There is evidence that cytokines secreted by activated CD4+ T helper 1 (Th1) and Th17 cells, including interferon (IFN)-γ, interleukin (IL)-17 and tumor necrosis factor (TNF)-α, play a critical role in the immune pathogenesis of MS and its animal model EAE [12]. The gene discussed is IL17A; the disease is myeloid sarcoma.