Primary eosinophilic gastrointestinal disorders in children who have received food oral immunotherapy

Proton pump inhibitors in eosinophilic esophagitis (EoE) related to oral immunotherapy: is it as effective as in other EoE?

Oral immunotherapy (OIT) may induce eosinophilic esophagitis (EoE). Proton pump inhibitors (PPIs) are an effective treatment for EoE. However, the effect of PPI treatment is not well established in patients with EoE induced by OIT. Our primary aim was to compare the clinical, endoscopic, and histological response rates to PPIs in children with EoE induced by OIT (EoE+OIT) versus EoE patients without OIT (EoE-OIT). The secondary aims are to describe the clinical and histological features of EoE+OIT. Demographic, clinical, endoscopic, and histological findings of patients with EoE in the gastroenterology clinic at Shamir Medical Center between March 2015 and December 2022 were collected. Comparisons were performed between EoE+OIT and EoE-OIT patients. The study included 42 children (74% male, mean age 11.2), of whom 31 had EoE-OIT and 11 had EoE+OIT. There were no significant differences between groups regarding sex, comorbidities, symptoms, or endoscopic and histological characteristics at diagnosis. All 42 children were treated with PPIs after diagnosis with or without diet changes. The rates of any clinical response were 83.9% and 90.1% in the EoE-OIT group and EoE+OIT group, respectively (p = 1.0). The rate of any endoscopic response was 74.2% for EoE-OIT and 81.8% for EoE+OIT (p = 0.54). Histologically, PPIs were even more effective in the EoE+OIT group, where only 18.2% had no histological response at all compared to 51.6% in the EoE-OIT group (p = 0.1).

CONCLUSION

PPI treatment is as effective in EoE with OIT as it is in EoE due to other etiologies.

WHAT IS KNOWN

• Proton pump inhibitor (PPI) treatment is effective for achieving clinical response and histologic remission in some patients with eosinophilic esophagitis (EoE). • EoE has also been reported to be triggered by oral immunotherapy (OIT).

WHAT IS NEW

• PPI treatment in EoE with OIT is as effective as treatment for EoE due to other etiologies.

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.

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.

How We Manage Gastrointestinal Symptoms During Oral Immunotherapy Through a Shared Decision-Making Process-A Practical Guide for the Community Practitioner

Allergists addressing gastrointestinal (GI) symptoms during oral immunotherapy (OIT) may be biased toward diagnoses related to OIT; however, non-OIT causes may occur. Although there is currently a lack of robust data for evidence-based treatment recommendations, we provide 3 real-world illustrative cases along with a proposed management algorithm for GI symptoms encountered during OIT. This algorithm was developed because of a significant clinical need, given the number of new-to-OIT providers that include practicing allergists, trainees transitioning into practice, and allied health care providers who manage GI symptoms in OIT patients. We developed the algorithm based on the opinions of community and academic allergy clinics across Canada with significant clinical experience offering infant, preschool, and school-aged OIT patients, with gastroenterologist input. Further research is needed to fill the knowledge gaps in the management of GI symptoms during OIT before formal recommendations can be suggested.

Single-dose AAV vector gene immunotherapy to treat food allergy

Immunotherapies for patients with food allergy have shown some success in limiting allergic responses. However, these approaches require lengthy protocols with repeated allergen dosing and patients can relapse following discontinuation of treatment. The purpose of this study was to test if a single dose of an adeno-associated virus (AAV) vector can safely prevent and treat egg allergy in a mouse model. AAV vectors expressing ovalbumin (OVA) under an ubiquitous or liver-specific promoter were injected prior to or after epicutaneous sensitization with OVA. Mice treated with either AAV8-OVA vector were completely protected from allergy sensitization. These animals had a significant reduction in anaphylaxis mediated by a reduction in OVA-specific IgE titers. In mice with established OVA allergy, allergic responses were mitigated only in mice treated with an AAV8-OVA vector expressing OVA from an ubiquitous promoter. In conclusion, an AAV vector with a liver-specific promoter was more effective for allergy prevention, but higher OVA levels were necessary for reducing symptoms in preexisting allergy. Overall, our AAV gene immunotherapy resulted in an expansion of OVA-specific FoxP3⁺ CD4⁺ T cells, an increase in the regulatory cytokine IL-10, and a reduction in the IgE promoting cytokine IL-13.

