Associations between functional TNFR2 196 M/R polymorphisms and susceptibility to rheumatoid arthritis: a meta-analysis

Several studies have examined the effects of tumor necrosis factor receptor (TNFR) 1 +38 A/G and TNFR2 196 M/R polymorphisms on susceptibility to RA and have reported conflicting results. The purpose of this study was to examine whether the TNFR1 +38 A/G and TNFR2 196 M/R polymorphisms are associated with RA susceptibility. We performed a literature search using the Medical Literature Analysis and Retrieval System Online and Embase citation indices, and conducted a meta-analysis to examine the association between the TNFR1 +38 A/G and TNFR2 196 M/R polymorphisms and RA. Our meta-analysis included a total of 13 studies from 11 articles, consisting of 11 studies of the TNFR2 polymorphism (2,092 cases and 1,483 controls), and two studies of the TNFR1 polymorphism (672 cases and 288 controls). The meta-analysis revealed a significant association between the TNFR2 196 RR genotype and RA risk (OR 1.737, 95 % CI 1.275-2.367, P = 4.6 x 10(-5)). Stratification by ethnicity indicated an association between the TNFR2 196 RR genotype and RA in Europeans (OR 2.054, 95 % CI 1.305-3.232, P = 0.002), but not in East Asians (OR 1.596, 95 % CI 0.642-3.971, P = 0.314). Analysis using a homozygote contrast model showed the same pattern for the TNFR2 196 RR genotype in a European and East Asian population. However, no association was found between the TNFR1 +36 A/G polymorphism and RA in a European population. Our meta-analysis demonstrated that the functional TNFR2 196 M/R polymorphism is associated with susceptibility to RA in the European population.