Coexistence of pemphigus foliaceus and bullous pemphigoid. Demonstration of autoantibodies that bind to both the pemphigus foliaceus antigen complex and the bullous pemphigoid antigen

Pemphigus and bullous pemphigoid are autoimmune blistering diseases of the skin characterized by circulating autoantibodies directed against the keratinocyte cell surface and the epidermal basement membrane zone, respectively. The coexistence of pemphigus and bullous pemphigoid is very uncommon. We describe a patient with pemphigus foliaceus who later developed bullous pemphigoid and show, by means of immunoprecipitation studies utilizing both cultured keratinocytes and suction blister epidermis, that our patient had circulating autoantibodies directed against both the pemphigus foliaceus antigen complex and the bullous pemphigoid antigen. This report is the first to demonstrate the coexistence of pemphigus foliaceus and bullous pemphigoid at the molecular level.     

Blistering diseases in the mature patient

Autoimmune blistering diseases (AIBD) are a group of chronic diseases affecting the skin and mucous membranes, with different presentation, clinical course, histologic and immunopathologic findings, and different therapeutic approach. Blisters develop as a result of autoantibodies directed against distinct adhesion structures within desmosomes or within the basement membrane zone. The most common AIBD that develops in the elderly is bullous pemphigoid (previously also named “pemphigoid senilis”), but mature patients can also present with other AIBD as mucous membrane pemphigoid, epidermolysis bullosa acquisita, paraneoplastic pemphigus, pemphigus vulgaris, pemphigus foliaceus, linear IgA dermatosis, and dermatitis herpetiformis. There are no differences in treatment approach to mature patients with AIBD, but due to more common comorbidities, systemic therapy should be given with more caution and control, and due to distorted skin integrity in the aged skin, the safety concerns are increased with the long-term use of any topical medication.     

Bovine gingival lysate: a novel substrate for rapid diagnosis of autoimmune vesiculo-bullous diseases. A preliminary observation

Immunoblot assays have been developed to characterize the autoantigens and to detect autoantibodies in muco-cutaneous autoimmune vesiculo-bullous diseases using different substrates. However the results have been inconsistent, because availability and standardization of different substrates has been a major problem. The aim of this study was to develop an immunoblot assay using bovine gingival lysate as substrate because it is easily and readily available as well as inexpensive. Sera from patients with different vesiculo-bullous diseases were studied. These included 25 patients with pemphigus vulgaris (PV), 8 with paraneoplastic pemphigus (PNP), 12 with pemphigus foliaceus (PF), 25 with bullous pemphigoid (BP), and 22 with cicatricial pemphigoid (CP). Serum samples from 40 normal human volunteers were also studied. The autoantibody titers were determined based on the binding pattern of each disease and compared to those obtained by routine indirect immunofluorescence (IIF). Our observations suggest that the titers from immunoblot assays were significantly higher than titers obtained by IIF (P<0.0001). When the autoantibody titers were compared using bovine gingival lysate and human epidermal lysate as substrate, statistically significant differences were not observed. The use of bovine gingival lysate as a substrate will facilitate the rapid and early serological diagnosis of patients with vesiculobullous diseases. It may also be of benefit to laboratory investigators studying these autoantibodies.     

Frequency of IgA antibodies in pemphigus, bullous pemphigoid and mucous membrane pemphigoid

Circulating and bound IgA antibodies can be found in the autoimmune blistering diseases, but their prevalence, clinical relevance and target antigens remain unknown. Thirty-two patients with pemphigus, 73 with bullous pemphigoid and 28 with mucous membrane pemphigoid were studied retrospectively. Direct immunofluorescence (DIF) analysis of IgG, IgA, IgM and C3 was carried out for all cases. Sera were studied by standard indirect immunofluorescence, indirect immunofluorescence on salt-split skin, immunoblotting for bullous pemphigoid and mucous membrane pemphigoid and ELISA for pemphigus. With DIF, we found IgA autoantibodies in 22 of all 133 cases. Circulating IgA antibodies to skin were detected in 2 of 3 IgA-DIF-positive patients with pemphigus, in 3 of 6 with bullous pemphigoid, and in 6 of 13 with mucous membrane pemphigoid. We confirm that the IgA reactivity is more frequently associated with mucous membrane involvement, especially in cases without critical involvement (5/8). The role of IgA and its antigenic specificity in these diseases remain unclear.     

