Racial differences in the distribution of systemic sclerosis–related serum antinuclear antibodies

Abstract

Objective. To determine racial differences in the frequencies of systemic sclerosis (SSc)–related serum antinuclear antibodies (ANA). Methods. We tested serum samples from 275 Japanese, 416 North American Caucasian, and 24 North American black SSc patients for 8 SSc-related serum ANA, using indirect immunofluorescence, double immunodiffusion, and radioimmunoprecipitation assays. Results. In comparing the 3 racial groups, we found that anti–U1 RNP, anti–RNA polymerase I, II, and III, and anti–U3 RNP antibodies were the most frequently detected antibodies in Japanese, Caucasian, and black patients, respectively. Anti–PM-Scl antibody was found exclusively in Caucasians. Conclusion. The production of SSc-related serum ANA is related to immunogenetic background.