Clinical tolerance in eosinophilic esophagitis

Persistent esophageal changes after histologic remission in eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is characterized by persistent or relapsing allergic inflammation, and both clinical and histologic features of esophageal inflammation persist over time in most individuals. Mechanisms contributing to EoE relapse are not understood, and chronic EoE-directed therapy is therefore required to prevent long-term sequelae.

OBJECTIVE

We investigated whether EoE patients in histologic remission have persistent dysregulation of esophageal gene expression.

METHODS

Esophageal biopsy samples from 51 pediatric and 52 adult subjects with EoE in histopathologic remission (<15 eosinophils per high-power field [eos/hpf]) and control (48 pediatric and 167 adult) subjects from multiple institutions were subjected to molecular profiling by the EoE diagnostic panel, which comprises a set of 94 esophageal transcripts differentially expressed in active EoE.

RESULTS

Defining remission as <15 eos/hpf, we identified 51 and 32 differentially expressed genes in pediatric and adult EoE patients compared to control individuals, respectively (false discovery rate < 0.05). Using the stringent definition of remission (0 eos/hpf), the adult and pediatric cohorts continued to have 18 and 25 differentially expressed genes (false discovery rate < 0.05). Among 6 shared genes between adults and children, CDH26 was upregulated in both children and adults; immunohistochemistry demonstrated increased cadherin 26 staining in the epithelium of EoE patients in remission compared to non-EoE controls. In the adult cohort, POSTN expression correlated with the endoscopic reference system score (Spearman r = 0.35, P = .011), specifically correlating with the rings' endoscopic reference system subscore (r = 0.53, P = .004).

CONCLUSION

We have identified persistent EoE-associated esophageal gene expression in patients with disease in deep remission. These data suggest potential inflammation-induced epigenetic mechanisms may influence gene expression during remission in EoE and provide insight into possible mechanisms that underlie relapse in EoE.

Long-Term Outcomes of the Six-Food Elimination Diet and Food Reintroduction in a Large Cohort of Adults With Eosinophilic Esophagitis

INTRODUCTION

Eosinophilic esophagitis (EoE) is an immune-mediated inflammatory condition with tissue eosinophilia resulting in esophageal dysfunction. The six-food elimination diet (SFED) is an EoE treatment approach that removes milk, wheat, soy, eggs, tree nuts/peanuts, and fish/shellfish. After histologic remission, food reintroduction occurs to identify a food trigger. Outcomes from large series of adults undergoing SFED and food reintroduction as clinical care are not known.

METHODS

A retrospective review (2006-2021) of adult patients with EoE from an academic center was completed. Patients were classified as full responders (<15 eos/hpf) after SFED. If reintroduction was pursued, food triggers identified were recorded.

RESULTS

Two hundred thirteen patients completed SFED. One hundred fifteen patients (54%) had response <15 eos/hpf after SFED. Seventy-seven percent of responders had symptom improvement. Thirty-two percent of initial nonresponders underwent repeat dietary elimination. Fifty-eight percent of patients (n = 123) achieved <15 eos/hpf after either initial or extended SFED. Seventy-eight percent of responders underwent food reintroduction. Sixty-nine percent had 1 food trigger identified, 24% had 2 allergens identified, and 4% had 3 allergens identified. The most common food triggers identified were milk, wheat, and soy.

DISCUSSION

This study describes the largest cohort reported of adult patients with EoE completing SFED with food reintroduction. The overall SFED histologic response was 54%, which increased to 58% with 1 additional round of dietary therapy, suggesting that 31% may respond in a second attempt. Most patients who completed food reintroduction had a single food trigger identified. Dietary elimination with specific food trigger identification is a feasible alternative to medical therapy for adults with EoE.

A Gap in Care Leads to Progression of Fibrosis in Eosinophilic Esophagitis Patients

BACKGROUND & AIMS

There are few data assessing disease progression in eosinophilic esophagitis (EoE) after diagnosis. We aimed to determine outcomes and assess for progression of fibrosis in patients with EoE with a gap in their regular care.

METHODS

In this retrospective cohort study of newly diagnosed patients with EoE, a "gap" in care was defined as ≥2 years without medical contact for EoE. For inclusion, a gap in care and both pre- and post-gap endoscopies were required. Patients with and without a gap were compared. Data were also compared in gap patients before the gap and after EoE care resumed, and progression of fibrosis and predictors were assessed.

