Insights into the clinical, immunologic, and genetic underpinnings of food allergy.

The last few decades have seen striking changes in the field of food allergy. The prevalence of the disease has risen dramatically in many parts of the globe, and management of the condition has undergone major revision. While delayed introduction of common allergenic foods during infancy was advised for many years, the learning early about peanut allergy (LEAP) trial and other studies led to a major shift in infant feeding practices, with deliberate early introduction of these foods now recommended. Additionally, the Food and Drug Administration approved the first treatment for food allergy in 2020-a peanut oral immunotherapy (OIT) product that likely represents just the beginning of new immunotherapy-based and other treatments for food allergy. Our knowledge of the environmental and genetic factors contributing to the pathogenesis of food allergy has also undergone transformational advances. Here, we will discuss our efforts to improve the clinical care of patients with food allergy and our understanding of the immunological mechanisms contributing to this common disease.

Systematic identification of genotype-dependent enhancer variants in eosinophilic esophagitis.

Eosinophilic esophagitis (EoE) is a rare atopic disorder associated with esophageal dysfunction, including difficulty swallowing, food impaction, and inflammation, that develops in a small subset of people with food allergies. Genome-wide association studies (GWASs) have identified 9 independent EoE risk loci reaching genome-wide significance (p < 5 × 10-8) and 27 additional loci of suggestive significance (5 × 10-8 < p < 1 × 10-5). In the current study, we perform linkage disequilibrium (LD) expansion of these loci to nominate a set of 531 variants that are potentially causal. To systematically interrogate the gene regulatory activity of these variants, we designed a massively parallel reporter assay (MPRA) containing the alleles of each variant within their genomic sequence context cloned into a GFP reporter library. Analysis of reporter gene expression in TE-7, HaCaT, and Jurkat cells revealed cell-type-specific gene regulation. We identify 32 allelic enhancer variants, representing 6 genome-wide significant EoE loci and 7 suggestive EoE loci, that regulate reporter gene expression in a genotype-dependent manner in at least one cellular context. By annotating these variants with expression quantitative trait loci (eQTL) and chromatin looping data in related tissues and cell types, we identify putative target genes affected by genetic variation in individuals with EoE. Transcription factor enrichment analyses reveal possible roles for cell-type-specific regulators, including GATA3. Our approach reduces the large set of EoE-associated variants to a set of 32 with allelic regulatory activity, providing functional insights into the effects of genetic variation in this disease.

Hypoxia-inducible microRNA-155 negatively regulates epithelial barrier in eosinophilic esophagitis by suppressing tight junction claudin-7.

MicroRNA (miRNA)-mediated mRNA regulation directs many homeostatic and pathological processes, but how miRNAs coordinate aberrant esophageal inflammation during eosinophilic esophagitis (EoE) is poorly understood. Here, we report a deregulatory axis where microRNA-155 (miR-155) regulates epithelial barrier dysfunction by selectively constraining tight junction CLDN7 (claudin-7). MiR-155 is elevated in the esophageal epithelium of biopsies from patients with active EoE and in cell culture models. MiR-155 localization using in situ hybridization (ISH) in patient biopsies and intra-epithelial compartmentalization of miR-155 show expression predominantly within the basal epithelia. Epithelial miR-155 activity was evident through diminished target gene expression in 3D organotypic cultures, particularly in relatively undifferentiated basal cell states. Mechanistically, generation of a novel cell line with enhanced epithelial miR-155 stable overexpression induced a functionally deficient epithelial barrier in 3D air-liquid interface epithelial cultures measured by transepithelial electrical resistance (TEER). Histological assessment of 3D esophageal organoid cultures overexpressing miR-155 showed notable dilated intra-epithelial spaces. Unbiased RNA-sequencing analysis and immunofluorescence determined a defect in epithelial barrier tight junctions and revealed a selective reduction in the expression of critical esophageal tight junction molecule, claudin-7. Together, our data reveal a previously unappreciated role for miR-155 in mediating epithelial barrier dysfunction in esophageal inflammation.

