Eosinophils in bronchial mucosa of asthmatics after allergen challenge: effect of anti-IgE treatment

Allergy. 2009 Jan;64(1):72-80. doi: 10.1111/j.1398-9995.2008.01881.x. Epub 2008 Dec 12.


Background: Anti-IgE, omalizumab, inhibits the allergen response in patients with asthma. This has not been directly related to changes in inflammatory conditions. We hypothesized that anti-IgE exerts its effects by reducing airway inflammation. To that end, the effect of anti-IgE on allergen-induced inflammation in bronchial biopsies in 25 patients with asthma was investigated in a randomized, double-blind, placebo-controlled study.

Methods: Allergen challenge followed by a bronchoscopy at 24 h was performed at baseline and after 12 weeks of treatment with anti-IgE or placebo. Provocative concentration that causes a 20% fall in forced expiratory volume in 1 s (PC(20)) methacholine and induced sputum was performed at baseline, 8 and 12 weeks of treatment. Changes in the early and late responses to allergen, PC(20), inflammatory cells in biopsies and sputum were assessed.

Results: Both the early and late asthmatic responses were suppressed to 15.3% and 4.7% following anti-IgE treatment as compared with placebo (P < 0.002). This was paralleled by a decrease in eosinophil counts in sputum (4-0.5%) and postallergen biopsies (15-2 cells/0.1 mm(2)) (P < 0.03). Furthermore, biopsy IgE+ cells were significantly reduced between both the groups, whereas high-affinity IgE receptor and CD4+ cells were decreased within the anti-IgE group. There were no significant differences for PC(20) methacholine.

Conclusion: The response to inhaled allergen in asthma is diminished by anti-IgE, which in bronchial mucosa is paralleled by a reduction in eosinophils and a decline in IgE-bearing cells postallergen without changing PC(20) methacholine. This suggests that the benefits of anti-IgE in asthma may be explained by a decrease in eosinophilic inflammation and IgE-bearing cells.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Anti-Asthmatic Agents
  • Antibodies, Anti-Idiotypic
  • Antibodies, Monoclonal / administration & dosage*
  • Antibodies, Monoclonal, Humanized
  • Asthma / drug therapy*
  • Bronchial Provocation Tests
  • CD4-Positive T-Lymphocytes / drug effects
  • Double-Blind Method
  • Eosinophils / drug effects
  • Eosinophils / pathology*
  • Female
  • Humans
  • Immunoglobulin E / immunology
  • Inflammation
  • Male
  • Omalizumab
  • Receptors, IgE / drug effects
  • Treatment Outcome
  • Young Adult


  • Anti-Asthmatic Agents
  • Antibodies, Anti-Idiotypic
  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Humanized
  • Receptors, IgE
  • Omalizumab
  • Immunoglobulin E