A NOVEL VARIANT OF ACQUIRED EPIDERMOLYSIS-BULLOSA WITH AUTOANTIBODIESAGAINST THE CENTRAL TRIPLE-HELICAL DOMAIN OF TYPE-VII COLLAGEN

Epidermolysis bullosa acquisita and bullous systemic lupus erythematos us are autoimmune bullous disorders, with tissue-bound and circulating autoantibodies reactive with the noncollagenous NCI domain of type VI I collagen (C-VII). Here, we describe a novel acquired bullous dermato sis with autoantibodies against the triple-helical domain of C-VII. Th ree patients, all Japanese children, presented with widespread inflamm atory tense blisters. Histologically, subepidermal tissue separation w as noted with inflammatory infiltrate in the superficial dermis. Direc t immunofluorescence staining revealed linear IgG/C3 deposits along th e dermal-epidermal junction. Circulating IgG anti-basement membrane zo ne autoantibodies stained the dermal side of normal skin separated wit h 1 M NaCl. Direct and indirect immunoelectron microscopy using colloi dal gold labeling showed that patient sera reacted with anchoring fibr ils. The gold particles were localized both near the lamina densa and on the central banded portion of the fibrils. The sera reacted with C- VII in immunoblots. Epitope analyses with natural and recombinant frag ments of C-VII disclosed that the sera did not recognize the NCI domai n of C-VII, but the central triple-helical domain of this anchoring fi bril protein. Thus, the present probands show a hitherto unrecognized variant of epidermolysis bullosa acquisita, with autoantibodies agains t epitopes in the collagenous domain of C-VII.