From the aforementioned published studies and our own data, it is still not possible to determine if the effect of TREM2 deficiency on astrocytes in AD models is secondary to the effect of TREM2 on amyloid or tau pathology that subsequently affects the astrocytic response or if TREM2 deficiency has a non-cell-autonomous effect on astrocyte responses. Here, TREM2 is linked to Alzheimer disease.