D3.179 - Longitudinal breath profiling of exhaled volatile organic compounds differentiates viral-induced asthma exacerbation from clinical control

Respiratory viral infections are the leading trigger of asthma exacerbations. However, objective non-invasive tools capable of distinguishing active viral exacerbation from subsequent clinical recovery remain limited.

Objective:

To evaluate whether longitudinal analysis of exhaled volatile organic compound (VOC) profiles differentiates viral-induced asthma exacerbation from subsequent clinical control.

We conducted a prospective longitudinal study including 22 patients hospitalized for virologically confirmed asthma exacerbation. Twelve patients completed follow-up reassessment 9–13 weeks after discharge, once asthma control was achieved according to GINA 2024 criteria and the Asthma Control Test (ACT). Twelve healthy subjects were included as controls.

Exhaled breath was analyzed using a 24-sensor electronic nose (eNose). Sensor responses were compared across disease phases and groups. Principal component analysis (PCA) was applied for multivariate discrimination.

Twelve patients (median age 37 years, 66% female) completed longitudinal evaluation. Eleven of 24 sensors significantly differentiated uncontrolled from controlled asthma (p<0.05), with sensors 7 and 16 showing the strongest discrimination (p<1×10⁻⁴).

Controlled asthma differed from healthy subjects in all 24 sensors (p<0.05), whereas 16 sensors differentiated uncontrolled asthma from healthy controls.

PCA demonstrated clear separation among uncontrolled asthma, controlled asthma, and healthy subjects. The first two principal components explained 87.8% of total variance. No significant differences were observed according to baseline asthma severity once control was achieved.

Longitudinal breath profiling demonstrates that exhaled VOC signatures dynamically reflect transitions from viral asthma exacerbation to clinical control. eNose-based analysis may represent a promising non-invasive biomarker to monitor recovery following virus-associated exacerbations.