RESULTS

Of 701 patients with EoE, 95 (14%) had a gap in care (mean time without care, 4.8 ± 2.3 years). Post-gap, 12% presented with food impaction requiring emergency evaluation. Compared with pre-gap, patients post-gap had higher endoscopic severity (2.4 vs 1.5; P < .001) and smaller esophageal diameters (11.0 vs 12.7 mm; P = .04). Strictures were more prevalent with longer gap time (P < .05 for trend). Each additional year of gap time increased odds of stricture by 26%, even after accounting for pre-gap dilation. Additionally, of 67 patients without pre-gap fibrosis, 25 (37%) had at least one fibrotic feature (stricture, narrowing, or requiring dilation) post-gap.

CONCLUSIONS

A gap in care of ≥2 years in patients with EoE was associated with signs of increased disease activity, and progression to fibrostenosis was noted, particularly with longer gaps in care. Because EoE can progress to fibrosis even after diagnosis, regular care in patients with EoE is required, perhaps at intervals <2 years.

Current treatment options and long-term outcomes in patients with eosinophilic esophagitis

INTRODUCTION

Dietary and pharmacological (proton pump inhibitors, swallowed topical corticosteroids) therapies are effective for induction of clinical and histological remission of eosinophilic esophagitis. However, data evaluating their long-term efficacy and safety is limited.

AREAS COVERED

Since eosinophilic esophagitis is chronic, clinical, endoscopic, and histological features usually recur when successful treatments are stopped. In untreated patients, persistent esophageal eosinophilic inflammation may progress to fibrostenosis over time, giving place to strictures and narrow-caliber esophagi. This article comprehensively reviews available data on long-term maintenance of eosinophilic esophagitis with pharmacological and dietary treatment. It also discusses limitations re: available literature and outlines data gaps on adherence to therapy and monitoring disease activity in the long-term.

EXPERT OPINION

Evidence indicates that long-term maintenance therapy may decrease the risk of esophageal stricture, food bolus impaction, and need for dilation in patients with eosinophilic esophagitis. Further knowledge on eosinophilic esophagitis phenotypes is needed to ascertain who will benefit best from sustained therapy. Unanswered questions include an adequate definition for sustained remission, best strategies for maintenance drugs and diets, enhancement of treatment adherence, and proper monitoring for long-term surveillance.

Eosinophilic esophagitis in children: Updates and practical aspects of management for allergists in a non-tertiary care private practice setup

Background: Eosinophilic esophagitis (EoE) is a chronic immune and/or antigen-mediated disease characterized by eosinophilic infiltration of mucosa (≥15 eosinophils per high power field) without any secondary etiology. Non-immunoglobulin E mediated mechanisms predominate in EoE. Objective: This review concentrated on a stepwise approach for the allergist working in non-tertiary care private practice. Methods: A medical literature search that focused on several areas of the latest developments in the diagnosis and management of EoE was conducted. Results: There has been a steady increase in the prevalence and incidence of EoE. Clinical symptoms can vary from dysphagia to failure to thrive, depending on the age at presentation; some children develop adaptive behaviors to compensate for dysphagia, such as food preferences and slow eating. The diagnosis is based on a high index of clinical suspicion and is confirmed with endoscopy with biopsies after ruling out other causes of esophageal eosinophilia. Treatment options may include dietary therapy, pharmacologic therapies, or combination therapy. Therapeutic options may also include endoscopic dilation for stricturing disease. Conclusion: Providers should be aware of recent recommendation changes in the diagnostic workup, the role of skin-prick testing, and role of the proton-pump inhibitor as first-line therapy for EoE. Also, clinicians should be aware of the emerging role of empiric dietary therapy as a preferable therapeutic option when compared with the testing-directed diet and the elemental diet. Furthermore, topical glucocorticoid therapies are available, and new developing therapies are being investigated. Reevaluation of esophageal mucosa with biopsies is required approximately 2 months after therapy for a response and after a change in therapies to confirm continued resolution.

