Pemphigus foliaceus induced by exposure to sunlight - Report of a case andanalysis of photochallenge-induced lesions

Background: Although there are many reports on photo-ind uced pemphigus, ca reful analysis in the development of acantholytic blister have rarely been performed in the lesions induced by photochallenge. Objective: The study wa s intended to elucidate the mechanisms by which ultraviolet light (UV) radi ation causes the skin lesions of pemphigus foliaceus. Methods: Photochallen ge-induced lesions were examined histologically and immunohistochemically o ver the time course with three biopsy specimens. Neutrophil adhesion assay was performed using the specimens prepared from the photochallenged lesions as substrates. Results: A small number of neutrophils were seen at 5 h aft er photochallenge in the dermis and epidermis, and slight acantholysis was detected at 72 h. In neutrophil adhesion assay, greater numbers of neutroph ils adhered to the upper epidermis of the skin obtained at 5 h after challe nge. Conclusions: Our results suggest that both enhanced binding of autoant ibodies to the epidermis after UV radiation and preferential adhesion of ne utrophils to the UV-irradiated epidermis contribute to the development of a cantholysis in photo-induced pemphigus foliaceus. Intercellular adhesion mo lecule-1 (ICAM-1) expression on keratinocytes is not primarily responsible for the epidermal migration of neutrophils. Copyright (C) 2000 S. Karger AG , Basel.