Eosinophilic esophagitis in children: immunopathological analysis and response to fluticasone propionate

Medical treatment of eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic antigen-mediated eosinophilic inflammatory disease isolated to the esophagus. As a clinicopathologic disorder, a diagnosis of EoE requires a constellation of clinical symptoms of esophageal dysfunction and histologic findings (at least 15 eosinophils/high-powered microscope field (eos/hpf)). Current guidelines no longer require the failure of response to proton pump inhibitor medications to establish a diagnosis of EoE, but continue to suggest the exclusion of other etiologies of esophageal eosinophilia. The treatment goals for EoE are improvement in clinical symptoms, resolution of esophageal eosinophilia and other histologic abnormalities, endoscopic improvement, improved quality of life, improved esophageal function, minimized adverse effects of treatment, and prevention of disease progression and subsequent complications. Currently, there is no cure for EoE, making long-term treatment necessary. Standard treatment modalities include dietary modifications, esophageal dilation, and pharmacologic therapy. Effective pharmacologic therapies include corticosteroids, rapidly emerging biological therapies, and proton pump inhibitor medications.

OBJECTIVES

To evaluate the efficacy and safety of medical interventions for people with eosinophilic esophagitis.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, ClinicalTrials.gov, and WHO ICTRP to 3 March 2023.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing any medical intervention or food elimination diet for the treatment of eosinophilic esophagitis, either alone or in combination, to any other intervention (including placebo).

DATA COLLECTION AND ANALYSIS

Pairs of review authors independently selected studies and conducted data extraction and risk of bias assessment. We expressed outcomes as a risk ratio (RR) and as the mean or standardized mean difference (MD/SMD) with 95% confidence interval (CI). We assessed the certainty of the evidence using GRADE. Our primary outcomes were: clinical, histological, and endoscopic improvement, and withdrawals due to adverse events. Secondary outcomes were: serious and total adverse events, and quality of life.

MAIN RESULTS

We included 41 RCTs with 3253 participants. Eleven studies included pediatric patients while the rest recruited both children and adults. Four studies were in patients with inactive disease while the rest were in patients with active disease. We identified 19 intervention comparisons. In this abstract we present the results of the primary outcomes for the two main comparisons: corticosteroids versus placebo and biologics versus placebo, based on the prespecified outcomes defined of the primary studies. Fourteen studies compared corticosteroids to placebo for induction of remission and the risk of bias for these studies was mostly low. Corticosteroids may lead to slightly better clinical improvement (20% higher), measured dichotomously (risk ratio (RR) 1.74, 95% CI 1.08 to 2.80; 6 studies, 583 participants; number needed to treat for an additional beneficial outcome (NNTB) = 4; low certainty), and may lead to slightly better clinical improvement, measured continuously (standard mean difference (SMD) 0.51, 95% CI 0.17 to 0.85; 5 studies, 475 participants; low certainty). Corticosteroids lead to a large histological improvement (63% higher), measured dichotomously (RR 11.94, 95% CI 6.56 to 21.75; 12 studies, 978 participants; NNTB = 3; high certainty), and may lead to histological improvement, measured continuously (SMD 1.42, 95% CI 1.02 to 1.82; 5 studies, 449 participants; low certainty). Corticosteroids may lead to little to no endoscopic improvement, measured dichotomously (RR 2.60, 95% CI 0.82 to 8.19; 5 studies, 596 participants; low certainty), and may lead to endoscopic improvement, measured continuously (SMD 1.33, 95% CI 0.59 to 2.08; 5 studies, 596 participants; low certainty). Corticosteroids may lead to slightly fewer withdrawals due to adverse events (RR 0.64, 95% CI 0.43 to 0.96; 14 studies, 1032 participants; low certainty). Nine studies compared biologics to placebo for induction of remission. Biologics may result in little to no difference in clinical improvement, measured dichotomously (RR 1.14, 95% CI 0.85 to 1.52; 5 studies, 410 participants; low certainty), and may result in better clinical improvement, measured continuously (SMD 0.50, 95% CI 0.22 to 0.78; 7 studies, 387 participants; moderate certainty). Biologics result in better histological improvement (55% higher), measured dichotomously (RR 6.73, 95% CI 2.58 to 17.52; 8 studies, 925 participants; NNTB = 2; moderate certainty). We could not draw conclusions for this outcome when measured continuously (SMD 1.01, 95% CI 0.36 to 1.66; 6 studies, 370 participants; very low certainty). Biologics may result in little to no difference in endoscopic improvement, measured dichotomously (effect not estimable, low certainty). We cannot draw conclusions for this outcome when measured continuously (SMD 2.79, 95% CI 0.36 to 5.22; 1 study, 11 participants; very low certainty). There may be no difference in withdrawals due to adverse events (RR 1.55, 95% CI 0.88 to 2.74; 8 studies, 792 participants; low certainty).

AUTHORS' CONCLUSIONS

Corticosteroids (as compared to placebo) may lead to clinical symptom improvement when reported both as dichotomous and continuous outcomes, from the primary study definitions. Corticosteroids lead to a large increase in histological improvement (dichotomous outcome) and may increase histological improvement (continuous outcome) when compared to placebo. Corticosteroids may or may not increase endoscopic improvement (depending on whether the outcome is measured dichotomously or continuously). Withdrawals due to adverse events (dichotomous outcome) may occur less frequently when corticosteroids are compared to placebo. Biologics (as compared to placebo) may not lead to clinical symptom improvement when reported as a dichotomous outcome and may lead to an increase in clinical symptom improvement (as a continuous outcome), from the primary study definitions. Biologics lead to a large increase in histological improvement when reported as a dichotomous outcome, but this is uncertain when reported as a continuous outcome, as compared to placebo. Biologics may not increase endoscopic improvement (dichotomous outcome), but this is uncertain when measured as a continuous outcome. Withdrawals due to adverse events as a dichotomous outcome may occur as frequently when biologics are compared to placebo.

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.

Type 2 Inflammation in Eosinophilic Esophagitis: From Pathophysiology to Therapeutic Targets

Eosinophilic esophagitis (EoE) is a chronic immune-mediated disease of the esophagus characterized clinically by symptoms related to esophageal dysfunction and histologically by eosinophil-predominant inflammation, whose incidence is rising. It significantly affects patients’ quality of life and, if left untreated, results in fibrotic complications. Although broad consensus has been achieved on first-line therapy, a subset of patients remains non-responder to standard therapy. The pathogenesis of EoE is multifactorial and results from the complex, still mostly undefined, interaction between genetics and intrinsic factors, environment, and antigenic stimuli. A deep understanding of the pathophysiology of this disease is pivotal for the development of new therapies. This review provides a comprehensive description of the pathophysiology of EoE, starting from major pathogenic mechanisms (genetics, type 2 inflammation, epithelial barrier dysfunction, gastroesophageal reflux, allergens, infections and microbiota) and subsequently focusing on the single protagonists of type 2 inflammation (involved cells, cytokines, soluble effectors, surface proteins and transcription factors) that could represent present and future therapeutic targets, while summarizing previous therapeutic approaches in literature.

Gene therapy for a murine model of eosinophilic esophagitis

BACKGROUND

Eosinophils are specialized granulocytic effector cells that store and release highly active mediators used in immune defense. Eosinophils are also implicated in the pathogenesis of allergic disorders, including eosinophilic esophagitis (EoE), a chronic disorder characterized by infiltration of eosinophils into the esophagus and release of mediators that damage tissue, resulting in gastrointestinal morbidity, food impaction, and dysphagia. Treatment with elimination diets and/or topical corticosteroid therapy slow disease progression, but are complicated by adverse effects, limited compliance, and loss of response to therapy. We hypothesized that a single administration of an adeno-associated virus (AAV) coding for an anti-eosinophil monoclonal antibody that induces eosinophil clearance (anti-Siglec-F) would treat on a persistent basis a murine model of EoE.

