Immune responses to peanuts are key in a growing allergic phenomenon

Food allergies are common in infants in the first 3 years of life, but often decrease in prevalence in older children and adults. One exception is peanut allergy, which affects up to 1.5 million Americans and accounts for nearly 30,000 food-induced allergic reactions documented in emergency departments annually. In the United States, an average of 200 people die each year from food-induced anaphylaxis. Those with severe allergies must carry an emergency dose of epinephrine and avoid offending foods. However, the widespread use of peanut products in a variety of foods means that accidental exposure to this particular antigen is common.

In the April 1 issue of the Journal of Clinical Investigation, Gideon Lack and colleagues from St. Mary's Hospital at Imperial College, London report important differences in the immune responses among children with peanut allergy, children who have outgrown peanut allergy, and non-allergic children. Using a novel technique, they identified the rare cells of the immune system that respond to peanut proteins.

The researchers found that in response to peanut exposure, the immune cells of children with peanut allergy produced different immunological factors when compared to cells from non-allergic children or children who had outgrown their peanut allergies. These factors act to induce and sustain the associated cascade of allergic responses.

It has been previously suggested that certain antigens might possess intrinsic properties that render them allergenic. In the current study, the finding that the same peanut antigen extract induced different immunological responses in peanut-allergic individuals compared to non-allergic children suggests that the development of the allergic reaction seems to depend on the host immune response rather than on inherent properties of the allergen. The authors demonstrate that children with peanut allergy possess abnormal immune function and these abnormalities revert to normal when an allergy is outgrown. These findings will be important in designing and monitoring future treatments for peanut allergy.

In his accompanying commentary, Wesley Burks - a leading allergy specialist at Arkansas Children's Hospital – discusses some of the most recent developments in the treatment of food allergy that are designed to alter the immune system's response to food allergens. He further comments that "the goal of peanut-specific immunotherapy would not be to allow patients to eat peanuts at will, but rather to give them some protection in case of accidental ingestion".

CONTACT:
Gideon Lack
St. Mary's Hospital
Ground Floor
Salton House
Praed Street
London W2 1NY,
GREAT BRITAIN
Phone 1-44-207-886-6384
Fax 1-44-207-886-1129
E-mail: gideon.lack@st-marys.nhs.uk.

View the PDF of this article at:
http://www.jci.org/cgi/content/full/111/7/1065

ACCOMPANYING COMMENTARY:
Peanut allergy: a growing phenomenon

CONTACT:
Wesley A. Burks
Arkansas Children's Hospital
1120 Marshall Street
Slot 512-13
Little Rock, AR 72202
USA
Phone 1-501-320-1060
Fax: 501-320-3551
E-mail: burkswesley@exchange.uams.edu

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