Changes in sputum composition during sputum induction in healthy and asthmatic subjects.
BACKGROUND
Induced sputum is increasingly used to characterize the cellular and biochemical composition of the airways.


OBJECTIVE
We studied whether the composition of induced sputum is different between samples obtained sequentially during one sputum induction.


METHODS
Subjects with mild asthma (n=7) or healthy subjects (n=6) produced sputum during and after three consecutive 10 min periods of hypertonic saline inhalation. Samples were analysed separately for the three periods. To determine the reproducibility of the cellular composition, sputum induction was repeated on another two days.


RESULTS
The mean percentage of neutrophils decreased significantly (P<0.01) during sputum induction in asthmatic (36.9, 29.8, 16.3%) and healthy subjects (43.6, 17.2, 18.0%). Correspondingly, percentages of macrophages increased and percentages of eosinophils were 4.9, 3.5, and 3.7% in the asthmatic and 0.6, 0.7, and 0.5% in the healthy subjects, without significant change over the three periods; mean eosinophil numbers were significantly higher in the subjects with asthma (P< 0.05). Reproducibility of percentage cell counts did not markedly depend on sampling periods in terms of coefficients of variation. The concentration of eosinophil cationic protein decreased in both groups during sputum induction (P<0.01), geometric mean values being 579, 143, 57.4 microg L(-1) in the asthmatic and 130, 47.3, 28.4 microg L(-1) in the healthy subjects. Similar changes were seen for lactate dehydrogenase.


CONCLUSIONS
The separate analysis of induced sputum from three consecutive sampling periods of a single induction procedure demonstrated significant changes in their cellular and biochemical composition, both in healthy and mild asthmatic subjects.
Holz
O
O
Krankenhaus Grosshansdorf, Zentrum für Pneumologie und Thoraxchirurgie, LVA Freie und Hansestadt Hamburg, Germany.
Jörres
R A
RA
Koschyk
S
S
Speckin
P
P
Welker
L
L
Magnussen
H
H
D000280:Administration, Inhalation; D000328:Adult; D001249:Asthma / Q000503:physiopathology*; D001798:Blood Proteins / Q000032:analysis; D002452:Cell Count / Q000379:methods; D047091:Eosinophil Granule Proteins; D004804:Eosinophils; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D018836:Inflammation Mediators / Q000032:analysis; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D016676:Macrophages, Alveolar; D008297:Male; D009504:Neutrophils; D015203:Reproducibility of Results; D012260:Ribonucleases; D012462:Saline Solution, Hypertonic; D013183:Sputum / Q000737:chemistry* / Q000166:cytology*; D014797:Vital Capacity
D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; D018836:Inflammation Mediators; D012462:Saline Solution, Hypertonic; D007770:L-Lactate Dehydrogenase; D012260:Ribonucleases