Food Allergy Counseling

Food Allergy Counseling
Sloane Miller, Food Allergy Counselor (Picture © Noel Malcolm 2013)

Friday, September 29, 2006

Peanuts To Be Genetically Altered

No, not those Peanuts; the ones that grow in the ground. Seems to be Gene-week in the news, especially concerning nut allergies.

My dear buddy Steve sent me a WSJ article about a peanut-allergy vaccine [SEE BELOW]. "If you take out all those proteins that cause allergic reactions to the peanut, then you no longer have a peanut."—This is by far the most amusing quote.

This week's gene posts have stimulated a question--what would I rather: genetic deletion of the nut proteins, thus creating a potential allergy-free existence for me and millions others? Or for geneticists to leave well enough alone and for the rest of us to have to be as careful as we already are and take the risks we do every day when we eat something we didn’t make ourselves.

Here’s the thing, a non-allergic life is one I can barely imagine; rather, I don’t allow myself that particular daydream. And I have very strong feelings about not messing about with Mother Nature, genes included. I think that even extends toward something that could potentially kill me. So which side does that put me on--pro-gene alteration or pro-leave it alone? Clearly, I have to think about this question further.




Taming Peanut Allergy
Takes Researchers
Down Uncertain Road
By JANE ZHANG
September 29, 2006; Page B1
In a world of wheat-free cookies and dairy-free ice cream, the peanut industry is helping fund the quest for a "nut-free" peanut.

Peanuts aren't nuts at all, of course, but legumes, or seeds, as are beans and lentils. An estimated 1.5 million Americans, including some 600,000 children, experience allergic reactions to peanuts, ranging from hives to nausea to sometimes-fatal anaphylactic shock. With most of the annual 150 food-allergy deaths blamed on peanuts, many schools have created peanut-free zones or gone totally "peanut free."
The number of children with peanut allergies has skyrocketed, doubling from 1997 to 2002, according to a study in the Journal of Allergy and Clinical Immunology. And it's a mystery why peanut allergies are causing more problems. One explanation is that physicians are more adept at detecting them. Another is that the modern environment may be, in a sense, too clean: If the human immune system were exposed to more allergens, a peanut might not send it into overdrive.

An approved asthma drug, Xolair, may be useful in treating peanut and other food allergies; injected into patients, it would reduce certain antibodies that are thought to cause anaphylactic food allergy. Last year, though, clinical trials came to a halt after two children, who had been given peanut protein in a screening to gauge the severity of their allergy, experienced anaphylactic reactions. The drug's makers -- Genentech, Novartis and Tanox -- are working with the Food and Drug Administration to design a new trial, Genentech says.

Determined scientists, in some cases with peanut-industry funding, are trying to develop other therapies, or a vaccine, to prevent or reduce the severity of peanut reactions. A nut-free peanut would be genetically altered so that it is less likely to set off an immune response. Peanut farmers and food processors have given $5.6 million over the past decade to eight scientists, mainly for peanut-allergy work, says Howard Valentine, of the American Peanut Council.

Two researchers -- Wesley Burks, chief of pediatric allergy and immunology at Duke University Medical Center, and Hugh Sampson, his counterpart at New York's Mount Sinai School of Medicine -- are trying to create a vaccine. They have slightly modified the three peanut proteins responsible for most reactions so they don't trigger such strong reactions from human mast cells. By administering the modified proteins to subjects in slowly increasing doses, they hope to condition their immune systems to tolerate more. They have tested the therapy on mice and plan to start on humans in a year or so.

Another experimental therapy aims to reduce the severity of reactions. Dr. Burks's team administers powdered or liquid peanut proteins to patients in incrementally increasing doses, starting with 0.001 peanut the first day, to one whole peanut six months later. They hope one day to develop a drug or a physician-administered therapy. In a trial completed on eight patients, Dr. Burks says the subjects tolerated 13 peanuts before experiencing a reaction -- enough, in theory, to save an allergic child's life in case of accidental ingestion.

Peanut interests have helped to fund the work of Peggy Ozias-Akins, a horticulture professor at the University of Georgia, Tifton. She wants to develop a plant whose peanuts are free of the three major protein allergens.

Screening the genetic structure of peanuts harvested on an experimental farm, Dr. Ozias-Akins is searching for ones with a defunct Ara h 2 gene, which is responsible for a protein that causes reactions in about 90% of patients with peanut allergy. When she finds plants with the defunct gene, she'll use them in a traditional breeding program to produce less-allergenic plants. She expects it will take at least three years to breed the plants and test them in animals.

Dr. Ozias-Akins's team also is trying to disable the Ara h 2 gene by modifying the peanut plant's genetic structure. She shoots cloned copies of the gene into a peanut, which can create a disabled gene that suppresses the function of the original one. Her team is growing plants with a disabled Ara h 2 gene in the greenhouse and testing whether the peanuts contain the allergy-causing protein.
Success is a long way off. Without the protein, other genes may compensate for its loss, making the new plants more, not less, allergenic than regular peanuts. As a result, any new genetically modified food product would have to go through animal testing and human clinical trials.

And even if Dr. Ozias-Akins gets there, it isn't clear that the world will embrace the results of her work. Says Duke's Dr. Burks, "If you take out all those proteins that cause allergic reactions to the peanut, then you no longer have a peanut."
Consumers may reject a genetically modified nut-free peanut. Dr. Ozias-Akins is aware of the skeptics but hopes the benefits will outweigh concerns. "Nothing -- or very little -- we eat today is natural or hasn't been exposed to artificial selection," she says.

"It's the best solution on the horizon right now," says Don Koehler, executive director of Georgia Peanut Commission. "We may never have an allergen-free peanut, but you've got to try. You've got to dream a little."

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