CCL2 and Alzheimer disease: After adjusting for age and the Charlson comorbidity index (CCI), AD patients had higher baseline plasma MCP-1 levels compared with the MCI and control groups and severe AD patients had higher plasma MCP-1 levels compared with mild and moderate AD patients (AD vs. control, p < 0.001; AD vs. MCI, p = 0.02; CDR = 3 vs. CDR = 0.5, p = 0.01; CDR = 3 vs. CDR = 1, p = 0.002; CDR = 3 vs. CDR = 2, p = 0.007) (Tables 2 and 3).