IL17A and rheumatoid arthritis: In CIA mice, the depletion of MDSCs in vivo led to the inhibition of T cell proliferation and reductions in IL-17A and IL-1β production, while adoptive transfer of MDSCs could lead to increased disease severity in mice, including joint swelling, cell infiltration, bone erosion, and cartilage destruction, and significantly increased serum IL-17A and IL-1β levels, which suggests that MDSCs play important roles in the development of RA and CIA (30).