Nowak et al. recently demonstrated that like other T cells cultured in the presence of TGFβ, Th17 cells produce IL9. Th17 cells generated in vitro with IL6 and TGFβ and ex vivo-purified Th17 cells both produced IL9. Data show that IL9 neutralization and IL9R deficiency attenuate the disease, and this correlated with reductions in Th17 cells and IL6-producing macrophages in the CNS. These authors also confirmed the role of IL9 in the development and progression of EAE and implicated Il9 as a Th17derived cytokine that contributes to inflammatory disease [94] .