Higher ATG-mediated cytotoxicity by neutrophils after in vivo G-CSF treatment. Neutrophils were derived from healthy volunteers not receiving G-CSF (n = 5) or from donors who received 10 mg/kg G-CSF for at least 5 days (n = 5). (A) Percentage of pHRodo+CTV+ neutrophils as evaluated with flow cytometry; difference between neutrophils with and without G-CSF per ATG concentration tested: 0 μg/mL, P = .005; 1 μg/mL, P = .005; 10 μg/mL, P = .002; 20 μg/mL, P = .005; 100 μg/mL, P = .002. (B) The percentage of neutrophils that phagocytized a target cell as evaluated by confocal microscopy, no G-CSF vs G-CSF: 0 μg/mL 2-hour incubation, P = .99; 20 μg/mL 2-hour incubation, P < .001; 0 μg/mL overnight incubation, P = .90; 20 μg/mL overnight incubation, P = .001. Z-stack analyses were applied to ensure target cells were contained within neutrophils. (C) The geometric mean fluorescent intensity (MFI) of CD11b, CD62L (P = .03), CD66b, CD63 (P = .003), CD64 (P < .001), CD35, and CD16 (P = .03) on neutrophils, with (blue) and without (red) G-CSF treatment. Statistically significant differences (P < .05) are indicated with asterisks.