COMPARATIVE EPITOPE MAPPING OF SERA FROM UNITED-STATES (WS) AND JAPANESE PATIENTS WITH BULLOUS PEMPHIGOID (BP) TO FUSION PROTEINS ENCODED BY BPAG1

Sera from patients with bullous pemphigoid (BP) from the United States (US), Japan, and Britain demonstrate similar reactivity to the major target antigens BPAG1 and BPAG2. The purpose of the present study was to determine if the epitope specificity of circulating autoantibodies in patients with BP from the US and Japan is similar as mapped by bind ing to fusion proteins encoded by BPAG1. Sera from patients and contro ls with BP from the US and Japan were assayed for reactivity to intact BPAG1 and BPAG2 by immunoblot, and to fusion proteins encoded by BPAG 1 by immunoblot and enzyme-linked immunosorbant assay (ELISA). Signifi cant reactivity to fusion proteins encoded by the carboxyl region (FP 16-8) and coiled-coil region (FP3) was seen in sera from the US and Ja panese patients, but not from normal controls from the US or Japan. Se ra from US and Japanese patients differed in their response to FP7, na mely, the reactivity of sera from US patients but not from Japanese pa tients to FP7 was significantly different from the reactivity of their respective control sera. The reasons for this difference in reactivit y are unknown but may reflect genetic or environmental factors relevan t in the generation of an autoantibody response to these target antige ns.