Features of food-induced immediate response in the esophagus (FIRE) in a series of adult patients with eosinophilic esophagitis

Circulating Food Allergen-Specific Antibodies, Beyond IgG4, Are Elevated in Eosinophilic Esophagitis

INTRODUCTION

Eosinophilic esophagitis (EoE) is a chronic inflammatory condition with an incompletely understood immuno-pathogenesis involving a T2 response. EoE is triggered by food allergens although, unlike IgE-mediated allergies, it exhibits high IgG4 levels in oesophageal biopsies and in circulation. We investigated whether other antibody isotypes specific for food allergens are elevated in EoE and vary with disease activity.

METHODS

Plasma samples from patients with active EoE (n = 51), inactive EoE (n = 82) and non-EoE controls (n = 14) were analysed for food-specific IgG and IgA subclasses against casein, whey, wheat, egg and individual cow's milk allergens by ELISA. α-lactalbumin (Bos d 4)- and β-lactoglobulin (Bos d 5)-specific B cells were measured by flow cytometry in a subset of patients.

RESULTS

Food allergen-specific antibodies in the plasma varied across EoE subgroups and non-EoE controls. Elevated IgG4 in EoE patients confirmed a strong antibody response to food allergens, including casein, wheat and egg. αS1-casein (Bos d 9)-specific IgG, IgG2, IgG4, IgA1 and IgA2 differed between EoE and non-EoE controls and between active and inactive EoE. β-casein (Bos d 11, A1 variant) measurements showed higher levels of specific IgG2 and IgG4 in both EoE groups, whereas whey-derived allergens showed opposing responses: Bos d 4 responses favoured IgG4, and Bos d 5 responses were elevated across multiple IgG and IgA subclasses in EoE. Allergen-specific B cells could not be isolated from the circulation.

CONCLUSION

Our findings reveal distinct antibody profiles in EoE plasma, with elevated IgG and IgA subclasses beyond IgG4, highlighting a complex immune response to food allergens. Differential antibody responses support their clinical relevance in dietary management strategies, while the absence of allergen-specific B cells in circulation likely restricts antibody production to the inflamed oesophagus. Future research should explore whether these antibody profiles can guide personalised treatment and novel therapeutic targets in EoE.

[Eosinophilic esophagitis]

Eosinophilic esophagitis (EoE) was first described in the early 1990s. Initially a rarity, it is now the most common cause of dysphagia for solid foods in young adults. Its prevalence is estimated to be 1:2000. Mechanistically, EoE is characterized by a chronic type‑2 T‑helper cell (Th2) inflammation of the esophagus which is triggered by food allergens. It often occurs in association with other Th2-mediated diseases, such as asthma, atopic dermatitis, and chronic rhinosinusitis with nasal polyps. EoE is diagnosed based on an esophagogastroduodenoscopy with biopsies of the esophageal epithelium. The diagnosis can be established when both symptoms of esophageal dysfunction (usually dysphagia) and an eosinophilic infiltration of at least 15 eosinophils per high-power field (HPF) are present. EoE can be treated with drugs, diet, and endoscopic dilatation. In terms of diet, milk elimination appears most reasonable, particularly as first choice. Drug treatment includes proton pump inhibitors (PPI), topical steroids, and the biologic agent dupilumab. Endoscopic dilatation is effective but does not treat the underlying inflammation. Therefore, it should never be used alone, but rather as an add-on therapy. In cases where clinical suspicion of EoE is strong but no or only few eosinophils are detected in esophageal biopsies, the diagnosis of an EoE variant should be considered. This review article provides a detailed discussion of the epidemiology, clinical features, diagnosis, treatment, and variants of EoE.

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.

Clinical Evaluation of the Adult with Eosinophilic Esophagitis

Adult patients with eosinophilic esophagitis (EoE) typically present with a history of dysphagia for solids, sometimes with additional reflux-like pain and a history of prior food impactions. In contrast to these alarming symptoms, the general appearance and physical examination of adult patients with EoE is in line with apparently healthy individuals. Therefore, the diagnosis is based on a history of solid-food dysphagia and eosinophilic tissue infiltration. Importantly, the increasing prevalence of EoE variants, that is, typical EoE symptoms in the absence of a relevant eosinophilia, and several studies with eosinophil-targeting drugs, call the pathogenic role of eosinophils into question.

Eosinophilic esophagitis: does age matter?

INTRODUCTION

Eosinophilic esophagitis (EoE) is a chronic inflammatory disease of the esophagus with increasing prevalence worldwide. It is a multifactorial disease caused by a combination of immunologic, genetic, and environmental factors. The clinical presentation of EoE varies largely, especially between different age groups. While diagnostic criteria and therapeutic goals are similar in children and adults, there are differences in treatment, with a more cautious approach in children to avoid growth disturbances. In addition, close monitoring and follow-up are essential in children to ensure uninterrupted growth.

AREAS COVERED

A search in PubMed/MEDLINE, EMBASE, and SCOPUS databases was conducted to identify relevant studies published between January 2010 and January 2023 to give an overview of the state-of-the-art of EoE epidemiology, diagnosis, and treatment while focusing on similarities and differences between the adult and the pediatric population.