A synthesis and subgroup analysis of the eosinophilic esophagitis tissue transcriptome.

BACKGROUND: Eosinophilic esophagitis (EoE) is a chronic immune mediated inflammatory disorder of the esophagus. It is still unknown why children and adults present differently, and there is little evidence about why it is more common in men than women. OBJECTIVE: Our aim was to synthesize published and unpublished esophageal bulk RNA-sequencing (RNA-seq) data to gain novel insights into the pathobiology of EoE and examine the differences in EoE transcriptome by sex and age group. METHODS: Esophageal bulk RNA-seq data from 5 published and 2 unpublished studies resulting in 137 subjects (EoE: N = 76; controls: N = 61) were analyzed. For overall analysis, combined RNA-seq data of patients with EoE were compared with those of controls and subgroup analysis was conducted in patients with EoE by age of the patient (children [<18 years] vs adults [≥18 years]) and sex (female vs male). Gene-set enrichment analysis, ingenuity pathway analysis (IPA), cell-type analysis, immunohistochemistry, and T-cell or B-cell receptor analysis were performed. RESULTS: Overall analysis identified dysregulation of new genes in EoE compared with controls. IPA revealed that EoE is characterized by a mixed inflammatory response compared with controls. Cell-type analysis showed that cell composition varied with age: children had more mast cells, whereas adults had more macrophages. Finally, gene-set enrichment analysis and IPA revealed pathways that were differentially regulated in adults versus children and male versus female patients with EoE. CONCLUSIONS: Using a unique approach to analyze bulk RNA-seq data, we found that EoE is characterized by a mixed inflammatory response, and the EoE transcriptome may be influenced by age and sex. These findings enhance insights into the molecular mechanisms of EoE.

Epithelial overexpression of IL-33 induces eosinophilic esophagitis dependent on IL-13.

BACKGROUND: Eosinophilic esophagitis (EoE) is an increasingly common inflammatory condition of the esophagus; however, the underlying immunologic mechanisms remain poorly understood. The epithelium-derived cytokine IL-33 is associated with type 2 immune responses and elevated in esophageal biopsy specimens from patients with EoE. OBJECTIVE: We hypothesized that overexpression of IL-33 by the esophageal epithelium would promote the immunopathology of EoE. METHODS: We evaluated the functional consequences of esophageal epithelial overexpression of a secreted and active form of IL-33 in a novel transgenic mouse, EoE33. EoE33 mice were analyzed for clinical and immunologic phenotypes. Esophageal contractility was assessed. Epithelial cytokine responses were analyzed in three-dimensional organoids. EoE33 phenotypes were further characterized in ST2-/-, eosinophil-deficient, and IL-13-/- mice. Finally, EoE33 mice were treated with dexamethasone. RESULTS: EoE33 mice displayed ST2-dependent, EoE-like pathology and failed to thrive. Esophageal tissue remodeling and inflammation included basal zone hyperplasia, eosinophilia, mast cells, and TH2 cells. Marked increases in levels of type 2 cytokines, including IL-13, and molecules associated with immune responses and tissue remodeling were observed. Esophageal organoids suggested reactive epithelial changes. Genetic deletion of IL-13 in EoE33 mice abrogated pathologic changes in vivo. EoE33 mice were responsive to steroids. CONCLUSIONS: IL-33 overexpression by the esophageal epithelium generated immunopathology and clinical phenotypes resembling human EoE. IL-33 may play a pivotal role in the etiology of EoE by activating the IL-13 pathway. EoE33 mice are a robust experimental platform for mechanistic investigation and translational discovery.

Development and dysfunction of structural cells in eosinophilic esophagitis.

