Laminin ß4 is a constituent of the cutaneous basement membrane zone and additional autoantigen of anti-p200 pemphigoid.

BACKGROUND: Anti-p200 pemphigoid is a subepidermal autoimmune blistering disease (AIBD) characterized by autoantibodies against a 200 kDa protein. Laminin γ1 has been described as target antigen in 70% to 90% of patients. No diagnostic assay is widely available for anti-p200 pemphigoid, which might be due to the unclear pathogenic relevance of anti-laminin γ1 autoantibodies. OBJECTIVE: To identify a target antigen with higher clinical and diagnostic relevance. METHODS: Immunoprecipitation, mass spectrometry, and immunoblotting were employed for analysis of skin extracts and sera of patients with anti-p200 pemphigoid (n = 60), other AIBD (n = 33), and healthy blood donors (n = 29). To localize the new antigen in skin, cultured keratinocytes and fibroblasts, quantitative real-time polymerase chain reaction and immunofluorescence microscopy were performed. RESULTS: Laminin ß4 was identified as target antigen of anti-p200 pemphigoid in all analyzed patients. It was located at the level of the basement membrane zone of the skin with predominant expression in keratinocytes. LIMITATIONS: A higher number of sera needs to be tested to verify that laminin ß4 is the diagnostically relevant antigen of anti-p200 pemphigoid. CONCLUSION: The identification of laminin ß4 as an additional target antigen in anti-p200 pemphigoid will allow its differentiation from other AIBD and as such, improve the management of these rare disorders.

Utility of the pattern-based approach using BIOCHIP-indirect immunofluorescence in the evaluation of subepidermal bullous disorders.

BACKGROUND: Subepidermal bullous disorders (SEBD) are a heterogeneous group of vesiculobullous diseases because of antibody-mediated destruction of proteins of the dermo-epidermal junction. Direct immunofluorescence (DIF) is the gold standard for diagnosis. BIOCHIP-indirect immunofluorescence (IIF) is a novel serological test that combines multiple target antigens in a single field. The present study aimed to evaluate the utility of the pattern-based approach in BIOCHIP-IIF for the diagnosis of SEBD. METHODS: Seventy cases of BIOCHIP-IIF that showed clinical, histopathological, and/or DIF features favoring SEBD were included in the study. The interpretation in the BIOCHIP was categorized into one of the following patterns. Pattern I: basement membrane zone (BMZ) staining in monkey esophagus (ME), primate salt-split skin (SSS)-roof staining, BP180+ and/or BP230+; Pattern II: roof staining in SSS, BP180- and BP230- with or without BMZ staining in ME; Pattern III: floor staining in SSS, BP180- and BP230-; and pattern IV: negative in SSS and other substrates. The findings were correlated with histopathology and/or DIF. RESULTS: Fifty (71.5%) cases showed pattern I or the typical bullous pemphigoid (BP) pattern. Eight (11.4%) cases showed pattern II. Patterns III and IV were observed in seven (10%) and five (7.1%) cases, respectively. BP was the most common diagnosis in patterns I and II, while anti-p200 pemphigoid was most common in pattern III, as confirmed by immunoblotting. The sensitivity of pattern I in the diagnosis of BP was 96%. CONCLUSION: BIOCHIP-IIF showed a good correlation with DIF and histopathology in the diagnosis of SEBD. This can be used as a first-line investigation in case of bullous disorders.

Subepithelial autoimmune bullous dermatoses disease activity assessment and therapy.

Subepidermal (subepithelial) autoimmune blistering dermatoses are a group of rare skin disorders characterized by the disruption of the dermal-epidermal junction through the action of autoantibodies. The fourth article in this continuing medical education series presents the current validated disease activity scoring systems, serologic parameters, treatments, and clinical trials for bullous pemphigoid, mucous membrane pemphigoid, epidermolysis bullosa acquisita, bullous systemic lupus erythematosus, anti-p200 pemphigoid, linear IgA bullous dermatosis, and dermatitis herpetiformis.

