Levels of sTREM2 are increased in the Cerebrospinal fluid and CNS soluble fraction of AD patients (Heslegrave et al, 2016; Piccio et al, 2016; Suárez-Calvet et al, 2019), suggesting a potential role of TREM2 processing by α-secretase in AD pathology. Here, TREM2 is linked to Alzheimer disease.