LIMITED HETEROGENEITY OF THE HLA CLASS II CONTRIBUTION TO SUSCEPTIBILITY TO RHEUMATOID ARTHRITIS IS SUGGESTED BY POSITIVE ASSOCIATIONS WITH HLA—DR4, DR1 AND DRwlO

Most patients with rheumatoid arthritis (RA) exhibit an HLA class II epitope found on most DR4 and DR1 molecules. We have investigated the possibility of other associations being present in the minority of patients lacking these antigens. One hundred and eighty patients with classical or definite RA and 100 controls were assigned HLA—DR, DQ and DP types by a DNA—based system using sequence—specific oligonucleotides to probe amplified class II alleles amplified by the polymer—ase chain reaction. The expected associations with DR4 (relative risk 10,P