# Elevated Proportions of Circulating CXCR5+ Follicular Helper T Cells Reflect the Presence of Airway Obstruction in Asthma

## TL;DR

This study shows that higher levels of a specific type of immune cell, CXCR5+ follicular helper T cells, are linked to airway obstruction in asthma patients.

## Contribution

The study identifies CXCR5+ follicular helper T cells as a novel biomarker for airway obstruction in asthma.

## Key findings

- CXCR5+ follicular helper T cells are elevated in asthma patients with %FEV1 < 80%.
- These cells correlate negatively with lung function and positively with blood eosinophils.
- They may reflect persistent type 2 inflammation causing airway obstruction.

## Abstract

Using flow cytometry, we identified and quantified Group 2 innate lymphocytes, T helper 2 cells, follicular helper T cells, and T helper 17 cells in peripheral blood samples from 49 individuals with asthma. We then conducted cross-sectional analyses to assess relationships between levels of these immune cells and lung function parameters, including the percentage predicted forced expiratory volume in 1 s (%FEV1). We also examined correlations between the proportions of immune cells and type 2 biomarkers.

Proportions of CXCR5+ follicular helper T cells in human peripheral blood, as opposed to Group 2 innate lymphoid cells (ILC2) or T helper 2 cells, were significantly higher in cases with %FEV1 < 80% compared to those with %FEV1 ≥ 80%. Further, these proportions correlated negatively with %FEV1 and positively with blood eosinophil counts.

The proportion of circulating follicular helper T cells, but not T helper 2 cells or Group 2 innate lymphoid cells, may reflect the presence of airway obstruction caused by persistent type 2 inflammation.