The fact that total RUNX3+ and EOMES+ CD8+ memory T cells, but not RUNX3+EOMES+T-bet− coexpressing cells, accumulated in the circulation of MS patients after natalizumab treatment indicates that other transcription factors such as BLIMP-1 could be especially relevant to better define this brain-homing subset. This evidence concerns the gene PRDM1 and myeloid sarcoma.