Usefulness of a Simple Immunohistochemical Staining Technique to Differentiate Anti-p200 Pemphigoid From Other Autoimmune Blistering Diseases: A Report of 2 Cases. / Descripción de 2 casos de penfigoide anti-p200. Utilidad de una técnica inmunohistoquímica sencilla en el diagnóstico diferencial con otras enfermedades ampollosas autoinmunes.

Anti-p200 pemphigoid is a rare autoimmune subepidermal blistering disease characterized by the presence of circulating immunoglobulin G antibodies directed against laminin gamma-1, a 200-kDa protein located in the lamina lucida of the basement membrane. We review the clinical, histopathological and immunological characteristics of the first 2 cases described in Spain. Anti-p200 pemphigoid shares histopathological and immunopathological findings with epidermolysis bullosa acquisita, the main entity in the differential diagnosis. However, its management follows the same guidelines as those used for bullous pemphigoid. The diagnosis is confirmed by immunoblotting, which is a complex technique available in few centers. We propose the immunohistochemical detection of collagen type IV on the floor of the blister, combined with standard immunofluorescence techniques, as a simple, accessible alternative to differentiate anti-p200 pemphigoid from epidermolysis bullosa acquisita.

Anti-p200 pemphigoid.

Anti-p200 pemphigoid is a rare subepidermal blistering skin disease. Patients' autoantibodies label the dermal side of 1 mol/L NaCl-split human skin by indirect immunofluorescence microscopy and recognize a 200-kd protein by immunoblotting of human dermal extract. Clinically, anti-p200 pemphigoid is characterized by tense blisters and vesicles, erosions, and urticarial plaques, closely resembling bullous pemphigoid and the inflammatory variant of epidermolysis bullosa acquisita. Recently, 90% of anti-p200 pemphigoid sera were shown to recognize laminin γ1. The C-terminus of laminin γ1 was identified as an immunodominant region and in its recombinant form was used by immunoblotting and enzyme-linked immunosorbent assay for the serologic diagnosis of this disease. Subsequent ex vivo and in vivo studies were, however, unable to show pathogenic activity of antilaminin γ1 antibodies. Both patients' sera and sera depleted from antilaminin γ1 antibodies induced subepidermal splitting in an ex vivo model of autoantibody-mediated leukocyte-dependent neutrophil activation. Antilaminin γ1 antibodies appear to be useful biomarkers that will further facilitate the diagnosis of anti-p200 pemphigoid. The true identity of the pathogenetically relevant autoantigen of this disease, which may either be a yet unknown isoform of laminin γ1 or even another 200-kd protein of the dermoepidermal junction, still needs to be elucidated.

Clinical and immunoserological characteristics of anti-p200 pemphigoid: Comparisons of patients with epitope spreading and non-epitope spreading.

BACKGROUND: Anti-p200 pemphigoid is a rare autoimmune subepidermal blistering disease. Although the phenomenon of epitope spreading has been reported to be common in anti-p200 pemphigoid, the association between its clinical and immunoserological features has yet to be elucidated. OBJECTIVES: Our aim was to compare the clinical and immunoserological characteristics of anti-p200 pemphigoid patients with and without epitope spreading. METHODS: We performed a retrospective cohort study encompassing 30 patients with anti-p200 pemphigoid between January 2015 and December 2022. The clinical and immunoserological characteristics of anti-p200 pemphigoid were analyzed using combined immunoserological assays. RESULTS: Epitope spreading was observed in 11 of 30 patients (36.7%) with anti-p200 pemphigoid. Compared with patients in the non-epitope spreading group, patients in the epitope spreading group showed more heterogeneous clinical presentations (P = 0.018), a higher proportion of mucosal involvement (P = 0.003), higher Bullous Pemphigoid Disease Area Index (BPDAI) scores for skin erosions/blisters (P = 0.018), mucosal erosions/blisters (P = 0.001), activity (P = 0.017) and total scores (P = 0.022), and required a higher initial dose of prednisone for disease control (P = 0.040). CONCLUSIONS: This study supported the idea that anti-p200 pemphigoid was prone to epitope spreading. Anti-p200 pemphigoid patients with epitope spreading are more likely to present heterogeneous clinical phenotypes, frequent mucosal involvement, and a more severe and recalcitrant disease course.