World Allergy Organization (WAO) Diagnosis and Rationale for Action against Cow's Milk Allergy (DRACMA) guideline update - XIII - Oral immunotherapy for CMA - Systematic review

Background

Allergy to cow's milk is the most common food allergy in infants and it is usually outgrown by 5 years of age. In some individuals it persists beyond early childhood. Oral immunotherapy (OIT, oral desensitization, specific oral tolerance induction) has been proposed as a promising therapeutic strategy for persistent IgE-mediated cow's milk allergy. We previously published the systematic review of OIT for cow's milk allergy (CMA) in 2010 as part of the World Allergy Organization (WAO) Diagnosis and Rationale for Action against Cow's Milk Allergy (DRACMA) Guidelines.

Objective

To systematically synthesize the currently available evidence about OIT for IgE-mediated CMA and to inform the updated 2022 WAO guidelines.

Methods

We searched the electronic databases including PubMed, Medline, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), and the websites of selected allergy organizations. We included all studies irrespective of the language of the original publication. The last search was conducted in February 2021. We registered the protocol on Open Science Framework (10.17605/OSF.IO/AH2DT).

Results

We identified 2147 unique records published between 2010 and 2021, including 13 randomized trials and 109 observational studies addressing cow's milk OIT. We found low-certainty evidence that OIT with unheated cow's milk, compared to elimination diet alone, increased the likelihood of being able to consume ≥150 ml of cow's milk in controlled settings (risk ratio (RR): 12.3, 95% CI: 5.9 to 26.0; risk difference (RD): 25 more per 100, 95% CI 11 to 56) as well as accidently ingest a small amount (≥5 ml) of cow's milk (RR: 8.7, 95% CI: 4.7 to 16.1; RD: 25 more per 100, 95% CI 12 to 50). However, 2–8 weeks after discontinuation of a successful OIT, tolerance of cow's milk persisted in only 36% (range: 20%–91%) of patients. OIT increased the frequency of anaphylaxis (rate ratio: 60.0, 95% CI 15 to 244; rate difference 5 more anaphylactic reactions per 1 person per year, 95% CI: 4 to 6; moderate evidence) and the frequency of epinephrine use (rate ratio: 35.2, 95% CI: 9 to 136.5; rate difference 268 more events per 100 person-years, 95% CI: 203 to 333; high certainty). OIT also increased the risk of gastrointestinal symptoms (RR 6.9, 95% CI 1.6–30.9; RD 28 more per 100, CI 3 to 100) and respiratory symptoms (RR 49.0, 95% CI 3.12–770.6; RD 77 more per 100, CI 62 to 92), compared with avoidance diet alone. Single-arm observational studies showed that on average 6.9% of OIT patients (95% CI: 3.8%–10%) developed eosinophilic esophagitis (very low certainty evidence). We found 1 trial and 2 small case series of OIT with baked milk.

Conclusions

Moderate certainty evidence shows that OIT with unheated cow's milk in patients with IgE-mediated CMA is associated with an increased probability of being able to drink milk and, at the same time, an increased risk of serious adverse effects.

Probiotic peanut oral immunotherapy versus oral immunotherapy and placebo in children with peanut allergy in Australia (PPOIT-003): a multicentre, randomised, phase 2b trial

BACKGROUND

Oral immunotherapy is effective at inducing desensitisation to allergens and induces sustained unresponsiveness (ie, clinical remission) in a subset of patients, but causes frequent reactions. We aimed to investigate whether addition of a probiotic adjuvant improved the efficacy or safety of peanut oral immunotherapy.

METHODS

PPOIT-003, a multicentre, randomised, phase 2b trial, was conducted in three tertiary hospitals in Australia (Adelaide [SA], Melbourne [VIC], and Perth [WA]) in children aged 1-10 years, weighing more than 7 kg, with peanut allergy confirmed by a double-blind placebo-controlled food challenge (cumulative 4950 mg dose of peanut protein) and positive peanut skin prick test (≥3 mm) or peanut-specific IgE (≥0·35 kU/L). Children were randomly assigned (2:2:1) to receive probiotic and peanut oral immunotherapy (PPOIT), placebo probiotic and peanut oral immunotherapy (OIT), or placebo probiotic and placebo OIT (placebo) for 18 months, and were followed up until 12 months after completion of treatment. Oral immunotherapy consisted of increasing doses of peanut protein (commercially available food-grade 12% defatted peanut flour [50% peanut protein]) until a 2000 mg daily maintenance dose was reached. The probiotic adjuvant was a daily dose of 2 × 10¹⁰ colony-forming units of the probiotic Lactobacillus rhamnosus ATCC 53103. Placebo immunotherapy comprised maltodextrin, brown food colouring, and peanut essence, and placebo probiotic was maltodextrin. Dual primary outcomes were 8-week sustained unresponsiveness, defined as no reaction to a cumulative dose of 4950 mg peanut protein at treatment completion and 8 weeks after treatment completion, in the PPOIT versus placebo groups and the PPOIT versus OIT groups, analysed by intention to treat. Safety endpoints were adverse events during the treatment phase, and peanut ingestion and reactions in the 12-month post-treatment period. This study is registered with the Australian New Zealand Clinical Trials Registry, 12616000322437.

