Early-AD is usually linked to M1 activation, as the Aβ proteins activate the microglia cells by binding pattern recognition receptors (PRRs), such as complement, Fc receptors, CD33, triggering receptor expressed on myeloid cells 2 (TREM2), receptor for advanced glycation endproducts (RAGE), scavenger and TLR receptors, and in this way triggering NF-κB translocation and thus an enhancement of the immune response [24,45,46,47]. This evidence concerns the gene TREM2 and Alzheimer disease.