Bullous dermatosis associated with IgG antibodies specific for desmocollins

We describe a 53-year-old man with a two-year history of bullous disease. He had also had stage IV gastric cancer for 3 years. He presented with cutaneous erythemas and blisters, showing an annular arrangement. Histopathological examination revealed intraepidermal pustules of eosinophils and neutrophils without apparent acantholysis. Indirect immunofluorescence (IIF) analysis showed IgG anti-keratinocyte cell surface antibodies. The result of IIF on rat bladder was positive. IgG enzyme-linked immunosorbent assays failed to detect antibodies to either anti-desmoglein-1 (Dsg1), Dsg3, or BP180. Immunoblot analysis with normal human epidermal extract revealed IgG reactivity with 120, 110, and 100 kDa species. Immunofluorescence analysis using COS-7 cells that expressed desmocollin (Dsc) 1, 2, and 3 demonstrated that IgG autoantibodies in the patient's serum reacted with all Dsc1-3. A heterogeneous autoantibody profile including IgG reactivity against Dsc1-3 implicated association with cancer-related pemphigoid, although the findings did not fulfill the diagnostic criteria of paraneoplastic pemphigus. A review of the literature revealed that rare autoantibodies to Dsc, most of which were IgA class, were detected in 7 reported bullous diseases. In 5 out of 7 cases, they were combined with autoantibodies to bullous pemphigoid or pemphigus vulgaris. This is the first case that has IgG autoantibodies to all Dsc1~3.