CELLULAR AND BIOCHEMICAL-ANALYSIS OF INDUCED SPUTUM FROM ASTHMATIC AND FROM HEALTHY-SUBJECTS

To determine the feasibility of cellular and biochemical analysis of s putum induced after inhalation of hypertonic (3%) saline, we analyzed sputum induced in 10 healthy and in 18 asthmatic subjects. We also ana lyzed saliva samples from all subjects. The entire sputum sample and t he saliva sample were reduced using dithiotreitol, and cell counts and differentials were determined. Biochemical analysis was performed on sputum and saliva supernatants obtained after centrifugation. We found that induced sputum from asthmatic subjects had a higher percentage o f eosinophils [8.1 +/- 3.43 (mean +/- SEM) versus 0.03 +/- 0.02%, p < 0.009] (after excluding squamous cells) and also had higher levels of albumin (232.3 +/- 54.8 versus 79.5 +/- 9.7 mug/ml, p < 0.02), fibrino gen (44.2 +/- 11.6 versus 11.9 +/- 2.5 mug/ml, p < 0.008) and eosinoph il cationic protein (ECP) (142.6 +/- 34.2 versus 26.1 +/- 4.7 ng/ml, p < 0.006) but not of histamine or tryptase. In saliva, squamous cells made up more than 99% of the cells in both groups, and protein concent rations were not significantly different. We conclude that cellular an d biochemical analysis of induced sputum is feasible in healthy and in asthmatic subjects and that it reveals differences similar to those r eported from analyses of bronchial lavage fluid.