Infections are a potent trigger of relapses

What can we learn from studying infections in MSers? #MSBlog #MSResearch

“The paper below may be old but it is as relevant today as it was back in 1994 when it was published. Infections, in particular viral infections, trigger relapses. You are more than twice as likely to have a relapse in the week prior  to, or the 5 weeks after, an infection. The infections in this paper were mainly symptomatic upper respiratory infections due to viruses, so the risk may be much higher if we could count so called minor or asymptomatic infections.”

“What do I mean by asymptomatic infections? We are continuously being exposed to new viruses that infect us but don’t cause symptoms. An example of this is the JC virus that causes PML in MSers on natalizumab. When we initially become infected with the JC virus it does not cause any symptoms; it simply gets into our body and stays there. In the majority of us this is fine and it is only if we become immunocompromised do we have a chance of this virus mutating and causing PML. Similarly, for the majority of us when we get infected with Epstein-Barr virus (EBV) it does not cause symptoms; only the minority of us get glandular fever or infectious mononucleosis. The same applies for the another herpes virus called CMV or cytomegalovirus; asymptomatic infection is the rule. What is interesting about the herpes viruses is that they become latent in the body and reactivate every now and  then. These reactivations of latent viruses are usually asymptomatic but are strong enough to stimulate the immune system and may trigger relapses. In fact there is some weak evidence that this may be the case.”

“When I did my PhD I studied an marke of immune activation on a daily basis in MSers over many months. I found that immune activation usually preceded the occurrence of new MRI lesions by a few weeks. Please remember that new MRI lesions are the equivalent of subclinical relapses. I therefore proposed in my thesis that latent viral reactivations may be the factor responsible for this immune activation, which then triggers MS disease activity. This is the reason why I became so interested in the viral MS hypothesis. These viral reactivations don’t have to apply to exogenous viruses only, i.e. viruses that come from outside the body, but could also apply to endogenous viruses, i.e. viruses that reside in our bodies or genome. The latter is referring to human endogenous retroviruses (HERVs). This is one of the hypotheses that is underpins the Charcot Project. Can we treat MS by reducing endogenous viral reactivation (HERVs)? Can we treat MS by preventing reactivation of latent herpes viruses, in particular EBV?”

“The observation of infections triggering relapses is not limited to viral infections, but also applies to bacterial infections, in particular urinary tract infections. This is why I am on a mission to improve the management of bladder problems in MSers with the aim of preventing or reducing bladder infections. There is some emerging evidence that MSers with recurrent bladder infections do worse than MSers without bladder infections.”

“So you can see there is still a lot we don’t know about MS. The role of infections is just one aspect we need to study in more detail. Who knows by doing this we may pin down the cause of MS? I am already a believer in EBV being the cause. I am convinced that if we can stop people becoming infected with EBV we will prevent them getting MS and that if we treat MSers with drugs that eliminate EBV from their bodies we will stop MS in its tracks. As I have said before once you have become infected with EBV it remains latent inside B cells; drugs that target B cells by transiently depleting them are the most effective drugs we have (alemtuzumab, rituximab, ocrelizumab, mitoxantrone, cladribine, bone marrow transplantation). What about natalizumab and fingolimod? Natalizumab stops B cells crossing from the blood into the brain and spinal cord and fingolimod traps B cells in lymph nodes. What all these drugs have in common is the B cell. My money is therefore on B cells and EBV as being the therapeutic target in treating MS.”

Panitch HS. Influence of infection on exacerbations of multiple sclerosis. Ann Neurol. 1994;36 Suppl:S25-8.

Background: Exacerbations of MS are triggered by exogenous events, the best documented being viral upper respiratory infections (URIs), which can stimulate secretion of cytokines such as interferon-gamma (IFN-gamma) by immune cells. 

Methods: In conjunction with a recent clinical trial of systemic interferon-beta (IFN-beta) in relapsing-remitting MS, we studied the occurrence of viral infections and their correlation with MS attacks. Thirty MSers kept daily logs, noting URI symptoms in themselves, family members, and co-workers. MSers were examined every 3 months, or whenever an attack of MS occurred, and were tested for antibodies to common upper respiratory pathogens. 

Results: A strong correlation was found between MS attacks and URIs. There were 168 URIs in 2,792 MSer-weeks, including 996 weeks at risk (the interval beginning 1 week before and ending 5 weeks after onset of URI symptoms) and 1,796 weeks not at risk. Nearly two-thirds of attacks occurred in periods at risk. Attack rates were 2.92 per year in weeks at risk compared to 1.16 per year in weeks not at risk, a significant difference (p < 0.001). High-dose interferon reduced the frequency of MS attacks, but had no effect on the number of URIs. 

Conclusions: Although a specific virus could not be incriminated, we concluded that URIs of presumed viral origin are an important trigger of MS attacks, and that treatment with IFN-beta reduces the attack rate, but not by preventing URIs. Rather, it may modulate responses to viral infection that would otherwise lead to immune activation and clinical symptoms.

About the author

Prof G

Professor of Neurology, Barts & The London. MS & Preventive Neurology thinker, blogger, runner, vegetable gardener, husband, father, cook and wine & food lover.


  • 1) So infection triggers MS attacks.
    But, 2) a relapse is defined by "the appearance of new symptoms, or the return of old symptoms, for a period of 24 hours or more – in the absence of a change in core body temperature or infection".

    How are these two statements reconciled?

    • Re: "How are these two statements reconciled?"

      The relapses tend to occur 2-3 weeks after the relapse, i.e. once the infection has resolved. In my experience the at risk period is up to 6 weeks after the infection.

