Glucocorticoid-regulated genes in eosinophilic esophagitis: a role for FKBP51

Validation of Epigenetic Markers for the Prediction of Response to Topical Corticosteroid Treatment in Eosinophilic Esophagitis

INTRODUCTION

We previously identified 18 CpG methylation biomarkers associated with treatment response to topical corticosteroids (tCS) in eosinophilic esophagitis (EoE). In this study, in an independent cohort, we assessed the validity of these CpG sites as treatment response biomarkers.

METHODS

DNA was extracted from prospectively biobanked esophageal biopsies from patients with newly diagnosed EoE enrolled in a randomized trial of 2 tCS formulations. Histologic response was defined as <15 eosinophils per high-power field. Pretreatment DNA methylation was assayed on the Illumina Human MethylationEPIC BeadChip. Logistic regression and area under the receiver operating characteristic curve analyses, adjusting for chip, position on the chip, age, sex, and baseline eosinophil count, were computed to test for an association between DNA methylation and treatment response at the 18 previously identified CpG sites.

RESULTS

We analyzed 88 patients (58 histologic responders, 30 nonresponders), with a mean age of 38 ± 16 years, 64% male, 97% White race. Of the 18 CpG sites, 13 met quality control criteria, and 3 were associated with responder status ( P < 0.012), including sites within UNC5B (cg26152017), ITGA6 (cg01044293), and LRRC8A (cg13962589). All 3 showed evidence of reduced methylation in treatment responders, consistent with the original discovery associations. The predictive probability for nonresponse with all 3 CpG sites was strong (area under the receiver operating characteristic curve = 0.79).

DISCUSSION

We validated epigenetic biomarkers (CpG methylation sites) for the prediction of tCS response in patients with EoE in an independent population. While not all previously identified markers replicated, 3 demonstrated a relatively high predictive probability for response to treatment and hold promise for guiding tCS treatment in EoE.

Genetic and Molecular Contributors in Eosinophilic Esophagitis

PURPOSE OF REVIEW

Eosinophilic esophagitis (EoE) is an allergic inflammatory esophageal disorder with a complex underlying genetic and molecular etiology. The interest of the scientific community in EoE has grown considerably over the past three decades, and the understanding of the genetic and molecular mechanisms involved in this disease has greatly increased.

RECENT FINDINGS

In this article, we aim to provide both historic aspects and updates on the recent genetic and molecular advances in the understanding of EoE. Although EoE is a relatively newly described disorder, much progress has been made toward identifying the genetic and molecular factors contributing to the disease pathogenesis by a variety of approaches with next-generation sequencing technologies, including genome-wide association study, whole exome sequencing, and bulk and single-cell RNA sequencing. This review highlights the multifaceted impacts of various findings that have shaped the current molecular and genetic landscape of EoE, providing insights that facilitate further understanding of the disease process.

Pre-treatment differential correlation of gene expression and response to topical steroids in eosinophilic esophagitis

Few predictors of response to topical corticosteroid (tCS) treatment have been identified in eosinophilic esophagitis (EoE). We aimed to determine whether baseline gene expression predicts histologic response to tCS treatment for EoE. We analyzed prospectively collected samples from incident EoE cases who were treated with tCS for 8 weeks in a development cohort (prospective study) or in an independent validation cohort (clinical trial). Whole transcriptome RNA expression was determined from a baseline (pre-treatment) RNA-later preserved esophageal biopsy. Baseline expression was compared between histologic responders (<15 eos/hpf) and non-responders (≥15 eos/hpf), and differential correlation was used to assess baseline gene expression by response status. In 87 EoE cases analyzed in the development set, there were no differentially expressed genes associated with treatment response (at false discovery rate = 0.1). However, differential correlation identified a module of 22 genes with statistically significantly high pairwise correlation in non-responders (mean correlation coefficient = 0.7) compared to low correlation in responders (coefficient = 0.3). When this 22-gene module was applied to the 89 EoE cases in the independent cohort, it was not validated to predict tCS response at the 15 eos/hpf threshold (mean correlation coefficient = 0.32 in responders and 0.25 in nonresponders). Exploration of other thresholds also did not validate any modules. Though we identified a 22 gene differential correlation module measured pre-treatment that was strongly associated with subsequent histologic response to tCS in EoE, this was not validated in an independent population. Alternative methods to predict steroid response should be explored.

Current and emerging immunomodulators for treatment of SARS-CoV2 infection (COVID-19)

INTRODUCTION

SARS-CoV-2, the virus that causes COVID-19, elicits a variety of host responses ranging from asymptomatic or mild illness in most people, to severe disease and critical illness in a subset of patients with systemic inflammation and hypoxemic respiratory failure.

AREAS COVERED

Heterogeneous clinical presentations are often driven by disparate responses of the host immune system, with severe disease associated with aberrant interferon signaling or cytokine storm syndrome. This manuscript examines current therapeutic approaches, including the use of immunomodulators such as corticosteroids, interleukin inhibitors, kinase inhibitors, fluvoxamine, and ivermectin, and also explores the ways that these therapies and others may be used to treat COVID-19 in the future.

EXPERT OPINION

Modulation of the immune response has become a mainstay of treatment of COVID-19, although the optimal mechanism has not yet been defined and there is considerable controversy regarding clinical management. As time progresses, the therapeutic approach to COVID-19 will undoubtedly change, particularly as we learn more about the pathophysiology of SARS-CoV-2 infection.

scGCN is a graph convolutional networks algorithm for knowledge transfer in single cell omics

Single-cell omics is the fastest-growing type of genomics data in the literature and public genomics repositories. Leveraging the growing repository of labeled datasets and transferring labels from existing datasets to newly generated datasets will empower the exploration of single-cell omics data. However, the current label transfer methods have limited performance, largely due to the intrinsic heterogeneity among cell populations and extrinsic differences between datasets. Here, we present a robust graph artificial intelligence model, single-cell Graph Convolutional Network (scGCN), to achieve effective knowledge transfer across disparate datasets. Through benchmarking with other label transfer methods on a total of 30 single cell omics datasets, scGCN consistently demonstrates superior accuracy on leveraging cells from different tissues, platforms, and species, as well as cells profiled at different molecular layers. scGCN is implemented as an integrated workflow as a python software, which is available at https://github.com/QSong-github/scGCN .