FINDINGS

Between July 4, 2016, and Sept 21, 2020, 201 participants were enrolled and included in the intention-to-treat analysis. 36 (46%) of 79 children in the PPOIT group and 42 (51%) of 83 children in the OIT group achieved sustained unresponsiveness compared with two (5%) of 39 children in the placebo group (risk difference 40·44% [95% CI 27·46 to 53·42] for PPOIT vs placebo, p<0·0001), with no difference between PPOIT and OIT (-5·03% [-20·40 to 10·34], p=0·52). Treatment-related adverse events were reported in 72 (91%) of 79 children in the PPOIT group, 73 (88%) of 83 children in the OIT group, and 28 (72%) of 39 children in the placebo group. Exposure-adjusted incidence of adverse events was 10·58 in the PPOIT group, 11·36 in the OIT, and 2·09 in the placebo group (ratio 0·92 [95% CI 0·85 to 0·99] for PPOIT vs OIT, p=0·042; 4·98 [4·11-6·03] for PPOIT vs placebo, p<0·0001; 5·42 [4·48-6·56] for OIT vs placebo, p<0·0001), with differences seen primarily in gastrointestinal symptoms and in children aged 1-5 years. During the 12-month post-treatment period, 60 (85%) of 71 participants in the PPOIT group, 60 (86%) of 70 participants in the OIT group, and six (18%) of 34 participants in the placebo group were eating peanut; rescue epinephrine use was infrequent (two [3%] of 71 in the PPOIT group, four [6%] of 70 in the OIT group, and none in the placebo group).

INTERPRETATION

Both PPOIT and OIT were effective at inducing sustained unresponsiveness. Addition of a probiotic did not improve efficacy of OIT, but might offer a safety benefit compared with OIT alone, particularly in preschool children.

FUNDING

National Health and Medical Research Council Australia and Prota Therapeutics.

Advances, Practical Implementation, and Unmet Needs Regarding Oral Immunotherapy for Food Allergy

Treatment of food allergy is a rapidly changing landscape, with arguably, the most significant advancement in recent years, the transition of oral immunotherapy (OIT) to clinical practice. As an innovation, OIT is a phase of rapidly increasing demand, particularly for some allergens such as peanut, egg, and milk, which have substantial evidence of efficacy. However, significant questions remain about how to best treat multiple food allergies and less common food allergies and how to optimize long-term safety and efficacy. This review summarizes the currently available resources for integrating food allergy OIT into clinical practice and focuses on the multiple remaining unmet needs such as providing an approach for OIT to food allergens for which there is no or limited evidence; practical issues related to food allergy treatment particularly when it is not going well; long-term outcomes and follow-up after OIT; and strategies to help meet the impending increase in demand.

Efficacy and Safety of Baked Milk Oral Immunotherapy in Children with Severe Milk Allergy: A Randomized, Double-blind, Placebo-controlled Phase 2 Trial

BACKGROUND

Cow's milk allergy is the most common food allergy in young children and has no current treatment. Oral immunotherapy studies to date have shown efficacy but high rates of adverse reactions.

OBJECTIVE

We sought to evaluate the safety and efficacy of baked milk oral immunotherapy (BMOIT) in baked milk allergic children.

METHODS

Participants (3-18 years) were randomized to receive BMOIT or placebo for 12 months. Efficacy was assessed by double-blind placebo-controlled food challenge after 12 months of treatment. Safety, quality of life, and mechanistic parameters were also evaluated.

RESULTS

11/15 (73%) of the BMOIT participants reached the primary endpoint, tolerating 4044 mg of baked milk protein after 12 months of OIT, compared to 0/15 (0%) on placebo. The median maximal tolerated dose (MTD) and median change from baseline was significantly higher in the BMOIT group compared to placebo (median MTD 4044mg vs 144mg; p=0.001; median change in MTD of 3900mg vs 0mg, p=0.0001). Dose-related reactions were common but >95% in both groups were mild. There was no significant change in CM- or beta lactoglobulin-IgE from baseline for either group. CM-sIgG4 did significantly increase and casein IgE decreased in the BMOIT group. For proxy-reported food allergy quality of life, there was a significant difference in the emotional impact domain only with more improving while on placebo compared BMOIT. The majority of children and adolescents in the BMOIT group directly reported improvement in at least one domain.

