Serum eosinophilic cationic protein is correlated with food impaction and endoscopic severity in eosinophilic esophagitis

Eosinophilic esophagitis: absolute eosinophilic count, peak eosinophilic count, and potential biomarkers of eosinophilic degranulation products-an in-depth systematic review

Background

Eosinophilic esophagitis is a chronic inflammatory disorder, often relapsing. There is an increasing need to develop new alternative diagnostic and monitoring methods on a critical basis, which will provide samples through none or minimally invasive procedures. This study aims to identify and document the types and roles of potential biomarkers in eosinophilic esophagitis released by eosinophils as well as the potential relationship to the peak eosinophilic count and the degree of degranulation of in situ eosinophils (DGE/DGE + NDGE: degranulated eosinophils/degranulated eosinophils and non-degranulated eosinophils).

Methods

This is the first in-depth systematic review study using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) parameters involving a literature search of academic databases (PubMed, Scopus, Medline, Google Scholar, and Cochrane Database, 2011-2022) targeting specifically the eosinophilic counts and ratio, and the eosinophilic degranulation products as potential biomarkers. Data were extracted from ten selected studies and presented on a spreadsheet.

Results

The studies show the ability to detect eosinophilic and non-eosinophilic degranulation products, and absolute eosinophilic count in samples, including blood and urine, thereby serving as potential surrogates in making the diagnosis or monitoring disease progression in the future. There is an obvious paucity of studies that correlate potential biomarkers to the degree of degranulation of in situ eosinophils.

Conclusions

A few minimally invasive methods and biomarkers may be suggested as alternative tools in diagnosing and monitoring eosinophilic esophagitis. While there is no consensus on the clinical usefulness of these biomarkers, our critical evaluation may suggest that the eosinophilic degranulation ratio (DGE/DGE + NDGE: degranulated eosinophils/degranulated eosinophils and non-degranulated eosinophils) in the esophagus may be critical for evaluating properly these biomarkers. An increasing trend may culminate in the potential clinical use of these biomarkers evaluated not only with the peak eosinophilic count, but also with the degranulation score upon regulatory bodies' approval to monitor eosinophilic esophagitis in the future. We strongly advocate for the necessity to score the esophageal biopsies with both a peak eosinophilic count and a score of the degranulated eosinophils.

Differential diagnostics of food allergy as based on provocation tests and laboratory diagnostic assays

Due to the scale of the phenomenon, food allergy constitute a significant health problem and significantly impair the quality of life of patients. Differential diagnostics, including skin tests, sIgE detection tests, basophil and mast cell activation tests as well as double-blind placebo-controlled food challenge tests, is the gold standard in the diagnosis of food allergy. Recently, increasing attention has been paid to the potential use of nasal provocation test in the diagnosis of food allergy. Allergen dose, protocol standardization, assessment of subjective complaints and objectivization of test results are important factors determining the applicability of provocation tests.

Non-Invasive and Minimally Invasive Biomarkers for the Management of Eosinophilic Esophagitis beyond Peak Eosinophil Counts: Filling the Gap in Clinical Practice

Eosinophilic esophagitis (EoE) is a chronic esophageal disease that needs lifelong management and follow-up. The diagnosis requires an upper endoscopy with at least one esophageal biopsy demonstrating >15 eosinophils/high-power field, and often occurs with a diagnostic delay of up to ten years, partly due to the absence of valid non-invasive screening tools. In addition, serial upper endoscopies with esophageal biopsies are mandatory to assess the efficacy of any ongoing treatment in patients with EoE. These procedures are invasive, costly, and, when performed without sedation, are often poorly tolerated by patients. Therefore, there is the clinical need to identify reliable non-invasive or minimally invasive biomarkers that could be used to assess disease activity in clinical practice as a surrogate of peak eosinophil counts on esophageal biopsies. This review summarizes evidence on investigational non-invasive or minimally invasive biomarkers for the diagnosis and follow-up of EoE to report on the state of the art in the field and support future research. We discussed eosinophil-derived mediators including eosinophil cationic protein (ECP), eosinophil-derived neurotoxin (EDN, also known as eosinophil protein X), eosinophil peroxidase (EPO), and major basic protein (MBP) as well as other promising non-eosinophil-derived biomarkers. Although several studies have shown the utility of most biomarkers collected from the serum, esophageal luminal secretions, and feces of EoE patients, numerous limitations currently hamper the integration of such biomarkers in clinical practice. Future studies should aim at validating the utility of non-invasive and minimally invasive biomarkers using rigorous protocols and updated consensus criteria for EoE.

Blood-Based Biomarkers for Eosinophilic Esophagitis and Concomitant Atopic Diseases: A Look into the Potential of Extracellular Vesicles

Eosinophilic esophagitis (EoE) is a chronic, Th2-inflammatory disease of the esophagus that can severely affect food intake. Currently, diagnosis and assessing response to treatment of EoE is highly invasive and requires endoscopy with esophageal biopsies. Finding non-invasive and accurate biomarkers is important for improving patient well-being. Unfortunately, EoE is usually accompanied by other atopies, which make it difficult to identify specific biomarkers. Providing an update of circulating EoE biomarkers and concomitant atopies is therefore timely. This review summarizes the current knowledge in EoE blood biomarkers and two of its most common comorbidities, bronchial asthma (BA) and atopic dermatitis (AD), focusing on dysregulated proteins, metabolites, and RNAs. It also revises the current knowledge on extracellular vesicles (EVs) as non-invasive biomarkers for BA and AD, and concludes with the potential use of EVs as biomarkers in EoE.

Clinical presentation and endoscopic findings in adult patients with eosinophilic esophagitis

Background/Aim: The frequency of eosinophilic esophagitis has been rising over the last decades. It is diagnosed primarily based on symptoms and endoscopic and histopathological examination findings. Although eosinophilic esophagitis is not associated with malignancy, it remains an important condition affecting both children and adults, as it is associated with morbidity such as dysphagia, food impaction, and esophageal strictures. This study aimed to define clinical and endoscopic characteristics of adult patients diagnosed with eosinophilic esophagitis based on recently recommended histopathological criteria. Methods: This retrospective cross-sectional descriptive study included 54 adult patients (mean age: 33.6 yr, range: 16–61 yr) who underwent upper gastrointestinal system endoscopy for dyspeptic complaints (epigastric pain, reflux, dysphagia, or food impaction) and diagnosed with eosinophilic esophagitis based on the latest histopathological criteria (≥15 eosinophils per high-power field). Patients with a history of malignancy were excluded. Patients’ clinical, endoscopic, and histopathological data were examined. Results: In patients diagnosed with eosinophilic esophagitis, the most common presenting complaint was dysphagia (61.1%), followed by dyspepsia (24.0%), regurgitation (16.6%), chest pain (16.6%), epigastric pain (12.9%), food impaction (11.1%), and halitosis (3.7%), without any age predilection for the complaints. White papules and linear furrow were the most frequent findings on endoscopic examination (35.1% each), followed by circular rings (24.0%), paleness (22.2%), normal endoscopic finding (20.3%), and small-caliber esophagus (11.1%). Conclusion: The diagnosis of eosinophilic esophagitis remains challenging due to considerable variations in definitions and in the relative frequencies of endoscopic findings. Therefore, we recommend combining clinical, endoscopic, and histologic criteria to establish diagnosis. The identification of standards for diagnosis in future studies is warranted.