Induced sputum is a reproducible method to assess airway inflammation in asthma.
To evaluate the reproducibility of induced sputum analysis, and to estimate the sample size required to obtained reliable results, sputum was induced by hypertonic saline inhalation in 29 asthmatic subjects on two different days. The whole sample method was used for analysis, and inflammatory cells were counted on cytospin slides. Reproducibility, expressed by intra-class correlation coefficients, was good for macrophages (+0.80), neutrophils (+0.85), and eosinophils (+0.87), but not for lymphocytes (+0.15). Detectable differences were 5.5% for macrophages, 0.6% for lymphocytes, 5.2% for neutrophils, and 3.0% for eosinophils. We conclude that analysis of induced sputum is a reproducible method to study airway inflammation in asthma. Sample sizes greater than ours give little improvement in the detectable difference of eosinophil percentages.
Bacci
Elena
E
Cardiothoracic Department, University of Pisa, Italy. ebacci@katamail.com
Cianchetti
Silvana
S
Carnevali
Stefano
S
Bartoli
Maria Laura
ML
Dente
Federico L
FL
Di Franco
Antonella
A
Giannini
Daniele
D
Vagaggini
Barbara
B
Paggiaro
Pier Luigi
PL
D000293:Adolescent; D000328:Adult; D000368:Aged; D001249:Asthma / Q000276:immunology* / Q000473:pathology*; D016535:Bronchial Hyperreactivity / Q000276:immunology / Q000473:pathology; D002452:Cell Count / Q000592:standards; D004804:Eosinophils / Q000473:pathology; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000473:pathology; D008264:Macrophages / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000473:pathology; D015203:Reproducibility of Results; D012462:Saline Solution, Hypertonic; D012463:Saliva; D013183:Sputum / Q000166:cytology / Q000276:immunology*
D012462:Saline Solution, Hypertonic