APP and Alzheimer disease: Similar to neutrophils, NK cells can also infiltrate the brain of the APP/PS1 mice causing Aβ pathology [115, 128, 129], however, neutrophils not only infiltrate the brain of three mouse models of AD (APP/PS1, 5 × FAD and 3 × Tg-AD mice) [130, 131], but also infiltrate the brains of AD patients.