We found that the levels of CCL5 (SMD = 2.56, 95% CI: 1.91–3.21) and CCL15 (SMD = 3.30, 95% CI: 1.48–5.13) in the plasma of AD patients were higher than those of healthy people, while the levels of MIP-1β (SMD = 0.32, 95% CI: −0.50 to 0.57) and SDF-1α (SMD = 0.03, 95% CI: −1.56 to 1.62) showed no significant difference (Table 2). This evidence concerns the gene CXCL12 and Alzheimer disease.