# Investigating immune profile by CyTOF in patients with eosinophilic esophagitis after treatment with orodispersible budesonide

## TL;DR

This study uses CyTOF to analyze immune profiles in patients with eosinophilic esophagitis before and after treatment with budesonide, revealing changes in immune cell populations and potential biomarkers.

## Contribution

The study identifies specific immune cell changes in EoE patients post-treatment and links them to clinical outcomes.

## Key findings

- EoE patients had lower effector memory T cells post-treatment, matching healthy subjects.
- Levels of galectin-10+ eosinophils correlated with histological findings in EoE patients.
- 90% of patients showed histological remission after treatment with budesonide.

## Abstract

Eosinophilic esophagitis (EoE) is a chronic Th2-mediated inflammatory disease of the esophagus driven by dietary or inhalant allergens which if left untreated, leads to fibrosis and poor esophageal function. Although the inflammation in the esophagus is dominated by eosinophils, there are also elevated levels of T and B cells. Blood samples from ten patients with EoE before and after treatment with orodispersible budesonide and 10 healthy controls were compared using cytometry by time-of-flight. An antibody panel was designed that covers the major immunological cell populations with a particular focus on eosinophils. The data was analyzed with multivariate methods and cluster analysis. Correlation analysis was done between immune markers and endoscopic, histological, and symptomatologic assessments. Our analysis revealed that patients with EoE had lower levels of effector memory T cells after treatment with orodispersible budesonide to the same level as healthy subjects. In addition, more suppressive eosinophils were present in the circulation of EoE patients before treatment and more immature eosinophils were present after treatment. Furthermore, levels of galectin-10+ eosinophils correlated with histological findings in esophageal tissue from EoE patients. In all patients, the peak eosinophils were decreased after treatment with orodispersible budesonide. Intriguingly, 90% of the patients had remission in the histological assessment and 50% improved in the endoscopic assessment. This study reports a detailed immune profile in patients with EoE before and after treatment with orodispersible budesonide and it is a step toward finding blood-based immune parameters that could be useful to monitor response to treatment.

(A) Minimum spanning tree of eosinophil populations present in the blood of 10 patients with EoE before and after treatment with orodispersible budesonide as well as healthy subjects (HS) determined by X-shift clustering analysis. The sizes of the circles represent the sizes of the populations. The color of the circles indicates the levels of galectin-10, FOXP3, CD16, CD274 (PD-L1), IL-5R, and IL-2R expression as shown by the heat-map scale. Numbers indicate populations that are altered after treatment [1–3 ]. Phenotypes of populations 1–3 are shown below. (B) OPLS-DA was done to see which eosinophil markers could separate EoE patients before and after treatment (n  = 10). (C) Loading plots with jackknife confidence intervals for the eosinophil markers are shown as boxes with ticks. The markers closely positioned to the patient categories are positively associated with the patient category in question. The generated two-component model had an explanatory power of 53% (goodness of fit R2Y = 0.53) and stability of 37% (Q2Y = 0.37).

Graphical Abstract