CLINICAL AND LABORATORY INVESTIGATIONS BJD British Journal of Dermatology Diagnosis and disease severity assessment of epidermolysis bullosa acquisita by ELISA for anti-type VII collagen autoantibodies: an Italian multicentre study A.V. Marzano, 1 E. Cozzani, 2 D. Fanoni, 1 O. De Pita `, 3 C. Vassallo, 4 E. Berti, 1 A. Parodi, 2 C. Crosti 1 and M. Cugno 5 1 Unita ` di Dermatologia, Dipartimento di Fisiopatologia e dei Trapianti, Universita ` degli Studi di Milano, Fondazione IRCCS Ca’ Granda – Ospedale Maggiore Policlinico, Via Pace 9, 20122, Milano, Italy 2 Section of Dermatology, University of Genoa Medical School, Viale Benedetto XV 7, 16132, Genoa, Italy 3 Laboratory of Immunology and Allergology, Istituto Dermopatico dell’Immacolata, IDI-IRCCS, Via dei Monti di Creda 104, Roma, Italy 4 Institute of Dermatology, University of Pavia and Foundation IRCCS Policlinico S. Matteo, Vialle Camillo Golgi 19, 27100, Pavia, Italy 5 Unita ` di Medicina Interna, Dipartimento di Fisiopatologia e dei Trapianti, Universita ` degli Studi di Milano, Fondazione IRCCS Ca’ Granda – Ospedale Maggiore Policlinico, Via Pace 9, 20122, Milano, Italy Correspondence Angelo V. Marzano. E-mail: angelovalerio.marzano@policlinico.mi.it Accepted for publication 12 August 2012 Funding sources None. Conflicts of interest None. DOI 10.1111/bjd.12011 Summary Background Epidermolysis bullosa acquisita (EBA) is a rare autoimmune mucocuta- neous bullous disease caused by autoantibodies against type VII collagen, a com- ponent of anchoring fibrils that stabilizes dermoepidermal adherence. Type VII collagen is composed of a collagenous domain linked by the noncollagenous (NC)1 and NC2 domains. Objectives To assess the repeatability, sensitivity and specificity of a recently devel- oped enzyme-linked immunosorbent assay (ELISA) for detection of anti-type VII collagen autoantibodies, and to ascertain whether they may be a marker of disease activity in EBA. Methods Using this ELISA, which was able to recognize autoantibodies against the NC1 and NC2 epitopes of type VII collagen, we tested 14 EBA sera, 30 healthy control sera and 113 disease control sera. Results In the EBA sera group, 12 out of the 14 samples were positive in ELISA, with autoantibody titres varying from 7Æ2 to 127Æ9 U mL )1 (cutoff value < 6), the sensitivity of the method being 86%. Among the controls, only two bullous pemphigoid sera tested positive, the specificity being 98Æ6%. A good correlation was found between EBA disease severity, expressed as autoimmune bullous skin disorder intensity score, and the serum levels of anti-collagen VII autoantibodies, measured by ELISA (n = 14; r =0Æ965; P =0Æ0001). The intra- and interassay coefficients of variation of the ELISA method ranged from 6Æ3% to 18Æ3%. Conclusions This NC1 + NC2 ELISA can be a practical assay for the diagnosis of EBA. The correlation between autoantibody titres and disease severity suggests its usefulness as a marker of disease activity in EBA However, this should be confirmed by studies on larger series of patients. Epidermolysis bullosa acquisita (EBA) is a rare subepidermal autoimmune blistering disease of the skin and mucous mem- branes caused by autoantibodies directed against type VII col- lagen, which is a structural component of the anchoring fibrils located in the upper dermis just below the basement mem- brane zone (BMZ). 1,2 The autoantibody-mediated pathogenesis of EBA is regulated by autoreactive T cells, which provide help to collagen VII-specific B cells for the production of patho- genic autoantibodies. 3 Clinically, the classic form of EBA is a noninflammatory mechanobullous disease mainly involving trauma-prone areas of the skin, such as the hands, elbows, knees and feet, and in some cases the oral mucosa. 4 In addition to this clinical pheno- type, a variety of inflammatory clinical presentations of EBA have been identified, including bullous pemphigoid (BP)-like, mucous membrane pemphigoid (MMP)-like, Brunsting– Perry cicatricial pemphigoid (CP)-like and linear immuno- globulin A (IgA) bullous dermatitis-like phenotypes. 4 The Ó 2012 The Authors 80 BJD Ó 2012 British Association of Dermatologists 2013 168, pp80–84