title: Effect of inhaled corticosteroids on peripheral blood eosinophil counts and density profiles in asthma.
abstract: BACKGROUND
  Inhaled corticosteroids are effective in the treatment of asthma and reduce bronchial hyperresponsiveness. We examined the effect of inhaled budesonide (1600 micrograms/day for 14 days) on the number and density profile of peripheral blood eosinophils in 10 patients with mild stable asthma in a double-blind, placebo-controlled, crossover trial.
  
  
  METHODS
  At the end of each study period, blood was collected immediately before measurement of bronchial responsiveness calculated as the concentration of methacholine causing a 20% fall in forced expiratory volume in 1 second (PC20). Plasma leukocyte suspension obtained after sedimentation of blood with 46% dextran was layered on a Percoll continuous-density gradient. After centrifugation, 20 sequential aliquots of increasing density gradients were removed for differential counts. Eosinophils recovered from density of gradients less than 1.080 gm/ml were defined as hypodense.
  
  
  RESULTS
  Budesonide treatment resulted in a fall in mean eosinophil count from 0.37 +/- 0.05 x 10(9) L-1 after placebo to 0.16 +/- 0.03 x 10(9) L-1 (p < 0.01). A significant reduction occurred in the hypodense eosinophil population from 51.6% +/- 4.3% after placebo to 38.1% +/- 3.1% after budesonide (p < 0.05). Mean log PC20 increased from -0.26 +/- 0.12 after placebo to -0.004 +/- 0.14 after budesonide (p < 0.01).
  
  
  CONCLUSIONS
  We conclude that inhaled steroid therapy reduces the number of circulating hypodense eosinophils, which is an effect that may underlie the improvement in bronchial hyperresponsiveness.
authors.affiliation: Department of Thoracic Medicine, Royal Brompton National Heart and Lung Hospital, London, United Kingdom.
authors.forename: P M
authors.initials: PM
authors.lastname: Evans
authors.forename: B J
authors.initials: BJ
authors.lastname: O'Connor
authors.forename: R W
authors.initials: RW
authors.lastname: Fuller
authors.forename: P J
authors.initials: PJ
authors.lastname: Barnes
authors.forename: K F
authors.initials: KF
authors.lastname: Chung
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000336:Aerosols; D001249:Asthma / Q000097:blood / Q000188:drug therapy* / Q000473:pathology; D001772:Blood Cell Count / Q000187:drug effects*; D001985:Bronchial Provocation Tests; D019819:Budesonide; D004311:Double-Blind Method; D004804:Eosinophils / Q000187:drug effects / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged; D011282:Pregnenediones / Q000008:administration & dosage* / Q000627:therapeutic use
chemical_list: D000336:Aerosols; D011282:Pregnenediones; D016210:Methacholine Chloride; D019819:Budesonide