Why's my virus lingering?

In my previous post, written while in the gloomy grip of a viral illness I was eagerly awaiting the arrival of legions of lymphocytes and antibodies, all perfectly honed to deal with this particular virus. I am now at the “lingering” phase.

Disabling lassitude and gloom receded as my innate immune system retired from the field. My energy levels are nearly recovered but my sinuses are sensitive and my nasal passages and larynx are still decidedly damp.  And everyone I speak to who has had a winter virus seems to have the same complaint – it’s gone, in the main, but not yet forgotten. “It’s lingering” seems to be the common theme.

We should nod with respect to the complex interaction that helps us move into phase two. The innate system obviously “knows” when it can let up with those darn cytokines and let the adaptive system do its work. Hence the big leap forward after 4-7 days.

But why does the miraculous and ultimately effective adaptive immune system take so long to finally get rid of coughs and catarrh?

We have to imagine a numbers game. Viruses “breed” by invading cells and using material in those cells to make a new batch of viruses. The numbers produced are very, very large. Every time an infected cell bursts open they are releasing many thousands of virus particles with the potential to infect nearby cells.

The lymphocytes and antibodies are numerous too, but as they start to do their work, the virus production line is well-established so there is a massive amount of catching up to be done. It’s a bit like weeding a large patch of land on which the weeds are already producing seeds and the seedlings are sprouting almost as fast as the gardener can work. In the end the adaptive immune system always eliminates the last few viral particles. And the bonus prize is that it remembers the unique signature of the virus, so if you encounter it again next year it will be despatched without causing a single symptom.

I have just read a long and detailed account of the interaction between the immune system and the virus during flu (see link, below). As I sit here coughing I am slightly cheered by the thought that the sticky cough-inducing mucus in my larynx is the result of the wholesale death of infected cells.

This little episode has reminded me that influenza and other flu-like illnesses do nothing to enhance life. They can wipe out a week, or three while you wait for them to go. At least when it comes to influenza itself it’s easy to reduce the chances of picking it up by having a flu jab every autumn. It won’t prevent every possible virus – but it increases your chances of having a flu-free winter, and that’s worth having.
http://bit.ly/19yZ5jr

Nature's best cold cure

It’s been years since I suffered from a “flu like illness”, years since I’ve had a cold at all in fact. But this week my luck has run out and I’m distracting myself by writing about the way the immune system reacts to viral infections.

As soon as a virus starts invading your respiratory membranes the innate division of your immune system detects the problem and swings into action. It produces chemicals known as cytokines that cause the symptoms we associate with a cold: mucus production, sneezing, stuffy nose and cough. Cytokines also affect your brain, making you feel lethargic. The body’s temperature control centre (also in the brain) may be affected, causing a  “temperature”. Inflammation is another feature of the innate immune system, hence the sore throat and pink eyes. It’s not the virus itself that causes all these effects – it’s the innate immune system reacting to it. In some viral diseases, such as pandemic flu, the immune system reaction can be so severe as to cause death.

While all this is going on and you’re struggling to carry on working, or flopped around apathetically watching daytime TV, the adaptive branch of the immune system is also working hard in the background. A swollen gland or lymph node can accompany this activity. A production line is being set up for B lymphocytes that will release antibodies against this particular virus along with a flood of uniquely-targeted T lymphocytes that will destroy the virus-infected cells. The process of getting this second-wave attack off the ground takes 4 - 7 days.

Sometimes the innate system does the trick and you “shake off the cold” quite quickly. On other occasions you just have to wait until the adaptive system is in full swing and has cleared the virus from your system.

Ibuprofen and paracetamol are helpful for relieving many of the symptoms. They are not cures however - nothing is, apart from the immune system itself.

Doctors call these viral infections “self-limiting illnesses”. Sit them out and your immune system will make you better. The body in this case is its own healer, rolling out an incredibly sophisticated dual-phase 100% successful cold cure.

In a few cases there are complications caused by bacteria which like to breed in the soggy, congested corners of the respiratory system. Babies and toddlers are more susceptible and chest infections are the most worrying. The immune system changes throughout life and as people move into their 60s and beyond they too also more likely to get a chest infection.

