Predictive factors for peripheral-blood progenitor-cell collections using a single large-volume leukapheresis after cyclophosphamide and granulocyte-macrophage colony-stimulating factor mobilization

Large Volume Leukapheresis for Collecting Hemopoietic Progenitors: Role of CD 34+ Precount in Predicting Successful Collection

In this work we evaluated the efficacy of stem cell collection with Large Volume Procedures. (LVP), and analysed the importance of the CD34+ cell precount in promoting the collection of a sufficient number of CD34+ cells for transplantation, using the Univariate Logistic Regression analysis. Eighty-nine leukapheresis were performed in 49 patients with hematological malignancies and solid tumors, mobilized with chemotherapy plus Granulocyte Colony Stimulating Factor (G-CSF). For each procedure 15.8 liters of blood were processed. The median value of Nucleated Cells (NC) and CD34+ cells precount was respectively 8.29 × 109/ml (range 1.13÷45.4) and 43.08 × 103/ml (range 1.06÷795.2). Results show the capability of LVP to collect large quantities of hemopoietic progenitors with a median CD34+ cell total yield of 215.02 × 106 (range 5.03÷2210). The yields per patients’ body weight were: CD34+ cells 3.23 × 106/kg (range 0.081÷41.58). The regression analysis between blood cell precounts and collection yields gave the following correlations: the CD34+ cell precount correlates with CD34+ yield (r = 0.78 p < 0.00) and with CD34+ cell yield/kg (r = 0.76 p < 0.00). The number of CD34+ cells processed correlated with the number of CD34+ cells collected/kg (r = 0.83 p < 0.000). To investigate the importance of CD 34+ cell precount in promoting CD34+ cell yields ≥2.5 × 106/kg we performed a Univariate Logistic Regression analysis that showed in our patients a probability of collecting ≥2.5 × 106 CD34+/kg that rose from 0.6 to 0.95 for CD 34+ precounts that oscillated from 30 to 40 × 103 CD34+ cells/ml, respectively. The Univariate Logistic Regression gave a probability of collecting ≥2.5 × 106 CD34+ cells/kg that oscillated between 0.64÷0.98 for values of CD34+ cells processed from 6 × 106/kg to 8 × 106/kg, p <0.000. Sixty-three percent of patients reached the target dose of 2.5 × 106 CD34+ cells/kg with only one LVP. Until now 12 patients have been transplanted and all have had a prompt and complete lasting recovery. These results confirm the efficacy of LVP in harvesting hemopoietic progenitors and their ability in reconstituting hemopoiesis of transplanted patients, enabling the estimation of CD34+ precounts and CD34+ cells processed values, highly predictive for the collection of ≥2.5 × 106 CD34+ cells/kg. Furthermore, the Logistic Model suggests that the best strategy to plan a successful CD34+ cell collection procedure is to identify for each patient the amount of CD34+ cells/kg to be processed rather than the fixed processing of 3÷5 blood volumes in all patients.

Large volume leukapheresis is efficient and safe even in small children up to 15 kg body weight

BACKGROUND

The collection of peripheral blood stem cells, although now a routine procedure, is still a challenge in low body weight children because of specific technical and clinical issues. For paediatric patients it is crucial to obtain an adequate number of CD34+ cells with the minimum number of procedures: this can be done using large volume leukapheresis (LVL).

MATERIALS AND METHODS

We analysed the efficacy and safety of 54 autologous LVL performed in 50 children (33 [66%] males and 17 [34%] females), median age 2 years (range, 1-5) and median body weight 12 kg (range, 6-15). The procedures were performed with a COBE Spectra previously primed with red blood cells; ACD-A solution and heparin were used as anticoagulants.

RESULTS

The target CD34+ cell dose (≥5×10/kg body weight) were collected with one LVL in 46 (92%) patients, while four (8%) patients needed another procedure. All our LVL were well tolerated. Side effects were observed in five (9.2%) patients and one procedure had to be discontinued because of catheter-related haemorrhage. The platelet count decreased significantly (p<0.001) after each procedure but without bleeding or need for transfusion support.

DISCUSSION

Our experience confirms that LVL is efficient and safe even in small children, if the procedure is adjusted considering the weight and age of child. The most important factors are good venous access, adequate preparation of the child's electrolyte status, and surroundings in which the small child as well as parents feel comfortable, and can tolerate the procedure better. Although a median platelet loss of 50% can be expected, LVL is safe and reduces the overall number of procedures required. It can be recommended for peripheral blood stem cell collection even in small body weight children with malignant diseases, particularly those who mobilise low numbers of CD34+ cells.

Hematopoietic stem and progenitor cell mobilization in mice

Hematopoietic stem cell transplantation (HSCT) can be performed with hematopoietic stem and progenitor cells (HSPC) acquired directly from bone marrow, from umbilical cord blood or placental tissue, or from the peripheral blood after treatment of the donor with agents that enhance egress of HSPC into the circulation, a process known as "mobilization." Mobilized peripheral blood stem cells (PBSC) have become the predominate hematopoietic graft for HSCT, particularly for autologous transplants. Despite the success of PBSC transplant, many patients and donors do not achieve optimal levels of mobilization. Thus, accurate animal models and basic laboratory investigations are needed to further investigate the mechanisms that lead to PBSC mobilization and define improved or new mobilizing agents and/or strategies to enhance PBSC mobilization and transplant. This chapter outlines assays and techniques for exploration of hematopoietic mobilization using mice as a model organism.

Delayed short-term administration of granulocyte colony-stimulating factor is a good mobilization strategy for harvesting autologous peripheral blood stem cells in pediatric patients with solid tumors

PBSCs have become the preferred source of autologous stem cells for supporting high-dose chemotherapy in childhood solid tumors. The aims of this retrospective study were to examine the optimal timing for administration of G-CSF after chemotherapy and to identify the patients from whom an optimal dose of PBSCs can be harvested. We evaluated the timing of G-CSF administration for harvesting PBSCs in patients with childhood solid tumors. G-CSF was administered immediately after chemotherapy in eight patients (11 harvests, long-term group) and following recovery from hematological nadirs in 17 patients (21 harvests, short-term group). The median duration of G-CSF administration was 22 vs. 5 days, respectively (p < 0.005), and the dose of harvested CD34(+) cells (×10(6) /kg) was 1.4 vs. 2.9, respectively (p = 0.023). Our results suggest that short-term G-CSF administration is a good strategy for harvesting PBSCs in these patients.

Advances in stem cell mobilization

The use of mobilized peripheral blood stem cells (PBSCs) has largely replaced the use of bone marrow as a source of stem cells for both allogeneic and autologous stem cell transplantation. G-CSF with or without chemotherapy is the most commonly used regimen for stem cell mobilization. Some donors or patients, especially the heavily pretreated patients, fail to mobilize the targeted number of stem cells with this regimen. A better understanding of the mechanisms involved in hematopoietic stem cell (HSC) trafficking could lead to the development of newer mobilizing agents and therapeutic approaches. This review will cover the current methods for stem cell mobilization and recent developments in the understanding of the biology of stem cells and the bone marrow microenvironment.

Hematopoietic recovery kinetics predicts for poor CD34+ cell mobilization after cyclophosphamide chemotherapy in multiple myeloma

Autologous stem cell transplantation is an important part of therapy in patients with multiple myeloma. Some patients fail to collect the desired number of stem cells while others require multiple apheresis to reach the desired apheresis target. The aim of this study was to determine the predictive factors and if the hematopoietic kinetics of recovery were predictive for outcome of stem cell mobilization in cyclophosphamide + growth factor (CY-GF) mobilized patients. Three hundred and ninety six consecutive CY-GF mobilization attempts between January 2000 and December 2009 at Mayo Clinic, Rochester, MN were analyzed. Patients were divided into three groups: optimal (>5 × 10(6) CD34/kg), suboptimal (2-5 × 10(6) CD34/kg) and poor (<2 × 10(6) /kg CD34+ cells) mobilization groups. About 86% of patients had optimal stem cell collection, whereas 8% had suboptimal collection and 6% had poor (or failed) collections. Age, Hb, WBC, and platelet levels had an impact on mobilization results. Time to peripheral blood (PB) CD34+cells >10/μL predicted for efficiency of collection and the interval between recovery of WBC>1 post-CY to PB CD34+ cells>10 was shorter in the optimal collection groups. These findings suggest that for patients with a PB CD34+ cell count below 10/μL on Day 13 following CY or 1 day after the WBC>1 × 10(9) /L, addition of plerixafor may be helpful to salvage the mobilization attempt.

