DR antigen distribution was studied in 85 Blacks with either classical or definite rheumatoid arthritis (RA). Sixty-three were seropositive and 22 were seronegative by latex fixation titer. The frequency of DR4 was 7.41% in our control Black population (n=162), 22.22% in the seropositive (0.01 > p > 0.001; RR 3.57) and 22.72% in the seronegative RA (0.01 > p > 0.001: RR 3.67). Our data confirm the association of DR4 with seropositive RA in Blacks, and suggest a similar association of DR4 with seronegative RA. It also suggests that DR4 may be a risk factor for more aggressive disease in Blacks with seropositive RA.
