Direct immunofluorescent study of the skin on occurrence of complement in pemphigus

Differential gene expression levels might explain association of LAIR2 polymorphisms with pemphigus

The leukocyte-associated immunoglobulin-like receptor 1 (LAIR-1) is a collagen-binding inhibitory receptor important for the regulation of immune responses, expressed on the majority of peripheral blood mononuclear cells (PBMC). LAIR-2 is a soluble homolog that antagonizes LAIR-1 inhibitory function by binding the same ligands. We sought to investigate whether LAIR1 and LAIR2 single nucleotide polymorphisms (SNP) are associated with differential mRNA expression levels. We analyzed 14 SNPs of LAIR1 (6) and LAIR2 (8) by mass spectrometry-based genotyping and extracted mRNA from PBMC of 177 healthy subjects, followed by quantitative assays. Four SNPs of LAIR1 and two SNPs of LAIR2 mark differential mRNA levels in healthy individuals. To verify the biological relevance of these findings, we analyzed additional 515 individuals (282 patients and 233 controls) to check if LAIR1 and LAIR2 differential mRNA expression could be related to susceptibility to pemphigus foliaceus (PF), an autoimmune blistering skin disease endemic in Brazil. Two LAIR1 variants (rs56802430 G, OR = 1.52, p = 0.0329; rs11084332 C, OR = 0.57, p = 0.0022) and one LAIR2 (rs2287828 T+, OR = 1.9, p = 0.0097) contribute to differential susceptibility to PF. Furthermore, we demonstrate interactions among four LAIR2 SNPs (rs2042287, rs2287828, rs2277974 and rs114834145). A haplotype harboring these SNPs is strongly associated with higher LAIR2 mRNA levels (4.5-fold, p = 0.0069) and with higher susceptibility to PF (OR = 4.02, p = 0.0008). We suggest that LAIR1 and LAIR2 genetic variants are associated with regulation of gene expression and variable PF susceptibility, and show indirect association of LAIR2 differential mRNA expression with PF pathogenesis. Our data demonstrate how this relatively unknown disease can add invaluable knowledge regarding the role of LAIR1 and LAIR2 in immune responses.

Dermatoses bolhosas auto-imunes

Dermatoses bolhosas autoimunes são doenças cuja manifestação cutânea primária e fundamental consiste em vesículas e bolhas. Classificam-se conforme a localização da bolha, em intraepidérmica e subepidérmica. Os pacientes produzem autoanticorpos contra estruturas específicas da pele detectáveis por técnicas de imunofluorescência, immunobloting e Elisa. Os recentes avanços da biologia molecular e celular têm permitido conhecer esses autoantígenos, contra os quais os pacientes se sensibilizam e que estão localizados na epiderme ou na junção dermoepidérmica. São doenças de baixa incidência, porém de elevada morbidade e por vezes letais. O objetivo deste trabalho é revisar e descrever os progressos nos conhecimentos de quatro doenças vésico-bolhosas autoimunes: pênfigo foliáceo endêmico (fogo selvagem), pênfigo vulgar, penfigóide bolhoso e dermatite herpetiforme.

Immunofluorescence in dermatology

The accurate diagnosis of bullous and other immune diseases of the skin requires evaluation of clinical, histologic, and immunofluorescence findings. Immunofluorescence testing is invaluable in confirming a diagnosis that is suspected by clinical or histologic examination. This is especially true in subepidermal bullous diseases that often have overlap in the clinical and histologic findings. Direct immunofluorescence is performed on perilesional skin for patients with bullous diseases and lesional skin for patients with connective tissue diseases and vasculitis.

Further support for a role for Th2-like cytokines in blister formation of pemphigus

