Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Bone Marrow Purging”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 955 records · Page 53Linked to original sources
PubMed1999

Synergistic effects of heat and ET-18-OCH3 on membrane expression of hsp70 and lysis of leukemic K562 cells.

We previously reported that cell surface expression of hsp70, the major stress inducible member of the 70-kDa heat shock protein family, is inducible by nonlethal heat as well as by treatment with the membrane-interactive compound alkyl-lysophospholipid 1-octadecyl-2-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3) selectively on human tumor cell lines. Plasma membrane expression of hsp70 increases selectively the sensitivity of tumor cells to lysis and, therefore, might play an important role in the antitumor immune response. Here, we demonstrate that a combined treatment consisting of sublethal heat (41.8 degrees C) and a noncytotoxic concentration of ET-18-OCH3 (25 micrograms/mL) results in a synergistic increase in the amount of cell membrane-bound hsp70 on leukemic K562 cells and on freshly isolated bone marrow of a chronic myelogeneous leukemia (CML) patient, but not on peripheral blood lymphocytes or CD34+ hematopoietic progenitor cells of healthy human individuals. Under these conditions the repopulating capacity of progenitor cells was not influenced. The increased hsp70 membrane expression on leukemic K562 cells results in a significantly increased sensitivity to lysis mediated by natural killer cells. In contrast to leukemic cells, the lysis of peripheral blood lymphocytes and CD34+ progenitor cells that lack expression of hsp70 on their plasma membrane was not negatively influenced by this treatment. A nonspecific disruption of the plasma membrane could be excluded, because treatment with a nontoxic concentration of the detergent Tween20 did not have an influence on hsp70 cell surface expression or on the sensitivity to lysis. Our findings might have further clinical implications with respect to purging of bone marrow from patients suffering from leukemia at sublethal conditions to induce a tumor-selective immune response.

Adult↗
PubMed2004

[Comparison of autologous and allogeneic hematopoietic stem cell transplantation for 140 patients with de novo acute leukemia in first complete remission].

OBJECTIVE: To evaluate the outcome of patients with de novo acute leukemia (AL, no AML-M(3)) in CR(1) undergone autologous hematopoietic stem cell transplantation (auto-HSCT) or HLA-identical sibling allogeneic HSCT (allo-HSCT). METHODS: Forty-six AL patients received allo-HSCT and 94 received auto-HSCT in CR(1). The conditioning regimens mainly consisted of TBICy, BuCy and MAC. Cyclosporine plus methotrexate, or cyclosporine alone, or FK506 alone was used for graft-versus-host disease (GVHD) prophylaxis. Among auto-HSCT group, 39 patients received purged autologous bone marrow and 38 received immunotherapy and/or maintenance chemotherapy after transplant. RESULTS: Myeloid reconstitution was achieved in all patients. After a median of 700 (range, 18 approximately 5563) days follow-up, the probabilities of leukemia-free survival (LFS) at 5 year were not significantly different in these two groups: (51.5 +/- 5.4)% for auto-HSCT group and (52.8 +/- 7.6)% for allo-HSCT group (P > 0.05). There was a lower cumulative relapse incidence (RI) [(26.3 +/- 6.9)% vs. (52.0 +/- 5.5)%, P > 0.05] but a significantly higher cumulative transplant-related mortality (TRM) [(37.6 +/- 7.8% vs. (14.4 +/- 4.1)%, P < 0.05] in the allo-HSCT group than in auto-HSCT group. Among auto-HSCT group, the patients received purged autografts and/or post-transplant therapy had significantly better LFS and lower RI (P < 0.05) than those received unpurged autografts or no post-transplant treatments [5-y LFS: (62.8 +/- 6.8)% and (38.4 +/- 8.4)%; RI: (37.7 +/- 6.8)% and (74.2 +/- 8.7)%, respectively]. CONCLUSION: The long-term LFS of auto-HSCT was comparable to that of allo-HSCT in the management of patients with AL in CR(1), because autograft purging and post-transplant treatment can significantly decrease relapse of auto-HSCT patients and auto-HSCT has lower therapy-related toxicities.

Acute Disease↗
PubMed1994

In vitro purging of clonogenic leukaemic cells from human bone marrow by interferon-gamma-activated monocytes.