METHODS

A mouse model of peanut-induced EoE that mimics the human disease was established by sensitization and challenge with peanut extract. After challenge, these mice exhibited an EoE phenotype demonstrated by elevated levels of blood eosinophils, infiltration of eosinophils in the esophagus with associated esophageal remodeling and food impaction.

RESULTS

The mice were treated with a single intravenous administration (10¹¹ genome copies) of AAVrh.10mAnti-Eos, a serotype rh.10 AAV vector coding for an anti-Siglec-F monoclonal antibody. Vector administration resulted in persistent, high levels of anti-Siglec-F antibody expression. Administration of AAVrh.10mAnti-Eos to the mouse model of EoE reduced blood (P < 0.02) and esophageal eosinophil numbers (P < 0.002) protected from esophageal tissue remodeling and minimized food impaction.

CONCLUSION

These results suggest that a single treatment with AAVrh.10mAnti-Eos has the potential to provide persistent therapeutic benefit to patients with EoE.

Medication Adherence Aligns with Age and a Behavioral Checklist but Not Symptoms or Quality of Life for Patients with Eosinophilic Esophagitis

OBJECTIVE

To measure adherence rates to swallowed topical steroids in children with eosinophilic esophagitis (EoE), describe factors related to adherence, and determine the association between adherence, symptoms, perceived disease severity, and quality of life in children with EoE.

STUDY DESIGN

Subjects in this cross-sectional study of 117 children between 5 and 18 years old with EoE completed the Pediatric Eosinophilic Esophagitis Symptoms Score V2.0 (PEESS), Pediatric Quality of Life Inventory Eosinophilic Esophagitis Module (PedsQL EoE), a Medication-Taking Checklist (MTC), and a demographics questionnaire. Adherence rate was calculated based on reported number of missed doses/prescribed doses in the last week. Parent-reported measures were used for children aged 5-12 years and self-report was used for children aged 13-18 years.

RESULTS

Adolescents had lower adherence rates than younger children (76.2 ± 24.5% vs 88.6 ± 16.7%, P = .002). Adherence rates were not associated with disease history, PEESS, or PedsQL EoE scores but instead correlated with MTC scores (Pearson r of 0.65, P < .001 for child-report and Pearson r of 0.74, P < .001 for parent-report). Symptomatology was associated with worse quality of life (PEESS Frequency: r = -0.7, P < .001; PEESS Severity: r = -0.71, P < .001 for children 5-12 years old; PEESS Frequency: r = -0.61, P < .001; PEESS Severity: r = -.5, P < .001 for adolescents).

CONCLUSIONS

Unrelated to their clinical history, demographic factors, symptoms, and quality of life, adolescents with EoE have lower medication adherence rates. The MTC may serve as a clinical tool to discuss adherence and provide targeted educational counseling regarding adherence interventions.

Impact of food challenge on local oesophageal immunophenotype in eosinophilic oesophagitis

BACKGROUND

Eosinophilic oesophagitis (EoE) is caused by the ingestion of food antigens. Dietary avoidance can result in clinical and histological remission, while food reintroduction can cause recurrence. It is uncertain if food antigen processing and immune activation occurs locally, in the oesophagus. Therefore, we performed a comparative study of the density of cell surface proteins (known to be involved with antigen presentation) on oesophageal tissue prior to, and following food antigen induced disease recurrence. A secondary aim was to consider novel biomarkers.

METHOD

Adult patients with a diagnosis of EoE, who had achieved histological remission with an elimination diet (<15 eosinophils per high power field at oesophageal biopsy), and who underwent food challenge with proven recurrence were included. Immunohistochemistry/immunofluorescence for CD1a, CD3, CD28, CD40, CD69, CD80, CD138, CXCR3 and HLA-DR was performed. Staining intensity of each biomarker (pixels/mm² ) was quantified by semi-automated analysis (Studio-FL software).

RESULTS

Fourteen cases of EoE (pre and post food challenge), 6 GORD and 5 healthy controls were included. HLA-DR, CD3, CD28, CD40 and CD 138 significantly increased with food reintroduction (P = <0.05). CD1a, CD 69, CD 80 and CXCR3 did not measurably change.

CONCLUSION

The presence of cell surface proteins typically associated with antigen presentation (following food antigen induced recurrence) suggests immune activation occurs in the oesophagus, and the relative lack of langerhans cells (CD1a) may indicate this cell type is unimportant. The cell surface protein CD 138 increases with disease recurrence, is not elevated in GORD or healthy controls, and has promise as a biomarker.

Red Between the Lines: Evolution of Eosinophilic Esophagitis as a Distinct Clinicopathologic Syndrome

Eosinophilic esophagitis (EoE) is characterized by eosinophilic infiltration of the esophageal mucosa and symptoms of esophageal dysfunction, including dysphagia. While EoE is still considered a rare disease, in practice it seems that more and more cases are diagnosed every week, research in the field is exploding, and the pipeline for treatments contains multiple agents, some of which are quite far along the development pathway. After only scattered cases and small series were published in the late 1970s and 1980, Stephen Attwood, Thomas Smyrk, Tom DeMeester, and James Jones, published in Digestive Diseases and Sciences in 1993 a seminal report that described a clinicopathologic syndrome of esophageal eosinophilia with dysphagia. This review details the origins of this paper and compares and contrast what was observed then and what is known now about multiple aspects of EoE, including the clinical presentation, diagnosis, epidemiology, natural history, and treatments and outcomes. Moreover, it will highlight how the paper presaged a number of controversies in the field that have yet to be resolved, as well as foreshadowed the collaborative, multidisciplinary approach that has led to rapid advances.

Pathogenesis of Eosinophilic Esophagitis: A Comprehensive Review of the Genetic and Molecular Aspects

Eosinophilic esophagitis (EoE) is a relatively new condition described as an allergic-mediated disease of the esophagus. Clinically, it is characterized by dysphagia, food impaction, and reflux-like symptoms. Multiple genome-wide association studies (GWAS) have been conducted to identify genetic loci associated with EoE. The integration of numerous studies investigating the genetic polymorphisms in EoE and the Mendelian diseases associated with EoE are discussed to provide insights into the genetic risk of EoE, notably focusing on CCL26 and CAPN14. We focus on the genetic loci investigated thus far, and their classification according to whether the function near the loci is known. The pathophysiology of EoE is described by separately presenting the known function of each cell and molecule, with the major contributors being eosinophils, Th2 cells, thymic stromal lymphopoietin (TSLP), transforming growth factor (TGF)-β1, and interleukin (IL)-13. This review aims to provide detailed descriptions of the genetics and the comprehensive pathophysiology of EoE.

Non-IgE Mediated Food Allergy

Food allergies, defined as an immune response to food proteins, affect as many as 8% of young children and 2% of adults in western countries, and their prevalence appears to be rising like all allergic diseases. In addition to well-recognized urticaria and anaphylaxis triggered by IgE antibody- mediated immune responses, there is an increasing recognition of cell-mediated disorders, such as eosinophilic esophagitis and food protein-induced enterocolitis. Non-IgE-Mediated gastrointestinal food allergies are a heterogeneous group of food allergies in which there is an immune reaction against food but the primary pathogenesis is not a production of IgE and activation of mast cells and basophils. Those diseases tend to affect mainly the gastrointestinal tract and can present as acute (FPIES) or chronic reaction, such as Eosinophilic Esophagitis (EoE), Food Protein-Induced Allergic Proctocolitis (FPIAP). The role of food allergy in Non-EoE gastrointestinal Eosinophilic disorders (Non- EoE EGID) is poorly understood. In some diseases like EoE, T cell seems to play a major role in initiating the immunological reaction against food, however, in FPIES and FPIAP, the mechanism of sensitization is not clear. Diagnosis requires food challenges and/or endoscopies in most of the patients, as there are no validated biomarkers that can be used for monitoring or diagnosis of Non-IgE mediated food allergies. The treatment of Non-IgE food allergy is dependent on diet (FPIES, and EoE) and/or use of drugs (i.e. steroids, PPI) in EoE and Non-EoE EGID. Non-IgE mediated food allergies are being being investigated.

