Peaks in G-CSF serum concentrations are accompanied by an increase in phagocytotic activity in most patients with severe sepsis or septic shock

Objectives

To investigate the relationship between endogenous serum concentrations of granulocyte colony stimulating factor (G-CSF) and phagocytotic activity of granulocytes during septic shock in postoperative/post-traumatic patients.

Methods

Over a 6 month period 35 patients with proven infection and severe sepsis or septic shock for at least 3 days' duration were monitored on a daily basis during their stay in the intensive care unit (ICU) until discharge from the ICU or death. In 19 out of these 35 patients one or more peaks in G-CSF serum concentrations occurred. Eleven of these 19 patients survived, eight patients died. A longitudinal analysis of G-CSF serum concentrations, phagocytotic activity of granulocytes and surface expression of monomeric Fc receptor type I (CD64, FcγRI) on granulocytes was performed by ELISA technique (R&D Systems, Minneapolis, MN, USA) and flow cytometry (Phagotest^™; Orpegen, Heidelberg, Germany) and CD64 (clone 22; Immunotech, Krefeld, Germany), respectively on a daily basis.

Results

A G-CSF peak was defined as an increase of at least 30% from one day to the other, followed by a decrease of at least 15% on the next day. The following results are expressed as median (min – max) values. In seven episodes there was a parallel course of the G-CSF peak and phagocytosis with an increase in phagocytosis by 37% (6–50%). In 11 episodes, phagocytosis continuously increased and remained on a higher level after the increase of 10% (1–164%) from day 1 up to day 2. In 10 episodes, there was a decrease by 40% (17–76%) at the day of the G-CSF peak, followed by an increase by 58% (6–322%) on the next day. In 12 episodes, there was no increase (n = 4) or even a decrease (n = 8) by 24% (3–46%) over all days.

Conclusions

A peak in G-CSF serum concentration was followed by a continuous increase in phagocytosis at the same day in 7, and a delayed increase in 21 out of 40 episodes, but no increase or even an decrease in 12 out of 40 episodes. Thus, phagocytotic activity is increased when G-CSF peaks endogenously, in most patients with severe sepsis or septic shock.