A case of nonscarring inflammatory epidermolysis bullosa acquisita: characterization of IgG autoantibodies by immunofluorescence, immunoblotting and immunogold electron microscopy

We report a case of nonscarring inflammatory epidermolysis bullosa acquisita in a 59-year-old Japanese woman. She developed blisters and erosions on her lip, trunk and extremities. Sodium aurothiomalate was effective for the skin lesions. The patient had been free from bullous skin lesions for the last 13 years and had shown no scarring. Indirect immunofluorescence (IF) study on 1 M NaCl-split skin revealed IgG autoantibodies against the dermal side of the split skin. Immunoblotting using normal human dermal extracts disclosed IgG autoantibodies reactive with the 290 and 145 kD antigens. Circulating IgG autoantibodies were deposited on the lamina densa by immunoelectron microscopy. IF mapping using several antibodies for the components of the basement membrane zone revealed blister formation at the lamina densa. These results suggest that the cleavage at the lamina lucida does not necessarily exclude the diagnosis of EBA and that the definite diagnosis of EBA should be confirmed by immunoblotting or immunoelectron microscopic study.