title: Elevation of IL-6 in the allergic asthmatic airway is independent of inflammation but associates with loss of central airway function.
abstract: 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.
authors.affiliation: Department of Medicine, Division of Immunobiology, University of Vermont, Burlington, Vermont 05405, USA.
authors.forename: Wendy A
authors.initials: WA
authors.lastname: Neveu
authors.forename: Jenna L
authors.initials: JL
authors.lastname: Allard
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Raymond
authors.forename: Lorraine M
authors.initials: LM
authors.lastname: Bourassa
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Burns
authors.forename: Janice Y
authors.initials: JY
authors.lastname: Bunn
authors.forename: Charles G
authors.initials: CG
authors.lastname: Irvin
authors.forename: David A
authors.initials: DA
authors.lastname: Kaminsky
authors.forename: Mercedes
authors.initials: M
authors.lastname: Rincon
mesh_terms: D000328:Adult; D001249:Asthma / Q000276:immunology*; D016207:Cytokines / Q000276:immunology*; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000276:immunology*; D008168:Lung / Q000276:immunology*; D008297:Male; D011014:Pneumonia / Q000150:complications / Q000276:immunology*; D012130:Respiratory Hypersensitivity / Q000276:immunology*
chemical_list: D016207:Cytokines; C508600:IL6 protein, human; D015850:Interleukin-6