Effect of plasma and LPS on respiratory burst of neutrophils in septic patients

Abstract

Objective: To compare the respiratory burst of neutrophils in sepsis and control patients using lipopolysaccharide (LPS), autologous plasma, and a combination of the two. Design: Prospective, consecutive case study. Setting: A 16-bed intensive care unit (ICU) in a university teaching hospital. Interventions: None. Patients: Plasma was obtained from 23 healthy patients scheduled for minor surgery immediately prior to induction of anesthesia (controls) and from 23 ICU patients within 24 h of diagnosis of sepsis or septic shock. Measurements and main results: Respiratory burst was determined by lucigenin chemiluminescence expressed as mean ± SEM of peak values of relative light units per neutrophil. There were no significant differences between neutrophils of septic patients and controls for the stimuli saline, phorbol myristate acetate, formyl-methionyl-leucyl-phenylalenine, and LPS alone. Septic patients showed a lower respiratory burst than controls (p < 0.05) under the following stimuli: plasma alone (5911 ± 803 vs 15 397 ± 3038) and LPS and plasma combined (13 857 ± 1537 vs 23 026 ± 2640). However, when stimulated with plasma after priming with LPS, septic patients elicited a higher value than control subjects (11 373 ± 1758 vs 5987 ± 1234, p < 0.05). Conclusions: (1) Some components of the plasma of septic patients may have a profound effect on neutrophil response; (2) plasma as a respiratory burst stimulus differentiates between sepsis and non-sepsis samples better than other common stimuli; (3) precautions must be taken when using plasma together with LPS because of the different response depending on whether LPS-priming precedes the plasma stimulus or both are introduced simultaneously and whether septic or nonseptic plasma is used.