Papovavirus detection by electron microscopy in the brain of an elderly patient without overt progressive multifocal
Abstract:
Virions resembling papovavirus were demonstrated in glial cells in the brain of an aged patient without overt progressive multifocal leukoencephalopathy. The patient was not in a severely immunocompromised state. On histological examination, only a few tiny incomplete necrotic foci were found in the subcortical area. These foci were widely dispersed. Rare, swollen oligodendroglial cells and astrocytes in which papovavirus capsid protein (VP-1) was demonstrated immunohistochemically were present around the foci. The two typical types of virus particles i.e. 35 to 40 nm round particles and elongated particles, were observed in the nuclei of the swollen glial cells. The latter were in the minority. Distinct crystals were also found in the nuclei. The centre-to-centre distance of the particles in the crystals, about 40 nm, and the electron-opaque spots of the round-shaped virions and of the elongated particles, were indicative of structural subunits of papovavirus capsids. This case provides further evidence that papovavirus, possibly JC virus, may be reactivated in the brains of aged patients who are not in an immunocompromised state.
Insights
Papovavirus, possibly JC virus, was found in the brain of an aged patient not severely immunocompromised. This suggests papovavirus reactivation can occur in non-immunocompromised elderly individuals.
Area of Science:
- Neurology
- Virology
- Immunology
Background:
- Papovaviruses, including JC virus, are known to cause progressive multifocal leukoencephalopathy (PML) primarily in immunocompromised individuals.
- Reactivation of latent viruses in aging populations without severe immunosuppression is an area of ongoing research.
Observation:
- Papovavirus-like virions were identified within glial cells in the brain of an elderly patient lacking overt PML.
- Immunohistochemistry confirmed the presence of papovavirus capsid protein (VP-1) in swollen oligodendrocytes and astrocytes near rare necrotic foci.
- Electron microscopy revealed characteristic round and elongated virions, along with crystalline structures, within the nuclei of affected glial cells.
Findings:
- The morphology and crystalline arrangements of the observed virions were consistent with papovavirus capsid structure.
- The presence of virions in a patient without significant immunosuppression challenges the established understanding of papovavirus reactivation.
- JC virus is a potential candidate given its known association with neurological diseases.
Implications:
- This case suggests that papovavirus, potentially JC virus, may reactivate in the brains of non-immunocompromised elderly individuals.
- Further research is warranted to understand the mechanisms and prevalence of papovavirus reactivation in aging populations.
- Findings could inform diagnostic approaches and therapeutic strategies for neurological conditions in the elderly.
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