The oesophageal string test: a novel, minimally invasive method measures mucosal inflammation in eosinophilic oesophagitis

A pilot study of omalizumab in eosinophilic esophagitis

Eosinophilic disorders of the gastrointestinal tract are an emerging subset of immune pathologies within the spectrum of allergic inflammation. Eosinophilic Esophagitis (EoE), once considered a rare disease, is increasing in incidence, with a rate of over 1 in 10,000 in the US, for unknown reasons. The clinical management of EoE is challenging, thus there is an urgent need for understanding the etiology and pathophysiology of this eosinophilic disease to develop better therapeutic approaches. In this open label, single arm, unblinded study, we evaluated the effects of an anti-IgE treatment, omalizumab, on local inflammation in the esophagus and clinical correlates in patients with EoE. Omalizumab was administered for 12 weeks to 15 subjects with long standing EoE. There were no serious side effects from the treatment. Esophageal tissue inflammation was assessed both before and after therapy. After 3 months on omalizumab, although tissue Immunoglobulin E (IgE) levels were significantly reduced in all but two of the subjects, we found that full remission of EoE, which is defined as histologic and clinical improvement only in 33% of the patients. The decrease in tryptase-positive cells and eosinophils correlated significantly with the clinical outcome as measured by improvement in endoscopy and symptom scores, respectively. Omalizumab-induced remission of EoE was limited to subjects with low peripheral blood absolute eosinophil counts. These findings demonstrate that in a subset of EoE patients, IgE plays a role in the pathophysiology of the disease and that anti-IgE therapy with omalizumab may result in disease remission. Since this study is open label there is the potential for bias, hence the need for a larger double blind placebo controlled study. The data presented in this pilot study provides a foundation for proper patient selection to maximize clinical efficacy.

Non-invasive ultrasound to identify eosinophil granule proteins in eosinophilic esophagitis

Although traditional microbubble contrast agents are bright, the high contrast of gas bubbles and air-water interfaces in the upper gastrointestinal tract renders these agents less useful for diagnosing diseases such as eosinophilic esophagitis, a disease characterized by patchy infiltration of eosinophils into the esophagus. Here we report a first-in-class ultrasound contrast enhancement agent composed of echogenic insulin particles, which are labeled with molecular recognition elements to diagnose eosinophil-associated diseases. We prepared solid echogenic insulin particles, tethered antibodies to eosinophil granule major basic protein 1 (MBP-1) to their surfaces and experimentally evaluated binding of these agents to MBP-1 on ex vivo non-human primate esophagi. We found that insulin particles can be readily observed by ultrasound and bind to MBP-1-coated esophagi within minutes. Our results suggest the potential of this new class of solid contrast agents to image, diagnose and improve management of eosinophilic esophagitis.

How do gastroenterologists assess overall activity of eosinophilic esophagitis in adult patients?

OBJECTIVES

There is no "gold standard" for assessing disease activity in patients with eosinophilic esophagitis (EoE). We aimed to compare physicians' judgment of EoE activity with patients' judgment of symptom severity. We also aimed to examine the relative contribution of symptoms as well as endoscopic and histologic findings in shaping physicians' judgment of EoE activity.

METHODS

Six gastroenterologists (all EoE experts) assessed EoE-associated symptoms in adult patients. Patients completed a symptom instrument and provided global assessment of EoE symptom severity (PatGA) (Likert scale: 0 (inactive) to 10 (most active)). Following esophagogastroduodenoscopy with biopsy sampling, gastroenterologists provided a global assessment of EoE activity (PhysGA) (Likert scale from 0 to 10) based on patient history and endoscopic and histologic findings. Linear regression and analysis of variance was used to quantify the extent to which variations in severity of EoE symptoms and endoscopic and histologic findings explain variations in PhysGA.

RESULTS

A total of 149 EoE patients were prospectively included (71.8% male, median age at inclusion 38 years, 71.8% with concomitant allergies). A moderate positive correlation between PhysGA and PatGA (rho=0.442, P<0.001) was observed and the mean difference in the Bland-Altman plot was 1.77. Variations in severity of endoscopic findings, symptoms, and histologic findings alone explained 53%, 49%, and 30%, of the variability in PhysGA, respectively. Together, these findings explained 75% of variability in PhysGA.

CONCLUSIONS

Gastroenterologists rate EoE activity mainly on the basis of endoscopic findings and symptoms and, to a lesser extent, on histologic findings.

