To investigate which HLA haplotypes identified by DRB1 or tumor necrosis factor (TNF) microsatellite markers are associated with adverse reactions to parenteral gold injections.
We retrospectively studied 193 Caucasian subjects with rheumatoid arthritis (RA) who had received parenteral gold injections from a university faculty outpatient practice (n = 163) and outpatient clinics at a Department of Veterans Affairs Medical Center (n = 30). DRB1 typing was done by several DNA based techniques. TNF microsatellite genotypes were derived by polymerase chain reaction amplification, sequencing-type gel electrophoresis, and silver staining.
Seventy-six subjects had experienced adverse reactions to gold injections (other than nitritoid reactions), 18 of whom had 2 concurrent toxicities. The numbers with adverse reactions included: mucocutaneous (57), proteinuria (25), hematuria without proteinuria (5), thrombocytopenia (3), and miscellaneous (11). By frequency comparisons, no DR was associated with adverse reactions to parenteral gold (chi-squared 4.7, 6 df, NS). Specifically, there was no increased risk of proteinuria or mucocutaneous side effects in the DR3 positive RA group, almost all of whom had the DRB1 allele *0301. By logistic regression modeling controlling for sex and onset age, DR12 and the TNF microsatellite markers a5b5 and a6b5 were associated with mucocutaneous reactions (p < 0.05 for each). The odds ratios favoring mucocutaneous adverse reactions were 3.72 with TNFa5b5 and 2.03 with TNFa6b5. TNFa5b5 was commonly found on the HLA haplotypes bearing DRB1*0101, and TNFa6b5 was on the ones bearing DRB1 alleles of the DR1, DR2, DR3, DR5, or DR6 groups or the DRB1*0401 allele.
HLA haplotypes conferring risk of gold induced mucocutaneous reactions were better identified by certain HLA class III markers, namely TNFa5b5 and TNFa6b5, than by any previously associated DR groups.