Pemphigus vulgaris and pemphigus foliaceus are commonly known as antibody-mediated bullous diseases. However, recently a role for infiltrating cells as contributors to the pathogenesis of these diseases has been suggested. The aims of our study were to characterize the immunophenotype of the cellular infiltrate of pemphigus lesional skin and to study the cytokines secreted. We have therefore performed an immunohistochemical study with a large panel of monoclonal antibodies (to CD3, CD4, CD8, CD25, CD30, myeloperoxidase, eosinophil cationic protein EG2, tryptase, human interleukin (IL)-2, human IL-4, human IL-5, human IL-6, human IL-8, and interferon (IFN)-gamma using the alkaline phosphatase-antialkaline phosphatase procedure on lesional and uninvolved skin of six patients with clinical, histological, and immunofluorescent proven pemphigus. We also performed RT-PCR in order to demonstrate mRNA expression of the cytokines of interest. Our results suggest the presence of a T cell population with a prevalent Th2-like cytokine pattern in lesional skin. In addition, we demonstrate a consistent number of granulocytes and mast cells that show clear signs of activation. These data suggest the involvement of an inflammatory infiltrate in the production of pemphigus lesions. In particular, we assume that Th2 cells may be implicated in the very early stages of autoimmune response, concluding that they exert broad activity in blister formation.

Expression of CD1 and HLA-DR by Langerhans cells (LC) in oral lichenoid drug eruptions (LDE) and idiopathic oral lichen planus (LP)

Numbers of Langerhans cells (LC) expressing the common thymocyte antigen (T6/CD1) are similar in oral lichen planus (LP) and in normal oral epithelium; however, expression of class II major histocompatibility antigens (HLA-DR/Ia) by Langerhans cells is greater in lichen planus than in normal epithelium, a phenomenon believed to be associated with activation and antigen presentation. This study quantified the numbers of T6+ve and HLA-DR + ve Langerhans cells in oral lichen planus and lichenoid drug eruptions (LDE) to investigate whether differences may reflect differing routes of antigen presentation. Six patients with oral lichenoid drug eruptions and six control idiopathic oral lichen planus patients had lesional biopsies. An immunoperoxidase technique was used to demonstrate binding of T6 and HLA-DR antibodies to identify dendritic intraepithelial cells as Langerhans cells and activated Langerhans cells, respectively. In lichenoid drug eruptions, the number of HLA-DR + ve LC was significantly lower than the number of T6 + ve LC (P < 0.05), whereas in idiopathic lichen planus the numbers of T6 + ve and HLA-DR + ve LC did not differ significantly (P = 0.20). The results provide evidence for differences in the routes of antigen presentation in lichenoid drug eruptions and idiopathic lichen planus.

Immunofluorescence study of pemphigus from north India

Both serum studies by indirect immunofluorescence (IIF) tests and skin biopsy examination by direct immunofluorescence (DIF) were performed on 22 cases of pemphigus with clinically active lesions. Twenty cases had pemphigus vulgaris and two, pemphigus foliaceus. The majority of cases (70%) were between 21 and 60 years old; the mean age was 39.5 +/- 12.7 years. There was no sex predilection. DIF showed the positive fluorescence of intercellular cement substance (ICS) of the epidermis in all 22 cases (100%). IgG was positive in 77.2%, followed sequentially by C3C (50%), IgA (45.45%), and IgM (36.36%). Six cases (27.27%) also showed granular immunoglobulin and/or complement deposits at the dermoepidermal junction. IIF detected serum antiepithelial antibodies in 18 cases (81.81%) using human esophagus as substrate. Most of these cases (88.88%) showed IgG type of antibodies; the other 11.11% exhibited IgA and IgM in low concentrations. 1+ titer positivity was observed in 15 cases. This study demonstrates the value of DIF for a definitive diagnosis of pemphigus. However, it is also important to appreciate that immunofluorescence is not a substitute for histopathology, but rather complementary to it.

Basal cell cytoplasmic autoantibodies in oral lichenoid reactions

One hundred sixty-one patients with a clinical diagnosis of an oral lichenoid reaction were evaluated serologically for circulating autoantibodies toward basal cell membrane components. The study group comprised 119 women and 42 men with a median age of 59 and 55 years, respectively. Most patients (n = 144) had an oral mucosal biopsy undertaken. Serologic investigation aimed to identify an IgG antibody that, under immunofluorescent staining, produced an annular fluorescence of basal cells and that has been referred to as basal cell cytoplasmic antibody. These basal cell cytoplasmic antibodies were significantly associated with systemic drug usage, histologic diagnosis of a lichenoid reaction, and a unilateral intraoral distribution of the clinical lesion. In the diagnosis of oral lichenoid reactions precipitated by drug therapy, the basal cell cytoplasmic phenomenon may be a useful adjunct to clinical and histologic investigation.