Non‐infectious ulcerating oral mucous membrane diseases

Non‐infectious ulcerative oral mucous membrane diseases are difficult to separate at first glance: they can appear as aphthous, bullous, lichenoid, drug‐induced or toxic‐irritative reactions. The overall considerations of history, localization of lesions, clinical and histological features, as well as direct and indirect immunofluorescence examination are required for the correct diagnosis. Some disorders start preferably at the oral mucosa, like pemphigus vulgaris and Adamantiades‐Behçet disease, while others, such as cicatricial pemphigoid and habitual aphthosis generally are confined to the mucous membranes. This overview summarizes clinical and diagnostic features, differential diagnoses and current therapeutic possibilities of non‐infectious inflammatory stom‐atopathies, which possess a specific position among skin diseases in distinction to infectious or neoplastic oral ulcers. This group of diseases includes aphthous lesions, lichen planus mucosae, lupus erythematosus, disorders with intraepi‐dermal or subepidermal formation of blisters including pemphigus, bullous pemphigoid, erythema multiforme and variants as well as allergic or toxic contact stomatitis.     

Eosinophilic spongiosis

This report gives an account of nine patients, all females, with the histological finding of eosinophilic spongiosis. Six of them had positive intercellular antibodies on direct immunofluorescence but only two had circulating pemphigus antibodies. The clinical presentations of those with proven pemphigus resembled bullous pemphigoid in one, dermatitis herpetiformis in another, whereas the remainder were more typical of pemphigus foliaceus or vulgaris. Three patients had negative immunofluorescence. They may still develop pemphigus or alternatively could have some unclassifiable bullous dermatosis.     

Schleimhautbeteiligung bei blasenbildenden Autoimmunerkrankungen

Autoimmune bullous diseases are characterized by intraepidermal or subepidermal autoantibody deposition that leads to blisters and secondary erosion. Mucous membranes are frequently affected in pemphigus vulgaris and always involved in cicatricial and mucosal pemphigoid. Mucosal lesions are detected less frequently in patients with bullous pemphigoid or epidermolysis bullosa acquisita. The diagnosis of autoimmune bullous disorders is based on determination of the subtype of autoantibodies bound in the skin and the clinical picture. Treatment is based on immunosuppression related to the type of disease and severity of the mucosal symptoms. Ocular involvement in mucosal pemphigoid and pemphigus vulgaris requires systemic treatment.     

Efficacy of Dapsone in the Treatment of Pemphigus and Pemphigoid

Dapsone is a chemotherapeutic agent primarily used in treating leprosy, Pneumocystis jiroveci(previously carinii) pneumonia, and malaria. It is also used as an adjuvant in the treatment of pemphigus and pemphigoid. To assess the role of dapsone in the treatment of pemphigus and pemphigoid, a retrospective review of reports in the English-language literature was conducted. Information on the number of patients treated, their average age, prior therapies, indications for use, protocol (dose and interval) used, concomitant therapies, reported adverse effects, and clinical outcomes were analyzed. There were 35 case reports/series published describing the use of dapsone in a total of 427 patients. Data on 55 pemphigus patients were obtained from several case reports and some case series and one randomized controlled trial. Of these, 32 patients with pemphigus vulgaris and 14 patients with pemphigus foliaceus responded to dapsone. Data from 13 case series, each including at least five patients, accounted for 372 patients with pemphigoid. The overall response rates to dapsone, when given either alone or in combination with corticosteroids or immunosuppressive agents, were 84% in mucous membrane pemphigoid, and 81% in bullous pemphigoid. Hemolysis was the most common adverse effect observed. Dapsone is a promising and useful agent in patients with autoimmune mucocutaneous blistering diseases, especially in mucous membrane pemphigoid. It can be used as a corticosteroid-sparing agent. Therefore, its combined use with oral corticosteroids may be useful in pemphigus vulgaris and bullous pemphigoid. Adverse effects of dapsone are dose dependent and usually reversible. Hemolysis and concomitant anemia secondary to hemolysis are expected in most patients. In the opinion of the authors, dapsone is underutilized in the treatment of autoimmune mucocutaneous blistering diseases.     

