COMPARISON OF LEUKOCYTE COUNTS IN SPUTUM, BRONCHIAL BIOPSIES, AND BRONCHOALVEOLAR LAVAGE

To determine the relationship between inflammatory cells in sputum, br onchoalveolar lavage (BAL), and bronchial mucosa, we counted the numbe r of leukocytes in sputum, BAL, and bronchial biopsies obtained from s ubjects with asthma and with chronic bronchitis in stable condition or during exacerbations. Sputum was induced by inhalation of hypertonic: saline in the asthma group. Spontaneous sputum was collected in the c hronic bronchitis groups. Differential counts of leukocytes were perfo rmed on cytospin preparations of sputum and BAL. Eosinophils, macropha ges, neutrophils, and lymphocytes were quantified in the submucosa of the bronchial biopsies. In asthma and in stable chronic bronchitis, th e percentages of neutrophils were significantly higher in sputum than in BAL whereas the opposite was true of the percentages of macrophages and lymphocytes. The lymphocyte was the predominant cell infiltrating the bronchial submucosa in all groups. BAL eosinophils correlated wit h submucosal and sputum eosinophils in the asthma and exacerbated chro nic bronchitis groups. A similar trend was observed between submucosal and sputum eosinophils. In conclusion, the relative proportion of inf lammatory cells was different in sputum, BAl and bronchial mucosa. How ever, there was a fairly good agreement between the number of eosinoph ils counted with the three techniques in asthmatics and in exacerbated chronic bronchitics, suggesting that sputum cell analysis may be used for a noninvasive assessment of airway eosinophilia.