neurologic disorders
Progressive Multifocal Leukoencephalopathy (PML)
Etiology of PML
Progressive multifocal leukoencephalopathy is caused by reactivation of the JC virus, a ubiquitous human papovavirus that is typically acquired during childhood and remains latent in the kidneys and possibly other sites (eg, mononuclear cells, central nervous system [CNS]). The reactivated virus has a tropism for oligodendrocytes. Most patients who develop PML have depressed cell-mediated immunity due to Immune system (the most common risk factor) Reticuloendothelial system disorders (eg, Overview of Leukemia , Other conditions (eg, Wiskott-Aldrich Syndrome , The risk in AIDS increases with increasing HIV viral load; prevalence of PML has decreased because of widespread use of more effective antiretrovirals. Increasingly, PML is occurring as a complication of immunomodulatory therapy. The drugs most frequently implicated include The monoclonal antibodynatalizumab The antibody-drug conjugatebrentuximab vedotin But PML has occurred in patients taking other drugs (eg,rituximab,fingolimod,dimethyl fumarate). Measuring serum antibodies to JC virus (JC virus index) may help assess the risk of PML in patients takingnatalizumab; higher levels indicate higher risk. 