Eosinophilic esophagitis (EoE) is a disorder characterized by dysfunction and chronic local inflammation of the esophagus. The incidence and prevalence of EoE are increasing worldwide. The mechanisms responsible are poorly understood, and effective treatment options are limited. From the lumen outward, the esophagus comprises stratified squamous epithelium, lamina propria, and muscle. The tissue-specific nature of EoE strongly suggests that structural cells in the esophagus are involved in the EoE diathesis. Epithelial basal cell hyperplasia and dilated intercellular spaces are cardinal features of EoE. Some patients with EoE develop lamina propria fibrosis, strictures, or esophageal muscle dysmotility. Clinical symptoms of EoE are only weakly correlated with peak eosinophil count, implying that other cell types contribute to EoE pathogenesis. Epithelial, endothelial, muscle, and fibroblast cells can each initiate inflammation and repair, regulate tissue resident immune cells, recruit peripheral leukocytes, and tailor adaptive immune cell responses. A better understanding of how structural cells maintain tissue homeostasis, respond to cell-intrinsic and cell-extrinsic stressors, and exacerbate and/or resolve inflammatory responses in the esophagus is needed. This knowledge will facilitate the development of more efficacious treatment strategies for EoE that can restore homeostasis of both hematopoietic and structural elements in the esophagus.

Machine learning-based identification and characterization of mast cells in eosinophilic esophagitis.

BACKGROUND: Eosinophilic esophagitis (EoE) is diagnosed and monitored using esophageal eosinophil levels; however, EoE also exhibits a marked, understudied esophageal mastocytosis. OBJECTIVES: Using machine learning, we localized and characterized esophageal mast cells (MCs) to decipher their potential role in disease pathology. METHODS: Esophageal biopsy samples (EoE, control) were stained for MCs by anti-tryptase and imaged using immunofluorescence; high-resolution whole tissue images were digitally assembled. Machine learning software was trained to identify, enumerate, and characterize MCs, designated Mast Cell-Artificial Intelligence (MC-AI). RESULTS: MC-AI enumerated cell counts with high accuracy. During active EoE, epithelial MCs increased and lamina propria (LP) MCs decreased. In controls and EoE remission patients, papillae had the highest MC density and negatively correlated with epithelial MC density. MC density in the epithelium and papillae correlated with the degree of epithelial eosinophilic inflammation, basal zone hyperplasia, and LP fibrosis. MC-AI detected greater MC degranulation in the epithelium, papillae, and LP in patients with EoE compared with control individuals. MCs were localized further from the basement membrane in active EoE than EoE remission and control individuals but were closer than eosinophils to the basement membrane in active EoE. CONCLUSIONS: Using MC-AI, we identified a distinct population of homeostatic esophageal papillae MCs; during active EoE, this population decreases, undergoes degranulation, negatively correlates with epithelial MC levels, and significantly correlates with distinct histologic features. Overall, MC-AI provides a means to understand the potential involvement of MCs in EoE and other disorders.

Clinical and molecular correlates of the Index of Severity for Eosinophilic Esophagitis.

BACKGROUND: The Index of Severity for Eosinophilic Esophagitis (I-SEE) is a new expert-defined clinical tool that classifies disease severity of eosinophilic esophagitis (EoE). OBJECTIVE: We aimed to determine whether I-SEE is associated with patient characteristics, molecular features of EoE, or both. METHODS: We analyzed a prospective cohort of patients with EoE from the Consortium of Eosinophilic Gastrointestinal Disease Researchers (CEGIR). Associations between I-SEE and clinical and molecular features (assessed by an EoE diagnostic panel [EDP]) were assessed. RESULTS: In 318 patients with chronic EoE (209 adults, 109 children), median total I-SEE score was 7.0, with a higher symptoms and complications score in children than adults (4.0 vs 1.0; P < .001) and higher inflammatory and fibrostenotic features scores in adults than children (3.0 vs 1.0 and 3.0 vs 0, respectively; both P < .001). Total I-SEE score had a bimodal distribution with the inactive to moderate categories and severe category. EDP score correlated with total I-SEE score (r = -0.352, P < .001) and both inflammatory and fibrostenotic features scores (r = -0.665, P < .001; r = -0.446, P < .001, respectively), but not with symptoms and complications scores (r = 0.047, P = .408). Molecular severity increased from inactive to mild and moderate, but not severe, categories. Longitudinal changes of modified I-SEE scores and inflammatory and fibrostenotic features scores reflected histologic and molecular activity. CONCLUSIONS: I-SEE score is associated with select clinical features across severity categories and with EoE molecular features for nonsevere categories, warranting further validation.

