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

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

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.

IL-4 was expressed by a higher percentage of stimulated CD8⁺ T cells (T_C2) compared with CD4⁺ T cells (T_H2) in patients with COPD (P = .01). In contrast, IFN-γ was expressed in a significantly higher percentage of stimulated CD4⁺ T cells (T_H1) than CD8⁺ T cells (T_C1) in the COPD group (P = .04). TNF-⍺ was expressed by almost all T_C1 and T_H1 cells, with virtually no expression by T_C2 and T_H2 cells. In addition, a small number of T cells expressing TNF-⍺ alone without concomitant IFN-γ or IL-4 expression were seen in the majority of subjects. There was a higher percentage of T_C2 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 T_C2 cells and decreased the percentage of T_H2 cells.

Our results suggest that there are increased numbers of T_C2-like cytokine-expressing cells in the lungs of patients with COPD.

These cells might be a source of T_H2 cytokines, which might, at least in part, explain the lung eosinophilia associated with COPD exacerbations.