CD8 T cells accumulating in brain tissue of MS patients are mainly effector memory T cells (CD45RA-, CD45RO+, CCR7-) that express the activation marker CD69, the costimulatory molecule CD137 and the apoptosis inducing TNF family member CD95L, and produce IFNγ (62, 114, 117). The gene discussed is IFNG; the disease is myeloid sarcoma.