[Value of induced sputum in the investigation of asthma].
BACKGROUND
The technique of induced expectoration generates sputum by the inhalation of hypertonic saline. On account of its non-invasive character, its simplicity, its relative harmlessness, its cost effectiveness and its reproducibility this technique, that appeared in the early 1990's, has rapidly established itself as the technique of choice in the investigation of bronchial inflammation in asthma.


BACKGROUND
We present the results of our studies that have contributed to the validation of the technique at the methodological level and to the exploitation of the cellular contents as much as the fluid phase of the expectorations in characterising bronchial inflammation in asthmatics. Our results confirm an infiltration of the airways of asthmatics with eosinophils that appears to be proportional to the severity of the illness. We evaluate the effect of inhaled steroids and of theophylline on sputum eosinophilia and bronchial reactivity and discuss the role of eosinophils on bronchial hyperreactivity. Finally we discuss the use of induced expectoration in clinical practice in asthma.


CONCLUSIONS
The analysis of induced sputum could well become a valuable tool in the clinical evaluation and monitoring of asthma in the same way as symptoms and abnormalities of lung function.


CONCLUSIONS
Induced expectoration has certainly contributed to the understanding of the cellular and molecular mechanisms of asthma as well as the role of bronchial inflammation in the clinical manifestations of the disease.
Louis
R
R
Département de Pneumologie, CHU Sart-Tilman, Université de Liège, Belgique.
Bettiol
J
J
Cataldo
D
D
Bureau
F
F
Seumois
G
G
Radermecker
M
M
Bartsch
P
P
Djukanovic
R
R
D001249:Asthma / Q000145:classification / Q000175:diagnosis* / Q000188:drug therapy / Q000276:immunology; D015415:Biomarkers / Q000032:analysis; D003362:Cost-Benefit Analysis; D004804:Eosinophils / Q000276:immunology; D006801:Humans; D007249:Inflammation; D007958:Leukocyte Count; D015203:Reproducibility of Results; D012462:Saline Solution, Hypertonic; D012720:Severity of Illness Index; D013048:Specimen Handling / Q000191:economics / Q000379:methods* / Q000592:standards; D013183:Sputum / Q000737:chemistry / Q000166:cytology* / Q000276:immunology
D015415:Biomarkers; D012462:Saline Solution, Hypertonic