Efficacy of Dairy Free Diet and 6-Food Elimination Diet as Initial Therapy for Pediatric Eosinophilic Esophagitis: A Retrospective Single-Center Study

PURPOSE

Management of eosinophilic esophagitis (EoE) varies from center to center. In this study, we evaluated the effectiveness of a dairy-free diet (DFD) and the 6-Food Elimination Diet (SFED) as initial therapies for the treatment of EoE in our practice.

METHODS

This was a retrospective study of children who had been treated for EoE at Connecticut Children's Medical Center, Hartford, CT, USA. Pre- and post-treatment endoscopy findings and histology results of patients treated with DFD or SFED were examined.

RESULTS

One hundred fifty-two patients (age 9.2±5.2 years, 76.3% male, 69.7% caucasian) met the inclusion criteria for initial treatment with DFD (n=102) or SFED (n=50). Response for DFD was 56.9% and for SFED was 52.0%. Response based on treatment duration (<10, 10-12, and >12 weeks) were 81.8%, 50.0%, and 55.1% for DFD, and 68.8%, 50.0%, and 40.0% for SFED. Response based on age (<6, 6-12, and >12 years) were 59.3%, 42.9%, and 67.5% for DFD, and 36.4%, 58.8%, and 72.7% for SFED. In patients treated with DFD, concomitant proton pump inhibitor (PPI) administration resulted in improved outcomes (p=0.0177). Bivariate regression analysis showed that PPI with diet is the only predictor of response (p=0.0491), however, there were no significant predictors on multiple regression analysis.

CONCLUSION

DFD and SFED are effective first line therapies for EoE. DFD should be tried first before extensive elimination diets. Concomitant therapy with PPI's may be helpful.

Estrogen and estrogen receptor signaling promotes allergic immune responses: Effects on immune cells, cytokines, and inflammatory factors involved in allergy

Hypersensitivity occurs when the body is stimulated by an antigen, resulting in an immune response, and leads to a physiological disorder or abnormal tissue trauma. Various immune cells, cytokines, and inflammatory mediators are involved in the immune responses related to allergic diseases, which are the core of anaphylaxis. Estrogen receptors are widely distributed in immune cells, which combine with estrogen and participate in allergic responses by affecting immune cells, cytokines, and inflammatory factors. We aimed to summarize the association between estrogen and allergic reactions to provide a scientific basis for understanding and studying the mechanisms of allergic diseases.

Efficacy of Budesonide vs Fluticasone for Initial Treatment of Eosinophilic Esophagitis in a Randomized Controlled Trial

BACKGROUND AND AIMS

Topical steroid treatments for eosinophilic esophagitis (EoE) include swallowed fluticasone from a multi-dose inhaler (MDI) or oral viscous budesonide (OVB) slurry, but the 2 have never been compared. We assessed whether OVB was more effective than MDI for initial treatment of patients with EoE.

METHODS

In a double-blind, double-dummy trial, patients with a new diagnosis of EoE were randomly assigned to groups given 8 weeks of either OVB (1 mg/4 mL) twice daily plus a placebo inhaler (n = 56) or fluticasone MDI (880 μg) twice daily plus a placebo slurry (n = 55). Primary outcomes were post-treatment maximum eosinophil counts per high-power field (eos/hpf) and a validated dysphagia score (dysphagia symptom questionnaire [DSQ]) at week 8. Secondary outcomes included endoscopic severity (validated EoE endoscopic reference score), histologic response (<15 eos/hpf), and safety.

RESULTS

In a modified intention-to-treat analysis, the subjects had baseline peak eosinophil counts of 73 and 77 eos/hpf in the OVB and MDI groups, respectively, and DSQ scores of 11 and 8. Post-treatment eosinophil counts were 15 and 21 in the OVB and MDI groups, respectively (P = .31), with 71% and 64% achieving histologic response (P = .38). DSQ scores were 5 and 4 in the OVB and MDI groups (P = .70). Similar trends were noted for post-treatment total EoE endoscopic reference scores (2 vs 3; P = .06). Esophageal candidiasis developed in 12% of patients receiving OVB and 16% receiving MDI; oral thrush was observed in 3% and 2%, respectively.

CONCLUSIONS

In a randomized clinical trial, initial treatment of EoE with either OVB or fluticasone MDI produced a significant decrease in esophageal eosinophil counts and improved dysphagia and endoscopic features. However, OVB was not superior to MDI, so either is an acceptable treatment for EoE. ClinicalTrials.gov ID NCT02019758.

Eosinophilic esophagitis-Where are we today?

OBJECTIVE

The objective of this review is to provide an overview of the practical diagnostic and therapeutic approaches to eosinophilic esophagitis and to increase the visibility of the disease among pediatricians.

SOURCES

A search of the MEDLINE, Embase, and CINAHL databases and recent consensus statements and guidelines were performed.

SUMMARY OF THE FINDINGS

The definition of eosinophilic esophagitis is based on symptoms and histology. It is important to rule out other diseases associated with esophageal eosinophil-predominant inflammation. It is not yet clear whether the increased prevalence is due to a real increase in incidence or a result of increased awareness of the disease. Various options for management have been used in pediatric patients, including proton pump inhibitors, dietary restriction therapies, swallowed topical steroids, and endoscopic dilations. More recently, proton pump inhibitor-responsive esophageal eosinophilia and eosinophilic esophagitis have been contemplated on the same spectrum, and proton pump inhibitors should be considered the initial step in the treatment of these patients.

CONCLUSIONS

Eosinophilic esophagitis is a relatively new disease with a remarkable progression of its incidence and prevalence in the past two to three decades, and diagnostic criteria that are constantly evolving. It is important to better understand the pathogenesis of the disease, the predisposing factors, the natural history, and the categorization of varying phenotypes to develop diagnostic and therapeutic strategies that meet the clinical needs of patients.

Safety and Efficacy of Budesonide Oral Suspension Maintenance Therapy in Patients With Eosinophilic Esophagitis

BACKGROUND & AIMS

We aimed to determine the safety and efficacy of budesonide oral suspension (BOS) maintenance therapy in patients with eosinophilic esophagitis (EoE).

METHODS

We performed an open-label extension study of a 12-week, multicenter, randomized, double-blind, placebo-controlled trial. Patients with EoE (11-40 years old) who completed double-blind BOS (n = 45) or placebo therapy (n = 37) received 24 weeks' open-label BOS (2.0 mg once daily for 12 weeks, with optional dose increase [1.5-2.0 mg twice daily] for 12 weeks thereafter). Predefined efficacy outcomes included: proportion of patients with a histologic response (≤6 eosinophils/high-power field [eos/hpf]) and change in mean peak eosinophil counts after 24 weeks. Analyses were stratified by patients who received placebo (placebo/BOS) or BOS (BOS/BOS) during the double-blind trial.

RESULTS

BOS was well tolerated and drug-related adverse events were uncommon (placebo/BOS, 19% [7/37]; BOS/BOS, 4% [2/45]). Incidence of oral candidiasis (1 per group) and esophageal candidiasis (placebo/BOS group, n = 4) remained low. Changes in morning serum cortisol levels were not clinically relevant. A histologic response was observed in 49% (16/33) of patients receiving placebo/BOS and 23% (9/39) receiving BOS/BOS. Mean peak eosinophil counts (baseline vs week 24 or early termination) were: placebo/BOS, 118.8 vs 29.1; P < .001 and BOS/BOS, 38.1 vs 72.4; P = .01. Of the patients who responded to double-blind therapy, 42% maintained a histologic response during the open-label extension; 4% of nonresponders gained response.

