HLA antigens and toxic reactions to sodium aurothiomalate in patients with rheumatoid arthritis.

HLA typing studies were performed on 60 consecutive patients with seropositive definite or classical rheumatoid arthritis (RA). Patients were treated with gold and were followed for a minimum of 18 months for identification of adverse reactions to gold therapy. HLA-DR3 was increased significantly in patients who developed gold induced rash, proteinuria or thrombocytopenia. On the other hand, the incidence of HLA-DR4 was lower in patients with these adverse reactions. Our results demonstrate that patients with RA carrying DR3 are at a higher risk of developing adverse reactions to gold. The most interesting finding was the low incidence of DR4 in patients who developed adverse reactions to gold, suggesting that DR4 positive patients may have some degree of protection against gold toxicity.