Association between HLA-DR4 and production of collagen-specific antibodies in Israeli patients with rheumatoid arthritis.

Antibodies to native human Type I + III collagen were measured by a radioimmunoassay in sera samples of 42 rheumatoid arthritis (RA) patients. Sixteen patients (38%) had significant antibody titers. Although the frequency of HLA-DR antigens of RA patients did not differ from that of the random Israeli population, there was a significant association (P less than 0.01) between the presence of collagen antibodies and HLA-DR4.