CCL2 and Alzheimer disease: Clinical data of AD patients have shown an increase of CCL2 both in CSF and in plasma (Westin et al., 2012; Zhang et al., 2013), and, according to several authors, it correlates with the disease progression and the cognitive decline (Galimberti et al., 2006a; Kimura et al., 2018; Lee et al., 2018).