Nine children from 10 to 76 months (median 28.0), weighing 8.5 to 19.7 kg (median 13.0 kg) underwent peripheral blood stem cell separation (PBSCS) or peripheral blood mononuclear cell separation (PBMNCS), after insertion of a double-lumen
central venous catheter (8-10 French). Separations were performed with a continuous flow blood separator (Fen-wall CS 3000 plus), running a specially adopted separation-program. In 7 children (5 with
neuroblastoma IV, 1 with multifocal
Ewing's sarcoma, and 1 with
rhabdomyosarcoma IV), stem cells were mobilized by application of
G-CSF at a dosage of 15-27.7 micrograms/kg
body weight (median 16.25) subcutaneously following high-dose
chemotherapy, according to the disease-related protocols, whereas 2 children had PBMNCS to induce graft vs.
leukemia (GvL)-reaction in the HLA-identical sibling suffering from relapsed
chronic myelogenous leukemia (CML: n = 1), or
chronic myelomonocytic leukemia (CMML: n = 1) after allogeneic BMT. In all cases, the collecting procedure was performed after filling the cell separator with priming
solution consisting of 2 U of irradiated and washed packed red cells, 250 ml
human albumin, and
0.9% NaCl. In the 7 patients with solid
tumors between 0.45 and 62.7 x 10(6) CD-34 positive cells/kg
body weight were separated; the patient who had the lowest yield was separated twice after another mobilizing course. Three patients (2 with
neuroblastoma IV and 1 with multifocal
Ewing's-sarcoma) underwent a double
transplantation with 1-3 portions of the collected stem cells within a 5- to 6-week interval. Two children had a rapid engraftment on both peripheral blood stem cell
transplantations (PBSCTs). The third child, who had the lowest yield and was separated twice had prompt engraftment at the first PBSCT but delayed and incomplete engraftment at the second PBSCT. One patient after adoptive immunotransfer with PBMNCs for relapsed CML is now 40 months in complete cytogenetic and molecular
biological remission, whereas the other patient treated for relapsed CMML did not respond to the PBMNC-transfusion. The results indicate that PBSCS and PBMNCS can be performed in children with a
body weight below 20 kg.