John Cunningham virus: an overview on biology and disease of the etiological agent of the progressive multifocal leukoencephalopathy.
John Cunningham virus (JCV), the etiological agent of progressive multifocal leukoencephalopathy
(PML), is the first human polyomavirus described. After asymptomatic primary infection which occurs in
childhood, the virus spreads by the hematogenous route from the primary site of infection to secondary
sites including kidneys, lymphoid tissues, peripheral blood leukocytes, and brain to establish latent infection.
During immunosuppression the virus undergoes molecular rearrangements that allow it to replicate
in glial tissues causing PML.