Immunopathology of oral mucosal inflammatory diseases*

We have reviewed the results of the direct immunofluorescence test performed on oral mucosal biopsy specimens since June 1973. During this period, immunopathological examinations were performed extensively to confirm clinical impressions and to provide insight into the pathogenesis of the bullous, erosive and ulcerative diseases affecting the oral mucosa. Early diagnosis of these diseases was afforded with the adjunctive use of direct immunofluorescence examinations. Diagnostic accuracy was excellent. The direct immunofluorescence test was positive in 15 15 specimens of pemphigus vulgaris, 33 of bullous pemphigoid, 22 of lupus erythemaicsus and 19,22 of cicatricial pemphigoid. Patients with desquamative gingivitis could be classified as‘cicatricial pemphigoid suspects' by this examination, and 5/6 of these patients have evolved into cicatricial pemphigoid. No diagnostic pattern was noted for lichen planus. False positive examinations were not apparent among the 124 specimens examined.     

Serum plakophilin‐3 autoreactivity in paraneoplastic pemphigus

Summary Background Paraneoplastic pemphigus (PNP) is a malignancy‐associated autoimmune disease in which circulating autoantibodies recognize various polypeptides that constitute the desmosomes and hemidesmosomes of epithelial structures. Objectives To determine whether PNP is associated with autoreactivity against the armadillo‐repeat‐containing plakophilin‐3 (PKP3) protein. Methods HEK293 cells were transiently transfected with either a pEF6/myc‐His or a pEGFP‐N2 construct, both encoding human PKP3 (protein products of 85 kDa and 115 kDa, respectively). Protein lysates were made in Laemmli buffer. The proteins were separated by gel electrophoresis, transferred to filters and probed with five PNP sera, four pemphigus vulgaris sera, two pemphigus foliaceus sera, five bullous pemphigoid sera, one cicatricial pemphigoid serum and one linear IgA dermatosis serum. A mouse monoclonal anti‐PKP3 antibody raised against a 20‐amino acid peptide of human PKP3 was used as a positive control. Results Autoreactivity against both 85‐kDa and 115‐kDa recombinant PKP3 protein products was detected in all five PNP sera and in one pemphigus vulgaris serum. None of the sera of patients with basement membrane zone bullous diseases reacted with the PKP3 protein products. The presence of autoantibodies against PKP3 in PNP sera was subsequently confirmed in human epidermal lysate blots. Conclusions This is the first report of PKP3 reactivity in bullous disorders, which was present in all the PNP sera tested. The presence of PKP3 reactivity in one patient with pemphigus vulgaris is not unexpected as the desmosome is also targeted in this disease.     

Short-time extracorporeal photochemotherapy in the treatment of drug-resistant autoimmune bullous diseases.

BACKGROUND: Bullous pemphigoid (BP) and pemphigus vulgaris (PV) are potentially severe diseases. In drug-resistant PV and pemphigus foliaceus, long-term adjuvant treatment with extracorporeal photochemotherapy (photopheresis, ECP) has been reported to induce remission. Only limited numbers of patients have been reported so far. No information about the effectiveness in drug-resistant BP is available. PATIENTS AND METHODS: Seven patients with drug-resistant autoimmune bullous diseases have been referred to the photopheresis center of Jena (3 x PV, 3 x BP, 1 x pemphigus foliaceus). The age ranged from 31 to 85 years. ECP was performed on 2 consecutive days once a month. Oral 8-methoxypsoralen was used as photosensitizer. Previous immunosuppressive treatment with either prednisolone or prednisolone/ azathioprine was continued. RESULTS: Complete remission (absence of skin or mucous membrane lesions) was achieved in the 6 patients with PV and BP after 1-4 cycles. In the patient suffering from pemphigus foliaceus, a partial remission (> 50% improvement) was observed; in all except this patient, the immunosuppressive treatment could be tapered. Long-term remission was achieved. No severe side effects were observed. The treatment was well tolerated. CONCLUSIONS: Short-time ECP is an effective and safe adjuvant treatment for patients with drug-resistant autoimmune bullous diseases. It can induce remission and allows dose tapering of the immunosuppressive drugs.     

A Case of Bullous Pemphigoid with Antibodies against Intercellular 130 KD Antigen

Pemphigus and bullous pemphigoid are two typical autoimmune bullous diseases that involve circulating autoantibodies directed against the epidermal cell surface and the epidermal basement membrane zone, respectively. The coexistence of pemphigus and bullous pemphigoid is rare. We describe a case of a 79-year-old man who had tense bullae and erythematous, erosive lesions on his trunk and four extremities. Histopathology revealed subepidermal blister formation without any evidence of intraepidermal acantholytic changes. Direct immunofluorescence study demonstrated deposition of IgG on the epidermal intercellular spaces, as well as along the basement membrane zone; C₃ was detected only on the latter. Indirect immunofluorescence study using monkey esophagus as a substrate demonstrated the presence of circulating antibodies against both junctional and intercellular antigens. In order to analyze the precise nature of this patient's antibodies, indirect immunofluorescence study using cultured human keratinocytes and immunoblot analyses were performed. Pemphigus vulgaris sera showed smooth and uniform staining on intercellular spaces. The patient's serum showed a granular and uneven staining pattern. Immunoblot analysis showed that the patient's serum reacted with the typical 230 kd (bullous pemphigoid) antigen and 130 kd antigen, which is close to the pemphigus vulgaris antigen.     