CONCLUSIONS

In an open-label extension study of patients with EoE, BOS was well tolerated and drug-related adverse events were uncommon. BOS maintained a histologic response in some initial responders, but few initial nonresponders had a response. ClinicalTrials.gov no: NCT01642212.

Molecular basis and cellular mechanisms of eosinophilic esophagitis for the clinical practice

Eosinophilic esophagitis (EoE) is a chronic, allergen-driven inflammatory esophageal disease characterized by predominantly eosinophilic inflammation leading to esophageal dysfunction. Recent efforts to understand EoE have increased our knowledge of the disease. Areas covered: Multiple cells, molecules, and genes interplay with early life environmental factors in the pathophysiology of EoE to converge in the esophageal epithelium at the center of disease pathogenesis. Epithelial cells constitute a mayor cytokine source for TSLP and Calpain-14; an impaired epithelial barrier function allowing penetration of food and microbiota-derived antigens is involved in triggering and maintaining inflammation. Eosinophil and mast cell-derived products, including TGFβ, together with IL-1β and TNFα, promote epithelial mesenchymal transition in EoE, contributing to tissue remodeling by synthetizing and depositing extracellular matrix in subepithelial layers. This article aims to provide a state-of-the-art update on the pathophysiology of EoE applied to clinical practice, and latest research and developments with potential interest to improve the diagnosis and treatment of patients with EoE are revised. Expert commentary: Preliminary approaches have provided promising results toward incorporating minimally invasive methods for patient diagnosis and monitoring in clinical practice. Early diagnosis and optimized therapies will allow for personalized medicine in EoE.

Pediatric eosinophilic esophagitis: updates for the primary care setting

PURPOSE OF REVIEW

Eosinophilic esophagitis (EoE) is a multifactorial, non-IgE-mediated inflammatory disorder of the esophagus and is the most common cause of food impaction in the pediatric population. The purpose of this review is to describe the current recommendations for diagnosis and management of EoE.

RECENT FINDINGS

New data has associated EoE with other allergic disorders of the atopic march as well as several risk factors, which predispose to allergic conditions. A subset of patients with esophageal eosinophilia respond to proton pump inhibitor (PPI) therapy with a partial or complete resolution of esophageal eosinophilia. Therefore, some patients can be treated with PPI alone. If this is unsuccessful, dietary elimination and swallowed steroid therapy are recommended for long-term management. There is a growing appreciation that untreated esophageal inflammation can lead to complications of fibrosis and stricture formation.

SUMMARY

The current review will focus on the diagnosis and management of EoE in the pediatric population. Identification and diagnosis of pediatric patients with EoE is critical to prevent long-term esophageal complications.

Pathophysiology of Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic inflammatory disease of the esophagus associated with an atopic predisposition which appears to be increasing in prevalence over the last few decades. Symptoms stem from fibrosis, swelling, and smooth muscle dysfunction. In the past two decades, the etiology of EoE has been and is continuing to be revealed. This review provides an overview of the effects of genetics, environment, and immune function including discussions that touch on microbiome, the role of diet, food allergy, and aeroallergy. The review further concentrates on the pathophysiology of the disease with particular focus on the important concepts of the molecular etiology of EoE including barrier dysfunction and allergic hypersensitivity.

Eosinophilic Esophagitis: an Important Comorbid Condition of Asthma?

Eosinophilic esophagitis and asthma are frequently found as comorbid conditions in children and adults along with other manifestations of atopic diathesis. These two conditions have similar T helper 2 responses-driven pathophysiology and share common management strategies such as using systemic corticosteroids and targeted anti-cytokine biologic therapies. Review of the literature finds that asthma is often a comorbid condition in eosinophilic esophagitis in both children and adults; however, the EoE-asthma relationship remains poorly characterized mechanistically and clinically. EoE and asthma commonly share several comorbid conditions such as allergic rhinitis and gastroesophageal reflux disease; therefore, addressing these comorbid conditions has the potential to improve and/or maintain control in both diseases. Similar to asthma, patients with EoE frequently demonstrate elevations in serum markers of atopy, including serum IgE levels, peripheral eosinophil counts, and T helper 2-related cytokines. Gastroesophageal reflux disease is thought to affect asthma through microaspirations, airway hyperresponsiveness, and increased vagal tone. The understanding of the relationship between gastroesophageal reflux and EoE is still evolving but seems to be bidirectional and interactive. In terms of treatment, similar classes of medications have been used in both EoE and asthma. In both children and adults, EoE remission can be achieved by food trigger avoidance and use of corticosteroids and biologic therapies. Asthma control is mostly achieved through inhaled corticosteroids, and long but biologic therapies are increasingly used in severe subsets of the disease. Significant clinical and mechanistic work needs to be accomplished to better understand the relationship between asthma, EoE, and their interaction with other allergic diseases. Understanding whether shared mechanisms exist can lead to the development of new diagnostic and therapeutic strategies. The following review examines the existing literature regarding prevalence, common comorbidities, and potential therapeutic approach and identifies gaps in knowledge and future directions.

Utility of 15(S)-HETE as a Serological Marker for Eosinophilic Esophagitis

The pathogenesis of eosinophilic esophagitis (EoE) involves Th2-mediated eosinophil recruitment and degranulation into the esophagus. However, measuring serum Th2 cytokines, eosinophils, and eosinophil-derived products does not reliably distinguish EoE from control populations. Non-invasive methods to diagnose EoE are lacking. We evaluated the diagnostic value of a novel candidate biomarker of EoE: 15(S)-hydroxyeicosatetraenoic acid (HETE). We used immunoassay to measure 15(S)-HETE and cytokine profiles in patients undergoing endoscopy with known or suspected EoE. 31 subjects were enrolled, 16 with EoE, and 15 with an alternate diagnosis. 15(S)-HETE was elevated in the EoE group compared to non-EoE group. The sensitivity and specificity of 15(S)-HETE to be used as a non-invasive marker is 50% and 80%, respectively. 15(S)-HETE may aid in the diagnosis of EoE.

Safety and Efficacy of Reslizumab for Children and Adolescents With Eosinophilic Esophagitis Treated for 9 Years

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic disease characterized by infiltration of eosinophils in the esophageal epithelium. There are limited treatment options for EoE. The rationale of the study was to evaluate the long-term safety and efficacy of reslizumab (RSZ) in pediatric patients who received RSZ in a randomized controlled trial (RCT) and expanded access program.

METHODS

Records of patients who received RSZ in our center were reviewed. Patients received RSZ 2 mg/kg (or placebo) every 4 weeks as part of the RCT, open-label extension (OLE), and compassionate use (CU). Data were analyzed as of their most recent evaluation in August 2017. Labwork, history, and examinations were conducted every 12 weeks. Biopsy results were compared from baseline (before RCT) and at the most recent evaluation. Adverse events (AE) were recorded.

RESULTS

Twelve patients entered the RCT at our center; 6 patients completed the OLE and 4 received RSZ through CU. Between the RCT, OLE, and CU periods, patients received 549 doses of RSZ (median 37, range 2-116). No serious AE were attributed to RSZ. Symptoms improved on treatment: dysphagia (42% vs 0%), abdominal pain (58% vs 0%), heartburn (18% vs 0%), vomiting (67% vs. 17%), reflux (58% vs. 0%). Median esophageal eosinophil count improved (35 eosinophils per high-power field vs 3, P < 0.001). Patients receiving RSZ maintain a relatively unrestricted diet.

CONCLUSIONS

RSZ appears to be safe in children with EoE over 9 years of treatment experience. Symptoms and eosinophil count improved considerably during treatment with RSZ despite a relatively unrestricted diet.

