Role of Endoscopy in Diagnosis and Management of Pediatric Eosinophilic Esophagitis

Prevalence and Costs of Esophageal Strictures in the United States

BACKGROUND & AIMS

Esophageal strictures are a leading cause of dysphagia, but data regarding the epidemiology of esophageal strictures are limited. This study aimed to investigate the prevalence, health care utilization, and financial burden of esophageal strictures in the United States.

METHODS

We performed a retrospective cohort study using 2 large national insurance claims databases (MarketScan and Medicare). Using International Classification of Diseases-9 and -10 diagnostic codes, annual prevalence was calculated for both cohorts overall, and stratified by age and sex strata. Most common diagnostic and procedural codes associated with esophageal strictures were extracted and analyzed to estimate health care utilization. Direct annual medical costs of esophageal strictures were calculated.

RESULTS

The annual prevalence of esophageal strictures in MarketScan in 2021 was 203.14 cases/100,000 people, whereas the annual prevalence in Medicare cohort in 2017 was 1123.47 cases/100,000. Although rates were relatively stable over time, esophageal stricture prevalence increased with advancing age. No prevalence differences were noticed between males and females. Gastroesophageal reflux disease/erosive esophagitis was the top diagnostic code associated with esophageal strictures, although an increase in the proportion of eosinophilic esophagitis codes was noted over time. Esophageal dilation codes were present in ∼50% of stricture cases. The total health care costs associated with esophageal strictures were estimated at $1.39 billion in 2017.

CONCLUSIONS

Esophageal strictures are common, affecting between 1/100 and 1/1000 patients in the United States, with the highest rates seen in patients aged 75 years and older. Accordingly, strictures have a significant financial burden on the health care system, with costs greater than $1 billion annually.

Oesophageal wall thickness assessment at endoscopic ultrasound in children and adolescents with eosinophilic oesophagitis: a case-control study

PURPOSE

Eosinophilic oesophagitis (EoE) is a chronic immune-mediated disease, and an endosonographic evaluation may help the diagnosis. The main objectives of this study were to measure the thickness of the oesophageal wall using a radial endoscopic ultrasound (EUS), mucosa/submucosa (MSM), muscularis propria (MP) and mucosa to muscularis propria (MMP); to compare these measurements between patients with and without EoE; to correlate them with the Endoscopic Reference Score (EREFS); and to evaluate the diagnostic accuracy of these measurements.

METHODS

Children and adolescents (aging from 4 to 17 years) were evaluated in this prospective cross-sectional study. A radial EUS at 12 MHz frequency was used, and EREFS was employed to grade macroscopic findings. Accuracy of the measurements for the diagnosis of EoE was assessed by receiver operating characteristics (ROC) curve.

RESULTS

Twenty-six (19 M/7 F) patients (median age 10.83 years, range 5.65-17.46) were evaluated. EoE was diagnosed in 6 patients. The mean (and SD) oesophageal wall thicknesses in the distal oesophagus in millimetres in groups with and without EoE, respectively, were: MSM 1.07 (0.44) and 1.11 (0.33); MP 0.67 (0.25) and 0.60 (0.19); and MMP 1.73 (0.46) and 1.72 (0.32). Mid-oesophagus: MSM 1.16 (0.34) and 1.15 (0.34); MP 0.63 (0.16) and 0.60 (0.2); and MMP 1.79 (0.41) and 1.74 (0.34). In the ROC curve, the distal MP layer thickness presented better discriminative performance, with an area under the curve of 0.61 (95% CI 0.28-0.93) at 0.73 mm cut-off (66.67% sensitivity, 80% specificity, likelihood ratios of 3.33 for positive and 0.42 for negative test).

CONCLUSION

The evaluation of oesophageal thickness measurements by EUS is not useful for diagnosing EoE.

