CCL2 and rheumatoid arthritis: Among the chemokines that play an important role in inflammation, including RA, are regulated upon activation, normal T cell expressed, and secreted (RANTES), also known as chemokine C-C motif ligand 5 (CCL5); monocyte chemotactic protein-1 (MCP-1), or CCL2; macrophage inflammatory protein-1α (MIP-1α), or CCL3; and growth regulated oncogene-keratinocyte chemoattractant (GRO/KC), or chemokine C-X-C motif ligand 1 (CXCL1) [12–15].