A bacterial chest infection that needs antibiotics is something more than just a cough. For symptoms, when to worry and other vulnerable groups see:

http://www.nhs.uk/conditions/Chest-infection-adult/Pages/Introduction.aspx 

http://www.nhs.uk/conditions/pregnancy-and-baby/pages/spotting-signs-serious-illness.aspx#close

The adaptive immune system remembers each virus it has encountered and will deal with it swiftly in future. However there are many viruses that can cause these annoying infections and because they keep mutating you will never, however long you live, be able to fend off every one.

The one I’m grappling with this week is rather persistent – but 5 days in now and I’m beginning to feel a slight lifting of the inertia that has consumed my week. I have, at least, finished writing this blog. But my patience is wearing thin, so do your stuff now, adaptive immune system, bring on those lymphocytes and bring me relief.

Norovirus - latest news

Winter vomiting (noro) virus is usually a brief, illness that lasts for a few days. For the vulnerable though diarhoea and vomiting can be more serious and if it spreads in institutional environments it can cause big problems. It transmits very easily – just a few viral particles are all that is required to infect someone.

We don’t know a great deal about why it is more common in winter or why an outbreak can appear “out of nowhere”. There is a suspicion that some individuals can carry the virus in their bodies for a long period. This happens with some other pathogens that use the faecal-oral route, such as the one that causes typhoid. In the notorious case of “Typhoid Mary” a cook passed the infection to a number of people, over a number of years.

A paper published this week has shed new light on the biology of norovirus. Researchers used a strain of mice that were infected with the virus.

One surprising discovery is that certain antibiotics, if given before infection, seem to have a protective effect against noro. This has led to the suspicion that certain gut bacteria can live in symbiotic partnership with the virus and sustain a long-term infection. This mechanism could facilitate a reservoir of infection in the community. Kill the bacteria with antibiotics and you might prevent long term noro infection.

This discovery seems unlikely to lead to antibiotic treatment for the average case of norovirus. The immune system brings about its own cure, within a few days. It’s a classic example of a self-limiting illness. Also, trying to eliminate specific bacteria in the gut is a tricky business – you can kill off friendly bacteria and leave the field clear for the much more persistent Clostridium difficile infection. Any headines suggesting a prospect of antibiotic treatment for noro are misleading.

The other discovery is that there is a specific immune chemical, a fairly recent discovery, that can attack this virus. The immune system’s armoury of chemical weapons is vast and there is still a lot to learn about how individual chemicals interact with specific pathogens. Interferons are a category that have formed the basis for drug development. As drugs they tend to be used for serious illnesses. A fairly newly discovered interferon seems to have had success in eliminating noro infection in mice.

Again this is contributing to the understanding of the virus and the detailed operation of the immune system. In the long term, dosing “carriers” of norovirus, who are not ill, with a potent interferon-based drug, is unlikely to prove to be a practical proposition.

The best defence agains noro virus is hygiene. Wash hands regularly during the winter and if anyone in the family is ill, use diluted bleach to swab down bathroom surfaces.

http://bit.ly/14CQc50

http://www.nhs.uk/conditions/Norovirus/Pages/Introduction.aspx

What is plasma treatment?

It’s reported in the press that a health care worker, recently diagnosed with Ebola, is being offered plasma treatment in a London hospital. This involves a transfusion of plasma from patients who have recovered from Ebola.

Plasma (blood with the cells removed) is a rich broth, full of antibodies and other immune proteins. The treatment should perhaps be re-named “antibody transfusion”.

When there's a new, unfamiliar infection the adaptive division of the immune system takes a while to set up a production line for the appropriate antibodies. First, a wandering immune cell detects the presence of a virus or bacterium and carries it to a lymph node where it's examined by passing lymphocytes. If a lymphocyte identifies it as a new threat it settles down in the lymph node, cloning a huge number of identical self-copies. These are then released (into the plasma) with the capacity to flood the body with millions of copies of the newly minted antibody. It is this lymphocyte-cloning process that takes several days.

The danger is, that in a disease like Ebola, a patient could die before their own antibodies can be produced in sufficient quantities to eliminate the virus. An infusion of antibodies from a recovered patient has the potential to keep them alive until their own production gets up to speed.

From the late 1890s plasma has been used to treat infections. Often the donor was a horse, which had been inoculated with a virus or bacterium causing it to form ample quantities of the antibody. The technique saved many lives but had its disadvantages – the need to keep large stables of horses and the risk of developing immune reactions to equine plasma proteins to name but two. The practice declined rapidly with the discovery of antibiotics and other modern drugs.