[Anti-p200 pemphigoid: Remission under mycophenolate mofetil (Cellcept®)]. / Pemphigoïde anti-p200: rémission sous mycophénolate mofétil (Cellcept®).

BACKGROUND: Anti-p200 pemphigoid is a recently described autoimmune subepidermal bullous dermatosis characterized by its target antigen and the associated anatomoclinical picture. The treatment is not as yet well defined. PATIENT AND METHODS: A 73-year-old man consulted for a pruritic bullous eruption with buccal involvement. Direct immunofluorescence revealed linear deposits of IgG and C3 at the dermal-epidermal junction. Elisa screening for circulating anti-BP180 and anti-BP230 antibodies was negative. A diagnosis of bullous pemphigoid was suspected. After an unfavourable clinical outcome under clobetasol and then prednisolone and methotrexate, other immunological tests were performed. Indirect immunofluorescence on NaCl-cleaved skin revealed a deposit of IgG4 antibodies on the dermal side. Immunoblotting showed antibodies directed against a 200-kDa antigen on a dermal extract. A diagnosis of anti-p200 pemphigoid was made. The patient was treated with dapsone combined with prednisolone. Seventy-two hours later, treatment was stopped due to hepatic cytolysis related to immunoallergic hepatitis. Treatment with mycophenolate mofetil was then initiated and resulted in complete remission, which persisted at seven months. DISCUSSION: The diagnosis of anti-p200 pemphigoid was made on the basis of a set of clinical and immunological factors. Anti-p200 pemphigoid differs from standard bullous pemphigoid in terms of more frequent cephalic, acral and mucous membrane involvement, as well as a greater degree of miliary scarring. There was no eosinophilia. Elisa screening for anti-BP180 and anti-BP230 antibodies was negative. Immunoblotting showed antibodies directed against a 200kDa protein on dermal extract. The treatment is not well defined, even if dapsone appears to be the most effective therapy. To our knowledge, our patient is the first to be successfully treated with mycophenolate mofetil. CONCLUSION: Treatment of anti-p200 pemphigoid is difficult. In our case, treatment by mycophenolate mofetil was effective and could offer an alternative to dapsone.

[Pemphigoid diseases in older adults]. / Pemphigoiderkrankungen bei älteren Menschen.

Pemphigoid diseases are a group of bullous autoimmune diseases characterized by autoantibodies against structural proteins of the dermal-epidermal junction. With a steadily growing aging population, pemphigoid diseases are emerging as a significant medical challenge, because they occur primarily in older individuals. The by far most common disease is bullous pemphigoid, which is clinically characterized by tense blisters, erosions, erythema or urticarial plaques, while severe pruritus is the leading subjective symptom. Mucous membrane pemphigoid predominantly affects surface-close mucous membranes with painful erosions and blisters as well as frequently scarring usually in the mouth, nose, and eyes. Anti-p200 pemphigoid clinically resembles bullous pemphigoid but is much less common. Diagnosis of these diseases involves the combination of clinical evaluation, lesional histopathology, direct immunofluorescence microscopy of a perilesional biopsy and serology. Topical and systemic corticosteroids are the mainstay of pemphigoid diseases treatment. Depending on the severity of the disease, various potentially corticosteroid-sparing therapies, such as dapsone, doxycycline, methotrexate, azathioprine and mycophenolate may be used. In severe courses, treatment with rituximab, cyclophosphamide, intravenous immunoglobulins or immunoadsorption are second- or third-line treatment options. Patients are best managed in centers experience with the management of pemphigoid diseases. Updated national and international guidelines for the diagnosis and treatment of bullous pemphigoid and mucous membrane pemphigoid have recently been published.

Potential contribution of anti-p200 autoantibodies to mucosal lesions in anti-p200 pemphigoid.

