IL-17 mRNA in sputum of asthmatic patients: linking T cell driven inflammation and granulocytic influx?

Respir Res. 2006 Nov 3;7(1):135. doi: 10.1186/1465-9921-7-135.


Background: The role of Th2 cells (producing interleukin (IL-)4, IL-5 and IL-13) in allergic asthma is well-defined. A distinct proinflammatory T cell lineage has recently been identified, called Th17 cells, producing IL-17A, a cytokine that induces CXCL8 (IL-8) and recruits neutrophils. Neutrophilic infiltration in the airways is prominent in severe asthma exacerbations and may contribute to airway gland hypersecretion, bronchial hyper-reactivity and airway wall remodelling in asthma.

Aim: to study the production of IL-17 in asthmatic airways at the mRNA level, and to correlate this with IL-8 mRNA, neutrophilic inflammation and asthma severity.

Methods: We obtained airway cells by sputum induction from healthy individuals (n = 15) and from asthmatic patients (n = 39). Neutrophils were counted on cytospins and IL-17A and IL-8 mRNA expression was quantified by real-time RT-PCR (n = 11 controls and 33 asthmatics).

Results: Sputum IL-17A and IL-8 mRNA levels are significantly elevated in asthma patients compared to healthy controls. IL-17 mRNA levels are significantly correlated with CD3gamma mRNA levels in asthmatic patients and mRNA levels of IL-17A and IL-8 correlated with each other and with sputum neutrophil counts. High sputum IL-8 and IL-17A mRNA levels were also found in moderate-to-severe (persistent) asthmatics on inhaled steroid treatment.

Conclusion: The data suggest that Th17 cell infiltration in asthmatic airways links T cell activity with neutrophilic inflammation in asthma.

Publication types

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

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Asthma / genetics
  • Asthma / immunology*
  • Asthma / pathology*
  • Female
  • Granulocytes / immunology*
  • Humans
  • Interleukin-17 / genetics
  • Interleukin-17 / immunology*
  • Interleukin-8 / immunology*
  • Male
  • Middle Aged
  • RNA, Messenger / genetics
  • Sputum / immunology*
  • T-Lymphocytes / immunology*


  • Interleukin-17
  • Interleukin-8
  • RNA, Messenger