[Hematopoietic stem cells mobilization: state of the art in 2011 and perspectives]

High-dose chemotherapy with stem cells support has largely improved in terms of hematopoietic stem and progenitor cells harvest procedures as well as in those, which target or manipulate the cellular composition of autologous graft. Optimal preparative regimens and supportive care had lead to better use of autologous transplantation procedure. For other patients assigned to hematopoietic transplantation, availability of allogeneic donors appears to be an interesting alternative source of hematopoietic stem cells. Since three decades, hematopoietic growth factors development has allowed mobilization optimization and collection of peripheral hematopoietic stem cells leading to reduced days of hospitalization and less blood products requirements, being more cost-effective for patients in autologous transplantation settings and for stem cell collection facilities in allogeneic ones. New perspectives include, besides ex vivo manipulation of graft, development of mobilizing drugs in order to perform transplantation even in poor mobilizers patients. An important goal is achieved with the description of genetic polymorphisms related to optimal mobilization of stem cells. New approach using more promising and selective agents called chemokines, such as plerixafor the main leader among these agents are now available and appear complementary for alternative approach using cytokines alone (G-CSF, GM-CSF, SCF). The aim of this review is to assess the evolution of theses biotechnologies and their role in different steps of autologous transplantation and allogeneic stem cells collection.

Proposed definition of 'poor mobilizer' in lymphoma and multiple myeloma: an analytic hierarchy process by ad hoc working group Gruppo ItalianoTrapianto di Midollo Osseo

Many lymphoma and myeloma patients fail to undergo ASCT owing to poor mobilization. Identification of poor mobilizers (PMs) would provide a tool for early intervention with new mobilization agents. The Gruppo italianoTrapianto di Midollo Osseo working group proposed a definition of PMs applicable to clinical trials and clinical practice. The analytic hierarchy process, a method for group decision making, was used in setting prioritized criteria. Lymphoma or myeloma patients were defined as ‘proven PM' when: (1) after adequate mobilization (G-CSF 10 μg/kg if used alone or ⩾5 μg/kg after chemotherapy) circulating CD34⁺ cell peak is <20/μL up to 6 days after mobilization with G-CSF or up to 20 days after chemotherapy and G-CSF or (2) they yielded <2.0 × 10⁶ CD34⁺ cells per kg in ⩽3 apheresis. Patients were defined as predicted PMs if: (1) they failed a previous collection attempt (not otherwise specified); (2) they previously received extensive radiotherapy or full courses of therapy affecting SC mobilization; and (3) they met two of the following criteria: advanced disease (⩾2 lines of chemotherapy), refractory disease, extensive BM involvement or cellularity <30% at the time of mobilization; age ⩾65 years. This definition of proven and predicted PMs should be validated in clinical trials and common clinical practice.

PBSC harvests individually optimized by using pre-collection CD34(+) values and on-line flow cytometric analysis of the mononuclear cell enrichment

BACKGROUND

We have investigated how the amount of blood processed during collection of PBSC affects the yield of CD34 cells.

METHODS

We first established a method of significantly increasing the enrichment of mononuclear cells (MNC), CD34(+) cells and granulocyte-macrophage progenitors (GM-CFU) by on-line flow cytometric (FCM) analysis of the leukocyte populations in the collect line. A total of 166 PBSC collections from 94 patients, were devided into five groups according to the blood volume processed: < 12 L of processed blood, 12-13L, 13-14L, 14-15L and > 15L.

RESULTS

When the yield of CD34(+) cells war compared between these groups, a positive correlation was seen (r=0.97) between the processed blood volume and the yield, expressed as a ratio between total number of CD34(+) cells in the harvest and the CD34(+) cell concentration in blood. This correlation can be used to estimate the volume that must be processed to exceed a specific target number of CD34(+) cells. The implications of these results on the need for one, two or more leukapheresis procedures in order to collect a sufficient amount of stem and progenitor cells for a given patient are discussed, i n relation to clinical logistics and the benefits for the patients.

DISCUSSION

PBSC harvest can be improved by individually-adjusted leukapheresis according to on-line FCM analysis and pre-harvest levels of CD34(+) cells and the processed blood volume can be used to predict the CD34(+) yield.

Impact of mobilization and remobilization strategies on achieving sufficient stem cell yields for autologous transplantation

The purpose of this article was to examine historic institutional autologous stem cell mobilization practices and evaluate factors influencing mobilization failure and kinetics. In this retrospective study we analyzed clinical records of 1834 patients who underwent stem cell mobilization for autologous transplantation from November 1995 to October 2006 at the Washington University in St. Louis. Successful mobilization was defined as collection of > or =2 x 10(6) CD34(+) cells/kg. From 1834 consecutive patients, 1040 met our inclusion criteria (502 non-Hodgkin's lymphoma [NHL], 137 Hodgkin's lymphoma, and 401 multiple myeloma [MM]). A total of 976 patients received granulocyte colony-stimulating factor (G-CSF) and 64 received G-CSF plus chemotherapy (G/C) for the initial mobilization. Although the median CD34(+) cell yield was higher in G/C group than in G-CSF alone group, the failure rates were similar: 18.8% and 18.6%, respectively. Overall, 53% of patients collected > or =2 x 10(6) CD34(+) cells/kg during the first apheresis with either mobilization regimen. Regardless of mobilization regimen used, MM patients had the highest total CD34(+) cell yield and required less aphereses to collect > or =2 x 10(6) CD34(+) cells/kg. Mobilized, preapheresis, peripheral blood CD34(+) count correlated with first day apheresis yield (r = .877, P < .001) and 20 cells/microL was the minimum threshold needed for a successful day 1 collection. For the remobilization analysis we included patients from the whole database. A total of 269 of 1834 patients underwent remobilization using G/C, G-CSF, and/or GM-CSF, and G-CSF plus plerixafor. Only 23% of remobilized patients achieved > or =2 x 10(6) CD34(+) cells/kg and 29.7% failed to pool sufficient number of stem cells from both collections. Patients receiving G-CSF plus plerixafor had lowest failure rates, P = .03. NHL patients remobilized with G-CSF who waited > or =25 days before remobilization had lower CD34(+) cell yield than those who waited < or =16 days, P = .023. Current mobilization regimens are associated with a substantial failure rate irrespective of underlying disease. Patients who fail initial mobilization are more likely to fail remobilization. These findings suggest that there is a need for more effective first-line mobilization agents.

A randomized comparison of peripheral blood hematopoietic progenitor cell level of 5/mm3 versus 50/mm3 as a surrogate marker to initiate efficient autologous blood stem cell collection

We previously showed that at least 5/mm(3) hematopoietic progenitor cells (HPCs) could be used as a marker for initiating autologous blood stem cell collection (ABSCC). However, the timing of efficient ABSCC following mobilization is still to be determined. We conducted a prospective, randomized comparison of 5/mm(3) versus 50/mm(3) peripheral blood (PB) HPCs as a surrogate marker to initiate efficient ABSCC. Forty-five consecutive patients, 26 with multiple myeloma (MM) and 19 with non-Hodgkin's lymphoma (NHL), were enrolled between October 2004 and October 2006. Chemotherapy was cyclophosphamide 4 g/m(2) for MM and ESHAP (etoposide, methylprednisolone, high-dose cytarabine, and cisplatin), with or without Rituximab, for NHL. Circulating HPCs were monitored daily with the Sysmex SE9000 automated hematology analyzer, and harvested CD34+ cells were counted by flow cytometry. ABSCC was initiated when HPC levels reached at least 5/mm(3) (HPC5 group) or 50/mm(3) (HPC50 group). The median number of harvested CD34+ cells was 15.0 x 10(6)/kg and 21.0 x 10(6)/kg in the HPC5 and HPC50 groups, respectively (P = 0.23). Optimal collection (>5 x 10(6) CD34+ cells/kg) in a single session (day 1) was attained in 15 HPC5 patients (63%) and in 14 HPC50 patients (67%), and targeted collection of 5 x 10(6) CD34+ cells/kg was achieved in 100 and 95% of HPC5 and HPC50 patients, respectively (P = 0.47), with a median number of 1 apheresis in both groups (P = 0.58). There were no between group differences in optimal collection rate on day 1, median number of aphereses to achieve optimal collection, and overall optimal collection rate. HPC > or = 5/mm(3) and > or =50/mm(3) are both reliable indices for the timing of ABSCC.

