Autografting with CD34+ peripheral blood stem cells: retained engraftment capability and reduced tumour cell content

Detection of Breast Cancer Cells in the Bone Marrow or Peripheral Blood: Methods and Prognostic Significance

Tumor cells can reach every anatomic district, organ and tissue through the peripheral blood circulation. Tumor cell shedding is considered an early event in the multi-phase process of metastasis, and the possibility of detecting tumor cells in the bloodstream and/or bone marrow before clinical evidence of distant metastases needs to be explored. The use of new sophisticated diagnostic and investigative techniques has boosted the study of tumor cell contamination of bone marrow and peripheral blood. Molecular techniques, such as reverse-transcriptase polymerase chain reaction, may be useful tools to reach this target, but, today, immunocytochemistry is still considered the gold standard to assess new techniques to detect isolated tumor cells in hematopoietic tissue. Little is known about the biology of isolated tumor cells in the peripheral blood or bone marrow. Two crucial points need to be evaluated: the identification of specific markers of breast cancer cells with clonogenic potential and their biologic properties, and the prognostic impact of the detection of isolated tumor cells in the bone marrow or peripheral blood stem cell collections.

Optimization of the immunomagnetic selection in microcythemic donors enrolled for haploidentical transplantation

BACKGROUND

Immunomagnetic cell selection (ICS) cells is increasingly used in allogeneic hematopoietic transplantation in order to reduce the T cells quantity. The aim of this study was to evaluate an protocol based on Ficoll method before ICS.

STUDY DESIGN AND METHODS

The automated procedure was compared with the standard method. In the group 1 the cell processing involves the extraction of the buffy-coat by Ficoll before incubation with antibodies. This procedure was performed with the Sepax S-100 device. The efficacy of this automated procedure was compared with the group 2. In this group, the cell washing and the incubation were performed through the standard method. The CD34+ cells collected by apheresis (HPC-A) were selected with ICS.

RESULTS

The results obtained after Ficoll procedure, showed a total nucleated cells (TNCs) and CD34+ cells recovery of 85.73% (75.90-90.63; SD 4.25) and 79.31% (51.77-112.31; SD 18.40), respectively. The TNC and CD34+ cells recovery after the pre-incubation washing performed through the standard method, was 75.54% (38.36-97.76; SD 22.5) and 61.51% (30.87-81.79; SD 19.3), respectively. The CD34+ cells recovery after ICS was 79% (51.77-100; SD 18.40) and 44% (15.57-88.24; SD 25.91) in the group 1 and the group 2, respectively. This difference was statistically significant (p=0.001).

CONCLUSION

The efficacy of the ICS which resulted to be higher in the group 1 compared to the group 2. Overall, our data suggest that the Ficoll procedure before incubation is suitable for the clinical routine in the ICS for haploidentical transplantation in patients affected by thalassemia.

Positive immunomagnetic CD34(+) cell selection in haplo-identical transplants in beta-thalassemia patients: removal of platelets using an automated system

BACKGROUND AIMS

Immunomagnetic CD34(+) cell selection (ICS) is utilized in autologous and allogeneic transplants. In the first case it is used to reduce the neoplastic contamination of concentrates, while in the second case it is needed to carry out a T-depletion of cell concentrates in order to reduce the incidence of graft-versus-host disease (GvHD) in patients who have undergone haplo-identical transplants.

METHODS

The efficacy of CliniMACS technology, after reduction of platelet contamination, incubation of monoclonal antibodies (MAb) and successive washings of concentrates, performed in 16 ICS using the standard method without reducing platelet content, was compared with the use of the automated system CytoMate, which was carried out in 46 ICS.

RESULTS

In the group of ICS carried out after automatic manipulation, a significant statistical difference in purity was noted (91.39% versus 83.57, P = 0.017) compared with the group of ICS carried out with the standard procedure. The same significant difference was noted in relation to the remaining percentages of CD3(+) and CD19(+) cells (2.31% versus 5.68%, P = 0.012, and 1.58% versus 2.71%, P = 0.014, respectively). Recovery of CD34+ cells overlapped in the two groups (70.49% versus 68.39%, P = 0.774).

CONCLUSIONS

Immunomagnetic selection carried out using the automated procedure was more efficient, producing a purer sample, more efficient T-depletion and optimal reduction of B cells, without influencing cell recovery. Furthermore, conforming to good manufacturing practice (GMP) guidelines, the entire procedure with CytoMate took place in a contamination-controlled environment.

Ewing Sarcoma tumor cells express CD34: implications for autologous stem cell transplantation

The significance of tumor cell contamination in marrow and peripheral blood stem cell (PBSC) collections of patients with solid tumors remains controversial. Various methods have been developed to purge tumor cells from autologous stem cell products, including CD34+ selection. PBSC harvests from patients with Ewing family of tumors (EFT) were analyzed for contaminating tumor cells prior and after CD34+ selection using reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometry (FC) analyzes. The expression of CD34 was studied by RT-PCR and FC in 14 primary tumors and 13 PBSC harvests, respectively. Tumor cells were identified in the harvests by both methods. In two patients, contaminating tumor cells were evident by RT-PCR only after positive selection. FC analysis confirmed a higher level of tumor cells in the CD34+ fraction. In an attempt to explore this finding, expression of CD34 was detected in 93% of primary tumors and 67% of contaminated harvests. As CD34 is expressed on EFT cells, these cells may be enriched following CD34+ selection of harvests, although the total number of tumor cells is reduced. Other methods of purging, rather than CD34+ selection, should be explored in patients with EFT undergoing autologous stem cell transplantation.