Translating new developments in eosinophilic esophagitis pathogenesis into clinical practice

OPINION STATEMENT

New developments in eosinophilic esophagitis (EoE) pathogenesis are shaping our current therapeutic and management strategies. EoE is a chronic allergic inflammatory disease with progression to fibrostenotic disease. The disease warrants early diagnosis and long-term maintenance therapy. The diagnosis of EoE should be based on the concept of an allergy-mediated disease with esophageal dysfunction and esophageal eosinophilia. Recent findings suggest that proton pump inhibitor (PPI)-responsive esophageal eosinophilia (PPI-REE) is likely a continuum of EoE or a similar T-helper 2 (Th2)-mediated allergic process. PPIs have therapeutic properties that can benefit both gastroesophageal reflux disease (GERD) and EoE. Therefore, PPIs should be considered not a diagnostic tool but, rather, a therapeutic option for EoE. If patients are PPI nonresponsive, then dietary therapy or steroid therapy should be considered. Dilation can be reserved as adjuvant therapy for severe fibrostenotic lesions.

Recent advances in the pathological understanding of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic allergen-mediated inflammatory disease of the esophagus. This inflammation leads to feeding difficulties, failure to thrive and vomiting in young children, and causes food impaction and esophageal stricture in adolescents and adults. In the 20 years since EoE was first described, we have gained a great deal of knowledge regarding the genetic predisposition of disease, the inflammatory milieu associated with EoE and the long-term complications of chronic inflammation. Herein, we summarize the important breakthroughs in the field including both in vitro and in vivo analysis. We discuss insights that we have gained from large-scale unbiased genetic analysis, a multitude of genetically and chemically altered mouse models of EoE and most importantly, the results of clinical trials of various pharmacologic agents. Understanding these successes and failures may be the key to developing more effective therapeutic strategies.

Accuracy, safety, and tolerability of tissue collection by Cytosponge vs endoscopy for evaluation of eosinophilic esophagitis

BACKGROUND & AIMS

Management of eosinophilic esophagitis (EoE) requires repeated endoscopic collection of mucosal samples to assess disease activity and response to therapy. An easier and less expensive means of monitoring of EoE is required. We compared the accuracy, safety, and tolerability of sample collection via Cytosponge (an ingestible gelatin capsule comprising compressed mesh attached to a string) with those of endoscopy for assessment of EoE.

METHODS

Esophageal tissues were collected from 20 patients with EoE (all with dysphagia, 15 with stricture, 13 with active EoE) via Cytosponge and then by endoscopy. Number of eosinophils/high-power field and levels of eosinophil-derived neurotoxin were determined; hematoxylin-eosin staining was performed. We compared the adequacy, diagnostic accuracy, safety, and patient preference for sample collection via Cytosponge vs endoscopy procedures.

RESULTS

All 20 samples collected by Cytosponge were adequate for analysis. By using a cutoff value of 15 eosinophils/high power field, analysis of samples collected by Cytosponge identified 11 of the 13 individuals with active EoE (83%); additional features such as abscesses were also identified. Numbers of eosinophils in samples collected by Cytosponge correlated with those in samples collected by endoscopy (r = 0.50, P = .025). Analysis of tissues collected by Cytosponge identified 4 of the 7 patients without active EoE (57% specificity), as well as 3 cases of active EoE not identified by analysis of endoscopy samples. Including information on level of eosinophil-derived neurotoxin did not increase the accuracy of diagnosis. No complications occurred during the Cytosponge procedure, which was preferred by all patients, compared with endoscopy.

CONCLUSIONS

In a feasibility study, the Cytosponge is a safe and well-tolerated method for collecting near mucosal specimens. Analysis of numbers of eosinophils/high-power field identified patients with active EoE with 83% sensitivity. Larger studies are needed to establish the efficacy and safety of this method of esophageal tissue collection. ClinicalTrials.gov number: NCT01585103.

Accuracy of liquid cytology in the diagnosis and monitoring of eosinophilic oesophagitis

BACKGROUND

Oesophagoscopy with biopsy is considered the gold standard for diagnosing and monitoring eosinophilic oesophagitis (EoE). Therefore is important to discover less-invasive diagnostic methods.

METHODS

Cytology specimens were obtained in patients with active EoE (AEoE) (≥15 eos/hpf) and EoE in remission (EoER) (<15 eos/hpf). The samples were assessed by two independent pathologists and were compared with biopsy samples. EoE cytology specimens were compared with specimens obtained from patients with GERD.

RESULTS

Specimens of 36 patients (69.4% male, mean age 30.88 years) were included. AEoE (17, 47.2%), EoER (11, 30.5%) and GERD (22.2%). eos/hpf in cytology (AEoE 9.23 vs. EoER 1.54 vs. GERD 2, p = 0.01). Linear correlation between eos/hpf average biopsy and cytology eos/hpf: r = 0.57, p < 0.001. For diagnosis of EoE ≥3 eos/hpf in cytology obtained a sensitivity of 70%, specificity 81%, PPV 86% and NPV 60% (AUC = 0.81, p = 0.01). For detection of AEoE, ≥3 eos/hpf in LBC obtained a sensitivity of 70%, specificity 82%, PPV 81% and NPV 66% (AUC = 0.87, p = 0.001).

