IL6 and rheumatoid arthritis: In turn, elevated eNAMPT levels induce the expression of pro-inflammatory cytokines (e.g., IL-6 and CXCL8), chemotactic signals (e.g., chemokines of the CXC and CC family) and matrix-degrading enzymes (e.g., MMP-1 and MMP-3) promoting a vicious circle of self-propagating inflammation and destruction of RA joints (25, 183–185).