CREG antigens differentially influence expression of extraarticular manifestations in whites and blacks with rheumatoid arthritis.

B27 and the CREG antigens (-7, -27, -40, -42, and -22) have been shown to be related to the spondyloarthropathies. We have studied the frequency distribution of these antigens in patients with RA. Two hundred ninety-six patients with either classical or definitive RA by ARA criteria were studied: 199 were whites and 97 were blacks. Appropriate local control subjects were also studied (242 whites and 283 blacks). In the white RA patients 48.7% possessed a CREG antigen (97 of 199) while in the black patients 28.9% were CREG positive (28 of 97). In the white control subjects, 45.9% had a CREG antigen and 31.4% for the black control subjects. The relationship between CREG antigens and disease expression was compared using clinical, demographic, radiologic, and therapeutic parameters. For the white group there was no difference in the age and sex, disease duration, functional capacity, anatomic grading, C/M ratio, seropositivity, frequency of extraarticular manifestations (subcutaneous nodules, vasculitis, sicca symptoms, pleuropulmonary, or pericardial disease), frequency of remittive therapy, and toxicity to chrysotherapy. For the blacks all parameters were comparable except for a decrease in the frequency of extraarticular manifestations among the CREG-positive patients (21.4 vs. 46.4%) which is significant (p less than 0.05). Our data show no significant differences in the frequency of the CREG antigens in either blacks or whites with RA as compared to normal subjects. However, a possible sparing of some of the extraarticular manifestations of the disease appears to associate with the CREG antigens.