Large-volume leukapheresis procedure for peripheral blood progenitor cell collection in children weighing 15 kg or less: efficacy and safety evaluation.

BACKGROUND: We update our experience on large-volume leukapheresis (LVL) in very small patients with malignancies. LVLs were performed with the aim of reducing the psychological impact of leukaphereses by reducing the number of procedures while collecting large numbers of cells. PROCEDURE: Seventeen LVLs were performed using a Cobe Spectra separator in 14 patients weighing < or = 15 kg. A median of 3.8 patient's blood volumes corresponding to 296 mL/kg (range, 202-565) of blood was processed per session of 190 minutes (120-279) duration. A femoral catheter was installed specially for collection for 88% LVL (vs. 35% for standard leukaphereses). A median volume of 16.9 mL/kg was collected with 5.4 x 10(8) MNC/kg (range, 0.6-16.3) and 8.2 x 10(6) CD34+ cells/kg (range, 1.3-31.7). RESULTS: No signs of complications due to citrate toxicity were encountered. No hypotensive or hypothermic episodes were observed. Platelet counts were significantly diminished after each procedure (median: -59%). When the extracorporal line was not primed with red blood cells (RBC), the difference between pre-LVL and post-LVL hemoglobin levels was significant with a median 32 g/L decrease. CONCLUSIONS: The LVL approach for peripheral blood progenitor cells (PBPC) collection in very small children may expose them to the risk of anemia and thrombocytopenia and an excess of special central line installation. The application of this technique in these patients should be reserved for special cases when a very large number of cells must be collected and should be performed by an experienced team.

Safe and efficient peripheral blood stem cell collection in the smallest of children.

To clarify the factors that may affect the peripheral blood stem cell (PBSC) collection in children weighing < or = 15 kg, a consecutive registry of 109 leukapheresis procedures was analyzed. Collections were performed on a COBE Spectra separator. In 65.1% of the procedures, the peripheral vein, together with a central catheter inserted routinely at diagnosis, or 2 peripheral veins were used to access/return. For 84.4% of the procedures, the extracorporeal line was primed with red blood cells. The median granulocyte-macrophage colony forming unit (CFU-GM) number derived from 1 patient's blood volume processed was 13.8 x 10(4)/kg. Six times, a collection series failed, always in children treated for > or = 26 weeks and 4 of those times in children weighing < or = 11 kg. The patient's age, diagnosis, duration of preleukapheresis treatment, and mobilization regimens did not significantly affect the collection yield. Twenty-four transplantations were performed. The median times to neutrophils >0.5 x 10(9)/L and platelets >20 x 10(9)/L were 13 and 20 days, respectively. We conclude that even in very small children, leukapheresis can be performed safely, allowing adequate PBSC collection for transplantation and/or in vitro manipulations.

Feasibility of a PB CD34+ cell transplantation procedure using standard leukapheresis products in very small children.

To evaluate the feasibility and efficacy of CD34+ cell immunoselection from routine peripheral blood stem cell (PBSC) harvests in very small children a prospective study was performed in 15 children with advanced neuroblastoma weighing 20 kg or less. Products of two consecutive leukaphereses carried out on a COBE Spectra separator after G-CSF alone mobilization were pooled for immunoselection on Ceprate column. The median number of CD34+ cells and total CFU-GM collected were respectively 5.9 x 10(6)/kg (range 2.3-23.4) and 126.9 x 10(4)/kg (range 52.9-559.9). After separation the median number of CD34+ cells in the adsorbed fraction was 2.6 x 10(6)/kg (range 1-9.8) with a median purity of 54% (range 21-82) and a median of 95.7-fold (range 35-250) enrichment. Thirteen patients underwent autografts with CD34+ PBSCs after a busulfan 600 mg/m2 + melphalan 180 mg/m2 preparative regimen. The median number of days to achieve an absolute granulocyte count of 0.5 x 10(9)/l and a platelet count of 20 x 10(9)/l were respectively, 12 (range 10-24) and 35 (range 25-43). The median number of platelet transfusions was nine (range 2-15). We conclude that safe and effective immunoselection and transplantation of CD34+ PBSC can be accomplished in children with low body mass.

Successful blood stem cell collection and transplant in children weighing less than 25 kg.

Peripheral blood stem cells (PBSCs) were collected for autotransplantation in 20 children (median age 4 years, range 0.5-10 years) weighing < 25 kg (median 14.5 kg, range 6.8-24 kg) with various malignant diseases: leukemias and lymphomas (n = 6), solid tumours (n = 14). Cytaphereses were carried out after standard chemotherapy (n = 10), mobilizing high-dose chemotherapy (n = 9) or radiotherapy alone (n = 1). In 13 children PBSCs were harvested after haematopoietic growth factor (HGF) administration. PBSCs were collected using a continuous flow blood separator (Cobe Spectra). In 13 patients access was through a central catheter with peripheral venous return, in 4 patients access was through a central catheter with return through a femoral catheter; one patient had femoral catheter access with peripheral venous return and two patients had both access and return through peripheral veins. For 19 patients the extracorporeal line was primed with red blood cells. The median blood flow rate was 13.8 ml/min (range 7-22 ml/min). Sixty-six procedures (mean 3.3/patient, range 1-4) were performed with a mean total collection time of 8.5 h. The median number of granulocyte-macrophage colony-forming units (CFU-GM) collected was 37.7 x 10(4)/kg (mean 107 x 10(4)/kg, range 1.05-882 x 10(4)/kg). The number of CFU-GM collected per procedure in children with HGF was 7.8-fold higher than in children without HGF (median 20.4 versus 2.6 x 10(4) CFU-GM/kg body weight, respectively). There were no consistent effects on peripheral blood counts except on platelet counts which decreased following each procedure (median decrease in platelet count was 36%).(ABSTRACT TRUNCATED AT 250 WORDS)