HLA antigens and gold toxicity in American blacks with rheumatoid arthritis.

An increase in the frequency of DR3 in rheumatoid arthritis (RA) patients exhibiting toxic reactions to gold salt (GS) therapy has been observed in several studies of Caucasoid patients. Likewise, the association of B35 with gold-induced mucocutaneous reactions has also been reported in Caucasoid RA patients. Similar studies in other ethnic groups have not been previously documented. The present study was performed in American black RA patients receiving GS to determine if there were similar HLA associations with toxic reactions as those reported in Caucasoids. Eight-two seropositive and 18 seronegative American black RA patients were studied. Forty-one of the seropositive (50.0%) and six of the seronegative (33.3%) developed a toxic manifestation. No significant differences in the frequency distribution of HLA-B8, HLA-B35, DR, or DQw antigens were observed between the patients who had a toxic reaction and those who did not in either the seropositive or the seronegative RA patients. In particular, DR3 was not increased in patients with renal toxicity and B35 was not increased in patients with mucocutaneous reaction. Our study demonstrates that American black RA patients exhibiting GS toxicity do not have the same HLA associations as Caucasoids. The possibility that other genetic factor(s) may account for the occurrence of gold salt toxicity in American blacks requires further investigation.