Eosinophilic Esophagitis as a Side Effect of Food Oral Immunotherapy

Food allergies (FAs) include a spectrum of immune-mediated serious and potentially life-threatening medical conditions with an overall estimated prevalence ranging from 4% to 8% in the U.S. and Europe. Significant progress in food allergen-specific immunotherapy has been accomplished over the past 10 years. The most studied strategy has been oral immunotherapy (OIT), also known as food desensitization, a treatment in which a child is slowly and deliberately given a small amount of the food to ingest (that previously was a food allergy trigger) with the ultimate goal of the child eating that food without a reaction. OIT is now recommended in the European guidelines for the treatment of milk, egg, and peanut allergies and was the first American Food Drug Administration (FDA) approved product for the prevention of severe reaction to peanuts in 4–17 year olds to be released on the market. The side effects associated with OIT treatment trials are mild to moderate, predominantly oropharyngeal, and easily treated. More severe reactions, such as generalized urticaria/angioedema, wheezing/respiratory distress, laryngeal edema, and repetitive emesis, have been reported. However systemic reactions are very rare. Low-dose immunotherapy is associated with significantly fewer side effects. Currently, its most limiting allergic side effect is that approximately 10–15% of subjects treated with OIT experience gastrointestinal symptoms, preventing the continuation of therapy. Eosinophilic esophagitis (EoE) has also been reported as a cause of persistent abdominal symptoms in OIT.

Clinical and Molecular Factors Associated With Histologic Response to Topical Steroid Treatment in Patients With Eosinophilic Esophagitis

BACKGROUND & AIMS

Few factors have been identified that can be used to predict response of patients with eosinophilic esophagitis (EoE) to topical steroid treatment. We aimed to determine whether baseline clinical, endoscopic, histologic, and molecular features of EoE can be used to predict histologic response.

METHODS

We collected data from 97 patients with EoE, from 2009 through 2015, treated with a topical steroid for 8 weeks; 59 patients had a histologic response to treatment. Baseline clinicopathologic features and gene expression patterns were compared between patients with a histologic response to treatment (<15 eos/hpf) and non-responders (≥15 eos/hpf). We performed sensitivity analyses for alternative histologic response definitions. Multivariate logistic regression was performed to identify predictive factors associated with response to therapy, which were assessed with area under the receiver operator characteristic (AUROC) curves.

RESULTS

Baseline dilation was the only independent predictor of non-response (odds ratio [OR], 0.30; 95% CI, 0.10-0.89). When an alternate response (<1 eos/hpf) and non-response (<50% decrease in baseline eos/hpf) definition was used, independent predictors of response status were age (OR, 1.08; 95% CI, 1.02-1.14), food allergies (OR, 12.95; 95% CI, 2.20-76.15), baseline dilation (OR, 0.17; 95% CI, 0.03-0.88), edema or decreased vascularity (OR, 0.20; 95% CI, 0.04-1.03), and hiatal hernia (OR, 0.07; 95% CI, 0.01-0.66). Using these 5 factors, we developed a predictive model that discriminated complete responders from non-responders with an AUROC of 0.88. Baseline gene expression patterns were not associated with treatment response and did not change with different histologic response thresholds.

CONCLUSIONS

In an analysis of 97 patients with EoE, we found dilation to be the only baseline factor associated with non-response to steroid treatment (<15 eos/hpf). However, a model comprising 5 clinical, endoscopic, and histologic factors identified patients with a complete response (<1 eos/hpf). A baseline gene expression panel was not predictive of treatment response at any threshold.

Molecular basis and cellular mechanisms of eosinophilic esophagitis for the clinical practice

Eosinophilic esophagitis (EoE) is a chronic, allergen-driven inflammatory esophageal disease characterized by predominantly eosinophilic inflammation leading to esophageal dysfunction. Recent efforts to understand EoE have increased our knowledge of the disease. Areas covered: Multiple cells, molecules, and genes interplay with early life environmental factors in the pathophysiology of EoE to converge in the esophageal epithelium at the center of disease pathogenesis. Epithelial cells constitute a mayor cytokine source for TSLP and Calpain-14; an impaired epithelial barrier function allowing penetration of food and microbiota-derived antigens is involved in triggering and maintaining inflammation. Eosinophil and mast cell-derived products, including TGFβ, together with IL-1β and TNFα, promote epithelial mesenchymal transition in EoE, contributing to tissue remodeling by synthetizing and depositing extracellular matrix in subepithelial layers. This article aims to provide a state-of-the-art update on the pathophysiology of EoE applied to clinical practice, and latest research and developments with potential interest to improve the diagnosis and treatment of patients with EoE are revised. Expert commentary: Preliminary approaches have provided promising results toward incorporating minimally invasive methods for patient diagnosis and monitoring in clinical practice. Early diagnosis and optimized therapies will allow for personalized medicine in EoE.

FKBP51 regulates decidualization through Ser473 dephosphorylation of AKT

Defective decidualization of human endometrial stromal cells (ESCs) has recently been highlighted as an underlying cause of implantation failure. FK-506-binding protein 51 (FKBP51) has been shown to participate in the steroid hormone response and the protein kinase B (AKT) regulation process, both of which are important pathways involved in decidualization. The objective of the present study was to investigate the potential effects and mechanisms of FKBP51 in the regulation of ESC decidualization. By performing immunohistochemical staining on an endometrial tissue microarray (TMA) derived from normal females, we found that FKBP51 expression was much higher in the luteal phase than in the follicular phase in ESCs. Primary ESCs were isolated from patients to build an in vitro decidualization model through co-culture with medroxyprogesterone acetate (MPA) and 8-bromoadenosine (cAMP). SC79, a specific AKT activator in various physiological and pathological conditions, and shRNA-FKBP51 were used to examine the roles of AKT and FKBP51 in decidualization. The Western blot and RT-PCR results showed that FKBP51, insulin-like growth factor-binding protein 1 (IGFBP1) and prolactin (PRL) expression increased in ESCs treated with MPA + cAMP; meanwhile, the level of p-Ser473 AKT (p-S473 AKT) decreased and forkhead box protein O1 (FOXO1A) expression increased. Decidualization was inhibited by the AKT activator SC79 and the transfection of FKBP51-shRNA by affecting protein synthesis, cell morphology, cell growth and cell cycle. Furthermore, this inhibition was rescued by FKBP51-cDNA transfection. The results supported that FKBP51 promotes decidualization by reducing the Ser473 phosphorylation levels in AKT.

