Association between IL1B polymorphisms and the risk of rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic, inflammatory synovitis dominated systemic disease with unknown etiology. The purpose of this study was to determine the relationship between IL1B polymorphisms and RA risk in a Chinese Han population. Four single-nucleotide polymorphisms (SNPs) of IL1B, rs2853550, rs1143643, rs3136558 and rs16944 were genotyped in 508 RA cases and 494 healthy controls using the Agena MassARRAY method. A genetic model analysis was performed to evaluate the relationships between the variants and RA risk. Haplotype analysis was used to evaluate the potential relationship between the genetic block and RA risk. We determined that rs1143643 was linked to a reduced risk of RA based on the results of the co-dominant model (OR = 0.67, 95%CI: 0.50-0.89, p = 0.006) and the dominant model (OR = 0.73, 95%CI = 0.56-0.96, p = 0.025). On the other hand, rs16944 was associated with an increased risk of RA in the co-dominant model (OR = 1.71, 95%CI = 1.53-1.97, p = 0.029) and the recessive model (OR = 1.41, 95%CI = 1.05-1.88, p = 0.021). Among individuals older than 50 years, we observed that rs2853550 was associated with an increased risk of RA, and that rs1143643 decreased RA risk. Furthermore, rs1143643 was associated with a decreased RA risk in female patients. However, rs16944 increased RA risk in both the co-dominant and the additive models in different age subgroups. In addition, rs16944-GA increased RA risk in males in the co-dominance model and rs16944-AA increased RA risk in females in the additive model. These results suggested that rs2853550, rs1143643, and rs16944 in the IL1B gene are associated with RA risk.