In other studies, CXCL9/10 have been shown to be highly expressed in RA synovial tissues and fluids (49–52), and the concentration gradient of CXCL9/ 10, between the serum and synovial fluid, favours the migration of CXCR3 receptor-expressing cells from the blood into synovium in RA (50). Here, CXCL9 is linked to rheumatoid arthritis.