Synaptopodin is upregulated by IL-13 in eosinophilic esophagitis and regulates esophageal epithelial cell motility and barrier integrity

Eosinophilic esophagitis (EoE) is an allergic inflammatory disease of the esophagus mediated by an IL-13-driven epithelial cell transcriptional program. Herein, we show that the cytoskeletal protein synaptopodin (SYNPO), previously associated with podocytes, is constitutively expressed in esophageal epithelium and induced during allergic inflammation. In addition, we show that the SYNPO gene is transcriptionally and epigenetically regulated by IL-13 in esophageal epithelial cells. SYNPO was expressed in the basal layer of homeostatic esophageal epithelium, colocalized with actin filaments, and expanded into the suprabasal epithelium in EoE patients, where expression was elevated 25-fold compared with control individuals. The expression level of SYNPO in esophageal biopsies correlated with esophageal eosinophil density and was improved following anti-IL-13 treatment in EoE patients. In esophageal epithelial cells, SYNPO gene silencing reduced epithelial motility in a wound healing model, whereas SYNPO overexpression impaired epithelial barrier integrity and reduced esophageal differentiation. Taken together, we demonstrate that SYNPO is induced by IL-13 in vitro and in vivo, is a nonredundant regulator of epithelial cell barrier function and motility, and is likely involved in EoE pathogenesis.

Assessment of Safety, Tolerability, Pharmacokinetics, and Pharmacological Effect of Orally Administered CORT125134: An Adaptive, Double-Blind, Randomized, Placebo-Controlled Phase 1 Clinical Study

CORT125134 is an orally active, high‐affinity, selective antagonist of the glucocorticoid receptor that is being developed for indications that may benefit from the modulation of cortisol activity. This first‐in‐human study was conducted to evaluate the dose‐related safety, tolerability, pharmacokinetics and pharmacological effects of CORT125134 and its active metabolite CORT125201. Eighty‐one healthy male or female subjects received a single dose of 5 to 500 mg CORT125134 or matching placebo across 9 cohorts; 1 cohort received 150 mg CORT125134 after a high‐fat breakfast; and 46 subjects received 50 to 500 mg CORT125134 or matching placebo once daily for up to 14 days across 4 cohorts. CORT125134 was well tolerated at doses up to 250 mg per day for 14 days. CORT125134 was absorbed rapidly and eliminated with a mean half‐life ranging from 11 to 19 hours. Steady state was achieved by day 7. Exposure increased in a greater than proportional manner, particularly at lower doses. Exposure to CORT125201 at steady state was less than 5% that of parent CORT125134. Evidence for the desired pharmacological effect (glucocorticoid receptor antagonism) was demonstrated by the ability of CORT125134 to prevent several effects of the glucocorticoid receptor agonist prednisone.

Esophageal and Small Intestinal Mucosal Integrity in Eosinophilic Esophagitis and Response to an Elemental Diet

OBJECTIVES

The esophageal mucosal integrity is impaired in eosinophilic esophagitis (EoE) and it has been suggested that the duodenal permeability is increased. The absence of food allergens may restore the integrity. The aims of this study were to assess duodenal permeability in EoE and to evaluate the effect of an elemental diet on the esophageal and duodenal integrity.

METHODS

In this prospective study 17 adult EoE patients and 8 healthy controls (HC) were included. Esophageal biopsy specimens were sampled before and after 4 weeks of elemental diet to measure eosinophil counts and gene expression of tight junction and barrier integrity proteins. Esophageal and duodenal impedance were measured by electrical tissue impedance spectroscopy and Ussing chambers were used to measure transepithelial resistance (TER) and transepithelial molecule flux. Small intestinal permeability was measured using a test, measuring lactulose/mannitol (L/M) ratios.

RESULTS

In EoE patients, the esophageal but not the duodenal integrity was impaired, compared with HC. We observed no significant difference between L/M ratios of HC and EoE patients. After diet, eosinophil counts decreased significantly, which was paralleled by normalization of esophageal impedance and transepithelial molecule flux. The esophageal TER improved significantly, but did not reach values seen in HC. Esophageal expression of genes encoding for barrier integrity proteins filaggrin and desmoglein-1 was impaired at baseline and restored after diet.

CONCLUSIONS

An elemental diet restores esophageal integrity, suggesting that it is at least partly secondary to allergen exposure. Duodenal integrity seems not to be affected in EoE, and possibly plays a minor role in its pathophysiology.

Eosinophilic Esophagitis: A Comprehensive Review

Eosinophilic esophagitis (EoE) is an emerging chronic atopic clinical-pathologic disease with an estimated prevalence of 1/1000 similar to the one of Crohn's diseases. Usually, EoE is firstly suspected due to symptoms that are caused by esophageal dysfunction and/or fibrosis. EoE diagnosis is confirmed if the esophageal biopsy shows at least 15 eosinophils per high power field (eos/hpf) as a peak value in one or more of at least four specimens obtained randomly from the esophagus. Most of the patients affected by EoE have other atopic diseases such as allergic rhinitis, asthma, IgE-mediated food allergies, and/or atopic dermatitis. The local inflammation is a T helper type 2 (Th2) flogosis, which most likely is driven by a mixed IgE and non-IgE-mediated reaction to food and/or environmental allergens. Recently published genetic studies showed also that EoE is associated with single nucleotide polymorphism (SNP) on genes which are important in atopic inflammation such as thymic stromal lymphopoietin (TSLP) located close to the Th2 cytokine cluster (IL-4, IL-5, IL-13) on chromosome 5q22. When the EoE diagnosis is made, it is imperative to control the local eosinophilic inflammation not only to give symptomatic relief to the patient but also to prevent complications such as esophageal stricture and food impaction. EoE is treated like many other atopic diseases with a combination of topical steroids and/or food antigen avoidance.

FKBP5 mRNA Expression Is a Biomarker for GR Antagonism

CONTEXT

Endogenous Cushing's syndrome is caused by chronically elevated levels of cortisol. Mifepristone, a glucocorticoid receptor (GR) antagonist, is approved for the treatment of Cushing's syndrome. Currently there is an unmet clinical need for a direct biochemical method for monitoring the immediate effectiveness of mifepristone in patients with Cushing's syndrome. The glucocorticoid induction of FK506-binding protein 5 (FKBP5) expression is rapid and has been shown to be attenuated by GR antagonists in a range of in vitro and in vivo models.

OBJECTIVE

The objective of the study was to develop a quantitative PCR assay for FKBP5 mRNA expression in blood and apply it to measure the inhibition of glucocorticoid-induced FKBP5 expression by GR antagonists in healthy human subjects.

METHODS

Briefly, blood samples were acquired from a phase I study in which healthy human subjects were administered either a single dose of the GR agonist prednisone with and without coadministration of a single oral dose of mifepristone or glucocorticoid receptor antagonist (CORT125134) or multiple daily doses of CORT125134 over 14 days with coadministration of prednisone with the final dose. FKBP5 mRNA levels were analyzed by quantitative PCR in blood samples collected at selected time points.