EXPERT OPINION

The current state of research indicates that while significant progress has been made in understanding and treating EoE, further research and advances are needed to optimize diagnostic strategies, tailored treatment approaches, monitoring, and follow-up, and improve long-term outcomes for patients. With further innovation, the management of EoE can become more precise and tailored, leading to better patient outcomes and improved quality of life.

Food-induced immediate response of the esophagus in pediatric eosinophilic esophagitis

BACKGROUND

Food-induced immediate response of the esophagus (FIRE) is a new phenomenon that has been described in eosinophilic esophagitis (EoE) patients. It is suspected when unpleasant symptoms occur suddenly on contact of the triggering food with the esophageal surface and recur with repeated exposures. It can often be mistaken for pollen-food allergy syndrome (PFAS) and solid food dysphagia. Data on FIRE is limited to one survey study and case reports, and there are no screening studies conducted on either adults or children with EoE. In this study, we aimed to screen children aged ≥7 years old with EoE for FIRE.

METHODS

Demographic data were collected from medical records. A questionnaire about FIRE was applied to all participants. Skin prick tests were done on suspected patients to identify the triggering foods. FIRE is defined as suitable clinical symptoms with suspected food allergen exposure.

RESULTS

A total of 78 patients (74.4% male, median age: 13.5 years) were included. Unpleasant and recurrent symptoms distinct from dysphagia with specific foods were reported in 16.7% of the patients, all of whom had concomitant allergic rhinitis (AR). The symptoms described by almost all patients were oropharyngeal itching and tingling (PFAS: 15.3%) excluding only one patient reporting retrosternal narrowing and pressure after specific food consumption (FIRE: 1.2%).

CONCLUSIONS

Although definitive conclusions regarding the true prevalence of FIRE cannot be made, it does not seem to be common as PFAS. However, it deserves questioning particularly in the presence of concurrent AR and/or PFAS in children with EoE.

A Practical Update on Pediatric Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is an emerging atopic disease of unknown etiology limited to the esophagus. The pathogenesis is still understood and is likely characterized by type 2 inflammation. Food allergens are the primary triggers of EoE that stimulate inflammatory cells through an impaired esophageal barrier. In children and adolescents, clinical presentation varies with age and mainly includes food refusal, recurrent vomiting, failure to thrive, abdominal/epigastric pain, dysphagia, and food impaction. Upper-gastrointestinal endoscopy is the gold standard for diagnosing and monitoring EoE. EoE therapy aims to achieve clinical, endoscopic, and histological ("deep") remission; prevent esophageal fibrosis; and improve quality of life. In pediatrics, the cornerstones of therapy are proton pump inhibitors, topical steroids (swallowed fluticasone and viscous budesonide), and food elimination diets. In recent years, much progress has been made in understanding EoE pathogenesis, characterizing the clinical and molecular heterogeneity, and identifying new therapeutic approaches. Notably, clinical, molecular, endoscopic, and histological features reflect and influence the evolution of inflammation over time and the response to currently available treatments. Therefore, different EoE phenotypes and endotypes have recently been recognized. Dupilumab recently was approved by FDA and EMA as the first biological therapy for adolescents (≥12 years) and adults with active EoE, but other biologics are still under consideration. Due to its chronic course, EoE management requires long-term therapy, a multidisciplinary approach, and regular follow-ups.

Characterization of eosinophilic esophagitis variants by clinical, histological, and molecular analyses: A cross-sectional multi-center study

OBJECTIVE

Physicians are increasingly confronted with patients presenting with symptoms of esophageal dysfunction resembling eosinophilic esophagitis (EoE), but absence of significant esophageal eosinophilia. The purpose of this study was to characterize and classify this group of EoE variants.

DESIGN

Patients from six EoE-centers with symptoms of esophageal dysfunction, but peak eosinophil counts of <60/mm² (<15/hpf) in esophageal biopsies and absence of gastro-esophageal reflux disease (GERD) were included. Clinical, endoscopic, (immuno)-histological, and molecular features were determined and compared with EoE, GERD, and healthy controls.

RESULTS

We included 69 patients with EoE variants. Endoscopic abnormalities were found in 53.6%. We identified three histological subtypes: EoE-like esophagitis (36/69, 52.2%), lymphocytic esophagitis (14/69, 20.3%), and non-specific esophagitis (19/69, 27.5%). Immunohistochemistry revealed-in contrast to EoE-no significant increase in inflammatory cell infiltrates compared with GERD and healthy controls, except for lymphocytes in lymphocytic esophagitis. EoE-typical Th2-response was absent in all EoE variants. However, considerable structural changes were detected based on histology and protein expression. Using next generation mRNA sequencing, we found the three EoE variants to have distinct molecular fingerprints partially sharing pronounced traits of EoE. Hierarchical sample clustering of RNA sequencing data confirmed the presence of an EoE-like (characterized by eotaxin-3 expression), non-specific, and lymphocytic variant cluster (characterized by CD3 cells and TSLP expression).

CONCLUSION

All EoE variants are clinically and histologically active conditions despite the absence of esophageal eosinophilia. EoE variants appear to be part of a disease spectrum, where classical EoE represents the most common and apparent phenotype.