The eQTLs acting on 3 genes (METTL21B, IKZF3, and JAZF1) were unique to CD4+ T lymphocytes in this population, with PADI4 also subject to a convincing effect exclusively in this cell type despite falling marginally short of the α = 10% threshold by permutation analysis; the latter gene encodes a peptidylarginine deiminase enzyme, and therefore is of interest in the pathogenesis of RA 28. Here, PADI4 is linked to rheumatoid arthritis.