CXCR4 and rheumatoid arthritis: However, we consider our data to be convincing because the induction of major mediators of inflammation (COX-2, PGES, ADORA2A, IL-1β, IL-6, CXCL8 and CXCR4) and cartilage destruction (MMP10 and MMP12) and the repression of key ECM components (COMP and CSPG2) are most probably important reasons for chondrocyte dysfunction in RA-related destruction of cartilage.