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PubMed1993

Loss of long-term repopulating ability in long-term bone marrow culture.

We have studied the maintenance of stem cells with long-term multilineage repopulating ability from murine bone marrow, cultured on a pre-established bone marrow-derived stromal cell layer, both in a qualitative and quantitative way. Female bone marrow cells were cultured for a period of 1-4 weeks and compared with uncultured cells for their ability to establish and maintain a level of 50% chimerism in a sex-mismatched bone marrow transplantation model. Chimerism was determined in nucleated cells using fluorescence in situ hybridization with a murine Y-chromosome-specific probe. We observed a rapid decline in the ability of cultured marrow cells to repopulate the blood, bone marrow, spleen, and thymus of sublethally irradiated male recipients. After 4 weeks of culture only 5% of the long-term repopulating ability of the inoculated bone marrow cells remained. The remaining long-term repopulating cells, however, had similar qualities to establish and maintain long-term engraftment compared to fresh bone marrow, as judged from their ability to give stable chimerism over a period of 6 months. These observations are relevant for the therapeutic applications of long-term bone marrow cultures in purging protocols prior to autologous bone marrow transplantation of acute and chronic myeloid leukemic patients, and for the use of long-term marrow cultures when introducing foreign genetic material in hematopoietic stem cells.

Animals↗
PubMed1999

Ex vivo pharmacological purging of leukapheresis collections with nitrogen mustard: amifostine pretreatment improves both early and late peripheral blood progenitor cell recovery.

Ex vivo pharmacological purging of bone marrow has been used to eliminate clonogenic tumor cells contaminating the autograft and potentially responsible of relapse. A considerable improvement of pharmacological purging would be achieved only if normal marrow progenitor cells could be selectively protected by the cytotoxicity of these agents. Amifostine (WR-2721; Ethyol), a phosphorylated aminothiol compound, has been shown to have this property both in vivo and in vitro. We describe here, an experimental model for ex vivo purging of peripheral blood progenitor cell (PBPC) collections based on the combination of 3 mg/ml of amifostine and the alkylating agent nitrogen mustard. Amifostine pretreatment resulted in a statistically significant protection of normal late and early progenitor cells. Under the same experimental conditions, we observed a 4-6 log reduction of contaminating leukemic cells (i.e., K-562 and CEM) and in contrast to the protection of normal peripheral blood progenitor cells, preincubation of contaminating K-562 or CEM with amifostine did not significantly alter the LD95 nitrogen mustard concentration. Moreover, when we tested fresh human leukemia progenitor cells, amifostine pretreatment sensitized the leukemic cells to the cytotoxic effects of NM.

Amifostine↗
PubMed1993

Comparison of progenitor cell concentration techniques: continuous flow separation versus density-gradient isolation.

Bone marrow harvests were processed using two techniques; 20 mononuclear cell concentrations (MNC) were prepared on the COBE Spectra and compared to 10 light-density cell fractions isolated using the COBE 2991. Both procedures recovered essentially the same percentage of nucleated cells (22 versus 21%) and gave progenitor cell recoveries of 132 and 100% of the CFU-GM and 101 and 104% of the CD34+ cells in the MNC and light-density products, respectively. The advantage of the Spectra MNC concentrate is that it was prepared with reagents approved for injection by the Food and Drug Administration. However, the average hematocrit on the MNC concentrate was 4%, while it was unmeasurable in the light-density cell fractions. This difference is significant only when bone marrows require purging with 4-hydroperoxycyclophosphamide or erythrocytes otherwise interfere with processing. The Spectra procedure recovered a larger percentage of MNC cells and had less contamination with mature granulocytes than did the density-gradient technique. When erythrocytes do not affect the bone marrow processing protocol, a Spectra MNC concentrate is a safe substitute for a light-density cell preparation.

Adult↗
PubMed2004

Autologous bone marrow transplantation for marginal zone non-Hodgkin's lymphoma.

