Abstract
This study examined both the endogenous and exogenous (therapy-related) pharmacokinetics of the cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) in neutropenic children with solid and systemic malignancies. The daily endogenous GM-CSF serum concentration before application was 29 pg/mL. During the 10 days of examination, the concentration rose to an average value of 1351 pg/mL 8 h after application. A significant stimulation of the neutrophils, monocytes, and eosinophils in peripheral blood was documented. No significant correlation between the GM-CSF concentration and peripheral blood cell counts could be documented. Paraclinically, there was no evidence for functional disturbance of either the liver or the kidneys, i.e., under the cytokine therapy. The therapy was well tolerated by all the children involved in the study.