Viral Induced Effects on a Vulnerable Epithelium; Lessons Learned From Paediatric Asthma and Eosinophilic Oesophagitis

The epithelium is integral to the protection of many different biological systems and for the maintenance of biochemical homeostasis. Emerging evidence suggests that particular children have epithelial vulnerabilities leading to dysregulated barrier function and integrity, that resultantly contributes to disease pathogenesis. These epithelial vulnerabilities likely develop in utero or in early life due to various genetic, epigenetic and environmental factors. Although various epithelia are uniquely structured with specific function, prevalent allergic-type epithelial diseases in children potentially have common or parallel disease processes. These include inflammation and immune response dysregulation stemming from atypical epithelial barrier function and integrity. Two diseases where aetiology and pathogenesis are potentially linked to epithelial vulnerabilities include Paediatric Asthma and Eosinophilic Oesophagitis (EoE). For example, rhinovirus C (RV-C) is a known risk factor for paediatric asthma development and is known to disrupt respiratory epithelial barrier function causing acute inflammation. In addition, EoE, a prevalent atopic condition of the oesophageal epithelium, is characterised by similar innate immune and epithelial responses to viral injury. This review examines the current literature and identifies the gaps in the field defining viral-induced effects on a vulnerable respiratory epithelium and resulting chronic inflammation, drawing from knowledge generated in acute wheezing illness, paediatric asthma and EoE. Besides highlighting the importance of epithelial structure and barrier function in allergic disease pathogenesis regardless of specific epithelial sub-types, this review focuses on the importance of examining other parallel allergic-type disease processes that may uncover commonalities driving disease pathogenesis. This in turn may be beneficial in the development of common therapeutics for current clinical management and disease prevention in the future.

Medical Management of Eosinophilic Esophagitis in Pediatric Patients

Eosinophilic esophagitis is an immune-mediated allergic disease of the esophagus that affects pediatric patients of all ages. The diagnosis is made by esophagogastroduodenoscopy demonstrating eosinophilic infiltrate of the esophagus. Approaches to treatment involve proton pump inhibitors (PPIs), swallowed topical steroid preparations, as well as dietary elimination. In this review we discuss the evidence and efficacy of each of these approaches.

Peripheral markers of allergen-specific immune activation predict clinical allergy in eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a T-cell-mediated disease that is caused by specific foods and results in esophageal dysfunction. Existing allergy testing modalities are not helpful when attempting to identify EoE-causal foods necessitating empiric food elimination and recurrent endoscopy. The goal of this study was to identify and compare allergen-specific immune features that can be assayed in a minimally invasive manner to predict clinical food allergy in EoE.

METHODS

We obtained blood samples from control subjects (n = 17), subjects with clinical EoE milk allergy (n = 17), and subjects with immunoglobulin E-mediated milk allergy (n = 9). We measured total and milk-specific plasma immunoglobulin G (IgG)4 levels and peripheral memory CD4⁺ T helper (T_H ) cell proliferation and cytokine production after stimulation with endotoxin-depleted milk proteins. Sensitivity and specificity for predicting clinical EoE milk allergy were calculated and compared between approaches.

RESULTS

Total and milk-specific IgG4 levels were not significantly different between control subjects and subjects with clinical EoE milk allergy. Stimulation with milk proteins caused T_H lymphocytes from subjects with clinical EoE milk allergy to proliferate more (%P1 of 38.3 ± 4.6 vs. 12.7 ± 2.8, p < 0.0001), and produce more type 2 cytokines (%IL-4⁺ of 33.7 ± 2.8 vs. 6.9 ± 1.6, p < 0.0001) than cells from control subjects. Milk-dependent memory T_H -cell proliferation (sensitivity and specificity of 88% and 82%, respectively) and interleukin 4 (IL-4) production (sensitivity and specificity of 100%) most strongly predicted clinical EoE milk allergy.

CONCLUSIONS

Peripheral markers of allergen-specific immune activation may be useful in identifying EoE-causal foods. Assaying milk-dependent IL-4 production by circulating memory T_H lymphocytes most accurately predicts clinical EoE milk allergy.