With a view to the immunologically mediated purging of autologous bone marrow transplants in acute myeloid leukaemia, the efficacy of cytotoxic monocytes to eradicate leukaemic cells has been studied using clonogenic assays. U937 cells were found to be sensitive to highly purified and interferon-gamma-activated human monocytes whereas HL60 cells were rather resistant as measured in an MTT-based cytotoxicity assay under liquid conditions. A spectrophotometric clonogenic assay measured almost complete inhibition of clonogenic activity for U937 cells at low effector-to-target cell (E/T) ratios of at least 0.1. Limiting dilution analysis detected a 2-3 log10 unit reduction in clonogenic activity. In an experimental mixture of U937 cells with a 20-fold excess of normal bone marrow nuclear cells a maximum 2-log10-unit killing could be measured at E/T = 10. Only at high E/T ratios could a reduction in granulocyte/macrophage-colony-forming units (cfu) be observed with only marginal effects on erythroid cfu and erythroid burst-forming. In conclusion, cytotoxic monocytes are highly potent anti-leukaemic effector cells, as measured in clonogenic assays, that do not compromise normal human progenitors.

Acute Disease↗
PubMed1999

Influence of cytotoxicity enhancers in combination with human serum on the activity of CD22-recombinant ricin A against B cell lines, chronic and acute lymphocytic leukemia cells.

Despite the strong in vitro activity of some immunotoxins (ITs), clinical application did not result in complete cure. The outcome of therapy may be improved by combining ITs with IT-cytotoxicity enhancing agents. We studied the effect of various agents that influence the intracellular routing of ITs on the activity of the anti-B cell IT CD22-recombinant (rec) ricin A. In protein synthesis inhibition assays the carboxylic ionophores monensin and nigericin enhanced the activity of the IT 117- and 382-fold, respectively, against the cell line Daudi, and 81- and 318-fold, respectively, against the cell line Ramos. IT activity to Daudi and Ramos was enhanced to a lesser extent by the lysosomotropic amines chloroquine (14- and 11-fold, respectively) and NH4Cl (nine- and 10-fold, respectively). However, the combination of NH4Cl and chloroquine induced more than an additive effect (145- and 107-fold, respectively). Cytotoxicity was not influenced by brefeldin A, all-trans retinoic acid (ATRA), verapamil and perhexiline maleate. Bacitracin enhanced the IT cytotoxicity in contrast to the other protease inhibitors aprotinin, leupeptin and soybean trypsin inhibitor, albeit enhancement was weak (two-fold). The enhancers exerted only a negligible effect on bone marrow progenitor cells. We recently developed a flow cytometric cytotoxicity assay in which cell elimination can be assessed. In order to detect enhancement in this assay, we used 5 x 10(-11) M IT (approximately the 50% protein synthesis inhibiting dose (ID50)). This concentration killed 41% of the Daudi cells and 42% of the Ramos cells. In the presence of 10 nM monensin the IT killed 74% and 99% and in the presence of 10 nM nigericin 96% and 99% of the Daudi and Ramos cells, respectively. At 10(-8) M, CD22-rec ricin A eliminated malignant cells originating from three patients with B-CLL (0.42 log) and two with B-ALL (0.19 log) patients. Cytotoxicity to malignant cells was enhanced by NH4Cl, chloroquine, monensin and nigericin. The combination of NH4Cl and chloroquine enhanced the activity most effectively (up to 2.06 log). To determine the applicability of the IT in combination with enhancers in vivo we investigated the effect of human serum. Human serum inhibited IT activity which could not be restored by monensin and nigericin because of complete inhibition of these enhancers by serum. In contrast, chloroquine partially restored the activity of CD22-rec ricin A in the presence of human serum. We conclude that monensin, nigericin and the combination of NH4Cl and chloroquine can be used instead of NH4Cl to potentiate CD22-rec ricin A activity in purging autologous bone marrow transplants contaminated with malignant B cells. Chloroquine might be a promising enhancer of CD22-rec ricin A for treating patients in vivo.

Antigens, CD↗
PubMed1997

Minimal residual disease in leukemia in children.

