Pathological tau proteins in postencephalitic parkinsonism: comparison with Alzheimer's disease and other neurodegenerative disorders.

Immunohistochemical and biochemical analyses of hyperphosphorylated tau proteins, the major component of neurofibrillary tangles, were performed in different brain regions from patients presenting with postencephalitic parkinsonism. Neurofibrillary tangles were found in hippocampus, neocortical areas (mostly in supragranular layers), and several subcortical structures. By immunoblotting, a tau protein triplet similar to the one seen in Alzheimer's disease was observed. This biochemical approach allows for the definition of postencephalitic parkinsonism from certain neurodegenerative disorders such as progressive supranuclear palsy and corticobasal degeneration.