Cytokine production by T-cell clones from bronchoalveolar lavage fluid of patients with asthma and healthy subjects

Cytokines produced by T-lymphocytes play an important regulatory role in inflammation in the airways of asthmatic patients. Our aim was to analyse the cytokine production by T-cell clones from bronchoalveolar lavage fluid (BAL) of patients with allergic asthma and the cytokine production of clones from the patients' peripheral blood (PB), as well as from BAL and blood from healthy controls. In 75 randomly selected CD4+ T-cell clones, we assessed the production of interleukin (IL)-2, IL-4 and interferon-gamma (IFN-gamma). After stimulation with anti-CD3, the clones from the asthmatic patients' BAL (A-BAL) produced significantly more IL-4 and IFN-gamma (median 0.32 and 4.17 ng.mL-1, respectively) than clones from A-PB (0.11 and 1.12 ng.mL-1, respectively). No evidence was found for a dominance of a type 1 or type 2 T-helper cell (Th1- or Th2)-cytokine profile in any of the groups. In three out of nine clones tested, the stimulation with anti-CD2/CD28/phorbol myristate acetate (PMA) induced a shift of the IFN-gamma/IL-4 ratio towards a Th2-type cytokine profile. Our results suggest that the clones from the asthmatic patients' bronchoalveolar lavage were derived from a more differentiated T-cell population. In several clones, the cytokine profile was still modulated by the stimulus applied. Similarly, local conditions in the airways may be involved in directing the cytokine production of T-cells.