Some studies indicate that CX3CL1, also known as fractalkine, can partially suppress the pro-inflammatory response of microglia (Cardona et al., 2006), while other studies indicate that it can suppress phagocytosis of Aβ and partially enhance the pro-inflammatory response of microglia in transgenic AD mice (Lee et al., 2010). Here, CX3CL1 is linked to Alzheimer disease.