The research supported by the National Institutes of Health that included staff from the University of Arkansas for Medical Sciences (UAMS) and the Arkansas Children's Hospital Research Institute (ACHRI) has found that daily doses of egg white powder may one day enable some children and adolescents with egg allergy to eat egg-containing foods without having allergic reactions.
Researchers were encouraged by promising results when children with egg allergy were given small but increasing daily doses of egg white powder. Many of the study participants who received the doses were later able to eat egg-containing substances without suffering an allergic reaction. In a few cases, children even appeared to have outgrown the egg allergy weeks after the daily doses were stopped.
The study results will appear in today's issue of the New England Journal of Medicine.
"These are very exciting findings in what is the largest food allergy study for egg allergy to date - showing that some children with egg allergy receiving oral immunotherapy were protected from allergic reactions or even appeared to outgrow the allergy," said Stacie M. Jones, M.D., professor of pediatrics in the UAMS College of Medicine and chief of the Pediatric Allergy and Immunology Section, a lead author of the study.
"This study, involving 55 children, was conducted in five centers in the United States and still represents a small population of egg-allergic kids, but the results are very promising," said Jones, who conducts research and treats patients at Arkansas Children's Hospital.
Jones, who holds the Dr. and Mrs. Leeman King Chair in Pediatric Allergy, noted that as of now the only way to prevent egg allergy reactions is to avoid foods that contain eggs.
The study is one of several federally funded trials of new forms of immunotherapy to treat food allergy. Oral immunotherapy is 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 oral immunotherapy carries some risk for allergic reactions, these studies are all conducted under the guidance of trained clinicians and research teams.
Symptoms of allergic reactions to foods 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).
"We need to interpret these findings cautiously because we still have a lot to learn about the mechanisms of desensitization, optimal dosing and long-term tolerance," said Amy Scurlock, M.D., an associate professor of pediatrics in the UAMS College of Medicine and researcher at ACHRI.
"This is a promising development and could help the parents and children for whom an egg allergy is a life-changing diagnosis that carries psychological, social and economic implications," Scurlock said.
The results are the latest findings from the Consortium of Food Allergy Research (CoFAR), a network established by NIAID to conduct clinical trials, observational studies and basic research to better understand and treat food allergy. The trial was conducted at clinical sites in Baltimore; Chapel Hill, N.C.; Denver; Little Rock, Ark.; and New York City.
The goals of the study were to determine if daily egg oral immunotherapy 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 CoFAR study enrolled 55 children and adolescents ages 5 to 18 who had egg allergy, one of the most common food allergies seen in children. Participants were randomly assigned either to the treatment group, which received egg oral immunotherapy (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. Researchers gradually increased the dose of egg or placebo powder every two weeks until the children in the egg oral immunotherapy 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. They passed the challenge if they had either no symptoms or only transient symptoms not directly observable by a doctor, such as throat discomfort. Participants failed the challenge if they had symptoms that could be observed by a doctor.
After 10 months, none of the participants who received placebo passed the challenge, but 55 percent of those on egg oral immunotherapy did. After 22 months of egg oral immunotherapy, researchers gave a second oral food challenge to all of the children in the treatment group. At this food challenge, 75 percent of those on egg oral immunotherapy passed.
To determine if egg oral immunotherapy 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 oral immunotherapy for four to six weeks and then rechallenged at 24 months. Eleven of the original 40 children (about 27 percent) 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 oral immunotherapy. Second, a small group of children--approximately one-fourth--were able to eat egg in their regular diets even after stopping oral immunotherapy for four to six weeks.
"Reducing these kids' allergic response to egg also lessened parental anxiety over how their children might react if accidently exposed to egg at school or at someone else's house," Jones said.
Jones said the next step would be a larger study and more specific examinations of dosing and timing of oral immunotherapy, as well as further study of the safety of this new therapy.
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