Eosinophilic esophagitis during sublingual and oral allergen immunotherapy

Real-world assessment of anaphylaxis and eosinophilic esophagitis with 12 SQ house dust mite SLIT-tablet sublingual immunotherapy

Background

Sublingual immunotherapy (SLIT) with 12 SQ house dust mile SLIT-tablet (HDM SLIT-tablet) for dust mite-induced perennial allergic rhinitis is reported as effective and safe. Although serious allergic reactions (SARs) and eosinophilic esophagitis (EoE) have infrequently occurred under trial conditions, the safety of HDM SLIT-tablet challenge under real-world conditions is unknown.

Objective

Our aim was to estimate the incidence of SARs and EoE due to HDM SLIT-tablet challenge.

Methods

Through use of administrative data from Kaiser Permanente Southern California, this prospective observational study identified patients newly administered HDM SLIT-tablet with follow-up until SLIT discontinuation or end of study. Suspected cases of SARs and EoE were detected by using International Classification of Diseases, 10th Revision, diagnosis and Current Procedural Terminology procedure codes and medication dispensing records. A 3-member clinical review committee of allergists adjudicated suspected reactions. The incidence rate of confirmed SARs and EoE per 1000 person years of exposure were determined.

Results

A total of 521 patients (93.9% adult and 6.1% pediatric) were exposed to HDM SLIT-tablet challenge from January 2018 through May 2023, for 440.4 person years of exposure. The patients' average age (SD) was 39.3 (14.1) years, 58.7% were female, 44.3% were non-Hispanic White, 40.3% had asthma, and 15.0% had gastroesophageal reflux disease. A SAR occurred in 1 adult patient, and during initial HDM SLIT-tablet challenge, SARs occurred in 2 pediatric adolescents, for an overall incidence of 6.8 SARs per 1000 patient years (95% CI = 2.2-21.1). EoE occurred in 1 adult patient, for an overall incidence of 2.3 cases of EoE per 1000 patient years (95% CI = 0.3-16.1).

Conclusions

This real-world study demonstrated that SARs and EoE were infrequent events with HDM SLIT-tablet use, supporting the safety of HDM SLIT-tablets and need for physician supervision with initial challenge.

Triggers for eosinophilic esophagitis (EoE): The intersection of food allergy and EoE

Eosinophilic esophagitis and IgE-mediated food allergy are both food-triggered diseases that are increasing in prevalence. They share many clinical links, including significant comorbidity and similar food triggers, and as atopic diseases, they likely share upstream mechanisms related to barrier function and signals leading to TH2 skewing. In this review, we focus on links between eosinophilic esophagitis and IgE-mediated food allergy with an emphasis on what insights may be derived from overlapping food triggers and immune phenotypes. Through further investigation of these connections, we may be able to better understand not only IgE-mediated food allergy and eosinophilic esophagitis but also general atopic response to food proteins and evolution of allergic response to food.

The Relationship Between Eosinophilic Esophagitis and Immunotherapy

Immunotherapy is a treatment approach based on the principle of incremental allergen exposure to achieve desensitization. Recently, oral immunotherapy has been introduced as a treatment of IgE-mediated food allergy. Some patients receiving oral immunotherapy for food allergy may develop eosinophilic esophagitis. Here, we summarize the literature examining this association, its treatment, and outcomes and discuss possible explanations for this clinical phenomenon. We further identify potential associations with aeroallergen sensitivity and other forms of immunotherapy including subcutaneous immunotherapy and sublingual immunotherapy. Finally, we discuss management of immunotherapy-induced eosinophilic esophagitis. Epicutaneous immunotherapy is highlighted as an area of therapeutic investigation.

Eosinophilic esophagitis improved by the discontinuation of sublingual immunotherapy for aeroallergens: a case report

Introduction

Eosinophilic esophagitis (EoE) is a chronic, immune-mediated inflammation of the esophagus, characterized by symptoms related to esophageal dysfunction, resulting from severe eosinophilic infiltration of the esophageal mucosa. It is common in atopic subjects and food antigens have been identified as the most common triggers. However, a seasonal variation in EoE prevalence, correlated with air pollen levels, is reported, suggesting that also aeroallergens may play a role. Little is known about the interplay between EoE and concomitant atopy treatment for aeroallergens.

Case presentation

We describe the case of an 11-year-old boy who presented dysphagia, vomiting, drooling, and chest pain while eating meat, developed 15 months after receiving sublingual immunotherapy (SLIT) for Alternaria (SUBLIVAC®). He underwent esophagogastroduodenoscopy (EGD) revealing severe eosinophilic predominant inflammation (100 eos/HPF), consistent with the diagnosis of EoE, not improving at the EGDs performed after both omeprazole and topical corticosteroids treatment, despite symptom improvement. Afterward, immunotherapy was switched from sublingual to injective form. At the EGD performed 1 month later, macroscopic examination of the esophageal mucosa was normal and eosinophilic infiltration was significantly decreased (5-10 eos/HPF).

