Autoantibodies Against Multiple Epitopes in Bp180 and Laminin Gamma-1 in Subepidermal Blistering Skin Disease Associated with Psoriatic Erythroderma

We report a 79-year-old Japanese man who developed subepidermal blistering skin disease after an 8-year history of psoriasis. Histology of a bullous lesion revealed a subepidermal blister with a mixed inflammatory cell infiltrate and fibrin nets. Indirect immunofluorescence using normal human skin sections revealed IgG and IgA autoantibodies in the patient serum, which bound to the epidermal side of 1M NaCl-split skin sections. Immunoblot analysis revealed that both IgA and IgG antibodies reacted with the BP180 NC16a domain and the 120-kDa LAD-1 and that IgG antibodies also reacted with the BP180 C-terminal domain and laminin gamma-1. These findings indicated that autoantibodies to laminin gamma-1 and multiple epitopes in BP180 ectodomain played a role in the pathogenesis of this unique autoimmune subepidermal blistering skin disease associated with psoriasis.