Risky Allergic Reaction: Chemical Clues
Inflammatory Chemical Called PAF Linked to Anaphylaxis
WebMD News Archive
Jan. 4, 2008 -- Researchers have found two chemical clues that may help them
tame sudden, severe allergic reaction (anaphylaxis).
The first clue: People with anaphlyaxis have high blood levels of an
inflammatory chemical called platelet-activating factor (PAF).
The second clue: Anaphylaxis patients have low blood levels of PAF
acetylhydrolase, an enzyme that breaks down PAF.
Those patterns may lead to new drugs to block PAF and treat anaphylaxis, Canadian
The scientists compared blood samples from anaphylaxis patients to those
from people without anaphylaxis. They concluded that too much PAF and too
little PAF acetylhydrolase were a dangerous combination, and the greater the
gap between levels of the two chemicals, the greater the risk to the
But PAF didn't cause anaphylaxis by itself. The patient also had to come in
contact with his or her allergen, which for some patients was peanuts or
Peter Vadas, MD, PhD, and colleagues report their findings in The New
England Journal of Medicine. Vadas works in Toronto at St. Michael's
The study may also lead to better tests to diagnose anaphylaxis, writes A.
Wesley Burks, MD, in an editorial published with the study. Burks works in the
allergy and immunology division of Duke University Medical Center's pediatrics