Long-Term Follow-Up of Patients with Non-Hodgkin Lymphoma Following Myeloablative Therapy and Autologous Transplantation of CD34+-Selected Peripheral Blood Progenitor Cells

Graft engineering by CD34(+) selection of peripheral blood progenitor cells (PBPC) has been used in non-Hodgkin lymphoma (NHL) with the aim to reduce relapse related to tumor cells within the graft. From September 1995 to January 2000, 39 patients with newly diagnosed (n = 31) or relapsed (n = 8) NHL were treated in our institution with myeloablative therapy followed by CD34(+) selected autologous PBPC transplantation. Thirty-one patients were diagnosed with follicular lymphoma, and eight patients with mantle-cell lymphoma. All patients had advanced disease (26% of patients stage III and 74% stage IV, Ann Arbor classification). Induction therapy resulted in a complete remission in 17 patients and a partial remission in 22 patients. PBPC were mobilized after cytotoxic chemotherapy with granulocyte colony-stimulating factor support. CD34(+) selection was performed using immunomagnetic beads (Baxter Isolex 300SA or 300i Magnetic Cell Separation System). Most patients (85%) received total body irradiation and high-dose cyclophosphamide as myeloablative regimen. Twelve patients also received rituximab 375 mg/m(2) before radiation and before the start of the cyclophosphamide treatment. The mean CD34(+) cell number for transplantation was 6.5 x 10(6) CD34(+) cells/kg of body weight. Platelet recovery (>20,000/microl median on day 13) and leukocyte recovery (>1,000/microl median on day 12) were within expected range. The estimated median follow-up was 47 months. The probabilities of freedom from progression, overall survival, and event-free survival 4 years after transplantation were 96%, 90%, and 87%, respectively, for patients with follicular lymphoma and 42%, 63%, and 33%, respectively, for patients with mantle-cell lymphoma. Risk factors for relapse were age and extranodal manifestation of disease. The rate of lethal infections in the 12-month follow-up period was 8%. We conclude that CD34(+) selection of autologous transplants following myeloablative therapy is feasible and results in long-term remission in the majority of patients, but the procedure is probably related to a higher rate of lethal infections.

Isolation and transplantation of highly purified autologous peripheral CD34+ progenitor cells: purging efficacy, hematopoietic reconstitution in non-Hodgkin's lymphoma (NHL): results of Japanese phase II study

The purging efficacy of positive selection of autologous CD34+ PBSC with a clinical scale method of magnetic-activated cell sorting system (CliniMACS) was investigated in 48 patients with non-Hodgkin's lymphoma (NHL). The median purity and recovery rate of the CD34+ cells post-selection were 93.3% (range 32.6-99.3) and 72.2% (range 20.5-309.8), respectively. The real-time PCR method to detect the patient-specific monoclonal immunoglobulin heavy chain gene rearrangement (minimal residual tumor; MRT) and CD19 and CD20 positivities were used for the detection of contaminating NHL cells before and after CD34+ selection. After selection, the median (range) depletion rate of MRT was 2.53 (1.52-4.78) log, and that of CD19+ cell and CD20+ cell was 2.46 (0.74-3.64) log and 2.32 (0.40-4.01) log, respectively. In 41 patients, high-dose chemotherapy was performed, followed by the transplantation of the isolated CD34+ cells. Rapid neutrophil recovery as well as platelet recovery was seen with a median time to reach 0.5 x 10(9)/l neutrophils of 10 days (range 8-13) and 20 x 10(9)/l platelets of 14 days (range 10-34), respectively. The present study demonstrated that CliniMACS is a highly effective positive selection method and a high purging efficacy could be obtained without compromising the hematopoietic reconstitution capacity of the graft in NHL patients undergoing high-dose chemotherapy.

Isolation and transplantation of highly purified autologous peripheral CD34+ progenitor cells: purging efficacy, hematopoietic reconstitution following high dose chemotherapy in patients with breast cancer: results of a feasibility study in Japan

BACKGROUND

High-dose chemotherapy with autologous stem cell support may have some therapeutic impact on certain groups of the patients with advanced breast cancer(BRCA). Since stem cell contamination by tumor cells might contribute to relapse, development of a tumor cell purging technique would improve the clinical outcome. The present study was undertaken to evaluate the purging efficacy of autologous mobilized CD34+peripheral stem cells in patients with breast cancer (BRCA) in an advanced stage or relapse.

METHODS

CD34+cells were selected from autologous peripheral blood stem cells (PBSC) using a clinical scale of magnetic-activated cell sorting system (CliniMACS), followed by high-dose chemotherapy with transplantation of CD34+ selected cells. Amplification of cytokeratin 19 (CK19) and 20 (CK20) gene in leukapheresis products were measured to evaluate the performance of tumor cell elimination.

RESULTS

Seven patients were entered into this study. After leukopheresis, 1 patient was dropped form this study due to poor mobilization. Among 6 patient, a total of 8 CD34+ selection was performed. The median purity and recovery rate of the CD34+ cells post selection was 85.1% (range 62.5-98.1%) and 74.2% (range 50.2-90.2%), respectively. After isolation of CD34+cells, the elimination rate in the logarithmic transformation of CK19 was 2.77 log, and that of CK20 were 2.43 log and 2.53 log. In 4 patients, high-dose chemotherapy was performed, followed by the transplantation of the isolated CD34+cells. Rapid neutrophil recovery, as well as platelet recovery was seen with a median time to reach 0.5 x 109/l neutrophils of 9 days(range 8-9), and 20 x 109/l platelets of 12 days (range 10-13). There was no treatment related death and no serious adverse events directly associated with the selection procedure or infusion of selected cells.

CONCLUSIONS

The present study demonstrated that the CliniMACS system is a highly effective positive selection method and that a high purging efficacy could be obtained without compromising the hematopoietic reconstitution capacity of the graft in BRCA patients undergoing high-dose chemotherapy.

