Sustained unresponsiveness after baked egg therapy compared with egg OIT
Published online: June 11, 2020
Egg allergy remains one of the most common food allergies in children. While the majority are expected to outgrow egg allergy, the allergy and the risk of severe allergic reactions can remain for many years, even lasting into adulthood for 20% of patients. Many egg-allergic patients can safely eat extensively heated or “baked egg” products such as muffins and cakes while still being reactive to less cooked forms of egg such as scrambled eggs, fried eggs, French toast or custards. Eating baked egg foods regularly has been thought to possibly speed up the process of outgrowing egg allergy.
The CoFAR7 study, conducted by the NIH-sponsored Consortium for Food Allergy Research and published by Kim et al in The Journal of Allergy and Clinical Immunology (JACI), recruited egg-allergic patients ages 3 to 16 years of age who could safely eat baked egg, but had allergic symptoms to egg white powder during oral food challenge. The participants were divided between two groups to either be treated with baked egg or egg oral immunotherapy (OIT). A third group of participants was recruited as a comparison and included participants who were reactive to baked egg and treated with egg OIT. After two years of treatment, a food challenge to ~1 egg (7444 mg egg white protein) was performed to show desensitization followed by a second identical food challenge 8-10 weeks after stopping treatment to show persistent desensitization also known as sustained unresponsiveness (SU).
Of the 52 baked-egg tolerant participants (median age 7.7 years), 28 were treated with baked egg and 24 were treated with egg OIT. The third group included 40 baked egg reactive participants treated with egg OIT. During the year 2 food challenge, 14.8% of baked egg treated participants were fully desensitized compared to 78.3% of egg OIT treated participants. Only 11.1% of baked egg treated participants showed SU compared to 43.5% of egg OIT treated participants 8-10 weeks after stopping treatment. Despite also receiving egg OIT, response was weaker in the baked egg reactive group with 56.4% desensitized and 17.9% showing SU. Biomarkers including egg white IgE, IgG4 and skin prick testing changed with therapy showing protective effects on the allergic immune response. These immune changes were stronger after egg OIT compared with baked egg. Dosing symptoms were uncommon and mostly mild in both groups of baked egg tolerant participants while far more symptoms were reported in the baked egg reactive participants receiving egg OIT.
Baked egg containing foods are tolerated by most egg-allergic patients and appears generally safe when used as a potential treatment. However, only a low number of egg-allergic participants showed SU after baked egg therapy suggesting a smaller treatment effect than previously thought. With its good safety and the stronger SU effect seen in the current study, egg OIT may be a treatment consideration for a subset of baked egg tolerant participants.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.