Anti-laminin 5 mucous membrane pemphigoid

A 70-year-old patient presented erosions on the oral mucosa and skin, predominantly in perianal and inguinal areas. Histopathologically, subepidermal blistering was observed. By direct immunofluorescence microscopy, linear deposits of IgG and C₃ were seen at the dermal-epidermal junction. By indirect immunofluorescence microscopy, binding of IgG autoantibodies to the dermal side of NaCI-split skin was detected. These autoantibodies were shown to target both the non-processed and processed α₃- as well as the β₃-subunit of laminin 5 by immunoblot analysis using extracellular matrix of cultured human keratinocytes. Based on these results, the diagnosis of an anti-laminin 5 mucous membrane pemphigoid was established. Oral treatment with dapsone, combined with intravenous dexamethasone pulse therapy, led to rapid improvement.