Granulocyte activation in bullous diseases: release of granular proteins in bullous pemphigoid and pemphigus vulgaris

BACKGROUND

Eosinophil and polymorphonuclear granulocytes may be involved in the formation of blisters in bullous dermatoses, particularly bullous pemphigoid.

OBJECTIVE

Our purpose was to evaluate the role of granulocyte activation in the pathogenesis of pemphigus vulgaris and bullous pemphigoid.

METHODS

Levels of eosinophil cationic protein (ECP) and neutrophil-derived myeloperoxidase (MPO) in blister fluid and serum and levels of serum IgE were determined in patients with bullous pemphigoid (n = 12), those with pemphigus vulgaris (n = 9) and healthy volunteers (n = 12).

RESULTS

In blister fluid and serum of patients with bullous pemphigoid, significantly elevated concentrations of ECP, MPO and IgE were detected as compared with controls. In contrast, ECP, MPO, and IgE levels in blister fluid and serum of patients with pemphigus vulgaris did not significantly differ from controls. Moreover, the MPO/ECP ratio in serum of patients with bullous pemphigoid was significantly decreased as compared with controls, whereas the MPO/ECP ratio in pemphigus vulgaris did not differ from controls, indicating a preferential activation of eosinophils in bullous pemphigoid only. In patients with bullous pemphigoid, serum levels of ECP and MPO significantly decreased during immunosuppressive therapy to levels similar to those of controls.

CONCLUSION

Activated granulocytes, releasing their granular contents such as ECP and MPO, may be of importance for blister formation in bullous pemphigoid and may be useful for monitoring disease activity.

Subclass distribution of human IgG autoantibodies in pemphigus

The distribution of IgG subclasses in the intercellular substance (ICS) reactive autoantibodies in serum of 10 patients with pemphigus was analyzed by semiquantitative indirect immunofluorescence (IF) using the HP series of monoclonal antibodies specific for the four human IgG subclasses. IgG4 ICS specific autoantibody was present in all 10 sera at a titer of 10 to 320, while IgG1 antibodies were found in 9 of 10 sera at a seemingly lower level. IgG3 autoantibodies were detected in the serum of one patient, only after isolation of IgG using ion-exchange chromatography. Autoantibodies of IgG subclass 2 were not detectable in any of the 10 sera tested. One of the ten patients displayed circulating anti-ICS antibodies of only the IgG4 isotype.

Complement fixation by pemphigus antibody. III. Altered epidermal cell membrane integrity mediated by pemphigus antibody and complement

The present study investigates the effects of pemphigus IgG and complement upon cell viability and/or membrane integrity using trypan blue exclusion, ethidium bromide (EB) staining, and fluorescein diacetate (FDA) conversion by living cells. Forty-eight-hour cultivated epidermal monolayers of neonatal BALB/c mice were incubated in media containing 1 mg/ml purified pemphigus IgG for 48 h in either the presence or absence of complement (absorbed AB sera). Adherent and detached cells were examined by both phase and fluorescence microscopy. Results from trypan blue exclusion showed that pemphigus IgG plus complement produced a modest decrease in exclusion of the dye compared to pemphigus IgG without complement. When FDA/EB comparisons were made, however, the differences were more substantial. When complement plus pemphigus IgG was added to cultures, the number of FDA-positive adherent cells decreased significantly and the number of EB-positive detached cells increased significantly. The effects of complement were inhibited by the use of heat-inactivated AB sera or by C1q depletion of AB sera. No significant effect on the cells was observed in the presence or absence of complement when pemphigus F(ab')2 fragments or when normal IgG was used. Plasminogen depletion of the complement source did not interfere with complement and pemphigus IgG effects as judged by the FDA/EB assay. These studies suggest that pemphigus antibody in the presence of complement alters cell membrane integrity and supports the contention that complement may play a significant role in the mechanism of acantholysis.

