TREM2 and Alzheimer disease: Indeed, we observed increases of plaque-associated AT8 tau pathology in both 5XFAD × TREM2−/− and 5XFAD × TREM2+/− mice relative to the 5XFAD mice with normal TREM2 expression (Fig. 8c), with the latter reaching statistical significance in both the cortex (Fig. 8d) and the subiculum (Fig. 8e), which had the greatest amount of AT8 pathology in the AD-tau-injected 5XFAD mice.