Finally, in the stratified analysis by RF status, pooled associations were found among RF− RA risk and IL-21 rs6822844 G/T polymorphism [OR = 0.52, 95% CI = 0.32–0.84, Ph = 0.466, P = 0.008 for TT versus GG, and OR = 0.49, 95% CI = 0.31–0.80, Ph = 0.651, P = 0.004 for TT versus GG, Figure 7]. The gene discussed is IL21; the disease is rheumatoid arthritis.