Autologous transplantation: the viable transplanted CD34+ cell dose measured post-thaw does not predict engraftment kinetics better than the total CD34+ cell dose measured pre-freeze in patients that receive more than 2x10(6) CD34+ cells/kg

BACKGROUND: The aim of the study was to investigate whether the number of viable CD34+ cells in cryopreserved PBPC autografts is a better predictor of engraftment than the total CD34+ cell number determined before freezing. METHODS: A total of 119 patients was treated with autotransplantation for various malignant disorders during the period 1996-2002. All patients were reinfused with at least 2x10(6)/kg total CD34 cells analyzed before programmed freezing in 10% DMSO. The total CD34 cell number determined before freezing was compared with the number of viable cells determined after cryopreservation for 51 of these patients. The number of viable cells was determined by a flow cytometric analysis including triple staining with anti-CD34, anti-CD45 and the viability marker 7-actinomycin D (7-AAD). RESULTS: Simple linear regression analyses showed that both the total transplanted CD34 cell dose measured before freezing and the viable CD34 cell dose determined after cryopreservation were significantly correlated with neutrophil and platelet engraftment. In a multiple regression model the prediction of engraftment was not improved when the transplanted viable CD34 cell dose was included as a variable in addition to the total CD34 cell dose measured immediately after collection. DISCUSSION: Routine estimation of viable CD34 cells after cryopreservation of PBPC autografts is not necessary as long as the total CD34 cell dose is determined before freezing and the patients are reinfused with at least 2x10(6) cells/kg body weight.