APOE and Alzheimer disease: More recently, the Holtzman team utilized APPPS1:E4 and APPPS1:E3 mice to investigate the effects of APOE4 in the context of sleep deprivation in AD and identified less phagocytic and plaque-associated microgliosis and greater levels of dystrophic neurites in the presence of the APOE4 allele compared to APOE3 [171].