CONCLUSIONS

LBC in oesophageal aspirate seems to be effective for the diagnosis and monitoring activity in EoE. These results support the usefulness of non-invasive methods for the diagnosis and monitoring of EoE.

Advances in clinical management of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic immune/antigen-mediated clinicopathologic condition that has become an increasingly important cause of upper gastrointestinal morbidity in adults and children over the past 2 decades. It is diagnosed based on symptoms of esophageal dysfunction, the presence of at least 15 eosinophils/high-power field in esophageal biopsy specimens, and exclusion of competing causes of esophageal eosinophilia, including proton pump inhibitor-responsive esophageal eosinophilia. We review what we have recently learned about the clinical aspects of EoE, discussing the clinical, endoscopic, and histological features of EoE in adults and children. We explain the current diagnostic criteria and challenges to diagnosis, including the role of gastroesophageal reflux disease and proton pump inhibitor-responsive esophageal eosinophilia. It is also important to consider the epidemiology of EoE (with a current incidence of 1 new case per 10,000 per year and prevalence of 0.5 to 1 case per 1000 per year) and disease progression. We review the main treatment approaches and new treatment options; EoE can be treated with topical corticosteroids, such as fluticasone and budesonide, or dietary strategies, such as amino acid-based formulas, allergy test-directed elimination diets, and nondirected empiric elimination diets. Endoscopic dilation has also become an important tool for treatment of fibrostenotic complications of EoE. There are a number of unresolved issues in EoE, including phenotypes, optimal treatment end points, the role of maintenance therapy, and treatment of refractory EoE. The care of patients with EoE and the study of the disease span many disciplines; EoE is ideally managed by a multidisciplinary team of gastroenterologists, allergists, pathologists, and dieticians.

Eosinophilic esophagitis: an emerging disease in childhood - review of diagnostic and management strategies

Eosinophilic esophagitis is a chronic immune/antigen mediated inflammatory disease of the esophagus. It comprises a separate entity of increasing incidence and prevalence in children and adults. The disease is characterized by histological evidence of dense esophageal tissue eosinophilia in the presence of a variety of upper GI symptoms including vomiting, dysphagia, food impaction, and odynophagia. Cornerstone of treatment is dietary intervention and/or the off-label use of swallowed topical corticosteroids. New drug therapies are under investigation. In this review, we focus on the diagnostic approach and the currently available treatment strategies.

Eosinophilic esophagitis: a practical approach to diagnosis and management

Eosinophilic esophagitis (EoE) has emerged as a common cause of dysphagia and food impaction in children and adults. A trial of proton pump inhibitor (PPI) therapy is a mandatory diagnostic first step, given that at least one third of patients with suspected EoE will have PPI-responsive esophageal eosinophilia. Once EoE is diagnosed, short-and long-term therapeutic decision making may rely on patient symptoms, phenotype (inflammatory vs fibrostenotic) and preferences. Currently, the most reliable therapeutic targets are mucosal healing and caliber abnormalities resolution. Topical steroids followed by endoscopic dilation are recommended in symptomatic narrow caliber esophagus/strictures, whereas either topical steroids or dietary therapy are good short-term options for mucosal inflammation. Maintenance anti-inflammatory therapy is necessary to prevent esophageal fibrotic remodeling and stricture formation.

Twin and family studies reveal strong environmental and weaker genetic cues explaining heritability of eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic antigen-driven allergic inflammatory disease, likely involving the interplay of genetic and environmental factors, yet their respective contributions to heritability are unknown.

OBJECTIVE

To quantify the risk associated with genes and environment on familial clustering of EoE.

METHODS

Family history was obtained from a hospital-based cohort of 914 EoE probands (n = 2192 first-degree "Nuclear-Family" relatives) and an international registry of monozygotic and dizygotic twins/triplets (n = 63 EoE "Twins" probands). Frequencies, recurrence risk ratios (RRRs), heritability, and twin concordance were estimated. Environmental exposures were preliminarily examined.

RESULTS

Analysis of the Nuclear-Family-based cohort revealed that the rate of EoE, in first-degree relatives of a proband, was 1.8% (unadjusted) and 2.3% (sex-adjusted). RRRs ranged from 10 to 64, depending on the family relationship, and were higher in brothers (64.0; P = .04), fathers (42.9; P = .004), and males (50.7; P < .001) than in sisters, mothers, and females, respectively. The risk of EoE for other siblings was 2.4%. In the Nuclear-Family cohort, combined gene and common environment heritability was 72.0% ± 2.7% (P < .001). In the Twins cohort, genetic heritability was 14.5% ± 4.0% (P < .001), and common family environment contributed 81.0% ± 4% (P < .001) to phenotypic variance. Probandwise concordance in monozygotic co-twins was 57.9% ± 9.5% compared with 36.4% ± 9.3% in dizygotic co-twins (P = .11). Greater birth weight difference between twins (P = .01), breast-feeding (P = .15), and fall birth season (P = .02) were associated with twin discordance in disease status.

