Changes in admission-discharge urinary glutathione sulfonamide levels in CF

Abstract

Introduction/Aim: Acute pulmonary exacerbations, particularly those requiring hospitalisation, are significantly correlated with loss of lung function and adverse lung health outcomes for patients with cystic fibrosis (CF). There is an urgent need to explore and develop sensitive, non-invasive biomarkers for use in this population. Urinary GSA levels have been shown to correlate well with GSA levels in BAL samples and other markers of neutrophilic inflammation (MPO, allantoin, IL-8), suggesting that urinary GSA may be suitable for identifying and tracking inflammatory disease activity for patients with CF. Methods: We recruited 102 children (median age 11.5 years, 25%-75% 6.4-14.4) and 64 adults (median age 32.5 years, 25%-75% 25.0-39.0) who were admitted to hospital for management of an acute pulmonary exacerbation and/or eradication of infectious agents such as P. aeruginosa, S. aureus or Aspergillus . Urine samples were collected at admission and discharge, and GSA measured by liquid chromatography with mass spectrometry (LC-MS). Paired admission-discharge urinary GSA results were compared using Wilcoxon signed rank test. Data from children and adults were analysed separately. Results: Matched admission-discharge samples were available for 49 children and 60 adults. For children, a statistically significant difference was observed between admission and discharge results (Table 1). For adults, no statistically significant difference was observed between admission and discharge results. Thirty-four children (69.3%) and thirty-six adults (60%) had lower GSA results on discharge compared to admission. Spearman's correlation analysis identified a correlation between urinary GSA levels and age, sex, inflammatory markers, and P. aeruginosa infection for children only. Conclusion: Our preliminary findings suggest that urinary GSA is responsive to the resolution of an acute pulmonary exacerbation and correlates with subjective and objective measures of disease activity for children with CF.