Morphological features of neutrophil apoptosis. Cytospin preparations of neutrophils from healthy volunteers (A through D) and from patients with severe sepsis (E and F) were treated with TUNEL method after 0 hours (A and E) and 16 hours of incubation (B and F). In addition, neutrophils of healthy humans were incubated with LPS (1 μg/mL) or coincubated with LPS and rhIL-10 (100 U/mL) (C and D). The typical morphologic changes of apoptosis consist of diminution in cell volume and chromatin condensation yielding fragmented or bright homogeneously FITC-stained nuclei. Original magnification of the figures: × 1,000. The figures are representative of five other experiments that yielded the same results.