Blistering disorders: diagnosis and treatment

Blistering diseases are a heterogeneous group of disorders that can affect either skin and mucous membrane, or both, varying in presentation, clinical course, pathohistology, immunopathology and treatment. Not infrequently the diagnosis is delayed. This can result in severe, and sometimes fatal consequences. Although these diseases are rare, it is very important to make an accurate diagnosis based on a combination of clinical profile and laboratory observations. A brief review is presented of the following bullous diseases: pemphigus, paraneoplastic pemphigus, bullous pemphigoid, cicatricial pemphigoid, epidermolysis bullosa acquisita, dermatitis herpetiformis, linear IgA bullous disease, porphyria cutanea tarda, and subcorneal pustular dermatitis. Their clinical, pathohistologic and immunopathologic features and recommendations for therapy are discussed.     

Antibody deposits in Tzanck smears in pemphigus vulgaris

Forty-three patients, including 24 males and 19 females between 5 and 62 years of age, having pemphigus vulgaris (27), pemphigus foliaceus (1), bullous pemphigoid (3), chronic benign bullous dermatosis of childhood (2) and herpes zoster (10) were included in this study. Tzanck smears were prepared from the floor of the blisters in these patients by deroofing the bullae, and the slides were stored without fixation at room temperature for 1 to 10 days. Immunofluorescence staining was done with FITC-conjugated anti-human IgG. Twenty-one cases having pemphigus vulgaris and 1 case having pemphigus foliaceus showed bright green fluorescence on the membrane of acantholytic cells. No epithelial cells were seen in smears from bullous pemphigoid and chronic benign bullous dermatosis of childhood, whereas epithelial cells were seen in 10 cases of herpes zoster. These stained negative with anti-IgG. Storage of the prepared smears for 1–10 days did not seem to affect the results of immunofluorescence. Tzanck smears can be used as an easy substitute for skin/mucosal biopsy for the direct immunofluorescence test.     

Place of human amniotic membrane immunoblotting in the diagnosis of autoimmune bullous dermatoses

Background Fine analysis of antiskin autoantibodies can contribute to the differential diagnosis of autoimmune bullous dermatoses. Objectives To develop a high‐performance immunoblotting method using human amniotic membrane as the antigen source, and to compare it with current laboratory methods. Methods Sera from 113 patients were tested by immunoblotting (IB), rat and monkey oesophagus and salt‐split skin indirect immunofluorescence (IIF), and enzyme‐linked immunosorbent assay (ELISA) quantification of anti‐BP180‐NC16a and anti‐BP230, or antidesmoglein (Dsg) 1 and 3 antibodies. There were 56 cases of bullous pemphigoid (BP), 22 cases of mucous membrane pemphigoid (MMP), eight cases of epidermolysis bullosa acquisita (EBA), two cases of bullous systemic lupus erythematosus (BSLE), 17 cases of pemphigus vulgaris (PV), and four cases each of pemphigus foliaceus (PF) and paraneoplastic pemphigus (PNP). Results In BP, the three methods had similar sensitivity (84–89%) for both anti‐BP180‐NC16a and anti‐BP230 antibody detection. In MMP, autoantibodies (mainly directed against BP180 or laminin 332 subunits) were detected in 77% of patients by IB, compared with only 9% by IIF on rat and monkey oesophagus and 36% on salt‐split skin, and 14% by anti‐BP180‐NC16a and anti‐BP230 ELISA. In patients with pemphigus, ELISA had 92% sensitivity for anti‐Dsg1 and 3, but IB and rat bladder IIF were necessary to confirm PNP by revealing specific and rare patterns (antidesmoplakin I/II, antienvoplakin and antiperiplakin antibodies). IB also revealed anticollagen VII antibodies in 60% of patients with EBA and BSLE, and antibodies to BP180, BP230 and Dsg3 in a few patients who were negative using the other two techniques. Conclusion Amniotic membrane immunoblotting is an interesting diagnostic tool for bullous diseases, as the entire panel of autoantibodies can be detected with a single extract. This method improves the identification of complex and heterogeneous autoimmune processes in conjunction with IIF and ELISA, and is particularly useful for MMP characterization.     