CONCLUSION

BMOIT was well tolerated and induced a substantial level of desensitization after 12 months of treatment.

Oral Immunotherapy for Food-Allergic Children: A Pro-Con Debate

The prevalence of food allergy has increased in recent years, especially in children. Allergen avoidance, and drugs in case of an allergic reaction, remains the standard of care in food allergy. Nevertheless, increasing attention has been given to the possibility to treat food allergy, through immunotherapy, particularly oral immunotherapy (OIT). Several OIT protocols and clinical trials have been published. Most of them focus on children allergic to milk, egg, or peanut, although recent studies developed protocols for other foods, such as wheat and different nuts. OIT efficacy in randomized controlled trials is usually evaluated as the possibility for patients to achieve desensitization through the consumption of an increasing amount of a food allergen, while the issue of a possible long-term sustained unresponsiveness has not been completely addressed. Here, we evaluated current pediatric OIT knowledge, focusing on the results of clinical trials and current guidelines. Specifically, we wanted to highlight what is known in terms of OIT efficacy and effectiveness, safety, and impact on quality of life. For each aspect, we reported the pros and the cons, inferable from published literature. In conclusion, even though many protocols, reviews and meta-analysis have been published on this topic, pediatric OIT remains a controversial therapy and no definitive generalized conclusion may be drawn so far. It should be an option provided by specialized teams, when both patients and their families are prone to adhere to the proposed protocol. Efficacy, long-term effectiveness, possible role of adjuvant therapies, risk of severe reactions including anaphylaxis or eosinophilic esophagitis, and impact on the quality of life of both children and caregivers are all aspects that should be discussed before starting OIT. Future studies are needed to provide firm clinical and scientific evidence, which should also consider patient reported outcomes.

Eosinophilic gastrointestinal disorders and allergen immunotherapy: Lights and shadows

Allergic diseases, such as IgE-mediated food allergy, asthma, and allergic rhinitis, are relevant health problems worldwide and show an increasing prevalence. Therapies for food allergies are food avoidance and the prompt administration of intramuscular epinephrine in anaphylaxis occurring after accidental exposure. However, allergen immunotherapy (AIT) is being investigated as a new potential tool for treating severe food allergies. Effective oral immunotherapy (OIT) and epicutaneous immunotherapy (EPIT) induce desensitization and restore immune tolerance to the causal allergen. While immediate side effects are well known, the long-term effects of food AIT are still underestimated. In this regard, eosinophilic gastrointestinal disorders (EGIDs), mainly eosinophilic esophagitis, have been reported as putative complications of OIT for food allergy and sublingual immunotherapy (SLIT) for allergic asthma and rhinitis. Fortunately, these complications are usually reversible and the patient recovers after AIT discontinuation. This review summarizes current knowledge on the possible causative link between eosinophilic gastrointestinal disorders and AIT, highlighting recent evidence and controversies.

An Approach to the Office-Based Practice of Food Oral Immunotherapy

Oral immunotherapy (OIT) provides an active treatment option for patients with food allergies. OIT may improve quality of life and raise the threshold at which a patient with food allergy may react to an allergen, but it is a rigorous therapy that requires a high degree of commitment by the clinician, patients, and families. Recent guidelines from the Canadian Society for Allergy and Clinical Immunology have provided a framework for the ethical, evidence-based, and patient-oriented clinical practice of OIT, and the European Academy of Allergy, Asthma, and Immunology guidelines have also recommended that OIT can be used as a potential treatment. The recent Food and Drug Administration approval of an OIT pharmaceutical has accelerated the adoption of OIT. This review provides a summary of the recent Canadian Society for Allergy and Clinical Immunology guidelines and a consensus of practical experience of clinicians across the United States and Canada related to patient selection, office and staff preparation, the general OIT process, OIT-related reaction management, and treatment outcomes.

Eosinophilic Esophagitis as a Side Effect of Food Oral Immunotherapy

Food allergies (FAs) include a spectrum of immune-mediated serious and potentially life-threatening medical conditions with an overall estimated prevalence ranging from 4% to 8% in the U.S. and Europe. Significant progress in food allergen-specific immunotherapy has been accomplished over the past 10 years. The most studied strategy has been oral immunotherapy (OIT), also known as food desensitization, a treatment in which a child is slowly and deliberately given a small amount of the food to ingest (that previously was a food allergy trigger) with the ultimate goal of the child eating that food without a reaction. OIT is now recommended in the European guidelines for the treatment of milk, egg, and peanut allergies and was the first American Food Drug Administration (FDA) approved product for the prevention of severe reaction to peanuts in 4–17 year olds to be released on the market. The side effects associated with OIT treatment trials are mild to moderate, predominantly oropharyngeal, and easily treated. More severe reactions, such as generalized urticaria/angioedema, wheezing/respiratory distress, laryngeal edema, and repetitive emesis, have been reported. However systemic reactions are very rare. Low-dose immunotherapy is associated with significantly fewer side effects. Currently, its most limiting allergic side effect is that approximately 10–15% of subjects treated with OIT experience gastrointestinal symptoms, preventing the continuation of therapy. Eosinophilic esophagitis (EoE) has also been reported as a cause of persistent abdominal symptoms in OIT.

