Non-epithelial Gene Expression Correlates with Symptom Severity in Adults with Eosinophilic Esophagitis

BACKGROUND

The mechanistic basis of the variable symptomatology seen in eosinophilic esophagitis (EoE) remains poorly understood.

OBJECTIVE

We examined the correlation of a validated, patient-reported outcome (PRO) metric with a broad spectrum of esophageal transcripts to uncover potential symptom pathogenesis.

METHODS

Data were extracted from 146 adults with EoE through the Consortium of Eosinophilic Gastrointestinal Disease Researchers (CEGIR). Patients were subgrouped by esophageal dilation history. We compared a validated PRO metric, the EoE Activity Index (EEsAI), with a set of transcripts expressed in the esophagus of patients with EoE, the EoE Diagnostic Panel (EDP). We utilized single-cell RNA sequencing data to identify the cellular source of EEsAI-related EDP genes and further analyzed patients with mild and severe symptoms.

RESULTS

The EEsAI correlated with the EDP total score, especially in patients without recent esophageal dilation (r = -0.31, P = .003). We identified 14 EDP genes that correlated with EEsAI scores (r ≥ 0.3, P < .05). Of these, 11 were expressed in non-epithelial cells and 3 in epithelial cells; during histologic remission, only 4/11 (36%) non-epithelial versus 3/3 (100%) epithelial genes had decreased expression to <50% of that in active EoE. Fibroblasts expressed 5/11 (45%) non-epithelial EEsAI-associated EDP genes. A subset of non-epithelial (8/11, 73%), but not EoE-representative (0/4, 0%; CCL26, CAPN14, DSG1, SPINK7), genes was upregulated in patients with EoE with the highest versus lowest symptom burden.

CONCLUSION

The correlation of symptoms and non-epithelial esophageal gene expression substantiates that non-epithelial cells (e.g., fibroblasts) likely contribute to symptom severity.

Role of Mast Cells in Eosinophilic Gastrointestinal Diseases

Mast cells play a central role in the pathogenesis of eosinophilic gastrointestinal disorders (EGIDs), including eosinophilic esophagitis. Their interactions with immune and structural cells, involvement in tissue remodeling, and contribution to symptoms make them attractive targets for therapeutic intervention. More is being discovered regarding the intricate interplay of mast cells and eosinophils. Recent studies demonstrating that depletion of eosinophils is insufficient to improve symptoms of EGIDs have raised the question of whether other cells may play a role in symptomatology and pathogenesis of EGIDs.

Detecting Changes in Mast Cell Numbers Versus Activation in Human Disease: A Roadblock for Current Biomarkers?

The pathophysiology of mast cell (MC)-driven disorders is diverse, ranging from localized reactions to systemic disorders caused by abnormal accumulation and activation in multiorgan systems. Prompt and accurate diagnosis is critically important, both for informing treatment and objective assessment of treatment outcomes. As new therapeutics are being developed to deplete MCs or silence them (eg, by engaging inhibitory receptors that block activation), new biomarkers are needed that can distinguish between MC activation versus burden. Serum tryptase is the gold standard for assessing both MC burden and activation; however, commercial tryptase assays have limitations related to timing of release, lack of discernment between inactive (α) and active (β) forms of tryptase, and interpatient variability of baseline levels. Alternative approaches to measuring MC activation include urinary MC mediators, flow cytometry-based assays or gene expression profiling. Additional markers of MC activation are needed for use in clinical diagnostics, to help selection of treatment of MC diseases, and for assessing outcomes of therapy. We review the spectrum of disorders with known or suspected MC contribution, describe the utility and limitations of current MC markers and assays, and discuss the need for new markers that can differentiate between MC activation and burden.

Quantification of Mucosal Mast Cells in the Gastrointestinal Tract: A Primer for Practicing Pathologists

CONTEXT.—

Mast cells are essential components of the immune system and play crucial pathogenetic roles in several digestive diseases, including mastocytic enterocolitis and eosinophilic gastrointestinal disorders. Pathologists have rarely been asked to evaluate the distribution and density of mast cells in gastrointestinal (GI) biopsy specimens. However, such requests are becoming more common because of an increasing awareness of the role of mast cells in functional GI disease and in both esophageal and nonesophageal eosinophilic gastrointestinal disorders.

OBJECTIVE.—

To provide pathologists with tools to incorporate the assessment of mast cells in the evaluation of esophageal, gastric, and intestinal specimens by developing a systematic approach to their evaluation, counting, and reporting.

DESIGN.—

This study consisted of a review of the literature followed by multiple consensus sessions to decide where to count mast cells and what a countable mast cell is.

RESULTS.—

We reviewed 135 papers addressing the content of mast cells in the digestive tract, selected 21 that detailed how cells were counted (microscope lens, area of high-power fields, locations evaluated, type of cells considered as countable), and summarized their data in a table. Then, drawing from both the acceptable literature and our own extensive experience, we reached a tentative consensus on: (1) the normal numbers in the different segments of the GI tract; (2) the morphology of countable mast cells; and (3) the locations and strategies for counting them.

CONCLUSIONS.—

The result is a set of suggestions for reporting mast cell counts, their distribution, and their location in a way clinicians can understand and use for management decisions.

Esophageal Epithelium and Lamina Propria Are Unevenly Involved in Eosinophilic Esophagitis

BACKGROUND & AIMS

The nature of the involvement of esophageal tissue in eosinophilic esophagitis (EoE) is unclear. We estimated the intrabiopsy site agreements of the EoE Histologic Scoring System (EoEHSS) scores for the grade (degree) and stage (extent) of involvement of the esophageal epithelial and lamina propria and examined if the EoE activity status influenced the intrabiopsy site agreement.

METHODS

Demographic, clinical, and EoEHSS scores collected as part of the prospective Outcome Measures for Eosinophilic Gastrointestinal Diseases Across Ages study were analyzed. A weighted Cohen's kappa agreement coefficient (k) was used to calculate the pairwise agreements for proximal:distal, proximal:middle, and middle:distal esophageal biopsy sites, separately for grade and stage scores, for each of the 8 components of EoEHSS. A k > 0.75 was considered uniform involvement. Inactive EoE was defined as fewer than 15 eosinophils per high-powered field.

RESULTS

EoEHSS scores from 1263 esophageal biopsy specimens were analyzed. The k for the stage of involvement of the dilated intercellular spaces across all 3 sites in inactive EoE was consistently greater than 0.75 (range, 0.87-0.99). The k for lamina propria fibrosis was greater than 0.75 across some of the biopsy sites but not across all 3. Otherwise, the k for all other features, for both grade and stage, irrespective of the disease activity status, was 0.75 or less (range, 0.00-0.74).

CONCLUSIONS

Except for the extent of involvement of dilated intercellular spaces in inactive EoE, the remaining epithelial features and lamina propria are involved unevenly across biopsy sites in EoE, irrespective of the disease activity status. This study enhances our understanding of the effects of EoE on esophageal tissue pathology.

Bulk T-cell receptor sequencing confirms clonality in pediatric eosinophilic esophagitis and identifies a food-specific repertoire

BACKGROUND

Eosinophilic esophagitis (EoE) involves a chronic immune-mediated response to dietary antigens. Recent work identifies T-cell clonality in children with EoE, however, it is unknown whether this is true in adults or whether there is a restricted food-specific T-cell repertoire. We sought to confirm T-cell receptor (TCR) clonality in EoE and assess for differences with specific food triggers.

METHODS

Bulk TCR sequencing was performed on mRNA isolated from esophageal biopsies obtained from adults and children with EoE (n = 15) who had food triggers confirmed by endoscopic evaluation. Non-EoE adult and pediatric controls (n = 10) were included. Differences in TCR clonality by disease and treatment status were assessed. Shared and similar V-J-CDR3s were assessed based on specific food triggers.

RESULTS

Active EoE biopsies from children but not adults displayed decreased unique TCRα/β clonotypes and increased relative abundance of TCRs comprising >1% of the total compared to non-EoE controls and paired inactive EoE samples. Among patients in which baseline, post diet elimination, and food trigger reintroduction samples (n = 6) were obtained, we observed ~1% of TCRs were shared only between pre-diet elimination and trigger reintroduction. Patients with a shared EoE trigger (milk) had a greater degree of shared and similar TCRs compared to patients with differing triggers (seafood, wheat, egg, soy).

