Brain tissue from a rodent model of AD and AD patients demonstrate that innate (e.g., macrophages, monocytes, neutrophils) and adaptive (i.e., T cells) immune cells can infiltrate the CNS and accumulate near areas of Aβ and tau pathology (Fiala et al., 2002; Baik et al., 2014; Merlini et al., 2018; Gate et al., 2020). This evidence concerns the gene MAPT and Alzheimer disease.