title: Peripheral blood progenitor cell collection by large-volume leukapheresis in low-weight children.
abstract: Large-volume leukapheresis (LVL), defined as the processing of at least three blood volumes in a single session for peripheral blood progenitor cell (PBPC) collection, was performed in 32 small children weighing < or = 25 kg, aged 10 months to 8 years, with a variety of malignancies. Harvesting of PBPC was started after 4 days of cytokine (G-CSF, 12 micrograms/kg s.c.) alone. Procedures were performed using a continuous flow blood cell separator (COBE Spectra). The automated program of lymphocytapheresis was modified to achieve a collection rate of 0.9 ml/min. The extracorporeal line was primed with a unit of a packed red blood cells before the procedure. Acid citrate dextrose (ACD) was used as anticoagulant with an ACD inlet ratio of 1:14 and an ACD infusion rate of 1.1 ml/min/L of total blood volume. The inlet flow ranged between 6 and 35 ml/min (median 20 ml/min). A total of 37 apheresis procedures were performed (median 1, range 1-3). In 84% of patients, a single apheresis yields the minimum number of PBPC cells required for transplantation. No consistent side effects were observed, and LVL was well tolerated by children. A median of 7.7 x 10(8) kg MNC, 5.4 x 10(6)/kg CD34+, and 6.2 x 10(4)/kg CFU-GM per apheresis were harvested. Patients with neuroblastoma had a significantly lower yield than other patients. To date, 27 patients have been transplanted after myeloablative treatment, and rapid and sustained engraftment was achieved in all cases. The number of CD34+ cells infused was highly correlated with engraftment kinetics. LVL can be safely and easily performed in small children, allowing adequate PBPC collection for transplantation with rapid hematologic recovery.
authors.affiliation: Department of Pediatric Hematology and Oncology, Hospital Infantil Niño Jesús, Autonomous University of Madrid, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Diaz
authors.forename: A
authors.initials: A
authors.lastname: Alegre
authors.forename: A
authors.initials: A
authors.lastname: Benito
authors.forename: M
authors.initials: M
authors.lastname: Villa
authors.forename: L
authors.initials: L
authors.lastname: Madero
mesh_terms: D001800:Blood Specimen Collection / Q000379:methods*; D001835:Body Weight / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D007223:Infant; D007700:Kinetics; D007937:Leukapheresis; D008297:Male