Abstract
Pentraxins are a family of acute-phase reactants and pentraxin-3 (PTX3) is the prototypic long pentraxin. PTX3 has a protective role against pathogens including influenza viruses and both pro- and anti-inflammatory actions of PTX3 are described. The role of PTX3 in virus-induced COPD exacerbations is unknown.
Methods: We infected 3 groups of subjects–COPD GOLD stage II (N=20), smokers with normal lung function (SMK,N=21) and non-smokers (NS,N=11)–with rhinovirus (RV). Induced sputum was collected on 6 time points post-inoculation, cytospins prepared and cell counts determined. PTX3 and neutrophil elastase (NE) were measured in sputum supernatants by ELISA and sputum virus load by quantitative PCR.
Results: Following RV infection PTX3 in sputum was significantly increased over baseline in the COPD group and the SMK but not the NS.
PTX3 levels were higher in the COPD group compared to the NS on days 9, 12, 15 and 21 and compared to the SMK on day 15. Peak sputum PTX3 levels correlated with peak sputum virus load (P=0.0002, r=0.51), peak total sputum inflammatory cells (P=0.0002, r=0.50) and peak sputum neutrophil elastase levels (P=0.0006, r=0.47).
Conclusions: PTX3 may be an important mediator of neutrophilic inflammation following RV infection in COPD subjects and smokers. PTX3 is likely to contribute to the inflammatory response in virus-induced COPD exacerbations and may be both a potential biomarker and therapeutic target in COPD.
- © 2011 ERS