For example, the +49 A/G (rs231775) polymorphism in cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) is associated with RA susceptibility in Asians, and the -174 G/C (rs1800795) polymorphism in IL-6 is correlated with RA susceptibility in Europeans [19]. This evidence concerns the gene IL6 and rheumatoid arthritis.