Role of Environmental Factors in the Development of Pediatric Eosinophilic Esophagitis

Epidemiologic and Clinical Clues to the Etiology of Eosinophilic Esophagitis

Despite the rising prevalence and incidence of eosinophilic esophagitis (EoE), the etiology and pathophysiology remain unknown. Studies to date suggest that complex interactions between genetic and environmental risk factors result in the development and presentation of disease. Examining environmental factors both in the early life and later life exposures offers potential clues for the development of EoE, although challenges exist in making causal inferences due to diagnostic delay and access, ascertainment biases, and misclassification of cases. The authors review studies supporting early life factors as etiologic factors in the development of EoE.

Maternal and Infant Antibiotic and Acid Suppressant Use and Risk of Eosinophilic Esophagitis

Importance

Eosinophilic esophagitis (EoE), a chronic disease with significant patient and health care burden, has increased rapidly in incidence across many countries. Elucidating risk factors for disease development is a priority for health care practitioners and patients.

Objective

To evaluate the association of maternal and infant use of antibiotics and acid suppressants with the development of EoE.

Design, Setting, and Participants

This was a population-based, case-control study of pediatric EoE (1996-2019) in Denmark using pathology, prescription, birth, inpatient, and outpatient health registry data and with complete ascertainment of all EoE cases among Danish residents born between 1997 and 2018. Study data were analyzed from September 2020 to August 2023.

Exposures

Maternal and infant use of antibiotics and acid suppressants, examining medication class, timing, and frequency of use.

Main Outcome and Measure

Development of EoE.

Results

Included in the study was a total of 392 cases and 3637 sex- and year of birth-matched controls with a median (IQR) age of 11.0 (6.0-15.0) years, 2772 male individuals (68.8%), and 1257 female individuals (31.2%). Compared with children with no antibiotic prescriptions filled during infancy, those with any use of an antibiotic had an associated 40% increase in risk of EoE (adjusted odds ratio [aOR], 1.4; 95% CI, 1.1-1.7). Those with 3 or more prescriptions had an associated 80% increase in risk of EoE (aOR, 1.8; 95% CI, 1.3-2.5). Frequency of maternal antibiotic use was associated with an increased risk (1 prescription: aOR, 1.4; 95% CI, 1.0-1.8; 3≤ prescriptions: aOR, 2.1; 95% CI, 1.4-3.2). Risk was highest for use in the third trimester and in the first 6 months from birth. Any acid suppressant use in infancy was associated with increased risk of EoE (aOR, 15.9; 95% CI, 9.1-27.7). Restriction of cases to those diagnosed at 5 years or older yielded similar results (aOR, 11.6; 95% CI, 5.5-24.8). For maternal use, 3 or more prescriptions were associated with an increased risk of EoE for her offspring (aOR, 5.1; 95% CI, 1.8-14.8).

Conclusions and Relevance

Maternal and infant antibiotic use were associated with increased risk of developing EoE, in a dose-response manner, and the magnitude of association was highest for exposure near the time of delivery. Increased risk was also observed with maternal and infant acid suppressant use. Exposure during early life, a period of known developmental susceptibility, may confer the greatest risk and opportunity for risk mitigation.

Expression profiling identifies key genes and biological functions associated with eosinophilic esophagitis in human patients

Introduction

Eosinophilic Esophagitis (EoE) is a chronic allergic disease characterized by progressive inflammation of the esophageal mucosa. This chronic inflammatory disorder affects up to 50 per 100,000 individuals in the United States and Europe yet is limited in treatment options. While the transcriptome of EoE has been reported, few studies have examined the genetics among a cohort including both adult and pediatric EoE populations. To identify potentially overlooked biomarkers in EoE esophageal biopsies that may be promising targets for diagnostic and therapeutic development.

Methods

We used microarray analysis to interrogate gene expression using esophageal biopsies from EoE and Control subjects with a wide age distribution. Analysis of differential gene expression (DEGs) and prediction of impaired pathways was compared using conventional transcriptome analysis (TAC) and artificial intelligence-based (ADVAITA) programs. Principal Components Analysis revealed samples cluster by disease status (EoE and Control) irrespective of clinical features like sex, age, and disease severity.

Results

Global transcriptomic analysis revealed differential expression of several genes previously reported in EoE (CCL26, CPA3, POSTN, CTSC, ANO1, CRISP3, SPINK7). In addition, we identified differential expression of several genes from the MUC and SPRR families, which have been limited in previous reports.

Discussion

Our findings suggest that there is epithelial dysregulation demonstrated by DEGs that may contribute to impaired barrier integrity and loss of epidermal cell differentiation in EoE patients. These findings present two new gene families, SPRR and MUC, that are differentially expressed in both adult and pediatric EoE patients, which presents an opportunity for a future therapeutic target that would be useful in a large demographic of patients.

Early life exposures as risk factors for non-esophageal eosinophilic gastrointestinal diseases

OBJECTIVES

Early life exposures increase risk of eosinophilic esophagitis (EoE), but it is unknown whether they contribute to increased risk for non-EoE eosinophilic gastrointestinal diseases (EGIDs). We aimed to assess the association between prenatal, antenatal, and early life factors and non-EoE EGIDs.

