Methods to examine sputum for indices of airway inflammation are evolving. We have examined the repeatability and the validity of an improved method to measure sputum cells and fluid-phase eosinophil cationic protein (ECP), major basic protein (MBP), eosinophil-derived neurotoxin (EDN), albumin, fibrinogen, tryptase, and interleukin-5 (IL-5). Sputum was induced with hypertonic saline twice within 6 d in 10 healthy subjects, 19 stable asthmatics, and 10 smokers with nonobstructive bronchitis. The method included the processing of freshly expectorated sputum separated from saliva, treatment with a fixed proportion of dithiothreitol 0.1% followed by Dulbecco's phosphate-buffered saline, making cytospins, and collecting the supernatant. The reproducibility of measurements, calculated by the intraclass correlation coefficient, was high for all indices measured with the exception of total cell counts and proportion of lymphocytes. Asthmatics, in comparison with healthy subjects and smokers with bronchitis, had a higher proportion of sputum eosinophils (median percent 5.2 versus 0.5 and 0.3), metachromatic cells (0.3 versus 0.07 and 0.08), ECP (1,040 micrograms/L versus 288 and 352), MBP (1,176 micrograms/L versus 304 and 160), and EDN (1,512 micrograms/L versus 448 and 272). Asthmatics differed from healthy subjects, but not from smokers with bronchitis, in the proportion of neutrophils (46.9% versus 24.1%), albumin (704 versus 288 micrograms/mL), and fibrinogen (2,080 versus 440 ng/mL). Smokers with bronchitis showed a trend for a higher neutrophil count and levels of albumin and fibrinogen than healthy subjects. The proportion of sputum eosinophils correlated positively with ECP, MBP, EDN, albumin and fibrinogen levels, and metachromatic cell counts correlated with tryptase. In asthmatics, IL-5 correlated with eosinophil counts. There was a significant negative correlation between sputum indices and expiratory flows and methacholine PC20. Thus, the methods of measuring cell and fluid phase markers in induced sputum used in this study are reproducible and valid. They can therefore be used to reliably measure these indices of airway inflammation.

The role of inhaled corticosteroids in the management of chronic obstructive pulmonary disease (COPD) remains controversial. The purpose of this study was to evaluate whether sputum eosinophilia (defined as eosinophils o3%) predicts clinical benefit from inhaled corticosteroid treatment in patients with smoking-related clinically stable moderate-to-severe COPD.Forty consecutive patients with effort dyspnoea (mean age 67 yrs; 52 pack-yr smoking history; post-bronchodilator forced expiratory volume in one second (FEV1) ,60% predicted, consistent with moderate-to-severe smoking-related chronic airflow limitation) were enrolled. Subjects were treated with inhaled placebo followed by inhaled budesonide (Pulmicort Turbuhaler1 1,600 mg? day -1 ), each given for 4 weeks. While the treatment was single-blind (subject level), sputum cell counts before and after treatment interventions were double-blind, thus removing bias. Outcome variables included spirometry, quality-of-life assessment and 6-min walk test.Sputum eosinophilia was present in 38% of subjects. In these, budesonide treatment normalised the eosinophil counts and, in comparison to placebo treatment, resulted in clinically significant improvement in the dyspnoea domain of the disease-specific chronic respiratory questionnaire (0.8 versus 0.3) and a small but statistically significant improvement in postbronchodilator spirometry (FEV1 100 mL versus 0 mL; p,0.05).In conclusion, sputum eosinophilia predicts short-term clinical benefit from high-dose inhaled corticosteroid treatment in patients with stable moderate-to-severe chronic obstructive pulmonary disease.

The reproducibility of sputum cell counts was examined and the cell counts in patients with asthma were compared with those in patients with chronic bronchitis. Three groups of subjects were studied. Sputum from eight patients with chronic asthma and with sputum production were studied to determine the reproducibility of sputum cell counts. The findings in 10 non-smokers with asthma uncomplicated by other airway disease examined at the time of an exacerbation with sputum (group 2) were compared with those from eight smokers with chronic cough and sputum but no features of asthma (group 3). Sputum plugs were selected by microscopy to ensure their origin from the lower respiratory tract. A total cell count was performed on a trypsinised suspension, and differential and metachromatic cell counts were performed on undiluted plugs. The within specimen and test-retest reproducibility of these measurements was high (reliability coefficient, R, = 0.99 and 0.89). The sputum of the asthmatic patients was characterised by eosinophilia (69%, range 46-92%) and the presence of formaldehyde blockable metachromatic cells (1.5%, range 0.6-2.8%). In comparison, the sputum of the patients with chronic bronchitis had few eosinophils (0.5%) or metachromatic cells (0.14%); the dominant cell type was the macrophage (83%). It is concluded that sputum cell counts are reproducible in the short term, the inflammation of asthma is characterised by eosinophilia and metachromatic cells in sputum, and sputum may provide a useful source of cells for investigating the cellular characteristics of airway inflammation.

The purpose of this study was to examine airway responsiveness, sputum cells and the effects of inhaled corticosteroid in the chronic cough syndrome associated with eosinophilic bronchitis. We studied nine consecutive referrals with chronic cough, sputum with > 10% eosinophils, normal spirometry, and normal methacholine airway responsiveness. Clinical assessment, sputum analysis, allergy skin tests and a methacholine inhalation test were performed at the first visit. Peak expiratory flow (PEF) was measured twice daily for 1 week followed by an adenosine monophosphate (AMP) inhalation test. Subjects were then treated with inhaled beclomethasone 0.4 mg twice daily for 7 days. Sputum analysis and measurement of methacholine responsiveness were then repeated. Excessive airway narrowing to methacholine was not present in any of the subjects. A methacholine plateau response was present in five subjects. Hyperresponsiveness to AMP was absent in six of the nine subjects, and PEF variability was not increased for eight subjects. Corticosteroid therapy led to a reduction in sputum eosinophil counts from 40.1 (SD 21.4)% to 4.0 (4.5)% but there was no significant change in metachromatic cell counts (0.8 SD 0.5% vs 0.6 SD 0.6%) or total cell counts. Methacholine responsiveness improved within the normal range in the three subjects in whom it could be determined. Chronic cough associated with eosinophilic airway inflammation can occur in the absence of variable airflow obstruction (asthma) and can improve after treatment with inhaled corticosteroid. This treatment can reduce the level of methacholine responsiveness within the normal range and reduces sputum eosinophils but not mast cells.(ABSTRACT TRUNCATED AT 250 WORDS)