GM-CSF increases in vitro the respiratory burst of human neutrophils after liver transplantation

Abstract

Objective: Superoxide production by polymorphonuclear neutrophils (PMNs) under cyclosporin A (CsA) therapy following kidney transplantation is impaired. We investigated if the respiratory burst of PMNs is similarly depressed in patients undergoing CsA treatment following orthotopic liver transplantation (OLTx). Additionally, the in vitro influence of granulocyte-macrophage colony-stimulating factor (GM-CSF) on the superoxide anion production was examined during the respiratory burst. Patients: 10 patients after OLTx and 10 healthy blood donors (control group). Measurements and results: PMNs were stimulated with bacteria (Escherichia coli) or a combination of tumour necrosis factor alpha (TNFα) and N-formyl-methionyl-leucyl-phenylalanine (FMLP). The respiratory burst was measured by oxidation of non-fluorescent dihydrorhodamine to the fluorescent rhodamine by means of flow cytometry. No differences in respiratory bursts from OLTx patients compared to those from healthy blood donors could be seen. Under TNFα/FMLP stimulation, the respiratory burst was significantly increased after in vitro incubation with GM-CSF (500 U ml^–1) in patients following OLTx (from 58.2 to 74.5 %) as well as in the control group (from 47.4 to 61.9 %). Conclusions: Our results demonstrate that superoxide production is not impaired under CsA treatment following OLTx. The respiratory burst of these patients' PMNs can even be augmented by GM-CSF in vitro.