In view of the “classical” distinction of CD4 T cell subsets, particularly, Th1 and Th17 subsets are involved in the establishment of autoimmune diseases such as multiple sclerosis (MS) and the corresponding rodent model experimental autoimmune encephalomyelitis (EAE), which are thought to be driven by the T cell-released cytokines interleukin-17 (IL-17), interferon-γ (IFN-γ), IL-22, and granulocyte-macrophage colony-stimulating factor (GM-CSF). The gene discussed is IL17A; the disease is experimental autoimmune encephalomyelitis.