Autoimmune subepidermal blistering diseases in Uganda: correlation of autoantibody class with age of patients

BACKGROUND: No data are available on the incidence and immunoreactivity of autoimmune subepidermal blistering skin diseases in East Africa. METHODS: All patients with frank blisters/erosions on the skin and/or mucous membranes that attended the Department of Dermatology at Mbarara University, Uganda, from May 2000 to June 2002, were investigated. The diagnosis was based on the clinical presentation and on the presence of circulating autoantibodies detected by indirect immunofluorescence microscopy on 1 m NaCl-split human skin and by Western blotting of recombinant and cell-derived forms of BP180, BP230, and type VII collagen. RESULTS: Twenty-two patients with autoimmune subepidermal blistering skin disorders were identified, including nine with bullous pemphigoid (41%), four with linear immunoglobulin A (IgA) disease (18%), three with mucous membrane pemphigoid (14%), two with linear IgG/IgA bullous dermatosis (9%), and one each with cicatricial pemphigoid and epidermolysis bullosa acquisita (5%). In addition, two patients with immunoreactivity to both the epidermal and dermal side of salt-split skin by indirect immunofluorescence microscopy, who were unreactive to type VII collagen, were provisionally diagnosed as "mixed pemphigoid" (9%). In patients with subepidermal blistering diseases, IgG reactivity correlated significantly with old age, whereas younger patients preferentially developed IgA autoantibodies (P = 0.024). CONCLUSIONS: The age of patients with autoimmune subepidermal blistering diseases appears to influence the immunoglobulin class of autoantibodies. The high frequency of IgA autoantibodies in Ugandan patients may be explained by the age distribution of the Ugandan population.     

Autoimmune bullous skin diseases. Part 1: Clinical manifestations

Autoimmune bullous skin diseases are characterized by autoantibodies against adhesion molecules of the skin. Pemphigus is a disorder with an intraepidermal loss of adhesion and is characterized by fragile blisters and erosions. Pemphigus vulgaris often shows extensive lesions of the oral mucosa, while pemphigus foliaceus is commonly restricted to cutaneous involvement with puff pastry-like scale formation. Paraneoplastic pemphigus is obligatorily associated with malignancies and often presents as hemorrhagic stomatitis with multiforme-like exanthems. IgA pemphigus typically presents with pustules and annular plaques but not with mucosal involvement. The clinical spectrum of the pemphigoids includes tense blisters, urticarial plaques, and prurigo- like eczematous lesions. Pemphigoid gestationis mostly occurs during the last trimester of pregnancy and mucous membrane pemphigoid primarily involves the oral mucosa and conjunctivae and leads to scarring. Linear IgA bullous dermatosis manifests with tense blisters in a "cluster of jewels"-like pattern in childhood and is more heterogeneous in adulthood. Classical epidermolysis bullosa acquisita shows extensive skin fragility. Dermatitis herpetiformis is associated with gluten-sensitive enteropathy and manifests clinically with severe itching and papulovesicles on the extensor surfaces of the extremities and the lumbosacral area. The intention of the review is to demonstrate the heterogeneous clinical spectrum of autoimmune bullous disorders.     

A sensitive and restricted enzyme-linked immunosorbent assay for detecting a heterogeneous antibody population in serum from people suffering from a new variant of endemic pemphigus

