Cigarette smoke extract induces migration of PMNs in vitro. 2 × 105 freshly isolated PMNs were placed in the top well and the cigarette smoke extract (CSE) was added to the bottom well of a 96-wells Millipore Filtration Plate System. After one hour incubation at 37°C in 5% CO2, the cells from each bottom well were counted. CSE (OD 0.03-0.24) induces migration of PMNs (*, p < 0.05; ***, p < 0.001 CSE vs. control). Legend: each symbol represents a different donor (N = 5, n = 3-9).