Impaired stem cell function of CD34+ cells selected by two different immunomagnetic beads systems

We have been investigating the hematopoietic stem cell (HSC) activity of peripheral blood-derived CD34(+) cells selected by two different laboratory immunomagnetic beads systems (MiniMACS and Isolex 50). In this study, the quality of purified CD34(+) cells was directly compared using clonal cell culture, a cobblestone area-forming cell (CAFC) assay, and an in vivo severe combined immunodeficiency (SCID)-repopulating cell (SRC) assay. It was found that CD34(+) cells selected by these two immunomagnetic methods showed a reduced yield of colony-forming cells and CAFCs compared with cells enriched by the StemSep device (a negative selection method). However, these CD34(+) cells still showed significant SRC activity, including multilineage lymphomyeloid reconstitution. The percentage of human CD45(+) cells in murine bone marrow after transplanting 5 x 10(5) CD34(+) cells selected by the Isolex 50 was significantly lower than after transplanting cells selected by the MiniMACS or the StemSep. Our findings clearly demonstrated that CD34(+) cells selected by the MiniMACS system had superior HSC functions, including SRC activity, compared with cells separated by the Isolex 50 system. More detailed functional analysis of immunomagnetically separated CD34(+) cells may provide useful knowledge for basic research on HSCs as well as for clinical HSC transplantation.

Hemopoietic Recovery and Infectious Complications in Breast Cancer and Multiple Myeloma after Autologous CD34+ Cell-Selected Peripheral Blood Progenitor Cell Transplantation

Autografting with CD34+ cell-selected peripheral blood progenitor cells (PBPC) is often associated with a prolonged recovery time and a higher incidence of infections. The aim of our study was to evaluate whether underlying disease influences hemopoietic recovery and the infectious complications occurring after transplantation. We studied 19 breast cancer (BC) patients and 17 multiple myeloma (MM) patients entered in a high-dose chemotherapy (HDC) program of tandem autografting with CD34+ cell-selected PBPC. PBPC were collected after mobilizing chemotherapy plus granulocyte colony-stimulating factor and were processed for selection of CD34+ cells. After selection, a median of 53% CD34+ cells was recovered with a median final purity of 92% with no significant differences between the MM (52% and 92%, respectively) and BC (53% and 89%, respectively) patients. Medians of 4.5 x 10(6)/kg CD34+ cells (BC, 4.4 x 10(6)/kg; MM, 5.4 x 10(6)/kg) and 18 x 10(4)/kg colony-forming units-granulocyte-macrophage (BC, 21 x 10(4)/kg: MM, 16 x 10(4)/kg) were reinfused after each HDC. Twenty-six patients (10 MM and 16 BC) underwent tandem autografting, and 10 patients received only 1 autograft because of inadequate collection (5 patients), clinical condition (3 patients), and refusal (2 patients). In the BC patients, the HDC regimen included a high-dose melphalan course followed by an ICE (ifosfamide, carboplatin, and etoposide) course. In the MM patients, the regimen consisted of a course of high-dose melphalan therapy and a course of ICBV (idarubicin, cyclophosphamide [Cytoxan], BCNU, and etoposide) or total body irradiation, etoposide, and Cytoxan. We found a significantly prolonged time for neutrophil recovery to > 500/microL in the MM patients (13 days versus 10 days; P < .002), whereas the times for platelet recovery to > 20,000/microL in the two groups were not different (13 days versus 12 days; not significant). No late engraftment failures and no toxic deaths were observed. The incidences of extrahematologic toxicity were similar for the two patient groups. All patients received similar anti-infection prophylaxis for 3 months after transplantation. After 12 months of observation, we found a statistically significant higher incidence of bacterial infections in MM patients in both the early (77.8% versus 48.6%; P < .034) and the late (41.1% versus 0%; P < .014) posttransplantation periods, whereas the incidences of fungal infections were similar in the two groups. Viral infections consisted of herpes zoster virus infection in 2 patients of each group, and cytomegalovirus infection was observed in 3 MM patients and no BC patients. Our experience demonstrates a prolonged neutrophil recovery time and higher incidences of bacterial and viral infections in MM patients compared with BC patients. These observations, although limited by the small sample size, suggest that the underlying disease may influence the incidence of infections after CD34- cell-selected transplantation and should be considered in the planning of appropriate antimicrobial prophylaxis in the autologous transplantation setting.

Quantitative assessment of contaminating tumor cells in autologous peripheral blood stem cells of B-cell non-Hodgkin lymphomas using immunoglobulin heavy chain gene allele-specific oligonucleotide real-time quantitative-polymerase chain reaction

A real-time quantitative-polymerase chain reaction (RQ-PCR) targeting the immunoglobulin heavy chain (IgH) gene has been used for the quantification of minimal residual disease (MRD) in B-cell hematological malignancies. In non-Hodgkin lymphoma (NHL), experimental costs are increased, as a large number of primer-probe sets are required because of diversity, due to somatic and ongoing mutations of the IgH gene. We developed an allele-specific oligonucleotide (ASO) combined with a germline consensus probe-based RQ-PCR assay and examined MRD in peripheral blood stem cells (PBSC). The IgH consensus probes were adapted in seven (50%) of 14 amplifiable cases. Patients with heavily contaminating tumor cells in PBSC relapsed after PBSC transplantation. Our strategy will contribute to the development of a cost-efficient, precisely quantitative and systemic detection assay for MRD in NHL.

