Elevation of IL-6 in the allergic asthmatic airway is independent of inflammation but associates with loss of central airway function

Respir Res. 2010 Mar 8;11(1):28. doi: 10.1186/1465-9921-11-28.


Background: Asthma is a chronic inflammatory disease of the airway that is characterized by a Th2-type of immune response with increasing evidence for involvement of Th17 cells. The role of IL-6 in promoting effector T cell subsets suggest that IL-6 may play a functional role in asthma. Classically IL-6 has been viewed as an inflammatory marker, along with TNFalpha and IL-1beta, rather than as regulatory cytokine.

Objective: To investigate the potential relationship between IL-6 and other proinflammatory cytokines, Th2/Th17 cytokines and lung function in allergic asthma, and thus evaluate the potential role of IL-6 in this disease.

Methods: Cytokine levels in induced sputum and lung function were measured in 16 healthy control and 18 mild-moderate allergic asthmatic subjects.

Results: The levels of the proinflammatory biomarkers TNFalpha and IL-1beta were not different between the control and asthmatic group. In contrast, IL-6 levels were specifically elevated in asthmatic subjects compared with healthy controls (p < 0.01). Hierarchical regression analysis in the total study cohort indicates that the relationship between asthma and lung function could be mediated by IL-6. Among Th2 cytokines only IL-13 (p < 0.05) was also elevated in the asthmatic group, and positively correlated with IL-6 levels (rS = 0.53, p < 0.05).

Conclusions: In mild-moderate asthma, IL-6 dissociates from other proinflammatory biomarkers, but correlates with IL-13 levels. Furthermore, IL-6 may contribute to impaired lung function in allergic asthma.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Asthma / immunology*
  • Cytokines / immunology*
  • Female
  • Humans
  • Interleukin-6 / immunology*
  • Lung / immunology*
  • Male
  • Pneumonia / complications
  • Pneumonia / immunology*
  • Respiratory Hypersensitivity / immunology*


  • Cytokines
  • IL6 protein, human
  • Interleukin-6