<p>Alveolar macrophages from non-smokers or smokers were stimulated for 48h with 10 nM 1,25(OH)<sub>2</sub>D or vehicle. (A) Phagocytosis and (B) oxidative burst by alveolar macrophages from non-smokers (n = 7) and smokers (n = 11) following bacterial challenge. Graphs show the percentage of alveolar macrophages that have internalized <i>E</i>. <i>coli</i> bacteria (A) or have produced reactive oxygen species (B). (C) Cathelicidin levels were measured in supernatants of alveolar macrophage cultures from non-smokers (n = 5) and smokers (n = 5). mean±SEM. *p<0.05, **p<0.01.</p