Optimizing the timing of chemotherapy for mobilizing autologous blood hematopoietic progenitor cells

BACKGROUND

Postchemotherapy mobilization results were reviewed in patients undergoing apheresis before planned autologous hematopoietic progenitor cell (HPC) transplantation to improve the timing of collection procedures.

STUDY DESIGN AND METHODS

A total of 135 attempts to collect autologous HPC were studied in 132 unique patients with lymphoid malignancies (non-Hodgkin's lymphoma, multiple myeloma, and Hodgkin's disease). Chemotherapy mobilization regimens included cyclophosphamide (n = 59), ICE (n = 46), or other regimens (n = 30). Granulocyte-colony-stimulating factor (CSF) was administered once daily at a dose of 5 microg per kg starting 2 days after the last dose of chemotherapy; granulocyte-macrophage-CSF was added at a daily dose of 5 microg per kg 6 days later. Apheresis was initiated when the blood CD34+ content was more than 20 per microL.

RESULTS

In an initial cohort of 37 patients, 27 percent required apheresis during the weekend. An optimized timing for chemotherapy mobilization was developed based on retrospective data; prospective implementation of the new algorithm reduced the incidence of weekend apheresis to 13 percent in the subsequent 98 consecutive patients (p < 0.05). A median of 9 x 10(6) (range, 0.4 x 10(6)-96 x 10(6)) CD34+ cells per kg was collected from the entire cohort of 135 patients after a mean of 1.8 days of apheresis. Apheresis was initiated following a median (+/-SD) of 10 +/- 2.7 days of cytokines.

CONCLUSION

In the majority of patients, the first day of apheresis occurred 11 to 13 days after the last dose of chemotherapy with a variety of different chemotherapy regimens. Administering the last dose of chemotherapy on Thursday or Friday versus Monday, Tuesday, or Wednesday was associated with a 77 percent lower incidence in the frequency of weekend apheresis collections (p < 0.001).

Optimization of CD34+ collection for autologous transplantation using the evolution of peripheral blood cell counts after mobilization with chemotherapy and G-CSF

BACKGROUND

Peripheral blood progenitor cells (PBPC) collection after high dose chemotherapy can be influenced by several factors. We searched for parameters that may predict the best day to start harvesting of PBPC in order to collect most CD34+ cells with the least number of aphereses.

METHODS

We studied patients who underwent mobilization chemotherapy for autologous transplantation. The influence of age, sex, diagnosis, number of previous chemotherapy cycles, peripheral blood (PB) counts at day of mobilization (D0), day of neutrophils <1.0 x 10(9) l(-1) and day of nadir and interval between both (delta) on harvesting was investigated. Multivariate linear correlation models were built to predict the best harvesting with principles of parsimony. In patients where sequential CD34+ cell count was performed, the theoretical day of peak was calculated by interpolation in polynomial regression.

RESULTS

One hundred and thirty four patients entered the analysis: 36 Hodgkin's lymphoma (HL), 65 B-large cell lymphoma (NHL) and 33 multiple myeloma (MM). Day of harvesting correlated with nr CHT, hemoglobin on D0, day of granulocytes <1.0 x 10(9) l(-1), delta and dosis of mobilization therapy. The day of CD34+ peak could be calculated by the formula = (-0.41) x Hemoglobin D0 + (day peripheral CD34+ cells = 10 x 10(6) microl(-1)) x 0.99 + 7.8. This model could explain 81% of the variance of the peak day and was stable by bootstrap resampling. Day of peripheral CD34+ cells = 10 x 10(6) microl(-1) preceded the calculated peak by 3-9 days.

CONCLUSIONS

Although the day of best collection can be predicted using only sequential PB counts after mobilization chemotherapy, a model of prediction using peripheral CD34+ cell count is important especially for optimizing collection in poor mobilizing patients.

Comparison of flow cytometry vs. a haematology cell analyser-based method to guide the optimal time-point for peripheral blood stem cell apheresis

BACKGROUND AND OBJECTIVES

For timing the onset of apheresis, parameters obtained by flow cytometry and by a haematological cell analyser were compared.

MATERIALS AND METHODS

Haematopoietic cell counts (n = 159) were performed by two different methods; CD34 analyses by flow cytometry, immature myeloid information (IMI) and human progenitor cell counts (HPC) by a haematological cell analyser.

RESULTS

Comparing the IMI total results with CD34+ analyses (n = 159) revealed a correlation of r = 0.46 (P < 0.05). Similar results were obtained for HPC (r = 0.44; P < 0.05).

CONCLUSION

The haematology analyser-based method does not allow the precise determination of absolute haematopoietic stem cell numbers and is thus not able to replace flow cytometry for the monitoring of peripheral blood stem cell counts.

Autologous peripheral blood stem cell collections in children weighing less than 10 Kg with solid tumors: Experience of a single center

There have only been a few reports and limited performance of peripheral blood stem cell (PBSC) collection in very small children weighing less than 10 kg. In this study, we intended to evaluate the safety and yield of PBSC collection, with the efficacy of PBSC transplantation (PBSCT) in the smallest children with solid tumors. From January 1998 to February 2004, 173 children underwent PBSC collection in Samsung Medical Center, Korea. Of these, 15 (8.7%) children weighed less than 10 kg and their clinical diagnoses were neuroblastoma (10 cases), rhabdoid tumor (2 cases), rhabdomyosarcoma (2 cases), and Wilms tumor (1 case). PBSCs were collected following chemotherapy plus G-CSF mobilization. The median age and weight at the time of apheresis were 15 months and 9 kg, respectively. The median number of PBSC collection procedures per case was 4 (range, 2-7). The median cell yield per apheresis product was 0.95 (range, 0.01-33.32) x 10(6)/kg CD34+ cells and 1.96 (range, 0.12-23.39) x 10(8)/kg mononuclear cells. No complications associated with citrate toxicity and other adverse effect were observed during the procedures. After high-dose chemotherapy, 14 patients were reinfused with PBSCs alone and all showed successful hematopoietic recovery. We concluded that PBSC collection would be a safe and practical procedure, even when done in the smallest children, provided that adequate intravascular fluid volume and circulating red cell mass were maintained. Also, the use of PBSCs to support high-dose chemotherapy was well tolerated and might enhance hematological recovery in the smallest children showing the excellent efficacy of PBSCT.

Initiation of peripheral blood progenitor cell harvest based on peripheral blood hematopoietic progenitor cell counts enumerated by the Sysmex SE9000

BACKGROUND

The most reliable index for timing peripheral blood progenitor cell (PBPC) collection following mobilization is still to be determined. The techniques to enumerate peripheral blood (PB) CD34+ cells are expensive and time-consuming. The SE9000 (Sysmex) provides an estimate of immature cells, called hematopoietic progenitor cells (HPCs). The aim of this study was to prospectively evaluate the efficacy of PB HPC levels for timing PBPC harvest.

STUDY DESIGN AND METHODS

Thirty-five patients (15 non-Hodgkin's lymphoma and 20 multiple myeloma) were enrolled. PB HPCs and harvested CD34+ cells were counted with the SE9000 and flow cytometry, respectively. Circulating HPCs were monitored daily. PBPC harvest was initiated when HPC levels reached at least 5 per mm(3).

RESULTS

HPC levels reached 5 per mm(3) or more on Median Day 12 (range, days 9 to 16) of mobilizing chemotherapy. The median number of CD34+ cells collected per patient was 19.40 x 10(6) per kg (range, 1.94 x 10(6)-52.55 x 10(6) per kg). Both successful and optimal harvest was achieved in 97 percent of patients. PBPCs were successfully harvested in 25 patients (71%) in one session. An optimal harvest in a single session was attained in 16 patients (46%).

CONCLUSION

This might be the first prospective study showing the PB HPC level for timing PBPC harvest.