Biological therapies for eosinophilic gastrointestinal diseases

The scientific basis and the clinical application of mAb therapies that target specific immunologic pathways for eosinophilic gastrointestinal diseases are areas of active interest. There is a growing recognition of a subset of patients with eosinophilic esophagitis whose disease does not respond well to topical steroids or elimination diets. In addition, long-term use of corticosteroids presents possible risks that are currently being evaluated. Systemic therapy with a biologic agent offers potential advantages as a global approach that could limit the need for multiple, locally active medical therapies and allergen avoidance. The identification of novel biologic strategies is ongoing, and the recent validation of instruments and outcome measures to assess disease activity has proved essential in demonstrating efficacy. Studies using biologics that target IL-13 pathways in the treatment of eosinophilic esophagitis have demonstrated substantial promise.

Diagnosis and Treatment of Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a new disease. It is caused by a T-helper type 2 cell response to food antigens in contact with the esophageal mucosa. Although no single feature defines EoE, a constellation of compatible demographic, clinical, endoscopic, and histologic findings establish the diagnosis. Children present with symptoms and endoscopic patterns characteristic of inflammation, whereas adolescents and adults have manifestations of fibrosis and gross esophageal strictures. Clinical and endoscopic scoring systems have helped to standardize diagnosis. There is controversy in EoE research over the optimal endpoint for treatment. Although the most common endpoint is a reduced number of eosinophils in biopsies, changes in symptoms and endoscopic features are becoming important targets of therapy. We should improve our understanding of EoE progression and the need for maintenance therapy, and continue development of diagnostic tools that avoid endoscopy and biopsy analyses to more easily monitor disease activity.

Eosinophilic Esophagitis in Children and Adults

Adults and children with eosinophilic esophagitis (EoE) have distinct clinical and endoscopic presentations. Recognition of clinical signs, along with laboratory and endoscopic findings, is critical for the identification of patients with EoE because delay in diagnosis has been associated with esophageal remodeling and stricture formation. Clinical presentation varies considerably between adults and children. This is less due to differences in the disease and more due to patient differences. This article describes the similarities and differences in clinical presentation of children and adults with EoE, including areas of epidemiology, clinical and endoscopic presentation, pathophysiology, and treatment.

Intestinal overexpression of interleukin (IL)-15 promotes tissue eosinophilia and goblet cell hyperplasia

Interleukin (IL)-15 overexpression in eosinophilic gastrointestinal disorders is reported, but IL-15's role in promoting eosinophilic gastroenteritis is largely unknown. Therefore, we generated enterocyte-overexpressed IL-15 transgenic mice using Fabpi promoter. The Fabpi-IL-15 (iIL-15) transgenic mice showed induced IL-15 levels in the jejunum with a marked increase in jejunum eosinophils. However, no induction of eosinophilia in the blood or any other gastrointestinal segment was observed. Eosinophilia in the jejunum villus was substantially higher in iIL-15 mice compared to wild-type mice. In addition, goblet cell hyperplasia was also observed in the jejunum of iIL-15 mice. Furthermore, a significant correlation between induced IL-15 transcript and the IL-18 transcripts was observed. Therefore, to further understand the role of IL-18 in IL-15 mice associated gastrointestinal disorders, we generated iIL-15/IL-18Rα^-/- mice. Using these mice, we found that IL-18 has an important role in promoting IL-15-induced eosinophilia. As intestinal IL-15 overexpression is reported in food intolerance, we examined OVA intolerance in iIL-15 mice. The OVA-sensitized and challenged iIL-15 mice experienced weight loss, diarrhea and eosinophilia in the jejunum. Taken together, our findings demonstrate that intestinal IL-15 overexpression induces IL-18-dependent eosinophilia and immunoglobulins in the intestine that promotes food allergic responses.

Eosinophilic Esophagitis in Children

PURPOSE OF REVIEW

EoE is a significant cause of gastrointestinal morbidity affecting 1:2000. Patients with EoE typically have multiple atopic comorbidities, and additionally, many patients with EoE can be controlled well with elimination diets. The purpose of this review is to summarize the care of pediatric eosinophilic esophagitis patients.

RECENT FINDINGS

EoE represents a distinct clinical syndrome which is characterized by esophageal dysfunction and eosinophil-predominant inflammation of the esophageal mucosa. Patients with EoE can present with varying symptoms depending on their age; in this review, we review the presenting features of eosinophilic esophagitis in children as well as a diagnostic algorithm for EoE. The mucosal inflammation in EoE is driven by exposure to food antigens in many patients with EoE. Therefore, for the majority of patients, the mainstays of treatment remain food elimination diets or swallowed steroids. This review summarizes the diagnostic approach to eosinophilic esophagitis (EoE) in pediatric patients, focusing on the importance of accurate diagnosis and selection of appropriate therapy.

Diagnosis and Management of Eosinophilic Esophagitis

Unlike traditional food allergies, immunoglobulin E (IgE) is not a key mediator of eosinophilic esophagitis (EoE). Nonetheless, foods antigens are important triggers of EoE, and allergists play an important role in management of this chronic disease. This review addresses insights into the diagnosis and management as it relates to our evolving understanding about the pathogenesis of EoE.

Six-Food Elimination Diet and Topical Steroids are Effective for Eosinophilic Esophagitis: A Meta-Regression

BACKGROUND

Topical corticosteroids or six-food elimination diet is recommended as initial therapy for eosinophilic esophagitis (EoE).

AIMS

We aimed to summarize published manuscripts that report outcomes of these therapies for EoE.

METHODS

We performed a systematic review in MEDLINE, Web of Science, and Embase of published manuscripts describing topical fluticasone, topical budesonide, and six-food elimination diet as therapies for EoE. We conducted meta-analysis of symptom improvement and the change in peak mucosal eosinophil count, with heterogeneity between studies examined with meta-regression analysis.

RESULTS

Systematic review yielded 51 articles that met inclusion criteria. Summary histologic response rates were 68.3% [95% prediction limits (PL) 16.2-96.0%] for fluticasone, 76.8% (95% PL 36.1-95.1%) for budesonide, and 69.0% (95% PL 31.9-91.4%) for six-food elimination diet. Corresponding decreases in eosinophil counts were 37.8 (95% PL 19.0-56.7), 62.5 (95% PL 125.6 to -0.67, and 44.6 (95% PL 26.5-62.7), respectively. Symptom response rates were 82.3% (95% PL 68.1-91.1%), 87.9% (95% PL 42.7-98.6%), and 87.3% (95% PL 64.5-96.3%), respectively. Meta-regression analyses decreased the initially large estimate of residual heterogeneity and suggested differences in histologic response rate associated with study populations' baseline eosinophil count and age.

CONCLUSIONS

The literature describing topical corticosteroids and six-food elimination diet consists of small studies with diverse methods and population characteristics. Meta-analysis with meta-regression shows initial histologic and symptomatic response rates on the same order of magnitude for topical corticosteroids and six-food elimination diet, but heterogeneity of study designs prevents direct comparison of modalities.

Management of Eosinophilic Esophagitis Based on Pathophysiological Evidence

Over the past decades eosinophilic esophagitis (EoE) has been increasingly diagnosed, and significant progress has been made in our understanding of its pathophysiology. As EoE cannot be cured yet, treatment goals are suppression of disease activity and symptoms as well as the prevention of progression to a more severe disease phenotype. Disease-modifying treatment options can be divided into dietary therapy and immunosuppressive medications, of which topical steroids have been most investigated, yet are still prescribed off-label. In this review, we will summarize recent advances in our understanding of EoE and discuss the mechanisms of action of current treatment options, with emphasis on the role of the esophageal epithelial barrier and the effects of proton-pump inhibitors in the management of patients with EoE.

