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JC Virus, PML, and MS
You probably never heard of the John Cunningham (JC) virus before beginning treatment for multiple sclerosis (MS). That’s because the JC virus is a common - and usually harmless - infection. But in situations where a person’s immune system is compromised, the JC virus can cause a potentially fatal brain infection called progressive multifocal leukoencephalopathy (PML).
Certain disease-modifying therapies used to treat MS can increase the risk for developing PML because they suppress aspects of the immune system. Tysabri (Natalizumab) is usually considered the medication of most concern, though cases of PML have also occurred in people taking other MS treatments including Tecfidera (Dimethyl fumarate), Gilenya (Fingolimod), and Ocrevus (Ocrelizumab).
Before beginning one of these medications, you may receive a blood test to check for JC virus antibodies. Your physician may recommend a blood test every six months to monitor your JC virus antibody levels.
Receiving a positive JC virus test result can be frustrating and scary. Some MyMSTeam members are worried about switching treatments. “My JC virus levels have increased,” a member wrote. “My doctor is considering taking me off Tysabri.😭 This is the ONLY MEDICINE THAT HAS WORKED FOR ME!!!”
You may still be able to take Tysabri depending on the levels of JC virus antibodies in your blood. Higher levels of JC virus antibodies increase the risk of developing PML.
Doctors will sometimes recommend remaining on Tysabri for a specific period of time and then transitioning to another treatment. A member who tested positive for the JC virus shared: “My neurologist advised that I shouldn't be at a high risk for PML until I've been on Tysabri for two years. As of right now the plan is to keep monitoring for PML and remain on Tysabri for the two years then switch to something else.” Always consult your doctor before discontinuing a medication.
Other members decide to avoid any medication that can increase the risk of PML. “I don't think I would take Tysabri if I were positive because I would have too much anxiety about PML,” one member commented.
MyMSTeam members support each other when dealing with a positive JC virus result: “Doctors watch your numbers carefully,” a member wrote in response to a worried teammate. “They don't want it to happen any more than you do.”
“It’s incredible because there are many more options for treatment than there were even a decade ago,” a member encouraged another member concerned about switching treatments.
On MyMSTeam, the social network and online support group for those living with multiple sclerosis, members talk about a range of personal experiences and struggles. JC virus and PML are one of the most discussed topics.
Here are some conversations about JC virus and PML:
Here are some question-and-answer threads about JC virus and PML:
Can you relate? Share your thoughts about the JC virus and PML in the comments below or directly on MyMSTeam.
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