Recombinant granulocyte colony-stimulating factor (G-CSF) is widely used in the treatment of chemotherapy-induced neutropenia as well as in mobilization of peripheral blood stem cells in context with autologous bone marrow transplantation. Beside recombinant non-glycosylated G-CSF expressed in E.coli (Filgrastim) and glycosylated G-CSF expressed in CHO-cells (Lenograstim), pegylated filgrastim (Pegfilgrastim) has been introduced for single-administration into clinical use. Previous studies suggest a different functional activity of glycosylated vs. non-glycosylated G-CSF. Here we study the effects of these different G-CSF on chemotaxis, oxidative burst and antigen expression of granulocytes including and correlated the results with G-CSF serum levels.
Granulocytes were obtained from 27 patients with hematological malignancies before and after the administration of one of the three G-CSFs (10 Lenograstim, 9 Filgrastim, 8 Pegfilgrastim) and isolated using a polymorphprep density gradient. Chemotactic properties were assessed using a Boyden chamber assay in combination with an under agarose assay, both using fMLP as chemotactic stimulus. Release of superoxide anions served as measure of the oxidative burst after stimulation with PMA using a chemiluminescence assay. The viability and surface antigen expression were assessed by FACS. In addition G-CSF serum levels were determined by ELISA.
Patients receiving Filgrastim showed a significantly impaired chemotaxis contrary to patients receiving Lenograstim (p<0.05), in the Pegfilgrastim group patients showed a strong, yet not significant reduction when compared to Lenograstim. No significant effects could be shown in production of superoxide anions in a chemiluminescence assay.
In all three groups, FACS analysis showed a decrease in expression of CD10, CD11b, CD18 and CD62L and a significant increase of the LPS-receptor CD14 as well as an increased expression of the IgG receptor FcγRI (CD64) following G-CSF treatment. The increase of CD64 in the Pegfilgrastim group was significantly stronger compared to the other groups. Moreover, we observed a significantly stronger increase of CD14 in patients receiving Lenograstim when compared to the Filgrastim group. We did not observe significant differences in G-CSF serum levels between the three groups, the highest mean serum concentrations were found in the Pegfilgrastim group.
Our data argue for an improved functionality of granulocytes primed with glycosylated G-CSF.