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.