Neutrophil apoptosis, phagocytosis and oxidative metabolism in septic patients

Objectives

To evaluate neutrophil apoptosis and to determine neutrophil function with use of respiratory burst activity and phagocytosis ability during sepsis.

Setting

Laboratory of Immunology and Hospital São Paulo at Universidade Federal de São Paulo.

Patients

Ten patients with severe sepsis and septic shock, and 10 control healthy volunteers.

Interventions

Blood samples were drawn to evaluate neutrophil apoptosis and neutrophil function by flow cytometry.

Measurements and statistical analysis

Neutrophil apoptosis was assessed by propidium iodide (PI) DNA and annexin V staining. Neutrophil phagocytic capacity in response to Staphylococcus aureus (S. aureus) stimulation was analyzed. Baseline reactive oxygen species formation and in response to phorbol myristate acetate (PMA), N-formyl-methionyl-leucyl-phenylalanine (FMLP), lipopolysaccharide (LPS) and S. aureus stimulation, were assessed by flow cytometry using dichlorofluorescein (DCFH). Differences in extent of apoptosis, phagocytosis and oxidative metabolism in septic patients vs healthy volunteers were analyzed using a Mann–Whitney test.

Results

Neutrophil apoptosis, neutrophil phagocytic ability and reactive oxygen species formation were enhanced in septic patients compared to healthy volunteers.

Conclusions

Circulating neutrophils from septic patients presented increased apoptosis and phagocytic ability. Reactive oxygen species formation was also enhanced in these patients.

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