Anti-p200 pemphigoid is a relatively rare subepidermal autoimmune bullous disease (AIBD), which was firstly reported by Detlef Zillikens, Takashi Hashimoto and others in 1996. Skin lesions are considered as the major clinical features of this disease, with occasional involvement of mucosal lesions. The mechanism of mucosal lesions involved in anti-p200 pemphigoid is still unclear. In the present study, we aimed to analyze published data on cases and case series of anti-p200 pemphigoid with mucosal lesions and explored the potential contribution of anti-p200 autoantibodies to mucosal lesions. A total of 32 papers that comprised 52 anti-p200 pemphigoid patients with various mucosal lesions were included in this review. Oral lesions were involved in 75.0% patients, followed by genital lesions (26.9%) and ocular lesions (11.54%). Only one patient had psoriasis, 26.9% patients had multiple mucosal lesions, and 30.8% cases had comorbidity of other AIBDs, particularly anti-laminin (LM) 332-type mucous membrane pemphigoid (MMP). In comparison with anti-LM332-type MMP, anti-BP180-type MMP and epidermolysis bullosa acquisita, higher frequency of genital lesions was identified as a unique character of anti-p200 pemphigoid with mucosal lesions. These results indicated that anti-p200 autoantibodies might contribute to mucosal lesions in a pattern different from other MMP-related autoantibodies, although its pathogenetic mechanisms are still unclear.

Usefulness of immunofluorescence overlay antigen mapping in the identification of autoantigen in anti-p200 pemphigoid.

Anti-p200 pemphigoid is a rare subepidermal blistering disease showing immunoglobulin G (IgG) autoantibodies reactive with a 200-kDa protein. In most patients, serum IgG antibodies react with laminin γ1. The diagnosis of anti-p200 pemphigoid is occasionally difficult, mainly due to the lack of standardized tests. We performed fluorescence overlay antigen mapping by laser scanning confocal microscopy (FOAM-LSCM) to identify autoantigens in an anti-p200 pemphigoid patient and assessed its usefulness for the diagnosis. A 71-year-old man presented with blisters and erosions on the bilateral forearms. No mucosal lesions were observed. Laboratory examinations revealed mild leukocytosis and antinuclear antibody negativity. A histopathological examination showed subepidermal blisters with neutrophil infiltration. Direct immunofluorescence showed linear IgG staining along the basement membrane zone. Indirect immunofluorescence using 1 M NaCl-split skin sections revealed IgG reactivity on the dermal side. Immunoblotting detected circulating IgG autoantibodies that reacted with a 200-kDa protein. Accordingly, anti-p200 pemphigoid was diagnosed. FOAM-LSCM revealed that the patient's IgG signals were co-localized with laminin γ1 but were observed above type VII collagens. A direct immunofluorescent analysis for IgG deposition patterns showed an n-serrated pattern. Thus, FOAM-LSCM may be useful for diagnosing anti-p200 pemphigoid.

[Rare variants of pemphigoid diseases]. / Seltene Varianten der Pemphigoiderkrankungen.

Pemphigoid diseases comprise a heterogeneous group of subepidermal autoimmune blistering dermatoses characterized by autoantibodies against structural proteins of the dermal-epidermal junction. Recent decades have witnessed a significant surge in the incidence of these diseases, which, in addition to general aging of the population, can be attributed to the availability of precise diagnostic methods and improved knowledge of the clinical and immunopathological spectrum. While bullous pemphigoid, mucous membrane pemphigoid, and linear IgA disease account for most pemphigoid disorders, less frequent, presumably underdiagnosed variants are increasingly becoming relevant for clinicians. These include epidermolysis bullosa acquisita, anti-p200 pemphigoid, pemphigoid gestationis, lichen planus pemphigoides, and recently defined entities such as IgM pemphigoid and Orf-induced pemphigoid. Accurate characterization and differentiation of these subtypes are not only of diagnostic relevance but may also be associated with therapeutic and prognostic implications for affected individuals. Due to the rarity of these diseases, no controlled prospective clinical trials currently exist, making their diagnosis and therapy challenging.

Coexistence of Anti-p200 Pemphigoid and Psoriasis: A Systematic Review.

