Th1 cells were initially considered to be responsible for EAE and MS immunopathogenesis, as IFN‐γ was abundant in CNS lesions (Merrill et al. 1992; Traugott and Lebon 1988) and the administration of this cytokine to MS patients exacerbated the disease (Panitch et al. 1987). The gene discussed is IFNG; the disease is myeloid sarcoma.