Correlation of early lymphocyte recovery and progression-free survival after autologous stem-cell transplant in patients with Hodgkin's and non-Hodgkin's Lymphoma

The importance of the association between early lymphocyte recovery and outcome has not been well studied in autologous stem cell transplantation (ASCT). In this retrospective study, we analyzed 90 consecutive patients with non-Hodgkin's and Hodgkin's lymphoma who underwent ASCT. Patients were divided into two groups: group 1 with absolute lymphocyte count (ALC) on day +15 below the median of 667/mm(3), and group 2 with ALC >or=667/mm(3). The median progression-free survival (PFS), but not overall survival (OS), was significantly longer in group 2 when compared to group 1 (16 months vs not reached P=0.02). Group 2 patients also had significantly shorter hospital stay, received higher CD34(+) cell dose, and had shorter time to neutrophil recovery. Multivariate analysis demonstrated day +15 ALC to be an independent prognostic indicator for PFS, but not OS, while CD34(+) cell dose and the number of pretransplant treatments were better predictors for both PFS and OS. We conclude that higher day +15 ALC may independently predict better PFS after ASCT for lymphoma patients; however, whether this merely reflects faster overall recovery caused by higher infused CD34(+) cell dose and less pretransplant therapy needs further investigation.

Poor mobilization of peripheral blood stem cells is a risk factor for worse outcome in lymphoma patients undergoing autologous stem cell transplantation

The effect of poor blood stem cells mobilization on the outcome of autologous stem cell transplantation (ASCT) has not been well studied. Our aim is to evaluate poor mobilization as a prognostic factor in lymphoma patients undergoing ASCT. We analyzed 90 consecutive patients with Hodgkin's (HD) and non-Hodgkin's lymphoma (NHL) who underwent ASCT. Poor mobilization was defined as the inability to obtain > or = 1 x 10(6) CD34+ cells/kg ideal body weight with two large volume aphereses. Patients were divided into 2 groups: group 1 = poor mobilizers, and group 2 = good mobilizers. The poor mobilizers received lower median transplant CD34+ cell dose (2 x 10(6) vs. 4.5 x 10(6)/kg for good mobilizers, P = 0.001), were more heavily pretreated (P = 0.01), and required higher number of aphereses for PBSC collection (P = 0.0006). The median progression-free survival (PFS) in groups 1 and 2 was 10 and 41 months (P = 0.04), while the median overall survival (OS) was 38 months and not reached (P = 0.02), respectively. Univariate analysis showed that > or = 3 pre-transplant treatments, CD34+ cell dose < or = 2 x 10(6), elevated LDH before transplant, and poor mobilization were significant prognostic factors for poor PFS, while only the first three were significant for worse OS. Multivariate analysis using these same four factors revealed that number of pre-transplant treatments (HR = 6.03, P = 0.001), CD34+ cell dose (HR = 0.1, P = 0.0007) were the only independent predictive factors for worse overall outcome. In conclusion, our data show that poor mobilization could indicate poor outcome in lymphoma patients undergoing ASCT, however, it is more likely to be a reflection of the heavy pre-transplant therapy and lower CD34+ cell dose re-infused in this group of patients.

Characterization and outcome of "hard to mobilize"' lymphoma patients undergoing autologous stem cell transplantation

A "hard to mobilize" patient was defined as one in whom >or= 1x10(6) CD 34+ cells/kg cannot be obtained after two consecutive large volume aphereses. Forty-four consecutive Hodgkin's and non-Hodgkin's lymphoma patients who underwent autologous peripheral blood stem cell (PBSC) transplant treatment between June 1996 and June 1998 were included in this study. Twenty-one patients (48%) met the definition of "hard to mobilize" (Group I). All the rest of the patients (n=23) were the good mobilizers (Group II). The initial mobilization protocol for most patients was 10 microg/kg of G-CSF alone for both groups. For Group I, 7/21 (33%) patients were unable to achieve a minimal dose of >or= 1x10(6) CD34+ cells/kg even after a second mobilization attempt and/or bone marrow (BM) harvest (n=5). Overall, 11/21 (52%) required an additional mobilization and/or BM harvest. Only 3/21 (14%) patients were able to meet the target cell dose of >or= 2.5x10(6) CD34+ cells/kg (median of 4 apheresis). In contrast, 87% of Group II achieved the target dose with a median of 2 aphereses. Predictors of poor mobilization were greater than two prior treatment regimens (p=0.038) and the WBC count (<25,000/microL) on the first day of apheresis (p=0.053). Nineteen patients in Group I and all Group II completed treatment with a median time to engraftment of ANC>500/microl of 12 and 11 days, and platelet >20x10(3)/microl of 31 and 13 days, respectively. Outcome analysis revealed that 6/19 patients in Group I died of relapse within one year from transplant compared with only 2/23 of Group II who died of relapse (p=0.005, log rank test). There were no treatment related deaths in either group. Independent predictive features for "hard to mobilize" patients are a lack of significant increase in WBC count on the first day of apheresis and the number of prior treatment regimens. Poor mobilization appears to predict a worse outcome after autografting for lymphoma patients.