Background: A close association between psoriasis and anti-p200 pemphigoid has been demonstrated by numerous studies. However, the clinical characteristics of patients suffering from these two entities have not yet been well-elucidated. Objective: This study aimed to review the case reports and case series, summarizing clinical features and therapeutic strategies in patients suffering from anti-p200 pemphigoid and psoriasis. Methods: A systematic review was conducted by searching PubMed, EMBASE, and Web of Science databases for studies published in English involving patients with psoriasis and anti-p200 pemphigoid on 6 September 2021. All case reports and case series reporting patients diagnosed with anti-p200 pemphigoid and psoriasis were included in this systematic review. Results: A total of 21 eligible studies comprising 26 anti-p200 pemphigoid patients with preceding psoriasis were included in the qualitative synthesis. The average age at blisters eruption was 62.5 years, and the mean duration between the two entities was 15.6 years. Twenty-four percent of patients developed bullous lesions during UV therapy. Clinical manifestation of bullae and/or vesicles was recorded in all patients, and the trunk (94.7%) was most frequently involved, with only 15.8% reporting mucosal involvement. Epitope spreading was detected by immunoblotting in 33.3% of patients. All the patients reached completed remission during the course of disease, with 36.8% experiencing at least one relapse. Monotherapy of prednisolone was the leading therapeutic approach (n=6, 31.6%) required for disease control, but 5 (83.3%) of them suffered from blister recurrence after tapering or ceasing corticosteroid. Conclusion: Most of the clinical aspects of patients with anti-p200 pemphigoid and psoriasis were similar to what was demonstrated in previous articles on anti-p200 pemphigoid. Nevertheless, compared with other anti-p200 pemphigoid cases without psoriasis, a clinical manifestation pattern with more frequent involvement of the trunk and less mucosal involvement was illustrated in those with psoriasis. Generally, monotherapy is sufficient for a complete remission for such patients. However, one or more relapses have been recorded in a considerable portion of patients, especially those prescribed with prednisolone. It reminded us to be more cautious during a tapering of medication.

When Bullous Pemphigoid Is Not Bullous Pemphigoid: The Importance of Going Beyond Direct Immunofluorescence.

Bullous pemphigoid (BP) is the most common autoimmune bullous disease, but rarer forms of pemphigoid may appear identical to BP on routine histopathology and direct immunofluorescence (DIF). Here, we present the case of a 60-year-old man, who was initially thought to have BP, with supportive findings on routine histopathology and DIF. However, prominent oral involvement and cutaneous lesions refractory to conventional treatment suggested an alternate diagnosis. Further workup was performed, including indirect immunofluorescence (IIF) on salt-split skin, which showed binding of antibodies to the dermal floor rather than to the blister roof, and enzyme-linked immunosorbent assay for pemphigus and pemphigoid antibodies. With these additional tests, we concluded that the patient does not have BP but rather anti-p200 pemphigoid, anti-p105 pemphigoid, or a yet undiscovered form of pemphigoid. We reached a presumptive diagnosis of anti-p200 pemphigoid, as it is the most common pemphigoid with serum antibodies to the dermal floor of human salt-split skin by IIF. This case demonstrates that suspicion for other autoimmune bullous diseases in cases of treatment-refractory and clinically aberrant BP is essential. A limited workup may lead to a missed diagnosis and ultimately less efficient disease management.

Anti-P 200 pemphigoid - The most common floor binding subepidermal autoimmune bullous disease in a tertiary care center in south India.