Improving the efficiency of PBPC collection by pre-apheresis peripheral blood and mid-apheresis product measurements of CD34 cells

BACKGROUND

The adequacy of HPC collection for BMT is typically assessed by the number of CD34 cells. However, during a series of leukapheresis procedures (LP) the CD34 value on the final HPC product may not be available for testing until late evening, sometimes resulting in additional, retrospectively unnecessary, LP in order to ensure an adequate HPC collection (>5x10(6) CD34/kg). We hypothesized that an estimate of the CD34 content of HPC products prior to 16:00 h on the day of LP would permit improved HPC collection planning. We therefore assessed the effectiveness of predicting the total amount of CD34 cells that would be collected in a given LP by either (a) the concentration of CD34 cells/microL in peripheral blood prior to LP (pre-CD34) or (b) the predicted total amount of CD34 cells to be collected based on sampling the LP product at the mid-point of each LP. We also compared the number of LP per patient and total HPC collected for the study group with data from the previous calendar year.

METHODS

Allogeneic and autologous BMT donors who completed a 20-L HPC collection between September 2002 and February 2003 were eligible. CD34 cells were measured on blood drawn prior to LP and from the HPC product at the mid-point (10 L) of LP. The CD34 content of the final LP was predicted by doubling the value of total CD34 cells at the mid-run (MRp-CD34). The MRp-CD34/kg and the cumulative CD34/kg collected were made available before 16:00 h and used to determine the need for additional LP. The true CD34 content of each HPC collection was also measured from the final product the next day (CD34-FP).

RESULTS

A 20-L LP was completed and data were available from 31 patients and nine allogeneic donors who underwent a total of 85 LP for diagnoses, including 11 myeloma, 10 lymphoma, seven HD, three acute leukemia and five others. The mean (range) and correlation (R2) vs. the CD34-FP were, for pre-CD34, 54 CD34/microL (0.3-232), R2=0.66 (P<0.01), and for MRp-CD34, 3.2x10(6) CD34/kg (0.04-22.48), R2=0.90 (P<0.01). The mean number of CD34/kg collected per LP in the patients/donors was 3.4x10(6) CD34/kg (0.05-18.94). The median number of CD34 cells employed for transplant in the study group vs. controls (5.7 vs. 5.6x10(6)/kg) and the time to engraftment of neutrophils (12 vs. 11 days) and platelets (12 vs. 12 days) was similar to historical controls. However, the study group had a significantly lower median number of LP (three vs. two; P<0.02) to obtain the required collection of 5x10(6) CD34 cells/kg.

DISCUSSION

Both the pre-CD34 and the MRp-CD34 were significantly correlated with CD34-FP. However, the CD34-FP was more reliably predicted by MRp-CD34. Early availability of mid-run CD34 values was associated with a significant reduction in the number of LP required to collect 5x10(6) CD34 cells/kg, without reduction in the number of CD34 cells for transplant or prolongation of days to neutrophil or platelet engraftment.

Rapid mobilization of CD34+ cells following administration of the CXCR4 antagonist AMD3100 to patients with multiple myeloma and non-Hodgkin's lymphoma

PURPOSE

Interactions between the chemokine receptor CXCR4 and its ligand stromal derived factor-1 regulate hematopoietic stem-cell trafficking. AMD3100 is a CXCR4 antagonist that induces rapid mobilization of CD34+ cells in healthy volunteers. We performed a phase I study assessing the safety and clinical effects of AMD3100 in patients with multiple myeloma (MM) and non-Hodgkin's lymphoma (NHL).

PATIENTS AND METHODS

Thirteen patients (MM, n=7; NHL, n=6) received AMD3100 at a dose of either 160 microg/kg (n=6) or 240 microg/kg (n=7). WBC and peripheral blood (PB) CD34+ cell counts were analyzed at 4 and 6 hours following injection.

RESULTS

AMD3100 caused a rapid and statistically significant increase in the total WBC and PB CD34+ counts at both 4 and 6 hours following a single injection. The absolute CD34+ cell count increased from a baseline of 2.6 +/- 0.7/microL (mean +/- SE) to 15.6 +/- 3.9/microL and 16.2 +/- 4.3/microL at 4 hours (P=.002) and 6 hours after injection (P =.003), respectively. The absolute CD34+ cell counts observed at 4 and 6 hours following AMD3100 were higher in the 240 microg/kg group (19.3 +/- 6.9/microL and 20.4 +/- 7.6/microL, respectively) compared with the 160 microg/kg group (11.3 +/- 2.7/microL and 11.3 +/- 2.5/microL, respectively). The drug was well tolerated and only grade 1 toxicities were encountered.

CONCLUSION

AMD3100 appears to be a safe and effective agent for the rapid mobilization of CD34+ cells in patients who have received prior chemotherapy. Further studies in combination with granulocyte colony-stimulating factor in patients with lymphoid malignancies are warranted.

Analysis of remobilization success in patients undergoing autologous stem cell transplants who fail an initial mobilization: risk factors, cytokine use and cost

Inadequate stem cell mobilization is seen in approximately 25% of patients undergoing autotransplantation for hematologic malignancies. Remobilization strategies include chemotherapy/cytokine combinations or high-dose cytokines alone or in combination. From 1/1997 to 7/2002, we remobilized 86 patients who failed an initial mobilization (median total CD34=0.72 x 10(6)/kg) in sequential cohorts using high-dose G-CSF (32 microg/kg/day) or G-CSF(10 microg/kg/day)+GM-CSF (5 microg/kg/day). No difference in CD34/kg yields were seen (G-CSF alone: 2.2 x 10(6) and G-CSF+GM-CSF 1.6 x 10(6)) in the median 3 aphereses performed (P=0.333). Of the 86, 23 (27%) failed the second mobilization; 14 were remobilized again (yield=1.5 x 10(6) CD34/kg; three aphereses). Of the 86, 93% went to transplant: three progressed, and three had inadequate stem cells. Significant risk factors for a failed remobilization were: number of stem-cell-damaging regimens (P=0.015), time between last chemotherapy and first mobilization (P=0.028), and higher WBC at initiation of first mobilization (P=0.04). High-dose G-CSF (32 microg/kg/day) was more costly @ USD $9,016, vs $5,907 for the G-CSF+GM-CSF combination (P<0.001). Most patients failing an initial mobilization benefit from a cytokine only remobilization. Lower cost G-CSF+GM-CSF is as effective as high-dose G-CSF.

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.

An evaluation of predictive factors for CD34+ cell harvest yields from patients mobilized with chemotherapy and growth factors

BACKGROUND

Accurately predicting the outcomes of peripheral blood stem cell harvests is important because unproductive collections are expensive and subject the donor to unnecessary toxicity.

STUDY DESIGN AND METHODS

Predictive factors for stem cell mobilization and collection by a retrospective review of 104 consecutive donors were evaluated.

RESULTS

Of several previously suggested measures, the peripheral CD34+ cell concentration on the day of harvest (pCD34DH) correlated best with total numbers of CD34+ collected (r = 0.88). This was followed by the pCD34 on the day before harvest (pCD34Day -1) (r = 0.74). The peripheral WBC count on the day of harvest (pWBC) was inferior (r = 0.39). When ratios of potential predictive factors divided by the previous day's value were examined, pWBC ratio was found to be a significant independent predictive factor for cells collected (r = 0.45). Furthermore, the predictive value of both the pCD34Day -1 and the pWBC can be improved by combining with the pWBC ratio. To examine whether the chosen collection starting days were optimal, serial pCD34 obtained daily during the harvest procedures was examined. Poorly mobilizing donors, who required several days of collection, did not reach maximal harvest yields until the fourth collection day.

CONCLUSIONS

pCD34DH is the optimal predictive factor for harvest yields. If pCD34DH is not available, pCD34Day -1 or pWBC combined with the pWBC ratio may offer the best prediction of harvest outcomes. The best harvest yields on poorly mobilizing donors occur 3 to 4 days after the usual collection starting times.