Conclusions

SLIT may induce EoE by chronic antigenic exposure of oral mucosa in patients with a robust allergic susceptibility: while attenuating the IgE-mediated immune reactions, the progressive contact with the causative allergen might induce a chronic stimulation of the immune system with the consequent activation of tissue eosinophils. Our data suggest monitoring patients receiving SLIT for EoE symptoms and to discontinue SLIT on their earlier appearance, possibly as a first-line treatment.

Practical issues of oral immunotherapy for egg or milk allergy

Oral immunotherapy (OIT) has been recommended to reduce parental burden related to strict allergen avoidance and induce desensitization and immune tolerance for patients with long-lasting allergies to hen's eggs (HE) or cow's milk (CM). OIT should be monitored by pediatric allergists specializing in OIT and oral food challenge tests to manage allergic reactions. Although a previous history of anaphylaxis or multiple food allergies is not a contraindication to OIT, it is contraindicated if the patient has uncontrolled asthma, a malignancy, active systemic autoimmune disorders, or diseases requiring treatment with beta-blockers. A variety of OIT protocols have been de veloped to ensure better outcomes and safe up-dosing, including adjunctive therapies with biologics. This review provides insight into the practical issues of various immunotherapy options for children with HE or CM allergies.

Sublingual immunotherapy for cedar pollinosis possibly triggers eosinophilic esophagitis

Sublingual immunotherapy (SLIT) is an effective and popular treatment for cedar pollinosis. Although SLIT can cause allergic side effects, eosinophilic esophagitis (EoE) is a lesser-known side effect of SLIT. A 26-year-old male with cedar pollinosis, wheat-dependent exercise-induced anaphylaxis, and food allergies to bananas and avocados presented with persistent throat itching, difficulty swallowing, heartburn, and anterior chest pain 8 days after starting SLIT for cedar pollinosis. Laboratory examination showed remarkably elevated eosinophils, and esophagogastroduodenoscopy revealed linear furrows in the entire esophagus. Histological examination of an esophageal biopsy specimen revealed high eosinophil levels. The patient was strongly suspected with EoE triggered by SLIT. The patient was advised to switch from the swallow to the spit method for SLIT, and the symptoms associated with SLIT-triggered EoE were reduced after switching to the spit method. This case highlights the importance of recognizing SLIT-triggered EoE as a potential side effect of SLIT for cedar pollinosis, especially with the increasing use of SLIT in clinical practice. EoE can occur within a month after initiating SLIT in patients with multiple allergic conditions, as observed in our case. Furthermore, the spit method should be recommended for patients who experience SLIT-triggered EoE before discontinuing SLIT.

The KAAACI Guidelines for Sublingual Immunotherapy

Allergen immunotherapy is regarded as the only disease-modifying treatment option for various allergic conditions, including allergic rhinitis and asthma. Among the routes of administration of allergens, sublingual immunotherapy (SLIT) has gained clinical interest recently, and the prescription of SLIT is increasing among patients with allergies. After 30 years of SLIT use, numerous pieces of evidence supporting its efficacy, safety, and mechanism allows SLIT to be considered as an alternative option to subcutaneous immunotherapy. Based on the progressive development of SLIT, the current guideline from the Korean Academy of Asthma, Allergy, and Clinical Immunology aims to provide an expert opinion by allergy, pediatrics, and otorhinolaryngology specialists with an extensive literature review. This guideline addresses the use of SLIT, including 1) mechanisms of action, 2) appropriate patient selection for SLIT, 3) the currently available SLIT products in Korea, and 4) updated information on its efficacy and safety. This guideline will facilitate a better understanding of practical considerations for SLIT.

Safety of allergen immunotherapy in children

PURPOSE OF REVIEW

The current review discusses allergen immunotherapy (AIT) safety in children.

RECENT FINDINGS

AIT is a well tolerated and effective treatment for pediatric allergic conditions. While mostly well tolerated, severe reactions and near fatal reactions may occur with subcutaneous immunotherapy (SCIT) once in every 160 000 visits. Sublingual immunotherapy (SLIT) is associated more with local side effects, but severe systemic reactions, including anaphylaxis, have been rarely reported. Providing informed consent, recognizing risk factors for severe systemic reactions, such as severe or uncontrolled asthma, and mitigating the risk of severe reactions are important components to improving the safety of AIT.

