26 Nov 2024
For small children, it acts like a protective elixir against asthma and other allergies from birth: the dust from the traditional cowshed. Researchers are keen to find out exactly what causes this effect.
However, deciphering this in terms of allergy prevention is a lengthy process, which has now taken another step forward: researchers at the Dr. von Hauner Children's Hospital at LMU Klinikum have analyzed how cells of the immune system react to stable dust and thus contribute to the "protective farm effect". The results were recently published in the journal "Allergy".
The hygiene hypothesis is now well established in science. Tenor: The child's immune system should be "trained", especially in the preschool years, through regular contact with certain "good" microorganisms. The immune system must learn not to react excessively and not to attack harmless substances or turn against the body's own structures.
Dust from the cowshed has a preventive effect
Researchers at the Dr. von Hauner Children's Hospital at LMU Klinikum München have shown that frequent and continuous contact of young children with the farm environment, in particular with dust from the cowshed, has a preventive effect. Children growing up there, for example, develop significantly less asthma than those who live in the city. Based on these findings from epidemiological studies, scientists are researching the fundamentals of this phenomenon in their laboratories around the world.
What changes in the immune system through stimulation with stable dust?
On the one hand, they want to know which specific substances or microorganisms trigger the protective effect. On the other hand, they are interested in what exactly changes in the immune system so that it does not attack the body's own or harmless structures and a healthy balance of the immune system is established. A team led by Prof. Dr. Bianca Schaub has now taken a major step forward in this direction. They have stimulated various immune cells in the blood with stable dust in a cell culture approach in the laboratory.
Study shows: Stable dust affects the immune system of children already suffering from asthma
"We were able to show that in children with manifest asthma, certain cells of the innate immune system are reduced after stimulation with farm dust," says Claudia Beerweiler, first author of the study, "whereas subgroups of cells of the acquired immune system are increased, including B cells and certain T helper cell populations. In addition, certain molecules associated with inflammation, cell toxicity, antigen presentation and specific T helper cells are reduced. Cell toxicity is the ability of certain substances or microorganisms to damage or destroy cells. Antigen presentation is a central process in an immune response in which structures of microorganisms are made recognizable to certain immune cells.
Anti-inflammatory effect already proven in earlier studies
"We now know that the innate immune system is much more central to allergy development and prevention than we thought for decades," says Bianca Schaub, LMU Professor at the Children's Hospital and Pediatric Polyclinic at the Dr. von Hauner Children's Hospital, with a focus on pediatric pneumology and allergology at the LMU Clinic. Previous studies have already shown that the protection provided by farmyard dust is mediated via an anti-inflammatory effect.
In a recently published study involving LMU researcher Prof. Dr. Erika von Mutius, it was found that dusts from cowsheds contain transport proteins known as lipokalins. They modulate the function of the human immune system. Two of these substances are found at significantly higher levels in barn dust.
Findings open up new ways of treating sick children
One building block follows another to unravel the mystery of barn dust. The researchers' goal is clear: to identify the beneficial substances and make them available to all those children who do not live on the farm - the form in which this is done is currently being investigated. The target group of children that could be treated in this way also still needs to be investigated in detail. "The fact that stimulation with stable dust can modulate immune responses in the laboratory, even in asthmatics with the disease," says Bianca Schaub, "may also open up new avenues for treating children who are already symptomatic."
Original publication:
Farm-dust mediated protection of childhood asthma: Mass cytometry reveals novel cellular regulation
Claudia Carina Beerweiler, Michael Salvermoser, Johanna Theodorou, Andreas Böck, Franziska Sattler, Paulina Kulig, Vinko Tosevski, Bianca Schaub | Allergy. 2024 Nov;79(11):3022-3035. doi: 10.1111/all.16347. Epub 2024 Oct 14.
https://doi.org/10.1111/all.16347