A CASE OF PEMPHIGUS-VULGARIS SHOWING REACTIVITY WITH PEMPHIGUS ANTIGENS (DSG1 AND DSG3) AND DESMOCOLLINS

Both pemphigus vulgaris antigen (PVA; Dsg3) and pemphigus foliaceus an tigen (PFA; Dsg1) are members of the desmoglein subfamily of the cadhe rin supergene family. Another desmosomal cadherin, desmocollin, is occ asionally recognized by certain pemphigus sera. We present a 38-year-o ld Japanese male who showed clinically and histopathologically typical features of pemphigus vulgaris, whose sera reacted with all PVA, PFA, and desmocollins using immunoblotting of both human epidermis and bov ine snout epidermis. Studies using domain-specific fusion proteins of PFA and PVA suggested that this patient's serum reacted with the intra cellular domain of PFA and the extracellular domain of PVA, the latter of which seems to be responsible for initiating the skin lesion. The patient's serum showed reactivity with human desmocollin and was shown to react with bovine Dsc2 fusion protein, further suggesting the sign ificance of anti-desmocollin autoantibodies in pemphigus. These result s indicate that certain pemphigus cases may produce antibodies against multiple antigen molecules, although the complex mechanism of the pro duction of autoantibodies remains to be elucidated.