Colledction of Peripheral Progenitor Cells in Pediatric Patients with Reduced Volume Technique

Abstract

Background: When peripheral progenitor cells (PPC) are harvested in children the special situation of their circulatory system has to be taken into account. Extracorporeal blood volume and product volume should be low to avoid side effects. Setting: Hemapheresis unit and pediatric oncologic ward of a University Clinic. Patients: 12 children with neuroblastoma, Ewing sarcoma, unclassified malignant bone tumor, medulloblastoma, pheochromocytoma, rhabdomyosarcoma and Wilms tumor. Material and Methods: The children underwent 24 PPC collections with a continuous flow system and a reduced volume programme. PPC were mobilized by chemotherapy and G-CSF application. Blood counts and CD34 antigen-expressing cells were determined before apheresis and in the PPC product. PPC were frozen at controlled rates and stored in liquid nitrogen until they were used for autologous transplantation. Results: Except for anticoagulant-induced venous irritation, no adverse side effects were observed. The median product volume was 59 ml (range 34–119 ml) and the yield of CD34 antigen-expressing cells was 1.9 × 10⁶/kg body weight (0.1 × 10⁶– 20.4 × 10⁶/kg). The platelet contamination of the products was 0.25 × 10¹¹(0.05 × 10¹¹–1.43 × 10¹¹). Median hematopoietic reconstitution for platelets was achieved on day 27 after transplantation and for leukocytes on day 10.5, respectively. Conclusion: PPC can be easily collected in children with the reduced product volume technique. The system is adopted to the small blood volume of infants so that no circulatory side effects were observed. The reduced volume technique helps lessening the quantity of dimethylsulfoxide needed for cryopreservation as well as reducing storage space. Platelet contamination of the product was low due to retransfusion of platelet-rich plasma to the patients prior to PPC harvesting.

Collection of peripheral progenitor cells in paediatric patients with a new programme for the collection of mononuclear cells

“…The platelet contamination of the apheresis product was low due to the elutriation principle. A similar low PLT contamination was reported on the reduced volume technique of the AS 104 blood cell separator [11]. Using this technique, platelet-rich plasma was auto- matically pumped back to the children prior to the PPC transfer to the collection container.…”

“…In the Fresenius device, the extracorporeal volume of 220 ml is even lower but the product volume is 240-453 ml in the standard procedure [18,19]. A programme for a reduced product volume with the Fresenius device was used in our Institute without severe side effects over several years [11].…”

“…The present data demonstrate that PPC can be effectively collected in children by the new MNC programme of the Amicus device. Median CD 34+ cell yields were higher than in products collected with the AS 104 machine [11]. Using the continuous-flow CS 3000 blood cell separator with the small volume collection chamber, Worel and co-workers collected a median cell of 7.0 · 10 6 per kg BW (range 1.6-26.5 · 10 6 CD 34+ cells per kg BW) [10].…”

“…PPC collection in small children can lead to haemodynamic problems because of their blood volume. In order to avoid circulatory side effects, special apheresis equipment such as the small volume collection chamber [9,10] and the reduced volume technique [11] have been used to reduce the final product volume. The volume reduction of the product may also be important in lessening the quantity of dimethylsulfoxide needed for cryopreservation, as well as reducing storage space.…”