Many chromosomal translocations involved in leukemia have been defined at the molecular level in recent years. In addition to advancing the understanding of pathological mechanisms underlying the transformation process, the cloning and sequencing of the genes altered by the translocations have provided new tools for diagnosis and monitoring of patients. In particular, the polymerase chain reaction (PCR) method yields sensitive and accurate diagnostic and prognostic information. Minimal residual disease (MRD) is not clearly defined. In ALL we define MRD as fewer than 5% blast cells in the bone marrow by conventional cytology and proof of leukemic cells with more sensitive methods. The techniques for detecting MRD are imaging for detection of single leukemic cells in the blood, bone marrow, or other tissues by means of immunocytology or PCR/RT-PCR. Highly sensitive PCR, immunocytology, FACS analysis, or conventional cytology are important tools to use in the process of deciding on appropriate therapy. Detection limits at present are 10(-2) for cytology and FISH, up to 10(-4) for immunological procedures, and 10(-5) to 10(-6) for PCR. But multiple methods also imply the possibility of mistakes (e.g., PCR). The question must be raised what method should be decisive in assessing MRD for evaluating autologous peripheral blood stem cells (PBSC) or autologous bone marrow transplants? Prospective studies will have to answer the question whether MRD should be treated or not and whether purging of bone marrow or PBSC is useful or damaging. When applied, should a positive or a negative immunopurging or a chemotherapeutic purging be used? MRD refers to the organism of the patient as well as to the peripheral blood stem cells and autologous bone marrow that had been taken before myeloablative therapy and kept for retransfusion.

Bone Marrow Transplantation↗
PubMed1988

Cutaneous leucocyte composition after human allogeneic bone marrow transplantation: relationship to marrow purging, histology and clinical rash.

Immunohistological and morphometric techniques were used to study the skin after marrow transplantation with particular reference to the relationship of marrow purging, the presence of a clinical rash and histological changes to leucocyte numbers and phenotype. Recipients of T-cell-depleted marrow showed significant reductions in CD2+, CD4+ and CD8+ T-lymphocytes in the first 22 d after transplantation but not after this time. T-cell numbers in recipients of unpurged marrow were similar to those of normal donors, indicating a rapid repopulation by cells from the graft. Langerhans cells (CD1+ dendritic cells) and macrophages, on the other hand, were present in similar numbers in both groups of patients within the first 22 d; the former in low and the latter in normal numbers. Biopsies exhibiting graft versus host disease showed increases in CD2+, CD4+ and CD8+ T-lymphocytes with significant lowering of the CD4:CD8 ratio. A proportion expressed markers of activation and HNK1+ cells and macrophages were also increased. Biopsies exhibiting epidermal basal abnormalities only (changes identical to graft versus host disease but without detectable leucocyte infiltration on conventional microscopy) showed a minor increase in macrophages and HNK1+ cells but no other leucocyte alterations to suggest a pathogenetic link with graft versus host disease. Langerhans cells were reduced in these biopsies, however, when taken more than 22 d post-transplant, suggesting that the epidermal changes are associated with Langerhans cell damage or repopulation. We were unable to identify any significant alteration in leucocytes in patients with strong clinical evidence of graft versus host disease but with histologically unremarkable biopsies. Although it is possible that perivascular increases in T-cells and expression of activation markers precede the characteristic histological picture of graft versus host disease the time scale is probably too short to allow diagnostic value.

Adolescent↗
PubMed2001

Ex vivo purging of stem cell autografts using cytotoxic cells.

Autologous stem cell transplantation (SCT) is the treatment alternative offered to patients that cannot benefit from allogeneic transplantation due to lack of suitable donor or age limitations. However, the outcome of autologous SCT is largely hindered by the high relapse rate. Two major factors can account for relapse after autologous SCT: the persistence of residual malignant cells resistant to chemo/radiotherapy left either in the body or in the autograft. Therefore, the rationale for purging autografts of residual malignant cells comes from the limitations of conventional high-dose chemo/radiotherapy in achieving a complete eradication of residual tumor cells in the marrow. To date, different purging modalities have been exploited. Immunological methods of purging present the advantage of being non-cross-reactive with conventional chemotherapy. These immunologic methods include depletion using antibody targeting of the malignant cells, ex vivo activation/generation of the autologous cytotoxic cells, in particular that of natural killer/lymphokine-activated killer (NK/LAK) and cytokine-induced killer (CIK) cells, and ex vivo purging of autografts using cytotoxic cell lines. The generation of ex vivo-expanded and activated autologous cytotoxic cells (CTL or NK) has generated increasing interest for the treatment of different malignancies. Unfortunately, the isolation and expansion of these cells have proven to be technically difficult. As an alternative, the use of cytotoxic cell lines as immune effectors has been proposed. The two available human cytotoxic cell lines TALL104 and NK-92 are currently in clinical trials and a number of studies have suggested their effectiveness as an immunotherapeutic agent including for ex vivo purging of autografts.