SUMMARY

Overall, AIT is well tolerated in children, and data suggest that the incidence of systemic reactions in children receiving SCIT is no less than mixed populations of adult and pediatric patients. SLIT carries less risk for systemic reactions, and local oral site-application reactions are usually mild and resolve within 15 days of treatment.

A case of food and aeroallergen sublingual immunotherapy inducing eosinophilic esophagitis

Eosinophilic esophagitis (EoE) has been reported secondary to aeroallergen sublingual immunotherapy (SLIT) and food allergen oral immunotherapy. Gastrointestinal symptoms with food allergen SLIT are uncommon, with no prior reports of cases of food allergen SLIT inducing EoE. Here we report a patient who developed EoE secondary to food and aeroallergen SLIT therapy that resolved with SLIT cessation.

Food allergy: cause or consequence of pediatric eosinophilic esophagitis? Potential implications of ultraprocessed foods in prevention and management

Eosinophilic esophagitis (EoE) is a chronic, immune-mediated disease characterized by eosinophilic infiltration, leading to esophageal dysfunction, inflammation, and fibrotic remodeling. In the last few decades, there has been an increased prevalence of EoE at an alarming rate in the pediatric age. The pathogenesis of EoE is still largely undefined, and this limits the definition of effective strategies for the prevention and management of this condition. EoE is considered a multifactorial disease arising from a negative interaction between environmental factors and genetic background, causing an impaired esophageal epithelial barrier with subsequent abnormal allergen exposure activating type 2 (Th2) inflammation. Food antigens have been suggested as key players in Th2 inflammation in pediatric patients with EoE, but emerging evidence suggests a potential role of other dietary factors, including ultraprocessed foods, as possible triggers for the occurrence of EoE. In this paper, we discuss the potential role of these dietary factors in the development of the disease, and we propose a new approach for the management of pediatric patients with EoE.

International consensus statement on allergy and rhinology: Allergic rhinitis - 2023

BACKGROUND

In the 5 years that have passed since the publication of the 2018 International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis (ICAR-Allergic Rhinitis 2018), the literature has expanded substantially. The ICAR-Allergic Rhinitis 2023 update presents 144 individual topics on allergic rhinitis (AR), expanded by over 40 topics from the 2018 document. Originally presented topics from 2018 have also been reviewed and updated. The executive summary highlights key evidence-based findings and recommendation from the full document.

METHODS

ICAR-Allergic Rhinitis 2023 employed established evidence-based review with recommendation (EBRR) methodology to individually evaluate each topic. Stepwise iterative peer review and consensus was performed for each topic. The final document was then collated and includes the results of this work.

RESULTS

ICAR-Allergic Rhinitis 2023 includes 10 major content areas and 144 individual topics related to AR. For a substantial proportion of topics included, an aggregate grade of evidence is presented, which is determined by collating the levels of evidence for each available study identified in the literature. For topics in which a diagnostic or therapeutic intervention is considered, a recommendation summary is presented, which considers the aggregate grade of evidence, benefit, harm, and cost.

CONCLUSION

The ICAR-Allergic Rhinitis 2023 update provides a comprehensive evaluation of AR and the currently available evidence. It is this evidence that contributes to our current knowledge base and recommendations for patient evaluation and treatment.

Malaysian Society of Allergy and Immunology Consensus Statement on Sublingual Immunotherapy in Allergic Rhinitis

Allergic rhinitis (AR) is an IgE-mediated inflammatory disease of the upper airway. AR affects the patients' quality of life, is a known risk factor for asthma and a socio-economic burden. Allergen-specific immunotherapy (AIT), comprising sublingual immunotherapy (SLIT) and subcutaneous immunotherapy (SCIT), involves administering increasing doses of the causative allergen to induce clinical and immunologic tolerance to the allergens. It is the only currently available treatment for AR that has been proven to induce disease-modifying effects (i.e., long-term remission of allergic symptoms or potential prevention of asthma and new sensitizations). Although AIT is conventionally recommended for patients who are non-responsive to symptom-relieving pharmacotherapy, it is presently recommended as a first-line treatment for patients with moderate to severe AR who prefer a treatment with the potential for long-term remission. In light of the relatively recent implementation of AIT in Malaysia, guidelines on its appropriate indication and application are important to attain optimal outcomes. This consensus statement was developed by an expert group formed by the Malaysian Society of Allergy and Immunology to provide evidence-based recommendations for the practice of AIT in Malaysia. Patient and product selection, choice of AIT, and strategy towards an effective treatment outcome in AIT are presented.

Multimorbidities in Allergic Rhinitis-Current Evidence from Epidemiological Studies, Treatment Trials, and Molecular Data

PURPOSE OF REVIEW

Given that allergic rhinitis (AR) commonly coexists with other diseases, the present narrative review attempts a brief presentation of current theories on multimorbidities in relation to phenotypes, genotypes, age, and treatment responses with the term "multimorbidities" indicating the uncertainty regarding the primary defect, organ, or pathophysiologic mechanism involved.

