Just started my first infusion… Tysabrisi… Went well and no issues… woke sat and had big itchy hive on my neck… only one, presume maybe a reaction as this is new to me… any chance anyone knows if safe to take antihistamine… ie piriteze… or recommendations??

Hello Teri

I think you should try speaking to your Tysabri infusion nurse. As far as I knew, allergic reactions to Tysabri aren’t usual on the first infusion, but are possible on the second or later.

Don’t just try to fix it with antihistamines.

Best of luck. I do hope it gets better soon.


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My sister is now on Tysabri after suffering an awful relapse back last year.

She has an MRI scan every 6 months, and so far theres no new lesions.

Sadly though, this particular relapse has left her with some devastating lasting damage.

We went to a family funeral yesterday, (my sister couldn’t attend), and I was talking to my brother in law about my sister and her treatment, in particular Tysabri, he told me that when she had this relapse last year her consultant offered her Tysabri but explained that theres one particular risk involved when taking this drug.

Apparently we all (everybody) has a certain very nasty virus within our bodies that usually just stays there dormant not causing any issues, but sometimes people on Tysabri run the risk of this virus being “woken up” by the drug, which can then be a very nasty illness.

I’ve never heard of this or know the name of the virus, but apparently the MS consultant was very clear in warning my sister of this risk when taking Tysabri.

I might be wrong but I think my brother in law said it was a virus that sat dormant in the brain with every one, not just us with MS, but if woken up it can be very very nasty.

Like I say I’ve not really heard anything about this apart from what my brother in law explained, so it might be worth asking your consultant about it ?

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This is now quite well known. Tysabri could theoretically cause a virus called progressive multifocal leukoencephalopathy or PML. It is a very serious neurological viral disease and can cause severe disability or even death.

But, it can only be activated by a person who has antibodies for the John Cunningham Virus (JCV) in their system. Many people do test positive for JCV, although there are degrees of likelihood as to whether a person could get PML even though the individual is JCV positive. Everyone who starts taking Tysabri is tested for JCV status before starting the drug and then, if positive, given the option not to take it.

Plus, PML has never been detected in someone who has been given Tysabri for less than 2 years. So even were a person to be JCV+, they won’t get PML if they’ve been on Tysabri for less than 2 years. After that point, their chances of getting PML are weighted according to their JCV status.

Not everyone tested for JCV tests positive (I didn’t), but the JC virus is silent, so you wouldn’t know that you’d come into contact with it. You could even develop the antibodies to it (ie become JCV+) whilst on Tysabri. For this reason, everyone is retested every year.

So while your sister takes Tysabri, she’s not currently at risk of PML. After 2 years on Tysabri, if she’s JCV+ then she’ll have her chances of PML rated and will have the option of coming off Tysabri and starting a different DMD or staying on it.


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Thats it Ssssue spot on.

I’m almost sure my brother in law said that my sister did actually test positive for the JCV ?

But due to the severity of the relapse I think she took the attitude nothing ventured nothing gained !

Another relapse of that magnitude, wouldn’t be worth thinking about, so my understanding is she’s hoping the Tysabri will protect from another relapse and this virus thing will behave itself !

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I just started having a look for a reputable source on JCV and PML and found this: looks quite interesting.


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Thats a great link Ssssue, thanks.

Its a lot to accept and take on board if you are considering taking Tysabri !

But then again, after seeing what 1 bad relapse did to my sister I think I would seriously consider taking it if I were still RR.

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thanks all…my ‘reaction’,turned out to be nothing more than a bug bite…all cleared…have been tested for the JVC and cleared …but like you say it can be ‘awakened’, if you get colds or flu like bugs…but so far (and i have had my second dose) everything is ok…nurse said they will be taking bloods with each ‘monthly’ infusion to keep an eye on liver as well as other things so just got to go with the flow…

When I first started Tysabri back in August 2008 I got an antihistamine injection before every infusion that went on for a year or so.

My last infusion was my 143rd, I’m JC positive but that doesn’t bother me It dosen’t even cross my mind. I’ve been relapse free since startin Tysabri and able to get out of my wheelchair and learnt to walk again after mt 3rd infusion.

Before tysabri I was relapsing every 4 or 5 weeks which left me in a wheelchair with only the use of my left arm, that was only the things people could see wrong with me.

So for me the benefits far outweigh any risks there maybe, about 4 years ago my risk of PML was 1/80, I haven’t a clue what it is now cause the charts don’t go any higher than 7 years (I’m on my 11th). I will always put quauity of life over quantity.