CCL21 and rheumatoid arthritis: Genetic susceptibility to higher plasma levels of ICOSLG, ERBB2, ALDH2, FCGR3A, PAM, TNFAIP3, CD40, MFAP2, BCL2L15, HAPLN4, SUGP1, FCRL3, OLFML3, PADI4, WASL, POLR2F, IGSF11, and ADPGK correlated with increased RA risk, while NFKBIE, CCL21, IL6R, CD28, FCGR2A, FLT3, IFNGR2, SPRED2, CCL19, CELF2, H2AZ1, H2BC21, H2AC25, and H2BC26 showed inverse associations (Figure 2).