Microbial exposure may block respiratory allergies for months, study reveals

A new study led by scientists at France's Pasteur Institute has uncovered a potential way to prevent respiratory allergies. The research shows that exposing mice to microbial fragments can block allergic reactions for months. This finding could lead to new treatments for conditions like pollen allergies and allergic asthma, which have risen sharply in recent years.

In the experiments, mice were first exposed to viral or bacterial fragments before being given an allergen. Those with prior microbial exposure remained fully protected for at least six weeks. Further tests revealed that this protection lasted for over three months.

The study found that the lungs developed a form of immunological memory after contact with microbial fragments. This memory prevented severe allergic reactions upon later exposure to allergens. Without this initial protective exposure, the mice developed lung hypersensitivity and suffered strong allergic responses when re-exposed.

Researchers also identified a news role for fibroblasts, the connective tissue cells in the lungs. These cells underwent epigenetic changes that helped block allergic reactions. The discovery suggests that targeting fibroblasts could be a new approach in allergy prevention.

The rise in respiratory allergies has been notable in Germany, where pollen allergies and allergic asthma have increased by 20-30% over the past decade. Experts at the German Allergy and Asthma Association (DAAB) and the Robert Koch Institute link this trend to climate change, which has extended pollen seasons, worsened air pollution, and increased pollen potency due to higher CO₂ levels.

The findings open up clinical possibilities for long-term allergy prevention. By triggering immunological memory in the lungs, microbial exposure could offer lasting protection against respiratory allergies. Further research may confirm whether similar effects occur in humans, potentially leading to new preventive treatments.