METHODS

We conducted a case-control study based in EGID Partners, an online patient-centered research network. Adults (≥18 years) with non-EoE EGIDs, caregivers of children <18 years of age with an EGID, and non-EGID adult controls were eligible. Subjects completed our Early Life Exposure Questionnaire, detailing maternal and early childhood exposures. We assessed for associations between non-EoE EGIDs and early life exposures, focusing on exposures previously evaluated in association with EoE.

RESULTS

We analyzed 61 non-EoE EGID cases and 20 controls. Of the EGID cases, 14 had eosinophilic gastritis, 19 had eosinophilic enteritis, 6 had eosinophilic colitis, and 22 had multiple areas affected; additionally, 30 had esophageal involvement. Relative to controls, EGID cases were more likely to have had antenatal/perinatal pregnancy-related complications (43% vs 13%; p = 0.02), NICU admission (20% vs 0%; p = 0.03), and antibiotics in infancy (43% vs 10%; p = 0.01). With adjustment for age at diagnosis, we observed increased odds of an EGID for pregnancy complications (aOR 3.83; 95% CI: 0.99-14.9) and antibiotic use in infancy (aOR 7.65; 95% CI: 1.28-45.7).

CONCLUSIONS

Early life factors, including pregnancy complications, NICU admission, and antibiotics in infancy, were associated with development of non-EoE EGIDs. The impact of early life exposures on non-EoE EGID pathogenic mechanisms should be investigated.

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.

Allergen-free extracts from birch, ragweed, and hazel pollen activate human and guinea-pig submucous and spinal sensory neurons

BACKGROUND

Non-allergenic, low molecular weight components of pollen grains are suspected to trigger changes in gut functions, sometimes leading to inflammatory conditions. Based on extensive neuroimmune communication in the gut wall, we investigated the effects of aqueous pollen extracts (APE) on enteric and spinal sensory neurons.

METHODS

Using Ca²⁺ and fast potentiometric imaging, we recorded the responses of guinea-pig and human submucous and guinea-pig dorsal root ganglion (DRG) neurons to microejection of low (<3 kDa) and high (≥3 kDa) molecular weight APEs of birch, ragweed, and hazel. Histamine was determined pharmacologically and by mass spectrometry (LC-MS/MS).

KEY RESULTS

Birch APE_<3kDa evoked strong [Ca⁺² ]_i signals in the vast majority of guinea-pig DRG neurons, and in guinea-pig and human enteric neurons. The effect of birch APE_≥3kDa was much weaker. Fast neuroimaging in human enteric neurons revealed an instantaneous spike discharge after microejection of birch, ragweed, and hazel APE_<3kDa [median (interquartile range) at 7.0 Hz (6.2/9.8), 5.7 Hz (4.4/7.1), and 8.4 Hz (4.3/12.5), respectively]. The percentage of responding neurons per ganglion were similar [birch 40.0% (33.3/100.0), ragweed 50.8% (34.4/85.6), and hazel 83.3% (57.1/100.0)]. A mixture of histamine receptor (H1-H3) blockers significantly reduced nerve activation evoked by birch and ragweed APEs_<3kDa , but was ineffective on hazel. Histamine concentrations in ragweed, birch and hazel APE's < 3 kDa were 0.764, 0.047, and 0.013 μM, respectively.

CONCLUSIONS

Allergen-free APEs from birch, ragweed, and hazel evoked strong nerve activation. Altered nerve-immune signaling as a result of severe pollen exposure could be a pathophysiological feature of allergic and non-allergic gut inflammation.

Antibiotics in the pathogenesis of diabetes and inflammatory diseases of the gastrointestinal tract

Antibiotic use is increasing worldwide. However, the use of antibiotics is clearly associated with changes in gut microbiome composition and function, and perturbations have been identified as potential environmental risk factors for chronic inflammatory disorders of the gastrointestinal tract. In this Review, we examine the association between the use of antibiotics and the onset and development of both type 1 and type 2 diabetes, inflammatory bowel disease, including ulcerative colitis and Crohn's disease, as well as coeliac disease and eosinophilic oesophagitis. We discuss the key findings of epidemiological studies, provide mechanistic insights into the pathways by which the gut microbiota might contribute to these diseases, and assess clinical trials investigating the effects of antibiotics. Such studies indicate that antibiotic exposures, varying in type, timing and dosage, could explain differences in disease risk. There seems to be a critical window in early life in which perturbation of the microbiome has a substantial effect on disease development. Identifying the antibiotic-perturbed gut microbiota as a factor that contributes to the pathophysiology of these inflammatory disorders might stimulate new approaches to prevention, diagnosis and treatment.

Nature with Nurture: the Role of Intrinsic Genetic and Extrinsic Environmental Factors on Eosinophilic Esophagitis

PURPOSE OF REVIEW

As the rising prevalence and incidence of eosinophilic esophagitis (EoE) has quickly outpaced the rate of esophageal biopsies, particularly in Westernized countries, several studies have suggested a link between intrinsic genetic and extrinsic environmental risk factors and the development, presentation, and diagnosis of EoE. This review aims to critically assess existing studies describing the role of the environment on the development, symptomatic presentation, and diagnosis of this recently recognized chronic immune-mediated disease.

