Author: Laurel Hamers / Source: Science News

Within minutes of biting into peanut-tainted food, people with a peanut allergy may find their pulse quickening, blood pressure plummeting and throat closing up.
They’re experiencing a rapid and sometimes fatal allergic reaction called anaphylaxis.New research in mice explains how even a small amount of an allergen can quickly trigger such a strong, full-body reaction. The culprit is a type of cell that probes the bloodstream for allergens and then broadcasts the invaders’ presence to anaphylaxis-inducing immune cells, researchers report in the Nov. 9 Science.
When these immune cells, called mast cells, detect an allergen that they’re sensitized to, they flood the body with inflammatory proteins that set off an allergic reaction. But how mast cells, which line the space surrounding blood vessels, are so efficient at detecting allergens floating along in the blood has been a long-standing question, says Stephen Galli, an immunologist at Stanford University who wasn’t involved in the research. In the case of a snakebite, fangs can pierce blood vessels and make it easy for venom, which also activates mast cells, to reach the cells. But with a food allergy, the vessels are usually intact.
In the study,…
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