Basophil infiltration in eosinophilic oesophagitis and proton pump inhibitor-responsive oesophageal eosinophilia

Investigating immune profile by CyTOF in patients with eosinophilic esophagitis after treatment with orodispersible budesonide

Eosinophilic esophagitis (EoE) is a chronic Th2-mediated inflammatory disease of the esophagus driven by dietary or inhalant allergens which if left untreated, leads to fibrosis and poor esophageal function. Although the inflammation in the esophagus is dominated by eosinophils, there are also elevated levels of T and B cells. Blood samples from ten patients with EoE before and after treatment with orodispersible budesonide and 10 healthy controls were compared using cytometry by time-of-flight. An antibody panel was designed that covers the major immunological cell populations with a particular focus on eosinophils. The data was analyzed with multivariate methods and cluster analysis. Correlation analysis was done between immune markers and endoscopic, histological, and symptomatologic assessments. Our analysis revealed that patients with EoE had lower levels of effector memory T cells after treatment with orodispersible budesonide to the same level as healthy subjects. In addition, more suppressive eosinophils were present in the circulation of EoE patients before treatment and more immature eosinophils were present after treatment. Furthermore, levels of galectin-10+ eosinophils correlated with histological findings in esophageal tissue from EoE patients. In all patients, the peak eosinophils were decreased after treatment with orodispersible budesonide. Intriguingly, 90% of the patients had remission in the histological assessment and 50% improved in the endoscopic assessment. This study reports a detailed immune profile in patients with EoE before and after treatment with orodispersible budesonide and it is a step toward finding blood-based immune parameters that could be useful to monitor response to treatment.

The protective effects of Helicobacter pylori: A comprehensive review

Previous reports have estimated that approximately half of the world’s population is infected with Helicobacter pylori, the most prevalent infectious agent responsible for gastrointestinal illnesses. Due to the life-threatening effects of H. pylori infections, numerous studies have focused on developing medical therapies for H. pylori infections, while the commensal relationship and positive impacts of this bacterium on overall human health have been largely overlooked. The inhibitory efficacy of H. pylori on the progression of several chronic inflammatory disorders and gastrointestinal diseases has recently raised concerns about whether this bacterium should be eradicated in affected individuals or maintained in an appropriate balance depending on the patient’s condition. This review investigates the beneficial effects of H. pylori in preventing various diseases and discusses the potential association of conditions such as inflammatory disorders with the absence of H. pylori.

Mast Cell Esophagitis: A Novel Entity in Patients with Unexplained Esophageal Symptoms

It is not known whether esophageal mast cells may be a cause of unexplained esophageal symptoms. We aimed to determine the prevalence of esophageal mastocytosis in patients without other underlying causes of symptoms and assess the relationship between symptoms and mast cells. In this retrospective study, we identified adults with esophageal symptoms, a normal endoscopy, normal esophageal biopsies, and no definitive diagnosis during clinical evaluation. We quantified mast cell density (mast cells/mm2) in archived esophageal biopsies using tryptase immunohistochemistry, and compared mast cell levels by clinical features and physiologic testing. In the 87 patients identified (mean age 37, 72% female, 63% white, 92% non-Hispanic), common symptoms were dysphagia (76%), heartburn (71%), and chest pain (25%). Overall, the mean esophageal epithelial mast cell count was 83.0 ± 51.8 mast cells/mm2; 60% of patients had ≥ 60 mast/mm2, and 17% had ≥ 120 masts/mm2. There were no differences in mast cell counts by type of esophageal testing. Mast cell levels did not differ significantly by type of symptoms, atopic status, medications, smoking status, or alcohol use. There were also no major differences in clinical characteristics by mast cell quartiles or thresholds. In conclusion, esophageal mast cell infiltration was common in patients with symptoms unexplained by prior testing, and levels were higher than previously published values for patients with no underlying esophageal condition. Mast cell esophagitis could be a novel cause of unexplained esophageal symptoms in a subset of patients, though it reamins to be determined if such patients benefit from mast cell-targeted treatment.