CONCLUSION

We confirmed relative clonality in children but not adults with active EoE and identified potential food-specific TCRs, particularly for milk-triggered EoE. Further studies are needed to better identify the broad TCR repertoire relevant to food triggers.

Single-cell sequencing of a novel model of neonatal bile duct ligation in mice identifies macrophage heterogeneity in obstructive cholestasis

Macrophages (MΦ) play a role in neonatal etiologies of obstructive cholestasis, however, the role for precise MΦ subsets remains poorly defined. We developed a neonatal murine model of bile duct ligation (BDL) to characterize etiology-specific differences in neonatal cholestatic MΦ polarization. Neonatal BDL surgery was performed on female BALB/c mice at 10 days of life (DOL) with sham laparotomy as controls. Comparison was made to the Rhesus Rotavirus (RRV)-induced murine model of biliary atresia (BA). Evaluation of changes at day 7 after surgery (BDL and sham groups) and murine BA (DOL14) included laboratory data, histology (H&E, anti-CD45 and anti-CK19 staining), flow cytometry of MΦ subsets by MHCII and Ly6c expression, and single cell RNA-sequencing (scRNA-seq) analysis. Neonatal BDL achieved a 90% survival rate; mice had elevated bile acids, bilirubin, and alanine aminotransferase (ALT) versus controls (p < 0.05 for all). Histology demonstrated hepatocellular injury, CD45+ portal infiltrate, and CK19+ bile duct proliferation in neonatal BDL. Comparison to murine BA showed increased ALT in neonatal BDL despite no difference in histology Ishak score. Neonatal BDL had significantly lower MHCII-Ly6c+ MΦ versus murine BA, however, scRNA-seq identified greater etiology-specific MΦ heterogeneity with increased endocytosis in neonatal BDL MΦ versus cellular killing in murine BA MΦ. We generated an innovative murine model of neonatal obstructive cholestasis with low mortality. This model enabled comparison to murine BA to define etiology-specific cholestatic MΦ function. Further comparisons to human data may enable development of immune modulatory therapies to improve patient outcomes.

Reproducibility and Generalizability of the Web-Based Tool to Predict Lamina Propria Fibrosis in Eosinophilic Esophagitis

We investigated reproducibility and generalizability of the recently developed web-based model to predict lamina propria fibrosis (LPF) in esophageal biopsies with inadequate lamina propria (LP) from patients with eosinophilic esophagitis (EoE) using an independent dataset (N = 183). For grade and stage scores of LPF, the area under the curve for predictive model was 0.77 (0.69-0.84) and 0.75 (0.67-0.82), and its accuracy was 78% and 72%, respectively. These model performance metrics were similar to that of the original model. A significant positive correlation was noted between the models' predictive probability and the grade and stage of LPF assessed by a pathologist (grade: r2 = 0.48, P < 0.001; and stage: r2 = 0.39, P < 0.001). These results support the reproducibility and generalizability of the web-based model to predict the presence of LPF in esophageal biopsies with inadequate LP in EoE. Additional studies are warranted to refine the web-based predictive models to provide predictive probability for sub-scores of LPF severity.

Mucosal Microbiota Associated With Eosinophilic Esophagitis and Eosinophilic Gastritis

OBJECTIVE

The aim of the study was to determine the mucosal microbiota associated with eosinophilic esophagitis (EoE) and eosinophilic gastritis (EoG) in a geographically diverse cohort of patients compared to controls.

METHODS

We conducted a prospective study of individuals with eosinophilic gastrointestinal disease (EGID) in the Consortium of Eosinophilic Gastrointestinal Disease Researchers, including pediatric and adult tertiary care centers. Eligible individuals had clinical data, mucosal biopsies, and stool collected. Total bacterial load was determined from mucosal biopsy samples by quantitative polymerase chain reaction (PCR). Community composition was determined by small subunit rRNA gene amplicons.

RESULTS

One hundred thirty-nine mucosal biopsies were evaluated corresponding to 93 EoE, 17 EoG, and 29 control specimens (18 esophageal) from 10 sites across the United States. Dominant community members across disease activity differed significantly. When comparing EoE and EoG with controls, the dominant taxa in individuals with EGIDs was increased ( Streptococcus in esophagus; Prevotella in stomach). Specific taxa were associated with active disease for both EoE ( Streptococcus , Gemella ) and EoG ( Leptotrichia ), although highly individualized communities likely impacted statistical testing. Alpha diversity metrics were similar across groups, but with high variability among individuals. Stool analyses did not correlate with bacterial communities found in mucosal biopsy samples and was similar in patients and controls.

CONCLUSIONS

Dominant community members ( Streptococcus for EoE, Prevotella for EoG) were different in the mucosal biopsies but not stool of individuals with EGIDs compared to controls; taxa associated with EGIDs were highly variable across individuals. Further study is needed to determine if therapeutic interventions contribute to the observed community differences.

Increased fibrosis and microvessel disease in allograft endomyocardial biopsies of children with chronic graft failure due to cardiac allograft vasculopathy

INTRODUCTION

Chronic graft failure (CGF) is the leading cause of mortality in pediatric heart transplant (PHT) patients and has multifactorial pathogenesis including cardiac allograft vasculopathy (CAV). CGF can present with microvessel disease (MVD) and myocardial fibrosis on endomyocardial biopsies (EMB). We investigated if CGF due to moderate- severe (M-S) CAV has histopathologic MVD and fibrosis prior to or at the time of CAV diagnosis.

METHOD

This retrospective case-control study included PHT with CGF secondary to M-S CAV. Control patients had no CAV or CGF. EMBs from CAV (3 sets: at 1-year post-transplant 1yrCAV, pre-CAV, and at the time of CAV diagnosis) and non-CAV cohorts were reviewed to grade the fibrosis and quantify MVD. Histopathologic changes were correlated and compared between CAV/non-CAV groups.

RESULTS

Each group had 8 patients. The median age at transplantation and time since transplant were similar between the two groups (P=.71 and P=.91, respectively). Fibrosis grade was 3.0 for CAV cohort compared to 1.0 for control (P= .003) and MVD score was 2.1 in CAV and 0.5 in non-CAV patients (P=.003). Similar degrees of fibrosis and MVD were present even before any evidence of CAV (1yrCAV fibrosis grade 2.5, pre-CAV fibrosis grade 2; 1yrCAV vs CAV P=.75, pre-CAV vs CAV P=.63; 1yrCAV MVD score 2, pre-CAV MVD score 2; 1yrCAV vs CAV P=1, pre-CAV vs CAV P=.91). The degree of MVD correlated with fibrosis (r=0.63, P<.0001) for all EMBs.

CONCLUSION

Simultaneous myocardial fibrosis and MVD are noted in CGF secondary to M-S CAV, changes that occur before angiographic CAV. EMBs can reveal significant changes in patients with subsequent development of CAV and may be used to modify the follow-up and treatment for these high-risk patients.

RNA-Sequencing Analysis Identifies Etiology Specific Transcriptional Signatures in Neonatal Acute Liver Failure

OBJECTIVE

To assess hepatic transcriptional signatures in infants with gestational alloimmune liver disease (GALD) compared with other etiologies of neonatal acute liver failure (ALF) and older pediatric patients with ALF.

STUDY DESIGN

Neonates with ALF (international normalized ratio ≥2 within 30 days of life) and deceased neonates without liver disease (<30 days of age) with available liver tissue between 2010 and 2021 were identified at Ann & Robert H. Lurie Children's Hospital of Chicago. Clinical information, liver histology, and data from RNA-sequencing analysis was compared between neonates with GALD, non-GALD etiologies of neonatal ALF, and nondiseased neonatal liver.

RESULTS

Quantification of trichrome staining showed an increase in fibrosis in patients with GALD vs those with non-GALD neonatal ALF (P = .012); however, quantification of α-cytokeratin 19-positive ductules did not differ between groups (P = .244). Gene set enrichment analysis of RNA-sequencing data identified the pathways of complement activation, fibrosis, and organogenesis to be upregulated in patients with GALD with ALF. In contrast, patients with non-GALD causes of neonatal ALF had increased gene expression for interferon-driven immune pathways. Individual genes upregulated in GALD included matrix metallopeptidase 7, hepatocyte growth factor, and chemokine ligand 14.

