BACKGROUND: There are a large number of autoimmune bullous diseases, which have distinct autoantibodies. Several reports on cases with IgG autoantibodies against a novel 200 kDa dermal protein have been published, for which we suggested the term, anti-p200 pemphigoid. However, the nature of this 200 kDa antigen has not been well characterized. OBJECTIVE: In this study, we examined the relationship between the 200 kDa protein and type VII collagen. METHODS: We collected sera from 12 cases of anti-p200 pemphigoid and skin sections from six cases of recessive dystrophic epidermolysis bullosa (RDEB). The reactivity of these sera was examined by indirect immunofluorescence using sections of the disease skin. RESULTS: we have shown that all the 12 anti-p200 pemphigoid sera could react with basement membrane zone of five cases of RDEB, while epidermolysis bullosa acquisita (EBA) sera were negative in these skins. In addition, in a case of RDEB, EBA sera reacted with intracytoplasmic deposition of type VII collagen, while no anti-p200 pemphigoid sera showed this reactivity. CONCLUSION: These results strongly suggested that the 200 kDa antigen is not a fragment of type VII collagen, but a specific autoantigen.
BACKGROUND: There are a large number of autoimmune bullous diseases, which have distinct autoantibodies. Several reports on cases with IgG autoantibodies against a novel 200 kDa dermal protein have been published, for which we suggested the term, anti-p200 pemphigoid. However, the nature of this 200 kDa antigen has not been well characterized. OBJECTIVE: In this study, we examined the relationship between the 200 kDa protein and type VII collagen. METHODS: We collected sera from 12 cases of anti-p200 pemphigoid and skin sections from six cases of recessive dystrophic epidermolysis bullosa (RDEB). The reactivity of these sera was examined by indirect immunofluorescence using sections of the disease skin. RESULTS: we have shown that all the 12 anti-p200 pemphigoid sera could react with basement membrane zone of five cases of RDEB, while epidermolysis bullosa acquisita (EBA) sera were negative in these skins. In addition, in a case of RDEB, EBA sera reacted with intracytoplasmic deposition of type VII collagen, while no anti-p200 pemphigoid sera showed this reactivity. CONCLUSION: These results strongly suggested that the 200 kDa antigen is not a fragment of type VII collagen, but a specific autoantigen.