Detection of IgA autoantibodies to desmogleins by an enzyme-linked immunosorbent assay - The presence of new minor subtypes of IgA pemphigus

Objective: To examine the frequency of antidesmoglein 1 (Dsg1) and antidesm oglein 3 (Dsg3) IgA autoantibodies in IgA pemphigus. Design: We developed an enzyme-linked immunosorbent assay against recombina nt Dsg1 and Dsg3 to detect IgA autoantibodies. Patients: Twenty-two patients with IgA pemphigus were studied. Among them, 10 patients had subcorneal pustular dermatosis type, 9 patients had intraep idermal neutrophilic IgA dermatosis type, and 3 patients had pemphigus foli aceus-like clinical features. Results: Of the 22 cases of IgA pemphigus, 3 cases were positive for anti-D sg1 IgA antibodies and only 1 case was positive for anti-Dsg3 IgA antibodie s. In those 4 cases, there were no IgA autoantibodies against other compone nts of the keratinocyte cell surfaces because preincubation with the respec tive recombinant desmogleins removed the immunoreactivity on immunofluoresc ence. All 10 patients with subcorneal pustular dermatosis type IgA pemphigu s were positive against desmocollin 1 expressed on COS-7 cells. No target a ntigen was detected in the other 8 cases. Conclusions: Desmogleins were recognized by IgA antibodies of a few patient s with IgA pemphigus. Considering that subcorneal pustular dermatosis type IgA pemphigus recognizes desmocollin I, autoimmune targets of IgA pemphigus are more heterogeneous than previously considered.