The results showed that levels of chitinase-3-like protein 1 (YKL-40), ICAM-1, VCAM-1, IL-15, and Flt-1 were increased in AD during the preclinical and prodromal stages, particularly in CSF tau and Ab-positive individuals, with especially high levels of YKL-40 showing the strongest association in Ab-positive individuals. This evidence concerns the gene IL15 and Alzheimer disease.