Comparison of single nucleotide polymorphisms in the human interleukin-10 gene promoter between rheumatoid arthritis patients and normal subjects in Malaysia.

In this study, three single nucleotide polymorphisms (SNPs) located within the promoter of the human interleukin (IL)-10 gene [rs1800896 (position: -1087G>A), rs1800871 (position: -824C>T) and rs1800872 (position: -597C>A)] were investigated in 84 rheumatoid arthritis (RA) patients and 95 age- and sex-matched healthy subjects using polymerase chain reaction-restriction fragment length polymorphism method. Production of IL-10 by peripheral blood lymphocytes from the RA patients and healthy subjects cultured in the presence of Concanavalin A (Con A) was determined by using enzyme-linked immunosorbent assay. The results show that the distribution of the IL-10 genotypes did not differ significantly between RA patients and healthy subjects (P>0.05). However, a significant difference was observed in allele frequencies of -824CT, -824TT, -597CA, and -597AA between the RA patients and healthy volunteers (P=0.04). The -1087A/-824T/-597A (ATA) haplotype, which comprises all mutant alleles, was associated with lower IL-10 production when compared with the other haplotypes. In contrast, the RA patients who did not display the ATA haplotype produced significantly higher levels of IL-10 when compared with those carrying either one (P=0.012) or two (P=0.005) ATA haplotypes. Our findings suggest that there is an association between SNPs in the promoter of the human IL-10 gene and susceptibility to RA.