# Systemic inflammatory biomarkers in relation to lung function and exercise‐induced bronchoconstriction in adolescents

## TL;DR

This study explores how systemic inflammation in adolescents relates to lung function and exercise-induced bronchoconstriction, finding that higher levels of a specific protein, CCL19, are linked to poorer lung function.

## Contribution

The study identifies CCL19 as a novel biomarker associated with baseline lung function and small airway dysfunction in adolescents.

## Key findings

- Higher CCL19 levels are significantly associated with lower FEV1% predicted and lower X5 z-scores at baseline.
- Five proteins showed significant interactions with atopy in relation to exercise-induced bronchoconstriction.

## Abstract

The forced oscillation technique (FOT) complements spirometry in assessing lung function, with higher sensitivity to small airway dysfunction. Systemic inflammation is thought to influence lung development and exercise‐induced bronchoconstriction (EIB), but its relationship to circulating inflammatory proteins in adolescents is unclear.

To investigate associations between systemic inflammatory biomarkers and baseline lung function and post‐exercise airway responses in adolescents.

In 143 adolescents (13–15 years) from a population‐based cohort, baseline spirometry, FOT, and baseline blood samples were obtained. Participants completed an exercise challenge to assess EIB via changes in forced expiratory volume in 1 s (FEV1), resistance at 5 Hz (R5), and reactance at 5 Hz (X5). Plasma protein levels were measured using the proximity extension assay technique (Olink Target Inflammation and Immune Response panels). Associations with lung function (FEV1% predicted, R5, and X5 z‐scores) and post‐exercise responses (∆FEV1, ∆R5, ∆X5) were analyzed using linear regression with false discovery rate correction. Interaction with atopy was also examined.

Higher plasma levels of C‐C motif chemokine 19 (CCL19) were significantly associated with lower FEV1% predicted and lower X5 z‐scores at baseline, indicating reduced lung function and impaired small airway function. No proteins were associated with post‐exercise airway responses after correction. Five proteins showed significant interactions with atopy in relation to EIB.

Elevated CCL19 may reflect systemic inflammatory processes contributing to impaired lung function in early adolescence. The observed atopy‐related interactions suggest the need to consider atopy in studies of systemic inflammation and airway physiology.