Failure of neutrophil chemotactic function in septic patients

Objective: To investigate the in vitro chemotactic function of neutrophils obtained from patients with sepsis. Design: Prospective study in which purified neutrophils obtained from septic patients and nonseptic control volunteers were assayed for chemotactic function induced by N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP) and leukotriene B-4. The sera nitrate concentrations also were quantified. Setting. University hospital. Patients: Twenty patients with sepsis caused by different infectious foci. Interventions., Routine blood tests, blood or other site cultures, blood collection for neutrophil purification, and sera collection for nitrate assay. Measurements and Main Results: Neutrophils from septic patients exhibited significantly less chemotactic activity than neutrophils obtained from healthy volunteers, in response to FMLP (93.4+/-6.6 vs. 51+/-8.3 migrated neutrophils) and leukotriene B-4 (90.2+/-10 vs. 42.4+/-11.6 migrated neutrophils) stimuli, in a microchemotaxis chamber assay. The impaired chemotaxis occurred mainly in neutrophils from nonsurvivor patients. The extent of neutrophil chemotaxis inhibition (survivor/nonsurvivor) was 33.43%/61.67% and 43.4%/86.98%, in response to FMLP and leukotriene B-4, respectively. Increased serum nitrate (micromoles of NO2 + NO3) concentrations were detected in septic patients, compared with controls, but no differences were found between survivor (91.84+/-14.12) and nonsurvivor (102.6+/-17.36) groups. Conclusions. Septic patients present suppressed neutrophil chemotactic responses to FMLP and leukotriene B-4 Stimuli compared with healthy controls. This is accompanied by increased serum concentrations of nitrate. The impairment of neutrophil chemotaxis was observed mainly in the cells obtained from nonsurvivor patients and may thus be an additional factor contributing to disease outcome.