RNA sequencing identifies global transcriptional changes in peripheral CD4+ cells during active oesophagitis and following epicutaneous immunotherapy in eosinophilic oesophagitis

OBJECTIVE

There are no disease-modifying therapies for the treatment of eosinophilic oesophagitis (EoE), which is driven by non-IgE-mediated allergic inflammation. A recent clinical trial of milk epicutaneous immunotherapy (EPIT) has shown initial promise, with 47% of treated EoE patients tolerating milk without recurrence of disease. Mechanisms of EPIT in EoE have not been studied in humans. Here, we identify transcriptional changes in the peripheral CD4+ T-cell compartment during active EoE and following EPIT.

METHODS

RNA isolation, sequencing and integrative data analysis were performed on peripheral CD4+ T cells isolated from 15 of 20 patients enrolled in a clinical trial of EPIT for EoE. Gene expression changes in peripheral CD4+ T cells were examined during diet therapy and following trial of milk antigen EPIT.

RESULTS

We identify 244 differentially expressed genes in peripheral blood CD4+ cells of EoE patients consuming versus those eliminating milk, and 129 DEGs in CD4+ cells were isolated after EPIT versus after placebo (FDR ≤ 0.05). Gene set enrichment analysis identifies enrichment of hallmark interferon-α and interferon-γ response pathways in peripheral CD4+ T cells from EoE patients during active disease on a milk-containing diet. We demonstrate overlap of this gene signature with the altered gene expression signature seen in EoE patient biopsy tissue. EPIT therapy response is associated with significant enrichment in pathways related to T-cell receptor signalling (P = 1.16 × 10-14), antigen presentation and costimulation, and cytokine signalling (P = 1.11 × 10-16), as well as upregulation of genes associated with regulatory T-cell function.

CONCLUSIONS

EoE is associated with distinct global transcriptional changes in CD4+ T cells, one feature of which is an IFN response signature. Clinically favorable response to EPIT is likely multifactorial but is associated with a distinct transcriptional profile in peripheral CD4+ cells supporting the hypothesis that EPIT alters peripheral CD4+ responses in EoE patients.

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

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

Effectiveness of allergy testing in milk induced eosinophilic esophagitis. Description and follow-up of patients

INTRODUCTION

Eosinophilic esophagitis (EoE) is a chronic, local immune-mediated esophageal disease that has been on the increase lately. There is currently enough evidence to conclude that EoE is an allergic disorder triggered by food allergens, with cow's milk (CM) being the most frequent. Dietary intervention is the first-line approach. This study aimed to assess the clinical characteristics, the diagnostic method, and the prognosis of patients whose culprit food was CM, as opposed to other triggers.

METHODS

Children with EoE evaluated in our pediatric Allergy Department were retrospectively studied from 2004 to 2017. We collected clinical variables, diagnostic protocol, treatment, and follow-up data. We compared patients whose culprit food was CM and patients with EoE due to other causative agents.

RESULTS

We analyzed 31 children with EoE and found the causative food to be cow's milk in 14 (45%). Clinical characteristics were similar in patients with EoE due to milk or any other cause. Eight of 14 patients with milk-induced EoE (57.14%) presented positive skin prick test results against cow's milk. All patients had positive IgE against cow's milk. None of the patients had any other food as the trigger. The median follow-up was 2.68 years (6 months to 9 years) with initial remission of 100%.

CONCLUSION

Testing-based elimination diets effectively treated all of the patients with milk-induced EoE. The advantage of this diagnostic protocol is that it required a mean of only two foods to be tested, significantly smaller number than in empiric diets.

Approaches and Challenges to Management of Pediatric and Adult Patients With Eosinophilic Esophagitis

Treatment of eosinophilic esophagitis has progressed from elemental formula for children and esophageal dilation for adults to selective exclusion of food triggers and swallowed topical corticosteroids. Management guidelines are available from the American Gastroenterological Association and the Joint Task Force on Allergy Immunology Practice Parameters. We cannot, however, evaluate the efficacy of treatments without a definition of response. We propose a treat-to-target approach, based on symptoms and findings from endoscopy and histology. This approach addresses dissociations between outcomes, such as symptom persistence despite normalization of histologic features and symptom resolution after esophageal dilation despite histologic features of active disease. Eosinophilic esophagitis can now be treated with biologic agents that target specific immune pathways, and findings from prospective trials have indicated that less-restrictive, empiric, elimination diets can be effective and reduce the need for repeated endoscopic assessment of disease activity during food reintroduction. We also discuss eosinophilic esophagitis subtypes, factors associated with disease, and advances in management.