CONCLUSIONS

We have identified distinct pathways that are significantly upregulated in patients with GALD and potential disease-specific diagnostic biomarkers. Future studies will aim to validate these findings and help identify GALD-specific diagnostic biomarkers to improve diagnostic accuracy and reduce GALD-associated patient mortality.

Enhancing diversity, equity, inclusion, and accessibility in eosinophilic gastrointestinal disease research: the consortium for eosinophilic gastrointestinal disease researchers' journey

In response to the social inequities that exist in health care, the NIH-funded Consortium of Eosinophilic Gastrointestinal Disease Researchers (CEGIR) recently formed a diversity committee to examine systemic racism and implicit bias in the care and research of eosinophilic gastrointestinal diseases (EGIDs). Herein, we describe our process, highlighting milestones and issues addressed since the committee's inception, which we hope will inspire other researchers to enhance diversity, equity, inclusion, and accessibility (DEIA) in their fields. Our journey began by establishing mission and vision statements to define the purpose of the committee. Regular discussion of diversity-related topics was incorporated into existing meetings and web-based materials were shared. This was followed by educational initiatives, including establishing a library of relevant publications and a speaker series to address DEIA topics. We then established a research agenda focused on the following actionable items: (1) to define what is known about the demographics of EGIDs by systematic review of population-based studies; (2) to develop a practical tool for reporting participant demographics to reduce bias in EGID literature; (3) to examine health disparities in the care of individuals with eosinophilic esophagitis who present to the emergency department with an esophageal food impaction; (4) to examine how access to a gastroenterologist affects the conclusions of published research examining the prevalence of pediatric eosinophilic esophagitis; and (5) to develop a model for examining the dimensions of diversity, and provide a framework for CEGIR's ongoing projects and data capture. In addition to promoting consciousness of DEIA, this initiative has fostered inclusivity among CEGIR members and will continue to inspire positive changes in EGID care and research.

International Consensus Recommendations for Eosinophilic Gastrointestinal Disease Nomenclature

BACKGROUND & AIMS

Substantial heterogeneity in terminology used for eosinophilic gastrointestinal diseases (EGIDs), particularly the catchall term "eosinophilic gastroenteritis," limits clinical and research advances. We aimed to achieve an international consensus for standardized EGID nomenclature.

METHODS

This consensus process utilized Delphi methodology. An initial naming framework was proposed and refined in iterative fashion, then assessed in a first round of Delphi voting. Results were discussed in 2 consensus meetings, and the framework was updated and reassessed in a second Delphi vote, with a 70% threshold set for agreement.

RESULTS

Of 91 experts participating, 85 (93%) completed the first and 82 (90%) completed the second Delphi surveys. Consensus was reached on all but 2 statements. "EGID" was the preferred umbrella term for disorders of gastrointestinal (GI) tract eosinophilic inflammation in the absence of secondary causes (100% agreement). Involved GI tract segments will be named specifically and use an "Eo" abbreviation convention: eosinophilic gastritis (now abbreviated EoG), eosinophilic enteritis (EoN), and eosinophilic colitis (EoC). The term "eosinophilic gastroenteritis" is no longer preferred as the overall name (96% agreement). When >2 GI tract areas are involved, the name should reflect all of the involved areas.

CONCLUSIONS

This international process resulted in consensus for updated EGID nomenclature for both clinical and research use. EGID will be the umbrella term, rather than "eosinophilic gastroenteritis," and specific naming conventions by location of GI tract involvement are recommended. As more data are developed, this framework can be updated to reflect best practices and the underlying science.

Pre-endoscopy Symptoms and Age, But Not Esophageal Biopsy Number Are Associated With Post-endoscopy Adverse Events

Esophagogastroduodenoscopy (EGD) is a frequently utilized investigative tool in the management of gastrointestinal conditions in children. Biopsies obtained during EGD may pose risk for post-operative adverse events (AEs), and further understanding of risk is imperative to provide informed consent to families and safe patient care. In particular, the impact of biopsy number and location on the development of AEs has not been studied in pediatric patients. We prospectively assessed for AEs by telephone survey 3-7 days after 209 EGDs performed on patients ages 1-21 years over a 1-year period. Demographic, endoscopic, and histologic data were collected. The most common symptoms reported were throat pain (61%), chest pain (26%), and dysphagia (26%). Binary regression models identified age and pre-operative symptoms as factors that influenced the likelihood of post-operative morbidity. Multiple biopsies from 3 different locations of the esophagus did not impact the risk of post-operative AEs.

Esophageal Distensibility Defines Fibrostenotic Severity in Pediatric Eosinophilic Esophagitis

BACKGROUND & AIMS

Identification of fibrosis in pediatric eosinophilic esophagitis (EoE) relies on symptom assessment and endoscopy. Symptoms are highly variable, and early fibrotic remodeling may go undetected on endoscopy yet contribute to esophageal dysfunction. We aimed to assess whether esophageal distensibility has utility in defining fibrostenotic severity in a cohort of pediatric patients with EoE with symptoms of esophageal dysfunction.

METHODS

We analyzed a prospectively recruited a cohort of children ages 9 to 21 years undergoing upper endoscopy and Endoscopic Functional Lumen Imaging Probe (EndoFLIP) for suspected or previously diagnosed EoE. Esophageal distensibility was evaluated by the distensibility index (DI) and esophageal diameter at the distensibility plateau. The association of esophageal distensibility to clinical, endoscopic, and histologic parameters of disease severity was assessed. Receiver operating characteristic analysis was performed to determine the utility of distensibility in defining esophageal rigidity in pediatric EoE.

RESULTS

We identified 59 pediatric patients with EoE undergoing endoscopy and EndoFLIP at a single pediatric tertiary referral center. DI (mm²/mmHg) was significantly lower in patients with fibrotic as compared with inflammatory features on endoscopy (median, 3.3; interquartile range, 2.3-4.4) vs median, 5.5; interquartile range, 4.1-6.0; P = .02) and showed no correlation with eosinophil count. DI <4.5 mm²/mmHg predicted grade 2 rings on endoscopy with area under the curve of 0.81 (P = .0004). DI predicted food impaction in both unadjusted and adjusted models (fully adjusted odds ratio, 1.44; 95% confidence interval, 1.02-2.14; P = .0486).

CONCLUSION

Esophageal distensibility determined by EndoFLIP is a measure of fibrostenotic severity that can be used to clinically phenotype pediatric EoE. We propose parameters of DI <4.5 mm²/mmHg for defining esophageal rigidity in pediatric patients with EoE ages 9 years and older.

Defining the Patchy Landscape of Esophageal Eosinophilia in Children With Eosinophilic Esophagitis

BACKGROUND & AIMS

Eosinophilic esophagitis (EoE) is a patchy disease of the esophagus with significant variability in intraepithelial eosinophilia. Three biopsies each from distal and proximal esophagus are recommended for identification of active EoE. Recent work suggests 3 biopsy sites are more optimal. We sought to evaluate 2-site vs 3-site esophageal biopsy combinations for utility to identify active EoE.

METHODS

We prospectively obtained 3-site esophageal biopsies based on rigorous endoscopic measurements of the proximal, mid, and distal esophagus and gastroesophageal junction. Biopsies were reviewed by a pathologist, and those with at least 15 eosinophils per high-power field were considered active EoE. The sensitivity of one or more sites to identify active EoE was determined, and endoscopic measurements were correlated to height and age.

RESULTS

Five hundred ninety-six endoscopies were performed in 217 patients; of these, 304 endoscopies in 167 patients had active EoE. Among the initial esophagogastroduodenoscopies with active EoE, distal biopsies had greater than 80% sensitivity, whereas mid and proximal biopsies had sensitivity of 65% and 62%, respectively, and distal + proximal biopsies had the highest diagnostic sensitivity for a 2-site combination. Among the 304 endoscopies with active EoE, 9 had focal eosinophilia restricted to the mid esophagus, and 8 were restricted to the proximal esophagus. For patients with multiple endoscopies with active EoE, nearly one fourth had reduced sites with eosinophilia at the second time point. Endoscopic measurements strongly correlated with height and age.

CONCLUSIONS

This study supports endoscopic measurement-guided 3-site biopsies for optimal disease assessment of active EoE in children.