RECENT FINDINGS

We present and critically evaluate the working hypotheses and supportive studies thus far on environmental factors on EoE, describe sources of potential bias in diagnosis due to socioeconomic factors and thus undermining studies of EoE etiology, and highlight opportunities for future research. As genetics alone do not explain the rapid rise of EoE, we must look to environmental, or extrinsic, factors both in the early-life period which shape the development of the gut microbiome, as well as later life contributing to diagnosis of this new disease. Future etiologic studies linking risk factors to EoE development in individual patients are needed.

Primary eosinophilic gastrointestinal disorders and allergy: Clinical and therapeutic implications

Primary eosinophilic gastrointestinal disorders (EGID) are increasingly prevalent, immune‐mediated, chronic conditions which primarily affect pediatric and young adult patients, leading to substantial disease burden, and poor quality of life. EGID may either involve single portions of the gastrointestinal tract (i.e., esophagus, stomach, small bowel, and colon) or a combination. Their strong association with allergic disorders has been recently recognized, and although their shared pathophysiological basis remains partly elusive, this feature greatly impacts the diagnostic and treatment work‐up. We herein critically discuss the current knowledge on the association of EGID and allergic disorders, including atopic dermatitis, allergic rhinitis, allergic asthma, and food or drug allergy. In particular, we reviewed the literature focusing on their epidemiology, pathophysiological basis and mechanisms, and diagnostic strategies. Finally, we discuss the currently ongoing clinical trials targeting EGID and allergic diseases, including, among others the monoclonal antibodies dupilumab, mepolizumab, benralizumab, and lirentelimab.

EoE CONNECT, the European Registry of Clinical, Environmental, and Genetic Determinants in Eosinophilic Esophagitis: rationale, design, and study protocol of a large-scale epidemiological study in Europe

BACKGROUND

The growing prevalence of eosinophilic esophagitis (EoE) represents a considerable burden to patients and health care systems. Optimizing cost-effective management and identifying mechanisms for disease onset and progression are required. However, the paucity of large patient cohorts and heterogeneity of practice hinder the defining of optimal management of EoE.

METHODS

EoE CONNECT is an ongoing, prospective registry study initiated in 2016 and currently managed by EUREOS, the European Consortium for Eosinophilic Diseases of the Gastrointestinal Tract. Patients are managed and treated by their responsible specialists independently. Data recorded using a web-based system include demographic and clinical variables; patient allergies; environmental, intrapartum, and early life exposures; and family background. Symptoms are structurally assessed at every visit; endoscopic features and histological findings are recorded for each examination. Prospective treatment data are registered sequentially, with new sequences created each time a different treatment (active principle, formulation, or dose) is administered to a patient. EoE CONNECT database is actively monitored to ensure the highest data accuracy and the highest scientific and ethical standards.

RESULTS

EoE CONNECT is currently being conducted at 39 centers in Europe and enrolls patients of all ages with EoE. In its aim to increase knowledge, to date EoE CONNECT has provided evidence on the effectiveness of first- and second-line therapies for EoE in clinical practice, the ability of proton pump inhibitors to induce disease remission, and factors associated with improved response. Drug effects to reverse fibrous remodeling and endoscopic features of fibrosis in EoE have also been assessed.

CONCLUSION

This prospective registry study will provide important information on the epidemiological and clinical aspects of EoE and evidence as to the real-world and long-term effectiveness and safety of therapy. These data will potentially be a vital benchmark for planning future EoE health care services in Europe.

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.

Immunogenetic, Molecular and Microbiotic Determinants of Eosinophilic Esophagitis and Clinical Practice-A New Perspective of an Old Disease

Eosinophilic oesophagitis (EoE) is a chronic, allergic disease associated with a T-lymphocyte response inducing esophageal eosinophilic infiltration in the esophagus. Inflammation and tissue fibrosis are responsible for the main clinical symptoms such as food impaction and dysphagia. The etiopathogenesis is multifactorial in which genetic and environmental factors coexist. The most common trigger is a non-IgE-mediated food allergy to milk, wheat, egg, soybean, nuts, fish, and seafood. The second factor we focus on is the contribution of genetic variation to the risk of EoE, describing the expression profile of selected genes associated with eosinophilic oesophagitis. We raise the topic of treatment, aiming to eliminate inflammation through an elimination diet and/or use of pharmacologic therapy with the use of proton pump inhibitors or steroids and endoscopic procedures to dilate the esophagus. We demonstrate that early diagnosis and effective treatment prevent the development of food impaction and decreased quality of life. The increasing presence of EoE requires bigger awareness among medical specialists concerning clinical features, the course of EoE, diagnostic tools, and management strategies.

Insights into the Implications of Coexisting Type 2 Inflammatory Diseases

The role of type 2 inflammation in the pathogenesis of certain human diseases is an area of active investigation. Certain asthma, atopic dermatitis, eosinophilic esophagitis, and chronic rhinosinusitis phenotypes are characterized by a Th2 predominant inflammatory pathway and are frequently associated with comorbid conditions in patients. The purpose of this article is to review the evidence behind concurrent Th2-mediated diseases and explore how the presence of these comorbid conditions affect patient and disease outcomes.

