Cerebellar basket cells of Creutzfeldt-Jakob disease: immunohistochemical and ultrastructural study.

To elucidate possible abnormalities of cerebellar basket cells of Creutzfeldt-Jakob disease (CJD), seven sporadic cases were examined neuropathologically. Recently, parvalbumin-positive, GABAergic cerebral interneurons have been demonstrated to show early, selective loss in CJD, and the phenomenon is postulated as a cause of characteristic neurological symptoms of CJD. In this study, however, we demonstrated that the basket cells, cerebellar counterparts, were resistant even in patients with severe brain atrophy, and their processes showed intense argyrophilia and immunopositivity to phosphorylated neurofilament. They can newly be listed as CJD-resistant neurons similar to those of the hippocampus and brainstem nuclei. The mechanism to escape cell loss is of great interest, and there might be unknown factors modulating susceptibility within parvalbumin-positive neuronal subgroups. Furthermore, one case showed abnormal positivity with hematoxylin, crystal violet and pyronin in the basket cells. The pyronin positivity was reduced after ribonuclease digestion, suggesting that the causative substance was composed of RNA. Ultrastructurally, the fibers contained free ribosomes and amorphous electron-dense deposits. To our knowledge, such a finding has also not been previously reported.