CCL2 and rheumatoid arthritis: One FLS subtype, characterized by the presence of CD34 and cadherin 11 (CDH11) and the absence of THY1/CD90, was implicated in monocyte recruitment in the RA synovium through secretion of IL-6, CXCL12 (C-X-C Motif Chemokine Ligand 12) and CCL2 (C-C Motif Chemokine Ligand 2) [9,69].