The Role of the Environment in Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic immune-mediated disease clinicopathologically characterized by esophageal dysfunction. EoE is characterized by eosinophilic histologic inflammation indistinguishable from other atopic diseases such as asthma, eczema, or allergic rhinitis, which often co-occur in patients with EoE. This suggest a possible shared pathophysiology and triggers in the development of EoE with other atopic conditions. Although the evidence of EoE being linked to exposure to allergenic foods is strong, the connection between EoE and aeroallergens is less understood. In this review, we will discuss clinical, epidemiological, and animal studies that investigate how environmental allergens influence the clinical manifestations of EoE and its seasonality. It is also known that the developing immune system is significantly shaped by early-life exposures, pollution, climate change, and those factors that are known to influence development of asthma. We therefore also describe the evidence for and the gaps in our knowledge of the role of early-life exposures, pollution, and climate change in the development of EoE.

Early life antibiotics and childhood gastrointestinal disorders: a systematic review

BACKGROUND

In adults, there is increasing evidence for an association between antibiotic use and gastrointestinal (GI) disorders but in children, the evidence is scarce.

OBJECTIVE

Assess the association between exposure to antibiotics in the first 2 years of life in term born children and the presence of chronic GI disorders later in childhood.

DESIGN

For this systematic review the MEDLINE, Embase, WHO trial register and Web of Science were systematically searched from inception to 8 June 2020. Title and abstract screening (n=12 219), full-text screening (n=132) as well as the quality assessment with the Newcastle-Ottawa Scale were independently performed by two researchers.

MAIN OUTCOME MEASURES

The association between antibiotics and inflammatory bowel disease (IBD) (n=6), eosinophilic oesophagitis (EoE) (n=5), coeliac disease (CeD) (n=6), infantile colics (n=3), functional constipation (n=2), recurrent abdominal pain, regurgitation, functional diarrhoea and infant dyschezia were examined.

RESULTS

Twenty-two studies were included, 11 cohort and 11 case-control studies. A best evidence synthesis showed strong evidence for an association between antibiotic exposure in the first 2 years of life and the presence of IBD, and CeD during childhood. Moderate evidence was found for an association with EoE and no association with functional constipation in the first year of life. There was insufficient evidence for the other studied disorders.

CONCLUSIONS

The use of antibiotics in early life may increase the risk of GI disorders later in life. Further studies are necessary to unravel the underlying mechanisms and determine potential preventive measures. Meanwhile judicious use of antibiotics in early childhood is highly warranted.

PROSPERO REGISTRATION NUMBER

PROSPERO CRD42019132631.

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.

Epidemiology and risk factors for eosinophilic esophagitis: lessons for clinicians

INTRODUCTION

The rapid expansion in the epidemiology of eosinophilic esophagitis (EoE) is being documented, along with cumulative research assessing environmental exposures associated with EoE and susceptibility due to genetic variants.

AREAS COVERED

Incidence rates for EoE of 5-10 new cases per 100,000 inhabitants annually have shown an increase in recent reports of up to 20 in some countries; the highest prevalence being reported for Europe and North America, where EoE now affects more than 1 out of 1,000 people. EoE has been shown to be associated with several disorders, Th2-mediated atopies being the most common. Patients with EoE exhibit increased frequency of asthma, allergic rhinitis and eczema, and EoE has been considered as a late component of the atopic march. Risk variants in TSLP, CAPN14 and LRCC32 genes, among others, have all been related to EoE, and interact with prenatal and early life exposure potentially modifying abundance and composition of gut microbiome. Dysregulated interactions between bacteria and mucosal immunity emerge as leading causes of EoE.

EXPERT OPINION

The expanding epidemiology of EoE, the resources needed and subsequent increasing healthcare costs require additional effort to optimize cost-effective management and unveil mechanisms that enhance the development of future preventive strategies.

Early life factors are associated with risk for eosinophilic esophagitis diagnosed in adulthood

Early life exposures have been associated with pediatric eosinophilic esophagitis (EoE), but it is unknown if a similar association is present in adults. We aimed to assess the association between early life risk factors and development of EoE in adulthood. To do this, we conducted a case-control study which was nested within a prospective cohort study of adults undergoing outpatient endoscopy. Cases of EoE were diagnosed per consensus guidelines; controls did not meet these criteria. Subjects and their mothers were contacted to collect information on four key early life exposures: antibiotics taken during the first year of life, Cesarean delivery, preterm delivery (≤37 weeks' gestation), and neonatal intensive care unit (NICU) admission. We calculated the odds of EoE given in each exposure and assessed agreement between subjects and their mothers. For the 40 cases and 40 controls enrolled, we observed a positive association between each of the early life exposures and development of EoE (antibiotics in infancy, OR = 4.64, 95% CI = 1.63-13.2; Cesarean delivery, OR = 3.08, 95% CI = 0.75-12.6; preterm delivery, OR = 2.92, 95% CI = 0.71-12.0; NICU admission, OR = 4.00, 95% CI = 1.01-15.9). Results were unchanged after adjusting for potential confounders, though only early antibiotic use had CIs that did not cross 1.0. Moderate to strong agreement was observed between 54 subject-mother pairs (antibiotics, K = 0.44, P = 0.02; Cesarean delivery, K = 1.0, P < 0.001; preterm delivery, K = 0.80, P < 0.001; NICU, K = 0.76, P < 0.001). In sum, antibiotics in infancy was significantly associated with increased risk of EoE diagnosed in adulthood, while positive trends were seen with other early life factors such as Cesarean delivery, preterm delivery, and NICU admission. This may indicate persistent effects of early life exposures and merits additional study into conserved pathogenic mechanisms.