Stem cell mobilization

Successful blood and marrow transplant (BMT), both autologous and allogeneic, requires the infusion of a sufficient number of hematopoietic progenitor/stem cells (HPCs) capable of homing to the marrow cavity and regenerating a full array of hematopoietic cell lineages in a timely fashion. At present, the most commonly used surrogate marker for HPCs is the cell surface marker CD34, identified in the clinical laboratory by flow cytometry. Clinical studies have shown that infusion of at least 2 x 10(6) CD34(+) cells/kg recipient body weight results in reliable engraftment as measured by recovery of adequate neutrophil and platelet counts approximately 14 days after transplant. Recruitment of HPCs from the marrow into the blood is termed mobilization, or, more commonly, stem cell mobilization. In Section I, Dr. Tsvee Lapidot and colleagues review the wide range of factors influencing stem cell mobilization. Our current understanding focuses on chemokines, proteolytic enzymes, adhesion molecules, cytokines and stromal cell-stem cell interactions. On the basis of this understanding, new approaches to mobilization have been designed and are now starting to undergo clinical testing. In Section II, Dr. Michele Cottler-Fox describes factors predicting the ability to mobilize the older patient with myeloma. In addition, clinical approaches to improving collection by individualizing the timing of apheresis and adjusting the volume of blood processed to achieve a desired product are discussed. Key to this process is the daily enumeration of blood CD34(+) cells. Newer methods of enumerating and mobilizing autologous blood HPCs are discussed. In Section III, Dr. John DiPersio and colleagues provide data on clinical results of mobilizing allogeneic donors with G-CSF, GM-CSF and the combination of both as relates to the number and type of cells collected by apheresis. Newer methods of stem cell mobilization as well as the relationship of graft composition on immune reconstitution and GVHD are discussed.

Predictive value of circulating immature cell counts in peripheral blood for timing of peripheral blood progenitor cell collection after G-CSF plus chemotherapy-induced mobilization

BACKGROUND

Enumeration of CD34+ cells in peripheral blood (PB) before apheresis predicts the number of CD34+ cells collected, although flow cytometric techniques used are complex and expensive. In an attempt to determine the optimal timing for peripheral blood progenitor cell (PBPC) collection, the usefulness of circulating immature cell (CIC) counts in PB was evaluated.

STUDY DESIGN AND METHODS

CIC counts in PB and CD34+ cell counts in the apheresis product from 249 collections were assessed, and the relationship between these two parameters was evaluated by with the Pearson rank correlation analysis, the Fisher exact test, and the U-test.

RESULTS

CIC counts were correlated significantly with the number of CD34+ cells per kg of patient's body weight in the apheresis product (Pearson rank correlation analysis: r = 0.635, p < 0.0001). When a level of 1 x 10(9) CICs per L was selected as a cutoff value, the sensitivity and specificity for collecting more than 1 x 10(6) CD34+ cells per kg of body weight were 75.7 and 85.5 percent, respectively.

CONCLUSION

The present study strongly suggests that the number of CICs in PB may estimate the number of CD34+ cells collected. The data indicate that CIC counts above 1 x 10(9) per L can be used as a good predictor for PBPC collections containing more than 1 x 10(6) CD34+ cells per kg of body weight in a single apheresis procedure.

Monitoring of peripheral blood CD34+ cell counts on the first day of apheresis is highly predictive for efficient CD34+ cell yield

The purpose of this study was to evaluate the correlation of preleukapheresis circulating CD 34+ cells/micro L, white blood cells (WBC), and platelet counts on the first day of apheresis with the yield of collected CD 34+ cell counts in 40 patients with hematological malignancies (n = 29) and solid tumors (n = 11). The median numbers of apheresis cycles, numbers of CD 34+ cells, peripheral blood (PB) mononuclear cells, and total nucleated cells collected were 2 (range, 1-4), 5.5 x 106/kg (range, 0.05-33.78), 2.59 x 108/kg (range, 0.04-20.68), and 7.36 x 108/kg (range, 0.15-28.08), respectively. There was a strong correlation between the number of preleukapheresis circulating CD 34+ cells/micro L and the yield of collected CD 34+ cells per kilogram (r = 0.962, p < 0.001). The threshold levels of PB C 34+ cell/micro L to obtain > or =1 x 106/kg and > or =2.5 x 106/kg CD 34+ cell in one collection were 12/micro L and 34/ micro L, respectively. Fifteen of 17 (88%) patients who had > or =34 CD 34+ cells/ micro L in the PB before collection reached the level of > or =2.5 x 106/kg in a single apheresis. Despite a low r value, WBC and platelet counts on the first day of apheresis also correlated with the yield of collected daily CD 34+ cells per kilogram (r = 0.482, p < 0.01 and r = 0.496 p < 0.01, respectively). These data suggest that preleukapheresis circulating CD 34+ cells/ micro L correlated significantly better with the yield of collected CD 34+ cells than WBC and platelet counts on the first day of apheresis. Using a value of 34/micro L preleukapheresis circulating CD 34+ cells as a guide for the timing of peripheral blood stem cells collections can be time saving and cost-effective.

Breast tumor contamination of PBSC harvests: tumor depletion by positive selection of CD34(+) cells

BACKGROUND

Positive selection of CD34(+) cells may reduce or eliminate tumor cells contaminating PBSC harvests of breast cancer (BrCa) patients. However, to assess tumor purging accurately methods may be needed that are of higher sensitivity than standard immunocytochemistry (ICC) assays.

METHODS

BrCa-cell depletion, resulting from CD34(+) cell selection, was evaluated using a novel, highly sensitive assay based upon immunomagnetic enrichment with ICC detection in 36 BrCa patients undergoing highdose chemotherapy with autologous PBSC support.

RESULTS

The prevalence of BrCa-cell contamination was significantly lower (P = 0.0078) in selected CD34(+) cell fractions (17/35, 49%) from apheresis collections compared with CD34(-) cell fractions (25/35, 71%). In 8/34 (24%) patients, BrCa cells were detected in CD34(-) cell fractions, but not in paired CD34(+) cell fractions. Significantly lower total numbers (P < 0.0005) of BrCa cells were enumerable in CD34(+) cell fractions compared with corresponding apheresis harvests. The median total BrCa-cell content of selected CD34(+) cell fractions with measurable contamination was 22 BrCa cells (range, 6-73 BrCa cells), compared with 3297 BrCa cells (range, 10-98 400 BrCa cells) in apheresis harvests. The median log depletion of BrCa cells achieved by positive CD34(+) cell selection in specimens with detectable contamination both before and after selection was 2.2 (range, 1.7-4.0). Total pre-selection BrCa cell number was significantly predictive (P = 0.004) of residual detectable post-selection contamination.

DISCUSSION

Positive CD34(+) cell selection is an effective tumor purging strategy. The prevalence of PBSC contamination in BrCa patients is substantially higher than formerly appreciated.

Mobilization of allogeneic peripheral blood progenitor cells

It is possible to reliably obtain sufficient PBSC from most normal donors to perform allogeneic transplantation. The mobilization regimen, usually administration of a single daily dose of G-CSF at 7.5 to 10 micrograms/kg subcutaneously for 4 to 6 days, is tolerable with acceptable side effects. However, there is wide variability among individuals with respect to the extent of mobilization achieved by the regimen and the optimal timing of apheresis. Studies suggest that the likelihood of obtaining an adequate harvest of CD34+ cells, as defined locally may be enhanced by employing higher doses or different schedules of G-CSF, monitoring the mobilization and/or collection of PBPC, and using apheresis procedures processing 2 or more times blood volume. However, an optimal regimen for mobilization and harvesting for all donors has not yet been identified and a small percentage of donors may not mobilize adequately with G-CSF. Alternative regimens employing combinations of G-CSF and GM-CSF are available that may prove useful in such cases and novel cytokines that are even more effective than G-CSF in mobilizing stem cells are eagerly awaited. Based on currently available experience with normal donors, the short-term safety of G-CSF appears to be acceptable, however there exist several scenarios in which marrow harvesting may be preferable to G-CSF mobilization and apheresis collection of PBPC.

