CXCR2 and rheumatoid arthritis: The remaining genes, which include CKLF, CXCL10, CXCR1, CXCR2, CXCR6, IL12RB2, IFNG, TLR3 and ICAM-1, did not show any significant differential expression between the NK cells of RA patients and healthy controls (Figure 4C).