Research on a Roll

in Food Allergy
Published: August 27, 2010

Idea: Test for Anaphylaxis

What’s Involved: The theory is that levels of a molecule in the blood called platelet-activating factor (PAF) and the enzyme that destroys it – platelet-activating factor acetylhydrolase (PAF-AH) – can help allergists to predict the severity of an individual’s reactions to peanuts, and possibly other allergens. PAF is what researchers term “a bad guy,” bringing on anaphylaxis symptoms such as airway inflammation and dropping blood pressure. Early results of research led by Dr. Peter Vadas, director of allergy and immunology at Toronto’s St. Michael’s Hospital, suggest the possibility of blood tests for these two biological markers, and possibly others. Test findings would help to identify those who face the higher risk of anaphylaxis, enabling physicians to reinforce with such patients the importance of allergy precautions, auto-injectors and a plan for an emergency.

Where We Stand: Vadas and his colleagues have now teased out another marker of anaphylaxis risk. They found people with a history of serious reactions had peanut-specific IgE (the antibody that recognizes peanut as an invader in the allergic) at high levels in the blood along with low levels of PAF-AH. These results haven’t been published yet, and any test using this knowledge still hinges on verification by independent researchers. So Vadas finds it difficult to predict when patients will be offered his test in the allergist’s office.

While it’s also possible this team could develop a drug that interferes with PAF to halt anaphylaxis, testing such a drug is proving problematic. That’s because to study its effectiveness, doctors would have to administer the drug during an anaphylactic reaction, instead of epinephrine, and that could put lives at risk. It’s more likely a drug would be used as a long-term, preventative treatment for allergies, says Vadas, adding that such a study could take years.

Idea: Hypoallergenic Peanut

What’s Involved: Developing a genetically engineered hypoallergenic peanut has been Dr. Hortense Dodo’s goal for at least 10 years. In 2005, she announced she had eliminated the major allergen, Ara h2, using a process called RNA interference technology. Meanwhile, in 2007, Dr. Mohamed Ahmedna made headlines when North Carolina Agricultural and Technical State University announced that the researcher had developed a process which renders peanuts non-allergenic following harvest.

Where We Stand: In the past few years Dodo has managed to silence two other major allergenic peanut proteins, Ara h1 and Ara h3, and likely two minor allergens. She hopes to one day “gradually replace part of the peanut market,” with products clearly labeled to show they were made with hypo-allergenic peanuts. Then, if someone was to ingest the peanut accidentally, there would be less risk of a severe reaction. But, Dodo cautions there is still a lot of testing and regulatory approval that needs to take place before her peanuts show up on the shelves of grocery stores.
Ahmedna is set to begin testing his peanuts, which are treated with a process that changes the structure of the proteins, in humans, using skin-prick and other tests to see if there is a significant decrease in allergenicity. Like Dodo, he hopes his peanuts will be used by commercial manufacturers in the future.

There are concerns in the allergy community, however, about the practical application of hypoallergenic peanuts. “There is huge potential for confusion if both allergenic and hypoallergenic peanuts begin circulating,” says Toronto allergist Dr. Peter Vadas. “How could a kid in a school lunchroom tell the difference between hypoallergenic peanut butter smeared on a table and the real thing?”

First published in Allergic Living magazine.
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