Similarly, a consistent finding is that the numbers of CD4+ and CD8+ T cells in the brain parenchyma and cerebrospinal fluid (CSF) of AD patients are significantly higher than normal, with CD8+ T cells having the advantage over CD4 + T cells in absolute numbers, and that both subtypes exhibit the CD45RA‐CD45RO+ phenotype (Ferretti et al., 2016; Laurent et al., 2017; Merlini et al., 2018; Rogers et al., 1988; Togo et al., 2002), indicating that infiltrating T cells were activated and may be cytotoxic. The gene discussed is CD8A; the disease is Alzheimer disease.