[The relationship of eosinophil viability enhancing activity in sputum and clinical symptoms in asthma]

We studied the correlation of eosinophil viability enhancing activity (EVEA) in sputum from asthmatic children and clinical symptoms. Sputum from asthmatic children and equal volume of saline were mixed with a Vortex mixer and centrifuged at 40000 G. Clear supernatants were obtained and filtered with 0.22 micron membrane filter. Periphral blood eosinophils purified by Percoll density gradient centrifugation and CD16 negative selection/ immunomagnetic beads technique were incubated with sputum extract for 4 days. Eosinophil viability was examined by staining the cells with fluorescen diacetate and propidium iodide and expressed as eosinophil viability enhancing activity (EVEA). Eosinophil cationic protein (ECP) concentrations in sputum were also measured by a radioimmunoassay. Correlation between EVEA in sputum and pulmonary functions, attack score, treatment score, or sputum ECP was determined by Spearman correlation test. Sputum EVEA was correlated 1) inversely with pulmonary functions on sampling, 2) with attack score of 2 weeks period before sampling, 3) with treatment score of 1 month to 1 week before and 1 to 2 weeks after sampling, and 4) with sputum ECP in individual cases. Sputum EVEA may serve as a suitable parameter for monitoring airway inflammation in asthma.