Interestingly, randomized controlled trials on rodent models of AD have indicated that it is the membrane bound CX3CL1 and not its soluble form that regulate microglial phagocytosis of Aβ, as well as neuronal microtubule-associated protein tau (MAPT) phosphorylation (Lee et al., 2014), which when accumulated may result in instability of microtubules, consequent loss of effective transport of molecules and organelles, and ultimately neuronal death (KoSIK et al., 1986). Here, CX3CL1 is linked to Alzheimer disease.