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.

Eosinophilic esophagitis: early diagnosis is the key

Eosinophilic esophagitis (EoE) is a disorder which affects all ages, from infancy through adulthood. It typically affects atopic individuals (Table 1) and is a chronic allergic disorder, with foods ubiquitous in the diet being the most described trigger of this isolated eosinophilic inflammation of the esophagus in both adults and children. This inflammatory process leads to esophageal symptoms such as dysphagia and feeding intolerance. In this review, we provide a brief overview of the current state of EoE therapy and symptomatology and then try to make the case for early diagnosis and treatment to prevent some of the long-term consequences of esophageal inflammation.

Eosinophilic esophagitis in children: doubts and future perspectives

Background

Eosinophilic esophagitis (EoE) is a chronic immune-mediated inflammatory disorder and represents the leading cause of food impaction. The pathogenesis of EoE is the result of an interplay between genetic, environmental and host immune system factors. New therapeutic approaches for EoE have been proposed. In this manuscript we review the current evidence regarding EoE management in pediatric age, with a particular focus on new findings related to the efficacy and safety of monoclonal antibodies.

Main body

Conventional therapies have failed in treating some patients with EoE, which then requires aggressive procedures such as esophageal dilatation. The most effective available medical therapy for EoE is swallowed topic corticosteroids (fluticasone propionate and budesonide), which have two main drawbacks: they are related to well-known adverse effects (especially in the paediatric population), and there are not enough long-term data to confirm that they are able to reverse the remodelling process of the esophageal mucosa, which is the major cause of EoE symptoms (including dysphagia, abdominal pain, nausea, obstruction, perforation and vomiting). The monoclonal antibodies appear to be an interesting therapeutic approach. However, the studies conducted until now have shown substantial histological improvement not coupled with significant clinical improvements and no significant relationship between a decreasing number of eosinophils and clinical symptoms, highlighting the importance in the pathogenesis of EoE of cells such as T-helper cells, mast cells, B cells, epithelial cells and natural killer cells.

Conclusions

Monoclonal antibodies targeting a signal involved in the pathogenesis of EoE may not break the complex self-propagating inflammatory activation responsible for perpetuation of the inflammatory response and the development of symptoms and complications. We speculate that combined biological therapies targeting more than one molecule or cell may provide better results, with conventional therapies potentially enhancing the effects of antibodies. However, further studies should aim to find the best therapeutic approach to target the cells involved in the remodelling process and to reverse the histological changes in this complex clinical condition.

Epithelial origin of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic, allergen-driven inflammatory disease of the esophagus characterized predominantly by eosinophilic inflammation, leading to esophageal dysfunction. Converging data have placed the esophageal epithelium at the center of disease pathogenesis. In particular, the main EoE disease susceptibility loci at 2p23 and 5p22 encode for gene products that are produced by the esophageal epithelium: the intracellular protease calpain 14 and thymic stromal lymphopoietin, respectively. Furthermore, genetic and functional data establish a primary role for impaired epithelial barrier function in disease susceptibility and pathoetiology. Additionally, the EoE transcriptome, a set of genes dysregulated in the esophagi of patients with EoE, is enriched in genes that encode for proteins involved in esophageal epithelial cell differentiation. This transcriptome has a high proportion of esophagus-specific epithelial genes that are notable for the unexpected enrichment in genes encoding for proteases and protease inhibitors, as well as in IL-1 family genes, demonstrating a previously unappreciated role for innate immunity responses in the esophagus under homeostatic conditions. Among these pathways, basal production of the serine protease inhibitor, Kazal-type 7 (SPINK7) has been demonstrated to be part of the normal differentiation program of esophageal epithelium. Profound lost expression of SPINK7 occurs in patients with EoE and is sufficient for unleashing increased proteolytic activity (including urokinase plasminogen activator), impaired barrier function, and production of large quantities of proinflammatory and proallergic cytokines, including thymic stromal lymphopoietin. Collectively, we put forth a model in which the esophagus is normally equipped as an anti-inflammatory sensing organ and that defects in this pathway, mediated by epithelial protease/protease inhibitor imbalances, unleash inflammatory responses resulting in disorders, such as EoE.

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.

Early Infant Risk Factors for Pediatric Eosinophilic Esophagitis

OBJECTIVES

Eosinophilic esophagitis (EoE) is an inflammatory, atopic disease of the esophagus without a clear etiology. Our objective was to identify exposures and conditions in early infancy associated with the development of EoE.

METHODS

A case-control study was performed using the Military Health System Database. Subjects diagnosed with EoE from October 2008 to September 2015 were matched 1:2 on age and sex. Early infant risk factors from the first 6 months of life were investigated.

