Eosinophilic esophagitis as a complication of food oral immunotherapy

Oral Immunotherapy: An Overview

Oral immunotherapy (OIT) is an alternative treatment of IgE-mediated food allergy that has been shown to increase tolerance threshold to many of the top food allergens, although this effect may be dependent on age, dose, frequency, and duration. OIT has been shown to be effective and safe in infants, and early initiation can improve rates of desensitization even for those foods whose natural history favors loss of allergy. Studies looking at protocol modification to improve OIT success are ongoing as is the evaluation of clinical tools to help monitor OIT effects.

Eosinophil-Associated Gastrointestinal Manifestations During OIT

Gastrointestinal adverse events are common during oral immunotherapy (OIT) for food allergy and range from immediate IgE-mediated reactions to non-anaphylactic clinical presentations. This review aims to summarize recent findings on non-anaphylactic eosinophil-associated gastrointestinal adverse events during OIT. Two clinical presentations of non-anaphylactic eosinophil-associated gastrointestinal adverse events during OIT are identified, each with a different paradigm for treatment, and distinguished by their time of onset. In the first clinical entity, characterized by its onset early in the course of treatment, patients present with abdominal pain, nausea, and/or vomiting. The symptoms become evident typically within weeks to months of starting OIT. These symptoms, however, are not temporally related to the time of dose administration, as in the case of immediate IgE-mediated anaphylactic reactions. While esophageal biopsies, when performed, can demonstrate eosinophilic esophagitis (EoE), baseline esophageal eosinophilia has also been observed in food allergic patients prior to OIT. A potential non-invasive biomarker, the peripheral absolute eosinophil count (AEC), often rises during these reactions and subsides after dose reduction and subsequent resolution of symptoms. OIT can usually then be resumed, albeit at a slower pace, without a recurrence of symptoms. Risk factors for development of symptoms early during OIT include a high starting dose and a baseline AEC of greater than 600. The second, and much less frequently encountered, non-anaphylactic gastrointestinal adverse event related to OIT, presents months to years after initiating OIT. In this latter group, patients present with the classical clinical symptoms and endoscopic findings of EoE. In contrast to the acute onset group, peripheral eosinophilia is usually not observed in these cases. This OIT-associated EoE has shown good response to standard EoE treatment approaches of proton pump inhibitors or swallowed steroids. Most patients with eosinophil-associated adverse reactions are able to continue OIT and remain desensitized. Treatment approaches depend on the specific subtype of these reactions and relate to the stages of OIT treatment.

Efficacy and safety of oral immunotherapy for peanut, cow's milk, and hen's egg allergy: A systematic review of randomized controlled trials

BACKGROUND

Oral immunotherapy (OIT) is a promising treatment for food allergies; however, safety is a concern. We synthesized evidence from the best randomized controlled trials (RCTs) on efficacy/safety of OIT for desensitization (DS) and remission (sustained unresponsiveness (SU)) in IgE mediated allergy to peanut, hen's eggs, and cow's milk. BODY: We searched Pubmed, EMBASE, and Cochrane databases (Until Oct 22) identifying 16 eligible RCTs published in English measuring food allergy by food challenge at the beginning and at the end of the study. The Cochrane Risk of Bias tool was used to assess study quality. We found 18 eligible studies. There was evidence of efficacy for DS for all allergens: peanut (RR 11.32; 95% CI 5.93, 21.60, I² 49%, 8 studies); hen's egg (RR 4.67; 2.66, 8.21, I² 0%, 5 studies); cow's milk (RR 13.98; 3.51, 55.65, I² 0%, 4 studies) and evidence for SU for peanut (RR 7.74; 2.90, 20.69, I² 0%, 3 studies) and hen's egg (RR 6.91; 1.67, 28.57, I² 0%, 2 studies). Allergic events were increased with intervention, and risk of adrenaline use increased for peanut RR 2.96; 1.63, 5.35, I² 0%, 8 studies; egg RR 1.71; 0.42, 6.92, I² 0%, 6 studies; and milk RR 8.45; 2.02, 35.27, I² 0%, 4 studies.

CONCLUSION

We found strong evidence that peanut, hen's egg, and cow's milk OIT can induce DS and some evidence for remission. There was a high risk of allergic reactions. Generalizability to the entire food allergic population is not known.

Oral immunotherapy for food allergy: Translation from studies to clinical practice?

Oral immunotherapy (OIT) is now recognized as an alternative active treatment to strict food avoidance in certain patients with IgE-mediated food allergy. Studies have confirmed the efficacy of OIT to desensitize children with allergy to cow's milk, eggs, and peanuts. The benefits, risks, and constraints of OIT are becoming increasingly well understood. However, there is no consensual criteria to select patients to whom OIT could be proposed, and many issues remain to address including the definitions of desensitization and long-term efficacy, the assessment of patient's experience in real life, the optimization of buildup and maintenance protocols, and the utility of multiple food OIT. The recent authorization by medical agency concerning the first medicine for peanut OIT is a step forward towards higher standardization in the practice of OIT. This article summarizes in comprehensive narrative format data on efficacy, tolerance, impact on quality of life and adverse effects of OIT and discuss elements to consider in clinical practice before starting OIT.

Oral Immunotherapy

Oral immunotherapy (OIT) is an alternative treatment of IgE-mediated food allergy that has been shown to increase tolerance threshold to many of the top food allergens, although this effect may be dependent on age, dose, frequency, and duration. OIT has been shown to be effective and safe in infants, and early initiation can improve rates of desensitization even for those foods whose natural history favors loss of allergy. Studies looking at protocol modification to improve OIT success are ongoing as is the evaluation of clinical tools to help monitor OIT effects.

