Engraftment Kinetics after High-Dose Chemotherapy and AutologousPeripheral Stem Cell Transplantation

Overview

Background.
Autologous peripheral blood stem cell transplantation (APBSCT) is gradually replacing autologousbone marrow transplantation in many clinical settings. The key question is how to evaluate the quality of grafts. Weanalyzed the relationship between hematopoietic reconstitution and characteristics of patients and grafts.Methods and Results. Data from 95 APBSCTs were analyzed. Peripheral stem cells were obtained aftermobilization using anti-neoplastic chemotherapy followed by Neupogen (G-CSF). After high dose chemotherapyand APBSCT, patients received Leucomax (GM-CSF). Patients were reinfused with a median of 6.1 x 106(range0.83-29.3) CD34+ cells/kg, and 25.1 x l04(range 1.0-167.0) CFU-GM/kg of body weight. The median time toengraftment was 12 days (both for granulocytes 1 x 109/l and platelets 50 x 109/l). We found a significant correlationbetween the number of CD34+ cells and CFU-GM reinfused and also between their respective graft sizes and timeto leukocytes, platelets, and granulocytes recovery. We did not find a significant correlation between the number ofmononuclear cells reinfused and any analyzed parameter (time to engraftment, age, diagnosis, number of previouschemotherapies, type of mobilization or high-dose regimen). However, administration of preparative high-dosechemotherapy consisted of busulphan and cyclophosphamide was associated with the risk of a transient secondarygraft failure.Conclusions. We conclude that the content of progenitors in PBSC grafts and time to booth leukocyte and plateletrecovery are best estimated by the number of CD34+ cells (not less than 1 x 106/kg) and CFU-GM (not less than1 x 104/kg). The number of mononuclear cells in an autologous PBSC graft is not suitable and useful for predictionof engraftment rate. There is probably no additional benefit of reinfusion of more than 8 - 10 x 106CD34+ cells/kgand/or 50 x 104CFU-GM/kg, because hematopoietic recovery is not more rapid.

Key words:
autologous transplantation, peripheral stem cells CD34+, CFU-GM.