Transcriptomic profiling of the acute mucosal response to local food injections in adults with eosinophilic esophagitis.

BACKGROUND: Exposure of the esophageal mucosa to food allergens can cause acute mucosal responses in patients with eosinophilic esophagitis (EoE), but the underlying local immune mechanisms driving these acute responses are not well understood. OBJECTIVE: We sought to gain insight into the early transcriptomic changes that occur during an acute mucosal response to food allergens in EoE. METHODS: Bulk RNA sequencing was performed on esophageal biopsy specimens from adult patients with EoE (n = 5) collected before and 20 minutes after intramucosal injection of various food extracts in the esophagus. Baseline biopsy specimens from control subjects without EoE (n = 5) were also included. RESULTS: At baseline, the transcriptome of the patients with EoE showed increased expression of genes related to an EoE signature. After local food injection, we identified 40 genes with a potential role in the early immune response to food allergens (most notably CEBPB, IL1B, TNFSF18, PHLDA2, and SLC15A3). These 40 genes were enriched in processes related to immune activation, such as the acute-phase response, cellular responses to external stimuli, and cell population proliferation. TNFSF18 (also called GITRL), a member of the TNF superfamily that is best studied for its costimulatory effect on T cells, was the most dysregulated early EoE gene, showing a 12-fold increase compared with baseline and an 18-fold increase compared with a negative visual response. Further experiments showed that the esophageal epithelium may be an important source of TNFSF18 in EoE, which was rapidly induced by costimulating esophageal epithelial cells with the EoE-relevant cytokines IL-13 and TNF-α. CONCLUSIONS: Our data provide unprecedented insight into the transcriptomic changes that mediate the acute mucosal immune response to food allergens in EoE and suggest that TNFSF18 may be an important effector molecule in this response.

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.

Triggers for eosinophilic esophagitis (EoE): The intersection of food allergy and EoE.

Eosinophilic esophagitis and IgE-mediated food allergy are both food-triggered diseases that are increasing in prevalence. They share many clinical links, including significant comorbidity and similar food triggers, and as atopic diseases, they likely share upstream mechanisms related to barrier function and signals leading to TH2 skewing. In this review, we focus on links between eosinophilic esophagitis and IgE-mediated food allergy with an emphasis on what insights may be derived from overlapping food triggers and immune phenotypes. Through further investigation of these connections, we may be able to better understand not only IgE-mediated food allergy and eosinophilic esophagitis but also general atopic response to food proteins and evolution of allergic response to food.

Common and disparate clinical presentations and mechanisms in different eosinophilic gastrointestinal diseases.

Eosinophilic gastrointestinal diseases (EGIDs) are a group of diseases characterized by selective eosinophil infiltration of the gastrointestinal (GI) tract in the absence of other causes of eosinophilia. These diseases are generally driven by type 2 inflammation, often in response to food allergen exposure. Among all EGIDs, the clinical presentation often includes a history of atopic disease with a variety of GI symptoms. EGIDs are traditionally separated into eosinophilic esophagitis (EoE) and non-EoE EGIDs. EoE is relatively better understood and now associated with clinical guidelines and 2 US Food and Drug Administration-approved treatments, whereas non-EoE EGIDs are rarer and less well-understood diseases without US Food and Drug Administration-approved treatments. Non-EoE EGIDs are further subclassified by the area of the GI tract that is involved; they comprise eosinophilic gastritis, eosinophilic enteritis (including eosinophilic duodenitis), and eosinophilic colitis. As with other GI disorders, the disease presentations and mechanisms differ depending on the involved segment of the GI tract; however, the differences between EoE and non-EoE EGIDs extend beyond which GI tract segment is involved. The aim of this article is to summarize the commonalities and differences between the clinical presentations and disease mechanisms for EoE and non-EoE EGIDs.