Molecular biology of hematopoietic stem cells

Human CD34+ hematopoietic stem and progenitor cells are capable of maintaining a life-long supply of the entire spectrum of blood cells dependent on systemic needs. Recent studies suggest that hematopoietic stem cells are, beyond their hematopoietic potential, able to differentiate into nonhematopoietic cell types, which could open novel avenues in the field of cellular therapy. Here, we concentrate on the molecular biology underlying basic features of hematopoietic stem cells. Immunofluorescence analyses, culture assays, and transplantation models permit an extensive immunological as well as functional characterization of human hematopoietic stem and progenitor cells. New methods such as cDNA array technology have demonstrated that distinct gene expression patterns of transcription factors and cell cycle genes molecularly control self-renewal, differentiation, and proliferation. Furthermore, several adhesion molecules have been shown to play an important role in the regulation of hematopoiesis and stem cell trafficking. Progress has also been made in elucidating molecular mechanisms of stem cell aging that limit replicative potential. Finally, more recent data provide the first molecular basis for a better understanding of transdifferentiation and developmental plasticity of hematopoietic stem cells. These findings could be helpful for non-hematopoietic cell therapeutic approaches.

Clinical applications of CD34+ cell-selected peripheral blood stem cells

Peripheral blood stem cells (PBSC) are increasingly used for stem cell transplantation after high dose chemotherapy. CD34+ cell selection has also been done for use in autologous transplantation studies Bone marrow (BM) may contain tumor cells at the time of harvesting, and on re-infusion, these cells could contribute to a subsequent relapse. Similarly, tumor cell contamination of PBSC collections has been found in a number of studies. Therefore, purging contaminating tumor cells may prevent cases of relapse. As most tumor cell types do not express CD34 antigen, one of the most widespread applications of CD34+ cell selection is likely to be in tumor cell purging. Similarly, CD34+ cell selection has aided allogeneic transplantation studies. Acute graft-versus-host disease (aGVHD) is a major cause of morbidity and mortality in cases of allogeneic transplantation. As aGVHD is mediated by donor T cells, removal of T cells from the graft by CD34+ cell selection may ensure prophylaxis against aGVHD. Further, high-dose immunosuppression followed by CD34+ cell-selected stem cell rescue is theoretically reasonable as a therapeutic tool for patients with autoimmune disease resistant to conventional therapy. However, patients given T cell-depleted transplantation have an increased risk of opportunistic infection as well as malignancies related to immunosuppression; therefore, close monitoring is warranted. We describe here clinical applications of CD34+ cell-selected PBSC for a variety of diseases, with special emphasis on the efficacy as well as drawbacks of this novel technique.

CD34(+) cell enrichment depletes atypical CD30(+) cells from PBPC grafts in patients with HD

BACKGROUND

European Group for Blood and Marrow Transplantation (EBMT) registry data indicate that patients with relapsed HD given high-dose therapy (HDT), supported with PBPC might have a poorer outcome compared with those given BM. Since this can be due to the infusion of contaminating tumor cells in the PBPC products, we studied the presence of minimal residual disease and tested whether CD34(+) cell enrichment was able to remove atypical CD30(+) cells from PBPC grafts.

METHODS

Eighteen HD patients eligible for HDT were included in the study. By the use of immunocytochemistry (ICC), mononuclear cells from BM and peripheral blood (PB) before mobilization, PBPC products and selected CD34(+) fractions were stained using anti-CD30 MAb (Ber-H2) and the APAAP (alkaline phosphatase-anti-alkaline phosphatase) method. Cells scored as atypical CD30(+) cells were large- to medium-sized, with membranous, cytoplasmatic and/or Golgi positivity for CD30.

RESULTS

Nine out of 11 BM tested were positive, while 14 of 14 PB and 18 of 18 PBPC contained atypical CD30(+) cells. The total number of atypical CD30(+) cells was significantly higher in PBPC than in the corresponding BM. CD34(+) cell enrichment employing ISOLEX 300I gave a purity and yield of 99.2% (range 97.8-99.7) and 49.6% (range 30.0-78.4), respectively. After HDT a median of 5.8 x 10(6) (range 2.7-20) CD34(+) cells/kg was infused. Neutrophil counts of > 0.5 x 10(9)/L and platelet counts of > 20 x 10(9)/L were achieved at Day 12 (range 10-17) and at Day 10 (range 7-15), respectively. Sixteen of 18 CD34(+) selected products had no detectable atypical CD30(+) cells, while two had a low number. After HDT, the overall survival was 80% and the event-free survival was 69%, with a median follow-up of 24 months (range 1-36).

DISCUSSION

We show that contaminating atypical CD30(+) cells in PBPC can efficiently be removed by CD34(+) cell enrichment, and the use of such grafts following HDT gives fast and sustained engraftment.

Combined isolation of CD34+ progenitor cells and reduction of B cells from peripheral blood by use of immunomagnetic methods

BACKGROUND

Malignant cells may contribute to relapse after autologous hematopoietic cell transplantation The effectiveness of a double immunomagnetic purging strategy combining CD34-positive with B-negative cell selection to purge peripheral blood progenitor cells (PBPCs) from patients with chronic lymphoproliferative disorders has been analyzed.

STUDY DESIGN AND METHODS

Twenty-two CD34+ cell selections from patients with follicular lymphoma (n = 14), chronic lymphocytic leukemia (n = 6), mantle cell lymphoma (n = 1), and splenic marginal zone lymphoma (n = 1) were performed by use of a magnetic cell selector followed by a negative cell selection step with anti-CD19 monoclonal antibody bound to immunomagnetic beads.

RESULTS

The PBPC components contained median CD34+ cells of 1.24 percent (range, 0.38-3.92%) and CD19+ cells of 1.83 percent (range, 0.06-69.7%). After positive selection (n = 22), 49 percent (range, 16-72%) of CD34+ cells were recovered with a purity of 93 percent (range, 24-99%). The double-positive and -negative selections (n = 20) yielded 57.5 percent of CD34+ cells (range, 33.4-79.4%) with a purity of 95 percent (range, 63-99%). Logarithms of B-cell reduction in the CD34+-cell-enriched B-cell-depleted component had a median value of 3.63 (range, 2.74-4.84 log) and CD19+ and CD5+ cells for chronic lymphocytic leukemia patients with more than 4.56 log (>3.6-5.6 log). Of 13 PBPC components that had a tumor-specific clonal signal, 10 became PCR negative after the double-selection procedure.

