CX3CL1 and Alzheimer disease: CX3C chemokine ligand 1 (CX3CL1, also named fractalkine) plays an important role in reducing neuroinflammation and is highly expressed in the main area of pathological changes in AD, such as the hippocampus and cerebral cortex, and the expression level of CX3CL1 reflects the progression of the disease [9].