Cadherin 26 is an alpha integrin-binding epithelial receptor regulated during allergic inflammation

Cadherins (CDH) mediate diverse processes critical in inflammation, including cell adhesion, migration, and differentiation. Herein, we report that the uncharacterized cadherin 26 (CDH26) is highly expressed by epithelial cells in human allergic gastrointestinal tissue. In vitro, CDH26 promotes calcium-dependent cellular adhesion of cells lacking endogenous CDHs by a mechanism involving homotypic binding and interaction with catenin family members (alpha, beta, and p120), as assessed by biochemical assays. Additionally, CDH26 enhances cellular adhesion to recombinant integrin α4β7 in vitro; conversely, recombinant CDH26 binds αE and α4 integrins in biochemical and cellular functional assays, respectively. Interestingly, CDH26-Fc inhibits activation of human CD4⁺ T cells in vitro including secretion of IL-2. Taken together, we have identified a novel functional CDH regulated during allergic responses with unique immunomodulatory properties, as it binds α4 and αE integrins and regulates leukocyte adhesion and activation, and may thus represent a novel checkpoint for immune regulation and therapy via CDH26-Fc.

White Paper AGA: Drug Development for Eosinophilic Esophagitis

Since first characterized in 2 small case series in the early 1990s, eosinophilic esophagitis (EoE) has emerged as a commonly identified cause of esophageal symptoms in children and adults.1,2 Although several highly effectively dietary, pharmacologic, and endoscopic therapies have been reported, none is currently approved by either the US Food and Drug Administration (FDA) or European regulatory authorities. Evolving diagnostic criteria have challenged drug development, in particular the recognition of complex interactions with the most prevalent esophageal disorder, gastroesophageal reflux disease (GERD). Heterogeneity in the clinical presentations of affected children and adults has created difficulties with uniform inclusion criteria and the development of disease-specific, patient-reported outcome (PRO) instruments. Furthermore, controversies regarding the appropriate therapeutic endpoints of EoE have impeded the design of clinical trials. Despite these obstacles, collaborative efforts by investigators, industry, the FDA, and patient advocacy groups have resulted in substantial progress in drug development in EoE over the past 2 decades.3 The purpose of this article is to summarize discussions on EoE based on the 2016 Drug Development Conference sponsored by the Center for Diagnostics and Therapeutics of the American Gastroenterological Association.

Enhanced activation of eosinophils in peripheral blood and implications for eosinophilic esophagitis diagnosis

BACKGROUND AND AIM

Eosinophils are markers of the eosinophilic esophagitis (EoE) disease, and this work aimed to assess whether activation of eosinophils could be a noninvasive test to contribute for EoE diagnosis.

METHODS

The activation state of peripheral blood eosinophils in EoE patients and control subjects was assessed based on the morphological aspects of the eosinophil after adherence to slide. Cyclooxygenase-2 and 5-lipoxygenase expressions were evaluated by means of immunofluorescence microscopy to verify if and which eicosanoid pathway is triggered in eosinophils in blood in EoE.

RESULTS

The eosinophils of patients with EoE were significantly more activated than those of control individuals. The lowest percentage of normal eosinophils for control subjects was 40%, while the highest percentage of eosinophils of normal aspect for patients with EoE was 32%. Considering 36% as a cutoff for normal eosinophils, this value differentiated all individuals with EoE from individuals without the disease with a sensitivity of 100%, considering the diagnosis of EoE as currently defined. Eosinophils of EoE patients showed higher expression of cyclooxygenase-2 than those of control subjects.

CONCLUSIONS

The quantification of morphological changes in eosinophils is a feasible, easy, and reliable manner to identify EoE patients. Therefore, patients with symptoms of esophageal dysfunction showing higher than 36% activated eosinophils in peripheral blood could be a useful way to help definition and diagnostic criterion for EoE.

Budesonide Oral Suspension Improves Symptomatic, Endoscopic, and Histologic Parameters Compared With Placebo in Patients With Eosinophilic Esophagitis

BACKGROUND & AIMS

Pharmacologic treatment of eosinophilic esophagitis (EoE) is limited to off-label use of corticosteroids not optimized for esophageal delivery. We performed a randomized, controlled phase 2 trial to assess the ability of budesonide oral suspension (BOS), a novel muco-adherent topical steroid formulation, to reduce symptoms and esophageal eosinophilia in adolescents and adults with EoE.

METHODS

In this multicenter, randomized, double-blind, placebo-controlled, parallel-group trial, 93 EoE patients between the ages of 11 and 40 years with dysphagia and active esophageal eosinophilia were randomized to receive either BOS 2 mg or placebo twice daily for 12 weeks. Co-primary outcomes were change in Dysphagia Symptom Questionnaire (DSQ) score from baseline, and proportion of patients with a histologic response (≤6 eosinophils/high-power field) after treatment. Endoscopic severity scores and safety parameters were assessed.

RESULTS

At baseline, mean DSQ scores were 29.3 and 29.0, and mean peak eosinophil counts were 156 and 130 per hpf in the BOS and placebo groups, respectively. After treatment, DSQ scores were 15.0 and 21.5, and mean peak eosinophil counts were 39 and 113 per high-power field, respectively (P < .05 for all). For BOS vs placebo, change in DSQ score was -14.3 vs -7.5 (P = .0096), histologic response rates were 39% vs 3% (P < .0001), and change in endoscopic severity score was -3.8 vs 0.4 (P < .0001). Adverse events were similar between groups.

CONCLUSIONS

Treatment with BOS was well tolerated in adolescent and young adult patients with EoE and resulted in improvement in symptomatic, endoscopic, and histologic parameters using validated outcome instruments. ClinicalTrials.gov ID NCT01642212.

Eosinophils from eosinophilic oesophagitis patients have T cell suppressive capacity and express FOXP3

Eosinophilic esophagitis (EoE) is an antigen-driven T cell-mediated chronic inflammatory disease where food and environmental antigens are thought to have a role. Human eosinophils express the immunoregulatory protein galectin-10 and have T cell suppressive capacity similar to regulatory T cells (Tregs ). We hypothesized that one function of eosinophils in EoE might be to regulate the T cell-driven inflammation in the oesophagus. This was tested by evaluating the suppressive capacity of eosinophils isolated from the blood of adult EoE patients in a mixed lymphocyte reaction. In addition, eosinophilic expression of forkhead box protein 3 (FOXP3), the canonical transcription factor of Tregs , was determined by conventional and imaging flow cytometry, quantitative polymerase chain reaction (qPCR), confocal microscopy and immunoblotting. It was found that blood eosinophils from EoE patients had T cell suppressive capacity, and that a fraction of the eosinophils expressed FOXP3. A comparison of EoE eosinophils with healthy control eosinophils indicated that the patients' eosinophils had inferior suppressive capacity. Furthermore, a higher percentage of the EoE eosinophils expressed FOXP3 protein compared with the healthy eosinophils, and they also had higher FOXP3 protein and mRNA levels. FOXP3 was found in the cytosol and nucleus of the eosinophils from both the patients and healthy individuals, contrasting with the strict nuclear localization of FOXP3 in Tregs . To conclude, these findings suggest that the immunoregulatory function of eosinophils may be impaired in EoE.

Presence of intraepithelial food antigen in patients with active eosinophilic oesophagitis

BACKGROUND

Although eosinophilic oesophagitis (EoE) is putatively mediated by an abnormal response to food antigen, the oesophagus is considered relatively impermeable to large molecules.

AIM

To assess whether food antigens penetrate the oesophageal mucosa in patients with EoE.

METHODS

Anti-gliadin staining was performed in three groups: active EoE, inactive EoE and EoE patients on a low or gluten free diet. To appraise the specificity of our results, we also performed gliadin staining on six patients without oesophageal disease who were consuming gluten. The groups with EoE on gluten also underwent endoscopic infusion with gluten containing soy sauce and repeat biopsies during the endoscopy. We measured eosinophil density, dilated intercellular spaces (on a 0-4+ scale) and gliadin in oesophageal mucosa by immunofluorescence.