RECENT FINDINGS

Though age-related manifestations allow for the generation of several hypotheses on AR's specific mechanisms, the various theories regarding the initiation or the aggravation of atopic disorders have yet to be proved. Multimorbid AR seems to have a different genetic basis from "stand-alone" AR as well a more severe phenotype. Most studies on the treatment of AR and its multimorbidities focus on allergen immunotherapy, which improves the atopic symptoms and may play a preventive role in the onset of new allergen sensitizations. The use of biological factors may also have a beneficial effect, even though it has currently been approved only for some comorbidities of AR, such as asthma. Employing the use of phenotypes and genotypes concerning multimorbidity broadens current knowledge, but further research is needed to develop diagnostic, stratificational, and predictive algorithms for single and multimorbid allergic diseases (Fig. 1). The real-time data obtained by mobile apps and the new insights on the pathophysiology of AR and its comorbidities will permit both timed preventive measures and better individualized and effective antiallergic treatment. Fig. 1 Current concepts and future trends in diagnosis and management of multimorbid allergic rhinitis.

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.

Oesophageal secretions reveal local food-specific antibody responses in eosinophilic oesophagitis

BACKGROUND

Eosinophilic oesophagitis (EoE) is associated with elevated IgG4 in oesophageal tissue and serum. Previously, we showed brush-collected oesophageal secretions of EoE patients contained food antigen-specific antibodies IgA and IgG4. It is unknown whether other food-specific antibodies are present along the surface of the oesophagus in EoE.

AIM

To identify whether immunoglobulins other than IgG4 and food-specific antibodies are elevated along the oesophageal mucosal surface in oesophageal secretions in EoE patients METHODS: Concentrations of total IgA, IgG1, IgG2, IgG3, IgG4, IgM and IgE were measured in oesophageal secretions from patients with active (n = 19) and inactive EoE (n = 9), and non-EoE controls (n = 10). Food-specific antibodies were measured using beads coupled to protein components from dairy, wheat and egg. Total immunoglobulin and cytokine and chemokine concentrations were measured in serum, saliva and oesophageal secretions of four patients with active EoE.

RESULTS

Oesophageal secretions have a unique immune profile. Patients with active EoE had elevated IgG2, IgG4 and IgM concentrations in oesophageal secretions compared to those with inactive EoE. Food-specific IgG1, IgG2, IgG4 and IgM were significantly increased in patients with active EoE compared to inactive EoE and non-EoE patients. Furthermore, active patients with a known dairy trigger display higher dairy-specific IgG1, IgG2, IgG4, IgM, IgA and IgE.

CONCLUSIONS

There is a distinct localised profile of immunoglobulins and food-specific antibodies found within oesophageal secretions in EoE. These findings expand our knowledge about the currently identified immune responses in EoE and suggest possible roles for multiple immunoglobulins and food-specific antibodies in the pathophysiology of EoE.

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.

Long-term outcomes of oral immunotherapy for anaphylactic egg allergy in children

Background

Studies of long-term oral immunotherapy (OIT) in children with anaphylactic egg allergy are limited.

Objective

Our aim was to investigate the long-term outcomes of OIT for anaphylactic egg allergy.

Methods

The participants included children (aged ≥ 5 years) with a history of anaphylaxis in response to eggs and objective reactions to oral food challenge (OFC) with 250 mg of egg protein. In the OIT group, the home starting dose of egg protein set during 5 days of hospitalization was ingested once daily and gradually increased to 1000 mg. Over the next year, participants temporarily discontinued OIT for 2 weeks and underwent OFC with 3100 mg of egg protein annually until they passed. The historical control group comprised patients who did not receive OIT and repeated OFCs annually.

Results

In the OIT group (n = 20), the baseline median egg white- and ovomucoid-specific IgE levels were 45.5 and 38.5 kUA/L, respectively. The rate of passing OFC with 3100 mg of egg protein gradually increased in the OIT group, with rates of 20% at 1 year, 35% at 2 years, and 55% at 3 years, which were significantly higher than the rates in the historical control group at 3 years (5% [P < .001]). In the OIT group, 5 anaphylaxis events (0.04%) occurred at home, and 1 participant required intramuscular adrenaline. Furthermore, egg white- and ovomucoid-specific IgE levels decreased significantly after 3 years in both groups, whereas in the OIT group, these specific IgG and IgG4 levels increased significantly after a year.

Conclusion

Long-term OIT accelerated immunologic changes and enabled ingestion of 3100 mg of egg protein in half of the participants with anaphylactic egg allergy.

