Altered neutrophil functions in patients with large burns

Neutrophil functions were examined longitudinally in 16 patients with large burns using multiparameter flow cytometry (FCM). At admission and through the first 10 days, the neutrophil expression of surface complement receptors for C3b (CR1) and C3bi (CR3) was increased, whereas neutrophil Fc receptor III (FcRIII) expression decreased. The phagocytosis of C3-opsonized Candida albicans increased during the same time period, whereas the ingestion of Ig-opsonized C. albicans decreased. The neutrophil intracellular killing of C. albicans was reduced by about 25% at admission. The microbicidal capacity was further compromised during the next 2 weeks, with a 50% reduction of intracellular killing 10 days following injury. The kinetics of neutrophil phagolysosomal acidification was altered during the first 20 days after burn injury, as the initial alkalinization of the phagolysosomes documented in control neutrophils could not be demonstrated in patients cells. In addition, patient neutrophil H2O2-production, which was only slightly reduced at admission, was gradually decreased during the first 2 weeks, with an oxidative burst about 40% lower than controls at day 10. All neutrophil functions tested were normal at discharge. The results demonstrate significant metabolic and functional alterations in neutrophils from patients with large burns. The data are consistent with a general activation of circulating neutrophils in the early phase after thermal injury, which is followed by impairment of neutrophil microbicidal mechanisms that may predispose for infectious complications.