Eosinophil Involvement Outside the Esophagus in Eosinophilic Esophagitis.

Eosinophilic gastrointestinal diseases (EGIDs) are chronic, immune-mediated disorders, characterized clinically by gastrointestinal (GI) symptoms and histologically by eosinophil-predominant infiltration in ≥1 GI tract segment.1 A recent, international consensus by 91 experts proposed a new framework for EGID nomenclature to establish updated terms, designations, and conventions.2 Although this framework offers a standardized starting point for the field, debate is ongoing regarding the appropriate terminology for cases involving multiple areas, such as "non-eosinophilic esophagitis (EoE) EGID and EoE" or "non-EoE EGID with esophageal involvement (EI)." Notably, in a survey of these experts, 61% agreed with the later term "non-EoE EGID with EI," because EoE is isolated to the esophagus by current diagnostic criteria.3 However, limited molecular and pathogenic data exist to support the distinction. Furthermore, disease burden of symptoms and comorbidities generally is higher in non-EoE EGIDs than EoE.4 Presently, there is no screen to predict non-EoE EGID concomitance in EoE; therefore, decision-making to further explore other GI segment involvement is clinically challenging. We aimed to answer 2 fundamental questions in the field (Figure 1A): Is there a shared or distinct pathogenesis between patients with isolated EoE and non-EoE EGIDs with EI as assessed by patient characteristics and molecular profiles? Can we predict concomitant non-EoE EGIDs when EoE exists? Herein, we report a similar molecular signature between EoE and EI and a potential predictive model to identify concomitant non-EoE EGIDs in patients with EoE.

Genetic and Molecular Contributors in Eosinophilic Esophagitis.

PURPOSE OF REVIEW: Eosinophilic esophagitis (EoE) is an allergic inflammatory esophageal disorder with a complex underlying genetic and molecular etiology. The interest of the scientific community in EoE has grown considerably over the past three decades, and the understanding of the genetic and molecular mechanisms involved in this disease has greatly increased. RECENT FINDINGS: In this article, we aim to provide both historic aspects and updates on the recent genetic and molecular advances in the understanding of EoE. Although EoE is a relatively newly described disorder, much progress has been made toward identifying the genetic and molecular factors contributing to the disease pathogenesis by a variety of approaches with next-generation sequencing technologies, including genome-wide association study, whole exome sequencing, and bulk and single-cell RNA sequencing. This review highlights the multifaceted impacts of various findings that have shaped the current molecular and genetic landscape of EoE, providing insights that facilitate further understanding of the disease process.

Nonepithelial 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 metric with a broad spectrum of esophageal transcripts to uncover potential symptom pathogenesis. METHODS: We extracted data from 146 adults with EoE through the Consortium of Eosinophilic Gastrointestinal Disease Researchers. Patients were subgrouped by esophageal dilation history. We compared a validated patient-reported outcome 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 used 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 nonepithelial cells and three in epithelial cells. During histologic remission, only four of 11 nonepithelial genes (36%) versus all three epithelial genes (100%) had decreased expression to less than 50% of that in active EoE. Fibroblasts expressed five of 11 nonepithelial EEsAI-associated EDP genes (45%). A subset of nonepithelial genes (eight of 11; 73%), but not EoE-representative genes (none of four; 0%; CCL26, CAPN14, DSG1, and SPINK7), was upregulated in patients with EoE with the highest versus lowest symptom burden. CONCLUSION: The correlation of symptoms and nonepithelial esophageal gene expression substantiates that nonepithelial cells (eg, fibroblasts) likely contribute to symptom severity.