Neurofibrillary tangles in the neurons of spinal dorsal root ganglia of patients with progressive supranuclear palsy.

Neurofibrillary tangles (NFTs) occur in neurons of human central nervous system (CNS) both in aged subjects and patients with several degenerative diseases, with a certain topographical predilection. In surveying the NFT distribution in nervous tissue of patients with progressive supranuclear palsy (PSP), we found silver-positive fibrillary tangles in the neurons of dorsal root ganglia (DRG) in two of five patients. By immunohistochemistry, these tangles were stained with antibodies to human tau protein, paired helical filaments (PHFs) and ubiquitin. Electron microscopy revealed that they were mainly composed of PHFs that were morphologically indistinguishable from PHFs in the NFTs of CNS typically seen in Alzheimer's disease brains. Our data demonstrate for the first time that the neurons of DRG produce NFTs in PSP and suggest that the pathological process(es) leading to tangle formation can occur in the neurons of the peripheral nervous system in this disease condition.