Silvin et al. (80) found that the disease associated microglia (DAM) population previously detected in the mouse Alzheimer’s disease model actually includes two different cell lineages: the embryonic derived trigger receptor expressed on myeloid cell 2 (TREM2) dependent DAM expresses neuroprotective characteristics and the monocyte derived TREM2 expresses inflammatory macrophages (DIM) of disease. This evidence concerns the gene TREM2 and Alzheimer disease.