Monitoring and modulating the trajectory of eosinophilic esophagitis.

Current treatments of eosinophilic esophagitis (EoE) aim to eliminate esophageal mucosal inflammation and attenuate, stabilize, or reverse stricture formation. However, our ability to study the long-term course of esophageal strictures in patients with EoE is hampered by the short-term existence of this disease. It is unclear to what degree of control of inflammation is needed to prevent stricture formation. Additionally, identified phenotypes of EoE may ultimately dictate different levels of concern and time intervals for developing fibrosis. Currently, multiple methods are used to monitor patients' disease progression to fibrosis, as symptoms alone do not correlate with disease activity. Endoscopic findings and mucosal histology are used to monitor disease activity, but these focus on improvements in inflammation with inconsistent evaluation of underlying fibrosis. The use of functional lumen impedance planimetry, barium esophagraphy, and endoscopic ultrasound continues to expand in EoE. The rapid advancements in EoE have led to an armamentarium of measuring tools and therapies that holistically characterize disease severity and response to therapy. Nevertheless, our ability to evaluate gross esophageal fibrosis and stricture formation from a transmural rather than mucosal view should be a focus of future investigations because it is essential to monitoring and modulating the trajectory of EoE.

Neuroimmune interplay during type 2 inflammation: Symptoms, mechanisms, and therapeutic targets in atopic diseases.

Type 2 inflammation is characterized by overexpression and heightened activity of type 2 cytokines, mediators, and cells that drive neuroimmune activation and sensitization to previously subthreshold stimuli. The consequences of altered neuroimmune activity differ by tissue type and disease; they include skin inflammation, sensitization to pruritogens, and itch amplification in atopic dermatitis and prurigo nodularis; airway inflammation and/or hyperresponsiveness, loss of expiratory volume, airflow obstruction and increased mucus production in asthma; loss of sense of smell in chronic rhinosinusitis with nasal polyps; and dysphagia in eosinophilic esophagitis. We describe the neuroimmune interactions that underlie the various sensory and autonomic pathologies in type 2 inflammatory diseases and present recent advances in targeted treatment approaches to reduce type 2 inflammation and its associated symptoms in these diseases. Further research is needed to better understand the neuroimmune mechanisms that underlie chronic, sustained inflammation and its related sensory pathologies in diseases associated with type 2 inflammation.

Single-cell RNA-sequencing of human eosinophils in allergic inflammation in the esophagus.

BACKGROUND: Eosinophils are elusive cells involved in allergic inflammation. Single-cell RNA-sequencing (scRNA-seq) is an emerging approach to deeply characterize cellular properties, heterogeneity, and functionality. OBJECTIVES: We sought to comprehensively characterize the transcriptome and biological functions of human eosinophils at a site of severe allergic inflammation in the esophagus (ie, eosinophilic esophagitis [EoE]). METHODS: We employed a gravity-based scRNA-seq methodology to sequence blood eosinophils from patients with EoE and control individuals compared to a reanalyzed public scRNA-seq dataset of human esophageal eosinophils of EoE patients. We used flow cytometry, immunostaining, and a stimulation assay to verify mRNA findings. RESULTS: In total, scRNA-seq was obtained from 586 eosinophils (188 from blood [n = 6 individuals] and 398 from esophagus [n = 6 individuals]). The esophageal eosinophils were composed of a population of activated eosinophils (enriched in 659 genes compared with peripheral blood-associated eosinophils) and a small population of eosinophils resembling peripheral blood eosinophils (enriched in 62 genes compared with esophageal eosinophils). Esophageal eosinophils expressed genes involved in sensing and responding to diverse stimuli, most notably IFN-γ, IL-10, histamine and leukotrienes, and succinate. Esophageal eosinophils were most distinguished from other esophageal populations by gene expression of the receptors CCR3, HRH4, SUCNR1, and VSTM1; transcription factors CEBPE, OLIG1, and OLIG2; protease PRSS33; and the hallmark eosinophil gene CLC. A web of bidirectional eosinophil interactions with other esophageal populations was derived. Comparing esophageal eosinophils and mast cells revealed that esophageal eosinophils expressed genes involved in DNAX-activation protein-12 (also known as TYROBP) interactions, IgG receptor-triggered events, immunoregulation, and IL-10 signaling. CONCLUSIONS: In EoE, esophageal eosinophils exist as 2 populations, a minority population resembling blood eosinophils and the other population characterized by high de novo transcription of diverse sensing receptors and inflammatory mediators readying them to potentially intersect with diverse cell types.

