Looking for information on JC Virus and MS

[alabama954]

My friend just had to take blood test for the JC virus and can't find any information on it pertaining to MS any help??

[22cyclist]

The JC virus is the John Cunningham virus. It causes PML (an often fatal brain disease that presents like MS but is much worse) in the case of immunodeficiency. This can be from AIDS, or from certain medications used to treat autoimmune diseases, MS being one of them. The drug we are talking about in MS is Tysabri, and to a lesser extent they are looking at Tecfidera. So everyone who is starting Tysabri and Tec must be tested for JCV.

In Tysabri patients, they are tested around every 3-6 months depending on their index (number that corresponds with their risk for developing PML).

Other drugs that carry a PML warning with JCV + people are:
rituximab; efalizumab; brentuximab vedotin.

The JCV is very common among the general population, anywhere from 70-90% of people are positive. It is often acquired in childhood and can live on in the upper respiratory tract or the GI tract.

If you test positive for JCV, the index of how positive you test will help determine how good of a candidate you are for the drugs like the ones noted above.

There is a whole other side to this risk factor too that tells the risk factor by how long you have been on the drug itself. Since that is not what you asked, I will not go into that. Anyway, for now that applies mostly to Tysabri. If your friend is not going on Tysabri, no point in going into it. If she is, you can find it under the Tysabri board. There is a lot more there about indexes too.

Take care
Lisa
Moderation Team