The marginal zone non-Hodgkin's lymphomas are a recently defined group of related low-grade B cell malignancies whose natural history is heterogeneous. The optimal therapy is often unclear, particularly for the subset of patients with disseminated disease that behaves aggressively. We have retrospectively analyzed the outcomes of 11 patients with chemosensitive but disseminated marginal zone lymphomas who underwent uniform conditioning with cyclophosphamide and total body irradiation followed by bone marrow transplantation (BMT) with anti-B cell monoclonal antibody-purged autologous bone marrow between January 1994 and September 1999. All patients had stage IV disease and received multiple chemotherapy regimens prior to autologous BMT. Only 36% were in complete remission at the time of bone marrow harvest, and 36% had overt bone marrow infiltration at that time. Two treatment-related deaths occurred between 100 days and 6 months. Three patients relapsed and died of disease. One patient developed and died of myelodysplasia. Five patients remain in continuous complete remission at a median follow-up of 52 months (45%). The median progression-free survival for these patients was 56 months, with median overall survival 58 months. The only significant predictor of disease-free and overall survival was age at the time of transplant; no patient under 45 at the time of transplant has relapsed or died of any cause (P = 0.003). Outcomes of autologous BMT in patients with disseminated marginal zone NHL are similar to those in follicular NHL, and suggest that certain patients may experience prolonged disease-free survival.

Adult↗
PubMed1997

Bone marrow transplantation in first remission.

The allogeneic bone marrow transplant experience for acute myeloid leukemia (AML) is broader than that for acute lymphocytic leukemia (ALL). However, data describing disease-free survival in AML in first remission in the range of 40% to 65% are almost identical to the data from larger studies of ALL in first remission. Similarly, the published allogeneic transplant data for ALL in second remission are comparable to those in the AML experience. The efficacy of autologous stem-cell transplantation for ALL, while promising, remains unproven in first remission, and larger multicenter studies are underway to answer this question. Until prospective randomized trials of bone marrow or peripheral-blood stem-cell purging have been performed, a conclusion that ex vivo bone marrow transplantation is of clinical benefit for any patient with ALL will be impossible. Such studies will be difficult to conduct and, in an autologous setting, should include genetic marking to help determine whether reinfused leukemic cells will lead to relapse.

Bone Marrow Purging↗
PubMed1994

Long-term culture and molecular biological studies highlight differences in relative BCR-ABL expression levels in the peripheral blood and bone marrow of a patient with chronic granulocytic leukaemia.

A patient with accelerating Ph+ve chronic granulocytic leukaemia (CGL) was considered for autologous BMT using marrow 'purged' by 4 weeks long-term culture (LTC). Efficacy of purging was determined using reverse transcriptase PCR for BCR-ABL mRNA transcripts b2a2 and b3a2. Peripheral blood and bone marrow were compared. Three observations emerged: (i) the initial b2a2:b3a2 ratios for unmanipulated blood and marrow were different with values of 9:1 and 2:1 respectively; (ii) both transcripts were successfully 'purged' with LTC of blood but not marrow; and (iii) LTC of marrow caused a transient increase in relative levels of b3a2 mRNA and a corresponding reduction in the b2a2 signal. This is the first case where such differences have been demonstrated in association with LTC.

Bone Marrow↗
PubMed1995

In vitro purging with BCR-ABL antisense oligodeoxynucleotides does not prevent haematologic reconstitution after autologous bone marrow transplantation.

We treated a patient with chronic myeloid leukaemia in accelerated phase with autologous bone marrow transplantation. Before reinfusion, cells were purged in vitro with a 26-mer phosphorothioate antisense oligodeoxynucleotide specific for the B2A2 junction. Incubation with antisense oligodeoxynucleotides produced a 24 and 41% reduction of CFU-GM and CD34+ cells, respectively. However, an in vitro test previously performed as a screening for patient inclusion in this procedure, revealed a 38 and 75% reduction of colony formation after 24-h and 168-h incubation, respectively. The patient showed bone marrow engraftment 15 days after reinfusion and haematological reconstitution after 17 and 25 days for platelets and neutrophils, respectively. Using fluorescence in situ hybridization in interphase nuclei, we demonstrated the presence of a proportion of Ph-negative cells in repeated controls after the autograft. The patient is now in unmaintained complete haematological remission 9 months after the autograft.

Antigens, CD↗
PubMedDate not supplied

Effect of heat-pretreatment on interleukin-2-activated killer cells for in vitro purging.

