Involvement of IL-9 in the bronchial phenotype of patients with nasal polyposis

Anne Tsicopoulos, Ayako Shimbara, Patricia De Nadai, Oday Aldewachi, Catherine Lamblin, Philippe Lassalle, Andrew F. Walls, Stéphanie Sénéchal, Roy C. Levitt, Jean Darras, Qutayba Hamid, Benoît Wallaert

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


Background: Nasal polyposis (NP) is frequently associated with asthma. In this disease, asymptomatic bronchial hyperresponsiveness (BHR) is thought to precede the development of asthma. IL-9 and its receptor have been reported as candidate genes for asthma and to be associated with BHR. Objective: The objective of this study was to assess the contribution of IL-9 to the pathogenesis of BHR in NP by comparing the expression of IL-9 and its receptor in bronchial biopsy specimens from three groups of patients with NP:NP without BHR, NP with asymptomatic BHR, and NP with BHR and asthma. Methods: Bronchial biopsy specimens were examined in terms of cellular infiltration and in terms of expression of IL-9 protein and mRNA as well as of its receptor by using immunohistochemistry and in situ hybridization. Results: Patients with NP with asthma as compared with the two other groups exhibited an increased bronchial infiltration of basophils, eosinophils, and T cells that correlated with the asthma score. The two groups of patients with NP with BHR showed an increased expression in IL-9 protein and mRNA as well as an increase in the expression of IL-9R mRNA at the epithelial level. These modifications were inversely correlated with the airway responsiveness to methacholine, producing a 20% fall in FEV1. There was a close association between IL-9+ cells, IL-5 mRNA expression, and eosinophil infiltration that correlated with each other. Conclusions: These results suggest an important role for IL-9 in the pathogenesis of BHR and a causal relation between IL-9 and the development of bronchial eosinophilia in asthma.

Original languageEnglish (US)
Pages (from-to)462-469
Number of pages8
JournalJournal of Allergy and Clinical Immunology
Issue number3
StatePublished - Mar 2004
Externally publishedYes


  • Asthma
  • Bronchial biopsy
  • Bronchial hyperresponsiveness
  • Interleukin-9
  • Nasal polyposis

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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