Even though about 70 percent of children with egg allergies – one of the most common food allergies – outgrow the condition, the mechanism by which children develop a tolerance has remained undiscovered.
In a recent study, however, Northwestern Medicine scientists found that children who develop a natural tolerance to egg protein start producing more of cytokine interleukin-10 (IL-10), an anti-inflammatory protein.
“The fundamental question is how do children outgrow their food allergies, and our field has failed to answer that question,” said Anna B. Fishbein, MD, assistant professor in Pediatrics-Allergy and Immunology, and first author of the study. “We sought to understand how kids develop tolerance naturally.”
The paper, recently published in Annals of Allergy, Asthma and Immunology, was the first to address the mechanisms of natural tolerance to food allergy using cytokine responses.
Dr. Fishbein isolated white blood cells from children with egg protein allergies, without allergies and those who have recently outgrown their allergies. In a petri dish, she stimulated white blood cells with egg and observed the response of the cells by measuring levels of different cytokines. They found the children who developed tolerance to egg allergy had an increase in the production of the cytokine IL-10.
“The largest difference in cytokine levels was with IL-10. We saw an increase in the production of IL-10 in those children who outgrew their allergies in response to egg protein compared to allergic and non-allergic children,” Dr. Fishbein said. Dr. Fishbein also found that naturally tolerant children produced fewer amounts of two other cytokines that regulate allergic response, IL-4 and IL-5, than patients with an allergy.
The increase in IL-10 and decrease in IL-4 and IL-5 suggests that the cells regulating these cytokines might play an important role in the development of tolerance naturally.
“The next part of the work is looking at what cells are making IL-10 in these children who out grow their allergy and conducting similar studies with other food allergens,” said Ramsay Fuleihan, MD, professor in Pediatrics-Allergy and Immunology and senior author on the paper. “This research has significant implications for developing treatments of food allergy.”
This research was support by the Gerber Foundation, the Children’s Hospital of Chicago Faculty Practice Plan and the Bunning Food Allergy Initiative.