HLA-D region antigens in patients with rheumatoid arthritis.

We studied the distribution of HLA-D region antigens in 2 groups of rheumatoid arthritis (RA) patients: those with mild, nonprogressive disease, and those with severe disease. The results demonstrate that DR4 was significantly increased in both RA patient populations. The frequencies of DR1 and DR4-associated DQw7 alleles, however, were different in these 2 groups of patients. DR1 was significantly increased only in patients with mild RA, and DR4-associated DQw7 was significantly increased only in patients with severe disease. The results of the present study, together with previous data from our laboratory and from other investigators on the incidence of HLA-D region antigens in RA, suggest that both DR and DQ (A and B) genes may be important in conferring susceptibility to RA; DR in the mild forms of the disease, and DQ in severe RA.