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Epidermolysis bullosa acquisita (EBA) is an autoimmune subepidermal bullous disorder of the skin and mucous membranes. The disease results from the production of immunoglobulin G (IgG) antibodies against type-VII collagen, a major component of anchoring filaments in the dermal-epithelial junction. The disease has two major forms of presentation: the classical (non-inflammatory) type and the inflammatory type. Classical EBA is mainly characterized by the following features: development of non-inflammatory tense blisters on trauma-prone areas, multiple milia cysts, minimal or no inflammation findings on histopathology. Alternatively, inflammatory EBA is defined by widespread inflammatory blistering eruptions and a neutrophil-rich inflammatory infiltrate on standard histopathology. In both cases, specialized immunopathological findings are further required to establish an accurate diagnosis. In this article, we present an atypical case that shares features of both inflammatory and non-inflammatory forms of EBA. The case also serves to review and synthesize current concepts on the etiopathogenesis, diagnosis, and treatment of this extremely rare disease.

Pemphigus is an uncommon autoimmune mucocutaneousblistering disease, mediated by antibodies directedagainst proteins present on the surface of keratinocytesthat provide mechanical structure to the epidermis. Incidencesof the various forms of pemphigus vary fromcountry to country. Pemphigus vulgaris consists of the80% of pemphigus cases and it occurs 10 times morethan pemphigus foliaceus. There have been several recentadvances in the management of pemphigus. Treatmentof with systemic steroids and cytotoxic immunosuppressantscan be highly effective. This article will discussits epidemiology, pathogenesis, clinical variants and approachesto treatment. J Clin Exp Invest 2011; 2 (4): 468-473

The accurate diagnosis of autoimmune bullous diseases of the skin requires evaluation of clinical, histologic, and immunopathologic findings. There is generally a risk of serious side effects or complications in the treatment of autoimmune bullous diseases especially of pemphigus. Therefore definite diagnosis is essential for accurate and effective treatment. Fortunately, there are invaluable laboratory methods such as immunofluorescence tests in confirming a diagnosis that is suspected by clinical examination. In this article, the application techniques of these tests briefly and particularly the immunofluorescence findings that could be obtained in autoimmune bullous diseases were discussed. (Turkderm 2011; 45 Suppl 1: 31-5)

The accurate diagnosis of autoimmune bullous diseases of the skin requires evaluation of clinical, histologic, and immunopathologic findings. There is generally a risk of serious side effects or complications in the treatment of autoimmune bullous diseases especially of pemphigus. Therefore definite diagnosis is essential for accurate and effective treatment. Fortunately, there are invaluable laboratory methods such as immunofluorescence tests in confirming a diagnosis that is suspected by clinical examination. In this article, the application techniques of these tests briefly and particularly the immunofluorescence findings that could be obtained in autoimmune bullous diseases were discussed.

The precise mechanism for acantholysis after pemphigus IgG binds to the cell surface is as yet unknown, although involvement of proteinases such as plasminogen activator (PA) has been suggested. We previously reported that pemphigus IgG, but not normal nor bullous pemphigoid IgGs, caused a transient increase in intracellular calcium ([Ca ++ ] i ) and inositol 1,4,5-trisphosphate (1P 3 ) concentration in cultured DJM-1 cells (a squamous cell carcinoma line). To clarify whether phospholipase C is involved in this process after the antibody binds to the cell surface, we examined the effects of a specific phospholipase C inhibitor (U73122) on the pemphigus IgG-induced increase in [Ca ++ ] i , IP 3 PA secretion, and cell-cell detachment in DJM-1 cells. [Ca ++ ] i and IP 3 contents were determined with or without 30-mm pre-incubation with U73122 or an inactive analogue (U73343) with fura-2 acetoxy-methylester and a specific IP 3 binding protein, respectively. PA activity in the culture medium was measured after various incubation periods with pemphigus IgG by two-step amidolytic assay. The detachment of cell-cell contacts was examined by detecting the retraction of keratin filament bundle from cell- cell contact points to the perinuclear region by immunofluorescence microscopy using anti-keratin antibody. Pemphigus IgG immediately increased [Ca ++ ] and IP 3 content. PA activity in the culture medium has also been increased at 24 h after pemphigus IgG was added in association with cell-cell detachment. However, pre-incubation with U73122 (1-10 µM), but not with U73343 (10 µM), dramatically reduced the pemphigus IgG-induced increases in [Ca + + ] i , IP 3 , and PA activity and inhibited the pemphigus IgG-induced cell-cell detachment. Both U73122 and U73343 cause no effects on cell viability and IgG binding to the cell surface. These results suggest that phopholipase C plays an important role in transmembrane signaling leading to cell-cell detachment exerted by pemphigus IgG binding to the cell surface.

