Induced sputum in the management of asthma

Historically, researchers have sought evidence for the presence of airway i nflammation in sputum, Only in the past decade, however, have improvements in the methods of processing sputum turned it into a reliable instrument wi th good measurement properties. The main refinements have been better separ ation of sputum from the remainder of the expectorate of sputum plus saliva , use of dithiothreitol (DTT) to disperse cells, use of cytospins instead o f smears, and measurements of molecular markers of inflammation in the supe rnatant. Results of studies with this methodology have shown sputum to be a valid, repeatable, and evaluative instrument to directly assess airway inf lammation, Because it is noninvasive, this methodology can be applied at ra ndom and repeatedly to determine the characteristics of asthma in different situations and to investigate antiinflammatory properties of drugs in clin ical trials. This review focuses on preliminary evidence of validity of usi ng sputum examination in the management of asthma and other airways disease s. The observations indicate that sputum examination can be useful to docum ent the presence and type of airway inflammation, to predict benefit from c orticosteroid treatment, to monitor the effects of treatment in more severe asthma, and to contribute to the diagnosis of occupational asthma.