Plasma donated by human Ebola survivors has proved useful in previous outbreaks and is probably the best treatment currently available. As with any type of blood transfusion donors should be screened for viruses such as HIV. WHO has recently issued guidelines.

I’m sure we all hope that in this current UK case it will prove successful.

http://apps.who.int/iris/bitstream/10665/135591/1/WHO_HIS_SDS_2014.8_eng.pdf

Ebola and the immune system

I’ve often wished the immune system had a different name. One that sounded a lot more grand and complicated. It slips easily off the tongue and gulls people into thinking that it’s no more complicated than their central heating system. And that the equivalent of a tweak of the thermostat (in the form of a pill or a foot massage) can give “it” a quick boost. When researching my book I realised that it’s a system of a very different kind – more like, say, the complexity of a city like London with its workers, businesses, buildings and transport networks.

There are two main divisions to the immune system. The emergency “innate” division kicks in the minute you have a wound. On a much slower timescale the “adaptive” division learns about all the bacteria, viruses and proteins in your environment – which to ignore and which to attack with antibodies the next time they crop up. There are many different types of immune cell (“white blood cells”) and new sub-types are discovered regularly. They produce a vast array of complex proteins called cytokines that also play a role in attacking pathogens. Part of what we mean by “immune system” is this interacting mass of cells and proteins that flow through blood and tissues during health and illness. But there is more. The permanent structures of the immune system are the bone marrow, which is the production unit for replacement immune cells, and the lymphatic system that monitors threats throughout the body.

As in cities, balance is important. You don’t need a rail system that varies its timetable unpredictably. Neither do you need an immune system that is over- or under-active. Everything has to be modulated to keep things running smoothly so as to prevent not only infection but also self-damage. Diseases associated with an over-active immune system include all the auto-immune diseases, allergies and inflammatory conditions. Toxic shock, sepsis and the cytokine storm (which can occur in pandemic flu) are more sudden and much more deadly over-reactions.

Some illnesses are not just attacked by the immune system – they directly infect immune cells and interact with them in complex ways. It’s well known that the HIV retro-virus directly attacks immune cells, using them as a base and slowly undermining their work. TB, caused by a bacterium, also infects immune cells – the ones that normally engulf and destroy bacteria entering the lungs. Ebola too infects immune cells, and progresses far more swiftly than HIV or TB. It does so by using infected immune cells to spread the virus throughout the body. Ebola is also able to damp down aspects of the immune function. But that is not all. The high fever and inflammation of the later stages of the disease are part of a massive immune over-reaction that contributes to death. 

There are various scientific initiatives attempting to tackle this unusual virus but the solutions are not simple.

There are some anti-viral drugs undergoing accelerated trials but it would be surprising if they make a significant impact. The might of the pharmaceutical industry has yet to produce a range of wonder-working anti-virals for other diseases. Anti-retrovirals, used for HIV, are probably the biggest success, despite all their limitations. Vaccine development is a long and difficult road and vaccines in current development are a while away from any prospect of a  mass roll-out. The experimental biological treatment ZMapp is a product of immunological research. It’s a combination of artificially produced antibodies that lock on to specific targets on the Ebola virus, disabling it. It is to be hoped that ZMapp works, and that one day it can be produced in large enough quantities to be useful in bringing outbreaks under control. However production methods are complex involving a lot of careful work by technicians and the growth of cloned cells in laboratory conditions. This process is not at all like the factory production line that produces conventional chemical drugs. My feeling is that science is very unlikely to come up with any quick answers, with mass impact, in the next few months.

In the meantime though, simple nursing measures like infection control and putting up a drip can save lives. As Christmas looms we are asked to contribute to a wide range of charities but this year many of us will perhaps consider that paying for some nursing supplies for Ebola stricken areas is the most urgent call on our generosity.

http://www.bbc.co.uk/news/health-30217573

"Immune Boosting" Alcohol?

Everyone wants to promote the idea of “boosting the immune system” these days. Those who sell supplements lead the charge, with a regiment of alternative practitioners following closely behind. Immune boosting is also a favourite phrase with journalists, It’s a cheap and easy way of writing headlines. Scientists and science journalists succumb to its lure as well. This reported experiment with Barbary apes and alcohol is a good example.

