Background: Recent studies suggest that Tc1/Tc2 imbalances are implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). The purpose of this study was to clarify the relationship between peripheral blood T-cell profiles and pulmonary function or inflammatory parameters.
Methods: Thirty-one patients with stable COPD (median age 70 years, 30 males, 15 current smokers and 16 ex-smokers) and 30 healthy control subjects were enrolled in this study. The subjects underwent blood tests, exhaled nitric oxide (eNO) measurement, pulmonary function tests, and sputum induction. Tc1/Tc2 and Th1/Th2 were determined by analyzing intracellular cytokine staining for IFN-gamma and IL-4 in peripheral blood CD8+ and CD4+ T cells using flow cytometry after stimulation with phorbol 12-myristate 13-acetate and ionomycin.
Results: There was a significantly increased proportion of IFN-gamma-producing and IL-4-producing CD8+ T cells in patients with COPD compared with control subjects (median [IQR] 73.6% [63.9%-80.7%] vs 62.0% [45.6%-73.8%], p=0.004; and 2.6% [1.1%-6.9%] vs 1.1% [0.6%-2.2%], p=0.002, respectively). In addition, the proportion of IFN-gamma-producing CD4+ T cells was significantly higher in patients with COPD compared with control subjects (25.7% [21.2%-38.0%] vs 22.8% [15.6%-29.2%], p=0.027). The proportion of IFN-gamma-producing CD8+ T cells was correlated negatively with single-breath carbon monoxide transfer coefficient (Kco)(rho=-0.45, p=0.033) and positively with eNO (rho=0.50, p=0.012). The proportion of IL-4-producing CD8+ T cells was positively correlated with body mass index (rho=0.42, p=0.023) and Kco (rho=0.47, p=0.026).
Conclusions: It is suggested that Tc1 cells have a detrimental role and that Tc2 cells have a protective role in disease progression.