Does allergen immunotherapy for allergic rhinitis prevent asthma?

Asthma and allergic rhinitis (AR) have overlapping clinical and pathologic features, sustained by an underlying T helper 2 bias, resulting in airway inflammation that extends from the nose to the lung. Children who are monosensitized often develop polysensitization over time, and they are at high risk of developing asthma. The effect of allergen immunotherapy (AIT) is allergen specific, resulting in symptom improvement and reduction in medication requirement. It is the only known treatment that alters the natural history of allergic disease and induces long-term remission. A bystander or allergen-nonspecific effect of AIT has also been proposed-that AIT to 1 allergen might reduce the risk of development of sensitization to other allergens. Furthermore, several observational studies and clinical trials, in seasonal (pollen) and perennial (house dust mite) AR, have investigated a protective effect of AIT to prevent asthma. The overall evidence favors an asthma preventive effect of AIT in AR to grass and birch tree pollen. Fewer studies have investigated the use of AIT in children with perennial AR due to house dust mite allergy to prevent asthma, and the results are less convincing. The use of AIT to reduce the risk of progression to asthma, in children with AR, potentially has high impact, and it will make AIT more attractive and cost-effective. However, most studies have been of small sample size or of poor design, using different allergens and AIT methodology, making it challenging to draw firm conclusions. There is a need to do adequately powered studies with optimal design and assess cost-effectiveness of this strategy.

Peripheral markers of allergen-specific immune activation predict clinical allergy in eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a T-cell-mediated disease that is caused by specific foods and results in esophageal dysfunction. Existing allergy testing modalities are not helpful when attempting to identify EoE-causal foods necessitating empiric food elimination and recurrent endoscopy. The goal of this study was to identify and compare allergen-specific immune features that can be assayed in a minimally invasive manner to predict clinical food allergy in EoE.

METHODS

We obtained blood samples from control subjects (n = 17), subjects with clinical EoE milk allergy (n = 17), and subjects with immunoglobulin E-mediated milk allergy (n = 9). We measured total and milk-specific plasma immunoglobulin G (IgG)4 levels and peripheral memory CD4⁺ T helper (T_H ) cell proliferation and cytokine production after stimulation with endotoxin-depleted milk proteins. Sensitivity and specificity for predicting clinical EoE milk allergy were calculated and compared between approaches.

RESULTS

Total and milk-specific IgG4 levels were not significantly different between control subjects and subjects with clinical EoE milk allergy. Stimulation with milk proteins caused T_H lymphocytes from subjects with clinical EoE milk allergy to proliferate more (%P1 of 38.3 ± 4.6 vs. 12.7 ± 2.8, p < 0.0001), and produce more type 2 cytokines (%IL-4⁺ of 33.7 ± 2.8 vs. 6.9 ± 1.6, p < 0.0001) than cells from control subjects. Milk-dependent memory T_H -cell proliferation (sensitivity and specificity of 88% and 82%, respectively) and interleukin 4 (IL-4) production (sensitivity and specificity of 100%) most strongly predicted clinical EoE milk allergy.

CONCLUSIONS

Peripheral markers of allergen-specific immune activation may be useful in identifying EoE-causal foods. Assaying milk-dependent IL-4 production by circulating memory T_H lymphocytes most accurately predicts clinical EoE milk allergy.

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.

A case series of sublingual immunotherapy-induced eosinophilic esophagitis: stop or spit

We experienced six cases with eosinophilic esophagitis (EoE). They complained of dysphagia, heartburn, or retrosternal discomfort. Endoscopy revealed typical findings of EoE and biopsy examination showed significant eosinophil infiltration in the esophageal epithelium. They received sublingual immunotherapy (SLIT) for allergic rhinitis. Discontinuation or spit method during SLIT resulted in improvement of symptoms, and endoscopic and histological remission. Previously six cases with SLIT-induced EoE has been reported. Our case series suggest that SLIT is clearly associated with the development of EoE by entering of aeroallergens from the luminal side of the esophagus and spit method during SLIT might be one of the therapeutic options for SLIT-induced EoE.

Atopy: A Collection of Comorbid Conditions

The concept of atopy was initially developed in the first quarter of the 20th century on the basis of clinical observations without any knowledge of pathogenic mechanisms. Atopy involves a collection of comorbidities that share pathogenic features, and atopic comorbidities affect outcomes of concomitant conditions rather than existing synchronously. The clinical importance of understanding the relationship of these conditions is necessary because the treatment of one condition influences the others, and the development of one leads to or precedes the development of another. Environmental influences and multigenetic predispositions result in complex relationships among the atopic conditions sharing a type 2 pathogenesis. The specialty of Allergy and Immunology is devoted to managing the comorbidities of atopy, and better understanding of their connections can improve patient care.