A Single-Food Milk Elimination Diet Is Effective for Treatment of Eosinophilic Esophagitis in Children

BACKGROUND & AIMS

Cow's milk protein (CMP) is the most common trigger of inflammation in children and adults with eosinophilic esophagitis (EoE). We sought to assess the clinical, endoscopic, and histologic efficacy of dietary elimination of all CMP-containing foods in EoE.

METHODS

We performed a prospective observational study in children with EoE treated with the 1-food elimination diet (1FED), excluding all CMP. Children and their caretakers were educated by a registered dietitian regarding dietary elimination of all CMP-containing foods, with substitutions to meet nutritional needs for optimal growth and development, and daily meal planning. Upper endoscopy with biopsies was performed after 8 to 12 weeks of treatment. The primary end point was histologic remission, defined as fewer than 15 eosinophils per high-power field. Secondary end points were symptomatic, endoscopic, and quality-of-life (QOL) improvements.

RESULTS

Forty-one children (76% male; ages, 9 ± 4 years; 88% white) underwent 1FED education and post-treatment endoscopy with biopsies. Histologic remission occurred in 21 (51%) children, with a decrease in peak eosinophils per high-power field from a median of 50 (interquartile range, 35-70) to a median of 1 (interquartile range, 0-6; P < .0001). Endoscopic abnormalities improved in 24 (59%) patients, while symptoms improved in 25 (61%). Improved symptoms included chest pain, dysphagia, and pocketing/spitting out food. Parents perceived worse QOL, while children perceived improved QOL with the 1FED.

CONCLUSIONS

One-food elimination of CMP-containing foods from the diet induced histologic remission in more than 50% of children with EoE and led to significant improvement in symptoms and endoscopic abnormalities. The ease of implementation and adherence supports the 1FED as first-line dietary treatment.

Reliability and responsiveness of endoscopic disease activity assessment in eosinophilic esophagitis

BACKGROUND AND AIMS

Endoscopic outcomes have become important measures of eosinophilic esophagitis (EoE) disease activity, including as an endpoint in randomized controlled trials (RCTs). We evaluated the operating properties of endoscopic measures for use in EoE RCTs.

METHODS

Modified Research and Development/University of California Los Angeles appropriateness methods and a panel of 15 international EoE experts identified endoscopic items and definitions with face validity that were used in a 2-round voting process to define simplified (all items graded as absent or present) and expanded versions (additional grades for edema, furrows, and/or exudates) of the EoE Endoscopic Reference Score (EREFS). Inter- and intrarater reliability of these instruments (expressed as intraclass correlation coefficients [ICC]) were evaluated using paired endoscopy video assessments of 2 blinded central readers in patients before and after 8 weeks of proton pump inhibitors, swallowed topical corticosteroids, or dietary elimination. Responsiveness was measured using the standardized effect size (SES).

RESULTS

The appropriateness of 41 statements relevant to EoE endoscopic activity (endoscopic items, item definitions and grading, and other considerations relevant for endoscopy) was considered. The original and expanded EREFS demonstrated moderate-to-substantial inter-rater reliability (ICCs of .472-.736 and .469-.763, respectively) and moderate-to-almost perfect intrarater reliability (ICCs of .580-.828 and .581-.828, respectively). Strictures were least reliably assessed (ICC, .072-.385). The original EREFS was highly responsive (SES, 1.126 [95% confidence interval {CI}, .757-1.534]), although both expanded versions of EREFS, scored based on worst affected area, were numerically most responsive to treatment (expanded furrows: SES, 1.229 [95% CI, .858-1.643]; all items expanded: SES, 1.252 [95% CI, .880-1.667]). The EREFS and its modifications were not more reliably scored by segment and also not more responsive when proximal and distal EREFSs were summed.

CONCLUSIONS

EREFS and its modifications were reliable and responsive, and the original or expanded versions of the EREFS may be preferred in RCTs. Disease activity scored based on the worst affected area optimizes reliability and responsiveness.

Evaluating Eosinophilic Colitis as a Unique Disease Using Colonic Molecular Profiles: A Multi-Site Study

BACKGROUND & AIMS

Colonic eosinophilia, an enigmatic finding often referred to as eosinophilic colitis (EoC), is a poorly understood condition. Whether EoC is a distinct disease or a colonic manifestation of eosinophilic gastrointestinal diseases (EGIDs) or inflammatory bowel disease (IBD) is undetermined.

METHODS

Subjects with EoC (n = 27) and controls (normal [NL, n = 20], Crohn's disease [CD, n = 14]) were enrolled across sites associated with the Consortium of Eosinophilic Gastrointestinal Disease Researchers. EoC was diagnosed as colonic eosinophilia (ascending ≥100, descending ≥85, sigmoid ≥65 eosinophils/high-power field) with related symptoms. Colon biopsies were subjected to RNA sequencing. Associations between gene expression and histologic features were analyzed with Spearman correlation; operational pathways and cellular constituents were computationally derived.

RESULTS

We identified 987 differentially expressed genes (EoC transcriptome) between EoC and NL (>1.5-fold change, P < .05). Colonic eosinophil count correlated with 31% of EoC transcriptome, most notably with CCL11 and CLC (r = 0.78 and 0.77, P < .0001). Among EoC and other EGIDs, there was minimal transcriptomic overlap and minimal evidence of a strong allergic type 2 immune response in EoC compared with other EGIDs. Decreased cell cycle and increased apoptosis in EoC compared with NL were identified by functional enrichment analysis and immunostaining using Ki-67 and cleaved caspase-3. Pericryptal circumferential eosinophil collars were associated with the EoC transcriptome (P < .001). EoC transcriptome-based scores were reversible with disease remission and differentiated EoC from IBD, even after controlling for colonic eosinophil levels (P < .0001).

CONCLUSIONS

We established EoC transcriptomic profiles, identified mechanistic pathways, and integrated findings with parallel IBD and EGID data. These findings establish EoC as a distinct disease compared with other EGIDs and IBD, thereby providing a basis for improving diagnosis and treatment.

Functional and Phenotypic Characterization of Siglec-6 on Human Mast Cells

Mast cells are tissue-resident cells that contribute to allergic diseases, among others, due to excessive or inappropriate cellular activation and degranulation. Therapeutic approaches to modulate mast cell activation are urgently needed. Siglec-6 is an immunoreceptor tyrosine-based inhibitory motif (ITIM)-bearing receptor selectively expressed by mast cells, making it a promising target for therapeutic intervention. However, the effects of its engagement on mast cells are poorly defined. Siglec-6 expression and endocytosis on primary human mast cells and mast cell lines were assessed by flow cytometry. SIGLEC6 mRNA expression was examined by single-cell RNAseq in esophageal tissue biopsy samples. The ability of Siglec-6 engagement or co-engagement to prevent primary mast cell activation was determined based on assessments of mediator and cytokine secretion and degranulation markers. Siglec-6 was highly expressed by all mast cells examined, and the SIGLEC6 transcript was restricted to mast cells in esophageal biopsy samples. Siglec-6 endocytosis occurred with delayed kinetics relative to the related receptor Siglec-8. Co-crosslinking of Siglec-6 with FcεRIα enhanced the inhibition of mast cell activation and diminished downstream ERK1/2 and p38 phosphorylation. The selective, stable expression and potent inhibitory capacity of Siglec-6 on human mast cells are favorable for its use as a therapeutic target in mast cell-driven diseases.

Loss of Endothelial TSPAN12 Promotes Fibrostenotic Eosinophilic Esophagitis via Endothelial Cell-Fibroblast Crosstalk

BACKGROUND & AIMS

Eosinophilic esophagitis (EoE) can progress to fibrostenosis by unclear mechanisms. Herein, we investigated gene dysregulation in fibrostenotic EoE, its association with clinical parameters and specific pathways, and the functional consequences.

METHODS

Esophageal biopsies from subjects with EoE were collected across 11 Consortium of Eosinophilic Gastrointestinal Disease Researchers sites (n = 311) and 2 independent replication cohorts (n = 83). Inclusion criteria for fibrostenotic EoE were endoscopic rings, stricture, and/or a history of dilation. Endoscopic, histologic, and molecular features were assessed by the EoE Endoscopic Reference Score, EoE Histology Scoring System, EoE Diagnostic Panel, and RNA sequencing. Esophageal endothelial TSPAN12 expression and functional effects on barrier integrity and gene expression were analyzed in vitro.