Eight monkeys were allowed free access to alcoholic drinks for 7 months. Four of them were deemed heavy drinkers and the other four, moderate drinkers, depending on their freely chosen intake. There was a comparison group that was allowed no alcohol. The monkeys’ response to smallpox vaccine was tracked. It is not surprising that the heavy drinkers showed impaired immune function. Alcohol is toxic and large amounts of it will damage just about any bodily function you care to name.

What was more interesting is that the moderate drinkers had a better response to the vaccine than either of the other groups. We should, though, be skeptical about the size of the groups and the fact that the comparison groups were self-selecting rather than randomly allocated. Maybe the immune systems of those drawn to heavy drinking were different in some way to the more temperate beasts. We should also, always, be skeptical about making direct inferences from animal studies to human health.

For scientists, or science journalists, to talk about “boosting the immune system” is a bit like the mayor saying that some free-to-use bikes will boost the economy of the city, just because a few more energy drinks were sold in a few local kiosks. Like a city, the immune system is an immensely complex and intricate set of interlocking sub-systems. Millions upon millions of immune cells interact with billions of immune molecules to keep a body in a finely-balanced state of health. There are many different types of these cells and molecules - they are incredibly small and incredibly numerous. Strength of response to a single vaccine does not tell us anything about how the same immune system might cope with other vaccines, with TB, MRSA or the common cold. You cannot “boost” the whole thing – it’s a crazy concept. And we should never forget that an over-active immune system can be just as harmful as an under-active one – in allergies and the many auto-immune diseases for instance.

It’s New Year’s Eve – if you drink heavily you might be more likely to get an infection of some kind in the next few days. But if you exercise restraint and only have a glass or two, there are no promises that this will serve to actively improve your health. But drunk or sober, I hope you have a happy and healthy 2014.

Moderate Alcohol Consumption Boosts Body's Immune System

'Flu update

It's that time of year again. Doctors are planning their 'flu vaccine clinics and posters are appearing reminding us to get our annual dose. Since last year there have been several interesting new developments in ‘flu research.

Over a hundred cases of H7N9 'flu in humans, probably contracted from poultry, have been seen in China. The high death rate emphasises the importance of influenza research. It's a race against time before a variant emerges that can easily be transmitted between humans. When it does it could cause a lethal pandemic with catastrophic death rates.

Even the usual winter 'flu sometimes causes serious illness and up to half a million people die of it, every year.

Some of this year's new information is based on analysis of existing data.

A systematic review of a large number of studies highlighted that new mums (but not pregnant ones) and obese individuals seem to be at an increased risk of dying of the complications of 'flu. These two risk groups have not been previously identified. Good quality research in this area is rather thin and more is needed so vaccination programmes can be targeted appropriately.

Another analysis found that in the 2009 outbreak of swine 'flu, pregnant women who had been vaccinated were less likely to go into premature labour than the non-vaccinated. It seems then that 'flu vaccines during pregnancy may protect both babies, from the dangers of being born too soon and mums from becoming seriously ill with 'flu, or even dying, in the month following delivery.

An Australian study looked at links between heart attacks and 'flu, using data on middle-aged people admitted to hospital. It found that having a 'flu vaccination seemed to have a protective effect against heart attacks. If other research confirmed this result it would, again, lead to a change in the recommendations for priority groups.

One of the most interesting, and surprising, findings of the year is that 'flu vaccines are not as specific as everyone thought. Immunology theory is clear - that the immune system develops antibodies, one virus at a time. So every variant of the virus requires a vaccine to match it. Each year the vaccine is a cocktail of the three types that are currently most common worldwide. This new study found that the vaccine gives significant protection against types of 'flu that are not included as well as those that are. This highlights the fact that there is a lot more to the immune system than just antibodies - and that there is still a great deal to learn about how it works.

Finally, for the needle-shy, there is hope on the horizon. Nasal spray 'flu vaccines are being introduced, (initially for use with children in the UK) and research on mice has revealed that a micro-needle patch can deliver 'flu vaccine effectively. I imagine this would be a bit like pressing a bit of Velcro or sandpaper against your skin.

In the UK the 'flu vaccine is free to priority groups and the rest of us have to pay. I always think that £10 spent on a 'flu jab is fantastically good value if it means I can get through another winter without a bout of this debilitating illness.

New risk groups

http://bit.ly/15ZLtuK

Vaccine in pregnancy

http://bit.ly/14PbZpK

Heart attacks

http://bit.ly/19e7dz6

Wider protection

http://bit.ly/158W4my

Micro patches

http://bit.ly/1geayRr