Tysabri question

Good evening everyone i am on Tysabri and have had 31 infusions to date,i saw my specialist yesterday and he asked me if i was aware of a new virus which can drastically cut your chances of getting the dreaded PTL or i think thats what its called to about 1 in 200. i need to have a blood test to see if this virus is in my system and if it is i will have to stop tysabri straight away.he asked me if i wanted to carry on with my treatment or to stop taking it after what he had just told me.

I was in shock at this information as tysabri has totally changed my life,has anybody else been given this information and shall i continue using tysabri.

Thanks Simon x

This sounds like the JC virus - if you test negative for the virus, you do not have the risk of developing PML (though the JC virus can be acquired so even if you are negative you should not be lulled into a false sense of security and should be retested at intervals to be sure you are still negative). Can’t remember what the risk rate is - but it goes up after two years. The virus is not new but the test is relatively new in many centres. If Tysabri makes such a difference to you then the judgement is whether the risk (should you test positive - which of course you might not) outweighs the obvious benefits. I have always declined the test on the basis that knowing there was a definite risk (as opposed to a theoretical risk) would make no difference to me - I wanted to try Tysabri rather than wait passively for another relapse to come along. I have recently relented because I have deteriorated after nearly a year on Tysabri and may need to re-evaluate the balance.

By the way - meant to say, I do not think you have to cease treatment if you test positive - however you will probably need to be reconsented to continue ie on the basis that you are giving informed consent knowing there is a heightened risk. My centre does not require you to cease treatment if you are positive.

I believe that the risk of getting PML is highest during the third year of infusions (i.e. between the 25th and 36th infusion). You’re already half way through that so your neuro seems to have very strange timing?!

As anon has said, it’s called the JC virus. It’s a dormant virus that about 54% of people carry. Immunosuppressants like Tysabri can cause it to activate and this can cause PML (progressive multifocal leukoencephalopathy), an untreatable brain disease. There are procedures in place in the UK to stop PML if someone gets it.

The other major factor in getting PML is steroids. If you’ve never had steroids, the chances are much lower.

There are regular updated statistics on Tysabri and PML on the multiple sclerosis research blogspot. Here’s the latest one:


Karen x

My centre advised that if your JC Virus test comes back negative you change from monthly infusions to every two months rather than monthly…

A negative JC Virus test does not mean you won’t get PML it means your risk is negligible.

I wouldn’t say PML was untreatable, if it was, to me, it would mean it was fatal which it’s not but it is fatal if it goes untreated. Even if it is treated you can be left with major disability if it goes undiagnosed for too long.

I believe treatment is by plasma exchange (kinda of like a blood transfusion) this removes the Tysabri from your system. There is also research being done to eradicate the JC Virus in patients with PML.

Hi Simon,

If you do test possitive for the JC virus you don’t have to come off Tysabri I never had the test and don’t want it if I was asked to have it,

Tysabri has change my life and has so many benefits you might think I’m putting my head in the sand but I wouldn’t be coming of Tysabri and why give myself the worry of knowing I’m positive my next infusion will be my 44th and I’m over the highest risk of PML after your 35th infusion the risk begins to get lower.

They did say about having the infusion every 8 weeks instead of 4 one time but its only the last few months I can go the full 4 weeks I used to struggle the last week before my infusion I did miss an infusion and had to go 8 weeks it was a real struggle and it took 3 infusion to get me back to the level I was at before I missed one I cant begin to imagine where I’d be if I was to come of Tysabri :frowning:


I couldn’t have said it better myself I’m on my 43rd infusion I’m going for my 44th next Thursday I really don’t know if I’m JC positive or not I’ve never been offered the test I did tell them not to waste there money I wouldn’t be coming of Tysabri and I wouldn’t want the worry in the back of my mind that I am JC positive from what I see must people are If they have MS or not, I have a fairly good life at the minute and I’d like to stay that way as long as I can no matter how long or short it lasts I’m using the best weapon there is out there to fight MS and I’d like to be in the best shape I can be for when they find the cure