Validation of methods to assess potential biomarkers in pediatric patients with esophageal eosinophilia

Major basic protein is a useful marker to distinguish eosinophilic esophagitis from IBD-associated eosinophilia in children

OBJECTIVES

The incidence of eosinophilic esophagitis (EoE) is 3-5 times greater in patients with inflammatory bowel disease (IBD) compared with the general population. This study aimed to differentiate true EoE from esophageal eosinophilia in IBD patients by evaluating expression of major basic protein (MBP) and interleukin-13 (IL-13) in esophageal biopsies.

METHODS

This retrospective study included subjects who had an esophagogastroduodenoscopy with esophageal biopsies for IBD work up or suspicion for EoE. Patients were classified into 5 groups: EoE with ≥15 eosinophils per high power field (eos/hpf), EoE-IBD with ≥15 eos/hpf, IBD eosinophilia with 1-14 eos/hpf, IBD and control groups. Biopsies were stained with MBP and IL-13 antibodies and the results (% staining/total tissue area), demographic, and clinical findings were compared among the groups.

RESULTS

The median for MBP staining levels in EoE-IBD was 3.8 (interquartile range 1.3-23), significantly lower than in EoE at 52.8 (8.3-113.2), but higher than in IBD eosinophilia at 0.2 (0-0.9; p < 0.001) and negligible in the IBD and control groups. IL-13 expression in EoE was significantly higher only compared with IBD and controls not with EoE-IBD or IBD eosinophilia. MBP predicted EoE with 100% sensitivity and 99% specificity while IL-13 had 83% sensitivity and 90% specificity using cutoff point from the cohort without EoE-IBD patients. Based on MBP cutoff point that distinguished EoE from non EoE, 56% in EoE-IBD were MBP-positive whereas 100% in EoE group (p < 0.05).

CONCLUSIONS

MBP may be an excellent marker in distinguishing true EoE from eosinophilia caused by IBD. Our data implied that MBP together with endoscopic and histologic changes can assist EoE diagnosis in IBD patients.

Utility of a Noninvasive Serum Biomarker Panel for Diagnosis and Monitoring of Eosinophilic Esophagitis: A Prospective Study

OBJECTIVES

Noninvasive biomarkers would be valuable for diagnosis and monitoring of eosinophilic esophagitis (EoE). The aim of this study was to determine the utility of a panel of serum biomarkers for the diagnosis and management of EoE.

METHODS

We conducted a prospective cohort study of consecutive adults undergoing outpatient esophagogastroduodenoscopy. Incident cases of EoE were diagnosed per consensus guidelines; controls had gastroesophageal reflux disease (GERD) or dysphagia and did not meet the EoE criteria. EoE cases were treated with topical steroids and had repeat endoscopy. Pre- and post-treatment serum samples were analyzed in a blinded manner for interleukin (IL)-4, IL-5, IL-6, IL-9, IL-13, transforming growth factor (TGF)-α, TGF-β, tumor necrosis factor-α, eotaxin-1, -2, and -3, thymic stromal lymphopoietin (TSLP), major basic protein, and eosinophil-derived neurotoxin. Cases and controls were compared at baseline, and pre- and post-treatment assays were compared in cases.

RESULTS

A total of 61 incident EoE cases and 87 controls were enrolled; 51 EoE cases had post-treatment serum analyzed. There were no significant differences in any of the biomarkers between EoE cases and controls at baseline. IL-13 and eotaxin-3 for cases and controls were 85 ± 160 vs. 43 ± 161 pg/ml (P=0.12) and 41 ± 159 vs. 21 ± 73 (P=0.30). There were no significant differences in assay values among cases before and after treatment. There were also no differences after stratification by atopic status or treatment response.

CONCLUSIONS

A panel of inflammatory factors known to be associated with EoE pathogenesis were not increased in the serum, nor were they responsive to therapy. None of these biomarkers are likely candidates for a serum test for EoE. Histologic analysis for diagnosis and management of EoE continues to be necessary, and novel, less invasive, biomarkers are needed.

Markers of eosinophilic inflammation for diagnosis of eosinophilic esophagitis and proton pump inhibitor-responsive esophageal eosinophilia: a prospective study

BACKGROUND & AIMS

Distinguishing between eosinophilic esophagitis (EoE), gastroesophageal reflux disease, and proton pump inhibitor-responsive esophageal eosinophilia (PPI-REE) is challenging. We assessed whether immunohistochemical analysis of esophageal tissues for major basic protein (MBP), eotaxin-3, and tryptase can be used for diagnosis of EoE and to differentiate EoE from PPI-REE.

METHODS

We conducted a prospective study of 196 consecutive adults who underwent outpatient endoscopy at the University of North Carolina from 2009 through 2012. Incident cases of EoE were diagnosed per consensus guidelines. Patients with gastroesophageal reflux disease or dysphagia served as controls. PPI-REE was defined as a symptomatic and histologic response to a PPI. Immunohistochemistry was performed to quantify MBP, eotaxin-3, and tryptase. The maximum density of epithelial staining was determined for each assay; levels were compared between EoE and control groups and then EoE and PPI-REE groups, and receiver operating characteristic curves were constructed.

RESULTS

Esophageal tissues from patients with EoE (n = 50) had a median 951 MBP-positive cells/mm(2), whereas those from controls (n = 123) had a median 2 MBP-positive cells/mm(2) (P < .001). Samples from patients with EoE had a median 155 eotaxin-3-positive cells/mm(2), and those from controls (n = 123) had 18 eotaxin-3-positive cells/mm(2) (P < .001). Samples from patients with EoE had a median 249 tryptase-positive cells/mm(2), and those from controls (n = 123) had 11 tryptase-positive cells/mm(2) (P < .001). Levels of MBP, eotaxin-3, tryptase, and the combination of all 3 identified patients with EoE with area under the receiver operating characteristic curve values of 0.99, 0.94, 0.99, and 1.00. Analyses of only samples with eosinophil counts of 10-100 eosinophils per high-power field produced similar results. No marker distinguished EoE from PPI-REE. Esophageal tissues from patients with PPI-REE (n = 23) had 987 MBP-positive cells/mm(2) (P = .18, compared with EoE), 160 eotaxin-3-positive cells/mm(2) (P = .33), and 243 tryptase-positive cells/mm(2) (P = .28).

CONCLUSIONS

Esophageal tissues from patients with EoE have substantially higher levels of MBP, eotaxin-3, and tryptase than controls on the basis of immunohistochemical analysis. Assays for the 3 markers identify patients with EoE with 100% accuracy but cannot distinguish EoE from PPI-REE.

Diagnostic and therapeutic strategies for eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a recently recognized allergic disorder, characterized by eosophageal dysfunction, accumulation of ≥15 eosinophils/high-powered field, eosinophil microabssess, basal cell hyperplasia, extracellular eosinophilic granules in the esophageal epithelial mucosal biopsy and a lack of response to a 8-week proton pump inhibitor treatment. Despite the increased incidences and considerable progress made in understanding EoE pathogenesis, there are limited diagnostic and therapeutic options available for EoE. Currently, the only criterion for diagnosing EoE is repetitive esophageal endoscopic biopsies and histopathological evaluation. Antigen elimination or corticosteroid therapies are effective therapies for EoE but are expensive and have limitations, if continued in the long term. Hence, there is a great necessity for novel noninvasive diagnostic biomarkers that can easily diagnose EoE and assess effectiveness of therapy. Herein, we have provided an update on key molecules involved in the disease initiation, and progression and proposed novel noninvasive diagnostic molecules and strategies for EoE therapy.