SETTING

The study was conducted at Quotient Clinical (Nottingham, United Kingdom).

RESULTS

Oral administration of the glucocorticoid prednisone to healthy human subjects resulted in a time-dependent increase of FKBP5 mRNA to peak levels of approximately 12-fold compared with unstimulated levels within 4 hours of steroid administration, followed by a reduction to baseline levels within 24 hours. Furthermore, oral administration of mifepristone or the selective GR antagonist CORT125134 had the desired effect of inhibiting prednisone-mediated activation of GR as seen by a reduction of FKBP5 mRNA levels.

CONCLUSIONS

The inhibition of FKBP5 mRNA expression by a selective GR antagonist is a potential clinical biomarker of GR antagonism.

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

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

JAK-STAT6 Pathway Inhibitors Block Eotaxin-3 Secretion by Epithelial Cells and Fibroblasts from Esophageal Eosinophilia Patients: Promising Agents to Improve Inflammation and Prevent Fibrosis in EoE

BACKGROUND

Although most studies on treatments for eosinophilic esophagitis (EoE) have focused on effects in the epithelium, EoE is a transmural disease. Eosinophils that infiltrate the subepithelial layers of the esophagus lead to fibrosis and the serious complications of EoE, and current therapies have shown minimal effects on this fibrosis. We aimed to elucidate T helper (Th)2 cytokine effects on esophageal fibroblasts and to explore potential fibroblast-targeted therapies for EoE.

METHODS

We established telomerase-immortalized fibroblasts from human esophageal biopsies. We stimulated these esophageal fibroblasts with Th2 cytokines, and examined effects of omeprazole and inhibitors of the Janus kinase (JAK)-signal transducer and activator of transcription (STAT6) pathway (AS1517499, leflunomide, and ruxolitinib) on STAT6 phosphorylation, STAT6 nuclear translocation, and eotaxin-3 expression. We also measured the effects of these inhibitors in esophageal epithelial cells stimulated with Th2 cytokines.

RESULTS

As in esophageal epithelial cells, Th2 cytokines increased STAT6 phosphorylation, STAT6 nuclear translocation, eotaxin-3 transcription and protein secretion in esophageal fibroblasts. Unlike in epithelial cells, however, omeprazole did not inhibit cytokine-stimulated eotaxin-3 expression in fibroblasts. In contrast, JAK-STAT6 pathway inhibitors decreased cytokine-stimulated eotaxin-3 expression in both fibroblasts and epithelial cells.

CONCLUSIONS

Omeprazole does not inhibit Th2 cytokine-stimulated eotaxin-3 expression by esophageal fibroblasts, suggesting that PPIs will have limited impact on subepithelial EoE processes such as fibrosis. JAK-STAT6 pathway inhibitors block Th2 cytokine-stimulated eotaxin-3 expression both in fibroblasts and in epithelial cells, suggesting a potential role for JAK-STAT inhibitors in treating both epithelial inflammation and subepithelial fibrosis in EoE.

Broide DH, Aceves SS. The TGFβ1 Promoter SNP C-509T and Food Sensitization Promote Esophageal Remodeling in Pediatric Eosinophilic Esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic antigen mediated disease associated with substantial esophageal remodeling and fibrosis. The functional TGFβ1 promoter SNP C-509 associates with renal fibrosis and asthma. The effect of TGFβ1 genotype and EoE severity or potential gene-environment interactions have not been previously reported in EoE.

METHODS

Genotype at TGFβ1 C-509T and remodeling was analyzed in 144 subjects with EoE. The severity of remodeling and inflammation was analyzed in the context of IgE sensitization to food antigens and C-509T genotype.

RESULTS

The TGFβ1 promoter C-509 genotypes CC, CT, and TT were 35%, 52%, and 13%, respectively. Sixty-six percent of subjects were sensitized to foods by positive skin prick test (SPT) or serum specific IgE. TT genotype subjects had significantly more TGFβ1 (CC subjects = 1300 per mm2; TT = 2250 per mm2) (p<0.05) and tryptase (CC subjects = 145 per mm2: TT = 307 per mm2) (p<0.05) positive cells and higher epithelial remodeling scores (2.4 vs 3.7, p<0.001) than CC subjects. The differences in TGFβ1 and tryptase positive cells as well as fibrosis were significantly increased when there was concurrent food sensitization. Food sensitization alone did not associate with any parameters of inflammation or remodeling.

CONCLUSIONS

Our data support a gene-environment interaction between food and genotype at C-509 that modulates disease severity in EoE. Since EoE subjects often continue to consume foods to which they are sensitized, these findings may have clinical relevance for disease management.

Molecular, genetic, and cellular bases for treating eosinophilic esophagitis

Eosinophilic esophagitis (EoE) was historically distinguished from gastroesophageal reflux disease on the basis of histology and lack of responsiveness to acid suppressive therapy, but it is now appreciated that esophageal eosinophilia can respond to proton pump inhibitors. Genetic and environmental factors contribute to risk for EoE, particularly early-life events. Disease pathogenesis involves activation of epithelial inflammatory pathways (production of eotaxin-3 [encoded by CCL26]), impaired barrier function (mediated by loss of desmoglein-1), increased production and/or activity of transforming growth factor-β, and induction of allergic inflammation by eosinophils and mast cells. Susceptibility has been associated with variants at 5q22 (TSLP) and 2p23 (CAPN14), indicating roles for allergic sensitization and esophageal specific protease pathways. We propose that EoE is a unique disease characterized by food hypersensitivity; strong hereditability influenced by early-life exposures and esophageal-specific genetic risk variants; and allergic inflammation and that the disease is remitted by disrupting inflammatory and T-helper type 2 cytokine-mediated responses and through dietary elimination therapy.

Risk factors for eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic antigen driven disease, whereby food and/or aeroallergens result in inflammation and luminal narrowing, and the clinical symptoms of dysphagia and food bolus obstruction events (FBOE). Established risk factors are male gender, Caucasian race and atopy. Increased risk amongst family members, and a single nucleotide polymorphism (SNP) in a gene coding thymic stromal lymphopoietin (TSLP) on the pseudoautosomal region of the X and Y chromosomes supports a genetic predisposition. Environmental factors including the timing and nature of food and aeroallergen exposure to the developing immune system may be important, whilst esophageal barrier function integrity and the influence of microbiota are worthy of future research.

Predictors of response to steroid therapy for eosinophilic esophagitis and treatment of steroid-refractory patients

BACKGROUND & AIMS

Eosinophilic esophagitis (EoE) is commonly treated with swallowed (topical) corticosteroids (tCS). However, few factors have been described that predict outcomes of steroid therapy. We aimed to identify factors associated with nonresponse to tCS and report outcomes of second-line treatment for patients with steroid-refractory EoE.

