It was shown that some of the brain-infiltrating CD8 T cell clones persist for several years in the CSF and/or blood of MS patients (81) and that clonal CD8 T cells in the blood show a bias towards a memory phenotype with higher expression of CCR5, CD11a and granzyme B, compared to the non-oligoclonal counterparts (133). This evidence concerns the gene GZMB and myeloid sarcoma.