Heat-Denatured Egg Allergens May Offer Safer Oral Immunotherapy

Heat-denatured egg allergens may offer a safer starting point for oral immunotherapy in egg-allergic patients, according to new data showing reduced IgE binding and blunted basophil activation.1

“Heat-denaturation has long been considered a method to reduce allergen IgE binding and therefore make them less likely to trigger severe allergic responses,” wrote study investigator Marta Paolucci, PhD, from the University of Zurich, and colleagues.1 “Indeed, approximately 75% of children with milk or egg allergy tolerate heated or baked milk and egg products, suggesting that heating can modify protein structures and thereby alter the allergenicity of allergens. Our findings reinforce this concept, showing that heat-induced structural changes in these allergens can significantly reduce their ability to bind to IgE and can have a functional consequence on basophil activation.”

Oral immunotherapy is an emerging strategy for IgE-mediated food allergies, yet safety concerns, particularly systemic reactions during dose escalation, have limited widespread adoption. Due to potential reactions, dietary avoidance remains the primary management for food allergies.2

Investigators assessed whether heat-induced structural changes in the major egg allergens, Gal d 1 and Gal d 2, could reduce their immunogenicity. 1By examining basophil activation in a cohort of 42 egg-allergic patients, the team examined whether heat-denatured allergens could serve as a safer alternative to native proteins in OIT protocols.1

Participants were recruited from 3 centers in Switzerland: Children's Hospital Zurich (KISPI), Kantonsspital Baden (KSB), and University Hospital Zurich (USZ). Children were included if they had an allergist-confirmed oral or systemic reactivity to egg-containing foods based on a consistent clinical history of reactions to cooked, baked, scrambled, or raw egg. Adults were included if they had a documented history of reactions to egg-containing foods and a positive skin prick test.1

Investigators obtained peripheral blood samples, determined patients’ sensitization status, and isolated and incubated basophils with native or heat-denatured egg allergen preparations. The team assessed basophil activation by measuring leukotriene release as a marker of degranulation.

Egg proteins were heat-denatured by diluting purified Gal d 1 (ovomucoid, LoTox natural Gal d 1, LTN-GD1-1, InBio, Charlottesville) and natural Gal d 2 (ovalbumin, LoTox natural Gal d 2, LTN-GD2-1, InBio) to 1 mg/mL in 1.5 mL Eppendorf tubes. Samples were heated at 20°C–100°C for 10 minutes to 6 hours using a water bath or thermo-shaker, then chilled in an ice bath for 1 minute to halt denaturation. Both heat-denatured and native controls were stored at 4°C until use in the study.

The study exposed Gal d 1 and Gal d 2 to heat treatments of varying temperature and duration, confirming structural alterations via SDS-PAGE, ELISA, NanoDSF, and circular dichroism. Functional assays showed that heat-denatured allergens triggered significantly lower basophil degranulation than their native counterparts, though individual responses varied with patients’ IgE sensitization profiles.1

The analysis also demonstrated that heat-denaturation reduced IgE binding across the cohort, with time- and temperature-dependent effects on allergen structure. Among patients who still reacted to heat-denatured allergens, baseline egg-white IgE levels were greater, yet these patients required increased allergen doses to elicit leukotriene release. Overall, greater doses of heat-denatured allergens were necessary to trigger basophil activation compared with native allergens, indicating a measurable decrease in allergenic potency.1

These results provide a mechanistic explanation for the lower allergenicity of baked or heat-processed eggs and support their potential integration into OIT regimens. Heat-denatured allergens could allow clinicians to initiate therapy with reduced risk of systemic reactions, particularly in patients with moderate IgE sensitization, while enabling dose escalation under controlled conditions.

The reduced basophil activation and IgE binding highlight the potential for safer, stepwise desensitization protocols. Investigators noted that future clinical trials are warranted to translate these molecular findings into practical OIT guidelines.

“Our findings contribute to the understanding of how thermal processing reduces allergenicity, supporting the development of safer food products and informing dietary management strategies for patients with egg allergy,” investigators wrote. “The work is highly relevant to clinicians, allergists, and food scientists as it bridges molecular allergology and practical implications for allergy diagnosis, food manufacturing, and immunotherapy approaches.”1

References

1. Paolucci M, Breiding M, Dietrich M, et al. Heat-treated egg allergens show lower basophil activation: A path toward safer oral immunotherapy. Pediatr Allergy Immunol. 2026;37(1):e70275. doi:10.1111/pai.70275

2. Muraro A, de Silva D, Halken S, et al. Managing food allergy: GA2LEN guideline 2022. World Allergy Organ J. 2022;15(9):100687. Published 2022 Sep 7. doi:10.1016/j.waojou.2022.100687