RESULTS

Patients with active EoE had significantly greater epithelial density of anti-gliadin staining when compared to inactive EoE (P < 0.0065) and gluten-free patients (P < 0.0008) at baseline and after soy infusion. Gliadin was not detected in non-EoE control patients. The distribution of gliadin was both cytoplasmic and nuclear. There was good correlation of dilated intercellular spaces grade and total gliadin staining intensity (r = 0.577, P = 0.0077). Acute oesophageal perfusion of a commercial gliadin-rich soy sauce did not lead to an increase in gliadin staining in active or inactive EoE.

CONCLUSION

These findings suggest, although do not prove, that antigen penetration in active eosinophilic oesophagitis might be facilitated by impairment of epithelial integrity.

Eosinophilic Esophagitis: A Comprehensive Review

Eosinophilic esophagitis (EoE) is an emerging chronic atopic clinical-pathologic disease with an estimated prevalence of 1/1000 similar to the one of Crohn's diseases. Usually, EoE is firstly suspected due to symptoms that are caused by esophageal dysfunction and/or fibrosis. EoE diagnosis is confirmed if the esophageal biopsy shows at least 15 eosinophils per high power field (eos/hpf) as a peak value in one or more of at least four specimens obtained randomly from the esophagus. Most of the patients affected by EoE have other atopic diseases such as allergic rhinitis, asthma, IgE-mediated food allergies, and/or atopic dermatitis. The local inflammation is a T helper type 2 (Th2) flogosis, which most likely is driven by a mixed IgE and non-IgE-mediated reaction to food and/or environmental allergens. Recently published genetic studies showed also that EoE is associated with single nucleotide polymorphism (SNP) on genes which are important in atopic inflammation such as thymic stromal lymphopoietin (TSLP) located close to the Th2 cytokine cluster (IL-4, IL-5, IL-13) on chromosome 5q22. When the EoE diagnosis is made, it is imperative to control the local eosinophilic inflammation not only to give symptomatic relief to the patient but also to prevent complications such as esophageal stricture and food impaction. EoE is treated like many other atopic diseases with a combination of topical steroids and/or food antigen avoidance.

Pharmacological treatment of eosinophilic gastrointestinal disorders

INTRODUCTION

Eosinophilic gastrointestinal disorders (EGIDs) are increasingly prevalent chronic inflammatory diseases characterized by eosinophilic infiltration of the gastrointestinal (GI) tract, in the absence of other known causes of eosinophilia.

AREAS COVERED

Clinical management of EGIDs is challenging, as there are currently limited therapeutic options available. The most common EGID is eosinophilic esophagitis (EoE), and rarer forms are eosinophilic gastritis, eosinophilic gastroenteritis, and eosinophilic colitis. Clinical presentation depends on the affected GI site. Recently duodenal eosinophilia has been recognized to commonly be present in patients with functional dyspepsia. This review will provide an overview of the pathogenesis and therapeutic management of EGIDs, with particular focus on the pharmacological strategies for these conditions. Expert commentary: Despite the considerable progress made in understanding the pathogenesis of EGIDs, there is still an urgent need for the development of specific and effective therapeutic approaches. Therapeutic management protocols are required that are based on rigorous clinical investigation in large prospective controlled trials to better understand the risks, benefits and limitations of each therapy. More well-defined and consistent end-points are also required to assess treatment outcomes, as there has been variability between patient reported outcomes, clinical outcomes, and histological outcomes in the studies to date.

Swallowed Fluticasone Propionate Is an Effective Long-Term Maintenance Therapy for Children With Eosinophilic Esophagitis

OBJECTIVES

Although effective in the treatment of eosinophilic esophagitis (EoE) in children, limited data exist on long-term safety and efficacy of swallowed topical corticosteroids. We investigated whether long-term use of swallowed fluticasone in children with EoE leads to sustained reduction in esophageal eosinophils, and endoscopic and clinical improvement.

METHODS

In an open-label, prospective, single-center study, we offered pediatric patients with active EoE fluticasone 2 puffs to swallow twice a day (strengths in μg/puff: 2-4 years: 44, 5-11 years: 110, ≥12 years: 220). Clinical, endoscopic, and histological assessments were performed at baseline and shortly after therapy. If histological remission was seen, fluticasone was continued with clinical follow-ups every 4 months and endoscopic and histological follow-ups yearly. Clinical scores were derived from eight symptoms (abdominal pain, nausea, vomiting, regurgitation, chest pain, dysphagia, food impaction, and early satiety). Endoscopic scores were derived from six features (rings, exudates, furrows, edema, stricture, and shearing). Scores were expressed as ratio (features present/total). In addition to peak eosinophils/high power field (HPF) (primary outcome), histological features (eosinophilic microabscesses, degranulation, superficial layering, basal zone hyperplasia, dilated intercellular spaces, and lamina propria fibrosis) were assessed. Median clinical and endoscopic scores and individual histologic features were compared over 4 time intervals: <4 months, 4-12 months, 13-24 months, and >24 months. Growth and adverse effects were monitored.

RESULTS

We enrolled 54 patients, 80% male, median age 6.5 years (range 2-17 years), 85% atopic (57% asthma, 68% allergic rhinitis, and 31% atopic dermatitis), and 74% with food allergy. Mean follow-up was 20.4 months, the longest being 68 months (5.7 years). Esophageal eosinophil counts significantly decreased (median peak eosinophils/HPF at baseline 72, <4 months: 0.5, 4-12 months: 1.75, 13-24 months: 10, and >24 months: 12, all P<0.01). All histological features significantly decreased from baseline to all follow-up time points (all P<0.01). Lamina propria fibrosis significantly decreased (% patients with fibrosis at baseline 92, <4 months: 41, 4-12 months: 50, 13-24 months: 45, and >24 months: 39, all P<0.01). Endoscopic features improved (score at baseline 0.37, <4 months: 0.17, 4-12 months: 0.17, 13-24 months: 0, and >24 months: 0.1, all P<0.01, except at >24 months: P<0.05). Symptoms improved (score at baseline 0.22, <4 months: 0, 4-12 months: 0.11, 13-24 months: 0.11, and >24 months: 0.11, all P<0.05 except at >24 months: P=0.05). In a mixed linear regression model that accounts for correlation of repeated observations in the patient in a per-patient analysis, we found that treatment with swallowed fluticasone led to a statistically significant and sustained decrease in peak esophageal eosinophil counts. Asymptomatic esophageal candidiasis was seen in three children but resolved with anti-fungal therapy. Height and weight z-scores followed expected growth curves.

CONCLUSIONS

We demonstrate that swallowed fluticasone is effective as a long-term maintenance therapy for children with EoE, without growth impediment or serious side effects.

Lymphocytic oesophagitis, eosinophilic oesophagitis and compound lymphocytic-eosinophilic oesophagitis I: histological and immunohistochemical findings

AIMS

To report four histological-immunohistochemical oesophagitis phenotypes.

METHODS

Oesophageal biopsies from 311 patients were stained with H&E and with CD3, a T cell marker. Additional immunohistochemical stains (n=413) were performed in 77 cases.

RESULTS

Four histological-immunohistochemical oesophagitis phenotypes were recorded: lymphocytic oesophagitis (LyE, ≥40 CD3+ lymphocytes/HPF in CD3 immunostain), eosinophilic oesophagitis (EoE, ≥15 eosinophils/HPF in H&E stain), lymphocytic infiltration (≤39 CD3+/HPF) and compound lymphocytic oesophagitis-eosinophilic oesophagitis (Co LyE-EoE). At index biopsy, 28.3% (n=88) had LyE, 21.2% (n=66) EoE, 10.6% (n=33) Co LyE-EoE and 39.9% (n=124) lymphocytic infiltration. A persistent oesophagitis phenotype was found in 42.5% (37/87) in the first follow-up biopsy, in 34.4% (21/61) in the second follow-up biopsy and in 48.1% (26/54) in the third follow-up biopsy. Using βF1 immunostain, two different surface T cell receptors were detected in LyE and Co Lye-EoE: one having ≥40 βF1+/HPF (βF1+ high) and the other having <39 βF1+/HPF (βF1+ low).