METHODS

We performed a retrospective cohort study by using the University of North Carolina EoE Clinicopathologic Database to identify patients who received tCS for EoE from 2006 through 2013. Demographic, symptom, endoscopic, and histologic data were extracted from medical records. Immunohistochemistry was performed on archived biopsies. Responders and nonresponders to tCS were compared.

RESULTS

Of 221 patients with EoE who received tCS, 71% had endoscopic improvement, 79% had symptomatic improvement, and 57% had histologic response (<15 eosinophils/high-power field). After multivariate logistic regression, esophageal dilation at the baseline examination predicted nonresponse (odds ratio, 2.9; 95% confidence interval, 1.4-6.3), and abdominal pain predicted response (odds ratio for nonresponse, 0.31; 95% confidence interval, 0.12-0.83); no other clinical features were predictive. On the basis of immunohistochemical analysis, higher baseline levels of tryptase (244 vs 157 mast cells/mm(2), P = .04) and eotaxin-3 (2425 vs 239 cells/mm(2), P = .02) were associated with steroid response, but levels of major basic protein were not. Among 27 steroid-refractory patients, a mean of 2 additional therapies were tried; only 48% of the patients eventually responded to any second-line therapy.

CONCLUSIONS

On the basis of a retrospective analysis of a large group of patients with EoE, only 57% have a histologic response to steroid therapy. Baseline esophageal dilation and decreased levels of mast cells and eotaxin-3 predicted which patients would not respond to therapy. Combining clinical factors and immunohistochemistry might therefore be used to direct therapy.

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.

Immunotherapeutic approaches for the treatment of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a clinical pathologic disease characterized by symptoms of esophageal dysfunction and eosinophilia of the esophagus. When the diagnosis is confirmed, it is important to treat the eosinophilic inflammation not only to control the presenting symptoms, but also to prevent acute and chronic complications. The pathogenesis of EoE is most likely a mixed IgE and non-IgE food-mediated reaction, where Th2 cytokines drive esophageal eosinophilia as in other atopic diseases. Hence, it is not surprising that therapy is based on inflammation control, with steroids (oral or topical) and/or food antigen avoidance. However, these treatment options are not specific, reduce the quality of life of patients and have significant side effects, therefore, there is an ongoing effort to design more specific immunotherapies. In this review, we review standard and immunotherapeutic options for EoE treatment, such as anti-IL-5, anti-TNFα, anti-IgE, anti-CRTH, oral allergy desensitization and environmental immunotherapy.

Update on topical steroid therapy for eosinophilic esophagitis

This review aims to summarize evolving evidence on topical steroid (TS) therapy for eosinophilic esophagitis (EoE). Currently, we still use "off-label" TS, originally designed for bronchial or intranasal delivery. Direct oral administration (i.e., oral viscous budesonide) achieves better histological results than the aerosolized swallowed route, due to longer mucosal contact time. High-dose fluticasone (880 μg bid) has recently shown higher cure rates in children and adults. Steroid resistance is present in around 25-40% of patients. Nonetheless, novel steroid formulations specifically designed for EoE have exhibited outstanding preliminary results (cure rates around 100%). Narrow caliber esophagus (<13 mm) might explain persistent dysphagia despite histological remission on TS therapy and endoscopic dilation should be considered. TS are currently considered safe drugs, but we lack long-term safety data. Maintenance anti-inflammatory therapy is recommended in all patients to prevent disease recurrence and esophageal fibrotic remodeling, although this strategy is yet to be defined.

Eosinophilic esophagitis: an autoimmune esophageal disorder

Eosinophilic esophagitis (EoE) represents a chronic, immune/antigen-mediated esophageal inflammatory disease associated with esophageal dysfunction resulting from severe inflammation. The incidence and prevalence of EoE have been increasing in the past decade; however, the reason for this increase is unclear. There is a chronic inflammatory infiltrate that is present in EoE which promotes inflammation, symptoms, and dysfunction. In addition to eosinophils, interleukin (IL)-5 expressing T cells, B cells, eotaxin-3, IL-13, and IgE-bearing mast cells are present in EoE and are thought to contribute to the disease process. Eosinophils are pro-inflammatory and modulate multiple aspects of the immune response. Eosinophils produce a wide range of inflammatory cytokines, chemokines, granulocyte-monocyte colony-stimulating factors, and tumor necrosis factors. Once activated, eosinophils release granule components, which are toxic to a variety of tissues. Transforming growth factor β1 is a pro-fibrotic molecule produced by epithelial and inflammatory cells, is overexpressed in EoE, and plays a role in esophageal remodeling. Fibrous remodeling in EoE could be associated with symptoms of dysphagia and may explain and predict future esophageal strictures and dysmotility. EoE is a complex disease involving multiple activation pathways, a large number of cells, and various inflammatory molecules. It, along with other atopic disease, is becoming increasingly prevalent and has an important genetic load and may represent as an immunological tolerance disorder of the GI tract.

Intravenous anti-IL-13 mAb QAX576 for the treatment of eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis (EoE) is a chronic allergic disease with limited treatment options.

OBJECTIVE

We evaluated QAX576, an mAb against IL-13, in the treatment of patients with EoE.

METHODS

Patients (18-50 years) with proton pump inhibitor-resistant esophageal eosinophilia received intravenous QAX576 (6 mg/kg) or placebo (2:1) at weeks 0, 4, and 8 and were followed for 6 months. The primary end point was the responder rate for a greater than 75% decrease in peak eosinophil counts at week 12. Efficacy was to be declared if the lower 90% confidence limit for the proportion of responders on QAX576 was 35% or greater. Secondary end points included changes in esophageal eosinophil counts, symptoms assessed by questionnaire scores, and quantification of a series of biomarkers.

RESULTS

Twenty-three patients completed the study up to week 12, and 18 continued to the end of the study. For the proximal and distal esophageal biopsies combined, the responder rate was 12.5% (90% confidence limit, 1% to 43%) with placebo, compared to 40.0% (90% confidence limit, 22% to 61%) with QAX576. Although the primary end point was not met, the mean esophageal eosinophil count decreased by 60% with QAX576 versus an increase of 23% with placebo (P = .004), and the decrease was sustained up to 6 months. There was a trend for improved symptoms, particularly dysphagia. QAX576 improved expression of EoE-relevant esophageal transcripts, including eotaxin-3, periostin, and markers of mast cells and barrier function, for up to 6 months after treatment. QAX576 was well tolerated.

