Case of subepidermal autoimmune bullous disease with psoriasis vulgaris reacting to both BP180 C-terminal domain and laminin gamma-1.

A number of cases of psoriasis vulgaris developing bullous skin lesions have been diagnosed as either bullous pemphigoid with antibodies to the 180-kDa bullous pemphigoid antigen (BP180) non-collagenous 16a (NC16a) domain or anti-laminin-γ1 (p200) pemphigoid. We report a case of subepidermal bullous disease with psoriasis vulgaris, showing antibodies to both BP180 C-terminal domain and laminin-γ1. A 64-year-old Japanese man with psoriasis vulgaris developed exudative erythemas and tense bullae on the whole body but he did not have mucosal involvement. The blistering lesion showed subepidermal blisters histopathologically. In indirect immunofluorescence of 1 mol/L NaCl-split skin, immunoglobulin (Ig)G antibodies reacted with both the epidermal and dermal side. Immunoblotting showed positive IgG with recombinant protein of BP180 C-terminal domain and 200-kDa laminin-γ1 in normal human dermal extract.