Expression of CD25, mast cell markers and T-cell markers in eosinophilic esophagitis

While eosinophilic esophagitis (EOE) is defined by histologic presence of eosinophils, a few studies have established the presence of mast cells in EOE and even shown their correlation with symptom persistence despite resolution of eosinophils. Expression of aberrant mast cell markers CD25 and CD2 have not been studied in EOE. This study quantifies the number of hotspot cells per high power field expressing CKIT/CD117, tryptase, CD25, CD2 and CD3 by immunohistochemical stains in endoscopic esophageal biopsies of the following three cohorts: (1) established and histologically confirmed EOE, (2) suspected EOE with biopsies negative for eosinophils, and (3) no history of or suspicion for EOE with histologically unremarkable biopsies. In this study, mast cells were highlighted by CKIT and tryptase in EOE, and not seen in other clinically mimicking cases. There were also significantly higher densities of CD25 and pan-T-cell marker staining in EOE cases. These findings suggest an inflammatory cellular milieu in EOE, beyond just eosinophils, that can be demonstrated by immunohistochemistry, and that invite further study into the role that these cells may play in EOE.

Examining the Role of Type 2 Inflammation in Eosinophilic Esophagitis

Eosinophilic esophagitis (EoE) is a chronic type 2 inflammatory disease characterized by an eosinophilic inflammatory infiltrate in the esophagus, leading to remodeling, stricture formation, and fibrosis. Triggered by food and aeroallergens, type 2 cytokines interleukin (IL)-4, IL-13, IL-5 produced by CD4+ T helper 2 cells (Th2), eosinophils, mast cells, basophils, and type 2 innate lymphoid cells alter the esophageal epithelial barrier and increase inflammatory cell tissue infiltration. Clustering analysis based on the expression of type 2 inflammatory genes demonstrated the diversity of EoE endotypes. Despite the availability of treatment options for patients with EoE, which include dietary restriction, proton pump inhibitors, swallowed topical steroids, and esophageal dilation, there are still no Food and Drug Administration-approved medications for this disease; as such, there are clear unmet medical needs for these patients. A number of novel biologic therapies currently in clinical trials represent a promising avenue for targeted therapeutic approaches in EoE. This review summarizes our current knowledge on the role of type 2 inflammatory cells and mediators in EoE disease pathogenesis, as well as the future treatment landscape targeting underlying inflammation in EoE.

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.

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.

An Update on Eosinophilic Esophagitis: Etiological Factors, Coexisting Diseases, and Complications

BACKGROUND

Eosinophilic esophagitis (EoE) is an immune-mediated clinicopathological condition characterized by esophageal infiltration with eosinophils resulting in chronic inflammation and stricture.

SUMMARY

The recent increase in the incidence of EoE and the characteristic presentation of symptoms with difficulty swallowing and food bolus impaction has raised key concerns of clinicians as well as researchers. EoE often presents with dysphagia, food impaction, nausea, regurgitation or vomiting, and decreased appetite. It is more common in males, affecting both adults and children. The causative manner of this condition is complex and multifactorial. Throughout recent years, researchers have made a significant contribution to understanding the pathogenesis of EoE, genetic background, natural history, work on allergy, and standardization in the evaluation of disease activity. There is relatively high prevalence of EoE among the population, emphasizing the importance of this disease. Key messages: Esophageal involvement with eosinophils may be manifested as isolated or with coexisting conditions and should be taken into consideration in the differential diagnosis. This study aimed to provide gastroenterologists with novel insights into the evaluation of esophageal involvement with eosinophils and to pay special attention to the etiological factors, coexisting clinical diseases, and complications.

Classification of patients with esophageal eosinophilia by patterns of sensitization revealed by a diagnostic assay for multiple allergen-specific IgEs

BACKGROUND

Eosinophilic esophagitis (EoE) is considered to be an immunoglobulin E (IgE)-mediated allergic disorder. Our goal was to examine IgE-mediated allergic sensitization patterns in patients with esophageal eosinophilia (EE).

METHODS

We enrolled subjects with EE who underwent evaluation with a diagnostic panel to document multiple allergen-specific IgEs. Statistically significant groups were identified by cluster analysis. We also defined allergens based on their characteristics including outdoor, indoor, plant, and animal allergens.