OBJECTIVE: Lymphokine-activated killer activity is effective in purging residual malignant cells from autologous bone marrow (BM) or leukapheresis collections for peripheral blood progenitor cells (PBPC). In this study, the effect of additional heat pretreatment on IL-2-activated cytotoxicity was examined. METHODS: Nonadherent mononuclear cells from peripheral blood (PB), PBPC collections or BM were exposed to the desired temperature for 1 h, and successively cultured for 7 days in the presence of 1,000 units/ml of recombinant human interleukin-2 (IL-2). Cytotoxicity of IL-2-activated cells was determined by flow cytometry, using PKH-26-labelled K-562 or Raji target cells, and the cell surface antigens were also analyzed. RESULTS: IL-2-activated cells from all specimens showed a distinct generation of cytotoxic activities. The activities were significantly decreased by heat at 42 degrees C, but not changed by heat pretreatment at 40 degrees C. In the surface expression of IL-2-activated cells, the increase of CD56+ cells from PB, PBPC collections and the decrease of CD28 cells from PBPC collections were shown to be significant (p < 0.05), but these changes were not found when the cells were heat-pretreated at 42 degrees C. DISCUSSION: These results suggested that a tumor-killing therapeutic temperature (> or =42 degrees C) may lead to a disadvantage in posttransplantation immunity, and that this reduction of IL-2-activated cytotoxicity may partly be due to a lack of the enhancement of CD56+ cells or the reduction of CD28+ cells.

Antigens, CD↗
PubMed1993

Selective killing of murine leukemic cells by adenosine triphosphate (ATP): a study of the value of autologous bone marrow transplantation.

To assess the value of adenosine triphosphate (ATP) for ex vivo purging of leukemic cells in autologous bone marrow transplantation, its biological effects on the murine leukemic cell lines (WEHI3B and L1210) and normal murine bone marrow hemopoietic stem cells (CFU-C and CFU-S) were studied. After treatment with 4 mM of ATP for 6 h, the number of viable WEHI3B cells decreased to less than 0.1% of that of the control. Furthermore, 3H-thymidine incorporations were also completely inhibited in both WEHI3B cells and L1210 cells. These phenomena were related to the concentration and exposure period of ATP. Treatment of bone marrow mononuclear cells with ATP under the same condition reduced the number of CFU-C, day 9 CFU-S and day 12 CFU-S to only 58.5 +/- 8.7%, 92.6 +/- 8.2% and 83.5 +/- 28.5%, respectively, with no change in the number of marrow nucleated cells. Although the effect of ATP is not entirely specific to leukemic cells, these findings provide evidence that ATP is useful for purging residual tumor cells in autologous bone marrow transplantation.

Adenosine Triphosphate↗
PubMed1992

Use of etoposide in combination with cyclosporin for purging multidrug-resistant leukemic cells from bone marrow in a mouse model.

Cyclosporin (CsA) is a potent modulator of multidrug resistance (MDR) and has been combined with etoposide (VP-16) to purge MDR leukemic cells from human bone marrow (BM) in vitro. We studied the feasibility of this approach in an in vivo model for autologous BM transplantation using the murine leukemia cell line P388 and its MDR variant P388/ADR. Colony-forming assays with 2-h drug exposure revealed a tumor selectivity of VP-16 for P388 cells compared to normal murine marrow granulocyte-macrophage colony-forming units (CFU-GM), whereas P388/ADR cells were resistant to VP-16. Simultaneous incubation with CsA restored sensitivity in these cells. Almost 4 logs of cell kill were achieved by treating P388/ADR cells with 60 microM VP-16 plus 2.5 microM CsA (combination A) or 40 microM VP-16 plus 10 microM CsA (combination B), whereas there was a 2.5-log reduction of CFU-GM at these doses. Even though the myelotoxicity of VP-16 was increased by the addition of CsA, this effect was nonspecific as shown by a similar chemosensitization in sensitive P388 as well as in P388/VP 2.5 cells, an atypical MDR variant lacking P-glycoprotein. In vivo experiments addressed the ability of BM treated with VP-16 and CsA to rescue lethally irradiated mice and to purge leukemic cells. In total, 1/14 lethally irradiated mice died due to sepsis within 10 days after receiving 15 x 10(6) BM cells treated ex vivo with combination A in contrast to 1/4 for combination B. All 16 surviving animals demonstrated long-term engraftment. When simulated remission marrow contaminated with 0.1% P388/ADR was purged with VP-16 (60 microM) or CsA (2.5 microM) alone, all mice died from leukemia before day 16 after transplantation (median 14.3 and 12.2 days). In contrast, nine of ten animals receiving similar marrow purged with combination A survived > 60 days without any evidence of disease (p < 0.01). We conclude that combining VP-16 and CsA was effective in purging MDR leukemia cells from transplanted BM in this murine model.

