Genes determine who gets an allergy

Whether someone gets an allergy is highly dependent on genetic factors

Pollen, animal hair, various foods: Triggers for allergies are truly enough. But why do some people have allergic reactions to certain substances and others? Researchers have now discovered that it depends heavily on genetic factors for anyone to develop an allergy.

Over 20,000 different triggers of allergies

According to an older survey, about every third adult in Germany is allergic. And every third child suffers from an allergy, as the AOK children's report showed last year. There are plenty of possible causes: "Over 20,000 different triggers of allergies are known today," writes the German Allergy and Asthma Association (DAAB) on its website. Particularly common are pollen allergies and food allergies. But why do some people have allergic reactions to certain substances and others? According to researchers, our genes determine who gets an allergy.

Pet hair, pollen, food: There is a lot that leads to allergic reactions in some people. But why do some people develop an allergy while others do not? According to researchers, this is determined by genetic factors. (Image: Africa Studio / fotolia.com)

Strongly dependent on genetic factors

Whether or not someone develops an allergy depends heavily on genetic factors. This is the key finding of a study published in the journal "EbioMedicine" under the direction of Winfried F. Pickl from the Institute of Immunology of the Medical University (MedUni) Vienna.

According to a statement of the university, the Austrian researchers were able to show by example that in the development of an allergy to the weed mugwort - assuming contact with the allergen source - the gene HLA-DR1 as well as allergen-specific, reactive T cells play an important role.

It has long been suspected that HLA molecules are generally of great importance in autoimmune diseases, chronic infections and allergies.

Explosive outbreak of asthma

In the current study, the scientists from MedUni Vienna were able to demonstrate for the first time in four mouse models worldwide that only those mice could develop the mugwort allergy that had the HLADR1 gene.

At the same time, the allergen-specific, reactive T cells were in excess of the regulatory ones, "and there was an explosive outbreak of asthma and the formation of disease-causing allergen-specific immunoglobulin E," explains Pickl.

In this case, the mugwort allergen was supplied in the normal way as in humans via the respiratory tract. The proof could only be provided so precisely because the research group used so-called humanized mice.

"These are animals that carry a human T-cell receptor that is specific to the allergen and that also has human HLA molecules (note: in this case, HLA-DR1) on their antigen-presenting cells. Thus, our new model is the first that reflects the situation in humans, "explains Pickl.

The scientists were able to show that the administration of the T cell growth factor interleukin-2 helps to stimulate regulatory T cells and prevent allergic asthma.

Allergy vaccinations as a vision

"This way, we now know how the system creates the allergy on the molecular pathway and can intervene much better preventively and therapeutically in the future," says Pickl.

This opens up great future possibilities for future allergy vaccinations in humans, also preventive for risk groups, similar to a common vaccination.

For example, the HLA determination together with an allergy chip test could determine the risk of future allergies in early childhood and, if necessary, initiate therapy measures at an early stage.

"The model described in the current study is specific to the key allergen from mugwort, we are working to develop similar model systems for all allergies." (Ad)