Autoantibody formation against a 190‐kDa antigen of the desmosomal plaque in pemphigus foliaceus

Summary We report changes in the antigen recognition pattern of sera from two pemphigus foliaceus patients with a long-term follow-up. The patients' sera were analysed by immunoblotting using different antigenic sources: cultured human keratinocytes, bovine tongue epithelium and a recombinant protein corresponding to the C-terminal end of the 230-kDa bullous pemphigoid antigen. While initial serum samples reacted exclusively with the 160-kDa desmoglein 1, the later sera reacted both with desmoglein 1 and a 190-kDa antigen immunolocalized to the desmosomal plaque, previously demonstrated to be recognized by sera of some patients with paraneoplastic pemphigus. lgG subclass analysis further showed that antidesmoglein 1 antibodies were of lgGl and/or IgG4 subclasses, while anti-190-kDa antibodies were lgG3. The patients were free of malignancy.