CCL4 and rheumatoid arthritis: For that, PBMCs (from the same RA patients and control group enrolled in our former study [21]) were cultured alone or in the presence of allogeneic BM-MSCs, in order to investigate the influence of BM-MSCs on the protein levels of TNF-α, CD83, CCR7, and CCL4 (or macrophage inflammatory protein, MIP-1β) by mDCs and monocyte subpopulations (classical, intermediate, and non-classical monocytes).