CSACI guidelines for the ethical, evidence-based and patient-oriented clinical practice of oral immunotherapy in IgE-mediated food allergy

Background

Oral immunotherapy (OIT) is an emerging approach to the treatment of patients with IgE-mediated food allergy and is in the process of transitioning to clinical practice.

Objective

To develop patient-oriented clinical practice guidelines on oral immunotherapy based on evidence and ethical imperatives for the provision of safe and efficient food allergy management.

Materials and methods

Recommendations were developed using a reflective patient-centered multicriteria approach including 22 criteria organized in five dimensions (clinical, populational, economic, organizational and sociopolitical). Data was obtained from: (1) a review of scientific and ethic literature; (2) consultations of allergists, other healthcare professionals (pediatricians, family physicians, nurses, registered dieticians, psychologists, peer supporters), patients and caregivers; and patient associations through structured consultative panels, interviews and on-line questionnaire; and (3) organizational and economic data from the milieu of care. All data was synthesized by criteria in a multicriteria deliberative guide that served as a platform for structured discussion and development of recommendations for each dimension, based on evidence, ethical imperatives and other considerations.

Results

The deliberative grid included 162 articles from the literature and media reviews and data from consultations involving 85 individuals. Thirty-eight (38) recommendations were made for the practice of oral immunotherapy for the treatment of IgE mediated food allergy, based on evidence and a diversity of ethical imperatives. All recommendations were aimed at fostering a context conducive to achieving objectives identified by patients and caregivers with food allergy. Notably, specific recommendations were developed to promote a culture of shared responsibility between patients and healthcare system, equity in access, patient empowerment, shared decision making and personalization of OIT protocols to reflect patients' needs. It also provides recommendations to optimize organization of care to generate capacity to meet demand according to patient choice, e.g. OIT or avoidance. These recommendations were made acknowledging the necessity of ensuring sustainability of the clinical offer in light of various economic considerations.

Conclusions

This innovative CPG methodology was guided by patients' perspectives, clinical evidence as well as ethical and other rationales. This allowed for the creation of a broad set of recommendations that chart optimal clinical practice and define the conditions required to bring about changes to food allergy care that will be sustainable, equitable and conducive to the well-being of all patients in need.

Efficacy of an elimination diet in a patient with eosinophilic gastroenteritis : a pediatric case with multiple food allergies

Eosinophilic gastrointestinal disorders are chronic inflammatory diseases in which eosinophils highly infiltrate into gastrointestinal tissue, resulting in gastrointestinal dysfunction. Here, we report a case of pediatric eosinophilic gastroenteritis (EGE). A 7-year-old boy with multiple food allergies (cow milk, hen's egg, fish,shellfish, and chicken) was admitted to our hospital because of continuous abdominal pain and vomiting. His soy allergy had been diagnosed to have oral tolerance based on an oral food challenge at the age of 6 years. He was diagnosed with EGE based on biopsy findings showing eosinophilic infiltration ( 20 eosinophils per high-power field) into the gastrointestinal mucosa. A diet eliminating soy, wheat, beef, pork, rice, and sesame in addition to the food that had already been eliminated and oral corticosteroids improved his symptoms and peripheral eosinophilia. A relapse of both abdominal pain and peripheral eosinophilia after the reintroduction of soy or pork identified them as foods causative of EGE. This report highlights the utility of elimination diets in improving EGE symptoms and the subsequent reintroduction of offending foods in identifying causative foods. Furthermore,EGE onset should be considered when introducing potentially allergic food in the management of food allergy. J. Med. Invest. 66 : 201-204, February, 2019.

Risk Factors and Treatment Outcomes for Oral Immunotherapy-Induced Gastrointestinal Symptoms and Eosinophilic Responses (OITIGER)

BACKGROUND

We recently described that oral immunotherapy (OIT)-induced gastrointestinal symptoms were associated with peripheral eosinophilic responses (termed OITIGER).

OBJECTIVE

To identify treatment outcomes after dose modification and risk factors for developing OITIGER.