CONCLUSIONS

EoE RRRs are increased 10- to 64-fold compared with the general population. EoE in relatives is 1.8% to 2.4%, depending on relationship and sex. Nuclear-Family heritability appeared to be high (72.0%). However, the Twins cohort analysis revealed a powerful role for common environment (81.0%) compared with additive genetic heritability (14.5%).

Cellular and molecular immunological mechanisms in eosinophilic esophagitis: an updated overview of their clinical implications

Eosinophilic esophagitis (EoE) is a pathophysiologically complex disorder driven by distinct, multiple mechanisms involving a large number of cells, molecules, and genes. Associated with food allergy from its initial descriptions, a key role for the Th2-type cytokines IL-5 and IL-13 in recruiting and activating eosinophils has been described. Epithelial cells have been recognized as major effectors in initiating EoE, both through their recruitment of iNKT cells towards the esophageal epithelium, which constitutes a major cytokine source, and through the release of eotaxin-3 and other chemoattractants. Epithelial and mesenchymal-released TSLP is a key regulator for which a connecting role between the adaptive and innate mucosal-associated immune response has been suggested. Finally, activated eosinophil- and mast cell-derived TGF β1 secretion is crucial in EoE-associated tissue remodeling.

Update on basic and clinical aspects of eosinophilic oesophagitis

The identification of a distinct syndrome, designated eosinophilic oesophagitis (EoE), with its own clinical and histopathological characteristics, was first described in the early 1990s. Meanwhile intense research has uncovered many molecular, immunological and clinical aspects of this chronic-inflammatory disorder. This article focuses exclusively on basic and clinical insights of EoE gathered during the last few years. Regarding aetiopathogenesis it has become clear that EoE is a food-triggered disease with milk and wheat as the dominant culprit food categories. However, it is still debated whether a disturbed mucosal integrity allowing allergens to cross the mucosal barrier, or changes in wheat and milk manufacturing might induce these inflammatory responses. Furthermore, basic science and clinical studies have accordingly confirmed that a chronic eosinophilic inflammation leads to a remodelling of the oesophagus with micro- and macro-morphological alterations, ending in a strictured oesophagus with impaired function. Fortunately, long-term therapeutic trials, using either topical corticosteroids or dietary allergen avoidance, have demonstrated that this sequela can be prevented or even reversed. This finding is of clinical relevance as it supports the initiation of a consistent anti-inflammatory therapy. Nevertheless, EoE is still an enigmatic disease and the long list of unanswered questions will certainly stimulate further research.

Steroids versus dietary therapy for the treatment of eosinophilic esophagitis

PURPOSE OF REVIEW

Eosinophilic esophagitis (EoE) is a condition characterized by dense mucosal eosinophilia in conjunction with symptoms of esophageal dysfunction. Since both the incidence and prevalence of EoE are on the rise in both children and adults, understanding the various treatment options available is imperative in choosing the proper treatment for each patient. This article will highlight the major strides in both medical and dietary treatment of EoE in the past year.

RECENT FINDINGS

Whereas prior studies have shown that medical therapy with topical corticosteroids is effective in treating EoE, this more recent literature highlights some of the limitations of this approach, raising awareness that development of better drug delivery models is greatly needed. The review also describes the recent advances in the field of dietary therapy for this disease, particularly in adults, and further supports the notion that the pathophysiology of this disease in children and adults is similar, with food antigens driving this disease.

SUMMARY

Both medical and dietary therapy are effective for treating adults and children with EoE. Choosing the optimal treatment approach should be individualized based both on patient goals and on available local resources. Future prospective clinical trials comparing these two treatment modalities are needed to help understand comparable effectiveness as well as to help understand potential predictors of response to treatment and identify optimal therapeutic endpoints.

