London, Nov 19 : Researchers from University of Zurich in Switzerland claim to have unravelled the mystery behind why some people are prone to occasionally deadly allergic reactions due to bee sting, while others are not.
While conducting the study over beekeepers faced with daily stings in their work, the research team found that high doses of bee venom early in the year block an important immune reaction for the remaining season, thus making them less likely to develop severe allergies.
During the study, the researchers tracked a group of beekeepers for several years to determine how their immune systems managed to cope up with the allergies. Bee stings often trigger immune reaction including inflammation, swelling and pain.
But in the new study, the researchers found that after an average of 13 stings a week, beekeepers quickly desensitise to the bees' attacks, which delivers a large dose of several venoms, including a membrane-busting protein called phospholipase A.
Early bee attacks activated the production of histamine, a chemical that drives allergic reactions.
As the beekeeper was stung several times, a class of T-cell that would normally boost the immune response against the attack instead senses the histamine and transforms into regulatory T-cells, thus calming the immune response.
While a normal person's immune system triggered inflammation and pain, a venom-tolerant beekeeper's extra regulatory T-cells ensure the response is calm.
These regulatory T-cells inhibited the production of more histamine, thus making the beekeepers less prone to bee sting related allergies.
"What makes the difference between people that develop allergy and those that become tolerant? This is exactly the mechanism that's going on in the case of beekeepers each year," New Scientist quoted lead researcher Mubeccel Akdis, an immunologist at University of Zurich in Switzerland.
They hope that the new discovery would help in treating the roughly 2pct to 5pct of people who develop severe allergies to bee stings.