Peaks of endogenous G-CSF serum concentrations are followed by an increase in respiratory burst activity of granulocytes in patients with septic shock

The relationship between peaks of G-CSF serum concentrations and respiratory burst activity of polymorphonuclear cells (PMN) was investigated in patients with postoperative or post-traumatic severe sepsis and septic shock. Over a 12 month period, a longitudinal analysis of G-CSF, TNF-alpha and IFN-gamma serum concentrations, burst activity of PMN, and expression of CD64 on the surface of PMN, were performed by ELISA technique and flow cytometric analysis, respectively, in 58 patients admitted to the intensive care unit (ICU) on a daily basis until discharge from the ICU or death. Out of these 58 patients, 27 with proven infections were in septic shock for at least 4 days' duration. Seventeen of these patients survived, whereas ten died. In 15 out of these 27 patients, 26 episodes of G-CSF peaks were observed, which were followed in most patients (13/15) by an increase in PMN burst activity, from 28% up to 540% (median 188%). Following the G-CSF peaks, CD64 expression on PMN remained at an increased level, followed by a marked decline 3 days later. TNF-alpha serum concentrations were elevated in most episodes (22/26), whereas IFN-gamma serum concentrations were below the detection level in 23/26 episodes. Taken together, peaks in G-CSF serum concentrations are followed by enhanced CD64 expression and increased burst activity of PMN in most patients with severe sepsis and septic shock. Thus, endogenous G-CSF increases neutrophil function in patients with severe sepsis and septic shock, necessary for resolution of bacterial infections in these patients.