In addition, participants with AD showed changes in the profiles of circulating cytokines and chemokines, namely, increased levels of MDC/CCL22, IL-1ra, IL-12p70, IL-5, IL-8, IL-13, MIP-1α/CCL3, IFN-α2, Flt3L (fms-related tyrosine kinase 3 ligand), G-CSF (granulocyte colony-stimulating factor), TGF-α (transforming growth factor alpha), IFN-γ, TNF-α, and VEGF and reduced levels of IL-2, IL-1α, IL-15, and IL-17A. Here, IL15 is linked to Alzheimer disease.