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 and/or molecular features of EoE. 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 (EoE Diagnostic Panel [EDP]) were assessed. RESULTS: In 318 patients with chronic EoE (adults 209, children 109), the 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. 0.0, 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 the histologic and molecular activity. CONCLUSIONS: I-SEE associated with select clinical features across severity categories and with EoE molecular features for non-severe categories, warranting further validation.

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 (ß) 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.

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.

Diversity in Eosinophilic Gastrointestinal Disease Research To address systemic bias in patient care and research in eosinophilic gastrointestinal diseases, the Consortium of Eosinophilic Gastrointestinal Disease Researchers (CEGIR) recently formed a diversity committee. The CEGIR diversity committee has defined its purpose through mission and vision statements and developed structured educational and research initiatives to enhance diversity, equity, inclusivity, and accessibility (DEIA) in all CEGIR activities. Here, we share the process of formation of our diversity committee, highlighting milestones achieved and summarizing future directions. We hope that this report will serve as a guide and an inspiration for other researchers to enhance DEIA in their fields.

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.

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/ß 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.

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.

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.

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.

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.

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.

Role of mast cells in eosinophilic esophagitis.

PURPOSE OF REVIEW: This review will present what is known from recent research on the involvement of mast cells in eosinophilic esophagitis and identify questions requiring further investigation. RECENT FINDINGS: In the adults and children with eosinophilic esophagitis, there is increasing evidence that mastocytosis can persist, despite resolution of eosinophilia and is associated with persistent mucosal abnormalities and symptoms. Despite, treatment mast cells have an activated transcriptome. Mast cells likely contribute to epithelial barrier dysfunction, smooth muscle hypertrophy and contraction, and subepithelial fibrosis. It remains unclear whether targeting MCs alone has therapeutic efficacy to improve tissue damage. SUMMARY: Mast cells appear to play a key role in eosinophilic esophagitis and serve as a biomarker of mucosal healing in conjunction with eosinophils. Excessive mast cell activation likely contributes to tissue damage in eosinophilic esophagitis and need to be considered as a target of therapy along with eosinophils.

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.

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.