Trafficking of CD34+ cells into the peripheral circulation during collection of peripheral blood stem cells by apheresis

The number of CD34+ cells collected during apheresis is related to the volume of blood processed. In large-volume apheresis (LVL) procedure, more cells can be collected than were originally present in the peripheral blood at the start of the collection procedure. We prospectively studied the levels of CD34+ cells in the blood and apheresis product during LVL procedures for 21 patients with acute myelogenous leukemia or multiple myeloma. These patients experienced a slow decline in blood CD34+ cell concentrations during the apheresis procedure. No patient demonstrated a sustained rise in CD34+ cell counts as a result of the procedure. The number of CD34+ cells collected exceeded the number calculated to be in the peripheral blood at the start of the procedure by an average of 3.0-fold. The efficiency of collection for CD34+ cells averaged 92.6% and did not vary with speed of blood processing, diagnosis, or mobilization regimen. The calculated release of CD34+ cells from other reservoirs into the peripheral blood averaged 3.71 x 10(6)/min (range, 0.36-13.7 x 10(6)/min), and correlated (r = 0.82) with the concentration of these cells in the peripheral blood at the start of the procedure. These data show that the apheresis procedure used in this study does not affect the release of CD34+ cells in a cytokine-treated patient. LVL will result in collection of larger quantities of CD34+ cells than procedures involving processing of smaller volumes of blood, but the number of cells collected is limited by the rate of release of these cells into the peripheral circulation where they are accessible for collection.

Kinetics of standardized large volume leukapheresis (LVL) in patients do not show a recruitment phenomenon of peripheral blood progenitor cells (PBPC)

Although several studies have demonstrated the efficacy of large volume leukapheresis (LVL) to yield high numbers of peripheral blood progenitor cells (PBPC), the mechanisms of stem cell release into circulation and the postulated phenomenon of PBPC recruitment during apheresis have not been investigated in detail. Therefore, we analyzed the kinetics of stem cell enrichment in a total of 34 standardized LVL for patients with hematologic malignancies (lymphoma, multiple myeloma) and solid tumors (breast cancer, rhabdomyosarcoma). LVL was started 2 h after administration of G-CSF processing six times the patient's blood volume. Cells were sequentially collected into six bags and the numbers of leukocytes, mononuclear cells (MNC), CD34+ cells and colony-forming cells (CFU-GM) in each collection bag were analyzed. The numbers of PBPC collected demonstrated a continuous decrease starting after an early maximum during the second processed blood volume (P = 0.001). Interestingly, these kinetics of decreasing stem cell yields during LVL were similar for both entities of patients with hematologic malignancies as well as for both groups of patients with solid tumors. In summary, a recruitment phenomenon, defined as a time-dependent and LVL-induced increase of PBPC, could not be demonstrated in any of the diseases investigated.

Bone Marrow Transplantation: Prognostic Factors of Peripheral Blood Stem Cell Mobilization with Cyclophosphamide and Filgrastim (r-metHuG-CSF): The CD34+ Cell Dose Positively Affects the Time to Hematopoietic Recovery and Supportive Requirements after High-Dose Chemotherapy

To prospectively analyze factors that influence peripheral blood stem cell (PBSC) collection and hematopoietic recovery after high-dose chemotherapy (HDC), 39 patients received cyclophosphamide 4 g/m(2) and rHuG-CSF (Filgrastim) 5 &mgr;g/kg/day. Leukapheresis was started when CD34(+) cells/mL were > 5 x 10(3). A minimum of 2 x 10(6) CD34(+) cells/kg was collected. Median steady-state bone marrow CD34(+) cell percentage was 0.8% (range, 0.1 to 6). Thirty-two patients received HDC with autologous PBSC transplantation plus Filgrastim. A median of 2 (range, 0 to 6) leukapheresis per patient were performed and a median of 6.3 x 10(6) CD34(+) cells/kg (range, 0 to 44.4) collected; four patients failed to mobilize CD34(+) cells. The number of cycles of prior chemotherapy had an inverse correlation with the number CD34(+) cells/kg collected (r = -0.38; p < 0.005). Patients with <7 cycles had a higher predictability for onset of leukapheresis than patients with (3) 7 (93% versus 50%; p < 0.005). The four patients who failed to mobilize had received >/=7 cycles. The number of CD34(+) cells/kg infused after HDC had an inverse correlation with days to recovery to 0.5 x 10(9) neutrophils/L and 20 x 10(9) platelets/L (r = -0.68 and -0.56; p < 0.005). The effect of these factors on mobilization and hematopoietic recovery were confirmed by multivariate analysis. Requirements for supportive measures were significantly lower in patients given a higher dose of CD34(+) cells/kg. Therefore, PBSC collection should be planned early in the course of chemotherapy. Larger number of CD34(+) cells/kg determined a more rapid hematopoietic recovery and a decrease of required supportive measures.

Correlation of hematopoietic progenitor cell count determined by the SE-automated hematology analyzer with CD34(+) cell count by flow cytometry in leukapheresis products

The yield of stem cell collection after mobilization is crucial for autologous peripheral blood stem cell (PBSC) transplantation. Quantitative determinations of CD34(+) cells using flow cytometry or stem cell culture have been used, but these methods require much time, technical experience, and expensive reagents. The automated hematology analyzer (Sysmex SE-9000trade mark, TOA, Japan) equipped with the Immature Information (IMI) channel for immature myeloid cells can detect IMI(+) cells within 90 sec. Detection is made possible by the combination of a special reagent system and direct current/radiofrequency biosensors. We studied the relation of IMI(+) cells and variable cell counts with CD34(+) cell yield in autologous stem cell harvest. In a series of 32 patients (median age, 44 years; M:F = 11:21), 184 leukaphereses were performed after mobilization regimens with chemotherapy and G-CSF or G-CSF alone. Full blood cell counts were enumerated on peripheral blood (PB) samples taken prior to each leukapheresis. Mononuclear cell (MNC) and IMI(+) cell counts by automated hematology analyzer and flow cytometry based CD34(+) cell yield were measured on the harvested product. The relationship among PB white blood cells (WBC), PB monocytes, IMI(+) cells, MNC, and CD34(+) cell yield in a single leukapheresis was estimated by Pearson correlation analysis. PB WBC count showed no correlation with CD34(+) cell yield in a single leukapheresis (r = 0.02, P = 0.81). PB monocyte count showed a weak correlation (r = 0.21, P = 0.01) and MNC in harvest also showed a weak correlation (r = 0.36, P = 0.0001) with CD34(+) cell yield. In contrast, CD34(+) cell yield correlated well with IMI(+) cell count (r = 0.68, P = 0.0001), and data could be fitted by a linear regression equation, y = 0.330 + 0.974x. IMI(+) cell assay by the automated hematology analyzer correlated well with the CD34(+) cell yield in a mobilized autologous stem cell harvest. The IMI(+) cell count might be used as a simple and efficient indicator of blood stem cell mobilization and collection.

Non-cryopreserved peripheral blood progenitor cells collected by a single very large-volume leukapheresis: a simplified and effective procedure for support of high-dose chemotherapy

High-dose chemotherapy with autologous peripheral blood progenitor cell (PBPC) support has become a widely used treatment strategy. In order to simplify the procedure, a single very large-volume leukapheresis programme combined with short-term refrigerated storage of the PBPC was developed. Seventy-two patients suffering from various relatively chemosensitive malignancies received high-dose chemotherapy, consisting of agents with short in vivo half-lives and 24 to 48 hours later, the refrigerated PBPC were reinfused. A single very large-volume apheresis was sufficient to obtain at least 2 x 10(6)/kg CD34+ cells in 58 patients (81%), and 63% had at least 2.5 x 10(6) CD34+ cells/kg. Only two patients (3%) were transplanted with less than 1 x 10(6) CD34+ cells/kg. In three patients (4%) leukapheresis was repeated because of insufficient number of PBPC. The median CD34+ cell count was 3 x 10(6)/kg. A median of 38.5 L blood (range, 21 to 59) was processed, which accounted for a median of 9 x patient's total blood volume. Very large-volume leukapharesis was well tolerated with symptomatic hypocalcemia being the most common (18%) side-effect. The median time to neutrophils >1.5 x 10(9)/L, and to self-supporting platelet count >25 x 10(9)/L, was 10 and 12 days after reinfusion of PBPC graft, respectively. There were no treatment-related deaths. Our results indicate that this simplified approach of PBPC transplantation can be associated with prompt hematologic recovery in most patients and that it can be useful in settings where facilities are limited or for certain diseases where conditioning regimens with short half-life are appropriate. J. Clin. Apheresis, 15:236-241, 2000.

Cytokines and vascular cell adhesion molecule-1 in the blood of patients undergoing HPC mobilization

BACKGROUND

The mechanism of HPC mobilization in humans is unclear. In this study, the relationship between PBPC mobilization and blood levels of G-CSF, endogenous cytokines (IL-8, SCF, thrombopoietin [TPO]), and the vascular cell adhesion molecule-1 (VCAM-1) was analyzed in patients with malignancy who were undergoing a PBPC mobilization regimen.