Salivary microRNAs in pediatric eosinophilic esophagitis

Background: Diagnosis and management of eosinophilic esophagitis (EoE) occur via esophagogastroduodenoscopy with tissue biopsy. Objective: We sought to determine if salivary microribonucleic acid (miRNA) levels could differentiate children with EoE, serving as a noninvasive biomarker. Methods: Saliva was collected from children undergoing esophagogastroduodenoscopy (N = 291). miRNA analysis was conducted on 150 samples: EoE (n = 50), no pathologic alteration (n = 100). RNA was quantified with high throughput sequencing and aligned to build hg38 of the human genome using sequencing and alignment software. Quantile normalized levels of robustly expressed miRNAs (raw counts > 10 in 10% of samples) were compared across EoE and non-EoE groups with Wilcoxon rank sum testing. miRNA biomarker candidates were selected based on variable importance projection (VIP) scoring with partial least squared discriminant analysis (VIP > 1.5). Ability of these miRNAs to differentiate EoE status was assessed via logistic regression. Putative biologic targets for the miRNA candidates were determined in miRNA pathway analysis software. Results: Of the 56 salivary miRNAs reliably detected, miR-205-5p displayed the largest difference between EoE and non-EoE groups (V = 1623, adjusted p = 0.029). Six miRNAs (miR-26b-5p, miR-27b-3p, Let-7i-5p, miR-142-5p, miR-30a-5p, miR-205-5p) displayed elevated VIP scores (>1.5) and were able to differentiate EoE samples on logistic regression analysis with 70% sensitivity and 68% specificity. These six miRNAs demonstrated significant enrichment for gene targets involved in valine, leucine, and isoleucine biosynthesis (p = 0.0012), 2-oxycarboxylic acid metabolism (p = 0.043), and steroid hormone biosynthesis (p = 0.048). Conclusions: Salivary miRNAs represent a noninvasive, biologically relevant measure that may aid disease monitoring of EoE.

Eosinophilic esophagitis: Comparison of clinical, endoscopic and histological scoring systems

Background Eosinophilic Esophagitis (EoE) has received increasing attention as a disease entity, and it is now recognized as an important disorder of the Upper Gastrointestinal Tract. Topical corticosteroids (tCS) are effective in clinical-pathological remission induction (RI) and remission maintenance (RM) of active EoE. With scoring systems, such as clinical (SDI), endoscopic (EREFS), and histological (EoEHSS) systems, EoE can be graded, and its disease activity can be assessed.

Objective To discover how closely results within each of the three scoring systems SDI, EREFS, and EoEHSS are correlated between initial diagnosis (ID), RI, and RM, and to determine how well scores from the three systems are intercorrelated at each time point.

Methods Retrospective cohort analysis of patients with active EoE was performed between 2006 and 2020, with follow-up for up to 6 years. SDI, EREFS and EoEHSS scores were recorded at ID, at RI, and in RM. Evaluation employed descriptive statistics, the Friedman test, and Bonferroni-corrected post hoc pairwise comparisons.

Results At RI 29 and at RM 19 EoE patients provided data. Significant correlations were found between EREFS and EoEHSS at RI and in RM. Pairwise comparisons showed significant differences between ID and RI for SDI, for EREFS, and for EoEHSS.

Conclusion The scoring systems tested did not show intercorrelation at ID. Comparison revealed significant differences for SDI, EREFS, and EoEHSS between the systems at ID und RI, but not in RM, during tCS treatment. These results underline the efficacy of tCS (at RI and RM) in the treatment of active EoE.

Determination of a treatment response threshold for the Eosinophilic Esophagitis Endoscopic Reference Score

BACKGROUND

Endoscopic features of eosinophilic esophagitis (EoE) are measured using the validated EoE Endoscopic Reference Score (EREFS); however, a threshold for treatment response has not been defined. We aimed to determine a cut-point for endoscopic response as measured by EREFS.

