CCL2 and Alzheimer disease: In contrast to the lack of significance in serum/plasma, it was observed that the CSF levels of CCL2 were higher in AD than in controls (RoM, 1.19, 95% CI, 1.13–1.25, corrected p < 0.001; I2 = 0), and in MCI than HC (RoM, 1.16, 95% CI, 1.05–1.29, corrected p = 0.012; I2 = 59.2%).