MAPT and Alzheimer disease: However, the findings related to the expression of p-tau immunoreactivity in peripheral nerves are still limited in the previous studies.5,11-13 In the spinal ganglia, no NFTs were detected in eight patients with PSP and 20 patients with AD.5 Stejskalova et al. 11 reported p-tau-immunoreactivity (AT8) in the anterior and posterior roots in the PSP cases.