RESULTS

We classified patients with EE into 3 distinct groups, including cluster 1 (n = 62) who were minimally sensitized to most allergens except pollen and house dust, cluster 2 (n = 30) who were hypersensitized to outdoor and plant allergens, and cluster 3 (n = 15) who were hypersensitized to most allergens, most notably to indoor and animal allergens. Dysphagia reported among those in clusters 1, 2, and 3 at 35.5%, 46.7%, and 73.3%, respectively, (p = 0.028) and EoE endoscopic reference scores (EREFS) at 3.0, 6.0, and 8.0, respectively, (p < 0.001) differed significantly between the 3 clusters. Those in cluster 3 had a significantly higher prevalence of dysphagia (35.5% vs. 73.3%, p = 0.030), and higher EREFS with respect to rings (0.3 vs. 0.9, p = 0.003) and strictures (0.0 vs. 0.13, p = 0.011) compared to those in cluster 1.

CONCLUSIONS

IgE-mediated allergic sensitization patterns are associated with clinical features of patients with EE. Use of a diagnostic panel that detects multiple allergen-specific IgEs can help to explain the heterogeneous phenotype of this patient cohort.

Immunohistochemical expression of filaggrin is decreased in proton pump inhibitor non-responders compared with proton pump inhibitor responders of eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is an allergic gastrointestinal disease that features eosinophilic infiltration of esophageal mucosa, but the role of barrier dysfunction of the epithelium in its pathogenesis remains to be elucidated. Clinically, EoE is divided into proton pump inhibitor-non-responders (PPI-NR) and PPI-responders (PPI-R). Our main aims were to investigate the differences of expression of epidermal differential complex (EDC) proteins and desmoglein that are considered to play important roles in formation of the epidermal skin barrier between these two conditions and to seek the usefulness of the differences in pathological diagnosis. Conventional histopathological findings and allergic background were also compared.

METHODS

Twenty-nine PPI-NR and 44 PPI-R were recruited, and 35 reflux esophagitis patients were also enrolled. After clinical information and histopathological findings were reviewed, immunohistochemical expression of EDC proteins (filaggrin, loricrin, and involucrin) and desmoglein in all three groups were examined and semi-quantitatively scored.

RESULTS

Regarding allergic conditions, the prevalence of asthma was significantly higher in PPI-NR than in PPI-R. Other allergic conditions showed no differences. Histopathological findings did not exhibit the statistical difference between PPI-NR and PPI-R. However, immunostaining score of filaggrin in PPI-NR was significantly lower than in PPI-R, although the expressions of involucrin, loricrin and desmoglein demonstrated no differences.

CONCLUSIONS

The results suggest a role of reduced filaggrin expression in the difference of effectiveness of PPI treatment between PPI-NR and PPI-R. Moreover, immunohistochemical determination of filaggrin expression in EoE patients could be informative in the clinical decision of how to treat the patients.

Patient-Reported Outcomes and Blood-Based Parameters Identify Response to Treatment in Eosinophilic Esophagitis

BACKGROUND

Noninvasive methods to assess treatment response in eosinophilic esophagitis are needed.

AIMS

Our aim was to determine whether a blood-based biomarker panel centered on immune parameters could identify histologic response to treatment in eosinophilic esophagitis patients.

METHODS

A pilot study involving adult patients with active eosinophilic esophagitis recruited at two Ear, Nose, Throat clinics in Sweden was designed. The patients (n = 20) donated blood and esophageal biopsies and filled in three questionnaires before and after a 2-month course of topical corticosteroids. Blood samples were analyzed for absolute levels of granulocytes and T cells and the fractions of eosinophils expressing 10 different surface markers by flow cytometry. All data were analyzed by multivariate methods of pattern recognition.

RESULTS

Multivariate modeling revealed that a combination of 13 immune parameters and 10 patient-reported outcome scores were required to create a model capable of separating responders (n = 15) from non-responders (n = 5). Questions regarding symptoms of esophageal dysfunction and capacity to eat certain foods from two of the questionnaires were discriminatory in the multivariate model, as were absolute counts of T cells, eosinophils, and eosinophil expression of activation markers and cell adhesion molecules.

CONCLUSIONS

A combination of blood-based immune parameters and directed questions may prove helpful to monitor response to treatment, perhaps reducing the need for repeat endoscopies in eosinophilic esophagitis patients in the future.

