In addition, prostaglandin E2 (PGE2), CCL2 and interleukin 1 receptor antagonist (IL1RA), which are produced by MSC have shown to have an important role in the therapeutic effects of MSC on autoimmune diseases, such as rheumatoid arthritis [3, 4, 20–23]. This evidence concerns the gene CCL2 and rheumatoid arthritis.