As a receptor expressed on microglial cell surface, the ectodomain of TREM2 binds to an array of molecules that are important for AD, including the anionic and zwitterionic lipids, lipoproteins and apolipoproteins, oligomeric Aβ and galectin-3 as reported recently (Atagi et al., 2015; Bailey et al., 2015; Wang et al., 2015; Yeh et al., 2016; Lessard et al., 2018; Zhao et al., 2018; Zhong et al., 2018; Boza-Serrano et al., 2019). The gene discussed is TREM2; the disease is Alzheimer disease.