Prevalence and Costs of Esophageal Strictures in the United States.

BACKGROUND & AIMS: Esophageal strictures are a leading cause of dysphagia, but data regarding the epidemiology of esophageal strictures are limited. This study aimed to investigate the prevalence, health care utilization, and financial burden of esophageal strictures in the United States. METHODS: We performed a retrospective cohort study using 2 large national insurance claims databases (MarketScan and Medicare). Using International Classification of Diseases-9 and -10 diagnostic codes, annual prevalence was calculated for both cohorts overall, and stratified by age and sex strata. Most common diagnostic and procedural codes associated with esophageal strictures were extracted and analyzed to estimate health care utilization. Direct annual medical costs of esophageal strictures were calculated. RESULTS: The annual prevalence of esophageal strictures in MarketScan in 2021 was 203.14 cases/100,000 people, whereas the annual prevalence in Medicare cohort in 2017 was 1123.47 cases/100,000. Although rates were relatively stable over time, esophageal stricture prevalence increased with advancing age. No prevalence differences were noticed between males and females. Gastroesophageal reflux disease/erosive esophagitis was the top diagnostic code associated with esophageal strictures, although an increase in the proportion of eosinophilic esophagitis codes was noted over time. Esophageal dilation codes were present in ∼50% of stricture cases. The total health care costs associated with esophageal strictures were estimated at $1.39 billion in 2017. CONCLUSIONS: Esophageal strictures are common, affecting between 1/100 and 1/1000 patients in the United States, with the highest rates seen in patients aged 75 years and older. Accordingly, strictures have a significant financial burden on the health care system, with costs greater than $1 billion annually.

Epidemiology and Risk Factors of Eosinophilic Esophagitis in Japan: A Population-Based Study.

BACKGROUND & AIMS: Eosinophilic esophagitis (EoE) has been increasingly diagnosed globally. However, there have been few general population-based studies in Asia. The aim of this study was to investigate EoE epidemiology in the Japanese general population. METHODS: We analyzed an employer-based health insurance claim database from January 2005 to September 2022. EoE cases were identified on the basis of the International Statistical Classification of Diseases and Health-related Problems, 10th Revision code, K20.0. We calculated the incidence and prevalence of EoE using Poisson regression and binomial distribution, respectively. Using 10 matched controls for each EoE case, a nested case-control study was performed to identify potential risk factors for EoE. RESULTS: Of 15,200,895 individuals, 1010 EoE cases were identified. The incidence and prevalence of EoE were 2.82 (95% confidence interval [CI], 2.44-3.26) per 100,000 person-years and 10.68 (95% CI, 10.01-11.37) per 100,000 people in 2022, nearly 3 and 8 times as high as those in 2017, respectively. Smoking was associated with decreased risk of EoE (odds ratio [OR], 0.45, 0.36-0.56, P < .001), whereas alcohol consumption (OR, 1.51, 1.21-1.88, P < .001) was associated with increased risk of EoE along with several allergic conditions and psychiatric disorders. EoE was not related to either body mass index or lifestyle-related diseases such as hypertension, diabetes mellitus, hyperuricemia, and dyslipidemia. CONCLUSIONS: The incidence and prevalence of EoE in Japan have steadily increased over the past 2 decades. Nevertheless, EoE remains less common in Japan compared with the United States and Western Europe. Factors contributing to the epidemiology of EoE on a global basis may improve our understanding of the contribution of genetic and environmental risk factors.

