Correlation between Peripheral Blood T-cell Profiles and Clinical and Inflammatory Parameters in Stable COPD

Background: Recent studies suggest that Tcl/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-γ 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-γ-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-γ-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-γ-producing CD8+ T cells was correlated negatively with single-breath carbon monoxide transfer coefficient (Kco) (ρ = −0.45, p = 0.033) and positively with eNO (ρ = 0.50, p = 0.012). The proportion of IL-4-producing CD8+ T cells was positively correlated with body mass index (ρ = 0.42, p = 0.023) and Kco (ρ = 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