Immunopathologic mechanisms in pemphigus and bullous pemphigoid

Pemphigus and bullous pemphigoid are autoimmune bullous diseases of the skin. Pemphigus, an intraepidermal blistering disease, is characterized by autoantibodies reactive with antigens located in the intercellular spaces or on the surfaces of epidermal cells. These antibodies, which have recently been shown to activate complement, appear to be the cause of the basic pathologic process of pemphigus, acantholysis. The complement system and the plasminogen-plasmin system may be important mediators in the detachment of epidermal cells. Bullous pemphigoid, a subepidermal blistering disease, is characterized by autoantibodies reactive with an antigen located in the lamina lucida region of the basement membrane zone. These autoantibodies, which will avidly fix complement, appear to mediate subepidermal separation by attraction of a variety of inflammatory cells. Anaphylatoxins, released by activation of C4 and C3, or specific IgE antibodies, may activate mast cells with release of ECF-A attracting eosinophils. With activation of C5, C5a is released which could attract polymorphonuclear leukocytes. Antigen-specific lymphocytes, which can also contribute histamine releasing substances, may also be involved. The exact mechanism by which the epidermis separates from the dermis in bullous pemphigoid, however, remains unresolved.

Complement fixation by pemphigus antibody. I. In vitro fixation to organ and tissue culture skin

Although complement is often detected in the intercellular substance of pemphigus skin lesions, the ability of pemphigus antibodies to fix complement in vitro is controversial. The purpose of this study was to test in vitro complement fixation abilities of pemphigus antibodies further using organ and tissue culture methods. Epidermal cell monolayers from mouse tail were incubated with the purified IgG fraction of pemphigus serum followed by purified Clq. Binding of Clq, as well as IgG was demonstrated by immunofluorescence methods. When purified Clq was replaced with normal human serum as a complement source, positive C3 and C4 staining were also evident. When purified IgG of normal human serum was used in place of pemphigus IgG, similar immunofluorescence staining was not observed. Further evidence for complement fixation in vitro by pemphigus antibodies was obtained using organ cultures. Organ culture of normal human skin and monkey esophageal mucosa cultured in purified pemphigus IgG showed intercellular substance binding of IgG. No binding was observed when normal IgG was substituted for pemphigus IgG. Additional organ culture sections were then treated with complement (fresh normal human serum) and tested by in vitro complement staining. Fixation of Clq, C4, and C3 was noted in intercellular substance areas of organ cultured skin and mucosa incubated with pemphigus IgG but not those incubated with normal IgG. Prior treatment of pemphigus IgG organ cultured skin sections with unlabeled anti-C3, blocked positive C3 staining. These results suggest that some pemphigus antibodies are capable of activating complement in vitro.

Pemphigus vegetans. Neumann type and Hallopeau type

Two cases of pemphigus vegetans are presented, one of the Neumann type and one of the Hallopeau type. The differences between the two subsets are clinical presentation and course. Patients with the Hallopeau type often have a relatively benign disease, require lower doses of systemic corticosteroids, and usually have a prolonged remission. Patients with the Neumann type have a course similar to pemphigus vulgaris, need higher doses of systemic corticosteroids, and have relapses and remissions. The histologic findings in the vegetating lesions are similar in both types. The immunopathologic features of both types are indistinguishable and similar to pemphigus vulgaris. IgM staining of eosinophilic microabscesses was observed in one case.

Persistent vegetating and keratotic lesions in patients with pemphigus vulgaris during immunosuppressive therapy

We describe three patients with pemphigus vulgaris, who during treatment with low doses of immunosuppressive drugs developed persistent keratotic or vegetating skin lesions. Direct immunofluorescence (IF) examination of these lesions showed the typical findings of pemphigus.

Mechanism of lesion production in pemphigus and pemphigoid

Current evidence strongly supports the theory that the lesions of pemphigus are due to binding of pemphigus antibody to an antigen in or near the epidermal cell membrane, which causes a release of at least one enzyme which results in dissolution of the intercellular attachments and acantholysis. Similarly, strong evidence supports the hypothesis that pemphigoid blisters are due to binding of antibody at the basement membrane, followed by activation of complement and release of anaphylatoxins which activate tissue mast cells to release eosinophil chemotactic factor. These eosinophils then release tissue-destructive enzymes and reactive oxygen intermediates directly onto the basement membrane zone, with loss of dermoepidermal adherence and formation of blisters.

