Similarly, the same mass concentrations of NOC-E (Figures 1C) and NOC-ED (Figure 1D) increased the release of IL-18 from PBMCs obtained from unstable COPD (Figures 1C,D, black bars) and were almost non-active at inducing IL-18 release from non-smoker- derived (white bars) and smoker-derived (dotted bars) PBMCs (Figures 1C,D). Here, IL18 is linked to chronic obstructive pulmonary disease.