CD8+ T cells directly attack oligodendrocytes (via the secretion of granzymes and perforin), causing apoptosis and damaging neurons via the release of cytolytic granules, leading to axonal dissection.28 Up to a quarter of CD8+ T cells in the active lesions of MS patients can produce IL-17 and are thought to be mucosa-associated invariant T (MAIT) cells. The gene discussed is CD8A; the disease is myeloid sarcoma.