This assay revealed a deficit of chemotaxis in TREM2 KO microglia (Figure 7A), mirroring reports that TREM2 KO microglia are unable to migrate toward amyloid plaques in AD (Cheng-Hathaway et al., 2018; McQuade et al., 2020; Meilandt et al., 2020). This evidence concerns the gene TREM2 and Alzheimer disease.