We observed that most granzyme B+ cells in the MS brain co-expressed CD8 and that the fraction of CD8+ T cells expressing granzyme B ranged between 5 and 60% in the different MS cases and brain areas analyzed, the highest values being detected in the perivascular cuffs of active white matter lesions (Figure 7 A, B). This evidence concerns the gene GZMB and myeloid sarcoma.