TREM2 and Alzheimer disease: Aβ plaques and NFTs induce an immune response associated with astroglia and microglia activation and increased inflammatory mediators, tumor necrosis factor α [12], S100, interleukin 1 [13, 14], such as triggering receptor expressed on myeloid cells 2 (TREM2) [15, 16], and complement activation (C1q to C5b-9) [17] in AD [18–20].