METHODS

Treatment modifications in patients with OITIGER (n = 65) including cumulative dose reductions or treatment suspension were individualized and based on the severity of symptoms and an associated absolute eosinophil count (AEC, eosinophils/μL) of more than 900. Multivariate analysis for risk factors associated with OITIGER was performed in milk-OIT subjects.

RESULTS

Treatment modifications reduced the cumulative daily dosage load by a median of 50% (interquartile range, 50%-67%) in 43 of 65 (66.1%) patients, deferred dose increases in 2 of 65 (3.1%) patients, or temporarily suspended treatment in 18 of 65 (27.7%) patients. Two patients (3.1%) had no treatment intervention. Symptoms and eosinophilia abated on dosage modification, allowing for resumption of dose increases (n = 34) or reinitiation of treatment (n = 9) after a median of 29 (interquartile range, 20-56) and 19 (interquartile range, 17-44) days, respectively. OITIGER reoccurred during treatment in 10 of 54 (18.5%) patients, which resolved after further dose modification. In long-term follow-up (>3-26 months), 31 of 32 patients were asymptomatic with stable AECs. Patients with OITIGER had a higher OIT failure rate (P = .004) and were less likely to reach full desensitization (P < .001), as compared with asymptomatic patients (n = 684). Multivariate analysis identified several risk factors for OITIGER: starting dose more than 120 mg (P < .001; odds ratio, 7.14), second-month dose more than 4-fold over the starting dose (P = .037; odds ratio, 2.18), and baseline AEC more than 600/μL (P = .002; odds ratio, 3.2).

CONCLUSIONS

OITIGER is transient or reversible in most subjects, and its occurrence is related to OIT starting dose, its rate of increase, and baseline AECs.

Mechanisms of gastrointestinal allergic disorders

Gastrointestinal (GI) allergic disease is an umbrella term used to describe a variety of adverse, food antigen-driven, immune-mediated diseases. Although these diseases vary mechanistically, common elements include a breakdown of immunologic tolerance, a biased type 2 immune response, and an impaired mucosal barrier. These pathways are influenced by diverse factors such as diet, infections, exposure to antibiotics and chemicals, GI microbiome composition, and genetic and epigenetic elements. Early childhood has emerged as a critical period when these factors have a dramatic impact on shaping the immune system and therefore triggering or protecting against the onset of GI allergic diseases. In this Review, we will discuss the latest findings on the molecular and cellular mechanisms that govern GI allergic diseases and how these findings have set the stage for emerging preventative and treatment strategies.

Non-IgE-mediated gastrointestinal allergies-Do they have a place in a new model of the Allergic March

The rise in food allergy has been described as the "second wave" of the allergy epidemic, with some developed countries reporting a prevalence of 10% of challenge-proven food allergies. Recognition of the Allergic March has played a crucial role in identifying causality in allergic conditions, linking atopic dermatitis to food allergy and food allergy to other atopic disorders, thereby highlighting opportunities in prevention and the importance of early intervention. This publication will establish the value of weaving the less well-understood, non-IgE-mediated food allergy into the Allergic March and mapping its progression through childhood and its associated co-morbidities. The proposed non-IgE-mediated Allergic March highlights the concomitant presentation of gastrointestinal symptoms and atopic dermatitis as early presenting symptoms in confirmed non-IgE-mediated allergies and the later development of atopic co-morbidities, including asthma and allergic rhinitis, similar to the IgE-mediated Allergic March. This publication highlights recent observations of a link between non-IgE-mediated food allergy in early childhood and functional gastrointestinal disorders in later life and also the reported occurrence of extra-intestinal manifestations at later ages. Although significant limitations exist in regard to the proposed evolution of the Allergic March model, the authors hope that this publication will influence the management of non-IgE-mediated gastrointestinal allergies and inform future research and interventions.

Egg OIT in clinical practice (SEICAP II): Maintenance patterns and desensitization state after normalizing the diet

BACKGROUND

It is unknown which are the most suitable maintenance pattern and egg consumption to maintain the desensitization state after ending the oral immunotherapy (OIT). This multicenter, randomized, controlled trial compared two OIT maintenance patterns with pasteurized egg white (PEW), evaluating the egg consumption effect on the desensitization state after ending the OIT.

METHODS

One hundred and one children with confirmed egg allergy were randomized: 25 to an egg-free diet (CG) and 76 to an OIT year with PEW and two maintenance patterns, 38 patients to daily 3.3 g proteins (AG) and 38 to every two days (BG). PEW challenge (DBPCFC), adverse reactions, and immune markers were assessed at baseline, at the end of the OIT, and at 6 and 12 months later on ad libitum egg consumption (T0, T12, T18, and T24). A questionnaire evaluated the egg consumption at T18.

