The following is a summary of “Airway hyperresponsiveness correlates with airway TSLP in asthma independent of eosinophilic inflammation,” published in the April 2024 issue of Allergy & Immunology by Andreasson, et al.
Thymic stromal lymphopoietin (TSLP) is a cytokine released by the airway epithelium in response to various environmental triggers, contributing to type-2 inflammatory responses associated with asthma. While TSLP’s role in airway inflammation and hyperresponsiveness is recognized, its association with asthma phenotypes and its direct effects on airway smooth muscle and mast cells remain underexplored. For a study, researchers sought to investigate the relationship between airway hyperresponsiveness (AHR) and levels of TSLP in serum, sputum, and bronchoalveolar lavage fluid in patients with asthma, with and without type-2 inflammation.
Using a novel ultrasensitive assay, TSLP levels were measured in patients with asthma (serum: n = 182; sputum: n = 81; bronchoalveolar lavage: n = 85) and healthy controls (serum: n = 47). The study assessed the distribution and association among airway and systemic TSLP levels, AHR measures, type-2 inflammation markers, and disease severity.
Sputum TSLP levels correlated with AHR independently of eosinophil counts and fractional exhaled nitric oxide (ρ = 0.49, P = .005). Serum TSLP levels were higher in both eosinophil-high and eosinophil-low asthma groups compared to healthy controls: geometric mean 1,600 fg/mL (95% CI: 1,468-1,744 fg/mL) and 1,294 fg/mL (95% CI: 1,167-1,435 fg/mL) versus 846 fg/mL (95% CI: 661-1,082 fg/mL), but did not correlate with AHR. Higher serum TSLP levels were associated with increasing age, male sex, and blood eosinophil counts, while lung function, inhaled corticosteroid dose, and symptom scores showed no association.
The study findings suggested that sputum TSLP levels were associated with AHR to mannitol regardless of type-2 inflammation markers, indicating a role for TSLP in AHR partly independent of eosinophilic inflammation. It underscored the complex interplay between TSLP and asthma pathophysiology, highlighting its potential as a therapeutic target for asthma management.
Reference: sciencedirect.com/science/article/abs/pii/S0091674923024090