MAPT and Alzheimer disease: Because earlier studies have shown that aluminum exposure is linked to Alzheimer’s disease etiology, and high aluminum content is detected in Alzheimer’s patients’ brain tissue, we also measured aluminum antibody in the blood of patients with Alzheimer’s disease who are positive for amyloid-β-peptide (Aβ-peptide) and phosphorylated tau antibodies and had reversed ratio between amyloid-β-40 versus amyloid-β-42 peptides.