Respiratory infections Why some children are much more susceptible to severe colds

Gene mutation: That's why some children are more prone to severe colds
A cold usually goes without major problems and usually heals within a few days, when you rest and use the right remedies. In some children, however, such viral diseases are so severe that a hospital stay is necessary. Researchers have now discovered why this is so.

Colds are usually harmless
Cold, cough, headache: A flu infection, the "simple" cold, you can catch several times a year. The symptoms start slowly and fade away after a few days. Even with most children - who generally show a greater susceptibility to infections - usually colds are harmless. For a small part of those affected, however, not. Researchers have now discovered why this is so.

A cold is usually harmless. Some children, however, have such serious viral infections that they need to be treated in the hospital. The fault is a gene mutation. (Image: Kaspars Grinvalds / fotolia.com)

Some viral infections in children must be treated in the hospital
Non-flu colds are generally harmless. However, viral infections require hospitalization for two percent of children of each generation, according to a statement by the Swiss National Science Foundation (SNSF).

"Twenty percent of children worldwide die from respiratory problems of this kind," said Jacques Fellay of the École polytechnique fédérale de Lausanne (EPFL, German: Lausanne Federal Institute of Technology). "It's a silent epidemic."

In an international research collaboration under his leadership, researchers have now found a reason for such complications: mutations in a gene responsible for the detection of certain common cold viruses.

"We were able to confirm that a gene called IFIH1 plays a key role in the body's defense against the most common cold viruses. These viruses cause respiratory infections in children, "said Fellay.

"Normally, this gene allows the recognition of viral RNA (a DNA-like genetic information - the Red.). We have been able to identify the mechanisms that cause children with an IFIH1 mutation to have their immune defenses fail to efficiently target viral infections. "

The body's own defense is blocked
In order to reach their conclusions, the researchers, in collaboration with various clinics in Switzerland and Australia, looked at children who needed intensive care after severe respiratory infections (bronchiolitis or pneumonia).

It was found that eight of the 120 children from the study population had mutations of the IFIH1 gene.

"This gene encodes a protein that recognizes the presence of certain pathogens of common cold, such as respiratory syncytial virus (RSV) or rhinovirus," said Samira Asgari, a researcher at EPFL and responsible for the development of the experiments.

"The protein in question attaches to the RNA of the germ. There it triggers a series of molecular signals and thus an efficient immune system response. "

The researcher has succeeded in demonstrating that three different mutations of the IFIH1 gene prevent the protein from recognizing the viruses and thus block the body's defense against infections.

The results of the study were published in the journal "Proceedings of the National Academy of Sciences" (PNAS).

Which genetic changes affect our immune system?
As early as 2015, a team led by Fellay had studied the genome of more than 2,000 patients in a study to statistically prove which genetic changes affect our immune system against common viral infections.

"These two approaches complement each other," says Fellay. "A study with a large population of studies allows population-level identification of the genes involved, but for individuals, these variations are less important."

"A targeted study that is limited to carefully selected patients, on the other hand, offers the opportunity to explore more rare, more decisive mutations for the participants and to demonstrate the relevant mechanisms."

Prevent and heal
The results of the study may prove useful in the development of new therapeutic targets as well as in prevention:

"At the request of some parents, we also tested the siblings of children who had a gene mutation. This can be used to show whether these children are also more susceptible to infections. In the case of an epidemic, parents now have valid reasons to keep their children at home. In the case of a cold, they know they should go to the hospital quickly. "

For Fellay, these works are prime examples of the methods and objectives of personalized medicine, also called precision medicine:

"The body's defenses vary considerably from one person to another. If we decipher the genetic mechanisms responsible for these differences, we can take more targeted treatment and prevention measures, "the researcher said.

"For example, with a genetic screening in the usual blood tests shortly after birth, you could also determine the susceptibility to infection. At the same time, however, a social discourse must determine which types of genetic tests are desired and which are not. "(Ad)