Oral Immunotherapy and Risk of Eosinophilic Esophagitis in Children: 15 Years' Experience

OBJECTIVES

Oral immunotherapy (OIT) is an effective treatment for children with persistent food allergy, and has concerns about its safety, including eosinophilic esophagitis (EoE). The aim of this study was to evaluate the prevalence of EoE in a large cohort of children who underwent OIT in our center, and to determine if there were any clinical, endoscopic, or histologic differences depending on the food employed for the OIT.

METHODS

A retrospective study was performed over a 15-year period (2005-2020). Children who underwent cow's milk (CM), egg, and/or peanut OIT and developed EoE were included.

RESULTS

Six hundred and seven OIT were carried out (277 CM-OIT, 322 egg-OIT, and 8 peanut-OIT). Seventeen patients (2.8%) had a confirmed histologic diagnosis of EoE with a higher prevalence for patients who underwent CM-OIT (3.9%) than egg-OIT (2.2%). Symptoms suggestive of EoE and a confirmed diagnosis occurred at median times of 25 and 36 months, respectively, after the build-up phase of the OIT was completed. Choking, abdominal pain, and dysphagia were the most frequent symptoms and lamina propria fibrosis was observed in 41.2% of patients. No significant differences in clinical symptoms, endoscopic, or histologic findings between patients under CM or egg-OIT were found. One-third of patients reported mild symptoms suggestive of EoE before the OIT.

CONCLUSIONS

EoE appears to be a rare but important adverse event that can occur even years after OIT. Validated questionnaires to screen EoE before the OIT and in the follow-up of these patients may be the main tool for an early diagnosis.

Breaking down the complex pathophysiology of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic and progressive immune-mediated disease of the esophagus associated with antigen-driven type 2 inflammation and symptoms of esophageal dysfunction. Our understanding of EoE pathophysiology has evolved since its initial recognition more than 20 years ago and has translated into diagnostic and novel therapeutic approaches that are affecting patient care. The mechanisms underlying disease development and progression are influenced by diverse factors, such as genetics, age, allergic comorbidities, and allergen exposures. Central to EoE pathophysiology is a dysregulated feed-forward cycle that develops between the esophageal epithelium and the immune system. Allergen-induced, type 2-biased immune activation by the esophageal epithelium propagates a cycle of impaired mucosal barrier integrity and allergic inflammation, eventually leading to tissue remodeling and progressive organ dysfunction. Herein, we review the current understanding of fundamental pathophysiological mechanisms contributing to EoE pathogenesis.

Oral Immunotherapy in Food Allergy: A Critical Pediatric Perspective

There is evidence that in children with persistent IgE-mediated food allergy (FA) to cow's milk, hen's egg, and peanut, oral allergen-specific immunotherapy (OIT) may increase the reaction threshold to the culprit food allergen(s). OIT may protect patients from the occurrence of severe reactions in case of accidental ingestion of the culprit food during treatment. Notwithstanding, many gaps are still unsolved, including safety issues, identification of predictive biomarkers, and post-desensitization efficacy. In this perspective, the use of omalizumab (Anti-IgE monoclonal antibody) has been proposed as an adjunctive treatment to OIT in order to reduce the risk of allergic reactions related to OIT. This review aims to summarize the current evidence and unmet needs on OIT in children with FA to enhance the development of longitudinal, prospective, and well-designed studies able to fill the current gaps soon.

Management of Eosinophilic Esophagitis During Oral Immunotherapy

Food allergies are antigen-driven diseases that can lead to IgE-mediated reactions of immediate hypersensitivity (eg, anaphylaxis triggered by a single food) or non-IgE reactions of delayed hypersensitivity such as eosinophilic esophagitis (eg, inability to eat multiple foods manifesting as abdominal pain, choking, dysphagia, vomiting, reflux, food impaction). Although both types of disease have their own unique set of challenges in diagnosis and management, it is a particularly vexing problem when a patient is afflicted by both conditions. This situation can happen when individuals with IgE-mediated food allergy undergo desensitization using currently available forms of oral immunotherapy. In this Grand Rounds Review, we review diagnostic approaches to oral immunotherapy-associated eosinophilic esophagitis, potential relationships between primary and secondary eosinophilic esophagitis, potential management approaches, areas of uncertainty, and upcoming research. Optimally supporting patients in their journey with food allergy requires shared decision making regarding alternative management strategies and the stimulation of robust research.

Wheat oral immunotherapy

PURPOSE OF REVIEW

The prevalence of food allergy is increasing on a global scale, and therefore increased attention is being paid to specific food allergy epidemiology and management. There has been a large amount of progress made in the last decade on human trials of wheat oral immunotherapy (WOIT).

RECENT FINDINGS

To date, there has been one multicenter, double-blind, randomized controlled trial of WOIT, one randomized, noncontrolled trial of WOIT, and several smaller, nonrandomized clinical trials of WOIT. WOIT trials are generally limited by smaller sample sizes, affecting the demographic skew of evaluated patients. In addition, there is minimal standardization of efficacy and safety outcomes between trial protocols, making head-to-head comparison challenging. However, some common themes emerge. The majority of WOIT regimens result in successful desensitization, and success is more likely with higher maintenance dosing for longer periods of time. Limited studies have looked at sustained unresponsiveness in WOIT. WOIT can induce allergic reactions, including anaphylaxis, but more severe reactions often have an associated augmenting factor, such as exercise. Lower maintenance doses likely are associated with less severe reactions, and food modification and/or adjunct therapeutics may also decrease the risk of reactions.

SUMMARY

WOIT trials are ongoing and will optimize updosing protocols and maintenance doses to improve efficacy and safety.