Coexistence of psoriasis and linear IgA bullous dermatosis.

Linear IgA bullous dermatosis (LABD) is characterized by IgA autoantibodies against components of the basement membrane zone (BMZ). A 97-kDa protein is one of the major autoantigens associated with this disease. We report a 68-year-old man who developed LABD after a 3-year history of psoriasis and in the context of active hepatitis C virus infection. He had been treated with cyclosporin for psoriasis for about 9 months. Histologically, there was a subepidermal blister containing neutrophils and eosinophils with lymphocytes infiltrating predominantly in the dermis. Direct immunofluorescent staining showed linear IgA deposition at the BMZ. The patient's IgA autoantibodies bound exclusively to the epidermal side of 1 mol/L salt-split normal human skin. Immunoblot analysis identified a 97-kDa autoantigen in epidermal extracts. This appears to be the first case of LABD with IgA autoantibodies against a 97-kDa autoantigen, associated with psoriasis and hepatitis C virus infection.