Eosinophilic esophagitis and proton pump inhibitors: controversies and implications for clinical practice

Eosinophilic esophagitis (EoE) is a major cause of dysphagia and food impaction. Recognition and diagnosis of EoE have been increasing rapidly, but the role of proton pump inhibitors (PPIs) for the diagnosis of EoE and treatment of esophageal eosinophilia remains controversial. Initial diagnostic algorithms for EoE relied on a PPI trial to distinguish EoE from gastroesopha-geal reflux disease, a common cause of esophageal eosinophilia. This approach has become complicated by the recent recognition of PPI-responsive esophageal eosinophilia (PPI-REE), a disorder characterized by clinicopathologic features similar to EoE but that resolve with high-dose PPI therapy. The mechanism of PPI action for treatment of esophageal eosinophilia may rely not only on acid suppression but also on novel anti-inflammatory effects of the PPIs themselves. Treatment with PPI therapy is now considered a required step before a formal diagnosis of EoE can be made, and continuing PPI therapy in patients with PPI-REE is a common strategy. However, the role of continuing PPI monotherapy in patients with EoE remains a matter of debate. The decision to do so should hinge on improvement in symptoms and histology as well as the need for ongoing dilation.

Development of a suspension array assay in multiplex for the simultaneous measurement of serum levels of four eosinophil granule proteins

The concentrations of major basic protein (MBP), eosinophil cationic protein (ECP), eosinophil derived neurotoxin (EDN) and eosinophil peroxidase (EPO) have been associated with eosinophilic disease severity. Whereas a variety of techniques have been used to measure individual eosinophil granule protein concentration, none of these methods efficiently measures MBP, ECP, EDN and EPO simultaneously. A multiplex suspension array system was developed to simultaneously measure the concentrations of MBP, ECP, EDN and EPO in serum. The assay showed excellent inter- and intra-assay reliability, and serum levels of MBP, ECP and EDN from eosinophilic subjects analyzed by ELISA and multiplex were highly correlated (r=0.8579; P<0.0001, r=0.6356; P=0.0006 and r=0.8600; P<0.0001, respectively, Spearman rank correlation). Moreover, the multiplex assay required 500-fold less serum than a single ELISA to achieve comparable sensitivity. Absolute eosinophil count and eosinophil surface expression of the activation marker, CD69, were significantly correlated with concentrations of MBP, EDN and EPO, but not ECP, in serum from eosinophilic subjects. Furthermore, subjects with eosinophilic gastrointestinal disorder and normal peripheral absolute eosinophil counts (<0.5×10(9)/l) had significantly increased concentrations of MBP (P<0.0001), ECP (P<0.0001), EDN (P=0.0001) and EPO (P<0.0001) compared to normal donors. In summary, the eosinophil granule protein multiplex assay provides a rapid and reliable way to measure eosinophil granule protein levels and should prove useful in assessing patterns of degranulation in patients with eosinophilic disorders.

Eosinophilic esophagitis: overview of clinical management

A validated disease-specific symptom-assessment tool for eosinophilic esophagitis (EoE) has yet to be approved by regulatory authorities for use in clinical trials. Relevant end points for daily practice include EoE-related symptoms and esophageal eosinophilic inflammation. Endoscopic features should also be taken into account when establishing a therapy plan. A reasonable clinical goal is to achieve a reduction in EoE-related symptoms and esophageal eosinophilic inflammation. Evidence is increasing to support an anti-inflammatory maintenance therapy, as this can reduce esophageal remodeling. In EoE patients in clinical remission, annual disease monitoring with symptom, endoscopic, and histologic assessments of sustained treatment response is recommended.

Eosinophilic esophagitis: historical perspective on an evolving disease

Initial case series describing children and adults with symptoms related to esophageal dysfunction and dense esophageal eosinophilia lead to recognition of a "new" disease, eosinophilic esophagitis (EoE). Clinical, basic, and translational studies have provided a deeper understanding of this somewhat enigmatic disease that mechanistically is defined as an antigen-driven condition limited to the esophagus. This article summarizes many of the key historical features of EoE and provides a glimpse of potential future developments.

Allergic mechanisms in eosinophilic esophagitis

Eosinophilic esophagitis is rapidly increasing in incidence. It is associated with food antigen-triggered, eosinophil-predominant inflammation, and the pathogenic mechanisms have many similarities to other chronic atopic diseases. Studies in animal models and from patients have suggested that allergic sensitization leads to food-specific IgE and T-helper lymphocyte type 2 cells, both of which seem to contribute to the pathogenesis along with basophils, mast cells, and antigen-presenting cells. In this review our current understandings of the allergic mechanisms that drive eosinophilic esophagitis are outlined, drawing from clinical and translational studies in humans as well as experimental animal models.

Eosinophilic esophagitis: emerging therapies and future perspectives

Twenty years have passed since eosinophilic esophagitis was first recognized as a new and distinct entity. Current treatment modalities for eosinophilic esophagitis include the "3 Ds": drugs, allergen avoidance with diet, and esophageal dilation. Drugs entail the limitation that only corticosteroids have a proven efficacy; most other compounds evoke only a minimal effect. Diets must be maintained continuously and they interfere markedly with the quality of life, possibly even involving some risk of malnutrition. A greater understanding of the immunopathogenesis, natural history, and disease spectrum will inevitably lead to improved therapeutic outcomes for this emerging entity.

