The observations that MAIT cells may be higher in cerebrospinal fluid than peripheral blood in RR-MS during exacerbation (9) and that activated CD8+CD161+Vα7.2+ T cells are detected in active and chronic active lesions of secondary progressive MS cases (20) may indicate recruitment of circulating MAIT cells into the CNS. Here, KLRB1 is linked to myeloid sarcoma.