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‘We shouldn’t lump all microorganisms together’

Hermelijn Smits is Professor of Host-commensal Interactions and Immune Modulation. In this role she is increasing our current understanding of the way in which microbes and parasites shape our immune system to protect us from respiratory infections and chronic inflammatory diseases. In her inaugural lecture on 3 February she will zoom in on the small invisible world of microorganisms.

For long this was an unknown world because it was invisible to humans. That changed with the microscope and other developments that showed that certain microorganisms are involved in diseases and therefore in death. That was discovered over 100 years ago. Microorganisms have been banished to the naughty step ever since. They are seen as the agents of death and disease. And although you can fight them with antibiotics, the motto is if you want to stay healthy, you should stay as far away from them as possible.

Not all microorganisms are bad

Smits wants to tell the other side of the story. In her inaugural lecture she will explain how we shouldn’t lump all microorganisms together and that not all microorganisms are bad. A whole group of them are actually good for us and keep our immune systems balanced so we don’t fall ill.

Whereas 100 years ago infectious diseases were seen as the main cause of death, that is no longer true. This is mainly thanks to antibiotics. We are now facing another epidemic, however: that of chronic inflammatory diseases such as allergies, asthma, certain forms of autoimmunity, chronic bowel diseases, cardiovascular disease and type 1 and 2 diabetes. These are diseases that if left untreated can lead to death. And that occurred in a very short period of time. The big question is why.

Hermelijn Smits

Changing environment and lifestyle

Epidemiological studies of this have been done in recent years. The common denominator is the big change in how we come into contact with microorganisms. Our changing environment and lifestyle may have something to do with this. Our immune system is stimulated and trained in a different way. Large differences have been found, for example, in asthma, allergies and certain forms of autoimmunity between the inhabitants of East and West Germany at the time of the Wall.

Related to this is Strachan’s hygiene hypothesis. Smits: ‘This is often said to mean that we are too clean nowadays and should get our hands dirty more often. I want to challenge that. There is nothing wrong with clean hands, good personal hygiene or a clean and tidy house. It’s much more nuanced. The British doctor and microbiologist Graham Rook has refined the hygiene hypothesis to shift the focus to microorganisms that matter instead of lumping all microorganisms together. He terms it the ‘old friends’ hypothesis.

Learn from microbes

These ‘old friends’ are microorganisms from the beginning of evolution when the immune system first developed and people lived as hunter-gatherers. They came into contact with microorganisms and their signals in a very different way. Now over the centuries we live our lives differently and no longer receive the same stimuli, especially not from those ‘old friends’.

In her inaugural lecture Smits asks whether with the right stimuli we can give our immune system a push in the right direction and regain our earlier resilience and resistance. Can we combine our modern lifestyle with the advantageous characteristics of microorganisms? Various researchers have already tried to do so, of course, but it has not proven easy. But Smits argues that it is possible and gives examples of how. We just need to learn much more about how microorganisms work and the impact they can have on our immune system.

Make a difference

On top of that, Smits wants to make the case for both young researchers and the medical research charities. ‘I’d like to call for more to be done to retain and support valuable young researchers within academia,’ she says. ‘These young people often leave at the point when they are not awarded that crucial first grant. And that’s a real shame. They are the cement of the research group and can help with teaching and training.’

Smits sees medical research charities as a bridge between research and its impact on society. ‘They take on a crucial role in pushing for academic findings to be used in medical practice by acting as an intermediary towards biotech or pharma companies or by jumping in where companies do not see a revenue model, such as in initiatives aimed at prevention. They can make a difference where the need in society is great. In promoting and seeking social impact, they are the mouthpiece towards patients and the general public.’ She therefore wants to emphasise how important it is to support these charities, also in these difficult times when less money is available for them.

Watch Hermelijn Smits’ inaugural lecture live from 16.00 hours on Friday 3 February.

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