Effect of PMA and GM-CSF on OSM secretion by human PMN. PMN (10⁷/mL) were incubated for 15 minutes without (resting) or with 100 ng/mL PMA or 100 U/mL GM-CSF. Secreted and cell-associated OSM were assayed with a specific ELISA. Results are expressed as the mean ± SEM of four independent experiments. #P < .05 compared with OSM secreted without degranulating agent. *P < .05 compared with cell-associated OSM without degranulating agent. ND, not detected (<2.1 pg/mL).