METHODS

We performed a secondary analysis of a randomized clinical trial comparing budesonide slurry with swallowed fluticasone multidose inhaler for initial treatment of EoE. In the parent trial, EREFS was determined before and after treatment (score range 0-9), as were histologic findings and dysphagia symptoms. We performed tabular, flexible trend, and dependent mixture analyses of measures of treatment response to select the best clinical EREFS threshold.

RESULTS

In the 111 included patients (mean age 39 years; 67 % male; 96 % white), an EREFS threshold of ≤ 2 was 80 % sensitive (95 % confidence interval [CI] 69 % to 88 %) and 83 % specific (95 %CI 67 % to 94 %) for histologic response (peak of < 15 eosinophils per high-power field). Flexible trend analysis and dependent mixture modeling similarly suggested that a threshold of ≤ 2 best captured the correlation of EREFS with histologic and symptomatic measures. Dependent mixture modeling found near-total membership in the response class at EREFS of 0 or 1 and > 75 % at EREFS of 2 or 3.

CONCLUSIONS

An EREFS of ≤ 2 was the best clinical threshold for endoscopic response to topical steroid treatment, and was consistent with clinical and histologic response. Therefore, future studies can report a binary outcome of endoscopic response when EREFS is 2 or less.

Proton Pump Inhibitor Therapy for Eosinophilic Esophagitis: History, Mechanisms, Efficacy, and Future Directions

Over the past decade, the role of proton pump inhibitor (PPI) medication has evolved from a diagnostic tool for Eosinophilic Esophagitis (EoE), by excluding patients with PPI responsive esophageal eosinophilia (PPI-REE), to a therapy for EoE. This transition resulted from the Updated International Consensus Diagnostic Criteria for Eosinophilic Esophagitis: Proceedings of the Appraisal of Guidelines for Research and Evaluation II (AGREE) Conference to support PPI therapy for EoE in children and adults. Additional recent advances have suggested a role for genetic variations that might impact response to PPI therapy for EoE. This review article will explore a brief background of EoE, the evolution of PPI therapy for EoE and its proposed mechanisms, efficacy and safety in children and adults, and considerations for future PPI precision medicine in patients with EoE.

Esophageal perforation in eosinophilic esophagitis: five cases in children

Background and study aims  Eosinophilic esophagitis (EoE) is a chronic immune disease with increasing incidence. It is clinically defined by symptoms of esophageal dysfunction and histologically by eosinophilic polynuclear cell infiltration of the esophageal mucosa. Symptoms are not specific and include gastroesophageal reflux disease (GERD), dysphagia, vomiting or dietary blockages. Chronic inflammation of the mucosa may lead to narrowing of the esophageal lumen responsible for impactions. Extraction procedures can be complicated by dissection and perforation. Rare spontaneous ruptures of the esophagus known as Boerhaave syndrome are also possible. We report five cases of esophageal perforation in children with EoE, three with spontaneous rupture and two after an endoscopic procedure. The evolution was favorable under medical treatment.

Nationwide Multicenter Study of Eosinophilic Esophagitis in Korean Children

PURPOSE

In East Asian countries, there are only a few epidemiologic studies of eosinophilic esophagitis (EoE) and no studies in children. We investigated the incidence and compared the clinical characteristics of EoE and eosinophilic gastroenteritis involving the esophagus (EGEIE) in Korean children.

METHODS

A total of 910 children, who had symptoms of esophageal dysfunction, from 10 hospitals in Korea were included. EoE was diagnosed according to diagnostic guidelines and EGEIE was diagnosed when there were >15 eosinophils in the esophagus per high power field (HPF) and >20 eosinophils per HPF deposited in the stomach and duodenum with abnormal endoscopic findings.

RESULTS

Of the 910 subjects, 14 (1.5%) were diagnosed with EoE and 12 (1.3%) were diagnosed with EGEIE. Vomiting was the most common symptom in 57.1% and 66.7% of patients with EoE and EGEIE, respectively. Only diarrhea was significantly different between EoE and EGEIE (p=0.033). In total, 61.5% of patients had allergic diseases. Exudates were the most common endoscopic findings in EoE and there were no esophageal strictures in both groups. The median age of patients with normal endoscopic findings was significantly younger at 3.2 years, compared to the median age of 11.1 years in those with abnormal endoscopic findings (p=0.004).

