Food specific oral immunotherapy: a potential treatment for food allergy

Abstract

Food allergy is a potentially life-threatening condition affecting up to 8% of children and up to 2% of adults in westernized countries. There are currently no approved treatments for food allergy apart from avoidance. The apparent increase in incidence of food allergies over the past few decades calls attention to the need for effective, disease-modifying therapies for food allergies. Oral immunotherapy (OIT) is a promising experimental treatment in which food allergic patients consume increasing quantities of food in attempt to increase their threshold for allergic reaction. Studies are ongoing to determine whether OIT is capable of safely inducing not only desensitization but also tolerance to the allergenic foods. This article focuses on recent relevant studies of OIT for the treatment of common food allergies.

Keywords:

• desensitization
• double blind placebo-controlled food challenge
• food allergy
• omalizumab
• oral immunotherapy
• probiotic
• sustained unresponsiveness
• tolerance

Financial & competing interests disclosure

W Burks has consulting agreements with the following commercial entities; Allertein, Dynavax Technologies Corp, GLG Research, Mastcell Pharmaceuticals, Inc., Perrigo Company, Regeneron Pharmaceuticals, Inc., Perosphere, Inc., ActoGeniX, SRA lnternational, Genetech, Valeant Pharmaceuticals, and Sanofi US Services. W. Burks serves on the boards of FARE and the World Allergy Organization and has research sponsored by Hycor Biomedical and the Allergen Research Corp. W Burks also holds a faculty appointment at The University of North Carolina at Chapel Hill. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Key issues

• There are currently no approved treatments for food allergy.

• A number of studies of oral immunotherapy (OIT) for the treatment of milk, egg and peanut allergies have demonstrated the ability to induce desensitization.

• There is limited data on the ability of OIT to induce long-term tolerance to foods and warrants further study.

• Studies show varying results in terms of changes in immunologic parameters during OIT. Changes in food-specific SPT and IgE, Th2-cytokines production and food-specific T-regulatory cell numbers vary, but a rise in food-specific IgG4 is seen consistently across studies.

• Adverse effects are common and highlight the importance of escalating doses of OIT in a controlled setting where patients can be treated immediately for life-threatening allergic reactions.

• Alteration of allergenic milk or egg proteins through extensive heating may accelerate the process of achieving natural tolerance to milk or egg. Tolerance of heated forms of milk or egg may define a separate, milder phenotype of milk or egg allergy.

• Anti-IgE therapies may be effective for increasing safety and effectiveness of OIT.

• Long-term safety of OIT is not known. Approximately 10–20% of subjects will experience GI side effects, and cofactors such as viral infections and exercise may increase the likelihood of accidental allergic reactions to OIT dosing

• For these reasons, OIT is not recommended for use in clinic practice as of yet. Further studies are needed to determine the effectiveness and improve safety of OIT as a treatment for food allergy.