HLA antigens and toxicity to gold and penicillamine in rheumatoid arthritis.

One hundred sixty-eight patients with rheumatoid arthritis treated with chloroquine (n = 87), gold salts (n = 133) and/or penicillamine (n = 77) were investigated for possible associations between HLA antigens and toxic reactions. Patients with 2 or more side effects to gold and/or penicillamine had a significantly increased frequency of antigens HLA-B8 and DR3 compared to patients with one or without adverse reactions. Proteinuria to gold or penicillamine was significantly associated with HLA-B8 (relative risk [RR] 4.2) and DR3 (RR 14.0) whereas nonnephrologic side effects to gold or penicillamine were associated with B7 and DR2 (RR 3.5 and 2.8). Patients with skin reactions to gold had a significantly greater frequency of HLA-B7. We found no correlation between chloroquine side effects and any HLA antigen. The results suggest a genetic predisposition to toxic reactions to gold or penicillamine based on an immunologic dysregulation.