Kinetics of Peripheral Blood Stem Cell Collection in Large-Volume Leukapheresis for Pediatric Patients Undergoing Chemotherapy and Adult Patients before Chemotherapy

Abstract

The present study investigated the kinetics involved in collection CD34+ cells and colony-forming units-granulocyte-macrophages (CFU-GMs) during large-volume leukapheresis (LVL) in pediatric patients with malignancies and attempted to correlate the number of cells with the processed blood volume. In addition, adult cases were also examined using the same continuous flow blood cell separator to investigate the difference between children and adults. We examined 5 pediatric patients who had undergone chemotherapy before apheresis and 3 adult patients who were scheduled to undergo chemotherapy following apheresis. Collection was performed using a continuous-flow blood cell separator. Patients received granulocyte-colony-stimulating factor (G-CSF) to mobilize peripheral blood stem cells (PBSCs), except in the case of acute myelocytic leukemia. The processed blood volume was set to approximately 300 ml in children and 500 ml/kg of body weight in adults and the leukapheresis component was collected when approximately 50 ml of blood was processed. Six sequential samples were taken from each component in pediatric patients and 10 sequential samples from adults to obtain CD34+ cells and CFU-GMs. Counts of mononuclear cells (MNCs) and CD34+ cells in peripheral blood were measured just before and after each apheresis. Hemoglobin, hematocrit, and platelet counts in peripheral blood were monitored during apheresis. A total of 11 collections were performed for pediatric patients. The mean total CD34+ cells and CFU-GMs in each fractionated yield did not show a remarkable increase with increasing volume of blood processed. In adults, the kinetics of CD34+ cells in each fractionated yield were determined on a continuous basis and CFU-GMs increased during the course of apheresis. In pediatric patients, circulating MNCs and CD34+ cells were stable during apheresis, whereas in adult patients these cells decreased in the peripheral blood after apheresis. In both pediatric and adult patients, the platelet count in the peripheral blood decreased after apheresis. In contrast to adults, in pediatric patients who had been undergone chemotherapy, the collection efficiency did not appear to increase with increased volume of blood processed. Moreover, there was a marked platelet reduction in peripheral blood following apheresis. We conclude that the kinetics of collecting PBSCs by continuous flow blood cell separator is different between pediatric cases and adults cases. The application of LVL may be prudent in some children with malignancies, including those with a low platelet count and low body weight.

Large volume leukapheresis: Efficacy and safety of processing patient’s total blood volume six times

“…Our results confirm that CD34+ cells were collected at a steady rate throughout the LVL [9,19,26,30]. The lowest CD34+ cell yield and collection efficiency were observed at the very beginning of LVL, which can be explained by the time required to establish interface, and by a dilution effect in the first collection bag, caused by the automated filling with saline [19,29,31].…”

“…The optimal study design would be to compare products collected during the same procedure at different time, which was done in this study, and differences caused by interindividual variability were excluded. Studies of kinetics of PBSC enrichment during LVL showed variable results [3,[8][9][10][19][20][21][22][23][24][25][26][27][28][29][30][31], which could be consequence of difference in volumes of processed blood. Therefore, processed blood volume in our study was standardized and strictly related to the patient's TBV.…”

“…tolerance, and consistence with working hours of apheresis unit, quality control and cell processing laboratories. Time-consuming LVL raises an issue of patient's compliance, but previous studies showed that cooperation for prolonged apheresis procedure could be achieved even in pediatric patients [17,25,26].…”

“…Kinetic study showed that decrease in CD34+ count is related to the number of the TBVs processed. The drop in CD34+ cell count was most evident at the beginning of leukapheresis, as cells were packed into the apheresis device set [3,26]. At the same time, separator draws patient's blood while returns saline which filled set lines, which can cause hemodilution and contribute to CD34+ cell decrease.…”

Kinetics of standardized large volume leukapheresis (LVL) in patients do not show a recruitment phenomenon of peripheral blood progenitor cells (PBPC)

“…19 Finally, a recent study showed different kinetics of PBPC collections during LVL between adults and pediatric patients without increasing time-dependent collection efficiencies for the pediatric patients. 20 However, the hypothesis of recruitment of progenitor cells caused by LVL has never been proved by comparison with a control group. Accordingly, such a recruitment could not finally be demonstrated in humans treated with G-CSF.…”