BACKGROUND: The pemphigoid group of diseases may present clinically and immunologically in a very similar fashion. Indirect immunofluorescence microscopy with readily available salt-split human skin in a BIOCHIP™ helps to classify these conditions as those with either with roof binding or floor binding of immunoreactants. Epidermolysis bullosa acquisita, anti-laminin 332 pemphigoid and anti-p200 pemphigoid show floor binding, while in the most frequent type of pemphigoid disease, bullous pemphigoid, epidermal side staining pattern is seen on salt-split skin Aims: The aim of the study was to detect the target antigens in sub-epidermal bullous diseases. METHODS: Forty patients with bullous pemphigoid diagnosed by lesional histopathology and direct immunofluorescence microscopy were re-evaluated by a BIOCHIP™ mosaic containing both tissue substrates and recombinant target antigens. Sera with floor pattern staining on salt-split skin were further evaluated by immunoblotting with dermal extract. RESULTS: Five patients with floor staining had anti-p200 pemphigoid. LIMITATIONS: We could not perform serration pattern analysis of direct immunofluorescence in our patients. CONCLUSION: Histopathology and direct immunofluorescence microscopy cannot differentiate between various entities of pemphigoid diseases. A multivariant approach using a BIOCHIP™ mosaic including salt-split skin followed by immunoblotting with dermal extract helps to identify the target antigen.

Anti-p200 Pemphigoid: A Systematic Review.

The many clinical aspects of anti-p200 pemphigoid are not well-characterized. We aimed to analyze and correlate known existing data on the epidemiological, clinical, histological, and immunological features of anti-p200 pemphigoid. We performed a review using Medline, Embase, and Web of Science databases (1900-2018). Case reports and series of patients were included. A total of 68 eligible studies that comprised 113 anti-p200 pemphigoid patients were included in the qualitative analysis, where there was a mean age of onset of 65.5 years. All patients presented with bullae/vesicles, and 54.3% had urticarial plaques. A similarity to bullous pemphigoid was reported in 66.1% of cases, but palmoplantar (51.4%), cephalic (40.3%), and mucosal (38.5%) involvement, besides frequent development of scars/milia (15.7%), were reported. Autoantibodies against recombinant laminin γ1 were detected in the sera of 73.1% of patients. Psoriasis was present in 28.3% of anti-p200 pemphigoid patients, particularly among Japanese patients (56.4%). The incidence of pustular psoriasis in this subgroup, was significantly greater than in the normal population. In conclusion, the diagnosis of anti-p200 pemphigoid may be suspected when a subepidermal autoimmune blistering disease develops in a younger age group, along with significant acral and cephalic distribution and mucosal involvement.

Autoimmune Subepidermal Bullous Diseases of the Skin and Mucosae: Clinical Features, Diagnosis, and Management.

Autoimmune subepidermal blistering diseases of the skin and mucosae constitute a large group of sometimes devastating diseases, encompassing bullous pemphigoid, gestational pemphigoid, mucous membrane pemphigoid, epidermolysis bullosa acquisita, and anti-p200 pemphigoid. Their clinical presentation is polymorphic. These autoimmune blistering diseases are associated with autoantibodies that target distinct components of the basement membrane zone of stratified epithelia. These autoantigens represent structural proteins important for maintenance of dermo-epidermal integrity. Bullous pemphigoid (BP) is the most common subepidermal autoimmune blistering disease of the skin and mucosae. Although the disease typically presents with a generalized blistering eruption associated with itch, atypical variants with either localized bullous lesions or "non-bullous" presentations are observed in approximately 20% of patients. A peculiar form of BP typically associated with pregnancy is pemphigoid gestationis. In anti-p200 pemphigoid, patients present with tense blisters on erythematosus or normal skin resembling BP, with a predilection for acral surfaces. These patients have antibodies targeting the 200-kDa basement membrane protein. Epidermolysis bullosa is a rare autoimmune blistering disease associated with autoantibodies against type VII collagen that can have several phenotypes including a classical form mimicking dystrophic epidermolysis bullosa, an inflammatory presentation mimicking BP, or mucous membrane pemphigoid-like lesions. Mucous membrane pemphigoid (MMP) is the term agreed upon by international consensus for an autoimmune blistering disorder, which affects one or more mucous membrane and may involve the skin. The condition involves a number of different autoantigens in the basement membrane zone. It may result in severe complications from scarring, such as blindness and strictures. Diagnosis of these diseases relies on direct immunofluorescence microscopy studies and immunoserological assays. Management of affected patients is often challenging. We will here review the clinical and immunopathological features as well as the pathophysiology of this group of organ-specific autoimmune diseases. Finally, we will discuss the diagnostic approach and the principles of management in clinical practice.