The diagnosis of autoimmune blistering skin disease is increasingly based on the skin antigen(s) that is the target of the autoimmune process. Some patients with bullous diseases have unusual basement membrane autoantibodies that react to antigens present in both the epidermal and dermal sides of skin split with 1 M NaC1. This combined staining pattern is due to antibodies directed in part to a 160-kilodalton (kD) basement membrane antigen present on the epidermal side of the split skin and to different antigen(s) present on the dermal side. The identity of the current antigen(s), and the significance of this unusual type of combined staining antibody response is not known. Sera of five patients with combined staining antibodies, 19 patients with other types of basement membrane antibodies (15 directed only to the epidermal and four only to the dermal side of split skin), and 23 patients without basement membrane antibodies were tested by Western immunoblot for reactivity to 4% sodium dodecyl sulfate + 2 M urea extracts of dermal and epidermal side of salt-split skin. Three (60%) of the combined staining sera had antibodies to an 82–84-kD antigen (p84) reproducibly present in dermal, but not epidermal, extracts of normal human skin. Antibodies to this antigen were absent in the 42 control sera. Western blot affinity-purified antibody to p84 bound only to the basement membrane, on the dermal side of 1 molar salt-split skin. By co-migration experiments, p84 differed from other basement membrane antigens including the major and minor bullous pemphigoid, cicatrizing pemphigoid, and epidermolysis bullosa acquisita antigens, types III and IV collagen, laminin, and epiligrin. Thus, combined staining antibodies are directed in part to an 82–84-kD antigen (p84), a normal but previously undescribed component of the basement membrane of human skin. This antigen differs from the basement membrane antigens recognized by autoantibodies in other subepidermal bullous diseases. The antibody response to p84 provides a specific marker for a novel autoimmune subepidermal blistering skin disease.

As they are potentially life threatening and a significant cause of morbidity, autoimmune bullous diseases have a special place and importance among the other skin disorders. Discovery of autoantibodies of pemphigus and bullous pemphigoid by immunofluorescence techniques and first clinical use of corticosteroids are two major milestones in the history of development processes in diagnosis and treatment of autoimmune bullous diseases in early 1960s. After 1970s with development of new and further research tools led to help us better understand of etiopathogenesis of autoimmune bullous diseases and opened the way of more effective and modern treatment modalities. However, today, the limited number of randomized controlled trials about the effectiveness of certain available drugs using in the treatments of autoimmune bullous diseases is still major problem. In this special issue of Turkderm the epidemiology, etiopathogenesis, diagnosis and treatment of autoimmune bullous diseases are discussed by experienced authors from different dermatology clinics in Turkey. (Turkderm 2011; 45 Suppl 1: 1-2)

Autoimmune bullous diseases, such as bullous pemphigoid or pemphigus vulgaris occasionally develop in psoriatic patients. In a majority of acases, the bullous eruption has been though to be related to antipsoriatic treatment. Three patients with psoriasis and bullous pemphigoid are described. All three had psoriasis for several years when bullous pemphigoid occurre. Two patients had previously been treated for psoriasis with ultraviolet irradiation (UVB) and acitretin and one with local neutral and corticosteroid creams alone for a short period of time. In our experience, the association between psoriasis and autoimmune bullous disease is bassically the result of immune reactions that are not necessarily connected with the antipsoriatic treatment.

Pemphigus vulgaris and pemphigus foliaceus are cutaneous autoimmune diseases characterized by intraepithelial blisters and autoantibodies to desmosomal glycoproteins. The antigens recognized by pemphigus vulgaris and pemphigus foliaceus autoantibodies are desmoglein- 3 (Dsg3) and desmoglein-1 (Dsg1), respectively. Dsg3 and Dsg1 are members of the desmoglein subfamily of the cadherin supergene family of cell adhesion molecules. It has been well documented that a subset of pemphigus vulgaris sera have IgG reactivity to both Dsg1 and Dsg3, suggesting that Dsg1 may also participate in the autoimmune response of these patients. The cellular mechanisms of T cell autoimmunity in these patients, however, are completely unknown. In this study, we tested the proliferative responses of T lymphocytes from eight pemphigus vulgaris patients after incubation with Dsg3 and Dsg1 fusion proteins. The sera of four of these PV patients showed reactivity with both Dsg1 and Dsg3, whereas the remaining four reacted only with Dsg3. We found that T cells obtained from those patients that exhibited the combined Dsg1/Dsg3 autoantibody reactivity showed a proliferative response after exposure to either Dsg1 or Dsg3 fusion proteins. The cellular responses to both of these recombinant proteins were highly specific and restricted to the CD4-positive T cell population. T cells from pemphigus vulgaris patients with no anti-Dsg1 serum reactivity showed a proliferative response to Dsg3, but not to Dsg1. The Dsg1 fusion protein used in this study has minimal sequence homology with Dsg3. Thus, this study provides the first evidence that T cells from a subset of pemphigus vulgaris patients respond to both Dsg1 and Dsg3.

