CXCL10 and rheumatoid arthritis: Although it has been shown that TLR4 is involved in the pathophysiology of RA in CIA and K/BxN serum transfer animal models [43, 44], the functional role of TLR4 in CXCL10-mediated production of cytokines contributing to destruction of bone and cartilage during the development of RA remains to be elucidated.