There were 4 studies involving 2094 cases and 1591 controls that reported the relationship between rs36084323 (PD-1.1 G/A) polymorphism and RA.[19–22] Three studies involving 1382 cases and 3720 controls focused on the relationship between rs11568821 (PD-1.3 G/A) polymorphism and RA.[18–21,23] Another 3 studies including 1985 RA cases and 1400 controls studied the relationship between rs2227981 (PD-1.5 C/T) polymorphism and RA.[19,21,22] Moreover, rs11568821 (PD-1.3 G/A) was nonpolymorphic in Asians and so was rs2227981 (PD-1.5 C/T) in Caucasians. The gene discussed is PDCD1; the disease is rheumatoid arthritis.