Indirect immunogold electron microscopy studies of cryofixed, freeze-substituted, and post-embedded normal human skin were performed to localize precisely the ultrastructural binding site of circulating autoantibodies from two groups of patients with cicatricial pemphigoid. One group of patients had circulating IgG autoantibodies that bound the dermal side of 1 M NaC1-split skin and immunoprecipitated epiligrin. The other group of patients had circulating IgG autoantibodies directed against the epidermal side of 1 M NaCl-split skin and showed no specific reactivity to any keratinocyte polypeptide by iminunoprecipitation. IgG autoantibodies from all patients with anti-epiligrin cicatricial pemphigoid bound the lowermost aspect of the lamina lucida at its interface with the lamina densa; the greatest staining was seen beneath and beside hemidesinosomes, In contrast, IgG from cicatricial pemphigoid patients whose autoantibodies bound the epidermal side of 1 M NaCl- split skin localized to hemidesmosomes and the junction between hemidesmosoines and the plasma membranes of basal keratinocytes. Although the latter staining pattern is similar to that observed with anti-BPAG2 autoantibodies, sera from our patients with cicatricial pemphigoid did not bind BPAG2 in immunoprecipitation studies of radiolabeled human keratinocyte extracts or show immunoblot reactivity to a fusion protein corresponding to the immunodominant epitope of this polypeptide. These studies demonstrate the following: 1) Autoantibodies from patients with anti-epiligrin cicatricial pemphigoid consistently bind the lower lamina lucida at its interface with the lamina densa; and 2) other patients with the same phenotype may have IgG autoantibodies against yet-unknown epitopes in basal keratinocytes.

International audience; This study describes the presence of antibodies in sera from patients with cicatricial pemphigoid specific for a 168-kDa antigen expressed by buccal mucosa. Six cicatricial pemphigoid sera unreactive, with epidermal or dermal proteins in immunoblot assay were tested on mucosal protein extracts. Four of these sera labeled a mucosal 168-kDa antigen (M168) under reducing conditions. An additional cicatricial pemphigoid serum with circulating antibodies to 180-kDa bullous pemphigoid antigen (BPAg2) also labeled M168. None of these cicatricial pemphigoid sera reacted with the alpha, beta, or gamma subunits of laminin-5. Nitrocellulose elution studies showed that the M168 antigen is a basement membrane antigen and labeled the epidermal side of salt-split skin. Immunoaffinity-purified anti-M168 antibodies did not bind to the 230-kDa bullous pemphigoid antigen (BPAg1) or to the 180-kDa BPAg2. None of the control sera from healthy individuals or from bullous pemphigoid, pemphigus vulgaris, or pemphigus foliaceus patients reacted with Ml68. This study demonstrates the specificity of some cicatricial pemphigoid sera against a 168-kDa antigen that is different from the laminin-5 subunits and shares no epitopes with the antigens of bullous pemphigoid (BPAg1, BPAg2) or the epidermolysis bullosa acquisita.This study describes the presence of antibodies in sera from patients with cicatricial pemphigoid specific for a 168-kDa antigen expressed by buccal mucosa. Six cicatricial pemphigoid sera unreactive, with epidermal or dermal proteins in immunoblot assay were tested on mucosal protein extracts. Four of these sera labeled a mucosal 168-kDa antigen (M168) under reducing conditions. An additional cicatricial pemphigoid serum with circulating antibodies to 180-kDa bullous pemphigoid antigen (BPAg2) also labeled M168. None of these cicatricial pemphigoid sera reacted with the alpha, beta, or gamma subunits of laminin-5. Nitrocellulose elution studies showed that the M168 antigen is a basement membrane antigen and labeled the epidermal side of salt-split skin. Immunoaffinity-purified anti-M168 antibodies did not bind to the 230-kDa bullous pemphigoid antigen (BPAg1) or to the 180-kDa BPAg2. None of the control sera from healthy individuals or from bullous pemphigoid, pemphigus vulgaris, or pemphigus foliaceus patients reacted with Ml68. This study demonstrates the specificity of some cicatricial pemphigoid sera against a 168-kDa antigen that is different from the laminin-5 subunits and shares no epitopes with the antigens of bullous pemphigoid (BPAg1, BPAg2) or the epidermolysis bullosa acquisita.

Epidermolysis bullosa simplex (EBS) is a mechano-bullous disorder characterized by intraepidermal blistering within the basal keratinocytes as a result of trauma to the skin. As part of the DNA diagnostics program, our laboratory has analyzed a cohort of 57 patients with the initial referral diagnosis of EBS. Among these patients, 18 were found to harbor heterozygous mutations in the keratin 5 or keratin 14 genes, KRT5 and KRT14, respectively, whereas in 14 cases, the disease was associated with mutations in both alleles of the plectin gene. Among the keratin mutations, 12 were distinct and six were novel, and in most cases there was no family history of a blistering disease. Prenatal diagnosis of eight pregnancies with keratin gene mutations, at risk for EBS either because one of the parents was affected (three cases) or history of a previously affected child as a result of a de novo mutation (five cases), predicted two fetuses being affected and six being normal. No recurrence of the de novo mutations in these pregnancies was disclosed. Collectively, the data suggest that a significant number of cases diagnosed as EBS are due to plectin mutations, and many cases result from de novo mutations in KRT5 and KRT14 genes. These findings have implications for genetic counseling and prenatal diagnosis for EBS.