One march, many paths: Insights into allergic march trajectories

OBJECTIVE

The classical allergic march model posits that atopy begins in infancy with atopic dermatitis and progresses to asthma and allergic rhinitis in a subset of individuals. The growing prevalence and severity of allergic diseases have prompted renewed interest in refining this model. This review outlines epidemiologic evidence for the existence of allergic march trajectories (distinct paths of atopy development in individuals); reviews the roles that genetics, environment, and disease endotypes play in determining trajectory outcomes; and discusses the clinical utility of the trajectory model.

DATA SOURCES

PubMed search of English-language articles and reviews without date limits pertaining to the epidemiology, genetics, and immunologic mechanisms of allergic march trajectories and disease endotypes.

STUDY SELECTIONS

Studies and reviews were selected based on their high quality and direct relevance to the review topic.

RESULTS

Recent work in the field has revealed that immunoglobulin E-mediated food allergy and eosinophilic esophagitis are components of the allergic march. Furthermore, the field is acknowledging that variability exists in the number and sequence of allergic manifestations that individuals develop. These allergic march pathways, or trajectories, are influenced by genetic, environmental, and psychosocial factors that are incompletely understood.

CONCLUSION

Continued elucidation of the landscape and origins of allergic march trajectories will inform efforts to personalize allergic disease prevention, diagnosis, and treatment.

Clonally expanded, GPR15-expressing pathogenic effector TH2 cells are associated with eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is an allergic disorder characterized by the recruitment of eosinophils to the esophagus, resulting in chronic inflammation. We sought to understand the cellular populations present in tissue biopsies of patients with EoE and to determine how these populations are altered between active disease and remission. To this end, we analyzed cells obtained from esophageal biopsies, duodenal biopsies, and peripheral blood of patients with EoE diagnosed with active disease or remission with single-cell RNA and T cell receptor (TCR) sequencing. Pathogenic effector TH2 (peTH2) cells present in the esophageal biopsies of patients with active disease expressed distinct gene signatures associated with the synthesis of eicosanoids. The esophageal tissue-resident peTH2 population also exhibited clonal expansion, suggesting antigen-specific activation. Peripheral CRTH2+CD161- and CRTH2+CD161+ memory CD4+ T cells were enriched for either a conventional TH2 phenotype or a peTH2 phenotype, respectively. These cells also exhibited substantial clonal expansion and convergence of TCR sequences, suggesting that they are expanded in response to a defined set of antigens. The esophagus-homing receptor GPR15 was up-regulated by peripheral peTH2 clonotypes that were also detected in the esophagus. Finally, GPR15+ peTH2 cells were enriched among milk-reactive CD4+ T cells in patients with milk-triggered disease, suggesting that these cells are an expanded, food antigen-specific population with enhanced esophagus homing potential.

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.

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.

Protein and Antibody Engineering: Suppressing Degranulation of the Mast Cells and Type I Hypersensitivity Reaction

With an increase in atopic cases and owing to a significant role of mast cells in type I hypersensitivity, a therapeutic need to inhibit degranulation of mast cells has risen. Mast cells are notorious for IgE-mediated allergic response. Advancements have allowed researchers to improve clinical outcomes of already available therapies. Engineered peptides and antibodies can be easily manipulated to attain desired characteristics as per the biological environment. A number of these molecules are designed to target mast cells in order to regulate the release of histamine and other mediators, thereby controlling type I hypersensitivity response. The aim of this review paper is to highlight some of the significant molecules designed for the purpose.

Gastrointestinal Food Allergies and Intolerances

Adverse reactions to food include immune-mediated food allergies, celiac disease, and nonimmune-mediated food intolerances. Differentiating between these many disorders is important to guide us toward appropriate testing and management. Double-blind placebo-controlled food challenges are the gold standard for food allergy diagnosis but are difficult and time-consuming. In place of this, strong clinical history, other supportive tests, and oral food challenges are helpful. Some commonly available tests for food allergy and intolerances lack sufficient evidence for efficacy. Food intolerance diagnosis is largely based on history and supported by symptom improvement with appropriate dietary manipulation.

The Role of Food Allergy in Eosinophilic Esophagitis

Food allergy is often understood as an IgE-mediated hypersensitivity, characterized by allergic symptoms which occur “immediately” after the ingestion of a relevant food allergen. Increasingly, however, other food-related immune-mediated disorders are recognized in which symptoms can have a delayed onset and IgE does not play a central role. One of the described examples of the latter is eosinophilic esophagitis (EoE) – a disease defined pathologically by local eosinophilic inflammation in the esophagus in the setting of symptoms of esophageal dysfunction. The evidence that EoE is a food-mediated allergic disease includes i) almost all patients respond to an elemental diet and many respond to a diet in which dairy, wheat, eggs and/or soy are eliminated, ii) the presence of food-specific IgE and Th2 cells are consistent with a loss of tolerance to trigger foods and iii) many EoE patients have concomitant IgE-mediated food allergy and other allergic co-morbidities. This narrative review focuses on the hypothesis that EoE is a form of chronic food allergy. The goal is to describe similarities and differences in EoE and IgE-mediated food allergy, and to consider ways that these two increasingly common forms of food allergy are related to each other.

