KINETICS OF HEMATOPOIETIC PROGENITOR-CELL RELEASE INDUCED BY G-CSF-ALONE IN CHILDREN WITH SOLID TUMORS AND LEUKEMIAS

The kinetics of peripheral blood progenitor cell (PBPC) release induce d by G-CSF-alone at 10 mu g/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 u nits (CFU-GM) was noted with peak values occurring after the 4th or th e 5th G-CSF dose, Individual values of PBCD34(+) cell levels in patien ts with solid tumors were not significantly different after the 4th an d after the 5th dose. The day-of-collection PBCD34(+) cell concentrati on was related to the harvested CD34(+) cell (P = 0.0001) and CFU-GM n umbers (P = 0.0001), No correlations were found between PBPC enrichmen t and either patient age, body weight, diagnosis or pre-mobilization t reatment duration, The median numbers of 1.1 x 10(6) CD34(+) cells/kg and 28.1 x 10(4) CFU-GM/kg were derived from one patient's blood volum e 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 graf t (2 x 10(6) CD34(+) cell and/or 10 x 10(4) CGU-GM per kg) whether und ertaken after the 4th dose of G-CSF or the 5th.