Researchers at the CPC-M site of the German Center for Lung Research (DZL), together with partner institutions, have published a new study presenting a promising therapeutic strategy for allergic asthma. In the paper, released in the journal Allergy, the team shows how an extract derived from farm dust (Farm Dust Extract, FDE) can influence key asthma mechanisms.
Asthma affects more than 355 million people worldwide and causes major health and economic burdens. Current standard treatment relies on inhaled corticosteroids—effective, but associated with side effects and insufficient impact in some patients.
Lower allergy risk in rural areas
Epidemiological studies have long shown that people living in rural environments—especially those exposed to farm dust—tend to have a lower risk of asthma and allergies. This led to an important question: Could such an environmental extract not only help prevent asthma but also serve as a treatment for already established disease?
In a mouse model of ovalbumin (OVA)–induced allergic airway inflammation, the farm dust extract was administered after sensitization and during allergen exposure—a strategy comparable to early intervention or secondary prevention.
The researchers examined several features of asthmatic inflammation, including the number of eosinophils in the airways, airway hyperresponsiveness, mucus production, and IgE levels. They also studied how the extract acted on a cellular level—on regulatory T cells, the phenotype and behavior of dendritic cells, the integrity of the airway epithelial barrier, and specific immune signaling molecules.
Additional experiments using peripheral blood mononuclear cells (PBMCs) from patients with asthma were conducted to explore potential relevance for humans.
Farm dust extract shown to be as effective as corticosteroids
The study demonstrates that the farm dust extract significantly reduced typical airway inflammation in asthmatic mice and markedly decreased airway hyperresponsiveness—effects comparable to treatment with the corticosteroid dexamethasone. At the same time, the extract shifted the immune response toward a more balanced, anti-inflammatory state: the number of regulatory T cells increased, while inflammatory immune cells were dampened. The protective epithelial barrier of the airways—often impaired in people with asthma—was also strengthened. In addition, levels of the signaling molecule IL-33 increased, which, together with amphiregulin (AREG) and regulatory T cells, helps maintain a healthy balance between immune activity and mucosal protection.
Supplementary experiments in human blood cells confirmed these findings: regulatory T cell numbers increased, while inflammation-promoting Th2 cells decreased. These results suggest that the farm dust extract may exert anti-inflammatory and protective effects not only in animals but potentially in humans as well.
The findings are noteworthy for several reasons. They show that an environmental, farm dust–derived extract may offer not only preventive but also therapeutic benefits in established allergic asthma. This approach could pave the way for additional or alternative treatments to corticosteroids—potentially with fewer side effects. The results from human cell experiments further support the possibility that this line of research may eventually contribute to future patient care.
