2 PATIENTS WITH UNUSUAL SKIN-LESIONS AND CIRCULATING ANTIKERATINOCYTECELL-SURFACE ANTIBODIES - DETECTION OF ANTIBODIES TO THE INTRACELLULAR DOMAIN OF THE PEMPHIGUS FOLIACEUS ANTIGEN (DESMOGLEIN) BY STUDIES USING FUSION PROTEINS

We report two patients with unusual skin lesions, who had antikeratino cyte cell surface IgG autoantibodies in their sera. Immunoblot analysi s of both a human epidermal extract and a bovine desmosome preparation revealed that the sera of both patients reacted exclusively with the 160-kDa pemphigus foliaceus antigen (desmoglein). We further investiga ted the antigen molecule using bacterial fusion proteins produced by u sing bovine desmoglein cDNA, and found that both the sera reacted stro ngly and exclusively with the intracellular domain of the desmoglein. These results suggest that production of antidesmoglein autoantibodies in the present cases may be an epiphenomenon associated with damage t o the keratinocyte cell membrane.