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

Background: Recent studies suggest that T(H)1/T(H)2 and T(C)1/T(C)2 cell imbalances are implicated in asthma pathogenesis. However, the relationship of T-cell profiles to airway inflammation has not been understood. Objective: The purpose of this study was to clarify the correlation between peripheral blood T-cell profiles and airway inflammatory parameters. Methods: Subjects 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-gamma 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. Results: There 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-gamma-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-gamma-producing CD4(+) T cells. No significant difference was found in the proportion of IFN-gamma- 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). Conclusion: These findings indicate a correlation between peripheral blood T(H)2 cytokine production and markers of airway inflammation. Clinical implications: There is an association between immune function and clinical indicators in asthma.