Tysabri - JC Positive - Is it worth the risk??


I have RRMS and I’m suffering with an almighty relapse at the moment affecting the mobility of my hand and arm quite considerably. I’ve had another MRI confirming new lesions and my neuro has discussed with me moving on to taking tysabri.

I tested positive for JC but i’m still being strongly advised to go ahead - being told the risks are low for the first 2 years.

I’m just a bit worried about the possibility of PML - which sounds horrendous.

Would really appreciate some advice from someone in similar circs?

Thanks in advance

No personal experience of tysabri, but this is the clearest explanation of risk I have seen.

Hi, I’m not JC positive but I do understand that it’s not an easy decision, when you considering a drug that has some serious side affects - PML being the one most talked about. I had many sleepless nights and arguments with my husband (he thought I should take it) before making a decision to start this treatment. I met and spoke with many others who were taking Tysabri and there was a mix of JC Virus positive & negative people. It was interesting in hearing their personal stories & what led them in making their decision. There were two who had been offered this drug before but declined because of their concerns about PML, but 12-18 months later their condition progressed and it was at this point that they decided the risks were worth taking. They both regret not taking it sooner as their level of disability when offered Tysabri the first time around could have possibly been maintained. My neurologist is of the same mind, he said your next relapse could be a major one and wouldn’t want the fall out of this being my starting point. My last 2 relapses have affected my arms & while I can manage when my legs are not working so well, I can’t cope without the use of my arms. I know I could become JC positive while on this drug and also aware that being immunosuppressed I am at risk of infection (which I have right now), but if this can slow down the progression, reduce my relapses & maintain my current level of disability, then yes it is a risk worth taking. I don’t always feel like this and do get the wobbles, but this is just human nature. Hope you make your decision soon. There is a Tysabri blog www.msrc.co.uk/index.cfm/.../269 where you will find many personal stories. Taz Sent from my iPhone


My understanding was that most people are JC positive. I am,and have been on it for over 2 years. The hospital seem pretty clued up about monitoring for PML though. Every time I have an infusion, they ask a quick questionnaire. If there any changes in symptoms then they arrange for an MRI scan to check everything’s OK.

I understand your concerns though. I guess the decision comes downto you though. I’ve obviously decided to carry on, but there may comea time in the future when I decide to stop, or have a break. You could always ask your neuro though if there are any alternatives you could consider.



I am JC+ and on Tysabri - and it really is personal choice. I actually did not know I was positive until my third infusion of Tysabri. My MS was really very active and I had been on Rebif which was not working for me. I weighed up the pros and cons of eveything and in the end i decided that I wanted to go with the most aggressive form of treatment that I could. The risks of PML are very small but still it is a worry, but the nurses keep a really really close eye on you and you can also inform family of things to look out for.

Now I am on Tysabri - the benefits of it are way out weighing the negatives, I always knew that regardless of my results (positive or otherwise) I would take the treatment.

If you have any questions please feel free to PM me I dont know all the answers but I have personal experience - I think I am on infusion number 8 now…

Good Luck


I am sorry you are being invited to join the club no one wants to be in.

At least you have a clear steer from your neurologist and know exactly what he/she thinks is best for you, given your circumstances and the way your MS is behaving. It was the same for me. I started Tysabri before the JC test was available in this area, so I do not have experience of the exact situation you are in, but the principle was the same - weighing up a small but very serious theoretical risk (PML) against the clear and present danger of active MS continuing to take lumps out of me.

One thing’s for sure - there are no right answers to the question: no risk-free option is available. I think all a person can do is to make as well-informed a decision as they can and not get too tangled up with trying to find the ‘right’ answer. There isn’t one. At the end of the day, you take a punt, one way or the other. My personal approach is to take the neurologist’s advice unless I have a better idea, but it is a personal decision.

Good luck with whatever you decide.



I have been on Tysabri now for over 3 years. I told my MS neuro and infusion nurses not to bohter with the JCV test as I told 'em that Iwon’t be coming off it even if I am positive as the PML risk has been far outweighed bby the benefits of this treatment. To put it succinctly: don’t know and don’t care.


Hello there.

I started Tysabri 3 years ago…im JC positive … but I dont dwell on what ‘might’ happen. I tend to just get on with it. Im still working (part-time) still run a home, look after 2 teenage boys and am also married to a ‘Pleb’.

Am I worried about the JC Virus ? Hell no.

Go for it.

I’m on Tysabri over 4 years now I didn’t know or didn’t want to know if I was JC+ or JC- there was no test when I started Tysabri my MS was that bad relapsing every 4 or 5 weeks it got to the stage I ended up in a wheelchair and could only use my left hand I’d no control over bladder or bowels and fatigue was really really bad.

I told my neuro I would try anything no matter want the risks so he send me for an Mri in June 2008 and I started Tysabri in August 2008.

I found out I was JC- in June this year I didn’t want the test but my neuro said they’d like to know I said to my neuro I’ll have it done but I don’t want to know the results I had It done on March this year I thought it was kind of pointless as anyone that knows will tell you even though your JC- it could change to JC+ over night and you may even be better JC+ cause they would keep a closer eye on things.

Its easy for me I know and feel the benefits Tysabri have giving me I haven’t relapsed since I started Tysabri I’m out off a weelchair walking I even go to the gym and work out know a few times a week the only problems I have now is I have to use a catheter and the week before my infusion sometimes my right ankle gets a little weak. And all the Mri’s I have done show the damage getting worse from when I was diagnosed till I started Tysabri but even the first year on Tysabri they showed my MS was stable and improving from the one I had done when I was at my worst just before I started Tysabri to my last there in June last year the difference is amazing not only can I feel its working its there in black and white to prove it :slight_smile:

So for me there’s no risk that high when I went from the way I was to the way I am now. I have an Mri every year but if your JC+ they do them every 6 months and leave nothing to chance.