Under hypoxic conditions, multiple mediators of bone destruction (matrix metallopeptidases (MMPs)), pro-inflammatory factors (interleukin 8 (IL-8) and IL-6), and chemokines (chemokine (C-C motif) ligand 20 (CCL20)) are involved in bone destruction and inflammatory processes in RA (10, 11). Here, CCL20 is linked to rheumatoid arthritis.