Fig. 1.

Cytokine production of lymphocyte subsets stimulated using live non-typeable Haemophilus influenzae in control (n = 15) and bronchiectasis (n = 14) subjects. Responses were measured using intracellular cytokine staining and flow cytometry. (a) Cytokine production by cytotoxic T cells. Levels of interferon (IFN)-γ were significantly higher in the control group (*P = 0·023), but levels of other cytokines interleukin (IL)-2, IL-4 and IL-13 were similar in both groups. (b) Cytokine production by natural killer (NK) cells. Levels of IFN-γ were significantly higher in the control group (**P = 0·005), but levels of IL-4 were similar in both groups. (c) Cytokine production by T helper cells. As with the cytotoxic lymphocyte (CTL) and NK cells, the levels of IFN-γ were significantly higher in the control group (*P = 0·025). (d) Example of cytokine staining for IFN-γ and IL-4 in a control subject.