skin explants are restricted by structural or biochemical components at the surface of the horny layer. 4. Interpretation o f SCAg Conversion Findings The presence of SCAb in all normal sera and the conversion of SCAg to a reactive form by trauma as well as the fixation of complement by the SCAg-SCAb complexes suggests that this reaction leads to release of the kinins and chemotaxins C3a, C5a, and C567 in vivo from the complement cascade. The polymorphonuclear neutrophils (PMN) attracted by the latter may in turn be expected to aid in the phagocytosis of the SCAg-SCAb-C complexes and in the normal repair of the injured skin. In effect, the observations on SCAb (Section II) and on SCAg conversion reactions (Sections II.B.l to 3) suggest that their normal function is to aid in repair of skin injury. Importantly, the tissue culture model used in the above studies on the SCAg conversion reactions differ from the in vivo situation in that the latter includes the interaction with inflammatory cells, most notably the PMN. As Jabfonska et al.28,29 (Chapters 3 and 7) and Glinski et al.23 (Chapter 16) have shown, PMN not only invade sites of trauma early in the repair process but also release hydrolytic enzymes which act specifically on the horny layer. The breakdown products are, for the most part, nonantigenic, though in the in vivo situation some of the products of the SC retain antigenicity (see Section III.C.). We may ask what evolutionary advantages are gained by mammals which fail to degrade damaged components of skin (or other tissues) to completely nonantigenic forms. It may well be that the failure to do so and the resultant recruitment of the immunologic apparatus together with the activation of the complement cascade contribute to the survival of the species by playing a key role in normal repair. Since the in vivo reactions of such physiologic autoantibodies as the SCAb appear to be wide-

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A u to im m u n ity in P soriasis

spread in the tissue of mammals (see Introduction and Chapter 1) and since these reactions may well play a role in homeostasis, they clearly merit further study, particularly since imbalances in this type of homeostatic mechanism are now implicated in the etiology and pathogenesis of psoriasis (see Sections V and VI).

C. Relation of SCAg Conversion in Tissue Culture to the Apparent In Vivo Binding of SCAb Direct IF studies of skin biopsy specimens of sites traumatized by physical injury or secondarily affected by other dermatoses frequently reveal IgG deposits in patterns quite comparable to those of SCAb binding induced in skin explants by trauma (Section III.B) and similar to, but less extensive than those produced by indirect IF staining with SCAb on adjacent frozen sections of the skin biopsy specimen. According to the studies of Jablonska et al.32 (Chapter 7) such reactions occur in about 5% of specimens from diverse dermatoses. In fully developed psoriatic lesions a somewhat different pattern of in vivo deposits of IgG, other Ig, C3, other C components, and fibrin occur in SCAg sites5831-34 (Section V, Chapter 7). Figure 4A to 4C depicts such reaction patterns in a fully developed psoriatic lesion. In this chapter, we address two questions regarding the observed direct IF staining reactions in psoriatic lesions. First, are these identical to the SCAb reactions induced in skin explants by trauma? They do not appear to be identical (Section II.C.l). Secondly, are they due to in vivo binding of SCAb? In part, yes (Section V). The observations relevant to the first question are as follows. 1. C o m p a riso n s o f S C A g C o n versio n R ea ctio n s in T issue C u ltu re an d In V ivo

Absorption of sera with ground callus removes the SCAb reactive with the insoluble SCAg detected by indirect IF staining of normal skin (if absorption is done with allogenecially matched callus) but not the SCAb reactive with trypsin digested soluble SCAg detected by indirect hemagglutination as demonstrated by Binder et al.14 (Chapter 6). This may be expected since ground callus is insoluble and contains a relatively large amount of “ cut surface” . However, elution studies of psoriatic scales which appear to contain in vivo bound SCAb833 40 (Chapters 4 and 7) with acid (pH 3 glycineHC1) buffers only yield SCAb to the soluble SCAg detected by indirect hemagglutination.1228 The SCAb to insoluble SCAg detected by indirect IF staining only appear in the primary washing with neutral (pH 7.2) phosphate buffered saline as indicated in Table 2. As indicated in Section III.B.4, another difference between the in vitro reactions of SCAb in traumatized skin explants and the in vivo responss to trauma becomes apparent from the detailed histologic studies of Jablonska et al.32 (Chapter 3). Within less than 1 hr of scratching or stripping PMN invade the site of trauma. These observations lead us to the tentative conclusion that SCAb to insoluble SCAg probably bind in vivo initially and/or transiently; secondary changes, most probably those mediated by hydrolytic enzymes of PMN, degrade the insoluble SCAg to nonreactive fragments and expose the soluble SCAg. Biochemical studies of the horny layer as they relate to SCAg sheds further light on this interpretation (see Section IV).

2. D ire c t vs. In d irect IF S tu d ies o f S C A g S ites in P so ria tic Scales If we accept the above-mentioned results of elution studies as well as the direct IF and mixed agglutination findings of Ig, C, and RF binding to SCAg sites on fully developed psoriasis lesions (Chapters 4 and 7) as evidence for the existence of reactive forms of SCAg in psoriatic scales we can then ask to what extent these are saturated in vivo. Comparative direct and indirect IF studies of the distribution of SCAb combining sites in psoriatic lesions (four compartment test, Chapter 21) reveal that while

65

A

B

FIGURE 4. Psoriatic lesion tested by direct and indirect IF staining. (A) Psoriatic lesion examined by direct IF staining with a conjugate (anti-C4) absorbed free of detectable antibodies by two successive absorptions with normal human serum (test for nonspecific staining). Note negative IF reaction. This serves as one of the negative controls in the four compartment test (see Chapter 21). (Magnification x 400.) (B) Same psoriatic lesion as for Figure 4A examined by direct IF staining for in vivo deposits of C4. Note strongly positive reaction particularly over the dermal papillae. Some, but not all of the IgG deposits have a linear pattern of the type associated with SCAb binding as demonstrated by the four compartment test. This is implicated as one of the primary events in the pathogenesis of psoriasis (Section VI of text). The more homogeneous staining of the SC appears to be due to exocytosis and exoserosis. Some IF staining also occurs in the upper stratum spinosum. (Magnification x 400.) (C) Same psoriatic lesion as for Figure 4A examined by indirect IF staining for C4. Note comparable indirect IF staining to the direct IF seen in Figure 4B. The same mechanism appears to be responsible. In this specimen the SCAb binding sites appear to be saturated in vivo. (Magnification x 400.)

about half of the hyperkeratotic scales appear to be saturated in vivo (Figures 4A to 4C). Many have at least some “ unsaturated” SCAg combining sites.33 The latter also occurs not uncommonly in other skin lesions (Chapter 7). This may be due to one (or both) of two factors. Notably, anatomic barriers including the vessel walls, the basal layer and/or the prickle cell layer of the epidermis may block passage of serous fluid into the horny layer and thus prevent saturation of SCAg sites. Alternatively, the psoriatic scales may contain both nonreactive and reactive forms of SCAg and only the latter react with SCAb in vivo. Tissue culture studies of psoriatic scales soaked in rabbit sera with high titers of SCAb followed by direct IF staining for rabbit IgG yield

66

Autoimmunity in Psoriasis

FIGURE 4C

Table 2 ELUTION OF SCAb FROM PSORIATIC SCALES Titers of SCAb Tests for SCAb

Indirect IFfc Indirect hemagglutination

Type o f SCAg

Insoluble SCAg Soluble SCAgc

Saline wash“

40