Comparing serum median levels of analyzed chemokines between two AD groups (Group 1 versus Group 2) the only significant difference was found for CCL-20 which median value was higher in children below 10 years old than in older population (Group 2) (7.8 pg/mL versus 7.4 pg/mL; P = .03). The gene discussed is CCL20; the disease is Alzheimer disease.