Achalasia is Strongly Associated With Eosinophilic Esophagitis and Other Allergic Disorders.

BACKGROUND & AIMS: Achalasia has been assumed to be an autoimmune disease targeting esophageal myenteric neurons. Recently, we proposed an alternative hypothesis that achalasia sometimes might be allergy-driven, caused by a form of eosinophilic esophagitis (EoE) in which activated eosinophils and/or mast cells infiltrating esophageal muscle release products that disrupt motility and damage myenteric neurons. To seek epidemiologic support for this hypothesis, we identified patients with achalasia in the Utah Population Database, and explored their frequency of having EoE and other allergic disorders. METHODS: We used International Classification of Diseases codes to identify patients with achalasia and allergic disorders including EoE, asthma, atopic dermatitis, contact dermatitis, allergic rhinitis, allergic conjunctivitis, hives/urticaria, and anaphylaxis. We calculated relative risk (RR) for each allergic disorder by comparing the number observed in patients with achalasia with the expected number in individuals matched for birthyear and sex, and we performed subanalyses for patients age ≤40 versus age >40 years. RESULTS: Among 844 patients with achalasia identified (55% female; median age at diagnosis, 58 years), 402 (47.6%) had ≥1 allergic disorder. Fifty-five patients with achalasia (6.5%) had EoE (1.67 EoE cases expected), for a RR of 32.9 (95% confidence interval, 24.8-42.8; P < .001). In 208 patients with achalasia age ≤40 years, the RR for EoE was 69.6 (95% confidence interval, 46.6-100.0; P < .001). RR also was increased significantly for all other allergic disorders evaluated (all greater than 3-fold higher than population rates). CONCLUSIONS: Achalasia is strongly associated with EoE and other allergic disorders. These data support the hypothesis that achalasia sometimes might have an allergic etiology.

Investigating immune profile by CyTOF in patients with Eosinophilic Esophagitis after treatment with orodispersible budesonide.

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

Children with eosinophilic esophagitis non-responsive to combination therapy have distinct esophageal transcriptomic and microbiome profile.

BACKGROUND: A combination of proton-pump inhibitors (PPI) and topical steroids (TS) is used to treat children with eosinophilic esophagitis (EoE). However, a subset of children do not respond to this combination therapy. We aimed to identify the esophageal transcriptional, cell composition, and microbial differences between the non-responders (EoE-PPI-TSnr; n = 7) and responders (EoE-PPI-TSr; n = 7) to the combination therapy for EoE and controls (n = 9) using metatranscriptomics. METHODS: Differential gene expression analysis was used to identify transcriptional differences, validated using the EoE diagnostic panel (EDP). Deconvolution analysis was performed to identify differences in their cell type composition. Microbiome analysis was conducted from esophageal biopsies RNAseq data, and microbial abundance was correlated with esophageal gene expression. RESULTS: In all, 3164 upregulated and 3154 downregulated genes distinguished EoE-PPI-TSnr from EoE-PPI-TSr. Eosinophilic inflammatory response, cytokine signaling, and collagen formation pathways were significantly upregulated in EoE-PPI-TSnr. There was a 56% overlap in dysregulated genes between EoE-PPI-TSnr and EDP, with a perfect agreement in the directionality of modulation. Eosinophils, dendritic cells (DCs), immature DCs, megakaryocytic-erythroid progenitors, and T helper type 1 cells were significantly higher in EoE-PPI-TSnr. There was no significant difference in microbiome diversity. The relative abundance of Fusobacterium sp. and Acinetobacter sp. notably differed in EoE-PPI-TSnr and correlated with the key pathways. CONCLUSION: Our results provide critical insights into the molecular, cellular, and microbial factors associated with the lack of response to PPI and TS combination therapy in children with EoE. This study advances our understanding of the pathobiology of EoE while guiding personalized treatment strategies.