CD8A and Alzheimer disease: Finally, given that Trm “sessile” cells were found among CD8+ T cells in AD, and particularly in relapsing-remitting and progressive MS (123, 161, 164–166, 197, 198) and that drugs inhibiting T-cell recruitment into the brain in MS showed limited therapeutic efficacy (123), the role of CD8+ Trm cells in the progression of MS and AD should be examined.