Symptom-based diagnostic approach for eosinophilic esophagitis

The prevalence of eosinophilic esophagitis (EoE) has been increasing in Japan. Although the diagnosis of EoE is based on simple criteria that include the presence of esophageal symptoms and esophageal eosinophilia on biopsies, there are several important issues associated with the diagnostic approach. Following an extensive literature search, the symptoms of 886 EoE cases in Japanese adults were analyzed and divided into three categories as follows: (1) typical symptoms, such as dysphagia (53%); (2) other upper GI symptoms (40%); and (3) no symptoms found during screening or medical examination, i.e., "asymptomatic esophageal eosinophilia" (19%). The diagnostic approach was reviewed according to these categories as well as according to the presence or absence of esophageal eosinophilia. The present manuscript describes the current therapeutic strategy of EoE and ultimately proposes a symptom-based diagnostic approach for EoE.

Reconsidering the "protective" hypothesis of Helicobacter pylori infection in eosinophilic esophagitis

Since its discovery, Helicobacter pylori (H. pylori) has attracted attention in the biomedical world with its numerous pathophysiologic implications, both gastrointestinal and systemic. Beyond its well-established carcinogenic properties, emerging evidence also supports "harmful" proinflammatory and neurodegenerative roles of H. pylori. On the other hand, H. pylori infection has been proposed to be "protective" against several diseases, such as asthma and gastroesophageal reflux disease. Eosinophilic esophagitis (EoE) is a relatively new, allergen/immune-mediated disease, which has also been linked to these considerations. Main arguments are a postulated shift of immune responses by H. pylori from T helper 2 (T_H 2) to T_H 1 polarization, as well as a potential decline of the H. pylori burden with the dramatic parallel rise of ΕοΕ: a series of observational studies reported an inverse association. In this review, we counter these arguments by providing further epidemiological data, which point out that this generalization might be rather incomplete. We also discuss the limitations of the existing studies evaluating a possible association. Furthermore, we provide current evidence on common pathogenetic components, which share both entities. In summary, the claim that H. pylori is protective against EoE is rather incomplete, and further mechanistic studies are necessary to elucidate a possible association.

Recent advances in potential targets for eosinophilic esophagitis treatments

Introduction: Diagnostic and therapeutic strategies in eosinophilic esophagitis (EoE) are constantly evolving. Recently, the improved understanding of EoE pathogenesis has led to identification of a variety of other potential targets that have never been considered before.Areas covered: In September 2019, we performed structured literature searches in Medline and PubMed, Cochrane meta-analyses, and abstracts of international congresses to review new potential therapeutic approaches for EoE.Expert opinion: The advent of omics disciplines has been helping in finding new molecular targets in EoE pathogenesis and may provide future guidance for deep phenotyping of the disease and therefore facilitate the possibility of personalized medicine. Interestingly, these new treatments should be focused on the restoration of epithelial barrier dysfunction, downregulation of specific molecular pathways of eosinophilic inflammation, and finally, prevention of esophageal remodeling. In this review, we highlight the most recent insights in EoE pathogenesis, which open new pathways for developing new therapeutic targets for clinical practice.

Future therapies for eosinophilic gastrointestinal disorders

OBJECTIVE

To review novel therapeutics in development for treatment of eosinophilic gastrointestinal disorders (EGIDs).

DATA SOURCES

Clinical trial data (clinicaltrials.gov) and literature search on PubMed.

STUDY SELECTIONS

Studies on treatment and clinical trials in EGIDs were included in this review.

RESULTS

During the past decade, significant progress has been made in understanding disease mechanisms in EGIDs. As a result, a variety of novel therapeutics have been developed for treatment of these disorders. Several monoclonal antibodies against targets, including interleukin (IL) 4, IL-5, IL-13, integrins, and siglec-8, have shown promise in early trials. Novel formulations of corticosteroids are also in development.

CONCLUSION

The field of EGID research has advanced rapidly, and disease-modifying therapeutics are closer to clinical application.

Association between endoscopic findings of eosinophilic esophagitis and responsiveness to proton pump inhibitors

