TREM2 and Alzheimer disease: Over the years, plenty of GWAS-defined genes participating in the immune process (APOE, TREM2, CD33, CLU, CR1, ABCA7, EPHA1, MS4As, INPP5D, SPI1, PLCG2, ABI3, HLA-DR15, etc.)have been reported to be associated to AD (Lambert et al., 2009; Seshadri et al., 2010; Hollingworth et al., 2011; Reitz et al., 2013; Tan et al., 2013; Deming et al., 2017; Huang K. L. et al., 2017; Sims et al., 2017; Kunkle et al., 2019).