CONCLUSION

Combined positive and negative magnetic cell selection achieves a high grade of tumor cell reduction with up to 77 percent of the grafts being negative for tumor-specific clonal signal by PCR analysis. This technique preserves an adequate recovery of progenitor cells able to engraft.

High-dose therapy for indolent lymphoma

Stem-cell transplantation (SCT) has become the treatment of choice for patients with relapsed aggressive non-Hodgkin's lymphoma (NHL). However, the role of SCT in the management of patients with indolent NHL remains controversial. Indolent follicular lymphomas are diseases which are generally incurable with conventional therapy. Although patients can survive for prolonged periods, the median duration of first remission is approximately 3 years, and subsequent remissions are progressively shorter with time. Emerging evidence suggests that high-dose chemotherapy with SCT leads to prolonged disease-free and overall survival in a subset of patients with indolent NHL. However, there is increasing concern regarding the toxicity of SCT, especially the long-term risk of developing myelodysplastic syndrome. It is still unclear as to when this approach should be used. Poorer outcomes have been obtained in heavily pretreated patients but encouraging results are being reported for patients undergoing SCT early during the course of their disease. Investigators are now focusing on how to improve SCT efficacy in order to eradicate minimal residual disease. Many ongoing studies are especially exploring the impact of stem-cell purging and novel ablative regimens combined with allogeneic transplantation.

Kinetics of hemopoietic recovery after peripheral blood stem cell transplantation: impact of stem cell purification and G-CSF

We investigated the role of stem cell purification and G-CSF (early vs. delayed vs. no G-CSF) administration on hemopoietic recovery and supportive care requirements after stem cell transplantation. Thirty-two patients submitted to autologous CD34(+) peripheral blood stem cell transplantation (PBSCT) were studied, and data were compared to patients undergoing unfractionated peripheral blood stem cell transplantation (uPBSCT) matched for age, disease, and conditioning regimen. Except for PMN, hemopoietic recovery was significantly slower and supportive care requirements were significantly higher after CD34(+) PBSCT. Median time to PMN >0.5 x 10(9)/l was 13 days (range 9-27) and 13 d (range 9-23); reticulocytes (Ret) >1% was 14.5 d (range 12-34) and 12 d (range 10-27); high-fluorescence reticulocytes (HFR) >5% was 12 d (range 9-26) and 9 d (range 7-11); platelets >50 x 10(9)/l and >100 x 10(9)/l was 20 d (range 10-240), 12 d (range 9-60) and 33 d (range 15-720), 15 d (range 11-210). When the analysis was performed on subgroups of patients (early/delayed/no G-CSF), early G-CSF significantly promoted PMN recovery (>0.5 x 10(9)/l and >1.0 x 10(9)/l) compared to no G-CSF, without affecting RBCs or platelet recovery. Delayed G-CSF did not improve PMN recovery compared to patients not receiving G-CSF, did not result in a significant reduction of drug requirements, and had a negative impact on erythroid and platelet recovery. In conclusion, these preliminary data suggest that G-CSF is useful if given early after CD34(+) PBSCT. CD34(+) PBSCT may overall require a significant increase of resource utilization that should be outweighed by proven clinical benefit.

Efficacy and safety of CD34-selected and CD19-depleted autografting in multiple myeloma patients: a pilot study

OBJECTIVE

If multiple myeloma patients are to be cured after high-dose treatment supported by autologous stem cell transplantation, grafts must be purged of circulating myeloma cells. Myeloma cells are present in all grafts and have been identified as CD38(++)CD45(-) plasma cells, plasma blasts, and CD19(+) B cells.

MATERIALS AND METHODS

In an attempt to improve the purging strategy, we studied a two-step procedure consisting of CD34(+) enrichment followed by CD19 depletion. This article describes the evaluation of this sequential magnetic microbead selection after 18 procedures in 14 patients.

RESULTS

The processed autografts contained a median CD34 purity of 81% (range 21-99%) and a recovery of 47% (range 15-82%). Flow cytometric analysis documented the expected reduction of CD34(-) B cells and plasma cells, in most cases to a level below the sensitivity of flow cytometry. Real-time reverse transcriptase polymerase chain reaction documented a CD19 mRNA relative reduction to 0.042 (range 0.01-0.21). Allele-specific oligonucleotide IgH primers were designed for five patients. All products were positive for clonal myeloma cells before processing, but only 1 of 5 was negative after the procedure. The clinical outcome after reinfusion of the processed autografts was evaluated by blood cell recovery and found to be within the range expected from engraftment of unmanipulated autografts. One patient who had delayed platelet recovery associated with cytomegalovirus infection recovered after anti-cytomegalovirus treatment.

CONCLUSIONS

This pilot study documented engraftment after reinfusion of CD34-selected and CD19-depleted autografts. However, one patient suffered from unexpected prolonged thrombocytopenia. The efficacy of the procedure was evaluated and reduction of myeloma cells was indicated, with only one autograft free of clonal cells.

Mobilisation of tumour cells along with CD34+ cells to peripheral blood in multiple myeloma

BACKGROUND

Cells belonging to the malignant clone are found in the peripheral blood in myeloma patients. In order to minimise the content of tumour cells in the stem cell product it is crucial to perform stem cell harvest at a time when tumour cells in the peripheral blood are at a minimum.

