Although we speculate that tau movement from the brain to the blood circulation has the potential to stimulate the production of PAbs against tau (PAbs‐tau),113 most studies have investigated NAbs to tau (NAbs‐tau) in plasma, and whether they are altered in AD patients, by using immunofluorescence staining, Western blot assays, and ELISA108, 111, 112, 121 (Table 4). The gene discussed is MAPT; the disease is Alzheimer disease.