Interdisciplinary Significance of Food-Related Adverse Reactions in Adulthood

Background: Adults frequently interpret food-associated adverse reactions as indicators of a food allergy. However, the public perception of food allergy may differ from a clinician's point of view. The prevalence of patient-reported food allergy tends to be higher than physician-confirmed cases. Dermatological manifestations (urticaria, pruritus, dermatitis, and edema) are frequently reported by patients. Objective: The aim of this study was to describe patient-reported symptoms related to suspected food allergies and particularly to characterize and highlight the volume of patients who visit Budapest allergy clinics with suspected food allergies. Methods: In this prospective study, adult (≥18 years) patients were examined at the Allergology Outpatient Unit of the Dept. of Dermatology, Venereology, and Dermatooncology, Semmelweis University, Budapest. The examination included a detailed medical history; physical examination; and when necessary the measurement of allergen-specific serum immunoglobulin E (IgE) levels. Results: Data from 501 patients (393 women, 108 men) were analyzed. Intolerance to dietary biogenic amines occurred in 250 cases (250/501, 50%). Oral allergy syndrome was confirmed in 71 patients (71/501, 14%). Allergy to food preservatives was diagnosed in 14 (14/501, 3%) cases by a dermatologist-allergist specialist. Five individuals (5/501, 1%) were diagnosed with IgE-mediated food allergy. In some cases (28/501, 6%), edema-inducing/enhancing side effects of drugs were observed which patients had misattributed to various foods. Among the food groups considered to be provoking factors, the most frequently mentioned were fruits (198/501, 40%), milk/dairy products (174/501, 35%), and nuts/oilseeds (144/501, 29%). Overwhelmingly, urticaria (47%) was the most common dermatological diagnosis, followed by dermatitis (20%) and allergic contact dermatitis (8%). Conclusion: Improvement is needed in food allergy, food intolerance, and general nutritional knowledge among the general public. According to our data, perceived/self-reported food allergies were overestimated by adults when compared against physician-confirmed food allergies; however, other diseases potentially responsible for food-related problems were underestimated. The prevalence of oral allergy syndrome was high in the cohort. Intolerance to dietary biogenic amines was common, and although the role of dietary histamine and biogenic amine is not entirely understood in eliciting patients' symptoms, improvements in complaints were reported during the control visits.

How to approach adult patients with asymptomatic esophageal eosinophilia

As the awareness among gastroenterologists regarding endoscopic features suggesting eosinophilic esophagitis is increasing, individuals without symptoms of esophageal dysfunction are increasingly being found to have esophageal eosinophilia on biopsies performed during upper gastrointestinal endoscopies. However, the course of disease and the management of these asymptomatic individuals with esophageal eosinophilia remain elusive. In this review, we propose a definition of asymptomatic individuals with esophageal eosinophilia and discuss the prevalence, risk factors, and course of disease of this specific patient group. Furthermore, we have established a diagnostic and therapeutic pathway based on the most recent available data.

Oral and sublingual immunotherapy for food allergy

PURPOSE OF REVIEW

To critically appraise the recent most relevant studies in the rapidly advancing field of food oral and sublingual immunotherapy.

RECENT FINDINGS

Food allergen-specific immunotherapy via oral (OIT) and sublingual route (SLIT) increases the threshold of reactivity to peanut, cow's milk, egg, wheat, and many other foods in the majority of the treated individuals. This desensitized state is contingent upon the continued ingestion of the maintenance doses of the food. Permanent oral tolerance is achievable in a smaller subset of the treated individuals. The optimal duration of therapy has not been firmly established but is likely dependent on the phenotype (severity and persistence). Efficacy of food-OIT is superior compared with SLIT, whereas the safety of OIT is less favorable. Standardization of treatment protocols, maintenance dosing, duration of therapy, target populations and harmonization of the outcomes are top priorities at this stage.

SUMMARY

OIT and SLIT represent two different routes of food allergen-specific immunotherapy. Although significant progress has been made in the last decade, both treatment modalities are still in the very early stages of development and further investigations are necessary to optimize the protocols and improve safety while maximizing efficacy.

