875:
Blood Eosinophil Beta1-Integrin Activation Correlates with Eosinophilic Esophagitis (EoE) Disease Activity
Monday, March 5, 2018
South Hall A2 (Convention Center)
Mats W Johansson, PhD, Michael D Evans, MS, Elizabeth McKernan, BS, Paul S Fichtinger, BS, Evelyn L Angulo, MD, Deane F Mosher, MD, Shelly M Cook, MD, Eric A Gaumnitz, MD, Sameer K Mathur, MD PhD FAAAAI
RATIONALE: Monitoring of EoE would benefit from biomarkers to replace invasive endoscopy and pathology. We hypothesized that beta1-integrin activation, which enables arrest of eosinophils in inflamed vessels and predicts disease activity in non-severe asthma, correlates with eosinophilic inflammation and disease activity in EoE.

METHODS: Ten EoE patients were recruited following two-month proton-pump-inhibitor therapy and diagnostic endoscopy, with visit 1 (V1) within one week of endoscopy. Patients received standard of care EoE treatment (swallowed steroid or food elimination) followed by visit 2 and repeat endoscopy (V2) two months later. Beta1-integrin activation (mAb N29 intensity) and 15 other eosinophil-surface markers were assayed by whole blood flow cytometry. The EoE Histological Scoring System (EoEHSS), including an eosinophilic inflammation subscore of 0 to 3, was used.

RESULTS: N29 correlated with eosinophilic inflammation subscore (rs/Spearman coefficient=0.91, p=0.001) or EoEHSS total score (rs=0.70, p = 0.03) at V2 but not V1. Further, the change in N29 from V1 to V2 correlated with inflammation subscore change (rs=0.81, p=0.007). The five patients for whom N29 was increased the most at V2 had mean subscore of 1.6±0.9 after a change of -1.0±0.7, whereas the five patients for whom N29 increased less or decreased (a mean decrease) the subscore was 0.0±0.0 after a change of -2.8±0.4 (p=0.008 for the subscore and 0.02 for change).

CONCLUSIONS: In this pilot study, persistent beta1-integrin activation on circulating eosinophils after EoE treatment was associated with residual esophageal eosinophilic inflammation, whereas a decrease in beta1-integrin activation was associated with resolution of eosinophilic inflammation.