Regarding innate immunity, abnormalities in the function of natural killer (NK) cells (31, 32), a decreased phagocytosis of Aβ in peripheral macrophages (19), and an altered release of pro-inflammatory cytokines [e.g. interleukin-(IL)-6, tumor necrosis factor (TNF)-α, etc.] (8) have been shown in AD patients in relation to age-matched controls. Here, TNF is linked to Alzheimer disease.