RESULTS

A total of 1410 cases with EoE were matched to 2820 controls. The median (interquartile range) age at diagnosis of EoE was 4.2 years (2.1-7.2) and 68.7% were boys. Proton pump inhibitors (adjusted odds ratio [aOR], 2.73; 95% confidence interval [CI] 1.93-3.88), histamine-2 receptor antagonists (aOR, 1.64; 95% CI 1.27-2.13), and antibiotics (aOR, 1.31; 95% CI 1.10-1.56) were associated with EoE. Prematurity (aOR, 1.46; 95% CI 1.12-1.89) and early manifestations of atopic disease such as milk protein allergy (aOR, 2.37; 95% CI 1.26-4.44) and eczema (aOR, 1.97; 95% CI 1.64-2.36) were related to increased odds for EoE. Erythema toxicum in infancy was strongly associated with a diagnosis of EoE (aOR 3.52; 95% CI 1.03-12.04). Infants with feeding difficulty (aOR, 1.45; 95% CI 1.18-1.77) and gastroesophageal reflux disease (aOR, 1.79; 96% CI 1.43-2.26) were also at increased risk for EoE.

CONCLUSIONS

Acid-blocking medications and antibiotics during infancy were associated with later diagnosis of EoE. Erythema toxicum neonatorum, an eosinophilic immune phenomenon, was strongly associated with EoE. Identifying early infant risk factors for EoE may help to risk stratify the need for endoscopy.

Environmental factors and eosinophilic esophagitis

The incidence and prevalence of eosinophilic esophagitis (EoE) have markedly increased over the past 2 decades, outpacing increased detection of the disease. Although genetic susceptibility markers for EoE have begun to be elucidated, the rate at which EoE has increased in incidence suggests environmental factors predominate. Despite many advances in understanding of the pathogenesis of EoE, the cause of EoE is unknown. This article reviews the emerging data related to environmental risk factors for EoE. Many of these environmental factors are rooted in the theoretical framework of the hygiene hypothesis, specifically mediation of disease development through dysbiosis. Other hypotheses are based on associations that have been observed in studies of non-EoE allergic disease. We describe the evidence that early-life exposures, including antibiotic use, acid suppression, and cesarean delivery, can increase the risk of disease. We also describe the evidence that infectious agents, such as Helicobacter pylori, are inversely associated with disease. Current evidence on geographic risk factors, such as population density, climate zone, and seasonality, is reviewed. We also describe behavioral factors that have been evaluated. Limitations of the existing research are discussed, and recommendations for future areas of research, including assessment of gene-environment interaction, are presented.

Treatment of eosinophilic esophagitis in the pediatric patient: an evidence-based approach

Eosinophilic esophagitis (EoE) is a unique form of non-IgE-mediated food allergy characterized by esophageal eosinophilic infiltration that commonly causes dysphagia and food impaction in children and adolescents. Assessing the efficacy of dietary restrictions or drug therapies to achieve clinical and histologic resolution of EoE through randomized controlled trials and meta-analyses has resulted in new evidence-based guidelines. Avoiding food triggers is the only therapy targeting the cause of the disease. None of the currently available food allergy tests adequately predict food triggers for EoE. Exclusively feeding with an amino acid-based elemental diet and empiric six-food elimination diet (avoiding the six foods most commonly related with food allergy) has consistently provided the best cure rates, but their high level of restriction and need for multiple endoscopies are deterrents for implementation. Simpler and less restrictive empirical methods, like a four-food (milk, gluten-containing cereals, egg, legumes) or a two-food (milk and gluten) elimination diet, show encouraging results. Proton pump inhibitors are currently a first-line treatment, achieving histological remission and improvement of symptoms in 54.1 and 64.9% of pediatric EoE patients, respectively. The efficacy of topical corticosteroids in EoE assessed in several trials and summarized in meta-analyses indicates that budesonide and fluticasone propionate are significantly superior to placebos, both in decreasing eosinophil mucosal infiltration and in relieving symptoms. Owing to differences in drug delivery, viscous budesonide formulas seem to be the best pharmacological therapy for EoE.

CONCLUSION

Applying evidence-based therapies and a practical management algorithm provide an effective control of EoE. What is Known: • Eosinophilic esophagitis (EoE) now constitutes the main cause of dysphagia and food impaction in children, adolescents, and young adults. • Its chronic course and frequent progression to subepithelial fibrosis leading to strictures and narrow-caliber esophagus indicate the need for treatment. What is New: • Therapeutic goals in children with EoE include resolution of esophageal symptoms, to cure esophageal inflammation (mucosal healing) and restore a proper esophageal caliber in case of fibrostenotic endoscopic findings. Avoiding iatrogenic drug effects and nutritional deficiencies, as well as maintaining an adequate quality of life, is also essential. • Novel evidence-based guidelines, endorsed by several European scientific societies, incorporate recent advances in knowledge from several randomized controlled trials and systematic reviews to provide the best standard of care to pediatric patients, by following simple management algorithms.

Prenatal, intrapartum, and postnatal factors are associated with pediatric eosinophilic esophagitis

BACKGROUND

Multiple lines of evidence point to the potential importance of early-life environmental factors in the rapid increase in the incidence of eosinophilic esophagitis (EoE), but potential exposures have not been extensively studied.

OBJECTIVE

We sought to assess the association between prenatal, intrapartum, and postnatal factors and the development of pediatric EoE using a case-control study.

METHODS

Patients with EoE were recruited from an existing registry at Cincinnati Children's Hospital Medical Center (CCHMC). Population-based community control subjects were identified from a separate CCHMC registry. Mothers of study subjects were contacted and completed a Web-based questionnaire. Crude and adjusted models were used to estimate associations.