CONCLUSION

The incidence of EoE in Korean children was lower than that of Western countries, while the incidence of EGEIE was similar to EoE. There were no clinical differences except for diarrhea and no differences in endoscopic findings between EoE and EGEIE.

Current updates in diagnosis and management of eosinophilic esophagitis

Eosinophilic esophagitis is a relatively new, moderately-well understood disease. It is one of the leading causes of dysphagia in the pediatric population. Thought to be triggered by food ingestion, it is distinctly different from food allergies. Although endoscopy is required for diagnosis, this article will review warning signs and symptoms that aid with evaluation and diagnosis of this disease. Treatment modalities and management are evolving and more research is needed.

Correlation of endoscopic signs and mucosal alterations in children with eosinophilic esophagitis

BACKGROUND AND AIMS

In children with eosinophilic esophagitis (EoE), the relationship among the endoscopic reference score (EREFS), the histology scoring system (EoEHSS), and the peak eosinophil count (PEC) is incompletely described. Our aim was to determine the relationship among EREFS, EoEHSS, and PEC and develop a predictive model using components of EREFS and EoEHSS for EoE activity.

METHODS

We analyzed 189 paired EREFSs, EoEHSSs, and PECs. Active EoE (aEoE; n = 98) was defined as ≥15 eosinophils per high-power field and inactive EoE (iEoE; n = 91) as <15 eosinophils per high-power field. Spearman correlation (r) with Bonferroni correction was used to assess the relationship between EREFS, EoEHSS and PEC, and a back-transformed average Fisher test was used to determine the statistical significance of the differences. Receiver operating characteristic analysis was used to develop the predictive model.

RESULTS

The relationship between total EREFS and EoEHSS was modest (r = 0.61) but significantly stronger than the correlation between total EREFS and PEC (r = 0.55; P = .04). The relationship between total EREFS and EoEHSS tended to be stronger in aEoE compared with iEoE (r = 0.41 vs 0.24; P = .09). Compared with EREFS, EoEHSS had a significantly higher area under the curve (0.78 vs 0.92; P = .04) to predict aEoE. A combination of furrows, eosinophilic inflammation, basal cell hyperplasia, eosinophilic abscess, and dilated intercellular spaces had an area under the curve of 0.97, accuracy of 98%, sensitivity of 97%, and specificity of 98% to predict aEoE.

CONCLUSIONS

The endoscopy score modestly correlates with the histologic scoring system. Thus, the endoscopy score is not a reliable marker of tissue involvement in EoE. A panel of individual endoscopic and histologic signs hold promise to accurately predict EoE activity.

High-resolution manometry in diagnostics and evaluation of therapy effectiveness in patients with eosinophilic esophagitis - underestimated breakthrough or dead end?

Eosinophilic esophagitis (EoE) is a chronic disease with non-specific symptoms, among which dysphagia is a prevailing one. The observed increase of EoE rate, its chronic and recurrent character, as well as invasive follow-up examination (periodical panendoscopy with specimen collection for histopathology), compel optimization of both the diagnostics algorithm and disease monitoring through searching for new, unique methods and tools so far not applied, including high-resolution manometry (HRM). Mentioned investigations result from advances in comprehension of disease pathogenesis, in which it is suggested that development of a chronic inflammatory reaction of the esophageal wall may lead to consecutive fibrosis and motility disorders. In research published to date one manometric pattern characteristic for EoE was not obtained, whereas the obtained inconsistent and at times contradictory results do not correlate either with symptoms exacerbation or endoscopic scan. Numerous constraints of discussed studies as well as current knowledge in disease etiopathology and esophagus biomechanics prompt further investigation of HRM significance in diagnostics and therapy monitoring of patients with EoE.

