Association of HLA-Aw31 and HLA-DR1 with adult rheumatoid arthritis.
Forty-nine Israeli Jewish patients with rheumatoid arthritis (RA) were studied for their HLA A, B, C, DR antigen frequency. A significant increase in HLA Aw31 and HLA DR1 was observed (p less than 5.10(-5) and p less than 5.10(-3) respectively). 45% of Aw31 positive patients were sero-negative for rheumatoid factor, while most HLA DR1 positive individuals were seropositive. DR5 was found to be significantly decreased (p less than 5.10(-4)). Contrary to previous reports, DRw4 was found to be within the range of antigen frequency of the controls (34.7% vs. 32%). It is suggested that in our population of patients Aw31 and DR1 and not DR4 are highly associated with adult onset of RA.