April 12, 2010
Eggs can ease egg allergies, oral immunotherapy study shows
Children with egg allergies who consume increasingly higher doses of egg protein—the very nutrient they react to—appear to gradually overcome their allergies, tolerating eggs better over time and with milder symptoms, according to research conducted at the Johns Hopkins Children’s Center and elsewhere.
The findings from a multicenter trial were presented at the annual meeting of the American Academy of Allergy, Asthma & Immunology, held Feb. 26 to March 2 in New Orleans.
Previous research at Johns Hopkins showed that the same approach, known as oral immunotherapy, can be used successfully to treat children with milk allergies. Some of the children in the milk allergy study overcame their condition completely, and many experienced less severe allergic symptoms as a result of the therapy.
Now, researchers are reporting similarly encouraging results in children with egg allergies.
“Just as we saw in our patients with milk allergies before, oral immunotherapy for children with egg allergies works in the same way by slowly retraining the immune system to tolerate the allergens that caused allergic reactions,” said study investigator Robert Wood, director of Allergy and Immunology at the Johns Hopkins Children’s Center.
Researchers caution that confirming these early results requires long-term monitoring of the current patients and enrolling more children in the ongoing trials. They also caution that oral immunotherapy should be implemented only by a trained pediatric allergist.
In the 11-month study of 45 children ages 5 to 18, researchers gave 40 patients increasingly higher doses of egg whites during multiple food challenges conducted in a clinic and under a doctor’s supervision, while 15 children received a placebo, “dummy” food that looks like egg whites but contains no egg protein. All children received higher and higher doses of either placebo or actual egg protein in the course of the 11 months.
At the end of the study, during a final food challenge, more than half the children who had been consuming eggs (21 out of 40) could tolerate 5 grams of eggs without having an allergic reaction; none of the children who received placebo were able to tolerate eggs.
When symptoms did occur, investigators say, they were mild to moderate and involved mostly itching and swelling of the mouth and throat.
Children who consumed eggs also had lower blood levels of IgE antibodies—immune markers that rise during an allergic reaction—and a significant drop in the levels of egg-specific basophils, a type of white blood cell that multiplies during an allergic reaction.
Food allergies have been steadily rising in the last decade and are becoming harder to outgrow, research shows. An estimated 2 percent to 3 percent of U.S. children have egg allergies.
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