CLEC6A and rheumatoid arthritis: Among all these immune mediators, MCP-1/CCL2, a chemokine highly expressed in the synovial fluid of RA patients [7], binds to CCR2 and promotes the recruitment of antigen-presenting cells and T cells [8] whereas C-type lectins such as Dectin-1, Dectin-2 and DC-SIGN regulate the monocyte-induced T-cell activation in the RA synovium [5], [6].