Correlation between peripheral blood T-cell profiles and airway inflammation in atopic asthma

BackgroundRecent studies suggest that TH1/TH2 and TC1/TC2 cell imbalances are implicated in asthma pathogenesis. However, the relationship of T-cell profiles to airway inflammation has not been understood.ObjectiveThe purpose of this study was to clarify the correlation between peripheral blood T-cell profiles and airway inflammatory parameters.MethodsSubjects included 21 patients with atopic asthma and 20 healthy control subjects. After stimulation with phorbol 12-myristate 13-acetate and ionomycin, flow cytometry was used to analyze intracellular cytokine staining for IFN-γ and IL-4 in peripheral blood CD4+ and CD8+ T cells. Airway inflammation was assessed by using exhaled nitric oxide analysis and induced sputum eosinophil counts.ResultsThere were a significantly increased proportion of IL-4–producing CD4+ T cells (median, 2.7% [interquartile range, 2.4% to 3.3%] vs 1.8% [interquartile range, 1.3% to 2.7%]) and a lower ratio of IFN-γ–producing/IL-4–producing CD4+ T cells (7.3% [interquartile range, 5.8% to 9.5%] vs 10.0% [interquartile range, 8.8% to 13.2%]) in asthmatic patients compared with in healthy subjects (P < .01) but no increase or decrease in the proportion of IFN-γ–producing CD4+ T cells. No significant difference was found in the proportion of IFN-γ– or IL-4–producing CD8+ T cells between the 2 groups. The proportion of IL-4–producing CD4+ T cells was significantly correlated with exhaled nitric oxide (r = 0.48, P < .05) and induced sputum eosinophil counts (r = 0.50, P < .05).ConclusionThese findings indicate a correlation between peripheral blood TH2 cytokine production and markers of airway inflammation.Clinical implicationsThere is an association between immune function and clinical indicators in asthma.