RESULTS

TSPAN12 was the gene most correlated with fibrostenosis (r = -0.40, P < .001). TSPAN12 was lower in fibrostenotic EoE and correlated with EoE Endoscopic Reference Score, EoE Diagnostic Panel, and EoE Histology Scoring System (r = 0.34-0.47, P < .001). Lower TSPAN12 associated with smaller esophageal diameter (r = 0.44, P = .03), increased lamina propria fibrosis (r = -0.41, P < .001), and genes enriched in cell cycle-related pathways. Interleukin (IL)-13 reduced TSPAN12 expression in endothelial cells. Conversely, anti-IL-13 therapy increased TSPAN12 expression. TSPAN12 gene silencing increased endothelial cell permeability and dysregulated genes associated with extracellular matrix pathways. Endothelial cell-fibroblast crosstalk induced extracellular matrix changes relevant to esophageal remodeling.

CONCLUSIONS

Patients with fibrostenotic EoE express decreased levels of endothelial TSPAN12. We propose that IL-13 decreases TSPAN12, likely contributing to the chronicity of EoE by promoting tissue remodeling through fibroblast-endothelial cell crosstalk.

Development of a core outcome set for therapeutic studies in eosinophilic esophagitis (COREOS)

BACKGROUND

End points used to determine treatment efficacy in eosinophilic esophagitis (EoE) have evolved over time. With multiple novel therapies in development for EoE, harmonization of outcomes measures will facilitate evidence synthesis and appraisal when comparing different treatments.

OBJECTIVE

We sought to develop a core outcome set (COS) for controlled and observational studies of pharmacologic and diet interventions in adult and pediatric patients with EoE.

METHODS

Candidate outcomes were generated from systematic literature reviews and patient engagement interviews and surveys. Consensus was established using an iterative Delphi process, with items voted on using a 9-point Likert scale and with feedback from other participants to allow score refinement. Consensus meetings were held to ratify the outcome domains of importance and the core outcome measures. Stakeholders were recruited internationally and included adult and pediatric gastroenterologists, allergists, dieticians, pathologists, psychologists, researchers, and methodologists.

RESULTS

The COS consists of 4 outcome domains for controlled and observational studies: histopathology, endoscopy, patient-reported symptoms, and EoE-specific quality of life. A total of 69 stakeholders (response rate 95.8%) prioritized 42 outcomes in a 2-round Delphi process, and the final ratification meeting generated consensus on 33 outcome measures. These included measurement of the peak eosinophil count, Eosinophilic Esophagitis Histology Scoring System, Eosinophilic Esophagitis Endoscopic Reference Score, and patient-reported measures of dysphagia and quality of life.

CONCLUSIONS

This interdisciplinary collaboration involving global stakeholders has produced a COS that can be applied to adult and pediatric studies of pharmacologic and diet therapies for EoE and will facilitate meaningful treatment comparisons and improve the quality of data synthesis.

Continued Basal Zone Expansion After Resolution of Eosinophilia in a Child With Eosinophilic Esophagitis on Benralizumab

ABSTRACT

A 20-year-old woman presented with dysphagia at 8 years of age. She underwent esophagogastroduodenoscopy with biopsies (EGD), which was diagnostic of eosinophilic esophagitis. Diet elimination resulted in improvement in symptoms, reduction in eosinophilia, and resolution of basal zone hyperplasia (BZH) on repeat EGD; however, food reintroduction resulted in recurrence of eosinophilia. Subsequently, her pulmonologist started benralizumab, a monoclonal antibody against the interleukin-5 receptor (IL5Rα) on eosinophils, for her asthma. Seven months after starting benralizumab, she underwent EGD for persistent dysphagia, which was notable for resolution of esophageal eosinophilia but demonstrated marked BZH in association with high numbers of CD3+ T cells and tryptase+ mast cells. She transitioned to dupilumab and had resolution of dysphagia. EGD was performed 10 months after starting dupilumab and demonstrated resolution of BZH and mast cell inflammation with significant reduction in T cells. Review of other patients at our center treated with biologics, most commonly dupliumab, reveals varying degrees of BZH in association with mostly CD3+ lymphocyte inflammation. Mast cells and T cells appear to be capable of coordinating mucosal inflammation and symptoms of EoE independent of eosinophilia in a subset of patients.

Noninvasive biomarkers identify eosinophilic esophagitis: A prospective longitudinal study in children

BACKGROUND

Esophageal histology is critical for diagnosis and surveillance of disease activity in eosinophilic esophagitis (EoE). A validated noninvasive biomarker has not been identified. We aimed to determine the utility of blood and urine eosinophil-associated proteins to diagnose EoE and predict esophageal eosinophilia.

METHODS

Blood and urine were collected from children undergoing endoscopy with biopsy. Absolute eosinophil count (AEC), plasma eosinophil-derived neurotoxin (EDN), eosinophil cationic protein (ECP), major basic protein-1 (MBP-1), galectin-10 (CLC/GAL-10), Eotaxin-2 and Eotaxin-3, and urine osteopontin (OPN) and matrix metalloproteinase-9 (MMP-9) were determined. Differences were assessed between EoE and control, and with treatment response. The capacity to predict EoE diagnosis and esophageal eosinophil counts was assessed.

RESULTS

Of 183 specimens were collected from 56 EoE patients and 15 non-EoE controls with symptoms of esophageal dysfunction; 33 EoE patients had paired pre- and post-treatment specimens. Plasma (CLC/GAL-10, ECP, EDN, Eotaxin-3, MBP-1) and urine (OPN) biomarkers were increased in EoE compared to control. A panel comprising CLC/GAL-10, Eotaxin-3, ECP, EDN, MBP-1, and AEC was superior to AEC alone in distinguishing EoE from control. AEC, CLC/GAL-10, ECP, and MBP-1 were significantly decreased in patients with esophageal eosinophil counts <15/hpf in response to treatment. AEC, CLC/GAL-10, ECP, EDN, OPN, and MBP-1 each predicted esophageal eosinophil counts utilizing mixed models controlled for age, gender, treatment, and atopy; AEC combined with MBP-1 best predicted the counts.

CONCLUSIONS

We identified novel panels of eosinophil-associated proteins that along with AEC are superior to AEC alone in distinguishing EoE from controls and predicting esophageal eosinophil counts.

Nailfold Capillaroscopy as a Biomarker in the Evaluation of Pediatric Inflammatory Bowel Disease

BACKGROUND

Noninvasive screening and disease monitoring are an unmet need in pediatric inflammatory bowel disease (IBD). Nailfold capillaroscopy (NFC) is a validated technique for microvascular surveillance in rheumatologic diseases. NFC uses magnified photography to examine nail bed capillaries called end row loops (ERL). We aimed to identify variations in NFC in pediatric IBD patients and their associations with disease activity.

METHODS

Pediatric patients with Crohn's disease (CD) or ulcerative colitis (UC) and healthy controls were recruited. NFC was performed on patients with newly diagnosed IBD prior to initiating therapy, patients with established IBD, and controls. ERLs were quantified along with a 3mm distance on 8 nailfolds. Serum biomarker levels of disease activity and symptoms activity indexes were correlated with average ERL density digits on both hands. Statistics were performed using chi-squared, ANOVA, and linear regression.

RESULTS

Fifty-one IBD patients and 16 controls were recruited. ERL density was significantly decreased in IBD (Control: 19.2 ERL/3mm vs UC: 15.6 ERL/3mm vs CD: 15.4 ERL/3mm; P < .0001). ERL density was lower in UC patients with lower albumin levels (P = .02, r ² = 0.29).The change in ERL density over time predicted the change in pediatric CD activity index among CD patients (P = .048, r ² = 0.58) with treatment.

CONCLUSIONS

Our data demonstrate ERL density is reduced in IBD compared to controls. Lower albumin levels correlated with lower ERL density in UC. In newly diagnosed CD, ERL density increases over time as disease activity improves with therapy. NFC may be a feasible biomarker of disease activity and utilized for monitoring IBD.

Mast Cell and Eosinophil Counts in Gastric and Duodenal Biopsy Specimens From Patients With and Without Eosinophilic Gastroenteritis

BACKGROUND & AIMS

Mast cells are believed to contribute to the development of eosinophilic gastrointestinal disorders (EGIDs). We quantified mast cells and eosinophils in biopsy specimens from patients with EGIDs and without known esophageal or gastrointestinal disease to investigate associations between these cell types and EGID and its features.

