The oesophageal string test: a novel, minimally invasive method measures mucosal inflammation in eosinophilic oesophagitis

Abstract

ObjectiveEosinophil predominant inflammation characterises histological features of eosinophilic oesophagitis (EoE). Endoscopy with biopsy is currently the only method to assess oesophageal mucosal inflammation in EoE. We hypothesised that measurements of luminal eosinophil-derived proteins would correlate with oesophageal mucosal inflammation in children with EoE.DesignThe Enterotest diagnostic device was used to develop an oesophageal string test (EST) as a minimally invasive clinical device. EST samples and oesophageal mucosal biopsies were obtained from children undergoing upper endoscopy for clinically defined indications. Eosinophil-derived proteins including eosinophil secondary granule proteins (major basic protein-1, eosinophil-derived neurotoxin, eosinophil cationic protein, eosinophil peroxidase) and Charcot–Leyden crystal protein/galectin-10 were measured by ELISA in luminal effluents eluted from ESTs and extracts of mucosal biopsies.ResultsESTs were performed in 41 children with active EoE (n=14), EoE in remission (n=8), gastro-oesophageal reflux disease (n=4) and controls with normal oesophagus (n=15). EST measurement of eosinophil-derived protein biomarkers significantly distinguished between children with active EoE, treated EoE in remission, gastro-oesophageal reflux disease and normal oesophagus. Levels of luminal eosinophil-derived proteins in EST samples significantly correlated with peak and mean oesophageal eosinophils/high power field (HPF), eosinophil peroxidase indices and levels of the same eosinophil-derived proteins in extracts of oesophageal biopsies.ConclusionsThe presence of eosinophil-derived proteins in luminal secretions is reflective of mucosal inflammation in children with EoE. The EST is a novel, minimally invasive device for measuring oesophageal eosinophilic inflammation in children with EoE.

La mystérieuse œsophagite à éosinophiles garde encore quelques secrets

“…Les outils de la biologie moléculaire permettrontd 'identifier les patients EoE de manière plus certaine, et sansd oute de définir des sous-groupesd ep atients qui bénéficieront d'une approche personnalisée [ 11,12,13]. Des approches non-invasives d'échantillonnage de la muqueuse oesophagienne prometteuses devraient permettre de moins recourir à l'endoscopie [77,78]. Parailleurs, de nouveaux scores d'activité clinique ou histologiques validésp ermettrontd esoutenir un développement clinique robuste [79,15].…”

Esofagite eosinofílica na infância

“…Se a histologia da mucosa esofagiana permanecer inalterada o diagnóstico de EEo deve ser prioritariamente considerado. O diagnóstico diferencial é feito com Doença do Refluxo Gastresofagiano (DRGE), acalasia, doença celíaca, doença de chron, doenças do tecido conjuntivo, reação do enxerto, hipersensibilidade a drogas e síndromes hipereosinofílicas (9,10).…”

Accuracy of liquid cytology in the diagnosis and monitoring of eosinophilic oesophagitis

“…14 One approach that has recently been shown effective as a semi-invasive method is the determination of eosinophil granule proteins in oesophageal intraluminal secretions obtained using a device designed for the study of Helicobacter pylori and intestinal bacterial flora (oesophageal string test). 15 However, this strategy, although attractive, has several drawbacks such as laborious sample processing, which brings difficulty to carry out the analysis in non-tertiary centres and discomfort for the patient who, after swallowing the string-capsule, must keep it overnight for subsequent extraction. One possible strategy is diagnostic cytology of the oesophagus using the Cytosponge, which has proven to be useful in the monitoring of Barrett's oesophagus, 16 being a cost-effective screening approach for oesophageal cancer.…”