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Papovavirus antigens in paraffin sections of PML brains
Abstract:
Brain tissue of 36 patients with definite PML (showing histologically the pathognomonic "PML cells") and of 12 cases with possible PML (showing patchy demyelination without PML cells) were studied for the presence of papovavirus antigens. A cross-reactive genus-specific serum and a serum raised against JCV were used in the peroxidase-antiperoxidase technique on formalin-fixed paraffin sections of autopsy brain. There was some variability in intensity of staining between the cases and between the sera. Papovavirus antigen-containing cells--mainly PML cells--were found in 35 definite and in one possible PML case. Twenty-nine of these brains reacted with anti-JCV serum. In five brains, antigen deposits were prominent in cytoplasm and processes of astrocytes in some areas of PML lesions. Giant astrocytes demonstrated viral antigens in six cases, indicating that these cells are indeed infected in PML. There was no staining of nerve cells or endothelial cells.
Insights
Papovavirus antigen was detected in most progressive multifocal leukoencephalopathy (PML) brain tissues, primarily in PML cells. This study confirms JC virus (JCV) as a key factor in PML pathogenesis.
Area of Science:
- Neuropathology
- Viral Infections
- Neuroimmunology
Background:
- Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system.
- PML is caused by the JC virus (JCV), a polyomavirus.
- The presence and distribution of viral antigens in PML brain tissue require further characterization.
Purpose of the Study:
- To investigate the presence and localization of papovavirus antigens in brain tissue from patients with definite and possible PML.
- To determine if JC virus (JCV) specific antibodies can detect the viral antigen in PML lesions.
- To identify the cell types infected by JCV in PML.
Main Methods:
- Histological examination of brain tissue from 36 definite and 12 possible PML cases.
- Peroxidase-antiperoxidase technique using genus-specific papovavirus serum and anti-JCV serum.
- Analysis of formalin-fixed paraffin-embedded autopsy brain sections.
Main Results:
- Papovavirus antigen was detected in 35 of 36 definite PML cases and 1 of 12 possible PML cases.
- JC virus (JCV) antigen was identified in 29 of the positive cases.
- Viral antigens were found mainly in PML cells, but also in astrocytes and giant astrocytes within PML lesions.
Conclusions:
- JC virus (JCV) is the predominant cause of progressive multifocal leukoencephalopathy (PML).
- PML cells and astrocytes are the primary cell types infected by JCV in PML.
- The study confirms the utility of immunoperoxidase techniques for diagnosing PML and identifying the causative virus.