STUDY DESIGN AND METHODS

Fifty-four patients with multiple myeloma (MM) and 29 with breast cancer (BC) underwent a mobilization regimen combining conventional chemotherapy and G-CSF up to the last day of PBPC collection. The CD34+ cell count was determined on each day when leukapheresis was scheduled. Venous blood samples (n = 117) were drawn before apheresis for CD34+ cell count (flow cytometry) and cytokine (G-CSF, IL-8, SCF, TPO) and VCAM-1 measurements (ELISA).

RESULTS

In multiple regression analysis, SCF was a significant determinant of CD34+ cell levels in BC patients (R = 0.50, p = 0.03) and of VCAM-1 levels in MM patients (R = 0.32, p = 0.02). SCF was negatively correlated with CD34+ cell count in patients with BC. SCF and VCAM-1 blood levels were correlated in MM and BC patients.

CONCLUSION

SCF and VCAM-1 could play a role in PBPC mobilization in patients and could be useful measures by which to study patients undergoing a mobilization regimen.

Induction of the chemokine stromal-derived factor-1 following DNA damage improves human stem cell function

The chemokine stromal-derived factor-1 (SDF-1) controls many aspects of stem cell function. Details of its regulation and sites of production are currently unknown. We report that in the bone marrow, SDF-1 is produced mainly by immature osteoblasts and endothelial cells. Conditioning with DNA-damaging agents (ionizing irradiation, cyclophosphamide, and 5-fluorouracil) caused an increase in SDF-1 expression and in CXCR4-dependent homing and repopulation by human stem cells transplanted into NOD/SCID mice. Our findings suggest that immature osteoblasts and endothelial cells control stem cell homing, retention, and repopulation by secreting SDF-1, which also participates in host defense responses to DNA damage.

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.

Use of PEG-rHuMGDF in platelet engraftment after autologous stem cell transplantation

This paper summarizes a pilot, sequential dose-escalation study of PEG-rHuMGDF in patients with advanced malignancies who had delayed platelet recovery after autologous stem cell transplantation (ASCT). Patients were randomized to receive either placebo (n = 11) or PEG-rHuMGDF at 5 (n = 9), 10 (n = 6), or 25 (n = 7) microg/kg/day by subcutaneous injection for 14 days and were monitored for 5 weeks. Across all treatment groups, eight patients had platelet recovery to > or = 20 x 10(9)/l by day 21. The proportion of patients achieving platelet recovery, the median number of days and units of platelet transfusions were similar for the placebo and the PEG-rHuMGDF groups. PEG-rHuMGDF was well tolerated at all dosages. The incidence rates of adverse events in all groups were similar. No deaths on study, no drug-related serious adverse events, and no development of neutralizing antibodies to MGDF occurred.

Stem Cell Collection using the Dideco Excel Continuous Flow Blood Cell Separator: Parameters for Optimal Stem Cell Collection Timing

This study evaluates stem cell collection procedures performed with the Dideco Excel blood cell separator, with particular attention given to yields and separator collection efficiencies. Patients’ blood precounts and yield parameters related to the harvest capacity of the collection system were investigated. Fifty-five collection procedures were analyzed in 32 patients suffering from hematological malignancies and solid tumors and mobilized with chemotherapy plus G-CSF. The median blood volume processed in each procedure was 15.8 liters (12–19.750), with a blood flow rate of 70 ml/min. Patients had the following median blood precount value: NC 7.81×109/L, CD34+ cells 49.08×103/ml. Leukapheresis procedures gave the following yields: NC 14.95×109, MNC 10.83×109, CD34+ cells 4.37×106; yields/kg, NC 0.21×109kg, MNC 0.15×109/kg CD34+ cells 4.26×106/kg. Procedures show the following collection efficiencies: NC 10.79%, MNC 29.06%, CD34+ 42.33%, PLT 26.5%. The RBC (red blood cell) contamination of the product was (median value) 20.9 ml for each procedure, and for platelets 1.76×1011 per procedure. The CD34+ cell precounts strongly correlated with the CD34+ yields/kg (r=0.82. p=0.000). Furthermore the NC and MNC precounts correlated with the CD34+ yields/kg but only the MNC precount correlation is notable (r=0.57, p=0.000). The logistic regression analysis shows that CD34+ (p=0.008) but not NC (po=0.14), MNC (p=0.09), or PLT (p=0.53) precounts significantly influenced the collection of a sufficient dose of CD34+ cells for transplantation (≥ 2.5×106/kg). Eleven of the thirty-two patients have been transplanted till now, and all had a prompt and lasting trilineage engraftment NC >1×109/L on day 12 (10–17). Our data show that the collection system analyzed in this report is able to collect large amounts of progenitor cells, harvesting ≥2.5×106/kg CD34+ cells with a single procedure in 68.8% of patients and assuring complete recovery after stem cell transplantation.

Morphologic, immunophenotypic and in vitro growth characteristics of blood and bone marrow associated with stem cell mobilisation in patients with lymphoma

The proportion of CD34+ cells in the bone marrow (BM) is predictive of the size of progenitor cell mobilisation into the blood (PB). To investigate which other PB and BM parameters may be related to mobilisation, we analysed at steady state PB and BM of 23 patients with relapsed or resistant lymphoma before administering high-dose cyclophosphamide and G-CSF Cell morphology, number of CD34+ cells, and growth in clonogenic assay and in long-term cultures (LTC) were determined and then correlated with mobilisation extent (CD34+ and GM-CFC) and quality (growth of harvested cells in LTC). We found that the good mobilising patients (CD34 > 50 x 10(3)/ml, n=10) had several baseline BM characteristics (number of CD34+ MNC, GM-CFC, BFU-E, production of CFCs in LTC) similar to a group of 12 healthy controls, while patients with reduced mobilisation (CD34 < 50 x 10(3)/ml, n=13) had clearly reduced BM progenitors and LTC growth (p< 0.05). In a multivariate analysis including baseline clinical, blood and bone marrow characteristics, the most significant PB and BM factors independently associated with a higher number and/or quality of mobilised cells were a higher number of CD34+ and GM-CFC in the BM and a higher baseline haemoglobin, platelet, and CD34+ blood count. The capacity to release progenitor cells into the circulation is therefore not predicted by the distribution of morphologically distinguishable cells, marginally predicted by the BM content of highly undifferentiated cells (growth in long term culture), while it is proportional to the number of BM progenitors (CD34+, GM-CFC and BFU-E).

Mobilization of peripheral-blood stem cells by concurrent administration of daniplestim and granulocyte colony-stimulating factor in patients with breast cancer or lymphoma

PURPOSE

To evaluate the safety and hematopoietic activity of daniplestim administered concurrently with granulocyte colony-stimulating factor (G-CSF) for peripheral-blood stem-cell (PBSC) mobilization.

PATIENTS AND METHODS

In the initial dose-escalation phase, 25 patients with adenocarcinoma of the breast (AB; 13 patients) or lymphoma (12 patients) were given daniplestim at doses ranging from 0.1 to 3.75 microgram/kg/d plus G-CSF 10 microgram/kg/d. In the randomized phase, 52 patients with AB (27 patients) or lymphoma (25 patients) were randomized within disease categories to the daniplestim dose chosen in the dose-escalation phase plus G-CSF 10 microgram/kg/d (D+G) or placebo plus G-CSF 10 microgram/kg/d (P+G) for up to 7 days.

RESULTS

A daniplestim dose of 2. 5 microg/kg/d was chosen for further study because it was hematopoietically active and had an acceptable side-effect profile. In the randomized phase, in patients with AB, D+G was associated with a higher probability (P =.0696) of collecting >/= 2.5 x 10(6) CD34(+) cells/kg and significantly higher circulating CD34(+) cell counts (P =.0498) on days 6 through 9 after the initiation of dosing. The target level was more likely to be reached with additional leukaphereses in the patients given D+G. Patients given P+G did not benefit from additional leukaphereses beyond the first procedure. The type of mobilization did show a trend toward a shorter duration of neutropenia in the D+G group. The adverse events with D+G consisted largely of mild to moderate flu-like symptoms, including headache and fever, and occurred more frequently than with P+G.

