Clinical features and diagnosis of epidermolysis bullosa acquisita

Abstract

Introduction: Epidermolysis bullosa acquisita (EBA) is a rare autoimmune blistering disease of skin and mucous membranes. EBA is caused by autoantibodies against type VII collagen, which is a major component of anchoring fibrils, attaching epidermis to dermis. Binding of autoantibodies to type VII collagen leads to skin fragility and, finally, blister formation. The clinical picture of EBA is polymorphic, with several distinct phenotypes being described. Despite recent progress in understanding the pathophysiology of EBA, its diagnosis is still challenging. Areas covered: This review provides an update on the clinical manifestations and diagnostic methods of EBA. We searched PubMed using the terms 'epidermolysis bullosa acquisita' covering articles in English between 1 January 2005 and 31 May 2016. Relevant older publications were retrieved form cited literature. Expert commentary: While the clinical picture is highly variable, diagnosis relies on direct immunofluorescence (IF) microscopy of a perilesional skin biopsy. Linear deposits of IgG, IgA and/or C3 along the dermal-epidermal junction with an u-serrated pattern are diagnostic for EBA alike the detection of serum autoantibodies against type VII collagen. Several test systems for the serological diagnosis of EBA have recently become widely available. In some patients, sophisticated diagnostic approaches only available in specialized centers are required. ARTICLE HISTORY

International Bullous Diseases Group: consensus on diagnostic criteria for epidermolysis bullosa acquisita

“…IB is a serological technique performed on extracts of tissues or cells or recombinant Col7 proteins (Fig. ) . IB is effective for diagnosing EBA by detecting autoAbs in patient sera that label the Col7 α‐chain.…”

“…The IgG autoantibodies (autoAbs) accounting for these DEJ immune deposits were found to be autoAbs directed against a 290‐kDa protein called type VII collagen (Col7), the major component of anchoring fibrils (AFs) in the DEJ . Since these initial observations, the diagnostic testing for EBA has undergone significant refinement …”

Accessible diagnostic methods to differentiate between epidermolysis bullosa acquisita and other subepidermal autoimmune bullous diseases

“…Alternative immunological tests available in specialized laboratories include immunoblotting, with the dermal extract containing the full-length 290 kDa type VII collagen protein and the recombinant NC1 domain. [3] In a recent multicenter retrospective serological study on 95 sera from EBA patients, Schmidt et al . concluded that type VII collagen combined NC1/NC2 domains ELISA is superior to ELISA based on type VII collagen NC1 domain only, immunoblotting, and IIF on salt-split skin, with a sensitivity of 97.9%.…”

“…Although several tests are available for this purpose, most of which are not available in routine pathology laboratories. [3]…”

Systemischer Lupus erythematodes

“…Auch wir können hier nicht eindeutig beweisen, dass Kollagen Typ VII das Autoantigen darstellt, allerdings ist das "u-serrated-Muster" der direkten IF ein sehr starker Hinweis darauf. Für manche Autoren gilt diese diagnostische Methode als Goldstandard der Epidermolysis bullosa acquisita/ des bullösen SLE [30][31][32][33] Autoimmundiagnostik: ANA positiv (1:2560), gesprenkeltes Fluoreszenzmuster, SS-A/Ro-Antikörper >240 U/ml (<10 U/ml), SS-B/La-Antikörper>320 U/ ml (<10 U/ml), Komplementfaktoren im Normbereich.…”