Antibody-induced proteinase activation: a proposed mechanism for pemphigus

The current state of understanding of pemphigus includes the following: 1. Pemphigus is an autoimmune disease. In all variants a circulating autoantibody is found which binds to epidermal cells. In vivo antibody may be found deposited in the epidermis of patients. 2. The autoantibody levels generally correlate with disease activity indicating a relationship between antibody and clinical disease. 3. Although complement components are found in lesional skin, complement does not appear to be necessary for dissolution of the epidermal cement substance. 4. The treatment of pemphigus with corticosteroids has drastically reduced mortality rates. 5. Three different groups have presented results in two different experimental systems which indicate that subsequent to binding of pemphigus antibody to epidermal cells a proteinase is activated. This proteinase(s) degrades the intercellular cement substance of epidermis which results in loss of cellular adhesion and acantholysis. There are numerous questions still remaining. What is the nature of the proteinase(s) and the surface protein(s) it cleaves? Does the binding of pemphigus antibody to the cell surface induce enzyme synthesis, specific enzyme activation, or generalized lysosomal secretion? The answers to these questions will have broad biologic relevance since they may elucidate the role of anticell surface antibodies in disease states.

Drug-induced anogenital cicatricial pemphigoid

A case of cicatricial pemphigoid (CP) with a rare primary localization on the mucosal surfaces of the anus and the vulva and on perianal skin, associated with long-term therapy with clonidine, is described. Direct immunofluorescence investigation of lesional skin suggests possible complement mediated tissue injury in between basement membrane and epidermal basal cells. The possibility is discussed that drug induced metabolic disturbance (cyclic AMP-system) at a local level at the site of the basal cells might lead to the formation of immunogens and be one of the initiating factors in subepidermal bullous immune dermatoses. It is concluded that in cases of cicatricial pemphigoid the use of drugs must be considered as one of the aetiological possibilities.

Immunofluorescence studies across the leprosy spectrum

Forty biopsies from skin lesions of untreated (24) and treated (16) leprosy patients, representing the whole leprosy spectrum, were examined by means of immunofluorescence (IF) methods. Only few or no cells staining with FTC-labelled antihuman immunoglobulin antisera were found in the lesional skin of all patients examined. Sparse IgM-deposits along the basement membrane of the epidermis were observed in a few borderline lepromatous and lepromatous patients. Complement deposits along the basement membrane of the epidermis and in the vessel walls were found in tuberculoïd as well as in lepromatous patients. Complement and in a lesser number IgG-deposits were observed around sweat glands and sometimes around sweat gland ducts and other skin appendages. Autofluorescing macrophages were noted in patients at the lepromatous side of the leprosy spectrum; approximately half of these patients showed complement deposits in an around these cells.

Immunofluorescence studies in reactional leprosy with relevance to treatment

Twenty-three biopsies of skin lesions of patients with various types of leprosy, showing a recent reaction, were examined by means of immunofluorescence (IF) methods. The patients were divided into two groups according to the number of inflammatory cells, staining with various FTC-labelled anti-immunoglobulin antisera, in representative areas of the biopsies. It was found that the presence of these cells was correlated with a good response to thalidomide treatment.

Autoimmunity in psoriasis. A complement immunofluorescence study

The stratum corneum (SC) antibodies are present in all human sera as seen by indirect immunofluorescent (IF) staining. They appear to bind in vivo to the stratum corneum of psoriatic lesions. They fix complement in vitro in a two step complement IF test system using either anti C4 or anti C3 conjugates as indicators. IF tests with proper controls showed that the SC antigen in psoriatic scales is coated not only with IgG but in a majority of the lesions also with complement. In the present studies in fully developed lesions complement was detectable in 88% of the specimens studies and in about 50% of very fresh linear lesions of unintentional Köbner type. These as well as some previously published observations afford indirect evidence for the participation of SC antibodies and the ensuing fixation of complement in the development of psoriatic lesions.

Absence of intercellular antigens in the deep layers of the epidermis in pemphigus foliaceus

12 patients with pemphigus foliaceus, a form of pemphigus with lesions that arise in the intercellular substance in the superficial layers of the epidermis, and 7 patients with pemphigus vulgaris, where lesions are in the deep layers, were studied by immunofluorescence. Circulating antibodies to intercellular antigens (IC antibodies) were found in 11 pemphigus foliaceus and 5 pemphigus vulgaris patients. On direct immunofluorescence of skin lesions 75% (9 of 12), pemphigus foliaceus patients had intercellular deposits of IgG localized solely or predominantly in the superficial epidermal layers, whereas this was not the case in any of the patients with pemphigus vulgaris. Over 70% of the pemphigus foliaceus patients with predominantly superficial IgG deposits lacked in their lesions normal intercellular antigens usually expressed in the deep layers of the epidermis. This was shown by the inability of IC antibodies in autologous or allogeneic sera to bind to intercellular antigens in the lower epidermis of patient's skin, even though the same sera could bind to intercellular antigens in all layers of normal allogeneic skin. Lack of normal intercellular antigens deep in the epidermis may result in circulating IC antibodies binding to the superficial layers, a site which corresponds to, and thus in some patients may account for, the anatomical location of lesions in pemphigus foliaceus.

