Figure 1.

Comparisons of percentages of apoptotic neutrophils from healthy controls and COPD patients. Peripheral blood neutrophils were isolated from healthy controls and COPD patients; these groups were sub-divided into those with and without smoking histories. As described in Methods, unstimulated peripheral blood neutrophils were cultured in vitro for 4, 24, or 36 h, after which the percent of apoptotic cells was determined. Results are means ± SEMs for: COPD/smokers (n = 24); COPD/non-smokers (n = 23); Healthy/smokers (n = 24); and Healthy/non-smokers (n = 23). Group comparisons were by Mann–Whitney U test. * significant difference as compared with Healthy/non-smokers (p < 0.05); † significant difference as compared with Healthy/smokers (p < 0.05); ‡ significant difference as compared with COPD/non-smokers (p < 0.05).