CONCLUSIONS

Based on the literature regarding the significance of intraepithelial lymphocytes (IELs) in the initiation of EoE, we submit that the IEL phenotypes in LyE might differ from those found in EoE as they were unable to elicit the same eosinophilic response. Recent studies disclosed that group 2 innate lymphocytes (ILC2s), enriched in EoE, remain undetected in CD3 immunostain as they lack surface markers for T, B, natural killer (NK) or NK T cells. If ILC2s also participate in the lymphocytic infiltration of EoE, then the frequency of cases with Co LyE-EoE here reported might have been much higher. The four oesophagitis phenotypes described are easy to recognise, provided that the dual staining procedure (H&E-CD3) is implemented.

Airway Manifestations of Pediatric Eosinophilic Esophagitis: A Clinical and Histopathologic Report of an Emerging Association

Objectives:

Pediatric eosinophilic esophagitis (EE) typically presents with dysphagia, vomiting, dyspepsia, or food impaction. The purpose of this study was to highlight the emerging association of pediatric EE and airway disease. An additional goal of this study was to describe the unique histopathologic findings found in EE and specifically explore the potential role of the cytotoxic protein called eosinophil major basic protein (MBP) in the pathophysiology of the disease.

Methods:

A retrospective review of 3 children with EE and airway symptoms included symptom presentation, aerodigestive tract endoscopic findings, ambulatory 24-hour dual pH-metry, allergy tests, treatment modalities, and treatment response. Esophageal tissue obtained from biopsies of each patient was evaluated by hematoxylin and eosin to determine the number of eosinophils per high-power field, by immunofluorescent anti-MBP staining to determine the presence of MBP, and by standard light and transmission electron microscopy to evaluate eosinophil migration patterns.

Results:

All patients had airway inflammation that included nonspecific laryngeal edema and grade I or II subglottic stenosis. Allergy testing was positive in the 2 patients who were tested. All patients had symptoms refractory to standard reflux therapy. Ambulatory pH-metry findings were normal in 2 patients and abnormal in 1 patient despite maximum treatment. Two patients had visual abnormalities seen during esophageal examination. The number of eosinophils ranged from 20 to 45 per high-power field. Intracellular and extracellular MBP deposition was found in all esophageal biopsy specimens. All patients were treated with swallowed fluticasone, and 2 had symptom relapses that required repeat treatment.

Conclusions:

The spectrum of pediatric EE can include upper airway disease. Intracellular and extracellular MBP deposition is present in EE, which potentially releases cytotoxic mediators that explain the esophageal and airway clinical symptoms seen in those with the disease. Eosinophilic esophagitis should be considered in patients with a history of atopic diseases and unexplained upper airway findings refractory to reflux treatment. Treatment with swallowed fluticasone is successful; however, relapses are common and require repeat treatment and close follow-up.

Clinical Characteristics of Eosinophilic Esophagitis in Children

Objectives:

The role of eosinophilic esophagitis (EE) in aerodigestive tract disorders in children is underestimated and overlooked, primarily because of a lack of understanding of this disorder by otolaryngologists. We sought to better characterize the clinical presentation of EE in order to increase awareness among otolaryngologists.

Methods:

We retrospectively reviewed 71 children with biopsy-proven EE to determine the most common symptoms and laboratory findings that should increase the clinical suspicion of EE.

Results:

Dysphagia, food impaction, and emesis were the most common symptoms in children with EE. Asthma was the most common airway diagnosis. Rhinosinusitis was the most common otolaryngological diagnosis. Food allergy was present in 60% of the children tested. Eighty-three percent of the children with elevated immunoglobulin E levels had thick linear streaking or patchy white exudate of the esophagus seen on esophagoscopy. Other major medical comorbidities existed in more than half of the children with EE, of which psychiatric disorders and other disorders of the aerodigestive tract were the most common.

Conclusions:

Eosinophilic esophagitis may contribute to treatment failure in patients with common and complicated aerodigestive tract disorders. To encourage clinicians to avoid overlooking the diagnosis, we present an evaluative algorithm to increase the suspicion of this entity.

Food allergy in children with refractory gastroesophageal reflux disease

BACKGROUND

Gastroesophageal reflux disease (GERD) and food allergy are frequent disorders of childhood. The purpose of this study was to determine the frequency of food allergy in children with refractory GERD.

METHODS

A total of 151 children resistant to pharmacologic GERD treatment underwent skin prick test, specific immunoglobulin E, eosinophil count, atopy patch test (APT), and oral food challenge, and were then divided into three groups according to the results of oral milk challenge and allergy work-up: group A1, positive oral milk challenge and positive IgE-mediated allergy test; group A2, positive milk challenge and negative IgE-mediated allergy test; and group B, negative oral milk challenge and negative allergy tests.

RESULTS

There were 35, 30 and 86 patients in group A1, group A2 and group B, respectively. A total of 28 of 35 patients in group A1 had cow's milk allergy and the other seven patients had egg allergy. APT positivity was more common in group A2. Endoscopic esophagitis was observed in six group A1 patients and in four group A2 patients. Bloody stools, atopic dermatitis and recurrent wheezing episodes were significantly more common in group A1 than in group A2 and group B (P < 0.001, for both).

CONCLUSION

Cow's milk allergy was observed frequently in children resistant to pharmacologic GERD treatment. Combined skin prick and specific IgE tests, APT and oral food challenge is essential for avoidance of unnecessary elimination diet.

Preferential Secretion of Thymic Stromal Lymphopoietin (TSLP) by Terminally Differentiated Esophageal Epithelial Cells: Relevance to Eosinophilic Esophagitis (EoE)

Eosinophilic esophagitis (EoE) is a chronic Th2 and food antigen-mediated disease characterized by esophageal eosinophilic infiltration. Thymic stromal lymphopoetin (TSLP), an epithelial derived cytokine which bridges innate and Th2-type adaptive immune responses in other allergic conditions, is overexpressed in esophageal biopsies of EoE subjects. However, the triggers of TSLP expression in the esophageal epithelium are unknown. The objective of the current study was to characterize TSLP expression in human esophageal epithelium in EoE in vivo and to determine the role of food antigens upon epithelial TSLP expression in vitro. Using immunohistochemistry (IHC), we localized TSLP in esophageal biopsies of active EoE (≥15 eos/hpf), inactive EoE (<15 eos/hpf) and non-EoE control subjects, and found that TSLP expression was restricted to the differentiated suprabasal layer of the epithelium in actively inflamed EoE biopsies. Consistent with these results in vivo, inducible TSLP protein secretion was higher in CaCl₂ differentiated telomerase-immortalized esophageal epithelial cells (EPC2-hTERT) compared to undifferentiated cells of the basal phenotype, following stimulation with the TLR3 ligand poly(I:C). To determine whether food antigens could directly induce epithelial TSLP secretion, differentiated and undifferentiated primary esophageal epithelial cells from EoE and non-EoE subjects were challenged with food antigens clinically relevant to EoE: Chicken egg ovalbumin (OVA), wheat, and milk proteins beta-lactoglobulin (blg) and beta-casein. Food antigens failed to induce TSLP secretion by undifferentiated cells; in contrast, only OVA induced TSLP secretion in differentiated epithelial cells from both EoE and control cell lines, an effect abolished by budesonide and NF-κb inhibition. Together, our study shows that specific food antigens can trigger innate immune mediated esophageal TSLP secretion, suggesting that esophageal epithelial cells at the barrier surface may play a significant role in the pathogenesis of EoE by regulating TSLP expression.