RESULTS

Mothers of 127 cases and 121 control subjects were included. We observed a positive association between several early-life factors and EoE, including prenatal (maternal fever: adjusted odds ratio [aOR], 3.18; 95% CI, 1.27-7.98; preterm labor: aOR, 2.18; 95% CI, 1.06-4.48), intrapartum (cesarean delivery: aOR, 1.77; 95% CI, 1.01, 3.09), and infancy (antibiotic use: aOR, 2.30; 95% CI, 1.21-4.38; use of an acid suppressant: aOR, 6.05; 95% CI, 2.55-14.40) factors. We observed an inverse association between having a furry pet in infancy and EoE (aOR, 0.58; 95% CI, 0.34-0.97). No associations were observed for breast-feeding or maternal multivitamin or folic acid supplement use.

CONCLUSION

Early-life factors, including maternal fever, preterm labor, cesarean delivery, and antibiotic or acid suppressant use in infancy, were associated with risk of pediatric EoE; having a pet in the home was protective. These results add to growing evidence that implicate early-life exposures in EoE pathogenesis.

Pathophysiology of Eosinophilic Esophagitis

Eosinophilic esophagitis is an emerging disease that is distinguished from gastroesophageal reflux disease by the expression of a unique esophageal transcriptome and the interplay of early life environmental factors with distinct genetic susceptibility elements at 5q22 (TSLP) and 2p23 (CAPN14). Rare genetic syndromes have uncovered the contribution of barrier disruption, mediated in part by defective desmosomes and dysregulated transforming growth factor beta production and signaling, to eosinophilic esophagitis pathophysiology. Experimental modeling has defined a cooperative role of activated eosinophils, mast cells, and the cytokines IL-5 and IL-13, mediated by allergic sensitization to multiple foods. Understanding these processes is opening the way to better treatment based on disrupting allergic inflammatory and type 2 cytokine-mediated responses, including anti-cytokine therapeutics and dietary therapy.

Epidemiology and Natural History of Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) has emerged over the past 2 decades as a major cause of upper gastrointestinal morbidity. Over this time, the epidemiology of EoE has also rapidly evolved. EoE has transformed from a rare case-reportable condition to disease that is commonly encountered in the gastroenterology clinic, hospital emergency room, and endoscopy suite. The incidence and prevalence are increasing at rates that outpace increased disease recognition. Current incidence estimates range from 5 to 10 cases per 100,000, and current prevalence estimates range from 0.5 to 1 case per 1000. We review the data and potential reasons behind this increase, examine risk factors, and identify important areas for research into disease etiology. The article also discusses the progression of EoE from an inflammatory to fibrostenotic phenotype. An accurate view of the natural history of EoE is central to discussions with patients regarding disease prognosis and decisions about long-term use of medical, endoscopic, and diet therapies. Progressive remodelling appears to be gradual, but not universal, and the duration of untreated disease is the best predictor of stricture risk. Ultimately, prospective, long-term outcome studies focusing on multiple aspects of disease activity are needed to fully understand the natural history of EoE.

Eosinophilic Esophagitis: Pathophysiology and Definition

Eosinophilic esophagitis is an adaptive immune response to patient-specific antigens, mostly foods. Eosinophilic esophagitis is not solely IgE-mediated and is likely characterized by Th2 lymphocytes with an impaired esophageal barrier function. The key cytokines and chemokines are thymic stromal lymphopoeitin, interleukin-13, CCL26/eotaxin-3, and transforming growth factor-β, all involved in eosinophil recruitment and remodeling. Chronic food dysphagia and food impactions, the feared late complications, are related in part to dense subepithelial fibrosis, likely induced by interleukin-13 and transforming growth factor-β.

Early-life environmental exposures interact with genetic susceptibility variants in pediatric patients with eosinophilic esophagitis

BACKGROUND

Although eosinophilic esophagitis (EoE) is associated with certain gene variants, the rapidly increasing incidence of EoE suggests that environmental factors contribute to disease development.

OBJECTIVE

We tested for gene-environment interaction between EoE-predisposing polymorphisms (within TSLP, LOC283710/KLF13, CAPN14, CCL26, and TGFB) and implicated early-life factors (antibiotic use in infancy, cesarean delivery, breast-feeding, neonatal intensive care unit [NICU] admission, and absence of pets in the home).

METHODS

We conducted a case-control study using hospital-based cases (n = 127) and control subjects representative of the hospital catchment area (n = 121). We computed case-only interaction tests and in secondary analyses evaluated the combined and independent effects of genotype and environmental factors on the risk of EoE.

RESULTS

Case-only analyses identified interactions between rs6736278 (CAPN14) and breast-feeding (P = .02) and rs17815905 (LOC283710/KLF13) and NICU admission (P = .02) but not with any of the factors examined. Case-control analyses suggested that disease risk might be modifiable in subjects with certain gene variants. In particular, breast-feeding in those with the susceptibility gene variant at rs6736278 (CAPN14) reduced the risk of EoE (adjusted odds ratio, 0.08; 95% CI, 0.01-0.59). Admission to the NICU in those without the susceptibility gene variant at rs17815905 (LOC283710/KLF13) significantly increased the risk of having disease (adjusted odds ratio, 4.83; 95% CI, 1.49-15.66).