Sustained Remission of Eosinophilic Esophagitis Following Discontinuation of Dietary Elimination in Children

Eosinophilic esophagitis (EoE), when left untreated, may progress from an inflammatory to a fibrostenotic phenotype. Inflammation generally recurs after treatment withdrawal. Thus, long-term treatment has been recommended. Here, we describe a cohort of children with EoE who achieved clinical and histologic remission with elimination diets, and maintained sustained untreated remission (SUR) despite re-introduction of all eliminated food allergens.

Phenotypes and endotypes in eosinophilic esophagitis

OBJECTIVE

To improve understanding of the heterogeneous presentation of eosinophilic esophagitis (EoE), and its different potential phenotypes and endotypes.

DATA SOURCES

We reviewed studies addressing EoE genetics, risks, natural history, treatment, phenotype, or endotype to assess data relating to differences in the presentation of EoE in children and adults. This review was restricted to articles in the English language.

STUDY SELECTIONS

Data source abstracts, pertinent articles, and book chapters meeting the objectives were critically reviewed.

RESULTS

Data to support differing phenotypes and endotypes in EoE are emerging, but findings are based on multiple studies and therefore sometimes incomparable. Like other atopic disorders EoE is a complex disease with diverse clinical presentations (phenotypes) based on response to therapy, natural history, and association with atopic comorbidities. Different pathogenetic mechanisms (endotypes) may drive the multiple phenotypes. T Helper type 2 inflammation, epithelial barrier defects, enhanced fibrosis, and association with rare monogenetic diseases are the most described endotypes in EoE.

CONCLUSION

Eosinophilic esophagitis is an atopic disorder that is increasing in prevalence and can be difficult to treat. Better understanding of phenotypes and endotypes in EoE may enable future care to be individualized more effectively, resulting in shorter time to remission and fewer endoscopies.

Evaluation of long-term course in children with eosinophilic esophagitis reveals distinct histologic patterns and clinical characteristics

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic and increasingly prevalent antigen-driven disease. There is a paucity of information on long-term course in children.

OBJECTIVE

We sought to understand the longitudinal trajectory of pediatric EoE during routine clinical care.

METHODS

We prospectively enrolled children into an EoE database and reviewed their medical and pathologic records over 13 years.

RESULTS

From 2011 to 2015, 146 children with EoE seen for their first visit at our center had 2 or more years of follow-up and 3 or more endoscopies over an average follow-up period of 5.13 years (range, 2-13 years). Longitudinal eosinophilic inflammation during treatment demonstrated 3 patterns over time. Children with less than 15 eosinophils/high-power field (hpf) for greater than 75% of their follow-up period were termed continuous responders (CRs). Children with waxing and waning inflammation of less than 15 eosinophils/hpf for less than 75% but 25% or more of the follow-up period were termed intermittent responders (IRs). Nonresponders (NRs) were defined as having less than 15 eosinophils/hpf for less than 25% of their follow-up. Fifty-nine (40%) of 146 patients were CRs, 65 (45%) of 146 were IRs, and 22 (15%) of 146 were NRs. CRs differed from IRs and NRs on the parameter of male/female ratio (1:1 in CRs, 4:1 in IRs, and 6:1 in NRs; P < .001) and in their initial response to any therapy, including proton pump inhibitors (P < .001). Endoscopic severity correlated with esophageal eosinophilia (r = 0.73, P < .001). On multivariate analysis, female sex and initial therapeutic response to medications or elimination diet were associated with long-term control of esophageal eosinophilia.

CONCLUSIONS

Long-term pediatric EoE followed 3 different longitudinal trajectories of inflammation. The long-term histologic groups differed significantly in biological sex and initial therapeutic response.

One-year outcomes in children with eosinophilic esophagitis

BACKGROUND AND AIMS

Despite rising incidence of eosinophilic esophagitis (EoE), data on the follow-up and treatment outcomes in pediatric patients are scarce. Therefore, the aim of this study was to present data on the treatment outcomes in children diagnosed with EoE who were treated in a tertiary medical center.

