JC Virus

JC Virus

 

The human neurotropic polyomavirus (JCV) is the etiologic agent of progressive multifocal leukoencephalopathy (PML).

Epidemiology

  • Prevalence
    • Seroconversion is 90% by age 20
      • Establishes lifelong sub-clinical infection in immunocompetent patients
    • Presentation of PML is rare
  • Age – no age predisposition
  • Sex – M>F

Organism

  • JC virus is a nonenveloped DNA virus
  • BK virus and SV-40 are also members of this viral family
  • JC and BK were named using the initials of the first patients discovered with these diseases

Pathophysiology

  • Multiple foci of demyelination caused by lytic infection of the oligodendrocytes

Clinical Presentation

  • Progressive Multifocal Leukoencephalopathy (PML)
    • Fatal demyelinating disease of the central nervous system (CNS)
      • Progressive, fatal within 3-6 months
    • Almost exclusively in patients with severely impaired immunity
      • Considered an AIDS defining illness
    • Hemiplegia, visual disturbances and subcortical dementia
    • MRI demonstrates demyelinated lesions in the subcortical matter

Diagnosis

  • Laboratory testing
    • JC DNA, PCR testing in CSF – positive test with appropriate clinical syndrome strongly supports the diagnosis
  • Histology
    • Brain biopsy – usually diagnostic
      • May not be able to perform on debilitated patients
  • Imaging studies
    • CT/MRI – patchy or confluent hypodense lesions in the white matter

Treatment

  • No known treatment for virus
  • Treatment of underlying disease may help slow the progress
  • Disease is routinely fatal in neurologically symptomatic patients

See Also