Recently, Gate et al. [30] suggested a role for the adaptive immune system in blood and cerebrospinal fluid in AD based on a small number of clonal, antigen-experienced specialised CD8+ T effector memory CD45RA+ (TEMRA) cells patrolling intrathecal cerebrospinal fluid (CSF), as well as CD8+ T cells in the hippocampus near beta-amyloid plaques. Here, CD8A is linked to Alzheimer disease.