Capability of complement fixation of pemphigus antibodies in vitro

The capability of complement fixation of pemphigus antibodies was tested using combined in vitro complement immunofluorescent (IF) staining methods. Three sera out of 25 serum samples from 22 pemphigus patients revealed positive reactions, while all other sera gave negative results. Specificity control tests confirmed the positive reactions to be specific for complement staining. Complement fixing pemphigus antibodies were titrated lower than corresponding IgG antibodies and were demonstrable only in the extensive stage of the disease. Thus, the present work supplied evidence that pemphigus antibodies fix complement in vitro. However, the discrepancy still remains between the in vivo deposition of complement in most cases of pemphigus and in vitro capability of complement fixation in only few cases. More investigations should be needed to explain the exact role of complement in pemphigus acantholysis.

Ocular cicatricial pemphigoid associated with practolol therapy

The clinical and laboratory findings in a case of serious cicatricial blistering of the ocular mucous membrane were comparable with those found in cicatricial pemphigoid (ocular mucous membrane pemphigoid).

Complement in pemphigus vulgaris and other bullous dermatoses

The behavior of the complement and of its components C4 and C3 has been studied in serum and in blister fluid both in patients with pemphigus vulgaris and other bullous dermatoses and in healthy subjects with experimentally induced blisters. The results are suggestive of local activation of the complement, in the blister fluid of patients with pemphigus vulgaris, pemphigus erythematosus and bullous pemphigoid according to the classical enzymatic sequence.

Immunofluorescent investigations in cutaneous vasculitis. I. Histotopical demonstration of complement/complement factors

Using an indirect double layer immunofluorescence method, fresh skin lesions of 10 patients with different forms of cutaneous vasculitis were tested for the occurrence of complement-factors C1q (C1), alpha2D(C3) and beta1F (C5). In contrast to the irregularly found complement fixing immunoglobulins IgG and IgM, complement could be regularly seen bound to the cutaneous vessel walls; mostly the C3-factor alpha2D. C1q was demonstrable, combined with IgG and/or IgM only in 2 cases. In 5 patients there was a non-homogenous, roddy fluorescenece of the epidermal basal membrane zone and the cutaneous vessels, when alpha2D or beta1F were tested. Our findings suggest that the "alternate pathway" beginning with C3-activation is followed in most cases, whereas a typical "immune complex vasculitis" is obviously rare. The constant occurrence of complement in the cutaneous vessel walls of vascultis lesions is consistent with the known chemotactic and destructive role of complement factors in experimental models of angiitis, but it may not necessarily involve a specific immunological process.

Cutaneous immunopathology: recent observations

Immunofluorescent studies are currently being done on patients with pemphigus, pemphigoid, dermatitis, lupus erythematosus and its variants, the cutaneous prophyrias, scarring alopecia, erosive mouth lesions, light-sensitive disorders, and cutaneous vasculitis. In this paper I shall review some of the recent advances in immunopathology and report the results that have been obtained in our laboratory.

Complement activation in bullous skin diseases

Pemphigus, bullous pemphigoid, cicatricial pemphigoid, dermatitis herpetiformis, and herpes gestationis are members of the chronic vesiculobullous skin diseases of man. The complement system, including both the classical and alternative pathways, may be important in the pathogenesis of these diseases. In pemphigus, early complement components (C1, C4, and C2) appear to be activated in addition to later components (C3 and C5), suggestive of classical pathway activation. Participation of properdin in addition to early complement components suggests local activation of both complement pathways in bullous pemphigoid and cicatricial pemphigoid. Herpes gestationis and dermatitis herpetiformis may be bullous skin diseases entirely mediated by the alternate or properdin pathway. The specific immunopathologic findings in these diseases are discussed.