Background and study aims  Endoscopic findings of esophageal eosinophilia sometimes localize to small areas of the esophagus. A previous study suggested that pathogenesis of localized-type eosinophilic esophagitis (LEoE) was associated with acid reflux. However, LEoE treatment outcomes have not been studied. We aimed to analyze the clinical and histologic significance of LEoE in comparison with diffuse-type eosinophilic esophagitis (DEoE). Patients and methods  This study included 106 patients with esophageal eosinophilia. Esophageal eosinophilia was defined as a condition where the maximum number of intraepithelial eosinophils was ≥ 15 per high-power field. LEoE was defined as an endoscopic lesion confined to one-third of the esophagus: upper, middle, or lower. Esophageal eosinophilia encompassing more than two-thirds of the esophagus was defined as DEoE. We retrospectively compared LEoE and DEoE in terms of clinical characteristics, histologic findings, and proportion of proton pump inhibitor (PPI) responders. Results  Of 106 patients, 12 were classified as having LEoE and 94 were classified as having DEoE. The proportion of asymptomatic patients was significantly higher in the LEoE group than the DEoE group (42 % vs 7 %, P  < 0.01). In the LEoE group, 10 patients (84 %) had endoscopic lesions in the lower esophagus. The maximum number of eosinophils did not differ between the groups (54 [24 - 71] for LEoE, 40 [20 - 75] for DEoE, P  = 0.65). The prevalence of PPI responders was significantly higher in the LEoE group than the DEoE group (100 % vs 63 %, P  = 0.01). Conclusion  LEoE can be a sign of good responsiveness to PPI therapy.

The Predictive Factors of Responsiveness to Proton Pump Inhibitor Therapy for Eosinophilic Esophagitis

Approximately half of patients with eosinophilic esophagitis (EoE) respond clinically and histologically to proton pump inhibitor (PPI) therapy. Although recent guidelines suggest that PPI-responders and non-responders were included in EoE, it is important to investigate the predictive factors of PPI- responsiveness. This study aimed to determine the rate of PPI- responders and compare the characteristics of PPI-responders and non-responders. Fifty-nine patients with esophageal eosinophilia received PPI therapy for eight weeks, and its efficacy was assessed. PPI- responsiveness was diagnosed based on the relief in symptoms and reduction of intraepithelial eosinophilic infiltration to <15 per high-power field (hpf) after PPI therapy. Multivariate analysis was performed to identify factors associated with PPI-responders. Of the 59 patients, 41 (69.5%) were diagnosed with PPI-responders. The rate of gastrointestinal (GI) screening in the indications for endoscopy was significantly higher in patients with PPI- responders than in those with non-responders. On multivariate analysis, GI screening and presence of reflux esophagitis was associated with an increased odds ratio (OR) of PPI-responders, but presence of rings with a decreased OR of PPI-responders. Presence of reflux esophagitis and absence of rings on endoscopy especially during GI screening might be significant predictive factors for PPI response in patients with EoE.

Baseline Gastrointestinal Eosinophilia Is Common in Oral Immunotherapy Subjects With IgE-Mediated Peanut Allergy

Rationale: Oral immunotherapy (OIT) is an emerging treatment for food allergy. While desensitization is achieved in most subjects, many experience gastrointestinal symptoms and few develop eosinophilic gastrointestinal disease. It is unclear whether these subjects have subclinical gastrointestinal eosinophilia (GE) at baseline. We aimed to evaluate the presence of GE in subjects with food allergy before peanut OIT.

Methods: We performed baseline esophagogastroduodenoscopies on 21 adults before undergoing peanut OIT. Subjects completed a detailed gastrointestinal symptom questionnaire. Endoscopic findings were assessed using the Eosinophilic Esophagitis (EoE) Endoscopic Reference Score (EREFS) and biopsies were obtained from the esophagus, gastric antrum, and duodenum. Esophageal biopsies were evaluated using the EoE Histologic Scoring System. Immunohistochemical staining for eosinophil peroxidase (EPX) was also performed. Hematoxylin and eosin and EPX stains of each biopsy were assessed for eosinophil density and EPX/mm² was quantified using automated image analysis.

Results: All subjects were asymptomatic. Pre-existing esophageal eosinophilia (>5 eosinophils per high-power field [eos/hpf]) was present in five participants (24%), three (14%) of whom had >15 eos/hpf associated with mild endoscopic findings (edema, linear furrowing, or rings; median EREFS = 0, IQR 0–0.25). Some subjects also demonstrated basal cell hyperplasia, dilated intercellular spaces, and lamina propria fibrosis. Increased eosinophils were noted in the gastric antrum (>12 eos/hpf) or duodenum (>26 eos/hpf) in 9 subjects (43%). EPX/mm² correlated strongly with eosinophil counts (r = 0.71, p < 0.0001).

Conclusions: Pre-existing GE is common in adults with IgE-mediated peanut allergy. Eosinophilic inflammation (EI) in these subjects may be accompanied by mild endoscopic and histologic findings. Longitudinal data collection during OIT is ongoing.

