SWEs induce the production of BLyS by neutrophils: role of G-CSF. Serum samples and SWEs obtained from patients with RA and healthy subjects were preincubated for 2 hours at 37°C in the presence or absence of neutralizing anti–G-CSF or anti–IFN-γ antibodies (5 μg/mL) and were added (at a final 20% vol/vol concentration) to neutrophils (2 × 10⁶/400 μL) isolated from healthy subjects. As control, neutrophils were also incubated with 100 U/mL G-CSF or IFN-γ. Mean ± SEM of cell–associated BLyS to neutrophils cultured for 20 hours are shown (n = 3). ^**Significant inhibitory effects of anti–G-CSF antibodies (P less than .001).