CCL22 and Alzheimer disease: The median serum CXCL-12, CCL-17, and CCL-22 levels were significantly higher in AD patients from Group 2 than in the age-matched Control 2 (2553.5 pg/mL versus 2361.1 pg/mL, P = .01; 357.6 pg/mL versus 178.3 pg/mL, P = .04; 1152.5 pg/mL versus 606.1 pg/mL, P = .001; resp).