MAPT and Alzheimer disease: It was also reported that the levels of Aβ1-42, total tau, p-181-tau, and p-S396-tau in neuron-derived exosomes (NDEs) from plasma were highly correlated with those in CSF and could differentiate patients with AD from those with MCI and/or controls with an accuracy of up to 96.4% (Fiandaca et al., 2015; Jia et al., 2019).