Comparative study of bullous pemphigoid antigens among Japanese, British, and U.S. patients indicates similar antigen profiles with the 170-kD antigen present both in the basement membrane and on the keratinocyte cell membrane.

There are a number of controversies relating to studies of bullous pemphigoid (BP) antigens from different institutions, mainly regarding the detection of the 230-kD and 170-kD BP antigens. In this study, in an attempt to resolve the discrepancies, we have examined and compared the reactivity by immunofluorescence, immunoblotting, and immunoprecipitation among the sera from Japanese, British and U.S. BP patients. Both the 230-kD and 170-kD BP antigens were detected by various sera from all populations with immunoblotting, whereas immunoprecipitation detected only the 230-kD BP antigen but not the 170-kD BP antigen. Immunoprecipitation was more sensitive than immunoblotting to detect the 230-kD antigen. These results indicate that both the 230-kD and 170-kD proteins are BP antigens found in all three populations. By immunofluorescence cell surface staining in the lower epidermis in addition to basement membrane zone staining was shown by a considerable number of patients' sera in all populations. Comparison between the results of immunofluorescence and immunoblotting revealed a clear correlation of this cell surface staining with the presence of antibodies against the 170-kD BP antigen. That the affinity-purified antibodies specific to the 170-kD BP antigen showed this cell surface staining further confirmed this correlation. These results may indicate a different nature of the 170-kD BP antigen from that of the 230-kD BP antigen.