CCL2 and Alzheimer disease: Furthermore, there is an extravasation and accumulation of immune cells in AD brains that are mediated by the overexpression of molecules such as monocyte chemoattractant protein-1 (MCP-1), intercellular adhesion molecule 1 (ICAM-1), and integrins, promoting neuroinflammation as well as BBB damage [17,22,23,24,25,26].