Outcomes for clinical trials of food allergy treatments

OBJECTIVE

Food allergy is a common condition that can have a significant impact on the quality of life of affected individuals and their caregivers. Recent years have witnessed an increased effort to identify new treatments for food allergy. Here, we review the need to identify core outcomes for measurement in clinical trials of food allergy treatments.

DATA SOURCES

We reviewed the literature regarding core outcome set development, the important role that these play in prioritizing patient-relevant outcomes, and the potential for core outcomes to accelerate the path to product marketing by allowing prompt and reliable evidence synthesis after trial publication.

STUDY SELECTIONS

We reviewed recent clinical trials of food allergy treatments to understand which outcomes have previously been measured, and also reviewed available core outcome set initiatives for other allergic conditions to understand which other outcomes might be explored in future trials.

RESULTS

Clinical trials of food allergy treatments have largely focused on outcomes that are relevant to investigators and commercial investors, especially the threshold of reactivity and immunologic changes. Future trials should consider addressing patient-important outcomes and should report the experiences of both adult and child participants and their caregivers.

CONCLUSION

There is a pressing need for core outcome set development for food allergy treatment trials.

Early Life Risk Factors in Pediatric EoE: Could We Prevent This Modern Disease?

Eosinophilic esophagitis (EoE) is a chronic antigen-mediated inflammatory disease that affects the esophagus. In the last 20 years, a large number of epidemiological studies showed a significant increase in the incidence and prevalence of EoE, especially in developed countries. This phenomenon might correlate to the overall increase in pediatric allergic diseases or might be a result of improved medical awareness and knowledge through modern diagnostic instruments. Since 1993, when EoE was first recognized as a distinct clinical entity, several signs of progress in the pathophysiology of EoE were achieved. However, a few studies reported data on early risk factors for pediatric EoE and how these factors may interfere with genes. Currently, the most defined risk factors for EoE are male sex, Caucasian race, and atopic comorbidities. Other putative risk factors may include alterations in epithelial barrier function and fibrous remodeling, esophageal dysbiosis, variation in the nature and timing of oral antigen exposure, and early prescription of proton pump inhibitors and antibiotics. Notably, the timing and nature of food antigen exposure may be fundamental in inducing or reversing immune tolerance, but no studies are reported. This review summarized the current evidence on the risk factors that might contribute to the increasing development of EoE, focusing on the possible preventive role of early interventions.

Could This Be IT? Epicutaneous, Sublingual, and Subcutaneous Immunotherapy for the Treatment of Food Allergies

PURPOSE OF REVIEW

Over the last decade, there has been a spark in innovation in the development of therapies for food allergy. Herein, we describe the background and recent advances for food-specific immunotherapies including epicutaneous (EPIT), sublingual (SLIT), and subcutaneous (SCIT).

RECENT FINDINGS

Studies have progressed most quickly for the treatment of peanut allergy. Data from the phase 3 EPIT trial add to the accumulating evidence that this will be a viable therapy for peanut allergy. Studies for SLIT and SCIT remain in earlier phases with promising results. This is an exciting era for the treatment of food allergy. Multiple therapies are under investigation, each with their own potential advantages. Specific strengths and limitations of each of these therapies may provide an opportunity to personalize the choice of therapy for individual patients.

Current Trends in Tolerance Induction in Cow's Milk Allergy: From Passive to Proactive Strategies

This review addresses the current strategies of inducing tolerance development in infant and childhood cow's milk protein allergy (CMPA). The change in prevention strategies for CMPA has been emphasized based on the lack of evidence to support the efficacy of food allergen avoidance in infancy and the concept of the dual-allergen-exposure hypothesis, which suggests that allergen exposure through the skin leads to sensitization, whereas early oral consumption of allergenic food protein induces oral tolerance. The new approach is based on the likelihood of early introduction of allergenic foods to the infant's diet to reduce the development of food allergies through oral tolerance induction. The latest treatment guidelines recommend the continuation of breast feeding and the elimination of cow's milk and products from the maternal diet in exclusively breast-fed infants with CMPA, the use of an extensively hydrolyzed infant formula (eHF) with proven efficacy in CMPA as the first elimination diet in formula-fed infants with CMPA and the use of amino acid-based formula (AAF) in severe cases, such as anaphylaxis, enteropathy, eosinophilic esophagitis, and food protein-induced enterocolitis syndrome (FPIES), as well as cases of multiple system involvement, multiple food allergies, and intolerance to extensively hydrolyzed formula (eHF). In conclusion, this paper presents the current knowledge on tolerance development in infants and children with CMPA to increase the awareness of the clinicians concerning the new approaches in CMPA treatment Tolerance development is considered a relatively new concept in CMPA, inducing a shift in interventions in CMPA from a passive (avoidance of responsible allergen) toward a proactive (tolerance induction) strategy.