Strategy for Food Reintroduction Following Empiric Elimination and Elemental Dietary Therapy in the Treatment of Eosinophilic Gastrointestinal Disorders

PURPOSE OF REVIEW

This review presents the available data regarding efficacy of nutritional therapy, highlighting clinical decision points and a strategy for reintroduction of foods following an elemental diet for treatment of eosinophilic gastrointestinal disorders.

RECENT FINDINGS

Elemental and empiric elimination diets are highly effective treatments for eosinophilic gastrointestinal diseases. Standardization in the reintroduction phase, after utilizing the diet for disease remission, is lacking. Clinicians are confronted with multiple challenges regarding the best practice for food reintroduction and identification of potential dietary triggers including order of foods being challenged and duration between endoscopic procedures. Individualization is required for preference and adherence to optimize quality of life and treatment success for this burdensome and life altering immune driven gastrointestinal disorder. Age specific concerns for children, teenagers, and adults should be assessed using a patient centric approach.

Epithelial-stromal crosstalk and fibrosis in eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a food allergen-induced inflammatory disorder. EoE is increasingly recognized as a cause of swallowing dysfunction, food impaction and esophageal stricture. Inflammation of the esophageal mucosa involves immune cell infiltrate, reactive epithelial changes and fibroblast activation, culminating in robust tissue remodeling toward esophageal fibrosis characterized by excess collagen deposition in the subepithelial lamina propria. Fibrosis contributes to a unique mechanical property of the EoE-affected esophagus that is substantially stiffer than the normal esophagus. There is a great need to better understand the processes behind esophageal fibrosis in order to foster improved diagnostic tools and novel therapeutics for EoE-related esophageal fibrosis. In this review, we discuss the role of esophageal inflammatory microenvironment that promotes esophageal fibrosis, with specific emphasis upon cytokines-mediated functional epithelial-stromal interplays, recruitment and activation of a variety of effector cells, and tissue stiffness. We then explore the current state of clinical methodologies to detect and treat the EoE-related esophageal stricture.

Pediatric Endoscopic Procedure Complications

PURPOSE OF REVIEW

This review summarizes the current body of research, define high-risk patients and endoscopic processes, and outline evidence-based countermeasures aimed at minimizing the incidence of complications during endoscopy in children.

RECENT FINDINGS

Significant complications of endoscopy requiring emergency department or inpatient admission in otherwise healthy children are unusual, but more common with therapeutic procedures; risk from procedures increases incrementally with preoperative coexisting conditions. Duodenal hematoma is predominantly a pediatric endoscopic complication and is more likely in hematology-oncology patients. Air embolism is a well-defined endoscopic retrograde cholangiopancreatography (ERCP) complication in adults and is likely to increase in children with increased performance of pediatric ERCP. Increased physician expertise is the most often proposed countermeasure, especially in the context of endoscopy complications in the higher-risk patient and procedure. Endoscopy in children remains a very safe group of procedures, although a more detailed understanding of risk factors and ideal training and practice organization is lacking.

Implementation of guidelines in eosinophilic esophagitis at an academic pediatric practice

Guidelines for eosinophilic esophagitis (EoE) require high-dose PPI (HD-PPI) trial to evaluate for PPI-responsive esophageal eosinophilia (PPI-REE) prior to EoE diagnosis and dedicated therapy. This involves a second esophagogastroduodenoscopy (EGD) to assess for PPI-REE. This study is to evaluate adherence to current guidelines in evaluation of PPI-REE and EoE. Retrospective review of new patients treated with HD-PPI after an index EGD showing >15 eos/hpf in esophageal biopsies. One hundred and eighty patients had an index EGD with esophageal eosinophilia of >15 eos/hpf. Of these, 97/180 (53.8%) received HD-PPI; remaining 83/180 were prescribed other interventions without a HD-PPI trial. Of the 180 patients, 143 (79.4%) patients returned for follow-up and of whom 96/143 (67.1%) underwent repeat EGD. Adherence to guidelines improves with time. Patients are vested in care.

