{
  "abstract": "Introduction Eosinophilic oesophagitis (EoE) is a chronic immune-mediated oesophageal disease causing dysphagia and food bolus obstruction. Diagnosis and monitoring currently rely on repeated endoscopy with biopsy demonstrating ≥15 eosinophils/0.3 mm 2, an invasive and resource intensive approach that can correlate poorly with symptoms. Minimally invasive luminal sampling using a swallowed oesophageal string test may offer an alternative method of assessing mucosal inflammation. We aimed to evaluate the relationship between string test derived biomarkers and disease activity, and to compare their performance across validated histological, endoscopic and symptom measures.Methods Adults with EoE were prospectively recruited as part of a research study (EoEAST, IRAS 303427). Patients underwent gastroscopy (OGD) with histological assessment (peak eosinophil count and EoE Histology Scoring System [EoE-HSS]), endoscopic grading using EREFS, and symptom evaluation using validated patient reported outcome measures (RDQ, HODQ, and EoE-QoL). Same day oesophageal luminal sampling was performed using a swallowed coiled oesophageal string test (CEST), with subsequent protein extraction and ELISA quantification of eosinophil cationic protein (ECP), eosinophil-derived neurotoxin (EDN), periostin and plasminogen activator inhibitor-1 (PAI-1). Correlations were assessed using Spearman analysis. Logistic regression and ROC analysis evaluated active disease (>15 eos/0.3 mm 2).Results 70 patients were included (median age 42 years, range 20–67). ECP showed the strongest and most consistent associations with disease activity, correlating with peak eosinophil count (r=0.27, p=0.002), EoE-HSS (r=0.33, p=0.0002), and total EREFS (r=0.31, p=0.0003). EDN also correlated with histological activity (peak eos r=0.25, p=0.031; EoE-HSS r=0.32, p=0.006), while periostin showed weaker associations and PAI-1 showed none. Log-transformed ECP independently predicted active disease on logistic regression (OR 2.59, 95% CI 1.44–4.67, p=0.002). ROC analysis demonstrated moderate discrimination for ECP (AUC 0.64, p=0.007), EDN (AUC 0.65, p=0.034) and periostin (AUC 0.64, p=0.006), but not PAI-1.Conclusions CEST captures luminal biomarkers associated with objective disease activity in EoE. ECP was the most robust biomarker, independently predicting active inflammation and outperforming other candidates. Biomarker levels aligned more closely with histological and endoscopic severity than symptoms, supporting minimally invasive luminal sampling as a promising adjunct for EoE disease assessment.",
  "authors": [
    {
      "affiliations": [
        "Guys and St Thomas’ NHS Foundation Trust, London, United Kingdom",
        "St George’s University Hospitals NHS Foundation Trust, London, United Kingdom",
        "City, St George’s University of London, London, United Kingdom"
      ],
      "name": "Joseph Cooney"
    },
    {
      "affiliations": [
        "University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom"
      ],
      "name": "Okanda Ogbonda"
    },
    {
      "affiliations": [
        "St George’s University Hospitals NHS Foundation Trust, London, United Kingdom"
      ],
      "name": "Priscilla Appiahene"
    },
    {
      "affiliations": [
        "St George’s University Hospitals NHS Foundation Trust, London, United Kingdom"
      ],
      "name": "David Bean"
    },
    {
      "affiliations": [
        "St George’s University Hospitals NHS Foundation Trust, London, United Kingdom"
      ],
      "name": "Heung Chong"
    },
    {
      "affiliations": [
        "University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom"
      ],
      "name": "Efrem Eren"
    },
    {
      "affiliations": [
        "St George’s University Hospitals NHS Foundation Trust, London, United Kingdom",
        "City, St George’s University of London, London, United Kingdom"
      ],
      "name": "Jamal Hayat"
    }
  ],
  "title": "O87 Minimally invasive coiled oesophageal string test identifies ECP as a biomarker of active eosinophilic oesophagitis",
  "uid": "a3ab086b-44d9-559f-bba8-2d45f6e86498"
}