IMMUNOLOGY

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Oral Immunotherapy Shows Promise as Treatment for Egg Allergy

 

Children with egg allergy, one of the most common childhood food allergies, are at risk for severe reactions if they are accidentally exposed to egg-containing foods. Symptoms of allergic reactions can range from mild (hives, redness and itchiness of the skin) to severe (swelling of the back of the throat, trouble breathing, drop in blood pressure, and faintness or dizziness). Currently, the only way to prevent these reactions from occurring is to avoid foods that contain eggs.

 

According to an article published online in the New England Journal of Medicine (19 July 2012), giving children and adolescents with egg allergy small but increasing daily doses of egg white powder, holds the possibility of developing a way to enable some children to eat egg-containing foods without having allergic reactions.

 

The study is one of several federally funded trials of oral immunotherapy (OIT), an approach in which a person with food allergy consumes gradually increasing amounts of the allergenic food as a way to treat the allergy. Because OIT carries significant risk for allergic reactions, these studies are all conducted under the guidance of trained clinicians.

 

The goals of the study were to determine if daily egg OIT reduced or eliminated participants’ allergic responses to egg protein and if it did, whether or not the benefit persisted after therapy was stopped for four to six weeks. The Consortium of Food Allergy Research (CoFAR) study enrolled 55 children and adolescents aged 5 to 18 years who had egg allergy. Participants were randomly assigned either to the treatment group, which received egg OIT (40 participants), or to the control group, which did not (15 participants). Both groups were followed for 24 months.

 

Participants received a daily dose of egg white powder or cornstarch powder (placebo) at home. Authors gradually increased the dose of egg or placebo powder every two weeks until the children in the egg OIT group were eating the equivalent of about one-third of an egg every day. Participants came to the clinic to have three oral food challenges, at 10 months, 22 months and 24 months, with the maximum challenge equivalent to one egg. The challenge was deemed successful if there were either no symptoms or only transient symptoms not directly observable by a doctor, such as throat discomfort. Participants failed the challenge if they had a symptom that could be observed by a doctor, such as wheezing.

 

Results showed that after 10 months, none of the participants who received placebo passed the challenge, but 55% of those on egg OIT did. After 22 months of egg OIT, a second oral food challenge was given to all of the children in the treatment group. At this food challenge, 75% of those on egg OIT passed.

 

To determine if egg OIT had any long-term benefit on treating the children’s food allergy, the participants who passed the 22-month test were completely removed from egg OIT for four to six weeks and then rechallenged at 24 months. Eleven of the original 40 children (about 27%) passed this third food challenge. None of the children from the placebo group were retested because they had failed the prior food challenges. The 11 children who passed the third test were allowed to eat egg or egg-containing foods in their normal diets as frequently or infrequently as they chose. At a one-year follow-up, they reported no symptoms.

 

According to the study authors, these results indicate two types of benefits. First, the majority of the study children could be safely exposed to egg while on egg OIT. Second, a small group of children — approximately one-fourth — were able to eat egg in their regular diets even after stopping OIT for four to six weeks.

 

The authors noted that although these results indicate that OIT may help resolve certain food allergies, this type of therapy is still in its early experimental stages and more research is needed. The authors also emphasized that food OIT and oral food challenges should not be tried at home because of the risk of severe allergic reactions.

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