RNA sequencing confirms similarities between PPI-responsive oesophageal eosinophilia and eosinophilic oesophagitis

BACKGROUND

Although current American guidelines distinguish proton pump inhibitor-responsive oesophageal eosinophilia (PPI-REE) from eosinophilic oesophagitis (EoE), these entities are broadly similar. While two microarray studies showed that they have similar transcriptomes, more extensive RNA sequencing studies have not been done previously.

AIM

To determine whether RNA sequencing identifies genetic markers distinguishing PPI-REE from EoE.

METHODS

We retrospectively examined 13 PPI-REE and 14 EoE biopsies, matched for tissue eosinophil content, and 14 normal controls. Patients and controls were not PPI-treated at the time of biopsy. We did RNA sequencing on formalin-fixed, paraffin-embedded tissue, with differential expression confirmation by quantitative polymerase chain reaction (PCR). We validated the use of formalin-fixed, paraffin-embedded vs RNAlater-preserved tissue, and compared our formalin-fixed, paraffin-embedded EoE results to a prior EoE study.

RESULTS

By RNA sequencing, no genes were differentially expressed between the EoE and PPI-REE groups at the false discovery rate (FDR) ≤0.01 level. Compared to normal controls, 1996 genes were differentially expressed in the PPI-REE group and 1306 genes in the EoE group. By less stringent criteria, only MAPK8IP2 was differentially expressed between PPI-REE and EoE (FDR = 0.029, 2.2-fold less in EoE than in PPI-REE), with similar results by PCR. KCNJ2, which was differentially expressed in a prior study, was similar in the EoE and PPI-REE groups by both RNA sequencing and real-time PCR.

CONCLUSION

Eosinophilic oesophagitis and PPI-REE have comparable transcriptomes, confirming that they are part of the same disease continuum.

Emerging drugs for eosinophilic esophagitis

INTRODUCTION

Eosinophilic esophagitis (EoE) is rare but incidence and prevalence is increasing. EoE is characterized by eosinophilic inflammation of the esophagus causing gastrointestinal symptoms such as abdominal pain, vomiting, reflux, dysphagia, and food impactions. If untreated, remodeling and fibrosis of the esophagus can occur and stricture formation may result. Current treatment options are limited to food-restriction diets or medications including proton pump inhibitors (PPIs) or swallowed corticosteroids. Significant progress has been made in understanding the underlying mechanisms of EoE allowing for development of drugs that target specific points in EoE pathways. Investigation of these drugs is early with few controlled studies, but many show promise as future treatments. Areas covered: This review will provide an up to date discussion of current therapies and investigational drugs for EoE. Articles used in this review were retrieved from PubMed. Ongoing or completed clinical trials were obtained through clinicaltrials.gov and review of the PharmaProjects database. Expert Opinion: Multiple therapeutic targets have been identified and several have shown efficacy. Work is needed to define appropriate trial outcome measures. Collaboration between government agencies, patient advocacy groups, and investigator-led consortia is critical for completing new clinical trials which should pave the way for new therapies in clinical practice.

Management of Eosinophilic Esophagitis Based on Pathophysiological Evidence

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

Eosinophilic esophagitis: unclear roles of IgE and eosinophils

Eosinophilic esophagitis (EoE) is a chronic inflammatory disease of the oesophagus. Recognized as a distinct entity only two decades ago, the emergence of the disease along with the availability of new technologies has rapidly opened new research avenues and outlined the main features of the pathogenesis of EoE. Yet, each advance in our understanding of the disease has raised new questions about the previous consensus. Currently, new subsets of the disease challenge our diagnostic criteria. For instance, it was believed that EoE did not respond to proton pump inhibitor (PPI) therapy; however, it has now been shown that a substantial proportion of EoE patients indeed respond to PPIs. In addition, a new subset of patients not even presenting eosinophil infiltrates in the oesophagus has also been described. Moreover, approaches for better understanding the heritability of the disease bring into question the dogma of predominant genetic involvement. Furthermore, the specificity and sensitivity of allergy testing for targeted food avoidance is highly controversial, and the production of specific antibodies in EoE now includes IgG4 in addition to IgE. In conclusion, EoE is perceived as 'a moving target' and the aim of this review was to summarize the current understanding of EoE pathogenesis.