Efficacy of dietary interventions for inducing histologic remission in patients with eosinophilic esophagitis: a systematic review and meta-analysis

BACKGROUND & AIMS

Various dietary interventions have been used to treat patients with eosinophilic esophagitis (EoE), yielding varied results. This systematic review assesses the efficacy of different dietary therapies in inducing disease remission.

METHODS

We performed a systematic search of the MEDLINE, EMBASE, and SCOPUS databases for studies investigating the efficacy of dietary interventions (reducing infiltration by immune cells <15 eosinophils/high-power field in esophageal biopsies) for pediatric and adult patients with EoE. Summary estimates, including 95% confidence intervals (CI), were calculated for exclusive feeding with amino acid-based elemental formulas, allergy test result-directed food elimination diets, and 6-food elimination diets (SFED). A fixed- or random-effects model was used depending on heterogeneity (I(2)); publication bias risks were assessed by means of funnel plot analysis.

RESULTS

The search yielded 581 references; of these, 33 were included in the quantitative summary. We analyzed data on a total of 1317 patients with EoE (1128 children and 189 adults) who received different dietary treatments. Elemental diets were effective for 90.8% of cases (95% CI, 84.7%-95.5%; I(2) = 52.3%), SFED for 72.1% (95% CI, 65.8%-78.1%; I(2) = 0), and allergy test result-directed food elimination for 45.5% of cases (95% CI, 35.4%-55.7%; I(2) = 75.1%). Additional strategies (elimination of cow's milk, gluten-free diets, and 4-food elimination diet) were also evaluated. Adults vs children had no significant differences in remission after dietary interventions (67.2% vs 63.3%).

CONCLUSIONS

Dietary interventions are effective in producing histologic remission in patients with EoE. Elemental diets and SFEDs were the most effective, achieving <15 eosinophils/high-power field in 90.8% and 72.1% of patients, respectively.

Eosinophil granule proteins: form and function

Experimental and clinical data strongly support a role for the eosinophil in the pathogenesis of asthma, allergic and parasitic diseases, and hypereosinophilic syndromes, in addition to more recently identified immunomodulatory roles in shaping innate host defense, adaptive immunity, tissue repair/remodeling, and maintenance of normal tissue homeostasis. A seminal finding was the dependence of allergic airway inflammation on eosinophil-induced recruitment of Th2-polarized effector T-cells to the lung, providing a missing link between these innate immune effectors (eosinophils) and adaptive T-cell responses. Eosinophils come equipped with preformed enzymatic and nonenzymatic cationic proteins, stored in and selectively secreted from their large secondary (specific) granules. These proteins contribute to the functions of the eosinophil in airway inflammation, tissue damage, and remodeling in the asthmatic diathesis. Studies using eosinophil-deficient mouse models, including eosinophil-derived granule protein double knock-out mice (major basic protein-1/eosinophil peroxidase dual gene deletion) show that eosinophils are required for all major hallmarks of asthma pathophysiology: airway epithelial damage and hyperreactivity, and airway remodeling including smooth muscle hyperplasia and subepithelial fibrosis. Here we review key molecular aspects of these eosinophil-derived granule proteins in terms of structure-function relationships to advance understanding of their roles in eosinophil cell biology, molecular biology, and immunobiology in health and disease.

Changing roles of eosinophils in health and disease

OBJECTIVE

To review and highlight the unappreciated roles of eosinophils suggested by recent studies.

DATA SOURCES

The literature, unpublished observations, and insights by the authors.

STUDY SELECTIONS

Basic studies of mouse models and patient-based clinical studies of disease.

RESULTS

Eosinophils are often thought of as destructive end-stage effector cells primarily linked to parasite host defense and dysregulated immune responses associated with allergic diseases, such as asthma. However, recent studies (ie, research focused on mechanisms of action and translational studies examining disease/inflammatory pathways) are suggesting far more complex roles for eosinophils. The goal of this review is 3-fold. (1) The authors examine the dynamic history of eosinophils and how physicians over time used this information to formulate defining hypotheses. Particular emphasis is placed on recent studies challenging the parochial view of host defense in favor of roles maintaining homeostasis through immune modulation and tissue remodeling/repair. (2) They discuss diagnostic approaches to assess eosinophils in clinical settings as a means of disease identification and subsequently as a measurement of disease severity. (3) They examine how contemporary views of eosinophils and their perceived roles in diseases have led to specific therapeutic strategies. The emphasis is to review the successes and failures of these strategies as the basis of formulating future clinical studies targeting eosinophils as potential therapies of disease.

