JC Virus

Shmuel Shoham, M.D., Paul Auwaerter, M.D.


  • JC virus (JCV) is a DNA polyomavirus discovered in 1971, isolated from patient John Cunningham.
    • Other polyomaviruses:
      • JCV is genetically closely related to BK and SV40 viruses.
      • Other members of the human polyomavirus group include:
        • Trichodysplasia spinulosa virus: associated with skin disease
        • Merkel cell polyomavirus: associated with a rare form of skin cancer called Merkle cell cancer
        • KI, WU, MW, human polyoma 6, 7, and 9 viruses: Found in human specimen, but no clear disease associations
    • Oncogenic potential:
      • Members of this DNA tumor virus family are well-known to cause tumors in rodents; however, except for Merkle cell cancer, oncologic potential in humans less certain.
      • Some studies have linked the virus to human colorectal cancer, but this concept remains controversial.
    • Structure and composition: All polyomaviruses (including JCV) are non-enveloped and contain double-stranded DNA
    • 3 stage model of pathogenesis:
      • Stage 1: Nonpathogenic virus establishes latent infection (generally in the kidney, but also other sites such as tonsils and immune cells ): Virus may gain access to CNS at this stage.
      • Stage 2: Viral reactivation and accumulation of genetic alterations leading to the emergence of neurotropic variants: Virus may gain access to CNS at this stage.
      • Stage 3: Progressive multifocal leukoencephalopathy (PML) with rapid viral replication in oligodendrocytes with resultant demyelinating disease.

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Last updated: July 4, 2021