Potent chemokines, such as monocyte chemoattractant protein-1 (MCP-1)/C-C motif chemokine ligand (CCL)2, regulated upon activation, normal T-cell-expressed and, presumably, secreted (RANTES)/CCL5, and C-X-C motif chemokine ligand (CXCL)9 and CXCL10, were found to be significantly elevated in the SF of patients with JIA, driving the chemotactic activity of mononuclear leukocytes [19,20]. Here, CCL2 is linked to juvenile idiopathic arthritis.