The MAIT cell subset resulted to represent a low percentage of the total infiltrating T cells in CNS lesions, though the high over-expression of MR1 molecules (that present cognate antigen to MAIT cells), as well as of the activating cytokines IL18 and IL23 suggested that the MS brain represented a suitable microenvironment for MAIT cells pathogenic actions [73]. The gene discussed is IL18; the disease is myeloid sarcoma.