Comparison of the cryoprotective solutions based on human albumin vs. autologous plasma: its effect on cell recovery, clonogenic potential of peripheral blood hematopoietic progenitor cells and engraftment after autologous transplantation.

BACKGROUND AND OBJECTIVES: Cryopreservation of peripheral blood hematopoietic progenitor/stem cells (PBPCs) requires the addition of cryoprotectant such as DMSO, often prediluted using human serum albumin solution (HSAS). The goal of our study was to verify whether the HSAS may be replaced by autologous plasma (AP) without negative impact on PBPCs quality and engraftment. AP usage is less expensive and allows performing cell preparation in a 'closed system', and hence to reduce the risk of product contamination. MATERIALS AND METHODS: Peripheral blood progenitor cells from 18 patients were divided into two aliquots (500 µl) placed in separate vials, each containing 7·5% DMSO prediluted with 5% HSAS or AP. Post-thaw cell recovery and clonogenic potential was evaluated. During clinical part of the study, the impact of both cryoprotective solution on hematopoietic engraftment was evaluated in two cohorts (n = 26) matched for diagnosis, age and the number of transplanted CD34+ cells. RESULTS: The median recovery of nucleated cells and the number of colony-forming units did not differ between tested cryoprotective mixtures. For AP mixture, neither total protein nor albumin concentration of plasma correlated with cell recovery and clonogenic potential of the PBPCs after cryopreservation. In clinical evaluation, the median time to leucocyte recovery and reconstitution of neutrophils was comparable in both groups: 10 days. We did not observe either significant difference with regard to the time of platelet recovery (median: 15 days for AP vs. 16 for HSAS; P = 0·79). CONCLUSIONS: HSA in cryoprotective mixture may be replaced by AP without negative impact on cell recovery, clonogenic potential or engraftment.

Intermediate-dose Ara-C plus G-CSF for stem cell mobilization in patients with lymphoid malignancies, including predicted poor mobilizers.

The optimal protocol for mobilization of hematopoietic stem cells in patients with lymphoid malignancies has not been determined so far. We retrospectively analyzed the efficacy and safety of Ara-C at a dose of 1.6 g/m(2) compared with CY at a dose of 4.0 g/m(2), both combined with filgrastim. Seventy and forty-five patients, respectively, were included, among whom 60% were defined as 'predicted poor mobilizers'. The use of Ara-C was associated with significantly higher peak number of circulating CD34(+) cells compared with CY (P<0.0001). In the Ara-C group, 95% of patients with multiple myeloma (MM) collected at least 5 × 10(6) CD34(+) cells/kg required for tandem transplantation, and 97% of lymphoma patients collected at least 2 × 10(6) CD34(+) cells/kg, needed for a single autologous hematopoietic SCT (autoHSCT), which was achieved with a single leukapheresis in 91% of cases. Results for the CY group were significantly inferior (P<0.0001). No patient mobilized with Ara-C experienced febrile neutropenia, whereas 35% required platelet transfusions. Among patients who proceeded to autoHSCT, the time of both neutrophil and platelet recovery was significantly shorter for those mobilized with Ara-C than CY. We conclude that intermediate-dose Ara-C+filgrastim is a very effective and relatively safe mobilization protocol for patients with lymphoid malignancies.

The impact of center experience on results of reduced intensity: allogeneic hematopoietic SCT for AML. An analysis from the Acute Leukemia Working Party of the EBMT.

Allogeneic hematopoietic SCT with reduced-intensity conditioning (RIC-HSCT) is increasingly adopted for the treatment of older adults with AML. Our goal was to verify for the first time, if center experience influences outcome of RIC-HSCT. Results of 1413 transplantations from HLA-matched related or unrelated donors for adult patients with AML in first CR were analyzed according to the level of center activity. Transplants were performed in 203 European centers between 2001 and 2007. The 2-year probability of leukemia-free survival (LFS) after RIC-HSCT performed in centers with the lowest activity (< or =15 procedures/7 years) was 43±3% compared with 55±2% in the remainder (P<0.001). The incidence of non-relapse mortality (NRM) was 24±3% and 15±1% (P=0.004), whilst relapse rate was 33±3% and 31±1% (P=0.33), respectively. In a multivariate model, adjusted for other prognostic factors, low RIC-HSCT activity was associated with decreased chance of LFS (hazard ratio (HR)=0.64; P<0.001) and increased risk of NRM (HR=1.47, P=0.04) and relapse (HR=1.41, P=0.01). Center experience is a very important predictor of outcome and should be considered in future analyses evaluating the results of RIC-HSCT. The reasons why centers with low RIC-HSCT activity have worse outcomes should be further investigated.

Impact of different dimethyl sulphoxide concentrations on cell recovery, viability and clonogenic potential of cryopreserved peripheral blood hematopoietic stem and progenitor cells.

BACKGROUND AND OBJECTIVES: The procedure of autologous hematopoietic stem/progenitor cell transplantation requires cryopreservation. Addition of DMSO is necessary to secure the viability of such cells, but this solvent is potentially toxic to stem cells' recipient. 10% DMSO solution is used by the majority of transplant centres. The aim of our study was to test if DMSO concentration might be reduced without negative impact on cell recovery and clonogenicity. MATERIALS AND METHODS: Samples were prospectively collected from 20 patients. Small volumes of leukapheresis products were frozen with different cryoprotective mixtures, containing 10%, 7·5%, 5% and 2·5% DMSO, respectively. The quality of cryoprotective mixtures was evaluated based on recovery, viability and clonogenic potential of hematopoietic stem cells after defreezing. RESULTS: Reduction in DMSO concentration to 7·5% or lower was associated with decreased recovery of nucleated cells. In contrast, the number of colonies was highest for 7·5% DMSO with significant differences when compared to 10% DMSO solution. CONCLUSION: Reduction in DMSO concentration from 10% to 7·5% may have favourable impact on hematopoietic recovery after autologous transplantation. The findings require confirmation in a clinical setting.

Addition of cladribine to induction/consolidation regimen does not impair peripheral blood stem cell mobilization and bone marrow harvest for autotransplantation in acute myeloid leukemia patients.

BACKGROUND: The previous study by the Polish Adult Leukemia Group has demonstrated that addition of cladribine to standard DNR+AraC induction potentiates the antileukemic activity. The goal of this study was to compare the efficacy of bone marrow or peripheral blood hematopoietic cell collection in patients who obtained remission after daunorubicine plus cytarabine induction with cladribine (DAC-7) or without addition of cladribine (DA-7) in preparation for autotransplantation. PATIENTS AND METHODS: Sixty-six patients aged 41 years (range, 17-58 years) were included in this study: 33 cases in the DAC-7 and 33 in the DA-7 arm. Hematopoietic cells were collected from the bone marrow (ABMT, n = 29) or from the peripheral blood (ABCT, n = 37) using cytopheresis after administration of AraC (2 x 2 g/m2) on days 1, 3, 5 and subsequent G-CSF (10 microg/kg) from day 7 as mobilization therapy. RESULTS: The numbers of harvested CD34+ cells were similar in the DAC-7 and DA-7 pretreated patients both after harvesting from peripheral blood (2.55 x 10(6)/kg vs 2.5 x 10(6)/kg) and from bone marrow (1.62 x 10(6)/kg vs 1.55 x 10(6)/kg), respectively. The proportion of patients with sufficient material for autologous bone marrow transplantation was higher in the DAC-7 compared with the DA-7 arm. All patients engrafted; hematopoietic recovery was similar in both subgroups. CONCLUSION: Addition of cladribine to a standard DA induction does not impair the harvesting of hematopoietic cells and their engraftment after autotransplantation.