Epidermolysis bullosa acquisita and anti-p200 pemphigoid as major subepidermal autoimmune bullous diseases diagnosed by floor binding on indirect immunofluorescence microscopy using human salt-split skin.

BACKGROUND: Subepidermal autoimmune bullous diseases are a diverse group of diseases with overlapping clinical and immunopathological features. Indirect immunofluorescence microscopy on artificially split skin helps to classify these conditions into those with staining on the epidermal side of the split ("roof-binding") and those with staining on the dermal side ("floor-binding"). Epidermolysis bullosa acquisita is the prototype of "floor-binding" subepidermal autoimmune bullous diseases. However, not all floor-binding sera are associated with epidermolysis bullosa acquisita. AIM: The aim of this study was to evaluate the clinical and immunological profile of patients with floor-binding subepidermal autoimmune bullous disease by indirect immunofluorescence microscopy and to identify the target antigens in them. METHODS: Ten patients who showed a floor-binding pattern were studied with regard to their clinical and immunopathological characteristics. Target antigens were identified by modified indirect immunofluorescence microscopy using recessive dystrophic epidermolysis bullosa skin, enzyme linked immunosorbent assay, and immunoblotting. RESULTS: Diagnosis of epidermolysis bullosa acquisita was confirmed in six patients. Three patients with an inflammatory subepidermal autoimmune bullous disease mimicking bullous pemphigoid reacted with a 200 kDa protein on immunoblotting with dermal extract, as is characteristic of anti-p200 pemphigoid. One serum showed both roof and floor binding, and reacted with the BP180 antigen. LIMITATION: We could not perform serration pattern analysis in our patients. CONCLUSION: In this study, we report three cases of anti-p200 pemphigoid from India. These cases, though indistinguishable clinically from bullous pemphigoid, revealed a floor-binding pattern on indirect immunofluorescence using salt-split skin.

Accuracy of indirect immunofluorescence on sodium chloride-split skin in the differential diagnosis of bullous pemphigoid and epidermolysis bullosa acquisita.

BACKGROUND: Previous reports have shown that indirect immunofluorescence (IIF) performed on sodium chloride-split skin (SSS) is helpful to differentiate epidermolysis bullosa acquisita (EBA) from bullous pemphigoid (BP). Antibodies of BP may bind to the epidermal side of SSS, while antibodies of EBA bind to the dermal side. AIMS: To determine the accuracy of IIF-SSS in the differential diagnosis of EBA and BP utilizing immunoblotting (IB) analysis. METHODS: Sera from 78 patients, diagnosed with BP by clinical features, histopathology, and direct immunofluorescence (DIF), were assayed using IIF-SSS and IB. RESULTS: Of the 43 serum samples with an epidermal reaction to IIF-SSS assay, 42 were recognized with BP antigens (180 kDa or 230 kDa). Of the 11 serum samples with a dermal reaction pattern, 7 were recognized with the 290 kDa antigen of EBA and 3 with sera bound BP antigens. Seven serum samples with epidermal and dermal combined staining, of which 5 of them reacted with BP antigens, 1 reacted with both BP and EBA antigens. One serum sample from each group showed a negative result by IB. Approximately 9.0% (7/78) of patients diagnosed with BP using regular methods were actually EBA. CONCLUSIONS: Epidermal reaction using the IIF-SSS assay highly correlated with the diagnosis of BP. However, dermal reactions correlated poorly with EBA, with some serum samples from BP patients binding to dermal-side antigens. In both epidermal and dermal stained sera using IIF-SSS, there was a possibility of BP and EBA. Differential diagnosis should be confirmed using IB, especially in cases of dermal and double staining patterns assayed using IIF-SSS.

[Epidermolysis bullosa acquisita of childhood]. / Epidermolyse bulleuse acquise de l'enfant.

BACKGROUND: Epidermolysis bullosa acquisita (EBA) is a subepidermal autoimmune blistering disease characterized immunologically by autoantibodies to type VII collagen. Its occurrence in childhood is rare. Thirty-five cases have been described to date in the literature. PATIENTS AND METHODS: We report the case of an 8-year-old girl presenting blistering lesions on the cheeks, extremities and limb extension areas. The diagnosis of EBA was confirmed by histology, direct immunofluorescence of a perilesional skin biopsy specimen, indirect immunofluorescence on salt-split skin substrate and direct electron microscopy. The patient was controlled clinically under treatment with dapsone alone. DISCUSSION: This 36th childhood case of EBA presented typical clinical features, a similar prognosis and comparable treatment response to other paediatric cases. Clinical presentation is inflammatory and affects the face. As in our case, in childhood, prognosis is often better than in adults without the need for immunosuppressive agents.