Chest
Original ResearchRepeated Sputum Inductions Induce a Transient Neutrophilic and Eosinophilic Response
Section snippets
Study Design
In a study of the subacute effects of smoking on inflammation,10 we designed a nonsmoking arm that consisted of seven sputum inductions separated by increasing time intervals (0, 3, 6, 12, 24, 48, and 96 h). Healthy subjects refrained from smoking for 9 days before and during the study period, which was verified by measuring the levels of exhaled carbon monoxide (CO) [< 6 ppm] and urinary cotinine (< 25 ng/mL).
Subjects
The 16 participants were > 40 years of age and had normal lung function, as follows:
Subjects
Clinical characteristics of the subjects are listed in Table 1. All subjects successfully refrained from smoking for 9 days before and during the study period. All subjects tolerated the sputum induction procedure well, and no adverse events were reported during the study period.
Sputum Quality
The quality characteristics of the sputum samples are shown in Table 2. Thirty-four of the 112 sputum samples (30%) could not be evaluated for total and differential cell counts, due to the percentage of squamous cells
Discussion
Sputum induction is a tool to monitor airway inflammation, yet some reports have shown a neutrophilic response when it is repeated within 24 to 48 h. This may limit its repeated use in clinical trials. We aimed to investigate both the induction and resolution of inflammation generated by repeated sputum inductions. The main result of our study was that repeated sputum inductions in healthy subjects generate a prolonged increase in the number of sputum eosinophils. This was not accompanied by an
Acknowledgment
The authors thank M.A. Star-Kroezen, A.J. van der Laan-Boers, and E.M.D.H. Swierenga (Lung Function Department) for the many lung function measurements and sputum inductions they performed; I. Sloots, M. van der Toorn, H.A. Buivenga-Steketee, and J.A. Noordhoek (Laboratory of Pulmonology and Allergology) for all measurements in sputum and blood; M.D.W. Barentsen (Laboratory of Pathology) for the counting of the iNOS-positive macrophages on cytospins; and Drs. R.A. Uges and B. Greijdanus
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Cited by (0)
Parts of this study were presented in a poster at the American Thoracic Society 2004 annual meeting.
This study was funded by AstraZeneca, Lund, Sweden.
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.
Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).