Researchers have known for decades that children who grow up on a farm are less likely to be pestered by asthma or allergies later in life, but a group of Belgian researchers believe that they found the reason why.
Their study reveals that the secret lies within farm dust. Researchers explained that the microorganisms found in farm dust prompted the immune system of lab mice to react. That reaction shielded the animals from allergies and asthma for months.
The finding may be of exceptional importance since 17 percent of children are diagnosed with one form or another of respiratory allergies. In the U.S., respiratory allergies are the most widespread type of allergy in kids. Moreover, nearly 7 million U.S. children have asthma.
On the other hand, past studies had shown that not all locations of the U.S. are affected by the asthma epidemic. Children living in rural areas, especially in farms with cows, display significantly lower rates of respiratory allergies and asthma.
Scientists doesn’t recommend urban kids to move to a farm, but they hope that their finding may help medical research develop medications that can trigger in the body the same immune response as farm dust does.
The research team disclosed that they based their findings on laboratory mice, but the results may also apply to humans. They used two groups of mice. One group was exposed to bacteria that thrive in farm dust for nearly 2 weeks. Next they tried to induce a dust allergy in both groups of animals. Only, the mice that weren’t exposed to dust bacteria developed the disease.
Laboratory tests showed that a lung molecule called A20 may be responsible for the immune response. In order to test that theory, the team grew laboratory rodents that didn’t have the molecule in their lungs. As a result, they still got ill although they had been exposed to farm dust bacteria.
Researchers concluded that children who grew up on farms and still had respiratory allergies had a genetic mutation that prevented their bodies from producing significant quantities of A20.
When they switched to human lung tissue, researchers learned another interesting fact. Healthy human tissue had a normal reaction to dust bacteria, but in lung tissue from asthma patients the immune response to dust bacteria was exaggerated and the production of A20 molecules was much lower.
Bart Lambrecht, senior author of the study and researcher at Ghent University in Belgium, said that the study clearly shows that farm dust does directly affect the immune system. Instead it interacts with cells in lung tissue. When the cells get in contact with farm dust they are somehow permanently “numbed,” so they won’t be able to trigger the alarm whenever a common allergen enters the body later in life. Allergies are an overblown response to a “false alarm.”
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