Feasibility of peripheral blood stem cell (PBSC) and peripheral blood mononuclear cell (PBMNC) separation in children with a body weight below 20 KG.

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.