New Test for Peanut Allergies

Arah2 peanut protein can be used to determine peanut allergy

(RxWiki News) Need to take an oral food challenge to determine a peanut allergy? That's nuts. A new study has identified a new target to test for peanut allergies.

Researchers have developed a two-step test to diagnose peanut allergies in patients. By isolating a part of the peanut protein that individuals are allergic to, Arah2, researchers can use a blood test to determine peanut allergy. This would reduce cost for families and reduce the number of oral food challenges which could lead to a severe reaction like anaphylaxis.

"Ask your doctor if your child should take a food allergy test."

The study was led by Thanh Dang, a doctoral candidate at the University of Melbourne from the Murdoch Children's Research Institute and involved 200 infants. Researchers isolated Arah2 in the peanut protein that individuals are allergic to. Of the 200 infants, 100 were allergic to peanuts and 100 were peanut tolerant. 

The two-step process involves a blood test as well as a second test using Arah2, which is the most commonly found peanut allergen in individuals with a peanut allergy.  An allergy causes the immune system to produce a certain antibody, Immunoglbulin E (IgE), in response to a specific allergen, like a peanut. In this study the blood test is looking for the whole peanut-specific IgE level. The second step of the process has researchers looking for Arah2 IgE levels. 

Using blood tests alone cannot determine a peanut allergy. In the study, the blood test looking for the whole peanut-specific IgE level had a 26 percent accuracy in determining a peanut allergy. Oral food challenges, after evaluating family history and other risk factors associated to food allergies, are the only definitive way of determining a food allergy. Allergists expose a child to the food they are possibly allergic to and determine the allergic reaction to the food in question.

While oral food challenges can determine a food allergy, it can be costly and can lead to severe allergic reactions like anaphylaxis. Adding the Arah2 IgE level test improved the accuracy of the blood test and can reduce the need for an oral challenge by four-fold, according to researchers. The Arah2 test could reduce the time spent in a doctor's office as well as the cost for the family while avoiding a serious reaction like anaphylaxis.

 If a child has no history of food allergies or shows no signs of an allergic reaction, testing for food allergies is not needed.

The Arah2 IgE test could reduce the number of oral food challenges, according to researchers. Using a blood testing for peanut-specific IgE levels and Arah2 IgE levels could be a cost-effective and accurate tool for families in the near future.

No funding information was reported.

This study will be published in the April edition of the Journal of Allergy and Clinical Immunology.

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Review Date: 
March 26, 2012