METHODS

We conducted a retrospective study of patients with EGID (n = 52) and of children and adults who underwent upper endoscopy and were found to have no evidence of gastrointestinal or systemic conditions (n = 123). We re-reviewed archived gastric and duodenal biopsy specimens to quantify mast cells (by tryptase immunohistochemistry) and eosinophils. We calculated the specificity of cell count thresholds for identification of patients with EGIDs and evaluated the correlation between mast cell and eosinophil counts and clinical and endoscopic features.

RESULTS

In the gastric biopsy specimens from patients without esophageal or gastrointestinal diseases, the mean mast cell count was 18.1 ± 7.2 cells per high-power field (hpf), and the peak mast cell count was 21.9 ± 8.2 cells/hpf. In the duodenal biopsy specimens from patients without esophageal or gastrointestinal diseases, the mean mast cell count was 23.6 ± 8.1 cells/hpf and the peak mast cell count was 28.1 ± 9.3 cells/hpf. The mean and peak eosinophil counts in gastric biopsy specimens from patients without disease were 3.8 ± 3.6 eosinophils/hpf and 5.8 ± 5.0 eosinophils/hpf; the mean and peak eosinophil counts in duodenal biopsy specimens were 14.6 ± 8.9 eosinophils/hpf and 19.5 ± 11.0 eosinophils/hpf. A mean count of 20 eosinophils/hpf in gastric biopsy specimens or 30 eosinophils/hpf in duodenal biopsy specimens identified patients with EGIDs with high specificity. Gastric and duodenal biopsy specimens from patients with EGIDs had significant increases in mean mast cell counts compared with biopsy specimens from patients without EGIDs. There was a correlation between mean mast cell and eosinophil counts in duodenal biopsy specimens (R = 0.47; P = .01). The mean mast cell and eosinophil counts did not correlate with symptoms or endoscopic features of EGIDs.

CONCLUSIONS

We identified thresholds for each cell type that identified patients with EGIDs with 100% specificity. The increased numbers of mast cells and eosinophils in gastric and duodenal tissues from patients with EGIDs supports the concept that these cell types are involved in pathogenesis. However, cell counts are not associated with symptoms or endoscopic features of EGIDs.

Transcriptional profiling of pediatric cholestatic livers identifies three distinct macrophage populations

Background & aims

Limited understanding of the role for specific macrophage subsets in the pathogenesis of cholestatic liver injury is a barrier to advancing medical therapy. Macrophages have previously been implicated in both the mal-adaptive and protective responses in obstructive cholestasis. Recently two macrophage subsets were identified in non-diseased human liver; however, no studies to date fully define the heterogeneous macrophage subsets during the pathogenesis of cholestasis. Here, we aim to further characterize the transcriptional profile of macrophages in pediatric cholestatic liver disease.

Methods

We isolated live hepatic immune cells from patients with biliary atresia (BA), Alagille syndrome (ALGS), and non-cholestatic pediatric liver by fluorescence activated cell sorting. Through single-cell RNA sequencing analysis and immunofluorescence, we characterized cholestatic macrophages. We next compared the transcriptional profile of pediatric cholestatic and non-cholestatic macrophage populations to previously published data on normal adult hepatic macrophages.

Results

We identified 3 distinct macrophage populations across cholestatic liver samples and annotated them as lipid-associated macrophages, monocyte-like macrophages, and adaptive macrophages based on their transcriptional profile. Immunofluorescence of liver tissue using markers for each subset confirmed their presence across BA (n = 6) and ALGS (n = 6) patients. Cholestatic macrophages demonstrated reduced expression of immune regulatory genes as compared to normal hepatic macrophages and were distinct from macrophage populations defined in either healthy adult or pediatric non-cholestatic liver.

Conclusions

We are the first to perform single-cell RNA sequencing on human pediatric cholestatic liver and identified three macrophage subsets with distinct transcriptional signatures from healthy liver macrophages. Further analyses will identify similarities and differences in these macrophage sub-populations across etiologies of cholestatic liver disease. Taken together, these findings may allow for future development of targeted therapeutic strategies to reprogram macrophages to an immune regulatory phenotype and reduce cholestatic liver injury.

Mast Cell Activation in the Systemic Sclerosis Esophagus

Introduction

Previously, we discovered similar esophageal gene expression patterns in patients with systemic sclerosis (SSc) and eosinophilic esophagitis (EoE) where eosinophil/mast cell-targeted therapies are beneficial. Because SSc and EoE patients experience similar esophageal symptoms, we hypothesized that eosinophil/mast cell-directed therapy may potentially benefit SSc patients. Herein, we determine the association between esophageal mast cell quantities, gene expression and clinical parameters in order to identify SSc patients who may benefit from eosinophil/mast cell-directed therapy.

Methods

Esophageal biopsies from SSc patients and healthy participants were stained for tryptase, a mast cell marker, and associations with relevant clinical parameters including 24h esophageal pH testing were assessed. Intra-epithelial mast cell density was quantified by semi-automated microscopy. Microarray data were utilized for functional and gene set enrichment analyses and to identify intrinsic subset (IS) assignment, an SSc molecular classification system that includes inflammatory, proliferative, limited and normal-like subsets.

Results

Esophageal biopsies from 40 SSc patients (39 receiving proton pump inhibition) and eleven healthy participants were studied. Mast cell numbers in both the upper esophagus (r_s = 0.638, p = 0.004) and the entire (upper + lower) esophagus (r_s = 0.562, p = 0.019) significantly correlated with acid exposure time percentage. The inflammatory, fibroproliferative, and normal-like ISs originally defined in skin biopsies were identified in esophageal biopsies. Although esophageal mast cell numbers in SSc patients and healthy participants were similar, gene expression for mast cell-related pathways showed significant upregulation in the inflammatory IS of SSc patients compared to patients classified as proliferative or normal-like.

Discussion

Esophageal mast cell numbers are heterogeneous in SSc patients and may correlate with acid exposure. Patients with inflammatory IS profiles in the esophagus demonstrate more tryptase staining. Mast cell targeted therapy may be a useful therapeutic approach in SSc patients belonging to the inflammatory IS, but additional studies are warranted.

Molecular, endoscopic, histologic, and circulating biomarker-based diagnosis of eosinophilic gastritis: Multi-site study

BACKGROUND

Eosinophilic gastritis (EG) is a clinicopathologic disorder with marked gastric eosinophilia and clinical symptoms. There is an unmet need among patients with EG for more precise diagnostic tools.

OBJECTIVE

We aimed to develop tissue- and blood-based diagnostic platforms for EG.

METHODS

Patients with EG and control subjects without EG were enrolled across 9 Consortium of Eosinophilic Gastrointestinal Disease Researchers-associated sites. An EG Diagnostic Panel (EGDP; gastric transcript subset) and EG blood biomarker panel (protein multiplex array) were analyzed. EGDP₁₈ scores were derived from the expression of 18 highly dysregulated genes, and blood EG scores were derived from dysregulated cytokine/chemokine levels.

RESULTS

Gastric biopsy specimens and blood samples from 185 subjects (patients with EG, n = 74; control subjects without EG, n = 111) were analyzed. The EGDP (1) identified patients with active EG (P < .0001, area under the curve ≥ 0.95), (2) effectively monitored disease activity in longitudinal samples (P = .0078), (3) highly correlated in same-patient samples (antrum vs body, r = 0.85, P < .0001), and (4) inversely correlated with gastric peak eosinophil levels (r = -0.83, P < .0001), periglandular circumferential collars (r = -0.73, P < .0001), and endoscopic nodularity (r = -0.45, P < .0001). For blood-based platforms, eotaxin-3, thymus and activation-regulated chemokine, IL-5, and thymic stromal lymphopoietin levels were significantly increased. Blood EG scores (1) distinguished patients with EG from control subjects without EG (P < .0001, area under the curve ≥ 0.91), (2) correlated with gastric eosinophil levels (plasma: r = 0.72, P = .0002; serum: r = 0.54, P = .0015), and (3) inversely correlated with EGDP₁₈ scores (plasma: r = -0.64, P = .0015; serum: r = -0.46, P = .0084). Plasma eotaxin-3 levels strongly associated with gastric CCL26 expression (r = 0.81, P < .0001).

