Progressive multifocal leukoencephalopathy: JC virus induced demyelination in the immune compromised host.

Progressive multifocal leukoencephalopathy (PML) is a fatal demyelinating disease of the central nervous system that predominantly affects immunocompromised individuals. The etiologic agent, JCV, is a widespread polyomavirus with a very specific target, the myelin-producing oligodendrocytes of the brain. During periods of immune suppression, the virus can be reactivated from lymphoid tissues and kidney, causing targeted myelin destruction and corresponding neurological deficits. The incidence of PML has increased in recent years, due in large part to the advent of AIDS and the growing number of immunodeficient individuals. Furthermore, previous serological studies have shown that greater than 80% of the human population has antibodies to JCV in circulation. When combined, these statistics highlight an increasing need to establish effective treatment regimens for infected individuals as well as strategies to identify those at risk for developing PML.