Through the participation of soluble factors, MSCs enhance the anti‐inflammatory phenotype of macrophages and inhibit their pro‐inflammatory phenotype.[67] IL‐1 receptor antagonist (IL‐1Ra) is critical in the MSCs‐mediated macrophage polarization.[50] In addition, MSCs also promote IL‐10 secretion and inhibit IL‐12 and TNF‐α secretion in macrophages.[68] The above effects of MSCs on macrophages have been verified in RA. This evidence concerns the gene TNF and rheumatoid arthritis.