CX3CL1 is also decreased in the cerebrospinal fluid of patients with Alzheimer’s disease, and patients with mild to moderate Alzheimer’s disease have significantly higher plasma CX3CL1 levels compared to patients with the severe form of the disease (Kim et al., 2008; Perea et al., 2018b). Here, CX3CL1 is linked to early-onset autosomal dominant Alzheimer disease.