IL17A and autoimmune disease: Adoptive transfer of myelin oligodendrocyte glycoprotein (MOG)-specific Th9 cells into Rag1−/− mice sufficiently induces EAE more severe than transferring Th1 cells.742,743 IL-9 deficiency or neutralization exhibit attenuated EAE progression with reduced infiltration of Th17 cells and pro-inflammatory macrophages in the CNS, as well as decreased IL-17 and IFN-γ levels.744,745 Strikingly, cooperative functions of Th9 and Th17 cells have been revealed during autoimmune disorders.