CONCLUSIONS

The interplay of gene (CAPN14 and LOC283710/KLF13) and early-life environment factors (breast-feeding and NICU admission) might contribute to EoE susceptibility.

Association between atopic manifestations and eosinophilic esophagitis: A systematic review and meta-analysis

BACKGROUND

Eosinophilic esophagitis (EoE) has repeatedly been associated with atopic manifestations, which are reported more frequently in these patients than in the general population.

OBJECTIVE

To systematically assess the evidence and strength of the associations between EoE and atopy.

METHODS

We performed a systematic search of the MEDLINE, EMBASE, and SCOPUS databases for case-control studies comparing the frequency of atopic diatheses among patients with EoE and control subjects representing the general population without EoE. Using random-effects meta-analyses, we calculated summary estimates, including 95% confidence intervals (CIs), for bronchial asthma, atopic rhinitis, and eczema. Publication bias risks were assessed by means of funnel plot analysis and specific statistical tests.

RESULTS

Of the 2,954 references identified, data were collected from 21 studies, including a total of 53,542 patients with EoE and 54,759 controls. The criteria for defining a diagnosis of atopy in patients with EoE or controls was not structurally considered in most of the studies. Overall, allergic rhinitis was significantly more common among patients with EoE compared with control subjects (odds ratio [OR], 5.09; 95% CI, 2.91-8.90; I² = 86.7%) as were bronchial asthma (OR, 3.01; 95% CI, 1.96-4.62; I² = 84.5%) and eczema (OR, 2.85; 95% CI, 1.87-4.34; I² = 57.1%). Food allergies and other atopic conditions were also assessed. No significant publication bias was found for studies dealing with allergic rhinitis and eczema in EoE.

CONCLUSION

Despite pointing to a significant association between atopy and EoE, most of the studies provided no normalized diagnostic criteria for atopy. Further research should provide clear and standardized definitions of such conditions.

TRIAL REGISTRATION

www.crd.york.ac.uk/PROSPERO Trial Identifier: CRD42016036161.

Eosinophilic esophagitis: What can we learn from Crohn's disease?

Eosinophilic esophagitis (EoE) is an emerging esophageal inflammatory disorder affecting children and young adults. As a relatively new disease, EoE is still burdened by frequent diagnostic and therapeutic pitfalls in clinical practice. This manuscript posits a number of similarities with Crohn's disease, which may help optimize EoE patient management. Commonalities include epidemiologic trends (Westernized diseases, rising incidence, early-life risk factors), diagnostic considerations (symptoms are poor predictors of disease activity, difficulties in disease activity assessment) and therapeutic issues (similar natural history and therapeutic goals, induction and maintenance phases, combination of drug and endoscopic treatment, potential drug interchangeability, long-term unsolved issues). Physicians devoted to EoE should learn from the extraordinary achievements fulfilled in Crohn's disease: increased disease awareness, multidisciplinary specialized clinics, structured childhood and transition programs, and an ongoing roadmap for personalized treatments, including genetic susceptibility, risk factors for progression, genotype-phenotype correlation, drug monitoring and microbial data.

Assessing Early Life Factors for Eosinophilic Esophagitis: Lessons From Other Allergic Diseases

OPINION STATEMENT

Few studies have been conducted to investigate possible early life determinants for eosinophilic esophagitis. An improved understanding of the etiologic factors implicated in disease development would further elucidate possible disease pathogenesis, inform therapeutic targets for disease treatment, and identify possible modifiable factors for disease prevention in genetically susceptible individuals. Although eosinophilic esophagitis is increasing in incidence and prevalence, the disease remains relatively rare, posing challenges for studying etiologic factors in disease development. Eosinophilic esophagitis is believed to be antigen-mediated, and most patients with EoE have concomitant atopic disease. In recent years, the evolution of our understanding of possible etiologic mechanisms in allergic disease has been informed by our understanding of how early life perturbations can lead to dysbiosis in the colonization of the microflora in the gastrointestinal tract and subsequent dysregulated immune development. Perturbations include factors such as antibiotic use, including prenatal, intra-antepartum, and infancy use of antibiotics, Cesarean delivery, preterm delivery, and neonatal intensive care admission. This article provides a review of these recent developments, as they relate to atopic disease, to inform future directions in the study of early life etiologic factors in the development of eosinophilic esophagitis.

The Role of Environmental Exposures in the Etiology of Eosinophilic Esophagitis: A Systematic Review

Eosinophilic esophagitis (EoE) is an emerging clinicopathologic entity defined by abnormal esophageal eosinophilic infiltration. Management of this disease is hampered by limited understanding of etiologic and controllable risk factors. The aim of this systematic review was to determine the environmental risk factors for EoE. We searched the PubMed, Web of Science, and EMBASE databases from January 1, 1950, through June 30, 2015. To identify additional relevant studies, we hand searched bibliographies of included articles. We limited the review to articles using human subjects and consisting of case reports, case series, cross-sectional and cohort studies, and clinical trials. Nineteen articles discuss the risk of environmental exposures on EoE and indicate that environment plays a large role in the etiology of EoE. Seasonal, geographic, and climate-based differences in disease prevalence have been reported, but the exact mediators of this process, possibly aeroallergens that vary over time and from place to place, remain elusive.