CONCLUSION

We developed tissue- and blood-based platforms for assessment of EG and uncovered robust associations between specific gastric molecular profiles and histologic and endoscopic features, providing insight and clinical readiness tools for this emerging rare disease.

Cellular Defects in CVID Patients with Chronic Lung Disease in the USIDNET Registry

PURPOSE

Chronic lung disease is the most common cause of morbidity and mortality in patients with common variable immunodeficiency (CVID). While biomarkers exist to predict non-infectious complications, the unique features that define CVID patients with chronic lung disease are not well understood.

METHODS

We analyzed data from CVID patients from the retrospective USIDNET (United States Immunodeficiency Network) patient database. Patients were categorized into 3 phenotypes for comparison: (1) CVID without chronic lung disease, (2) CVID with bronchiectasis only, and (3) CVID with interstitial lung disease (ILD) with or without bronchiectasis. Among these groups, differences were assessed in demographics, comorbidities, infections, treatments, and peripheral blood immune measures. We analyzed 1518 CVID patients which included 1233 (81.2%) without chronic lung disease, 147 (9.7%) with bronchiectasis only, and 138 (9.1%) with interstitial lung disease.

RESULTS

Patients with ILD had lower CD3+ cell counts (P = .001), CD4+ cell counts (P < .05), and CD8+ cell counts (P < .001) compared with patients without lung disease. Additionally, there was significantly more CVID patients with ILD with pneumonia (P < .001), herpes viruses (P = .01) and fungal infections (P < .001) compared with patients with CVID without chronic lung disease.

CONCLUSION

This analysis suggests that patients with chronic lung disease may be more likely to have lower peripheral T cell counts and complications of those defects compared with CVID patients without chronic lung disease.

Oligoclonal immunoglobulin repertoire in biliary remnants of biliary atresia

Biliary atresia (BA) is a neonatal cholestatic liver disease that is the leading cause of pediatric liver transplantation, however, the mechanism of disease remains unknown. There are two major forms of BA: isolated BA (iBA) comprises the majority of cases and is thought to result from an aberrant immune response to an environmental trigger, whereas syndromic BA (BASM) has associated malformations and is thought to arise from a congenital insult. To determine whether B cells in BA biliary remnants are antigen driven, we examined the immunoglobulin (Ig) repertoire of diseased tissue from each BA group. Deep sequencing of the Ig chain DNA was performed on iBA and BASM biliary remnants and lymph nodes obtained from the Childhood Liver Disease Research Network (ChiLDReN) repository. Statistical analysis of the Ig repertoire provided measures of Ig clonality and the Ig phenotype. Our data demonstrate that B cells infiltrate diseased iBA and BASM biliary remnant tissue. The Ig repertoires of iBA and BASM disease groups were oligoclonal supporting a role for an antigen-driven immune response in both sub-types. These findings shift the current understanding of BA and suggest a role for antigen stimulation in early iBA and BASM disease pathogenesis.

Sialic acid-binding immunoglobulin-like lectin (Siglec) 8 in patients with eosinophilic disorders: Receptor expression and targeting using chimeric antibodies

BACKGROUND

Sialic acid-binding immunoglobulin-like lectin (Siglec) 8 is selectively expressed on eosinophils, mast cells, and basophils and, when engaged on eosinophils, can cause cell death.

OBJECTIVE

We sought to characterize surface and soluble Siglec-8 (sSiglec-8) levels in normal donors (NDs) and eosinophilic donors (EOs) and assess the efficacy of anti-Siglec-8 antibodies in inducing eosinophil cell death in vitro.

METHODS

Eosinophil expression of Siglec-8 was assessed by using flow cytometry and quantitative PCR. Serum sSiglec-8 levels were measured by means of ELISA. Induction of eosinophil death by IgG₄ (chimeric 2E2 IgG₄) and afucosylated IgG₁ (chimeric 2E2 IgG₁ [c2E2 IgG₁]) anti-Siglec-8 antibodies was evaluated in vitro by using flow cytometry and in vivo in humanized mice.

RESULTS

Siglec-8 was consistently expressed on eosinophils from NDs and EOs and did not correlate with absolute eosinophil count or disease activity. sSiglec-8 levels were measurable in sera from most donors unrelated to absolute eosinophil counts or Siglec-8 surface expression. c2E2 IgG₁ and chimeric 2E2 IgG₄ were equally effective at inducing cell death (Annexin-V positivity) of purified eosinophils from NDs and EOs after overnight IL-5 priming. In contrast, killing of purified eosinophils without IL-5 was only seen in EOs, and natural killer cell-mediated eosinophil killing was seen only with c2E2 IgG₁. Finally, treatment of humanized mice with anti-Siglec antibody led to robust depletion of IL-5-induced eosinophilia in vivo.

CONCLUSIONS

Siglec-8 is highly expressed on blood eosinophils from EOs and NDs and represents a potential therapeutic target for eosinophilic disorders. Enhanced killing of eosinophils in the presence of IL-5 might lead to increased efficacy in patients with IL-5-driven eosinophilia.

Updated International Consensus Diagnostic Criteria for Eosinophilic Esophagitis: Proceedings of the AGREE Conference

BACKGROUND & AIMS

Over the last decade, clinical experiences and research studies raised concerns regarding use of proton pump inhibitors (PPIs) as part of the diagnostic strategy for eosinophilic esophagitis (EoE). We aimed to clarify the use of PPIs in the evaluation and treatment of children and adults with suspected EoE to develop updated international consensus criteria for EoE diagnosis.

METHODS

A consensus conference was convened to address the issue of PPI use for esophageal eosinophilia using a process consistent with standards described in the Appraisal of Guidelines for Research and Evaluation II. Pediatric and adult physicians and researchers from gastroenterology, allergy, and pathology subspecialties representing 14 countries used online communications, teleconferences, and a face-to-face meeting to review the literature and clinical experiences.

RESULTS

Substantial evidence documented that PPIs reduce esophageal eosinophilia in children, adolescents, and adults, with several mechanisms potentially explaining the treatment effect. Based on these findings, an updated diagnostic algorithm for EoE was developed, with removal of the PPI trial requirement.

CONCLUSIONS

EoE should be diagnosed when there are symptoms of esophageal dysfunction and at least 15 eosinophils per high-power field (or approximately 60 eosinophils per mm²) on esophageal biopsy and after a comprehensive assessment of non-EoE disorders that could cause or potentially contribute to esophageal eosinophilia. The evidence suggests that PPIs are better classified as a treatment for esophageal eosinophilia that may be due to EoE than as a diagnostic criterion, and we have developed updated consensus criteria for EoE that reflect this change.

New developments in patients with eosinophilic gastrointestinal diseases presented at the CEGIR/TIGERS Symposium at the 2018 American Academy of Allergy, Asthma & Immunology Meeting

The Consortium of Eosinophilic Gastrointestinal Diseases and the International Gastrointestinal Eosinophil Researchers organized a day-long symposium at the recent 2018 Annual Meeting of the American Academy of Allergy, Asthma & Immunology, which was coupled for the first time with the World Allergy Organization meeting to create an international platform. The symposium featured experts in many facets of eosinophilic gastrointestinal diseases, including allergy, immunology, gastroenterology, pathology, and nutrition, and was a well-attended event. The basic science, genetics, cellular immunology, and clinical features of the diseases, with a focus on epithelial, eosinophil, and mast cell responses, as well as current and emerging treatment options, were reviewed. Here we briefly review some of the highlights of the material presented at the meeting.

Biological therapies for eosinophilic gastrointestinal diseases

The scientific basis and the clinical application of mAb therapies that target specific immunologic pathways for eosinophilic gastrointestinal diseases are areas of active interest. There is a growing recognition of a subset of patients with eosinophilic esophagitis whose disease does not respond well to topical steroids or elimination diets. In addition, long-term use of corticosteroids presents possible risks that are currently being evaluated. Systemic therapy with a biologic agent offers potential advantages as a global approach that could limit the need for multiple, locally active medical therapies and allergen avoidance. The identification of novel biologic strategies is ongoing, and the recent validation of instruments and outcome measures to assess disease activity has proved essential in demonstrating efficacy. Studies using biologics that target IL-13 pathways in the treatment of eosinophilic esophagitis have demonstrated substantial promise.

