Alpha-1 antitrypsin is elevated in exhaled breath condensate and serum in exacerbated COPD patients.

Summary: Background: Exacerbations of chronic obstructive pulmonary disease (COPD) significantly contribute to COPD-related morbidity. Diagnosis of COPD exacerbations may be improved by analyzing biomarkers such as alpha-1 antitrypsin (AAT). AAT is an acute-phase protein and inhibitor of neutrophil elastase. Deficiency of AAT may result in early-onset respiratory symptoms. Measurement of exhaled breath condensate (EBC) is a noninvasive method to investigate biomarkers present in the epithelial lining fluid, such as AAT. Objective: To investigate whether AAT can be detected and quantified in EBC and to compare AAT levels in the EBC of healthy controls, patients with COPD, and during exacerbations of COPD. Methods: EBC from 10 healthy controls, 17 subjects with COPD, and 18 subjects with exacerbations of COPD was collected with the RTube™ device. AAT from EBC and serum were quantified by ELISA. Results: AAT in EBC was detectable in every individual. Patients with exacerbations of COPD had significantly increased AAT values (mean, 514.33pg/mL, [SD 279.41 ]) compared with healthy controls (mean, 251.32pg/mL, [SD 44.71]) and stable COPD patients (mean, 242.01pg/mL [SD 65.74]) (P =0.0003; P =0.00003). EBC AAT showed only a correlation trend with serum AAT (r =0.3, P =0.054). Conclusions: AAT in EBC was detectable and quantifiable. AAT measured in EBC was significantly increased during exacerbations of COPD and can potentially be used as a biomarker in exacerbations. [Copyright &y& Elsevier]