In vitro complement activation by antinuclear antibodies in the epidermis from patients with systemic sclerosis

Abstract

Skin biopsies from 21 systemic sclerosis patients with significant serum fluorescent antinuclear antibody (FANA) titers (> 1:40) were examined by direct immunofluorescence (DIF) and by in vitro immunofluorescent complement (C) activation (C + DIF). Eight patients showed epidermal nuclear ANA deposits by DIF. In vitro complement activation was achieved in epidermal nuclei from all 8 patients. In addition, 1 patient with diffuse scleroderma revealed a dense speckled, and 2 patients with the CREST [calcinosis, Raynauds phenomenon, esophageal dysmotility, sclerodactyly, telangiectasia] syndrome a discrete speckled, epidermal nuclear staining pattern by C + DIF. The latter 2 patients showed high titers of anticentromere antibody in their sera. The C + DIF findings of these 2 patients with the CREST syndrome may reflect binding of serum anticentromere antibodies to their antigens in vivo.