Basic and clinical immunology
Cytokine production by bronchoalveolar lavage T lymphocytes in chronic obstructive pulmonary disease

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Background

T lymphocytes (predominantly CD8+ cells) have previously been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD).

Objective

We sought to describe the profile of cytokine production by CD8+ and CD4+ cells isolated from bronchoalveolar lavage fluid.

Methods

Bronchoalveolar lavage was performed in 11 patients with COPD (median FEV1, 63.3% of predicted value) and 9 healthy control subjects. CD8+ and CD4+ T cells were isolated by means of positive selection after macrophage depletion. CD8+ and CD4+ cells were activated with anti-CD3/CD28 antibodies for 60 hours before restimulation with phorbol 12-myristate 13-acetate–ionomycin and brefeldin. Three-color flow cytometry was used to simultaneously measure levels of intracellular cytokines.

Results

IL-4 was expressed by a higher percentage of stimulated CD8+ T cells (TC2) compared with CD4+ T cells (TH2) in patients with COPD (P = .01). In contrast, IFN-γ was expressed in a significantly higher percentage of stimulated CD4+ T cells (TH1) than CD8+ T cells (TC1) in the COPD group (P = .04). TNF-α was expressed by almost all TC1 and TH1 cells, with virtually no expression by TC2 and TH2 cells. In addition, a small number of T cells expressing TNF-α alone without concomitant IFN-γ or IL-4 expression were seen in the majority of subjects. There was a higher percentage of TC2 cells in subjects with COPD compared with that seen in the control group (P = .03). Stimulation with anti-CD3/CD28 antibodies increased the percentage of TC2 cells and decreased the percentage of TH2 cells.

Conclusion

Our results suggest that there are increased numbers of TC2-like cytokine-expressing cells in the lungs of patients with COPD.

Clinical implications

These cells might be a source of TH2 cytokines, which might, at least in part, explain the lung eosinophilia associated with COPD exacerbations.

Section snippets

Subjects

The study protocol was approved by the ethics committees of the Silesian Medical Academy and The Royal Brompton and Harefield Hospital. All subjects provided written informed consent before entering the study.

Eleven patients with moderate stable COPD (7 male and 4 female patients) were recruited for the BAL study, and 4 patients were recruited for the blood study. The inclusion criteria were as follows: FEV1/forced vital capacity ratio of less than 70%, FEV1 of less than 85% of predicted value,

Patient and BAL cell characterization

The total and differential BAL cell counts obtained from the 2 subject groups are shown in Table II. Recovery of BAL fluid was significantly lower in patients with COPD compared with that seen in control subjects, although the total number of cells recovered was no different between the 2 groups. The number of CD8+ (median, 0.8 × 105; range, 0.3-21.5 × 105) and CD4+ (median, 1.28 × 105; range, 0.15-10 × 105) T cells isolated from all subjects was similar. The number of CD8+ (P = .01), but not

Discussion

In this study we demonstrate the profile of cytokine production by CD8+ and CD4+ T cells isolated from the BAL fluid of patients with COPD for the first time. IL-4 was expressed by a higher percentage of stimulated CD8+ T cells compared with CD4+ T cells in patients with COPD. In contrast, IFN-γ was expressed in a significantly higher percentage of stimulated CD4+ T cells (TH1) than CD8+ T cells (TC1) in the COPD group. TNF-α was expressed by almost all IFN-γ+ cells (TC1 and TH1 cells), with

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  • Cited by (0)

    Supported by a research grant from GlaxoSmithKline (UK). AB was an ERS and Polish Foundation of Science Fellow.

    Disclosure of potential conflict of interest: O. Kon is on advisory panels for GlaxoSmithKline and AstraZeneca. The rest of the authors have declared that they have no conflict of interest.

    Dr Barczyk is currently affiliated with the Department of Pneumology, Silesian Medical Academy, Katowice, Poland.

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