AIF1 and Alzheimer disease: The observed 2.5-fold increase in this normalized Iba1 intensity in vehicle treated APP/PS1 mice compared to WT littermates (WT vehicle: 0.50 ± 0.07, WT + FTY720: 0.46 ± 0.08, AD vehicle: 1.30 ± 0.25, AD + FTY720: 0.48 ± 0.05) was similar as compared to the increase in microglia area (threefold increase; Figure 4C, left).