440:
Eosinophil progenitor levels correlate with disease activity as assessed by the eosinophilic esophagitis histologic scoring system in pediatric eosinophilic esophagitis
Sunday, March 4, 2018
South Hall A2 (Convention Center)
Justin T Schwartz, MD PhD, David W. Morris, MD, Margaret H Collins, MD, Marc E Rothenberg, MD PhD FAAAAI, Patricia C. Fulkerson, MD PhD
RATIONALE: The EoE histologic scoring system (EoEHSS) provides a standardized method to assess disease activity in eosinophilic esophagitis (EoE). Eosinophil progenitor (EoP) levels show promise as a minimally invasive biomarker for monitoring EoE. We investigated whether EoP levels correlated with EoEHSS-assessed disease activity.

METHODS: Pediatric patients (1-18 years old) with EoE were divided into groups by peak esophageal eosinophil biopsy count—active disease (n= 17, ≥15 eosinophils/high-powered field (hpf)) and inactive disease (n= 14, <15 eosinophils/hpf). EoPs were quantified in the peripheral blood by flow cytometry. Biopsies underwent blinded evaluation by a pathologist to determine the EoEHSS score. Spearman correlations were calculated.

RESULTS: Patients with active EoE had increased EoEHSS composite scores (Mann Whitney test; P < 0.001), and EoEHSS composite scores positively correlated with esophageal eosinophil numbers (P < 0.001) and peripheral blood EoP levels (P = 0.02). EoE grade and stage also demonstrated significant correlation with EoP levels (P = 0.002 and P = 0.005, respectively). EoP levels directly correlated with several pathologic, EoEHSS-assessed features, including eosinophil inflammation (P = 0.02), dilated intercellular spaces (P = 0.03), and basal zone hyperplasia (P = 0.02). Notably, absolute eosinophil count (AEC) in the peripheral blood did not correlate with EoEHSS composite scores (P = 0.29).

CONCLUSIONS: Peripheral blood EoP levels correlate with the EoEHSS and outperform AEC in association with histologic changes in EoE. These data provide further support for the utility of using the EoEHSS to assess disease activity and using EoP levels as a disease-monitoring biomarker in pediatric EoE.