They serve to maintain microglial homeostasis through the balance of noninflammatory cytokines, i.e., Interleukin 10 (IL-10, Interleukin 13 (IL-13), and proinflammatory cytokines such as Interleukin 6 (Il-6), tumor necrosis factor-alpha (TNF-α), and Interleukin 1 beta (IL-1β), which are significantly expressed in AD. Here, TNF is linked to Alzheimer disease.