Cienciaes.com: A new type of antiallergic lymphocyte.

2020-07-14 19:25:03

Approximately 25% of people suffer from some type of allergy. These can be mild or extremely dangerous and even cause death, as can happen in an acute attack of asthma, or in anaphylactic shock.

It is not known why some people develop allergies to a particular substance and others do not, despite the fact that the substance may be virtually ubiquitous and almost literally everywhere. One of these ever-present substances is dust mites, made up of the remains of the bodies of these microscopic arachnids that eat and sleep with us.

To try to figure out what might be the reasons for differences in allergy susceptibility between people, researchers at the La Jolla Institute for Immunology in California are using one of the most powerful techniques in molecular biology. This technique makes it possible to analyze the genes that are functioning in individual cells and compare them with each other.

In this way, the researchers are able to analyze the genes that are functioning in the type of cell of the immune system that is most important for the development of allergies: the T lymphocytes. The scientists analyze populations of 50,000 T lymphocytes taken from three groups of patients with allergies or from healthy people, and study the different types of T lymphocytes present in those populations. The three groups of allergic people include people with allergic asthma and dust mite allergy, people with dust mite allergy but not asthma, and people who have asthma but not dust mite allergy.
The “personality” of the cells of the organism depends on the set of genes that they have functioning. The scientists thus found out that people with asthma and allergies to dust mites have an excess of a well-known type of lymphocytes, called TH2-IL-9. These lymphocytes produce high amounts of the cytokine IL-9, which stimulates allergic reactions.

However, non-allergic people have more of a new type of T lymphocyte with a hitherto unidentified “personality”, that is, with a particular previously unidentified set of active genes. This new type of T lymphocyte produces high amounts of the cytokine called TRAIL, which can induce the death of certain cells, among which it is suspected that lymphocytes of the previous type, TH2-IL-9, may be found. In this way, the production of these new lymphocytes TRAIL would protect from the development of allergies.

These new discoveries represent important progress in the understanding of the immune system and allergic reactions, although the reasons that lead to the development of one or another type of T lymphocyte remain unknown. These new advances make it possible to consider new therapeutic strategies. for the treatment of allergies that attempt to block the activity of the cytokine IL-9 and that enhance the activity of the cytokine TRAIL. This is good news for the billions of allergy sufferers in the world.

Reference:
Seumois et al., Sci. Immunol. 5, eaba6087 (2020) 12 June 2020.

Jorge Laborda, July 12, 2020

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