What makes some go from JCV- to JCV+

[rathsog]

I have been on Rebif for the last 5 years and somewhere in the last 15 months, developed another lesion. Since I truly hate the Rebif and the loathsome side effects, my neuro is suggesting I switch to either Tysabri, Gilenya, or Tec.

I had the JC virus blood test and am negative. What would make me become JC virus positive? Is there something I can control that can make it possible never to have this crossover from negative to positive? Trying to make as informed a choice as possible so any and all input is welcome.

Thank you!

[Kimba22]

Hi rathsog,

Exposure to the JC Virus, which can happen at any time, is what would cause you to become positive. Here's a few links for you:
http://www.healthline.com/health/mul...toctest=expand
https://www.msworld.org/forum/showthread.php?t=122112

There is also now a JCV antibody titer test that measures the amount of JCV antibodies present if you ever did become JCV +, which determines the PML risk factor (the higher the number, the higher the risk for developing PML). http://www.medscape.com/viewarticle/806294

Other factors that increase the risk for developing PML are the number of infusions one has had, and prior immunosuppressant use. Here's a chart for you: http://www.slideshare.net/gavingiova...hare_slideshow

Here is also a link to the National MS Society about Tysabri: http://www.nationalmssociety.org/abo...mab/index.aspx

I hope this info helps you to make an informed choice! I hope you'll let us know what you decide.

Good luck,

[ru4cats]

I don't know if this information is in the links Kimba provided, but I just saw my neurologist, and she said 2% seroconvert from - to + each year (2/100). I have had 5 blood tests and am still negative.