IL-10 gene promoter polymorphisms in rheumatoid arthritis

IL-10 is an anti-inflammatory cytokine which may modulate disease expression in RA. Three dimorphic polymorphisms within the IL-10 gene promoter have recently been identified and appear to influence regulation of its expression. The -1082* A allele has been associated with low and the - 1082* G allele with high in vitro IL-10 production. We have analysed 117 unrelated Caucasoid RA patients and 119 ethnically marched controls. No significant differences in the allele frequencies of the three polymorphisms were found between controls and RA patients. In contrast, a significant association between the -1082* A allele and the (-1082*A/-819*C/-592*C) haplotype and IgA RF+ve/IgG RF-ve were patients was observed. The association of genotypes encoding low IL-10 production with IgA RF in RA is incompatible with its suggested role in antibody isotype switching. IgA RF has been associated with severe RA and may thus be indirectly correlated with a genotype encoding low IL-10 production.