OBJECTIVE

The aim of the study was to compare the mobilisation kinetics of normal CD34+ cells and myeloma plasma cells during mobilisation with either G-CSF alone or high-dose cyclophosphamide (HDCy) plus G-CSF.

DESIGN AND METHODS

Morning blood samples were drawn each day during mobilisation from start of G-CSF or HDCy and to the end of leukapheresis, and were analysed by flow cytometry for content of CD34+ cells and myeloma plasma cells (CD38+ + CD45-). Tumour cells were also estimated by a patient-specific real-time polymerase chain reaction (PCR) method based on the 5' nuclease TaqMan technology.

RESULTS

Flow cytometry data from 16 patients showed concomitant mobilisation of CD34+ cells and myeloma plasma cells. Seven patients were mobilised twice; first with G-CSF alone and then with HDCy plus G-CSF. There was no difference between the two mobilisation regimens regarding tumour cell mobilisation kinetics. Real-time PCR was performed in one patient and confirmed the mobilisation of tumour cells at the time when CD34+ blood cells were at a maximum.

CONCLUSIONS

Tumour cells are mobilised to the peripheral blood at the same time as CD34+ cells in multiple myeloma patients after priming with both G-CSF alone and HDCy in combination with G-CSF.

CD34+-selected autologous peripheral blood stem cell transplantation conditioned with total body irradiation for malignant lymphoma: increased risk of infectious complications

Although high-dose chemotherapy with autologous peripheral blood stem cell transplantation (autoPBSCT) has been shown or confirmed to be an effective treatment for high-risk and relapsed non-Hodgkin's lymphoma (NHL), relapse after autoPBSCT remains a serious problem. In a clinical trial to overcome relapse, we adopted a treatment plan in which PBSCs purified in vitro to CD34+ cells to deplete tumor cells (CD34+ autoPBSCT), total body irradiation (TBI) of 1200 cGy, and melphalan, 180 mg/m2, were used as a preconditioning regimen. Eighteen patients with relapsed or high-risk NHL participated in the study. This study compared the incidence of complications following CD34+ autoPBSCT preconditioned with the TBI regimen (n = 10): the TBI group; CD34+ autoPBSCT with the non-TBI regimen (n = 8): the non-TBI group; and unselected autoPBSCT with the non-TBI regimen (n = 19): the unselected autoPBSCT control group. After day 30 posttransplantation, 6 of 10 patients treated with the TBI regimen developed 11 infectious complications in total, compared with only 1 of 8 patients treated with the non-TBI regimen and 4 of 19 patients given unselected autoPBSCT. Two fatal complications occurred in the TBI group, but none occurred in the other 2 groups. The CD4+ lymphocyte count at 1 month posttransplantation was significantly lower in the TBI group than in the unselected autoPBSCT group. These findings suggest that the addition of TBI to the preconditioning regimen for CD34+ autoPBSCT is associated with an increased incidence of severe infectious complications after transplantation.

High-dose therapy in patients with Hodgkin's disease: the use of selected CD34(+) cells is as safe as unmanipulated peripheral blood progenitor cells

Register data suggest that patients with Hodgkin's disease (HD) given high-dose therapy (HDT) with peripheral blood progenitor cells (PBPC) have a less favourable prognosis as compared to those given bone marrow as stem cell support. Since this can be due to infusion of tumour cells contaminating the PBPC grafts, we initiated a feasibility study in which PBPC grafts from HD patients were purged by CD34(+) cell enrichment. Controversy exists about whether the use of CD34(+) enriched stem cells leads to a delayed haematological and immune reconstitution. We compared these parameters, including risk of infections and clinical outcome after HDT, in patients with HD given either selected CD34(+) cells or unmanipulated PBPC as stem cell support. From October 1994 to May 2000, 40 HD patients with primary refractory disease or relapse were treated with HDT and supported with either selected CD34(+) cells (n = 21) or unmanipulated PBPC (n = 19) as stem cell support. All patients had chemosensitive disease at the time of transplantation. A median of 5.8 (range 2.7-20.0) vs 4.5 (range 2.3-17.6) x 10(6) CD34(+) cells per kilo were reinfused in the CD34(+) group and PBPC group, respectively. No difference was observed between the two groups with regard to time to haematological engraftment, reconstitution of B cells, CD56(+) cells and T cells at 3 and 12 months and infectious episodes after HDT. Two (5%) treatment-related deaths, one in each group, were observed. The overall survival at 4 years was 86% for the CD34(+)group and 74% for the PBPC group with a median follow-up of 37 months (range 1-61) and 46 months (range 4-82), respectively (P = 0.9). The results of this study demonstrate that the use of CD34(+) cells is safe and has no adverse effects either with respect to haematological, immune reconstitution or to infections after HDT.

Large-scale mobilization and isolation of CD34+ cells from normal donors

We describe collection and purification of peripheral blood CD34+ cells from volunteer, normal donors and allogeneic stem cell donors. A total of 98 aphereses were performed on 68 volunteer donors using peripheral venous access. The mean number of nucleated cells collected was 4.6 x 10(10) which included 1.9 x 10(8) CD34+ cells corresponding to 2.7 x 10(6) CD34+ cells/kg. The number of CD34+ cells collected did not differ between males and females but did correlate with the donor's weight and the total number of nucleated cells collected. The Nexell Isolex 300i cell separator was used to isolate CD34+ cells from 30 of the collections. A mean of 0.36% of the total cells was recovered and included 43 +/- 18% of the CD34+ cells. CD34+ cells represented 85 +/- 11% of the recovered cells. The total number of CD34+ cells recovered was not influenced by the number of nucleated cells placed on the Isolex 300i. The percentage of CD34+ cells recovered was not related to the number of CD34+ cells placed on the Isolex 300i. The purity of the final product was influenced by the number of CD34+ cells but not the total number of nucleated cells. An additional 38 CD34+ cell isolations were performed on normal allogeneic stem cell donors with similar results. These observations further support the safety and feasibility of peripheral blood CD34+ cell collection and purification.

