AIF1 and Alzheimer disease: Fingolimod (FTY720) treatment (for one to two months, starting at five to six months of age) reduced the area of Iba1-positive microglia back to control levels (AD + FTY720: 1.97 ± 0.14%, WT + FTY720: 1.69 ± 0.22%), indicating complete rescue from microgliosis.