Tag: Jcv

Tysabri (natalizumab) carries a U.S. Food and Drug Administration (FDA) boxed warning due to the increased risk of progressive multifocal leukoencephalopathy (PML). This rare but serious brain infection is a primary concern for patients, making it critical to understand **who should not take Tysabri** to ensure safety and effectiveness.

Many people carry the John Cunningham (JC) virus, which, in those with weakened immune systems, can lead to a rare but serious brain infection called Progressive Multifocal Leukoencephalopathy (PML). For individuals with multiple sclerosis (MS) who test positive for the virus, a key question is whether they can take Kesimpta if they are JCV positive.

Progressive multifocal leukoencephalopathy (PML) is a devastating and rare viral brain infection that occurs almost exclusively in severely immunosuppressed individuals. Certain biologic medications can significantly increase the risk of this condition by altering immune function, making it crucial for patients and providers to understand **which biologics cause PML** and the associated risk factors.