Spontaneous apoptosis of neutrophils from healthy humans and patients with severe sepsis. Freshly isolated neutrophils (1 × 10⁶/mL) from healthy volunteers (control; ▪) and patients with severe sepsis (patient; □) were incubated for 16 hours. Neutrophil apoptosis was analyzed by flow cytometry after permeabilization with ethanol and staining with propidium iodide. Data are reported as the percentage of fragmented nuclei reflecting the relative proportion of apoptotic cells. Results represent the mean ± SE of six separate experiments performed with neutrophils from healthy volunteers and patients with sepsis. *P < .05 septic patients versus healthy volunteers.