In prodromal AD, microglial activation might have a protective role by clearing amyloid.2,8,9 Microglial activation is characterized by upregulation of the mitochondrial translocator protein, TSPO.10,11 Studies using the microglial marker [11C](R)PK11195-PET have demonstrated increased microglial activation in late AD, which correlated inversely with memory performance.12 However, the role of microglial activation in the early stages of neurodegenerative diseases is still debated. This evidence concerns the gene TSPO and Alzheimer disease.