Linear IgA bullous dermatosis with circulating IgG autoantibodies to the 230 kD epidermal antigen

The patient was a 54-year-old woman with wide-spread bullous lesions on her trunk and oral mucosa. Histologic examination revealed a subepidermal blister with infiltration of neutrophils and eosinophils. Direct immunofluorescence showed an exclusively IgA deposition at the basement membrane zone (BMZ). Indirect immunofluorescence showed that the blister fluid, but not the serum, contained IgG antibodies against the BMZ antigen on the epidermal side of salt-split skin. Using immunoblot analysis with normal human epidermal extracts, both serum and blister fluid reacted with the 230 kD epidermal antigen. Using colloidal gold and direct immunoelectron microscopy, IgA deposition was detected in the lamina lucida. Clinically, the skin lesions responded well to dapsone. We diagnosed this case as linear IgA bullous dermatosis (LABD) with IgG class circulating autoantibodies against the epidermal 230 kD antigen. These antibodies were considered to be secondary to the damage to the epidermal basal keratinocyte in this case.