Enhanced HPC recruitment in children using LVL and a new automated apheresis system.

Background: A new automated apheresis system has recently been reported as useful in improving peripheral blood HPC collection in adults. The aim of this study has been to verify the utility of this system (AutoPBSC, COBE BCT) for standard leukapheresis and for LVL in the pediatric setting.

Study Design And Methods: A prospective study was set up in 29 leukapheresis procedures carried out in 26 children with malignant diseases and body weight under 40 kg who had undergone mobilization with G-CSF or with G-CSF and chemotherapy. Leukapheresis procedures were performed under two protocols, depending on the total blood volume processed: standard leukapheresis (< or=3) and LVL (>3). The need to prime the tubing set with blood was determined, and the inlet flow rate, collection time, recruitment of CD34+ cells, CD34+ cell collection efficiency, component volume, leukapheresis cell composition, and preapheresis and postapheresis peripheral blood counts were measured. Paired t test, Spearman's correlation coefficient, and the Mann-Whitney U test were employed for statistical analysis.

Results: Because of the low extracorporeal volume (167 mL) of the tubing set of the automated blood processor, priming was necessary in only 2 of 26 patients, both weighing under 10 kg. LVL showed better CD34+ cell yield (7.5 vs. 2.3 x 10(6)/kg; p = 0.047), higher recruitment (2.1 vs. 0.9; p = 0.002), and greater collection efficiency (50% vs. 33%; p = 0.005) than standard leukapheresis. No significant differences were found between groups in collection time. In LVL procedures, CD34+ cell collection efficiency and recruitment were not significantly influenced by the inlet flow rate.

Conclusion: The AutoPBSC is a reliable system for peripheral blood HPC collection in children mainly when used in combination with LVL. The major advantage of this software is a reduced need for priming. LVL allows better CD34+ cell collection efficiency, enhanced recruitment, and improved CD34+ cell yield.