Immunotherapy for food allergy: Promise and progress
Allergen-specific immunotherapy, although still experimental, is becoming an area of active research for treatment of food allergy in children.
Food allergy is a life-altering and potentially life-threatening condition affecting millions of children in the United States. Recent reports place the prevalence of food allergy in the pediatric population at about 8%, but also provide evidence that it is becoming increasingly more common.1,2 Its seriousness is highlighted in part by data showing food allergy to be the most common cause of fatal and recurring anaphylaxis in children and adolescents.3 Living with constant fear of accidental ingestion and its potential sequelae, it is not surprising that patients with food allergy and their families experience a tremendous psychosocial and quality-of-life burden.4
The standard of care for food allergy involves nutritional counseling, allergen avoidance, and the ready availability of injectable epinephrine to treat acute reactions arising from accidental allergen exposure. Clearly, however, better options are needed, and allergen-specific immunotherapy (SIT) for food allergy is an area of active research.
With SIT, patients are exposed to escalating doses of the culprit allergen(s) in order to induce desensitization and, ideally, tolerance. Although SIT is considered as safe and effective for managing patients with allergic asthma, allergic rhinoconjunctivitis, and stinging insect allergies,5 its use for food allergy is still experimental.6,7
Research with SIT for food allergy has been conducted investigating epicutaneous, sublingual, and oral routes of allergen administration. Of these approaches, oral immunotherapy (OIT) is generating particular excitement.
Multiple groups have published research on their experience with OIT for the most common food allergens, including cow’s milk, egg, peanut, and tree nuts. Using various protocols for allergen dose escalation, OIT investigators have reported achieving desensitization rates ranging from about 45% to 75%.8 In addition, studies exposing individuals to an oral food challenge at intervals of time after stopping OIT provide evidence that some individuals (25% to 40%) develop tolerance to the inciting antigen, at least in the short term.9
With dose escalation carried out in a controlled and supervised setting, OIT also has been reasonably safe.6,9 However, safety remains a concern because treatment-related adverse events are common and have included severe reactions requiring epinephrine injection along with reports of the development of eosinophilic gastrointestinal disorders.6,8
Therefore, experts agree there is much work yet to be done before OIT is ready to be used as a routine clinical treatment for patients with food allergies. Desensitization protocols need to be refined and then demonstrated safe and effective in multicenter, randomized, controlled clinical trials. In addition, more information is needed on the risk of resensitization, and there is interest in identifying biomarkers as potential predictors of desensitization responses and the development of tolerance.