Effects of prednisolone on eosinophils, IL-5, eosinophil cationic protein,EG2+eosinophils, and nitric oxide metabolites in the sputum of patients with exacerbated asthma

Corticosteroids are considered to be one of the most effective medicine for asthma by suppressing airway inflammation. This study was carried out to i nvestigate the effects of prednisolone in the sputum of exacerbated asthmat ics. Clinical severity, cell differentials, levels of interleukin (IL)-5, e osinophil cationic protein (ECP), EG2+ eosinophils, and nitric oxide (NO) m etabolites were measured. Sputum was examined 2 weeks apart in 13 exacerbat ed asthmatics before and after prednisolone treatment, and once in 12 stabl e asthmatics. We used a sandwich ELISA for IL-5, fluoroimmunoassay for ECP, immunohistochemical staining for EG2+ eosinophils, a NO metabolites assay using modified Griess reaction. Exacerbated asthmatics, in comparison with stable asthmatics, had significantly higher proportion of eosinophils, high er level of ECP, higher percentage of EG2+ eosinophils, and NO metabolites. Exacerbated asthmatics after treatment with prednisolone had reduced the p roportions of eosinophils, reduced level of IL-5, ECP and percentage of EG2 + eosinophils, FEV1 was correlated with the proportion of eosinophils, ECP, and IL-5 respectively. These findings suggest that prednisolone is conside red to be effective medicine for asthma by suppressing eosinophil activatio n through IL-5.