TLR4 and rheumatoid arthritis: Chemerin has been hypothesized to stimulate synovial fibroblasts motility and leukocyte migration into the joint, as well as the expression of IL-6, MCP1, MMP-3, and Toll-like receptor 4 (TLR4) in synovial fibroblasts from RA patients (Conde et al., 2011; Kaneko et al., 2011; Eisinger et al., 2012).