The aim of the present study was to examine the association between polymorphisms of IL-10 with inflammatory biomarkers in East Chinese Han patients with rheumatoid arthritis (RA).

We examined IL-10 rs1800872 A/C polymorphisms in 615 RA patients, and 839 controls, in an East Chinese Han population. Genotyping was performed using a custom-by-design 48-Plex SNP scan TM Kit. The blood plasma concentration of IL-10 was measured using an Iodine [¹²⁵I] IL-10 Radioimmunoassay Kit, in 90 RA patients and 90 controls.

IL-10 rs1800872 A/C polymorphisms were associated with risk of RA. Following stratified analysis, an increased risk of RA was associated with the CC genotype among male, older, C-reactive protein-positive, anti-cyclic citrullinated peptide antibody-positive, and rheumatoid factor-positive-patients, and among patients with a DAS28 of≥3.20 or an erythrocyte sedimentation rate of≥25, and in functional class I and II patients. The average plasma concentration of IL-10 was significantly higher in RA patients compared with controls. RA patients positive for the homozygote CC were characterized by significantly higher levels of IL-10 compared with patients with the heterozygote AC. We also found that there were significant relationships between the single nucleotide polymorphisms in the human IL-10 rs1800872 A/C and production of IL-10.

Our results suggest that the IL-10 rs1800872 A/C allele might increase the risk of RA. The IL-10 rs1800872 A/C allele might also impact the inflammatory reaction of IL-10 in patients with RA.