In vitro functions of neutrophils induced by treatment with rhG-CSF in severe congenital neutropenia.

Neutrophils (and monocytes) from 5 patients suffering from severe congenital neutropenia (SCN) were investigated in vitro after induction of this cell type by treatment with recombinant human granulocyte colony-stimulating factor (rh G-CSF) in vivo. Some abnormal morphological features were seen, such as anomalies of nuclei of phagocytes. No limitations were found 1) in the ability of neutrophils and monocytes to produce reactive oxygen intermediates (ROI) following stimulation with phorbol-myristate-acetate (PMA), 2) in the ability of neutrophils to phagocytose particles of zymosan A and to produce ROI simultaneously and 3) in the ability to kill bacteria of the species staphylococcus aureus. However the specific migration of neutrophils in a gradient of FMLP under soft agar was decreased to approximately 50% in all patients tested as compared to healthy controls. In addition, spontaneous motility was decreased in one patient. Nevertheless, the good clinical improvements of patients suffering from SCN after treatment with rh G-CSF appeared to be due to induction of neutrophils displaying overall good functional activities with respect to natural defense.