CONCLUSION

Daniplestim administered at 2.5 microgram/kg/d is tolerable and active when combined with G-CSF, and the combination may prove more effective than G-CSF alone in promoting the collection of adequate numbers of CD34(+) cells for PBSC infusion in patients with AB.

Kinetic study of CD34+ cells during peripheral blood stem cell collections

The impact of the separated volume on the yield of CD34+ cells during peripheral blood stem cell collections (PBSCC) remains controversial. We therefore studied the CD34+ cell concentration in the peripheral blood of patients (pts) during PBSCC as well as the total amount of CD34+ cells collected after each blood volume (BV) processed and engraftment data for each cycle of high dose chemotherapy (HD Ctx). A total of 21 PBSCC from 20 patients with different malignancies were analyzed. Stem cells were mobilized by chemotherapy and G-CSF (14 pts) or GM-CSF (6 pts). Samples from the pts peripheral blood and the collection bag were taken after each BV processed and analyzed for CD34+ cells, WBC, platelets (plt), and hemoglobin (Hb). The total volume processed was two to five times the pts calculated BV (mean value 17.4 L, range 9.0-24.0 L). Sixteen pts could be evaluated for engraftment. The mean peripheral blood CD34+ cell count was 116+/-103.5/microl at the start of PBSCC and decreased to 57+/-61.6/microl after processing of four times the pts BV. The mean number of CD34+ cells collected after each BV was 2.3+/-2.4, 5.8+/-5.2, 8.5+/-7.2, and 11.8+/-10.3x10(6) per kg body weight, respectively. The mean plt count decreased by 53+/-40.2/nl, Hb by 1.+/-0.5 g/dl and WBC by 0.+/-6.1/nl after separation of 4 BV. All but two pts reached the target value of 1.5x10(6) CD34+ cells/kg body weight and planned cycle of HD Ctx with 1 PBSCC. All pts engrafted and reached neutrophils>500/microl and plt>20,000/microl at a median of 11 and 13 days, respectively. We could demonstrate, that the yield of CD34+ cells during PBSCC increased continuously with the volume of the separated BV and that up to 5x the patients' BV could be processed safely without serious side effects. Most pts had to undergo only 1 PBSCC to collect sufficient numbers of CD34+ cells to support sequential courses of HD Ctx without delayed engraftment.

Enumeration of HPC in mobilized peripheral blood with the Sysmex SE9500 predicts final CD34+ cell yield in the apheresis collection

Enumeration of CD34+ cells in the peripheral blood before apheresis predicts the quantity of those cells collected, although the cytometric techniques used are complex and expensive. We found that a subpopulation of lysis-resistant cells in the peripheral blood, identified by the Sysmex SE9500 and designated as HPC, can serve as a surrogate marker predictive of the yield of CD34+ cells. Spearman's rank statistics were used to examine the correlation between WBC, MNC, HPC and CD34+ cells in the peripheral blood and final CD34+ cell yield for 112 samples of peripheral blood and matching apheresis collections from 66 patients and donors. The results indicate that WBC and MNC in the peripheral blood were poor predictors of CD34 content, while HPC gave a correlation coefficient of 0.62. The positive predictive values of different cutoff levels of HPC in the peripheral blood ranging from 5 to 50 x 106/l increased from 0.80 to 0.93 when the target collection was 1 x 106cells/kg. However, for patients with HPC levels below various cutoff levels, the proportion of the collections not reaching that target goal ranged between 0.36 and 0.43, indicating that most collections will still exceed the target goal of CD34+ cells. When the target collection was 2.5 x 106 CD34+ cells/kg, the positive predictive value was lower and negative predictive value was higher.

Peripheral blood progenitor cell mobilization in healthy donors receiving recombinant human granulocyte colony-stimulating factor

OBJECTIVE

We analyzed the incidence of primitive (LTC-IC) and committed (CFU-mix, BFU-E, CFU-GM) hematopoietic progenitors detected under steady-state conditions and upon progenitor cell mobilization in a cohort of healthy donors receiving recombinant human granulocyte colony-stimulating factor (rhG-CSF).

MATERIALS AND METHODS

Healthy donors (n = 30) of HLA-mismatched or -matched stem cell transplants were mobilized with rhG-CSF (8 microg/Kg body weight subcutaneously twice daily until completion of leukapheresis). PBPC collections were started after 4 days of rhG-CSF therapy.

RESULTS

Steady-state incidence of bone marrow LTC-IC, but not committed progenitors, significantly correlated with the numbers of mobilized CD34+ cells (r = 0.6, p = 0.004), CFU-GM (r = 0.79, p = 0.0005) and CFC (r = 0.76, p = 0.001) detected after 4 days of rhG-CSF therapy. Statistically significant correlations were also found between steady-state blood CFU-GM and peak numbers of CD341 cells (r = 0.68, p = 0.001), numbers of day 4 CD341 cells (r = 0.52, p = 0.005), CFU-GM (r = 0.63, p = 0.002), and CFC (r = 0.61, p = 0.003).

CONCLUSION

Our data show that in normal volunteers baseline marrow LTC-IC and blood CFU-GM correlate with rhG-CSF-mobilized PBPC. The potential clinical relevance of these findings in the identification of poor mobilizers will be tested in a prospective study.

Volume-dependent collection of peripheral blood progenitor cells during large-volume leukapheresis for patients with solid tumours and haematological malignancies

We investigated the efficacy of peripheral blood progenitor cell (PBPC) collection during large-volume leukapheresis (LVL) in patients with solid tumours and haematological malignancies (n = 18). The time- and volume-dependent harvest of leucocytes (WBC), mononuclear cells (MNC), CD34+ cells and colony-forming cells (CFU-GM) during LVL was analysed in six sequentially filled collection bags processing four times the patient's blood volumes. The amounts of leucocytes (WBC) and the purity of mononuclear cells (MNC%) did not show any significant changes during LVL. The percentage of CD34+ cells remained constant for the first three bags but consecutively decreased from initially 1.71% CD34+ cells in the beginning of LVL to finally 1.34% CD34+ cells (P = 0.02). The mean numbers of colony-forming cells (CFU-GM) decreased from 74 microL-1 to 59 microL-1 during LVL (P = 0.16). Furthermore, the comparison of volume-dependent PBPC collection for patients with high, medium and low total yields of CD34+ cells showed similar kinetics on different levels for the three groups. We concluded that - relative to the initial total amount of PBPC harvested - comparable numbers of progenitor cells can be collected during all stages of LVL with a slight decreasing trend processing four times the patient's blood volumes.

A prospective, randomized, sequential, crossover trial of large-volume versus normal-volume leukapheresis procedures: effect on progenitor cells and engraftment

BACKGROUND

The influence of leukapheresis size on the number of harvested peripheral blood progenitor cells is still unclear. A prospective randomized crossover trial was thus performed, to evaluate the effect of large-volume leukapheresis (LVL) versus normal-volume leukapheresis (NVL) on progenitor cells and engraftment in 26 patients with breast cancer and 15 patients with non-Hodgkin's lymphoma who were eligible for peripheral blood progenitor cell transplantation.

STUDY DESIGN AND METHODS

Patients were randomly assigned to undergo either LVL on Day 1 and on Day 2 or vice versa. The number of progenitor cells was evaluated in the harvest and before and after leukapheresis in the peripheral blood.

RESULTS

The number of harvested CD34+ cells (4.8 x 10(6) vs. 3.4 x 10(6)/kg body weight, p < 0.001) and colony-forming units-granulocyte-macrophage (3.1 x 10(5) vs. 2.4 x 10(5)/kg body weight, p = 0.0026) was significantly higher for LVL procedures than for NVL procedures. The median extraction efficacy, defined as the difference between the yield in the harvest and the decrease in the total number of CD34+ cells in peripheral blood during leukapheresis, was significantly (p < 0.0001) higher for LVL than for NVL (2.6 x 10(8) and 8 x 10(7), respectively). In patients with breast cancer, the median amount of CD34+ cells in the harvest and the median extraction efficacy were higher for LVL than for NVL (p < 0.0001). This was not found for patients with non-Hodgkin's lymphoma.

CONCLUSION

LVL results in a higher yield of CD34+ cells and colony-forming units-granulocyte-macrophage than NVL, but only in patients with breast cancer and with high numbers of CD34+ cells in the peripheral blood before leukapheresis.