CONCLUSION

Despite the complexities of eosinophil-mediated activities and the less than overwhelming success of initial attempts targeting these cells, eosinophils remain a potentially important focal target of disease diagnosis and subsequent treatment strategies.

Activity assessment of eosinophilic esophagitis

The activity of eosinophilic esophagitis (EoE) can be assessed with patient-reported outcomes and biologic measures. Patient-reported outcomes include symptoms and quality of life, whereas biologic measures refer to endoscopic, histologic, and biochemical activity (e.g. blood biomarkers). So far, a validated tool to assess EoE activity in the above-mentioned dimensions is lacking. Given the lack of a standardized way to assess EoE activity in the various dimensions, the results of different clinical trials may be difficult to compare. For symptom assessment in adult patients, the symptom 'dysphagia' should be evaluated according to different standardized food consistencies. Furthermore, symptom assessment should take into account the following items: avoidance of specific food categories, food modification, and time to eat a regular meal. A distinct symptom recall period (e.g. 2 weeks) has to be defined for symptom assessment. Performing an 'esophageal stress test' with ingestion of a standardized meal to measure symptom severity bears the potential risk of acute food bolus impaction and should therefore be avoided. The description of endoscopic findings in EoE has meanwhile been standardized. Histologic evaluation of EoE activity should report either the size of the high-power field used or count the eosinophils per mm(2). There is a current lack of blood biomarkers demonstrating a good correlation with histologic activity in esophageal biopsies. The development and validation of an adult and pediatric EoE activity index is urgently needed not only for clinical trials and observational studies, but also for daily practice.

Unmet diagnostic needs in eosinophilic esophagitis

The description of eosinophilic esophagitis (EoE) from a clinical, endoscopic, histologic and mechanistic perspective has emerged at a rapid pace. Nevertheless, there are many key areas of diagnosis which remain problematic. The first area is trying to identify a gold standard for EoE, particularly in its differentiation from gastroesophageal reflux disease. As a result, many of the consensus guidelines advise expensive and cumbersome steps with endoscopy and empiric courses of medication that would not be needed should a completely accurate method for identifying EoE be developed. We also grapple with the lack of an accurate test short of endoscopy and biopsy to diagnose and monitor treatment response in EoE. This is particularly problematic in food elimination diets where patients may require up to ten endoscopies to determine precise food avoidance. Finally, it is imperative that we diagnose factors that predict severity and phenotype of the disease. This will yield far clearer guidance concerning the level and duration of therapy needed on EoE patients.

The eosinophil surface receptor epidermal growth factor-like module containing mucin-like hormone receptor 1 (EMR1): a novel therapeutic target for eosinophilic disorders

BACKGROUND

Although several novel agents are currently in clinical trials for eosinophilic disorders, none has demonstrated efficacy in reducing blood and tissue eosinophilia in all subjects. Additional approaches are clearly needed.

OBJECTIVE

We sought to explore the potential of the human eosinophil surface receptor epidermal growth factor-like module containing mucin-like hormone receptor 1 (EMR1) as a therapeutic target for eosinophilic disorders.

METHODS

EMR1 expression was assessed in blood and bone marrow specimens from eosinophilic and healthy subjects, cell lines, CD34(+) cells differentiated in vitro, and tissue biopsy specimens by using flow cytometry, quantitative PCR, and immunostaining. Eosinophil targeting by a novel, humanized, afucosylated anti-EMR1 IgG1 was evaluated in vitro by using a natural killer cell-mediated killing assay and in vivo in cynomolgus monkeys.

RESULTS

Analysis of blood and bone marrow cells from healthy and eosinophilic donors and in vitro-differentiated CD34(+) cells confirmed restriction of human EMR1 surface and mRNA expression to mature eosinophils. Tissue eosinophils also expressed EMR1. Although EMR1 was highly expressed on eosinophils from all subjects, surface expression was negatively correlated with absolute eosinophil counts (r = -0.46, P < .001), and soluble plasma levels correlated positively with absolute eosinophil counts (r = 0.69, P < .001), suggesting modulation of EMR1 in vivo. Nevertheless, afucosylated anti-EMR1 mAb dramatically enhanced natural killer cell-mediated killing of eosinophils from healthy and eosinophilic donors and induced a rapid and sustained depletion of eosinophils in monkeys.

CONCLUSION

EMR1 expression is restricted to mature blood and tissue eosinophils. Targeting of eosinophils with afucosylated anti-EMR1 antibody shows promise as a treatment for eosinophilic disorders.

