Blood eosinophil numbers and activity during 24 hours: effects of treatment with budesonide and bambuterol

Abstract

The effects of the inhaled corticosteroid budesonide and the oral long-acting beta-agonist bambuterol on circadian variation of blood eosinophil numbers, serum levels of eosinophil cationic protein (ECP), serum eosinophil chemotactic activity (ECA), and serum neutrophil chemotactic activity (NCA) were studied in two groups of patients with allergic asthma. Group 1 (n = 8) had a circadian variation of peak expiratory flow (PEF) 15% or greater, and group 2 (n = 9) had a circadian PEF variation less than 15%. Both groups were randomized and crossover treated for 4 weeks with (A) 0.4 mg budesonide at 8 AM and 8 PM, (B) 20 mg bambuterol at 8 PM, and (C) placebo. At the end of each period blood eosinophil numbers, ECP, ECA, and NCA were measured during 24 hours at 4-hour intervals. No significant differences in the inflammatory parameters could be observed between the groups, although eosinophil numbers tended to be higher in group 1 than in group 2. Highest eosinophil numbers were observed at night. Budesonide reduced both eosinophil numbers and ECP levels, especially at night; bambuterol had no effect on both variables. No circadian variation or treatment effects were observed for ECA and NCA. This study suggests a role for the eosinophil in the nocturnal worsening of asthma, and it demonstrates that budesonide produces, in contrast to bambuterol, a reduction of (nocturnal) eosinophil numbers and activity.