We recently described a new variant of endemic pemphigus foliaceus (EPF) in El Bagre, Colombia, that resembles Senear-Usher syndrome and identified autoantibodies to desmoglein 1 (Dsg1), as well as to multiple known and unknown antigens including plectins, in the serum of these patients. Here, we developed a cost-effective ELISA assay capable of detecting the heterogeneous antibody population observed in these EPF patients, and useful for serum epidemiological studies. A protein extract obtained from trypsin-digested fresh bovine skin and further purified on a concanavalin A matrix was used as antigen. This extract contains an important conformational epitope (a 45 kDa tryptic fragment of the Dsg1 ectodomain), which is recognized by antibodies in serum from patients with all varieties of pemphigus foliaceus (PF), and from half of those with pemphigus vulgaris with active clinical disease. The cut-off and threshold values were normalized using human serum obtained from both endemic and non-endemic areas for PF. The efficiency of this ELISA was tested using 600 serum samples from controls and patients diagnosed with EPF, non-endemic PF and other bullous diseases. The overall sensitivity and specificity of the assay were determined to be 95% and 72%, respectively, with reproducibilities of 98% (intraassay) and 95% (interassay). Comparing the ELISA with other tests to detect EPF autoantibodies, this ELISA was the most sensitive, followed by direct immunofluorescence (DIF), indirect immunofluorescence using anti-IgG4 monoclonal antibodies and immunoprecipitation (IP), respectively. The most specific assay was IP, followed by DIF. Immunoblotting to Dsg1 exhibited both poor sensitivity and poor specificity, although plectins were well visualized. We conclude that this ELISA is an excellent tool for field serological studies, allowing testing of multiple serum samples simultaneously and for detecting, with appropriate restriction and sensitivity, the heterogeneous antibody population seen in patients with this variant of EPF. Finally, autoantibody serum levels obtained with this ELISA correlated well with the clinical activity and extent of disease in patients with El Bagre EPF.Abbreviations BMZ Basement membrane zone - BP Bullous pemphigoid - BP180 Bullous pemphigoid 180 kDa antigen - ConA Concanavalin A - CPF Cazanaves pemphigus foliaceus - DIF Direct immunofluorescence - ELISA Enzyme-linked immunosorbent assay - EPF Endemic pemphigus foliaceus - IB Immunoblotting - IIF Indirect immunofluorescence - IP Immunoprecipitation - mAb Monoclonal antibody - PBS Phosphate-buffered saline - PBS^– Phosphate-buffered saline lacking divalent cations - PF Pemphigus foliaceus - PV Pemphigus vulgaris - SLE Systemic lupus erythematosus This paper is part of the doctoral (PhD) thesis of Ana María Abréu Vélez, MD, while at the University of Antioquia.     

Pitfalls in the diagnosis of pemphigus vulgaris (early pemphigus vulgaris with features of bullous pemphigoid)

This report draws attention to pitfalls that may be encountered in histologic diagnosis of early stages of pemphigus vulgaris. A man is described who had clinical and histologic features of bullous pemphigoid to begin with and later typical features of pemphigus vulgaris. Intercellular antibodies were demonstrable by direct immunofluorescence from the beginning.     

Human placental amnion is a novel substrate for detecting autoantibodies in autoimmune bullous diseases by immunoblotting

BACKGROUND: Identification of antigens by immunoblotting techniques, using epidermal and dermal extracts, is regarded as essential for making a definitive diagnosis in autoimmune bullous diseases (AIBDs). These procedures involve epidermal-dermal separation for subsequent protein extraction, which may result in partial loss of some antigenic polypeptides and changes in the conformational epitopes targeted by autoantibodies in AIBDs. It may therefore be necessary to use different substrates for consistent results. Objectives To evaluate the usefulness of human placental amnion extract as a substrate for immunoblotting in the diagnosis of AIBDs. METHODS: We checked the structural components of the desmosomes and basement membrane zone (BMZ) of amnion by electron microscopy. Using immunofluorescence and immunoblotting techniques, we tested the amnion immunoreactivity with antibodies to desmosomal and BMZ proteins, and with sera from 76 patients with AIBDs including pemphigus vulgaris, pemphigus foliaceus, bullous pemphigoid (BP), pemphigoid gestationis, linear IgA bullous dermatosis, epidermolysis bullosa acquisita, paraneoplastic pemphigus and mucous membrane pemphigoid. RESULTS: The desmosomes and BMZ of the amnion tissue were ultrastructurally similar to those in skin. Antigen mapping confirmed that amnion contains all the proteins that were recognized by a panel of monoclonal and polyclonal antibodies. Immunoblotting showed that the antibodies clearly detected bands corresponding to desmogleins 1 and 3, desmocollins 1 and 2, desmoplakins 1 and 2, three subunits (alpha3, beta3 and gamma2) of laminin 5, BP antigens 1 and 2, the 97-kDa LAD antigen and type VII collagen. In addition, most of the patient sera (82%) reacted exclusively with their respective antigens. CONCLUSIONS: Harvesting proteins from amnion does not require epidermal-dermal separation, and a sufficient yield of desmosomal and hemidesmosomal proteins can be obtained. Therefore, amnion may be a more reliable source of substrate than skin samples for immunoblot analysis of AIBDs.