Lack of modification of key neutrophil intracellular signaling mechanisms by in vivo administration of rhAPC. Relative phosphorylation of kinases and expression of 5-LO in neutrophils isolated 16 hours after endobronchial LPS-instillation from volunteers who received rhAPC (•) or placebo (○). The ratio of phosphorylated kinase to the total quantity of kinase recovered is plotted. The quantity of 5-LO is relative to the total quantity of p38 MAPK. Solid bars represent the median value for each condition; n = 7 for rhAPC and n = 7 for placebo. Phosphorylation of AKT, p38 MAPK, or ERK (1/2) MAPK, and expression of 5-LO were not significantly modified by the presence or absence of rhAPC, as analyzed by the Wilcoxon unpaired exact test.