The effect of overnight storage of leukapheresis stem cell products on cell viability, recovery, and cost

The cost of harvesting, processing, and freezing multiple peripheral blood stem cell (PBSC) products could easily exceed that of bone marrow harvest. To reduce costs while maintaining product viability, we examined the effect of overnight storage on PBSC products. Sixteen consecutive leukapheresis samples from 12 patients were examined prospectively. Each initial leukapheresis product was stored overnight on ice (median temperature 15 degrees C) after adding an equal amount of M199 culture medium containing heparin. After overnight storage, the product was combined with the next day PBSC harvest if required and processed/frozen per protocols. Parameters measured before and after storage include cell count and differential, viability, bacterial cultures, and colony-forming unit (CFU) assays. The results show that the median cell concentration during storage was 7.12 x 10(7)/ml and the median length of storage was 20 h. After storage, the median viability and nucleated cell recovery were 100% and 99.5%, respectively. In addition, 98% recovery of CFU-GM was achieved. No clotting or bacterial contamination was detected. All 12 patients studied engrafted promptly. In addition, 124 similarly treated patients were retrospectively analyzed. Of these, 48% required > or = 2 large-volume leukaphereses to achieve the target cell dose. As a result of overnight storage, 150 final products, instead of 224, were processed and cryopreserved. This difference is equivalent to 33% cost savings. Again, all patients were transplanted and engrafted successfully. In conclusion, overnight storage and pooling of two consecutive PBSC products are safe, reduce cost, and allow for optimum laboratory staffing.

Measurement of absolute concentration and viability of CD34+ cells in cord blood and cord blood products using fluorescent beads and cyanine nucleic acid dyes

Conventional flow cytometric methods for CD34+ cell counting may be affected by the high number of nucleated red blood cells or nonviable cells in cord blood and its products. We developed a simple flow cytometric no-wash procedure that avoids these shortcomings because it provides absolute CD34+ cell counts and assesses cell viability. Samples were incubated with phycoerythrin (PE)-labeled anti-CD34 (Becton Dickinson Immunocytometry Systems [BD], San Jose, CA) and peridinin chlorophyll protein (PerCP)-labeled anti-CD45 (BD) in bead-containing TRUCOUNT tubes (BD). After red cell lysis with a fixative-free reagent, the impermeant nucleic acid dye YO-PRO-1 (Molecular Probes, Eugene, OR) was added and samples were analyzed on a single-laser FACSCalibur (BD). A comparison with the ProCOUNT progenitor cell assay (BD) in 57 samples revealed excellent correlation of results (r = 0.98, intercept -0.2 cells/microl, slope 1.01). Precision studies conveyed coefficients of variation of 6.4 and 8.9% at concentrations of 35 and 16 CD34+ cells/microl, respectively. In untreated and leukocyte-enriched cord blood 4.5+/-3.8% of CD34+ cells were stained by YO-PRO-1, representing apoptotic or necrotic cells. In post-thawing cryopreserved samples this number increased to 10.4+/-5.5%. Isotype controls showed very low blank values of viable cells (0.1+/-0.4 cells/microl, maximum 2.4) and seemed unnecessary. We found no washing-related alteration of results in 35 samples, indicating that the method may also be performed with cell washing. Replacing YO-PRO-1 with TO-PRO-3 facilitated four-color analysis of subpopulations of viable CD34+ cells on a FACSCalibur equipped with a second (diode) laser. We found the proposed method to be a rapid, efficient, and flexible procedure that improved validity of CD34+ cell counts.