CONCLUSIONS

QAX576 significantly improved intraepithelial esophageal eosinophil counts and dysregulated esophageal disease-related transcripts in adults with EoE in a sustained manner.

Dietary elimination therapy is an effective option for adults with eosinophilic esophagitis

BACKGROUND & AIMS

Eosinophilic esophagitis (EoE) is an immune-mediated disorder. Food elimination is an established treatment for children, but data in adults are limited. We aimed to determine the response of adults with EoE to dietary therapy.

METHODS

This was a retrospective cohort study using the University of North Carolina EoE database from 2006 to 2012. Subjects were age 18 and older, had EoE by consensus guidelines, and had undergone dietary therapy either with a targeted elimination diet or a 6-food elimination diet (SFED). Outcomes were symptomatic, endoscopic, and histologic improvement. Demographic, endoscopic, symptomatic, and laboratory predictors of response to dietary therapy were assessed.

RESULTS

Of 31 adults who underwent dietary therapy (mean age, 36 y; 48% male; 90% white; mean baseline eosinophil count, 78 eos/hpf), 22 had a targeted elimination diet and 9 had SFED. Symptoms improved in 71% (68% in targeted, 78% in SFED), and endoscopic appearance improved in 54% (53% in targeted, 56% in SFED). After dietary therapy, the mean eosinophil count decreased to 43 eos/hpf (P = .009). Eleven subjects (39%) responded with fewer than 15 eos/hpf (32% in targeted and 56% in SFED; P = .41). No clinical, endoscopic, or histologic factors predicted response to dietary therapy. Of the 11 responders, 9 underwent food re-introduction to identify trigger(s), and 4 (44%) reacted to dairy, 4 (44%) reacted to eggs, 2 (22%) reacted to wheat, 1 (11%) reacted to shellfish, 1 (11%) reacted to legumes, and 1 (11%) reacted to nuts.

CONCLUSIONS

Dietary elimination is a successful treatment modality for adults with EoE. Further research should emphasize which factors can predict effective dietary therapy.

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.

Efficacy, dose reduction, and resistance to high-dose fluticasone in patients with eosinophilic esophagitis

BACKGROUND & AIMS

We evaluated the efficacy and safety of high-dose swallowed fluticasone propionate (FP) and dose reduction in patients with eosinophilic esophagitis (EoE) and analyzed esophageal transcriptomes to identify mechanisms.

METHODS

We conducted a randomized, multisite, double-blind, placebo-controlled trial of daily 1760 mcg FP in participants age 3-30 years with active EoE. Twenty-eight participants received FP, and 14 participants received placebo. After 3 months, participants given FP who were in complete remission (CR) received 880 mcg FP daily, and participants in the FP or placebo groups who were not in CR continued or started, respectively, 1760 mcg FP daily for 3 additional months. The primary end point was histologic evidence for CR. Secondary end points were partial remission (PR), symptoms, compliance, esophageal gene expression, esophageal eosinophil count, and the relationship between clinical features and FP responsiveness.

RESULTS

After 3 months, 65% of subjects given FP and no subjects given placebo were in CR (P = .0001); 12% of those given FP and 8% of those given placebo were in PR. In the FP group, 73% of subjects remained in CR, and 20% were in PR after the daily dose was reduced by 50%. Extending FP therapy in FP-resistant participants did not induce remission. FP decreased heartburn severity (P = .041). Compliance, age, sex, atopic status, or anthropomorphic features were not associated with response to FP. Gene expression patterns in esophageal tissues of FP responders were similar to those of patients without EoE; there was evidence for heterogeneous steroid signaling in subjects who did not respond to FP and preliminary evidence for transcripts predictive of FP responsiveness.

CONCLUSIONS

Daily administration of a high dose of FP induces histologic remission in 65%-77% of patients with EoE after 3 months. A 50% dose reduction remained effective in 73%-93% of patients who initially responded to FP. Nonresponders had evidence of steroid resistance; histologic and molecular markers may predict resistance. Clinicaltrials.gov number: NCT00426283.

Mucosal cytokine profiles in paediatric eosinophilic oesophagitis: a case-control study

BACKGROUND

Eosinophilic oesophagitis is an inflammatory condition characterized by a dense eosinophilic infiltrate. The migration of eosinophils into the oesophagus is influenced by cytokines such as IL-5, IL-13 and eotaxin-3. The aim of this study was to evaluate changes in the cytokine expression profiles (IL-5, IL-13 and eotaxin-3/CCL26) in children after topical steroid treatment.

METHODS

a prospective case-control study was performed in 23 paediatric patients (age 5-16 years) with a histological diagnosis of eosinophilic oesophagitis. Histological evaluation and cytokine levels assay (IL-5, IL-13 and eotaxin-3/CCL26) in the proximal and distal oesophagus were performed before, and after 8 weeks of topical budesonide. Data were compared with a matched healthy control group.

RESULTS

quantitative expression levels of IL-5, IL-13 and eotaxin-3 were significantly higher in the eosinophilic oesophagitis group both compared to healthy subjects (p<0.0001). A significant reduction of the eosinophil infiltrate as well as of IL-5, IL-13 and eotaxin-3 mucosal profiles was observed after steroid treatment both at the proximal and distal oesophagus (p<0.0001).

CONCLUSIONS

IL-5, IL-13 and eotaxin-3/CCL26 are significantly over-expressed in the oesophageal epithelium of children with eosinophilic oesophagitis. Topical steroid treatment (inhaled and swallowed budesonide) can induce clinical response with partial mucosal remission.

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.

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.

Clinical implications and pathogenesis of esophageal remodeling in eosinophilic esophagitis

In eosinophilic esophagitis (EoE), remodeling changes are manifest histologically in the epithelium and subepithelium where lamina propria fibrosis, expansion of the muscularis propria, and increased vascularity occur. The clinical symptoms and complications of EoE are largely consequences of esophageal remodeling. Available therapies have demonstrated variable ability to reverse existing remodeling changes of the esophagus. Systemic therapies have the potential of addressing subepithelial remodeling. Esophageal dilation remains a useful, adjunctive therapeutic maneuver in symptomatic adults with esophageal stricture. As novel treatments emerge, it is essential that therapeutic end points account for the fundamental contributions of esophageal remodeling to overall disease activity.

Steroids in pediatric eosinophilic esophagitis

Swallowed fluticasone and oral viscous budesonide are effective first-line therapies for eosinophilic esophagitis in children. Side effects are minimal without evidence of Cushing syndrome, as seen in treatment with systemic corticosteroids. New studies on alternative delivery systems and different corticosteroids (eg, ciclesonide) are encouraging. As knowledge of corticosteroids in eosinophilic esophagitis expands, newer questions continue to arise concerning dose, delivery, and choice of corticosteroids; long-term adverse effects; and maintenance therapies.

