Specific target antigens have been identified in many autoimmune syndromes, and most of these diseases are caused by single target antigens. However, 2 or more target antigens are known to be involved in mucous membrane pemphigoid, which can exhibit various clinical characteristics.
We report a case of anti-BP180-type mucous membrane pemphigoid that was difficult to distinguish from bullous pemphigoid on the basis of immunological analysis. The patient was a 76-year-old man who visited our department because of gum erosion and pain. Sore gums and ulcers were observed on both the upper and lower jaws, and mild pruritic erythema was noted on the posterior wall of the oral cavity. Direct immunohistological analysis of tissues obtained from the affected jaw showed deposition of IgG and C3 in the basal membrane. An enzymelinked immunosorbent assay（ELISA）for BP180 and BP230 showed positive results, and an immunoblot assay using the recombinant BP180 protein showed positive results. In addition, an immunoblot assay using the recombinant BP180 protein showed positive results for IgG antibodies against BP180 NC16a and negative results for IgG antibodies against the C-terminal portion of BP180. The patient was suspected to have bullous pemphigoid, but because the main clinical findings were pathologic changes of the oral mucosa, the patient was given a diagnosis of anti-BP180-type mucosal pemphigoid. The symptoms improved with an improvement in oral hygiene and the application of a steroid.