Unmet therapeutic needs in eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a clinicopathologic disease of increasing prevalence in children and adults worldwide. EoE is defined by a robust, acid-resistant, often panesophageal eosinophilia. Disease complications include food impactions and strictures. While much has been learned since it was first described in the late 1970s, there are still a number of unmet clinical needs. This review provides an overview of these and addresses our current state of progress in meeting these challenges. The best diagnostic criteria, the least invasive mechanisms for procuring tissue, the best therapeutic intervention, and an understanding of how therapies affect EoE natural history remain to be systematically addressed. In addition, the classification of EoE subjects by phenotype, genotype, and/or endotype is required but dependent upon further large-scale systematic studies.

Non- and semi-invasive methods of monitoring eosinophilic esophagitis

BACKGROUND/AIMS

Monitoring inflammation associated with eosinophilic esophagitis (EoE) relies on the identification of biomarkers that provide an objective measure of disease activity. To date, this metric has been the number of eosinophils in the squamous epithelial tissue. The search for alternative biomarkers as well as alternative methods to capture them has been the topic of much research.

METHODS

Based on clinical experience and a review of the literature, the aim of this chapter is to identify potential EoE biomarkers and methods to assess them.

RESULTS

With respect to the biomarkers, a number of candidates have arisen, including peripheral blood eosinophils, eosinophil granule proteins, Th2-related cytokines and exhaled nitric oxide. Methods to assess these biomarkers have included peripheral blood, luminal lavages and breath collections.

CONCLUSIONS

Future research will identify the best clinical outcome measure for EoE. While mucosal eosinophilia currently serves as a well-defined metric of inflammation, newer research studies will continue to address whether this number correlates reliably with other patient-reported outcomes, endoscopic findings, molecular analyses or other yet to be defined biomarkers.

Management guidelines of eosinophilic esophagitis in childhood

OBJECTIVES

Eosinophilic esophagitis (EoE) represents a chronic, immune/antigen-mediated esophageal disease characterized clinically by symptoms related to esophageal dysfunction and histologically by eosinophil-predominant inflammation. With few exceptions, 15 eosinophils per high-power field (peak value) in ≥1 biopsy specimens are considered a minimum threshold for a diagnosis of EoE. The disease is restricted to the esophagus, and other causes of esophageal eosinophilia should be excluded, specifically proton pump inhibitor-responsive esophageal eosinophilia. This position paper aims at providing practical guidelines for the management of children and adolescents with EoE.

METHODS

Relevant literature from searches of PubMed, CINAHL, and recent guidelines was reviewed. In the absence of an evidence base, recommendations reflect the expert opinion of the authors. Final consensus was obtained during 3 face-to-face meetings of the Gastroenterology Committee and 1 teleconference.

RESULTS

The cornerstone of treatment is an elimination diet (targeted or empiric elimination diet, amino acid-based formula) and/or swallowed, topical corticosteroids. Systemic corticosteroids are reserved for severe symptoms requiring rapid relief or where other treatments have failed. Esophageal dilatation is an option in children with EoE who have esophageal stenosis unresponsive to drug therapy. Maintenance treatment may be required in case of frequent relapse, although an optimal regimen still needs to be determined.

CONCLUSIONS

EoE is a chronic, relapsing inflammatory disease with largely unquantified long-term consequences. Investigations and treatment are tailored to the individual and must not create more morbidity for the patient and family than the disease itself. Better maintenance treatment as well as biomarkers for assessing treatment response and predicting long-term complications is urgently needed.

Dietary therapies for eosinophilic esophagitis

Eosinophilic esophagitis (EoE) represents a prevalent chronic esophageal disorder. Since the condition was first described, its pathophysiology has been known to have an immune-allergic origin, but the high response rate to dietary therapies based on feeding patients exclusively with amino acid-based elemental formulas (with complete elimination of table foods) has clearly established EoE as a particular form of food allergy. Nevertheless, the management of EoE in clinical practice remains widely heterogeneous, with topical steroids being a therapeutic mainstay. However, a growing body of evidence points to dietary therapy as an effective treatment option for both children and adults with EoE, as this approach is capable of achieving a sustained symptomatic and histological response without resorting to drugs. This article reviews the available data on the major types of dietary therapy for EoE, including elemental formula diets, skin allergy testing-directed elimination diets and empirical elimination diets based on common food allergens.

Eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic immune-mediated condition whereby infiltration of eosinophils into the esophageal mucosa leads to symptoms of esophageal dysfunction. EoE is encountered in a substantial proportion of patients undergoing diagnostic upper endoscopy. This review discusses the clinical, endoscopic, and histologic features of EoE and presents the most recent guidelines for its diagnosis. Selected diagnostic dilemmas are described, including distinguishing EoE from gastroesophageal reflux disease and addressing the newly recognized clinical entity of proton-pump inhibitor-responsive esophageal eosinophilia. Also highlighted is evidence to support both pharmacologic and nonpharmacologic treatments, including topical corticosteroids, dietary elimination therapy, and endoscopic dilation.