Increased levels of airway neutrophils reduce the inhibitory effects of inhaled glucocorticosteroids on allergen-induced airway eosinophils

Can Respir J. Jan-Feb 2002;9(1):26-32. doi: 10.1155/2002/161969.

Abstract

Background: Treatment with inhaled glucocorticosteroids attenuates allergen-induced airway inflammation but is less effective in people with asthma who have noneosinophilic airway inflammation.

Objective: Studies in which glucocorticosteroid treatment was used before allergen challenges were re-examined to determine whether the efficacy of steroid treatment could be predicted by baseline levels of sputum inflammatory cells.

Patients and methods: Twenty-eight nonsmoking subjects with atopic asthma controlled by beta2-agonists participated in only one of three studies, each carried out with a double-blind, placebo controlled, randomized, crossover design. Subjects were treated with glucocorticosteroids or placebo for six to eight days and then underwent allergen inhalation challenge. Spirometry was measured for 7 h after allergen challenge, and then sputum inflammatory cells were measured. Sputum inflammatory cells were also measured before and after treatment, and 24 h after allergen challenge. The per cent inhibition of the allergen-induced airway responses by glucocorticosteroids was calculated.

Results: Inhaled glucocorticosteroids significantly attenuated the early and late asthmatic responses, and the number of allergen-induced sputum eosinophils (P<0.05). There was a significant negative relationship between the number of sputum neutrophils at baseline, and the per cent inhibition of allergen-induced sputum eosinophils measured at 7 h (r=-0.61, P<0.001) and 24 h (r=-0.73, P<0.0001) after challenge, suggesting that glucocorticosteroids are less effective in attenuating allergen-induced airway inflammation in subjects with high levels of neutrophils. There was no correlation between the number of sputum eosinophils at baseline and the per cent inhibition of allergen-induced responses.

Conclusions: Baseline airway neutrophils, not eosinophils, can be used to predict the efficacy of inhaled steroids on allergen-induced sputum eosinophils.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Inhalation
  • Adult
  • Asthma / drug therapy*
  • Asthma / immunology*
  • Budesonide / administration & dosage
  • Cross-Over Studies
  • Double-Blind Method
  • Eosinophils / immunology*
  • Eosinophils / pathology
  • Forced Expiratory Volume / drug effects
  • Glucocorticoids / administration & dosage*
  • Humans
  • Hypersensitivity, Immediate / drug therapy
  • Hypersensitivity, Immediate / immunology*
  • Leukocyte Count
  • Middle Aged
  • Mometasone Furoate
  • Neutrophils / immunology*
  • Neutrophils / pathology
  • Pregnadienediols / administration & dosage
  • Sputum / cytology*
  • Treatment Outcome

Substances

  • Glucocorticoids
  • Pregnadienediols
  • Mometasone Furoate
  • Budesonide