Ultrastructural localization of in vitro binding sites of circulating anti-basement membrane zone antibodies in bullous pemphigoid

Ultrastructural localization of the in vitro binding sites of circulating anti-basement membrane zone antibodies was investigated using two immunoperoxidase methods: the ordinary IgG indirect immunoperoxidase method and the complement immunoperoxidase method. The results indicate that the binding sites of the circulating autoantibodies were diverse. It is postulated that those antibodies demonstrable by the ordinary IgG indirect method and those antibodies possessing capacity to fix complement should bind to different sites of the basement membrane zone. Conventional electron microscopic observation of one lesional skin from bullous pemphigoid confirmed this possibility. (Received December 23, 1982.)