A biomarker panel of cortisol, pancreatic polypeptide, insulin-like growth factor binding protein 2, β2-microglobulin, vascular cell adhesion molecule 1, carcinoembryonic antigen, matrix metalloproteinase 2, CD40, macrophage inflammatory protein 1α, superoxide dismutase, and homocysteine was shown to significantly increase in plasma from patients with AD. Here, CD40 is linked to Alzheimer disease.