RESULTS

At T12, 64 of 76 (84.21%) OIT patients had reached total desensitization (32 AG and 32 BG) vs 4 of 25 (16.00%) CG who passed the PEW DBPCFC. Thirty (93.75%) AG vs 25 (78.12%) BG patients completed an OIT year. At T18, 27 of 29 (93.1%) AG vs 20 of 24 (83.3%) BG passed the PEW DBPCFC, 96% consuming at least two egg servings/week. At T24, 97.43% OIT patients passed the challenge. Most patients had adverse reactions, more frequent in the BG patients; frequency and severity of reactions decreased through the study. PEW skin prick test wheal and sIgE antibody serum levels similarly decreased in AG or BG, but AG patients had greater increase in PEW sIgG4 (P < 0.05).

CONCLUSIONS

Daily OIT maintenance achieves better adherence, effectiveness, and safety. Two egg servings/week ensure maintained desensitization after the end of an OIT year.

Baseline Gastrointestinal Eosinophilia Is Common in Oral Immunotherapy Subjects With IgE-Mediated Peanut Allergy

Rationale: Oral immunotherapy (OIT) is an emerging treatment for food allergy. While desensitization is achieved in most subjects, many experience gastrointestinal symptoms and few develop eosinophilic gastrointestinal disease. It is unclear whether these subjects have subclinical gastrointestinal eosinophilia (GE) at baseline. We aimed to evaluate the presence of GE in subjects with food allergy before peanut OIT.

Methods: We performed baseline esophagogastroduodenoscopies on 21 adults before undergoing peanut OIT. Subjects completed a detailed gastrointestinal symptom questionnaire. Endoscopic findings were assessed using the Eosinophilic Esophagitis (EoE) Endoscopic Reference Score (EREFS) and biopsies were obtained from the esophagus, gastric antrum, and duodenum. Esophageal biopsies were evaluated using the EoE Histologic Scoring System. Immunohistochemical staining for eosinophil peroxidase (EPX) was also performed. Hematoxylin and eosin and EPX stains of each biopsy were assessed for eosinophil density and EPX/mm² was quantified using automated image analysis.

Results: All subjects were asymptomatic. Pre-existing esophageal eosinophilia (>5 eosinophils per high-power field [eos/hpf]) was present in five participants (24%), three (14%) of whom had >15 eos/hpf associated with mild endoscopic findings (edema, linear furrowing, or rings; median EREFS = 0, IQR 0–0.25). Some subjects also demonstrated basal cell hyperplasia, dilated intercellular spaces, and lamina propria fibrosis. Increased eosinophils were noted in the gastric antrum (>12 eos/hpf) or duodenum (>26 eos/hpf) in 9 subjects (43%). EPX/mm² correlated strongly with eosinophil counts (r = 0.71, p < 0.0001).

Conclusions: Pre-existing GE is common in adults with IgE-mediated peanut allergy. Eosinophilic inflammation (EI) in these subjects may be accompanied by mild endoscopic and histologic findings. Longitudinal data collection during OIT is ongoing.

Pathophysiology of eosinophilic esophagitis: recent advances and their clinical implications

Introduction: Diagnostic and therapeutic strategies in eosinophilic esophagitis (EoE) are evolving. New knowledge regarding the pathophysiology of EoE has been the foundation for updated diagnostic recommendations and new therapeutic trials. Areas covered: We performed structured literature searches in Medline and PubMed, Cochrane meta-analyses, and abstracts of international congresses to review therapeutic approaches for EoE in July 2018. Additional articles were obtained by perusing the references of articles identified in the original PubMed search. Articles were excluded if they did not focus on the mechanism of disease, diagnosis, or treatment of humans with EoE. Expert commentary: Recent advances in the understanding of mechanisms underlying the pathology of EoE have resulted in significant change in the diagnostic algorithm for EoE, and are identifying promising potential targets for personalized medicine. There is a clinical need for improved targeted therapy for EoE, and better understanding the underlying pathophysiology of EoE will help to determine therapeutic targets. In this review, we highlight key mechanisms in the pathophysiology of EoE and how they are being utilized to change therapy in EoE.

Long-term Treatment With Proton Pump Inhibitors Is Effective in Children With Eosinophilic Esophagitis

OBJECTIVES

Proton pump inhibitor (PPI)-responsive eosinophilic esophagitis (EoE) is frequently observed in children, but data on long-term treatment are scarce. The objective of this study is to evaluate the long-term efficacy and safety of PPIs in children with EoE.