  • "The paper below may be old but it is as relevant today as it was back in 1194" – I knew MS research was very slow, but King John must have been on the throne when this reearch was published!

    Please try and push things along at a slightly quicker pace.

  • A cold seems to bring on a 'relapse' of old symptoms for me. It seems to me, and my neuro took the view that but for the cold, the MS would not have relapsed of its own accord.

    On MS user boards bladder infections seem to be very common and repeatable often in the same persons.

    Increased Vitamin D level 5,000 i.u and sometimes more seem to have been beneficial since I added it about 5 years ago.

  • If viral reactivation is associated with clinical relapse there should be a rise in viral antibody titre and/or an increase in viral DNA that can be measured. Why has this seemingly simple correlation been so difficult? Or does it not exist? When latent HSV or CMV is activated these viruses can be detected.

  • If infections are related to relapses.. Can that explain why relapse frequency and EDSS progression / Brain atrophy don't seem to correlate? And why some drugs seem to have good effect on reducing replases , but no effect on brain atrophy?

  • I've worked in offices where the whole workforce has had flu or colds and I've been the only person not to become ill. I'm not exaggerating, the first time I thought it was a fluke. Has anyone else experienced this?

  • Yes same here – I can't remember the last time I had a cold/flu and I work in an office where over last couple of years loads of people had colds etc, + saw people in social situations who had pretty bad colds and I managed to escape them all. So yes, I experienced this too.

    • Are you on your big dose of vit D3? I think Ram said at one of the conferences that you were several times less likely to get colds etc. if you were vit D replete

    • I'm anon 8:17 no I wasn't on any medication at all, not even vitamins. However, I've always eaten healthily but not obsessed. It sounds crazy. There could be something in this ,do we have something in our bodies that protects us from the common cold? My colleagues were a couple of feet away from me, touched the same things. Strange eh?

    • As part of the inflammatory process the immune system produces mediators and cytokines that are anti-inflammatory that may protect you from colds. Interferon-beta for example is a anti-viral agent.

    • If infections are related to relapses.. Can that explain why relapse frequency and EDSS progression / Brain atrophy don't seem to correlate? And why some drugs seem to have good effect on reducing replases , but no effect on brain atrophy?

      Can Prof G please enlighten us?

  • I was unfortunate and in winter 2012 I had a nasty ear infection with fever. This began as BPPV vertigo caused by the infection then this triggered my first MS attack. This was a VI nerve palsy. I developed many new lesions in brain and also in C spine. More recently I had another mild ear infection and developed three new lesions. One periventricular that enhanced and two new in the pons that didn't enhance. MRI taken three weeks after infection. Also experienced at same time urine infection and alloydonia on thigh. This was super sensitivty to anything touching my thigh including clothes. I never used to have problems with my ears.

    • I developed BPPV 3 years ago. I was given medication by my ENT specialist that did nothing. It was so severe I couldn't take a teabag out of a mug, as my problem was up and down movements, not side to side. This lasted three and a half months. I mentioned the problem to my neurologist at my regular check up and he told me to come to the ward a few days later. He performed the Epley manoeuvre which lasted led than five minutes.I slept sitting up for 48 hours and I was cured. It has not returned. I know it was probably bad because of my MS, but since then I have found many people suffer from it and have been given drugs. I've mentioned this to friends that have been given drugs and they have asked for the Epley and it has worked for them. I understand this is common in the over 40s. Think how much the NHS would save using this technique.

  • My VI nerve palsy carried onto another long relapse as I was suffering from chronic anxiety, partly caused by hyperacusis (senstitivity to sound) causing lack of sleep. Servere Anxiety is one of my relapse triggers too. I got acute transverse myeltitis in my arms, sudden loss of around 60% strength. I definately think there is a link between MS and infections. I had glandular fever when I was at secondary school.

  • When I have a relapse I try and track back and think of what emotional state I was in days pervious to that or what was I doing. End of May this year I was upset about something and stressed for a few days. Four days later I had a sensory numbness relapse. Is there some kind of immune system reaction with MS and stress? May be there is a tipping point when this occurs. Some kind of secretion of hormone. Moderate stressors increase production of inflammatory cytokines which increase disease activity I understand.

  • I've had some relapses now that are triggered by infections. Two were ear infections and I have heard the pulsating in my left ear and had pressure and fullness in ears. I understand though that not everyone can hear the pulsating in the ear with an ear infection.

  • Last week I had urinary urgency and stinging when urinating. So the likely start of a UTI. I have a dipstick test kit at home and did this stright away. Showed blood in urine and protein. I phoned NHS 111 they said to phone my GP after that call it was 4pm. I phoned my GP surgery and a GP was due to call me back. I waited for the call until 7pm, no call came and I phoned 111 again to see what they could suggest. I got a call back from the hospital out of hours GP surgery and an appointment was arranged for me for 8.30pm same evening. The hospital GP did a dipstick test showed same results. I said to the GP I have MS and infections can trigger relapses. He gave me a packet of antibiotics to start straightaway. He advised me they are not strong antibiotics and I may need a stronger type if it doesn't nip it in the bud. So far it seems to have worked.

    Now I am in the know (do my own dipstick tests) I push for this. I have had nasty a pseudo-relapse before with UTI, urinary urgency, very heavy legs like sandbags around my ankles, then sore throat from 5 days in. The local GP surgery staff only offered to send off a urine sample to the lab, then the results took a week (to grow cultures and come back) and their excuse was they had to know the strain of infection so the correct antibiotics can be prescribed. I wrote a letter to the practice manager saying this wasn't good enough. I need the antibiotics very quickly if I get a UTI.

By Prof G



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