Molecular diagnosis of eosinophilic esophagitis by gene expression profiling

BACKGROUND & AIMS

Gene expression profiling provides an opportunity for definitive diagnosis but has not yet been well applied to inflammatory diseases. Here we describe an approach for diagnosis of an emerging form of esophagitis, eosinophilic esophagitis (EoE), which is currently diagnosed by histology and clinical symptoms.

METHODS

We developed an EoE diagnostic panel (EDP) comprising a 96-gene quantitative polymerase chain reaction array and an associated dual-algorithm that uses cluster analysis and dimensionality reduction using a cohort of randomly selected esophageal biopsy samples from pediatric patients with EoE (n = 15) or without EoE (non-EoE controls, n = 14) and subsequently vetted the EDP using a separate cohort of 194 pediatric and adult patient samples derived from both fresh or formalin-fixed, paraffin-embedded tissue: active EoE (n = 91), control (non-EoE and EoE remission, n = 57), histologically ambiguous (n = 34), and reflux (n = 12) samples.

RESULTS

The EDP identified adult and pediatric patients with EoE with approximately 96% sensitivity and approximately 98% specificity, and distinguished patients with EoE in remission from controls, as well as identified patients exposed to swallowed glucorticoids. The EDP could be used with formalin-fixed, paraffin-embedded tissue RNA and distinguished patients with EoE from those with reflux esophagitis, identified by pH-impedance testing. Preliminary evidence showed that the EDP could identify patients likely to have disease relapse after treatment.

CONCLUSIONS

We developed a molecular diagnostic test (referred to as the EDP) that identifies patients with esophagitis in a fast, objective, and mechanistic manner, offering an opportunity to improve diagnosis and treatment, and a platform approach for other inflammatory diseases.

The management of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a clinicopathologic, chronic esophageal inflammatory disease resistant to acid suppressive therapy and is associated with variable symptoms indicative of upper gastrointestinal dysfunction. Per current guidelines established by The International Group of Eosinophil Researchers (TIGERS), the diagnosis is made in symptomatic patients after a biopsy that confirms a peak eosinophil level of ≥15 eosinophils/high-powered field (HPF). The esophagus is distinguished by pronounced tissue eosinophilia in which dietary antigens are key inciting factors for disease pathogenesis; EoE being reversed by elimination of triggering food allergens suggests that the disease is mediated in part by allergic sensitization to foods. Moreover, experimental EoE in mice can be induced not only via food exposure but also via aeroallergen exposure. Consistent with an allergic etiology rather than an acid-induced esophagitis, swallowed glucocorticoids are effective for the treatment of EoE. Evaluation by an allergist is a recommended part of the diagnostic workup, especially for management of allergic comorbidities. Clinical practice for the evaluation of patients with EoE mainly relies on prick skin tests due to the ease and validation of these tests in the context of immediate hypersensitivity. However, both atopy patch testing and serum IgE testing have been used in EoE. Herein, we reviewed the basic clinical features of EoE with a focus on the approach to diagnosing causative food allergens and to dietary therapy.

Association of eosinophilic inflammation with FKBP51 expression in sputum cells in asthma

BACKGROUND

Airway eosinophilia is a predictor of steroid responsiveness in steroid-naïve asthma. However, the relationship between airway eosinophilia and the expression of FK506-binding protein 51 (FKBP51), a glucocorticoid receptor co-chaperone that plays a role in steroid insensitivity in asthma, remains unknown.

OBJECTIVE

To evaluate the relationship between eosinophilic inflammation and FKBP51 expression in sputum cells in asthma.

METHODS

The FKBP51 mRNA levels in sputum cells from steroid-naïve patients with asthma (n = 31) and stable asthmatic patients on inhaled corticosteroid (ICS) (n = 28) were cross-sectionally examined using real-time PCR. Associations between FKBP51 levels and clinical indices were analyzed.

RESULTS

In steroid-naïve patients, the FKBP51 levels were negatively correlated with eosinophil proportions in blood (r = -0.52) and sputum (r = -0.57), and exhaled nitric oxide levels (r = -0.42) (all p<0.05). No such associations were observed in patients on ICS. In steroid-naïve patients, improvement in forced expiratory volume in one second after ICS initiation was correlated with baseline eosinophil proportions in blood (r = 0.74) and sputum (r = 0.76) and negatively correlated with FKBP51 levels (r = -0.73) (all p<0.0001) (n = 20). Lastly, the FKBP51 levels were the lowest in steroid-naïve asthmatic patients, followed by mild to moderate persistent asthmatic patients on ICS, and the highest in severe persistent asthmatic patients on ICS (p<0.0001).

CONCLUSIONS

Lower FKBP51 expression in sputum cells may reflect eosinophilic inflammation and glucocorticoid responsiveness in steroid-naïve asthmatic patients.

Targeting eosinophils in allergy, inflammation and beyond

Eosinophils can regulate local immune and inflammatory responses, and their accumulation in the blood and tissue is associated with several inflammatory and infectious diseases. Thus, therapies that target eosinophils may help control diverse diseases, including atopic disorders such as asthma and allergy, as well as diseases that are not primarily associated with eosinophils, such as autoimmunity and malignancy. Eosinophil-targeted therapeutic agents that are aimed at blocking specific steps involved in eosinophil development, migration and activation have recently entered clinical testing and have produced encouraging results and insights into the role of eosinophils. In this Review, we describe recent advances in the development of first-generation eosinophil-targeted therapies and highlight strategies for using personalized medicine to treat eosinophilic disorders.

Cow's milk elimination: a novel dietary approach to treat eosinophilic esophagitis

OBJECTIVES

Cow's-milk protein is one of the food antigens responsible for causing eosinophilic esophageal inflammation in a majority of children. We describe our experience with treating eosinophilic esophagitis (EoE) in children by eliminating only cow's milk from their diets.

METHODS

This retrospective study assessed the short-term clinical and histological response to eliminating cow's-milk protein from the diet of children with EoE. Only patients undergoing a subsequent upper endoscopy to assess their histological response were included in this analysis.

RESULTS

We identified 17 (12 boys and 5 girls) children with EoE who excluded only cow's milk from their diet. Remission was induced in 11 of 17 (65%) patients; within the remission group, 7 (41%) achieved complete histological remission and 4 patients (24%) were in significant histological remission. The mean peak pre- and posttreatment counts for those in remission were 76 ± 40 and 2 ± 4 (P < 0.01), respectively.

