TNF and rheumatoid arthritis: The pro-inflammatory nature of RA MDM is now well-established, with secretion of CXCL4 and CXCL7 to attract neutrophils and monocytes to the inflamed joint (61) and release of cytokines such as TNF-α, IL-1, IL-6, GM-CSF and TGF-β are well-documented (62–64).