PATIENTS AND METHODS

A retrospective study involving patients younger than 18 years who were diagnosed with EoE in our center between January 2011 and June 2017.

RESULTS

Thirty-two patients met inclusion criteria and were followed up for a mean of 3 years (range 0.5-6.8). Six months after the diagnosis, 28 (87.5%) children were still followed up; 21 (75%) were in clinical remission, including 10 (36%) who were in histological remission. After 12 months, 27 patients were still followed up; 21 (78%) achieved clinical remission, including 10 (37%) with histological remission. During follow-up, three patients developed gastroesophageal reflux disease (GERD). There was no difference in body mass index (BMI) Z score between baseline and 12 months follow-up (median - 0.3 vs - 0.3 SD, p = 0.862).

CONCLUSIONS

Absence of symptoms does not indicate mucosal healing; therefore, patients should be followed up endoscopically. Additionally, despite restricted diet, nutritional status remains unaffected. Finally, patients with EoE can develop significant GERD even years after the EoE diagnosis.

The Journal of Allergy and Clinical Immunology: In Practice 2018 Highlights

A large number of clinically impactful studies and reviews were published in this journal in 2018. This article provides highlights of the original research published in 2018 issues of The Journal of Allergy and Clinical Immunolgy: In Practice on the subjects of anaphylaxis, asthma, dermatitis, drug allergy, eosinophilic disorders, food allergy, immune deficiency, rhinitis, and urticaria/angioedema and mast cell disorders. Within each topic, practical aspects of diagnosis and management are emphasized. Treatments discussed include lifestyle modifications, allergen avoidance therapy, positive and negative effects of pharmacologic therapy, and various forms of immunologic and desensitization management. We hope this review will help readers consolidate and use this extensive and practical knowledge for the benefit of patients.

Pediatric eosinophilic esophagitis: updates for the primary care setting

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Allergic components of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a disorder of increasing prevalence worldwide, causing clinical symptoms of vomiting, failure to thrive, and dysphagia and complications of esophageal remodeling with strictures and food impactions. Molecular profiling demonstrates EoE to be an eosinophil-predominant disorder with a TH2 cytokine profile reminiscent of other allergic diseases, such as asthma, allergic rhinitis, and atopic dermatitis. Environmental antigens in the form of foods and aeroallergens induce eosinophil, basophil, mast cell, and T-cell infiltration. Pathogenesis depends on local epithelial immune activation with production of thymic stromal lymphopoietin and eotaxin-3. Complications mirror asthmatic airway pathogenesis, with increases in subepithelial collagen deposition, angiogenesis, and smooth muscle hypertrophy. The removal of instigating antigens, especially foods, causes disease resolution in more than 50% of adults and children. The prevalence of concurrent atopic disorders in patients with EoE and the need to control antigen-specific TH2 inflammation underscore the importance of testing for allergens and treating the entire atopic subject to control the potential interplay between organ-specific allergic responses.

The role of maintenance therapy in eosinophilic esophagitis: who, why, and how?

In patients with eosinophilic esophagitis (EoE) who do not respond to proton pump inhibitors, initial anti-inflammatory/anti-eosinophilic treatment is with either topical corticosteroids or dietary elimination. A large body of literature supports the efficacy of these approaches, with histologic response rates in the 50-90% range for steroids and 70% range for the six-food elimination diet. However, these studies are almost all short-term and data evaluating long-term safety and efficacy of either treatment are limited. Nevertheless, because EoE is chronic, symptomatic, endoscopic, and histologic disease activity recurs when successful treatments are stopped. An emerging body of data also suggest that left untreated, persistent eosinophilic esophageal inflammation may progress to fibrostenosis over time. Therefore, maintenance therapy in EoE is intuitively attractive. This paper reviews the rationale for maintenance treatment in EoE, the available long-term pharmacologic and dietary response data for EoE, and discusses who may benefit the most from ongoing treatment. While all patients with EoE can be offered maintenance treatment, this option should be strongly recommended in patients with severe disease phenotypes or complications, including malnutrition or failure to thrive, esophageal fibrostenosis, strictures requiring dilation, recurrent food bolus impaction, history of perforation, and symptoms that recur quickly after treatment discontinuation. In all EoE patients, regular follow-up is also advised.