Similarities and differences among eosinophilic esophagitis, proton-pump inhibitor-responsive esophageal eosinophilia, and reflux esophagitis: comparisons of clinical, endoscopic, and histopathological findings in Japanese patients

BACKGROUND

Esophageal eosinophilia is classified as either eosinophilic esophagitis (EoE) or proton-pump inhibitor-responsive esophageal eosinophilia (PPI-REE), depending on the response to PPI treatment. The aim of this study was to compare the clinical, endoscopic, and histopathological findings of EoE and PPI-REE in Japanese patients. In addition, the characteristics of these cases were compared with those of reflux esophagitis (RE) cases.

METHODS

Eleven patients diagnosed with EoE, 16 with PPI-REE, and 39 with RE, who were all consecutively examined from 2005 to 2015 at Shimane University Hospital, were enrolled. Clinical, endoscopic, and histopathological esophageal findings in these groups were retrospectively examined and compared.

RESULTS

The differences in the clinical characteristics of EoE and PPI-REE were not remarkable, though patients with EoE and PPI-REE were younger, presented a higher prevalence of allergic comorbidities, and complained of symptoms of dysphagia more frequently than those with RE. The only noteworthy differences between EoE and PPI-REE were more frequent reports of asthma (36.4 vs. 2.6 %) and food allergy (27.3 vs. 0 %) by patients with EoE (P < 0.05, P < 0.05, respectively). Endoscopic findings in patients with EoE and PPI-REE were similar, with the presence of esophageal erosions in a small percentage of PPI-REE cases being the only difference. There were no histopathological differences between EoE and PPI-REE.

CONCLUSIONS

Comparisons of clinical, endoscopic, and histopathological findings between EoE and PPI-REE showed that these two types have similar characteristics, though EoE patients showed a higher atopic background. Predicting PPI responsiveness in cases with esophageal eosinophilia is difficult and requires further investigation.

Presence of intraepithelial food antigen in patients with active eosinophilic oesophagitis

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Oesophageal narrowing on barium oesophagram is more common in adult patients with eosinophilic oesophagitis than PPI-responsive oesophageal eosinophilia

BACKGROUND

To date there have been no clear features that aid in differentiating patients with eosinophilic oesophagitis (EoE) from PPI-responsive oesophageal eosinophilia (PPI-REE). However, barium swallow roentgenography is a more sensitive and specific measure to detect subtle fibrostenotic remodeling changes present in EoE. We aim to characterise any clinical, endoscopic, histiological or barium roentgenographic differences between EoE and PPI-REE.

AIM

To characterise any clinical, endoscopic, histiological or barium roentgenographic differences between EoE and PPI-REE.

METHODS

We performed a retrospective cohort analysis on data collected from a tertiary referral centre population from 2010 to 2015. Data from 66 patients with EoE and 28 patients with PPI-REE were analysed. Cases were adults who met consensus guidelines for EOE, and had a barium swallow study within 6 months of the index endoscopy. Clinical, endoscopic, histiological and barium swallow findings were collected.

RESULTS

Patients with EoE reported similar characteristics as PPI-REE patients, except EoE patients were younger (35.6 vs. 46.6 years; P = 0.011), had earlier symptom onset (29.0 vs. 38.0 years; P = 0.026), and smaller oesophageal diameters on barium swallow (19.5 mm vs. 20; P = 0.042). Patients with EoE were more likely to have distal strictures (EoE 77% vs. 25%; P = 0.02) and, importantly, a greater likelihood of small calibre oesophagus (51.5% vs. 17.9%; P = 0.002). Moreover, EoE patients had a higher probability of developing small calibre oesophagus after 20 years of symptoms (72.3% vs. 30.2%; P = 0.074) compared to PPI-REE patients.

CONCLUSIONS

When compared with eosinophilic oesophagitis, PPI-REE patients demonstrate findings that suggest PPI-responsive oesophageal eosinophilia to be a later onset, less aggressive form of oesophageal stricturing disease than eosinophilic oesophagitis.