Histamine drives severity of innate inflammation via histamine 4 receptor in murine experimental colitis

Ulcerative colitis (UC) patients exhibit elevated histamine, but how histamine exacerbates disease is unclear as targeting histamine 1 receptor (H1R) or H2R is clinically ineffective. We hypothesized that histamine functioned instead through the other colon-expressed histamine receptor, H4R. In humans, UC patient biopsies exhibited increased H4R RNA and protein expression over control tissue, and immunohistochemistry showed that H4R was in proximity to immunopathogenic myeloperoxidase-positive neutrophils. To characterize this association further, we employed both the oxazolone (Ox)- and dextran sulfate sodium (DSS)-induced experimental colitis mouse models and also found upregulated H4R expression. Mast cell (MC)-derived histamine and H4R drove experimental colitis, as H4R^-/- mice had lower symptom scores, neutrophil-recruitment mediators (colonic interleukin-6 (IL-6), CXCL1, CXCL2), and mucosal neutrophil infiltration than wild-type (WT) mice, as did MC-deficient Kit^W-sh/W-sh mice reconstituted with histidine decarboxylase-deficient (HDC^-/-) bone marrow-derived MCs compared with WT-reconstituted mice; adaptive responses remained intact. Furthermore, Rag2^-/- × H4R^-/- mice had reduced survival, exacerbated colitis, and increased bacterial translocation than Rag2^-/- mice, revealing an innate protective antibacterial role for H4R. Taken together, colonic MC-derived histamine initiates granulocyte infiltration into the colonic mucosa through H4R, suggesting alternative therapeutic targets beyond adaptive immunity for UC.

Eosinophilic Esophagitis in Children: Endoscopic Findings at Diagnosis and Post-intervention

PURPOSE OF REVIEW

The goal of this review is to present and summarize studies on endoscopic findings in eosinophilic esophagitis (EoE), at diagnosis and in response to treatment, utilizing rigorous peer-reviewed literature in children wherever possible and to introduce a recently proposed standardized endoscopic evaluation system.

RECENT FINDINGS

Gold standard of diagnosis and assessment of response to therapy in EoE requires multiple endoscopies with biopsies for histology, which allows for observation of the esophageal mucosa. Typical endoscopic findings in patients with EoE include edema, exudate, furrowing, concentric rings, and strictures. Endoscopic findings have been broadly characterized into inflammatory features (edema, exudate, furrowing) and fibro-stenotic features (rings, stricture), in order to better reflect their underlying pathophysiology. Recent studies suggest strong correlations between endoscopic findings, through composite scoring systems, and histology, and therefore may be helpful as part of disease surveillance. The EoE Endoscopic Reference Score (EREFS) classification system was proposed in 2013 as an outcome metric for standardization in reporting endoscopic signs of EoE. Subsequent studies support utility of composite scoring, which utility has similarly been seen in pediatric treatment trials. Endoscopy in children provides insight into the natural history of EoE, with progressively more fibro-stenotic features occurring over time, giving an additional perspective into esophageal remodeling and response to treatment. Recognition of typical endoscopic findings at diagnosis and upon repeat endoscopy has allowed a clinician to monitor visual changes in esophageal mucosal health. Further studies to assess the role of composite scoring in disease management are needed.

Efficacy of a 4-Food Elimination Diet for Children With Eosinophilic Esophagitis

BACKGROUND & AIMS

A 6-food elimination diet induces remission in most children and adults with eosinophilic esophagitis (EoE). The effectiveness of empiric elimination of only 4 foods has not been studied in children. We performed a prospective observational outcome study in children with EoE treated with dietary exclusion of cow's milk, wheat, egg, and soy. The objective was to assess the clinical, endoscopic, and histologic efficacy of this treatment in EoE.

METHODS

We recruited children (1-18 years old, diagnosed per consensus guidelines) from 4 medical centers. Study participants (n = 78) were given a proton pump inhibitor twice daily and underwent a baseline esophagogastroduodenoscopy. Subjects were instructed on dietary exclusion of cow's milk, wheat, egg, and soy. Clinical, endoscopic, and histologic assessments were made after 8 weeks. Responders had single foods reintroduced for 8 weeks, with repeat endoscopy to assess for recurrence of active disease. The primary endpoint was histologic remission (fewer than 15 eosinophils per high-powered field). Secondary endpoints included symptom and endoscopic improvements and identification of foods associated with active histologic disease.

RESULTS

After 8 weeks on 4-food elimination diet, 50 subjects were in histologic remission (64%). The subjects' mean baseline clinical symptoms score was 4.5, which decreased to 2.3 after 8 weeks of 4-food elimination diet (P < .001). The mean endoscopic baseline score was 2.1, which decreased to 1.3 (P < .001). After food reintroduction, the most common food triggers that induced histologic inflammation were cow's milk (85%), egg (35%), wheat (33%), and soy (19%). One food trigger that induced recurrence of esophageal inflammation was identified in 62% of patients and cow's milk-induced EoE was present in 88% of these patients.

CONCLUSIONS

In a prospective study of children with EoE, 8 weeks of 4-food elimination diet induced clinical, endoscopic, and histologic remission in more than 60% of children with EoE. Although less restrictive than 6-food elimination diet, 4-food elimination diet was nearly as effective, and can be recommended as a treatment for children with EoE.

IgE-associated food allergy alters the presentation of paediatric eosinophilic esophagitis

BACKGROUND

Links between food allergens and eosinophilic esophagitis (EoE) have been established, but the interplay between EoE- and IgE-associated immediate hypersensitivity to foods remains unclear.

OBJECTIVE

We sought to determine the prevalence of IgE-associated food allergy at the time of diagnosis of EoE in children and to determine whether differences existed in presentation and disease compared to subjects with EoE alone.

METHODS

Eosinophilic esophagitis patients were stratified based on the diagnosis of IgE-associated immediate hypersensitivity (EoE + IH vs. EoE-IH). Clinical, histologic, pathologic, and endoscopic differences were investigated using a retrospective database.

RESULTS

We found that 29% of the 198 EoE patients in our cohort had EoE + IH. These subjects presented at a younger age than those without IH (6.05 vs. 8.09 years, P = 0.013) and were more likely to have comorbid allergic disease. Surprisingly, the EoE + IH group presented with significantly different clinical symptoms, with increased dysphagia, gagging, cough, and poor appetite compared to their counterparts in the EoE-IH group. Male gender, allergic rhinitis, the presence of dysphagia, and younger age were independently associated with having EoE + IH. Specific IgE levels to common EoE-associated foods were higher in EoE + IH, regardless of eliciting immediate hypersensitivity symptoms. In contrast, IgE levels for specific foods triggering EoE were relatively lower in both the groups than IgE levels for immediate reactions.

CONCLUSIONS AND CLINICAL RELEVANCE

Immediate hypersensitivity is common in children with EoE and identifies a population of EoE patients with distinct clinical characteristics. Our study describes a subtype of EoE in which IgE-mediated food allergy may impact the presentation of paediatric EoE.

Tetraspanin CD151 Is a Negative Regulator of FcεRI-Mediated Mast Cell Activation

Mast cells are critical in the pathogenesis of allergic disease due to the release of preformed and newly synthesized mediators, yet the mechanisms controlling mast cell activation are not well understood. Members of the tetraspanin family are recently emerging as modulators of FcεRI-mediated mast cell activation; however, mechanistic understanding of their function is currently lacking. The tetraspanin CD151 is a poorly understood member of this family and is specifically induced on mouse and human mast cells upon FcεRI aggregation but its functional effects are unknown. In this study, we show that CD151 deficiency significantly exacerbates the IgE-mediated late phase inflammation in a murine model of passive cutaneous anaphylaxis. Ex vivo, FcεRI stimulation of bone marrow-derived mast cells from CD151(-/-) mice resulted in significantly enhanced expression of proinflammatory cytokines IL-4, IL-13, and TNF-α compared with wild-type controls. However, FcεRI-induced mast cell degranulation was unaffected. At the molecular signaling level, CD151 selectively regulated IgE-induced activation of ERK1/2 and PI3K, associated with cytokine production, but had no effect on the phospholipase Cγ1 signaling, associated with degranulation. Collectively, our data indicate that CD151 exerts negative regulation over IgE-induced late phase responses and cytokine production in mast cells.