Value of autologous stem cell transplantation with purged bone marrow as first-line therapy for follicular lymphoma with high tumor burden: a GOELAMS phase II study

This prospective phase II study was undertaken to evaluate the efficacy and toxicity of early intensive therapy followed by purged autologous bone marrow transplantation (ABMT) in patients with follicular lymphoma with high tumor burden. All patients received the VCAP regimen (vindesine, cyclophosphamide, doxorubicin and prednisone) as conventional chemotherapy and DHAP as second-line therapy. Twenty-nine consecutive patients were included in the study. Twenty-seven patients were grafted, seven in first complete remission (CR) and 20 in first partial remission (PR). Preparative therapy consisted of cyclophosphamide and total body irradiation (TBI) in all the patients. With a median follow-up of 6 years, the actuarial overall survival is 64% and the actuarial event-free survival is 55%. Two treatment-related early deaths were observed. Eleven patients were informative for serial PCR analysis of minimal residual disease after ABMT: two relapsed, four remained disease-free with PCR positivity and five were disease-free with PCR negativity. These encouraging results lay the basis of future prospective randomized trials comparing autologous stem cell transplantation as front-line treatment with conventional chemotherapy for patients with bad prognostic factors.

Lack of benefit of CD34+ cell selected over non-selected peripheral blood stem cell transplantation in multiple myeloma: results of a single center study

In order to determine the clinical impact of CD34+ cell selected autologous transplantation in multiple myeloma (MM), we have performed a retrospective case-controlled analysis comparing 21 MM patients receiving high-dose melphalan and autologous transplantation with CD34+ peripheral blood stem cells (PBSC) as front-line therapy to 21 control patients receiving unselected products. Case matching was performed using the following criteria: age and beta2-microglobulin at diagnosis and disease status at the time of transplantation. Both cohorts were homogeneous in term of induction treatment and conditioning regimen. Patients were collected for CD34+ selection after priming with G-CSF alone. Significantly fewer CD34+ cells/kg were infused to patients in the selected group as compared to patients in the control group: 2.2 (range 0.5-14.3) vs 9.4 (range 1.1-15) (P < 0.001). The median time to neutrophil recovery > or =0.05 x 10(9)/l was 10 days for the CD34+ group and 9.5 days for the control group (P = 0.357). The median time to platelet recovery > or = 20 x 10(9)/l was 9 days for the CD34+ group and 4.5 days for the control group (P = 0.005). Response rates were comparable in both groups (85.7% in the CD34+ group vs 90.4% in the control group). At 3 years, event-free survival (32% in the CD34+ group vs 39% in the control group) and overall survival (85% in the CD34+ group vs 79% in the control group) were not significantly different. Finally, use of unselected products dramatically reduced the cost of the transplantation procedure. This study shows that CD34+ cell selected autologous transplantation is more expensive than transplantation with unselected products and does not improve the clinical outcome of patients with MM.

Progress in haematopoietic stem cell transplantation for multiple myeloma

High-dose myeloablative treatment followed by autologous haematopoietic stem cell transplantation has significantly improved survival of patients younger than 65 years of age with multiple myeloma as compared with conventional chemotherapy. However, all patients seem to relapse and molecular remissions are rare. Results of allogeneic transplantation, still hampered by high transplant-related mortality, have improved dramatically over the last 5-6 years and this is an option for patients younger than 50-55 years old. The relapse rate is lower than with autologous transplantation and molecular remissions are frequent. Some patients are still in complete haematological remission more the 10 years following transplantation. Autologous transplantation followed by nonmyeloablative allogeneic transplantation is on trial and may be a way to eventually cure a fraction of younger patients with multiple myeloma.

Clinical applications of CD34(+) peripheral blood progenitor cells (PBPC)

Recently, a number of devices have been developed for the positive selection of CD34(+) peripheral blood progenitor cells (PBPC) for clinical use in autologous or allogeneic transplantation. The rationale for CD34(+) selection is based on clinical studies showing a two- to five-log reduction of contaminating tumor cells in patients with breast cancer, multiple myeloma and low-grade lymphoma. In addition, a three- to five-log reduction of T cells can be obtained by CD34(+) selection in both autologous grafts for patients with autoimmune disease resistant to conventional therapy and allogeneic grafts to reduce the incidence and severity of acute graft-versus-host disease. Transplantation of positively selected autologous CD34(+) PBPC results in a rapid and stable neutrophil and platelet engraftment in patients who received an infused dose of at least 2.0 x 10(6) CD34(+) cells/kg. Results from randomized trials suggest that time to engraftment is not different compared to unmanipulated PBPC autografts. However, close monitoring for infectious complications (e.g., cytomegalovirus disease) is required. Allogeneic CD34(+) PBPC have also been successfully transplanted and, using novel technologies, megadoses of purified CD34(+) PBPC can be obtained and used to overcome histocompatibility differences betweeen allogeneic donor and patient resulting in stable engraftment, even in a haploidentical setting. Additional randomized phase III trials are required to determine whether tumor cell purging or lymphocyte depletion by CD34(+) cell selection will have a significant impact on progression-free and overall survival in both autologous and allogeneic transplantation.

