AIF1 and Alzheimer disease: Adjusting for age and gender, we find that subjects with AD (1) have a significant reduction in the frequency of IBA1+CD74high microglial cells in the frontal cortex (p = 0.0089; Fig. 8d) but (2) have no change in the number of total IBA1 + cells (p = 0.30; Supplementary Fig. 14a).