METHODS

This prospective study enrolled children with EoE and histological remission to an 8-week esomeprazole trial (1 mg/kg/dose, twice daily). Esomeprazole was maintained at 1 mg/kg/day for 1 year. Symptom recurrence and adverse events were monitored and a follow-up endoscopy was performed at 12 months. Complete histological remission was defined as ≤5 eosinophils/high-power field (eos/hpf), and partial histological remission as >5 and <15 eos/hpf. Patients had no concomitant dietary restrictions or topical steroid.

RESULTS

Fifty-seven children were included. Histological remission on maintenance PPI therapy was present in 40 children (70.1%; 95% CI 56.5-81.5). Long-term remission rate was higher in children with initial complete histological remission than in those with partial remission (81% vs 50%, P = 0.014). Forty-nine children (86%) remained asymptomatic. Pretreatment clinical and histological findings and median PPI dose/kg/day were similar between relapsers and nonrelapsers. Eleven out of 12 children (91.6%) receiving esomeprazole 0.5 mg · kg ·  day for 12 additional months remained in remission. Mild and transient side effects without requiring PPI avoidance were observed in 5 children.

CONCLUSIONS

Up to 70% of children with PPI-responsive EoE remain in histological and clinical remission on a low-dose maintenance treatment at 1-year follow-up, with adequate safety profile. Complete histological remission to an 8-week PPI trial was associated with higher probability of histological remission on maintenance therapy.

Skin inflammation exacerbates food allergy symptoms in epicutaneously sensitized mice

BACKGROUND

Cutaneous exposure to food antigen through impaired skin barrier has been shown to induce epicutaneous sensitization, thereby causing IgE-mediated food allergies.

OBJECTIVE

We examined whether skin barrier impairment following epicutaneous sensitization exacerbates food allergies.

METHODS

BALB/c mice were epicutaneously sensitized by repeated application of ovalbumin (OVA) to MC903-pretreated ear skin for 48 hours weekly and then intragastrically challenged with OVA. After the first oral challenge, the skin barrier was disrupted with topical application of MC903 or by tape-stripping. Mice were monitored for changes in body temperature and the occurrence of diarrhea after undergoing the second oral challenge. Serum levels of mouse mast cell protease-1 (mmcp1) and OVA-specific IgE, IgG1, IgG2a antibodies and OVA-specific IgA levels in intestinal lavage fluid were measured by ELISA. Tissue accumulation of eosinophils was determined histologically.

RESULTS

Epicutaneously sensitized mice developed anaphylaxis after intragastric challenge, as evidenced by diarrhea, decreased body temperature, and increased serum mmcp1 levels. Skin barrier disruption by MC903 treatment or tape-stripping exacerbated allergic reactions induced by oral challenge. MC903 treatment increased serum baseline and postchallenge mmcp1 levels. Topical pretreatment with dexamethasone alleviated allergic reactions that were exacerbated by MC903 treatment.

CONCLUSION

Even after eliminating exposure to the antigen, inflammation from skin barrier disruption can exacerbate the severity of food allergy symptoms. Serum baseline mmcp1 levels might be an effective marker for predicting the severity of antigen-induced allergic symptoms.

The Role of Proton Pump Inhibitors in the Management of Pediatric Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic, local, immune-mediated disorder characterized by symptoms of esophageal dysfunction and the presence of a dense eosinophilic infiltrate in the esophageal mucosa. Consensus diagnostic recommendations for EoE diagnosis included absence of histological response to a proton-pump inhibitor (PPI) trial, to exclude gastro-oesophageal reflux disease (GERD)-associated esophagitis. This recommendation exposed an entity known as "proton pump inhibitor-responsive esophageal eosinophilia" (PPI-REE), which refers to patients with EoE phenotype who are PPI-responsive and do not present GERD. In recent years, there is evidence which indicates that PPI-REE is a sub-phenotype of EoE with similar clinical, endoscopic, histological and genetic characteristics, as well as Th2-related inflammatory response. As a result, PPIs should be considered another treatment for EoE and not a diagnostic tool. PPI-REE was originally described in a case series which included two children and in two retrospective pediatric series. Later, a prospective pediatric study showed a high rate of response to PPIs at high doses with long-term maintenance at lower doses. PPI monotherapy in children with esophageal eosinophilia (EE) has been observed to reduce eotaxin-3 expression in epithelial cells and to practically reverse the allergy and inflammatory transcriptome. These data reveal that PPIs are also an effective treatment for EoE in pediatric patients, although more studies are necessary in order to define the best induction and maintenance treatment regimen, the long-term safety profile and their influence on the occurrence of fibrosis and esophageal remodeling.