In RA, hyperactivated macrophages increased the expression of toll-like receptors (TLRs), such as TLR2, TLR3, TLR4, and TLR7, which induce synovial inflammation and cartilage destruction by releasing chemokines, pro-inflammatory cytokines, and degradative enzymes have been recognized (26, 27). Here, TLR2 is linked to rheumatoid arthritis.