Kinetics of hematopoietic progenitor cell release induced by G-CSF-alone in children with solid tumors and leukemias

Abstract

The kinetics of peripheral blood progenitor cell (PBPC) release induced by G-CSF-alone at 10 μg/kg/day were monitored daily in 42 children with solid tumors and leukemias. Median 16- and 27-fold enrichment of circulating CD34⁺ cells and granulocyte–macrophage colony-forming units (CFU-GM) was noted with peak values occurring after the 4th or the 5th G-CSF dose. Individual values of PBCD34⁺ cell levels in patients with solid tumors were not significantly different after the 4th and after the 5th dose. The day-of-collection PBCD34⁺ cell concentration was related to the harvested CD34⁺ cell (P = 0.0001) and CFU-GM numbers (P = 0.0001). No correlations were found between PBPC enrichment and either patient age, body weight, diagnosis or pre-mobilization treatment duration. The median numbers of 1.1 × 10⁶ CD34⁺ cells/kg and 28.1 × 10⁴ CFU-GM/kg were derived from one patient’s blood volume processed. Nineteen patients received G-CSF-alone primed grafts and had successful engraftment. Our data indicate that in 88% of children a single standard leukapheresis is sufficient to obtain a minimum graft (2 × 10⁶ CD34⁺ cell and/or 10 × 10⁴ CGU-GM per kg) whether undertaken after the 4th dose of G-CSF or the 5th.