Chest
Original ResearchCOPDLeukotriene B4 Contributes to Exhaled Breath Condensate and Sputum Neutrophil Chemotaxis in COPD
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Study Design and Subject Characteristics
We recruited 34 stable COPD patients and 24 nonatopic healthy control subjects. Table 1 lists their demographic, functional, and treatment characteristics. All of the COPD patients fulfilled the criteria proposed by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines17 and were ex-smokers. There were 20 subjects with moderate COPD (GOLD stage 2), 13 subjects with severe COPD (GOLD stage 3), and 1 subject with very severe COPD (GOLD stage 4). All COPD patients were in
Airway Neutrophilic Inflammation in COPD
Table 2 lists the characteristics of the sputum cell counts. COPD was clearly characterized by an intense neutrophilic inflammation, as shown by the raised neutrophil counts in the IS sample.
Effect of EBC and Sputum Dilution on NCA
The optimal concentration of EBC and sputum supernatant that was consecutively used in further chemotaxis assays was first determined by performing serial dilutions (1:1, 1:5, 1:10, and 1:50) of the original sample from 14 subjects with COPD and 7 healthy subjects. Both EBC and IS samples contained
Discussion
In this study, we have clearly shown that samples of EBC, as well as of IS, from ex-smoking COPD patients contained raised NCA compared to those of healthy ex-smokers. The EBC NCA was correlated to sputum neutrophil count. Furthermore, by using a specific LTB4 receptor antagonist, LTB4 was found to contribute significantly to the NCA contained in both EBC and sputum.
Both EBC and IS from COPD patients contain active soluble chemoattractants for neutrophils, as demonstrated by the significant
Acknowledgments
Author contributions: Dr. Corhay conducted and realized this study, and wrote the manuscript. Dr. Louis revised the manuscript. Ms. Henket and Ms. Sele conducted all of the in vitro analyses. Drs. Duysinx and Nguyen recruited COPD patients and helped perform the study.
Financial/nonfinancial disclosures: The authors have reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.
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Funding/Support: This study was funded by grants from the Fonds d'investissement de recherche scientifique du Centre Hospitalier Universitaire de Liège and from the Belgian Interuniversity Attraction Poles (IAP P6/38).
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