Mucosal Impedance Measurements Differentiate Pediatric Patients With Active Versus Inactive Eosinophilic Esophagitis

BACKGROUND AND AIMS

Eosinophilic esophagitis (EoE) is a chronic disorder in children that requires continued assessment of disease activity, involving repeated sedation, endoscopy, and biopsy analysis. We investigated whether mucosal impedance measurements can be used to monitor disease activity in pediatric patients with EoE.

METHODS

We measured mucosal impedance at 3 locations in the esophagus in pediatric patients (1-18 years old; 32 with active EoE, 10 with inactive EoE, 32 with nonerosive reflux disease [NERD]) and 53 children with symptoms but normal findings from histologic analyses (controls) undergoing routine esophagogastroduodenoscopy at the Vanderbilt Pediatric Gastroenterology Clinic. Pathologists reviewed biopsies per routine protocol, determined eosinophilic density, and graded spongiosis on an ordinal visual scale. Mucosal impedance measurements were compared within patient groups. The primary outcome was correlation of mucosal impedance measurements with disease activity, based on severity of spongiosis and eosinophil counts.

RESULTS

Mucosal impedance measurements were significantly lower in patients with active EoE at 2, 5, and 10 cm above the squamo-columnar junction (median values of 1069, 1368, and 1707, respectively) compared to patients with inactive EoE (median values of 3663, 3657, and 4494, respectively), NERD (median values of 2754, 3243, and 4387), and controls (median values of 3091, 3760, and 4509) (P < 0.001 for all comparisons to patients with active EoE). We found inverse correlations between mucosal impedance measurements and eosinophil count (P < 0.001), and spongiosis severity (P < 0.001).

CONCLUSIONS

Mucosal impedance measurements may provide immediate information about mucosal inflammation in children. Patients with active EoE have significantly lower mucosal impedance values than patients with inactive EoE, NERD, or controls; mucosal impedance measurements correlate inversely with eosinophil counts and spongiosis severity. Mucosal impedance is a promising rapid and less-invasive method to monitor EoE activity in pediatric patients with EoE; it could reduce costs and risks of disease monitoring.

Eosinophilic Esophagitis Clinical Manifestations and Differential Diagnosis

As a chronic inflammatory disease with eosinophilic infiltrate of the esophagus, eosinophilic esophagitis (EoE) causes a variety of gastrointestinal (GI) clinical manifestations. None of the symptoms, endoscopic features, or biopsy findings is pathognomonic of the disease, even with high degrees of esophageal eosinophilia. The pathogenesis has been explored by several studies, yet it still far from being completely understood. Evidence supports a role of allergen-driven Th2 lymphocyte mechanism, though not in every patient. This article addresses the disease's clinical manifestations, endoscopic findings, diagnosis, and differential diagnoses. In addition to the current diagnostic criteria, we summarize some recently emerging procedures that promise of enhancing more precise diagnosis and institution of early appropriate management, with consequent better quality of life and reduction of complications.

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.

The role of endoscopy in eosinophilic esophagitis: from diagnosis to therapy

Eosinophilic esophagitis (EoE) has arisen as a common disorder in current clinical and endoscopic gastroenterology practice. Areas covered: A comprehensive review of the literature to summarize and update different aspects related with the use of endoscopy in the diagnostic workout and treatment of pediatric and adult EoE patients is conducted. Expert commentary: Endoscopic features in EoE are frequently subtle, so were inadverted in some initial reports of the disease. Literature has described a wide number of EoE-associated features, systematized in the EREFS classification, which standardized the grade and severity of exudates, rings, edema, furrows, and strictures. The insufficient reliability of these features to predict eosinophilic inflammation still makes biopsies essential in diagnosing or monitoring EoE. EoE causes half of the food impactions requiring endoscopy; food impaction leads to EoE diagnosis in up to half of cases. Long term consequences of EoE include esophageal remodeling leading to strictures and narrowing, thus impairing symptoms and needs dilation. Recognizing the risks from dilation in EoE required carrying out a safe technique to avoid the high complication rate reported in the early literature. Endoscopic dilation should be considered in patients with esophageal narrowing and dysphagia/food impaction unresponsive to diet or drugs-based anti-inflammatory treatment.

