CCL2 and Alzheimer disease: Our meta-analysis showed that MCP-1 protein level (SMD = 0.39, 95% CI: −0.14 to 0.93), IL-8 protein level (SMD = 0.04, 95% CI: −0.59 to 0.66) and MIP-1α protein level (SMD = 1.82, 95% CI: −0.31 to 3.96) were not significantly different in blood samples between AD patients and healthy individuals (Figures 2A–C, respectively).