Salt could be a key factor
Salt apparently affects allergic immune reactions. A team at LMU and TUM has demonstrated in cell cultures that salt stimulates the formation of Th2 cells. These immune cells are active in allergic conditions such as atopic dermatitis.
In industrial countries, nearly one in three people are affected by allergies at some point in their lives. One in ten children suffer from atopic dermatitis. T-cells play an important role in immune conditions of this kind. They are a vital aspect of the body's resistance to infections, but, if uncontrolled, can also develop pathological responses and start attacking parts of our bodies or innocuous substances such as allergens.
When such responses occur, Th2 cells, a subgroup of T cells, can cause inflammatory skin conditions such as atopic dermatitis. This involves increased production of the proteins interleukin 4 (IL-4) and interleukin 13 (IL-13). It is still unknown what triggers the signalling malfunction.
Increased salt levels promote formation of Th2 cells
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 and chlorine ions. In the new study, the researchers led by Christina Zielinski (Professor at TUM), in collaboration with Dr. Dirk Baumjohann, leader of an Emmy Noether research group at LMU, and Julia Maul (LMU), were able to demonstrate that sodium chloride can induce a state in human T cells that causes them to produce increased amounts of the proteins IL-4 and IL-13.
Types of T-cells, which normally do not cause allergies, can, in the presence of increased salt concentrations, turn into Th2 cells. The changes are reversed when the T cells are again exposed to lower salt levels. “Consequently, ionic signals play a role in the generation and control of Th2 cells,” says Christina Zielinski. The team also detected elevated salt concentrations in the skin of dermatitis patients.
How a low-salt or high-salt diet might be related to the appearance and progression of atopic dermatitis or other allergic conditions, is one of the questions the researchers hope to answer in future interdisciplinary studies.
- J. Matthias, J. Maul, R. Noster, H. Meinl, Y.-Y. Chao, H. Gerstenberg, F. Jeschke, G. Gasparoni, A. Welle, J. Walter, K. Nordström, K. Eberhardt, D. Renisch, S. Donakonda, P. Knolle, D. Soll, S. Grabbe, N. Garzorz-Stark, K. Eyerich, T. Biedermann, D. Baumjohann, C. E. Zielinski: Sodium chloride is an ionic checkpoint for human TH2 cells and shapes the atopic skin microenvironment, Science Translational Medicine (2019).