The role of proton pump inhibitor therapy in the management of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic esophageal disease characterized by a Th2 inflammatory response triggered by food/environmental allergens. Solid data confirm that up to half of patients with suspected EoE achieve complete remission on proton pump inhibitors (PPI) therapy. This disease phenotype is currently labelled as PPI-responsive esophageal eosinophilia (PPI-REE). Albeit initially believed to represent gastro-esophageal reflux disease (GERD), evolving evidence has underscored that PPI-REE and EoE show a significant overlap regarding clinic, endoscopic, histologic, Th2 immune-mediated inflammation and gene expression features. Moreover, PPI therapy can effectively reverse Th2 inflammation and the EoE transcriptome expression in PPI-REE patients. Therefore, EoE and PPI-REE likely represent a common allergic disorder, where PPI therapy should be considered a short- and long-term therapeutic asset, along with diet and topical steroids.

Proton pump inhibitor-responsive oesophageal eosinophilia: an entity challenging current diagnostic criteria for eosinophilic oesophagitis

Consensus diagnostic recommendations to distinguish GORD from eosinophilic oesophagitis (EoE) by response to a trial of proton pump inhibitors (PPIs) unexpectedly uncovered an entity called 'PPI-responsive oesophageal eosinophilia' (PPI-REE). PPI-REE refers to patients with clinical and histological features of EoE that remit with PPI treatment. Recent and evolving evidence, mostly from adults, shows that patients with PPI-REE and patients with EoE at baseline are clinically, endoscopically and histologically indistinguishable and have a significant overlap in terms of features of Th2 immune-mediated inflammation and gene expression. Furthermore, PPI therapy restores oesophageal mucosal integrity, reduces Th2 inflammation and reverses the abnormal gene expression signature in patients with PPI-REE, similar to the effects of topical steroids in patients with EoE. Additionally, recent series have reported that patients with EoE responsive to diet/topical steroids may also achieve remission on PPI therapy. This mounting evidence supports the concept that PPI-REE represents a continuum of the same immunological mechanisms that underlie EoE. Accordingly, it seems counterintuitive to differentiate PPI-REE from EoE based on a differential response to PPI therapy when their phenotypic, molecular, mechanistic and therapeutic features cannot be reliably distinguished. For patients with symptoms and histological features of EoE, it is reasonable to consider PPI therapy not as a diagnostic test, but as a therapeutic agent. Due to its safety profile, ease of administration and high response rates (up to 50%), PPI can be considered a first-line treatment before diet and topical steroids. The reasons why some patients with EoE respond to PPI, while others do not, remain to be elucidated.

Comparison of eotaxin-3 biomarker in patients with eosinophilic oesophagitis, proton pump inhibitor-responsive oesophageal eosinophilia and gastro-oesophageal reflux disease

BACKGROUND

Proton pump inhibitor-responsive oesophageal eosinophilia (PPI-REE) is a recently described entity which resembles oeosinophilic oesophagitis (EoE), yet responds to acid suppressive treatment.

AIM

To determine whether EoE shares similar staining features with PPI-REE or with gastro-oesophageal reflux disease (GERD).

METHODS

This retrospective study consisted of patients with an established diagnosis of EoE, PPI-REE, or GERD identified from a database during a 1-year period. Immunohistochemistry (IHC) analysis was performed specifically targeting eotaxin-3 antibodies. All sections were qualitatively (intensity) and quantitatively (percentage of cells stained) assessed independently by two blinded pathologists.

RESULTS

The cohort consisted of three groups of patients: EoE (n = 22), PPI-REE (n = 23) and GERD (n = 23) for a total of 68 patients. Study demographics included mean age 39 (14) years, 75% male and 77% Caucasian. There was a significant difference in the eotaxin-3 staining among EoE, PPI-REE and GERD groups [mean score (s.d.): 1.2 (1.2), 0.8 (1.0), 0.3 (0.7), P = 0.006]. Staining scores of EoE patients were significantly higher compared with GERD (P = 0.002) and a trend towards significance was seen between EoE and PPI-REE (P = 0.054). There was also a significant difference in EoE staining intensity score among the three groups (P = 0.006). Intensity scores of EoE were significantly higher compared with GERD [1.0 (0.9) vs. 0.22 (0.52), P < 0.001]. There was no significant difference between EoE and PPI-REE groups [1.0 (0.0) vs. 0.52 (0.75) P = 0.094].

CONCLUSIONS

A difference in eotaxin-3 staining was seen in the three groups of patients with oesophageal eosinophilia. Eotaxin-3 can distinguish EoE from GERD, but not from proton pump inhibitor responsive-oesophageal eosinophilia.