SOCS3 and rheumatoid arthritis: Suppressive cytokines, such as transforming growth factor-β (TGF-β) and IL-1 receptor antagonist, as well as anti-inflammatory cytokine signaling mechanisms, such as the suppressor of cytokine signaling 3 (SOCS3), are expressed in RA synovium but at levels that are inadequate to block synovitis [146].