Salt could be a key factor in allergic immune reactions

Salt apparently affects allergic immune reactions. A team working with Professor Christina Zielinski of the Technical University of Munich (TUM) demonstrated in cell cultures that salt leads to the formation of Th2 cells. These immune cells are active in allergic conditions such as atopic dermatitis. The team also detected high salt concentrations in the skin of patients.

In industrialized countries, nearly one in three people are allergic to some point in their lives. One in ten children have atopic dermatitis. T cells play an important role in immune conditions of this type. They are a vital part of the body's resistance to infections, but if they are not controlled, they can also develop pathological reactions and start attacking parts of our body or harmless substances such as allergens.

When such functions occur, Th2 cells, a subset of T cells, can cause inflammatory skin conditions such as atopic dermatitis. This involves increased production of interleukin-4 (IL-4) and interleukin-13 (IL-13) proteins. It is still unclear what triggers the dysfunction of the signaling.

More Th2 cells under the influence of sodium ions

Table salt, known scientifically as sodium chloride, is essential to the health of humans and animals. In the body, it occurs in the form of sodium ions and chlorine. In a recent study, Christina Zielinski, DZIF Professor at the Institute of Virology at TUM, and her team were able to demonstrate that sodium chloride can induce a condition in human T cells that causes them to produce a increased amount of IL-13.

The types of T cells, which should not cause allergies, can, in the presence of salt, turn into Th2 cells. The changes are reversed when the T cell is re-exposed to lower salt levels. "As a result, ionic signals play a role in the generation and control of Th2 cells," says Zielinski.

Very high salt levels in the skin of patients with atopic dermatitis

As a specialist dermatologist, Zielinski is naturally interested in atopic dermatitis. His team examined whether the affected skin areas of patients with atopic dermatitis had elevated sodium levels.

"Measuring sodium concentrations in the tissues is complicated," says the study's first author, Julia Matthias. "Salt dissolved in blood can be measured using standard clinical methods, but for the skin, we needed the help of colleagues in nuclear chemistry and physics." They tested the skin samples at the research neutron source Heinz Maier-Leibnitz (FRM II) at TUM and at the Nuclear Chemistry Institute of the University of Mainz by neutron activation analysis. Sodium levels in the affected skin areas in patients with atopic dermatitis have been found to be up to 30 times higher than those of healthy skin.

Ideal conditions for bacteria growing in salty conditions

"The higher sodium levels in the affected skin perfectly match another characteristic of atopic dermatitis," Christina Zielinski said. "It has been known for some time that patients with this disease have high levels of Staphylococcus aureus bacteria on their skin, which are bacteria that thrive in salty conditions, unlike others. commensal bacteria. "Zielinski believes that this idea, as well as others, as well as the results of current research, suggest a link between salt and the onset of atopic dermatitis.

"However, we have not yet been able to show how these large amounts of salt are found in the skin," she said. "For this reason, we also do not know how a low salt or high salt diet could be related to the onset and progression of atopic dermatitis or other allergic conditions." Professor Zielinski and her team hope to answer these and other questions in future interdisciplinary studies.

Provided by
Technical University of Munich