Among T cells bearing T cell receptor (TCR) α and β chains (αβ T cells), interferon (IFN)-γ-secreting helper T (Th) 1 cells and interleukin (IL)-17-secreting Th17 cells play pathogenic roles in experimental autoimmune encephalitis (EAE), an animal model of MS (2, 3). Here, IL17A is linked to myeloid sarcoma.