Airway cytokine expression measured by means of protein array in exhaled breath condensate: Correlation with physiologic properties in asthmatic patients

Within-subject reproducibility of relative cytokine levels. Data are presented as bold vertical bars and whisker plots showing the mean difference and the limit of agreement (±2 SDs of the differences). Differences in the individual relative levels between the first and second EBC samples (n = 5) are superimposed. IL-6sR, IL-6 soluble receptor; sTNF-R, soluble TNF receptor; Mig, monokine induced by IFN-γ; MCP, monocyte chemoattractant protein; G-CSF, granulocyte colony-stimulating factor; M-CSF, macrophage colony-stimulating factor; PDGF, platelet-derived growth factor; TIMP-2, tissue inhibitor of metalloprotease 2; ICAM-1, intercellular adhesion molecule 1.

Relationship between the relative expression level of RANTES and parameters of airflow limitation: A, FEV₁ (percentage of predicted value; r = −0.72, P < 0.01); B, initial Rrs (r = 0.53, P < .05). The lines correspond to the fitted regression equation.

Relationship between airway responsiveness to methacholine (cumulative provocative dose of methacholine causing a 100% increase in Rrs [PD₂₀₀]) and the relative expression levels of TNF-α (r = −0.80, P < .01; A) and TGF-β (r = −0.73, P < 0.01; B). The lines correspond to the fitted regression equation.

Relationship between PEF variability for the week and the relative expression levels of TNF-α (r = 0.75, P < .01; A) and TGF-β (r = 0.66, P < 0.01; B). The lines correspond to the fitted regression equation.