IL6 and rheumatoid arthritis: In addition, BM-MSCs can also inhibit the production of inflammatory cytokines (TNF-α, IL-17, IL-6, IL-2, IFN-γ, and IL-9) via T-cells in RA [43], and MSCs restores the immune response by enhancing Treg/Th17 cell ratios and regulating TGF-β and PGE2 [44,45].