In vivo depletion of B cells using a combination of high-dose cytosine arabinoside/mitoxantrone and rituximab for autografting in patients with non-Hodgkin's lymphoma

We performed a pilot study including rituximab (Mabthera; IDEC-C2B8, Hoffmann-La Roche) with a sequential high-dose therapy protocol in 15 patients with follicular and three patients with mantle cell lymphoma and studied the potential of the chemoimmunotherapy to induce depletion of malignant B cells in vivo. Our treatment protocol included induction with three cycles of CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) chemotherapy, followed by peripheral blood stem cell (PBSC) mobilization using high-dose cytosine arabinoside (2 g/m2 every 12 h, days 1 and 2) and mitoxantrone (10 mg/m2, days 2 and 3) (HAM), preceeded by rituximab (375 mg/m2). The proportion of CD19+ B cells in blood and bone marrow decreased from 1.2 +/- 0.4% to 0.13 +/- 0. 1% (P = 0.01) and from 2.7 +/- 0.8% to 0.8 +/- 0.5% (P = 0.03) respectively. The number of t(14;18)-positive cells in blood and bone marrow progressively decreased with treatment, as assessed by the quantitative real-time PCR assay in four patients. Conversion to PCR-negativity was achieved in the peripheral blood (PB) of seven informative patients. Leucaphereses were performed during the granulocyte colony-stimulating factor (G-CSF)-supported leucocyte recovery phase. In 17 of 18 patients, a median of 15.1 x 106 CD34+ cells/kg body weight (BW) could be harvested by a single procedure for enrichment by an immunomagnetic method. Leucapheresis products contained 51.3 +/- 28.8 x 104 CD19+ B cells/kg BW (mean) and were t(14;18) PCR negative in all seven informative patients. These data compare favourably with results obtained in patients treated with the same regimen without rituximab. The high-dose therapy (n = 12 patients), including total body irradiation (14.4 Gy) and cyclophosphamide (200 mg/kg BW), was also preceeded by rituximab. Recovery of neutrophils to > 0.5 x 109/l and of platelets to > 20 x 109/l required a median of 13.5 and 11.5 d (range 11-24 and 9-24 d) respectively. In conclusion, the addition of the CD20 antibody to chemotherapy ensured tumour depletion in vivo and allowed the collection of PBSCs devoid of tumour cells and with conserved engraftment capability.

Prognostic factors for the clinical outcome of patients with follicular lymphoma following high-dose therapy and peripheral blood stem cell transplantation (PBSCT)

This is a report on 111 patients with advanced stage follicular lymphoma who where autografted using PBSC. Seventy patients were enrolled in first remission, whereas 41 were treated in second or higher remission. High-dose therapy consisted of total body irradiation plus cyclophosphamide in 103 patients, while eight patients received BEAM (carmustine, etoposide, cytosine-arabinoside, melphalan). Autografts contained 8.1 +/- 0.6 x 106 CD34+ cells/kg body weight. At a median follow-up of 44.2 months from PBSCT (range 4.9-77.4 months), 93 patients are alive, with a probability of overall and relapse-free survival (RFS) of 83% and 64%, respectively. A significantly higher probability of relapse was associated with male gender, involvement of more than eight lymph node areas, extra-nodal manifestations other than bone marrow and PBSCT performed in second or higher remission. In the latter group of patients, previous radiotherapy was associated with poor prognosis. The relevance of chemosensitivity as a prognostic factor was reflected by a better RFS in patients who had achieved complete remission at the time of PBSC mobilization. In a multivariate analysis, involvement of eight or more lymph nodes and high-dose therapy performed in second or higher remission were independent prognostic factors.

Immune reconstitution after transplantation of autologous peripheral CD34+ cells: analysis of predictive factors and comparison with unselected progenitor transplants

The recovery of lymphocyte count, CD4+ and CD8+ T-cell subsets, natural killer (NK) cells and CD19+ B-cells was evaluated in a cohort of 15 patients receiving autologous CD34+ peripheral blood progenitor cells (PBPCs; group A) for haematological malignancies and in 20 patients transplanted with autologous unselected PBPCs (group B). Lymphocyte count recovered in both patient cohorts, being significantly lower in group A than in group B 1 (P = 0.008) and 2 months (P = 0.0035) after progenitor cell infusion. The repopulation of CD3+ T-cells occurred more rapidly in group B than in group A (P = 0.034 on week 4); CD19+ B-lymphocytes did not return to reference ranges in either group of patients. The count of CD4+ T-lymphocytes remained < 200/microl during the study period in patients transplanted with CD34+ PBPCs, significantly lower than group B levels (P = 0.034 and P = 0.021 on weeks 4 and 8 respectively). CD8+ T-cells increased rapidly in both groups; thus, the CD4 to CD8 ratio was severely reduced. CD4+ and CD8+ T-cells displayed an activated phenotype in both groups of patients, co-expressing the HLA-DR antigen throughout the study period. NK cells followed a similar repopulation kinetics in both study groups, although their expansion was greater in group B than in group A (P = 0.014 on week 4). In the CD34+ group, post-transplant administration of granulocyte colony-stimulating factor predicted a faster lymphocyte recovery in multivariate analysis (P = 0.025); interestingly, the amount of passively transferred lymphocytes correlated inversely with time to achieve a lymphocyte count > 0.5 x 10(9)/l (r = -0.63, P = 0.01). Further investigations are necessary to characterize T-cell competence after transplantation of CD34+ PBPCs.

New anti-cancer therapies, new opportunities for infection

Therapeutic approaches in the practice of haematology/oncology are increasing in complexity. Agents such as the purine analogues and monoclonal antibodies may introduce a new spectrum of infection as a consequence of prolonged/profound lymphoid suppression. The use of high dose therapy with stem cells support is increasing rapidly in clinical practice. Allogeneic transplantation is associated with prolonged immunosuppression and a high potential for transplant-related mortality from infection. This has led to intense interest in strategies aimed at improved prophylaxis and treatment of infective complications. This review aims to summarize recent advances in haematological practice and the effect this has had on opportunistic infections.