Animals↗
PubMed2003

[FasL-cDNA transfected into mouse bone marrow cells ex vivo to prevent graft versus host disease].

To explore the new approach to prevent graft versus host disease (GVHD) by purging ex vivo T lymphocytes of bone marrow graft through Fas-FasL way, FasL-cDNA was transfected into BALB/c mouse bon e marrow cells by liposome ex vivo. The transfected cells were cultured together with BAC (BALB/c x C57BL/6) mouse bone marrow graft. The mixing bone marrow graft was infused into BALB/c mouse recipients after 60Co-gamma irradiation. The mortality, manifestation and pathologic change of GVHD in recipient mice were observed. The CFU-S and Y chromosome from donor mice were detected. The results showed that compared with control group, the mortality in 60 days of the recipients in the experimental group decreased (20% vs 70%, P < 0.01) and the morbidity of GVHD lowered (40% vs 100%, P < 0.01). The CFU-S counts for all groups were at normal level on 20 days after transplantation. The Y chromosome from donor mice was discovered in 70% bone marrow nucleated cells of recipient mice survived over 2 months in the experimental group. It is concluded that mFasL-cDNA transfected mouse bone marrow cells prevent GVHD after culturing together with bone marrow graft, and accelerate hematopoietic reconstitution in recipient mice.

Animals↗
PubMed1993

[Hematopoietic growth factor (GM-CSF) after autologous bone marrow transplantation. A randomized, double-blind, multicenter study in 91 cases of non-Hodgkin's malignant lymphomas].

To a great extent, the risks of autologous bone marrow transplantation are related to neutropenia. Although the efficacy of the recombinant human granulocyte-macrophage colony-stimulating factor (rhu GM-CSF) on neutrophil recovery has appeared in numerous open trials, only a few randomized studies have hitherto been published. Ninety-one patients with non-Hodgkin's malignant lymphoma treated with ablative chemotherapy followed by purged or unpurged bone marrow transplantation were entered in a placebo-controlled, double-blind randomized study; 44 patients received GM-CSF (E. coli) in doses of 250 micrograms/m2/day, and 47 received a placebo. Treatment was administered daily as continuous infusion started on the day of transplantation and pursued until the absolute number of neutrophils reached 0.5 x 10(9)/l during 7 days or, if this failed, during 30 days. The median time of neutrophil recovery was 14 days in patients on rhu GM-CSF and 21 days in patients on placebo (P < 0.0001). Patients who received a mafosfamide-purged bone marrow also had a rapid neutrophil recovery (median: 16 days versus 20.5 days; P = 0.013). The stay in hospital was shorter in the rhu GM-CSF group (median: 23 days versus 28 days; P < 0.05). No significant difference in the number of days with fever, infections, antibiotics administered and overall survival was detected between the two groups. The main toxicity ascribable to rhu GM-CSF was a capillary leakage syndrome found in 3 patients. Thus, after purged or unpurged autologous bone marrow transplantation rhu GM-CSF significantly reduces the duration of both neutropenia and hospital stay.

Adolescent↗
PubMed1992

Bone marrows of non-Hodgkin's lymphoma patients with a bcl-2 translocation can be purged of polymerase chain reaction-detectable lymphoma cells using monoclonal antibodies and immunomagnetic bead depletion.

Using the extremely sensitive technique of polymerase chain reaction (PCR) to detect the bcl-2 translocation, only 50% of bone marrows could be purged of PCR-detectable lymphoma cells using a cocktail of three anti-B-cell monoclonal antibodies (MoAbs) and complement-mediated lysis. This observation is of clinical importance because those patients whose reinfused marrows harbored residual lymphoma cells showed a significantly increased incidence of relapse. To improve purging, we used PCR detection of the bcl-2 translocation to compare the efficiency of complement-mediated lysis with immunomagnetic bead depletion. Using either a three or a four MoAb cocktail followed by immunomagnetic bead depletion, all PCR-detectable cells were purged after three cycles of treatment. In these same patient samples, treatment with three MoAbs and complement purged only 11 of the 25 (44%) samples. The addition of a fourth MoAb followed by complement lysis purged the marrows of only an additional five patients. Immunomagnetic bead depletion was specific because there was no loss of committed myeloid progenitor cells. The above results suggest that immunomagnetic bead depletion of the harvested marrow will likely be superior to our previous method of purging and the lack of nonspecific toxicity to myeloid progenitor cells predicts that it will not impair engraftment. This methodology will now be used to determine whether the reinfusion of lymphoma free marrow affects the incidence of relapse after autologous bone marrow transplantation.

