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.