Flow cytometry as a tool for assessing reactive oxygen species-related fluorescence in peripheral blood leukocytes from children and adolescents with asthma

Background Asthma is characterized by airway inflammation and bronchial hyperreactivity, with increased production of reactive oxygen species (ROS). Assessing oxidative stress is relevant to disease pathophysiology, but many methods have limitations in pediatric populations . Objectives This study evaluated DHE- and DCF-derived fluorescence using flow cytometry and examined their associations with pulmonary function and inflammatory and immunological biomarkers in children and adolescents with asthma. Methods This is a cross-sectional study of 110 participants aged 6 to 15 years, divided into a control group ( n = 27) and an asthma group ( n = 83). Pulmonary function, eosinophil (EOS) levels, immunoglobulin E (IgE), and DHE-derived fluorescence reflecting O₂⁻-related oxidative activity and DCF-derived fluorescence reflecting H₂O₂-related oxidative activity were evaluated. Results The asthma group showed a significant reduction (from predicted values, %) in Forced Expiratory Volume in the first second (95.4 ± 15.9%) and Forced Vital Capacity (100.4 ± 16.8) compared to the control group (105.0 ± 12.0 and 109.9 ± 15.2, respectively; p = 0.004 and p = 0.01, respectively). EOS (N/mm3) and IgE (KU/L) concentrations were higher in the asthma group (447 [223–682]) and (548 [212–1091]; p = 0.005 and p = 0.002, respectively) versus the control group (237 [157–410]) and (138 [49.4–480]). DHE-derived fluorescence (reflecting O₂⁻-related oxidative activity) was higher ( p = 0.005) in asthmatics (1295 [1162–1416] MFI, a.u.) compared to controls (1129 [973–1302] MFI, a.u.). Conclusion Children and adolescents with mild-to-moderate asthma showed higher DHE-derived fluorescence than controls. Flow cytometry was feasible for quantifying ROS-related fluorescence in peripheral blood leukocytes; however, longitudinal studies are needed to determine the clinical relevance of these findings.