ALOX15 Immunohistochemistry Aids in the Diagnosis of Eosinophilic Esophagitis on Pauci-eosinophilic Biopsies in Children

Histologically, esophageal biopsies should have ≥15 intraepithelial eosinophils (IEEs) per high power field (HPF) to support a clinicopathologic diagnosis of eosinophilic esophagitis (EoE). Children with clinically apparent EoE may show pauci-eosinophilic biopsies due to patchy involvement. Immunostaining (Immunohistochemistry) for arachidonate-15 lipooxygenase (ALOX15) has been demonstrated to be a sensitive marker for EoE. We retrospectively assessed the expression of ALOX15 in 48 biopsies from 21 patients with established diagnosis of EoE and with tissue fragments below the threshold of 15 IEEs/HPF. Fragments were classified into pauci-eosinophilic and non-pauci-eosinophilic groups using cutoffs of 10 and 15 IEEs/HPF. Controls included patients with reflux and normal biopsies. Sixty-five (43.9%) fragments showed <10 IEEs/HPF and 83 (56.1%) showed ≥10 IEEs/HPF. Using a cutoff of 15 IEEs/HPF, 87 (58.7%) fragments showed <15 IEEs/HPF while 61 fragments (41.2%) had ≥15 IEEs/HPF. ALOX15 was positive in 53/65 (81.5%) of fragments with <10 IEEs/HPF versus 82/83 (98.8%) of fragments with ≥10 IEEs/HPF ( P < .001). For a cutoff of 15 IEEs/HPF, 75/87 (86.2%) of pauci-eosinophilic fragments were ALOX15-positive, while 60/61(98.4%) of biopsies meeting the threshold were positive ( P < .001). In 3/21 (14.3%) patients with EoE, all of the fragments (n = 7) were pauci-eosinophilic and all of them were positive for ALOX15. Two of 24 patients with reflux (one with 9 and one with 14 IEEs/HPF) were also positive. Fragments from normal controls (0 IEEs/HPF) were negative. Our results support the utility of ALOX15 immunohistochemistry in supporting the diagnosis of EoE in rare situations with strong clinical suspicion where no fragments reach 15 IEEs/HPF.

Eosinophilic esophagitis: published evidences for disease subtypes, indications for patient subpopulations, and how to translate patient observations to murine experimental models

Eosinophilic esophagitis (EoE) is a chronic inflammatory disorder of the esophagus and commonly classified as a Th2-type allergy. Major advances in our understanding of the EoE pathophysiology have recently been made, but clinicians struggle with highly unpredictable therapy responses indicative of phenotypic diversity within the patient population. Here, we summarize evidences for the existence of EoE subpopulations based on diverse inflammatory characteristics of the esophageal tissue in EoE. Additionally, clinical characteristics of EoE patients support the concept of disease subtypes. We conclude that clinical and experimental evidences indicate that EoE is an umbrella term for conditions that are unified by esophageal eosinophilia but that several disease subgroups with various inflammatory esophageal patterns and/or different clinical features exist. We further discuss strategies to study the pathophysiologic differences as observed in EoE patients in murine experimental EoE. Going forward, models of EoE that faithfully mimic EoE subentities as defined in humans will be essential because mechanistic studies on triggers which regulate the onset of diverse EoE subpopulations are not feasible in patients. Understanding how and why different EoE phenotypes develop will be a first and fundamental step to establish strategies that integrate individual variations of the EoE pathology into personalized therapy.