It looks like you are using an older version of Internet Explorer which is not supported. We advise that you update your browser to the latest version of Microsoft Edge, or consider using other browsers such as Chrome, Firefox or Safari.

Progressive Multifocal Leukoencephalopathy (PML)

A rare viral disease of the brain.

Progressive Multifocal Leukoencephalopathy (PML) is a rare viral disease of the brain. Breaking down the term gives you a clear picture of the condition: it involves progressive damage (pathy) or inflammation (leuko) of the white matter of the brain (encephalo) at multiple locations (multifocal). Some MS medications can put you at greater risk of developing PML because they reduce the body’s ability to fight the virus.

MS Trust. JC virus and PML. Available at: Accessed April 2020

UK | July 2020 | MUL20-C021