In this review, we discuss the role of CD8+ T lymphocytes in various neuroinflammatory pathologies, including common disorders such as AD, PD, multiple sclerosis (MS), and amyotrophic lateral sclerosis (ALS), as well as rare brain disorders such as limbic encephalitis-induced temporal lobe epilepsy (LE-induced TLE) and Susac syndrome (Sus). The gene discussed is CD8A; the disease is Alzheimer disease.