London: Researchers have found that farm dust can protect kids against asthma and allergies, a breakthrough that may ultimately lead to the development of an asthma vaccine.
Researchers have successfully established a causal relationship between exposure to farm dust and protection against asthma and allergies.
It is commonly known that drinking raw cow's milk can provide protection against allergies. A research team, led by professors Bart Lambrecht and Hamida Hammad, both associated with Ghent University and Vlaams Instituut voor Biotechnologie, in Belgium, has now established a scientific basis for this claim.
Many years ago, it was found that children growing up on farms are far better protected against asthma and allergies. However, until recently, scientists were unable to pinpoint why this is the case.
"At this point, we have revealed an actual link between farm dust and protection against asthma and allergies," Lambrecht said.
"We did this by exposing mice to farm dust extract from Germany and Switzerland. These tests revealed that the mice were fully protected against house dust mite allergy, the most common cause for allergies in humans," Lambrecht said.
In addition to the causal relationship, the scientists discovered the mechanism behind this - farm dust makes the mucous membrane inside the respiratory tracts react less severely to allergens such as house dust mite.
"This effect is created by the A20 protein, which the body produces upon contact with farm dust. When we inactivate the A20 protein in the mucous membrane of the lungs, farm dust is no longer able to reduce an allergic or asthmatic reaction," Hammad said.
The findings were then tested in patients. The results showed that people suffering from allergies and asthma have a deficiency in the protective protein A20. It explains why they react to allergens so severely.
"We also assessed a test group of 2,000 children growing up on farms, and found that most of them are protected. Those who are not protected and still develop allergies have a genetic variant of the A20 gene which causes the A20 protein to malfunction," Lambrecht said.
The researchers are now trying to identify the active substance in farm dust that is responsible for providing protection. Once this has been identified, the development of a preventive medicine against asthma may be the next step.
"We already suspect that to some extent, the answer lies in the endotoxines, which form part of the cell wall of specific bacteria," Hammad said.
"Discovering how farm dust provides this type of protection has certainly put us on the right track towards developing an asthma vaccine and new allergy therapies However, several years of research are required still before they will be available to patients," Hammad said.
The study was published in the journal Science.