Progressive multifocal leucoencephalopathy: detection of papovavirus JC in kidney tissue

Area of Science:

• Nephrology
• Virology
• Molecular Biology

Background:

• Progressive multifocal leukoencephalopathy (PML) is a rare, demyelinating disease of the central nervous system.
• JC virus (JCV) is the causative agent of PML, and its presence in other organs, such as the kidney, is of clinical interest.

Purpose of the Study:

• To investigate the presence and localization of JC virus DNA in the kidney of a patient with PML.
• To differentiate JCV from the related BK virus (BKV) and determine the state of viral DNA (integrated vs. free).

Main Methods:

• Reassociation kinetics to detect viral DNA sequences.
• Restriction enzyme cleavage (Hind II, XHO I, Eco RI, BAM HI) and Southern blot analysis for viral DNA characterization.
• In situ hybridization to identify infected cell types.

Main Results:

• JC virus DNA was detected in various kidney areas, with the highest concentration in the renal medulla (175 genome equivalents/cell) and minimal presence in the renal cortex.
• Restriction enzyme analysis confirmed the presence of JCV and differentiated it from BKV.
• Analysis indicated that the viral DNA was free and not integrated into the host genome.
• In situ hybridization identified epithelial cells lining the collecting tubules as the predominant site of JCV infection in the kidney.

Conclusions:

• The kidney, particularly the renal medulla and collecting tubules, harbors JC virus DNA in patients with PML.
• The findings suggest that the kidney could be a reservoir for JCV, with free viral DNA present in infected epithelial cells.