It has been suggested that CD8+ T cells in lesions from patients with relapsing, progressive and fulminant acute MS show features of tissue-resident memory cells and play a central role in the establishment of tissue-specific immunological memory, propagating chronic compartmentalized inflammation and tissue damage in the MS brain by local activation following re-exposure to their cognate antigen (Machado-Santos et al., 2018). This evidence concerns the gene CD8A and myeloid sarcoma.