Antibodies, Monoclonal↗
PubMed1992

Autologous bone marrow transplantation in children with acute lymphoblastic leukemia.

We report 25 children with acute lymphoblastic leukemia (ALL) treated with purged autologous bone marrow transplantation (ABMT) at a single center. Two children with high-risk ALL were transplanted in first remission and 23 with relapsing ALL were transplanted in second (n = 21) or third (n = 2) remission. There was no procedure-related mortality. The median time to engraftment (i.e. to reach a polymorphonuclear cell count of 0.5 x 10(9)/l) was 25 days (range 16-45 days). Seven children relapsed, four within five months after ABMT: 18 of 25 children (72%) are in continuous complete remission after a median follow-up period of 50 months (range 5-71 months). The predicted long-term disease-free survival is 65% in the whole group and 61% in those transplanted after relapse. Relapse-free children returned to normal activities within three months after ABMT. The major side effects were development of cataract and gonadal insufficiency. We consider the results promising, but our data do not allow comparison with results reported from treatment with chemotherapy alone, since some of our patients were referred from other centers and represent a selected patient group. Long-term follow-up of well-defined patient populations is necessary to evaluate the effect of ABMT.

Adolescent↗
PubMed1990

The role of bone marrow transplantation in the non-Hodgkin's lymphomas.

In a significant fraction of patients with NHL, disease develops that is resistant to conventional chemotherapy. Experience using high-dose chemotherapy, with or without TBI, and BMT is expanding. Remissions can be achieved in many patients with refractory NHL in particular those patients with tumors that are still chemosensitive. High-dose chemoradiotherapy regimens are toxic and require extensive supportive care. Relapse frequently occurs in areas of previous disease, suggesting failure of the conditioning regimen rather than that an infusion of occult tumor cells in the autologous bone marrow had occurred. Thus, the role of marrow purging in this therapy needs to be further evaluated and compared with findings involving nonpurged marrow reinfusion. It is also important to evaluate the effects of more vigorous attempts at cytoreduction of bulky disease prior to high-dose therapy and BMT. Potential areas for development include the use of this modality as intensification therapy following conventional therapy in patients with intermediate or high-grade NHL with poor prognostic features. Toxicity can be decreased and efficacy increased only if therapy is administered to patients who have not been heavily pretreated and who have lower tumor burden and a good performance status. The role of high-dose chemotherapy and BMT in the nodular lymphomas is not known at this point and requires further investigation. Finally, high-dose therapy with BMT has a definite role in salvaging patients with malignant lymphomas. Many issues need to be resolved, including (1) the optimal timing of this approach, (2) the optimal conditioning regimen, and (3) the need for purging autologous bone marrow prior to reinfusion. The past 10 years have led to significant gains. During the next 10 years, it may be possible to refine this therapy and find solutions to the above issues.

Antineoplastic Agents↗
PubMed1990

Application of target-specific drug immunoconjugates to experimental bone marrow replacement therapy in mice.

Immunoconjugates whose cytotoxic component consists of a phytopeptide are often used as purging agents in bone marrow replacement therapy. Less popular are drug immunoconjugates containing a small molecular weight cytotoxic drug attached to the target-specific conjugand via an appropriate spacer molecule. High target specificity, resistance of the drug to intralysosomal proteases and, once cleaved from the spacer, ready exist of the drug from the lysosome are among the advantages drug immunoconjugates hold over phytotoxin immunoconjugates. The cytotoxic drug daunomycin attached via an acid-sensitive spacer to monoclonal antibody of appropriate specificity was shown to purge murine bone marrow of contaminating tumor cells without affecting its hematopoietic potential. Lethally irradiated mice reconstituted with syngeneic bone marrow from which contaminating lymphoma cells had been removed survived indefinitely. Furthermore, lymphoma-bearing mice, provided they were sufficiently irradiated to eliminate tumor cells in situ, were successfully reconstituted with fully allogeneic bone marrow from which potentially graft-versus-host-reactive T-cells had been purged.

Animals↗