Atypical pemphigus with immunoglobulin G autoantibodies against desmoglein 3 and desmocollin 3

In patients with pemphigus vulgaris (PV), pathogenic immunoglobulin (Ig)G antibodies are most commonly directed against desmoglein 3 (Dsg3). It has recently been reported, however, that IgG anti-desmocollin 3 (Dsc3) antibodies are detected in some cases of pemphigus with or without IgG anti-Dsg3 antibodies. We present a case of pemphigus with IgG antibodies against Dsg3 and Dsc3. Subsequent studies showed that the cell surface distribution pattern of Dsc3 but not Dsg3 was altered, suggesting that suprabasal acantholytic blisters were induced by IgG anti-Dsc3 antibodies rather than IgG anti-Dsg3 antibodies. Our case suggests that anti-Dsc3 antibodies may be pathogenic in cases positive for the dual cadherin autoantibodies.