Preventing instead of provoking

Jul 19, 2010 14:54 GMT  ·  By

Children growing up in farms usually never have asthma, are never allergic and are not prone to hay fever. Scientists wandered for a long time what helped them be so resistant, without getting an answer. Dr. Marcus Peters from the Department of Experimental Pneumology at the Ruhr-Universitaet-Bochum, finally found the answer, even if, as he said, he had to look for the needle in the haystack.

He and fellow researchers collected dust from several farms in Germany, Switzerland and Austria and analyzed its components. They mostly found plant substances of which over ten percent was arabinogalactan. This sugar molecule was found in cowshed dust and scientists believe that it is responsible for protecting children from allergies and asthma. The explanation is simple: even though this is a substance that can cause allergies if inhaled, if within the first year of life, a child is highly exposed to it, the immune system will be inhibited from excessive reactions.

This molecule can be found in large quantities in forage crops like the Meadow Foxtail (Alopecurus pratensis). Scientists from Bochum, Munich and Borstel, under the guidance of Dr. Peters, proved that arabinogalactan affects the cells of the immune system. They tested the mice's immune system's reaction to allergens if molecules of arabinogalactan are present.

The findings implied that the dendritic cells, which trigger the reaction of the immune cells, react differently if the molecule is present, and produce a transmitter that actually suppresses the immune response. Scientists do not know yet which receptors of these dendritic cells are responsible for this phenomenon, but they are determined to find out.

The suppression of the immune system is something that has been seen before in some bacteria. The difference is that arabinogalactan only suppresses the body's extreme reaction to hay, and allows the body to continue in defending itself from pathogenic agents. Allergies an be triggered by low concentrations of Meadow Foxtail pollen, for example, but they also can be prevented if the person is overexposed in the early years. Increasing the dosage is the base of hyposensitization.

Researchers have published their findings in the Journal of Allergy and Clinical Immunology, and their next step is to find out if arabinogalactan can be used only to prevent allergies of if it can also treat them.