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Progressive multifocal leukoencephalopathy. Diagnosis by in situ hybridization with a biotinylated JC virus DNA probe
C M Hulette1, B T Downey, P C Burger
1Department of Pathology, Duke University Medical Center, Durham, NC 27710.
Abstract:
The accurate surgical pathological diagnosis of progressive multifocal leukoencephalopathy (PML) depends on the demonstration of pathognomonic histological features in cerebral biopsy tissue. The diagnosis may be difficult, however, if only small tissue fragments are submitted from the center of a demyelinating lesion. Previous studies by other authors have established that in situ hybridization with a biotinylated JC virus DNA probe can be a valuable diagnostic adjunct because it identifies the virally infected cells with great specificity and does not depend on the larger specimen, which may be necessary for a firm histological diagnosis. To confirm and extend these findings, we have used a commercially available biotinylated JC virus DNA probe to demonstrate the presence of viral DNA in formalin-fixed, paraffin-embedded tissues from four open biopsies, four needle biopsies, and two autopsies of patients with PML. With the goal of making this procedure applicable to the general surgical pathology laboratory, this method was adapted to the Histomatic Code-On slide stainer. The Histomatic is a programmable, robotic instrument with walk-away capability for hybridization histochemistry. Operation of this instrument requires the same expertise as execution of immunocytochemistry. With the advent of commercially available JC virus DNA probes and an automated system for hybridization histochemistry, this technology for diagnosis of PML may enter the routine diagnostic surgical pathology laboratory.
Insights
Diagnosing progressive multifocal leukoencephalopathy (PML) is improved by detecting JC virus DNA in small brain biopsy samples. This in situ hybridization method is adaptable for routine pathology labs.
Area of Science:
- Neuropathology
- Virology
- Molecular Diagnostics
Background:
- Accurate diagnosis of progressive multifocal leukoencephalopathy (PML) relies on identifying specific histological features in brain biopsies.
- Small tissue samples or central lesion biopsies can complicate histological diagnosis of PML.
- In situ hybridization (ISH) using JC virus DNA probes has shown promise for detecting infected cells, independent of specimen size.
Purpose of the Study:
- To confirm and extend the utility of JC virus DNA in situ hybridization for PML diagnosis.
- To adapt and validate this molecular diagnostic technique for routine surgical pathology.
Main Methods:
- Utilized a commercially available biotinylated JC virus DNA probe.
- Applied the ISH method to formalin-fixed, paraffin-embedded tissues from PML patient biopsies and autopsies.
- Adapted the protocol for use with the automated Histomatic Code-On slide stainer.
Main Results:
- Successfully demonstrated the presence of JC virus DNA in PML tissues using the biotinylated probe.
- Validated the applicability of the ISH method on various tissue sample types (open biopsy, needle biopsy, autopsy).
- Confirmed the feasibility of automating the ISH procedure using the Histomatic stainer.
Conclusions:
- JC virus DNA ISH is a valuable adjunct for diagnosing PML, especially with limited tissue.
- The adapted automated protocol makes this sensitive diagnostic technique accessible for routine surgical pathology.
- This approach enhances the specificity and efficiency of PML diagnosis in clinical settings.