CONCLUSIONS

Elimination of cow's milk-induced clinical and histological remission in 65% (95% confidence interval 42%-88%) of children with EoE in whom it was attempted. This approach offers distinct advantages over other dietary treatment approaches for the initial management of children with EoE. The role of eliminating cow's milk alone for the treatment of EoE warrants further prospective study.

Eosinophilic esophagitis: allergic contribution, testing, and management

Both basic science and clinical data indicate a strong role for allergy as a cause of eosinophilic esophagitis. As a result, one of the desired goals of therapy is identification and elimination of food antigens that trigger the allergic inflammatory pathway. Traditional methods for identification of causative food antigens include induction of symptoms with exposure to the antigen, demonstration of serum IgE antibodies against antigens and induction of immediate (IgE) or delayed (Th2) reactions against dermal instillation of antigens. Although some data support the use of these tests in patients with eosinophilic esophagitis, they are limited in this disease. This limitation results from an inability to provoke recognizable symptoms and a lack of concordance between allergies identified in the skin and the blood with the antigens that trigger esophageal disease. As a result, allergy therapy in eosinophilic esophagitis consists of global elimination of food antigens with an elemental diet or exclusion of the most common antigens. As compliance is difficult with these strategies, the mainstay of allergy therapy in eosinophilic esophagitis has become the use of medications that blunt the allergic pathway such as steroids with a future aimed toward more specific inhibitors of this pathway in eosinophilic esophagitis specifically.

Eosinophilic gastrointestinal diseases--clinically diverse and histopathologically confounding

Eosinophilic gastrointestinal diseases are a group of chronic diseases characterized by a range of symptoms caused by eosinophilic inflammation of various parts of the gastrointestinal tract. Other causes for eosinophilia need to be ruled out prior to making the diagnosis of EGIDs. The most common form of EGID is eosinophilic esophagitis (EoE), an antigen-driven disease that afflicts children and adults and has been identified across the world. Histological features include dense eosinophilia of the esophageal mucosa, eosinophil degranulation, eosinophil microabscess formation, and other features of epithelial inflammation including basal zone hyperplasia and rete pege elongation. Treatments include dietary exclusions and topical corticosteroids.

Evolving molecular targets in the treatment of nonmalignant gastrointestinal diseases

Novel treatments for gastrointestinal (GI) diseases are based on molecular targets. Novel pharmacologic and biological agents with greater selectivity and specificity are being developed for a variety of epithelial diseases, including eosinophilic esophagitis (EoE), gastroesophageal reflux disease (GERD), celiac disease, short bowel syndrome (SBS), and inflammatory bowel diseases (IBDs; Crohn's disease and ulcerative colitis). Motility and secretory agents are being developed for gastroparesis, irritable bowel syndrome (IBS), functional constipation, and diarrhea. Here we focus on data from clinical trials involving validated pharmacodynamic or patient response outcomes.

Biomarkers for eosinophilic esophagitis: a review

BACKGROUND

The complex pathophysiology of eosinophilic esophagitis (EoE) provides several candidate biomarkers that could be used to establish diagnosis, assess response to therapy, and document disease recurrence.

OBJECTIVE

To review the literature on various biomarkers of EoE, with respect to their correlation to disease activity and response to treatment.

DATA SOURCES

A literature search was performed using PubMed and OVID with keyword combinations of EoE and various potential biomarkers.

STUDY SELECTIONS

Between 2006 and 2012, 26 studies that investigated the correlation of various tissue and serum biomarkers with EoE were identified.

RESULTS

The markers investigated included eotaxins-1,-2, and -3, interleukin-5 (IL-5), interleukin-13 (IL-13), eosinophil-derived neurotoxin, mast cell markers, absolute eosinophil count, and micro-RNAs. Several studies have shown a positive correlation between eotaxin-3, IL-5, and IL-13 messenger RNA (mRNA) expression in esophageal tissue and disease activity. Eotaxin-3 mRNA staining was found to have 89% sensitivity for diagnosing EoE. Staining for mast cells and their products has also shown promise. More recently, a microRNA signature that can potentially distinguish EoE from non-EoE esophagitis has been identified.

CONCLUSION

The studies are quite heterogeneous with respect to their methodology and the biomarker(s) studied, but most have investigated tissue biomarkers. Eotaxin-3 and IL-13 have emerged as the most promising ones with respect to sensitivity and degree of positive correlation to disease process. Future research on biomarkers for EoE should include longitudinal studies, establishment of normal values, effects of concomitant atopic diseases, age and gender, and validation of methodology of the tests.

Comparative dietary therapy effectiveness in remission of pediatric eosinophilic esophagitis

BACKGROUND

Eosinophilic esophagitis is a chronic, immune-mediated inflammatory disorder that responds to dietary therapy; however, data evaluating the effectiveness of dietary therapeutic strategies are limited.

OBJECTIVE

This study compared the effectiveness of 3 frequently prescribed dietary therapies (elemental, 6-food elimination, and skin prick and atopy patch-directed elimination diets) and assessed the remission predictability of skin tests and their utility in directing dietary planning.

METHODS

A retrospective cohort of proton-pump inhibitor-unresponsive, non-glucocorticoid-treated patients with eosinophilic esophagitis who had 2 consecutive endoscopic biopsy specimens associated with dietary intervention was identified. Biopsy histology and remissions (<15 eosinophils/high-power field) after dietary therapy and food reintroductions were evaluated.

RESULTS

Ninety-eight of 513 patients met the eligibility criteria. Of these 98 patients, 50% (n= 49), 27% (n= 26), and 23% (n= 23) received elemental, 6-food elimination, and directed diets, respectively. Remission occurred in 96%, 81%, and 65% of patients on elemental, 6-food elimination, and directed diets, respectively. The odds of postdiet remission versus nonremission were 5.6-fold higher (P= .05) on elemental versus 6-food elimination diets and 12.5-fold higher (P= .003) on elemental versus directed diets and were not significantly different (P= .22) on 6-food elimination versus directed diets. After 116 single-food reintroductions, the negative predictive value of skin testing for remission was 40% to 67% (milk, 40%; egg, 56%; soy, 64%; and wheat, 67%).

CONCLUSION

All 3 dietary therapies are effective; however, an elemental diet is superior at inducing histologic remission compared with 6-food elimination and skin test-directed diets. Notably, an empiric 6-food elimination diet is as effective as a skin test-directed diet. The negative predictive values of foods most commonly reintroduced in single-food challenges are not sufficient to support the development of dietary advancement plans solely based on skin test results.