CNTF and rheumatoid arthritis: Although the biological function of CNTF is still largely unknown in OA, recent studies have shown that CNTF-gp130 signaling may be associated with the pathologic bone remodeling evident in rheumatoid arthritis (RA), periodontal disease, spondyarthropathies, and OA through regulating the differentiation and activity of osteoblast, osteoclast, and chondrocytes [36].