Bone Marrow Purging↗
PubMed1994

Chronic myelogenous leukemia.

The Ph chromosome, the abnormality characteristic of chronic myelogenous leukemia, was discovered in 1963. However, the events responsible for the pathogenesis and transformation to accelerated and blastic phases are still unknown at the molecular level and are subjects of ongoing research. The positive outcome in a subset of patients with interferon therapy and the potential for cure with bone marrow transplantation have evoked controversy regarding the best approach for different groups of patients according to prognostic characteristics. At the same time, new therapies with promising results are being developed, both in the setting of chemotherapy and biologic therapy and in bone marrow transplantation. Homoharringtonine chemotherapy, the use of matched unrelated donors for bone marrow transplantation, and new modalities of purging for autologous bone marrow transplantation are some examples. Sensitive molecular techniques that allow for the detection of small numbers of bcr-abl-positive hematopoietic cells may provide new means of assessing the results of current and future therapies.

Antibodies, Monoclonal↗
PubMed1993

Autologous bone marrow transplantation after a long first remission for children with recurrent acute lymphoblastic leukemia.

Fifty-one children with acute lymphoblastic leukemia (ALL) in second or subsequent remission after a first remission of at least 24 months underwent purged, autologous bone marrow transplantation (ABMT). Bone marrow was harvested in remission and purged in vitro with monoclonal antibodies specific for leukemia-associated antigens. Ablative chemotherapy included cytarabine, teniposide, and cyclophosphamide followed by total body irradiation. Of the 51 patients treated between November 1980 and June 1991, 5 died of treatment-related complications, 18 relapsed, 1 died of a second tumor at 6.7 years, and 27 remained in continuous complete remission for a median of 39 months (range, 9+ to 124+). Event-free survival (EFS) (+/- SE) at 3 years after ABMT was 53% +/- 7%. Leukemia-free survival (LFS) was 58% +/- 8%. In multivariate analysis, the most significant predictors of EFS were duration of longest pre-ABMT remission and remission duration immediately before ABMT. For LFS, the most significant predictors were cell dose per kilogram of marrow reinfused and duration of longest pre-ABMT remission. We conclude that ABMT for this population is an effective therapy available to the majority of children with relapsed ALL.

Adolescent↗
PubMed1990

Density-gradient separation of autologous bone marrow grafts before ex vivo purging with 4-hydroperoxycyclophosphamide.

We found in previous studies that the cytotoxicity of 4-hydroperoxycyclophosphamide (4-HC) toward normal and malignant cells in autologous bone marrow grafts was modulated by the variable erythrocyte content of the incubation mixture. This affected both the kinetics of engraftment and the probability of leukemic relapse. To decrease this variability in 4-HC cytotoxicity, we initiated a trial of density-gradient separation of the autografts to remove erythrocytes and other mature blood cells before the 4-HC treatment. A series of 64 consecutive patients was studied. Light-density (sp. gr. much less than 1.077 g/ml) cells were isolated in a 2-step procedure by Ficoll-diatrizoate separation of previously isolated buffy-coat cells. Overall cell recovery after buffy-coat and gradient separations was 28.9 +/- 11.7% ( +/- SD). These cells were then treated with 60 micrograms/ml of 4-HC. The erythrocyte content of the incubation mixtures averaged 0.8%, and did not predict percent CFU-GM survival after the 4-HC incubation. The variability in CFU-GM survival after the purge was less than for previous patients who received buffy-coat cells (with erythrocyte contents ranging from 4-22%) treated with 100 micrograms/ml of 4-HC, indicating that a more uniform purge was achieved. Although the selected dose of 4-HC (60 micrograms/ml) yielded a lower CFU-GM survival, the kinetics of engraftment did not significantly differ between the recipients of light-density or buffy-coat cells. No patient required use of a 'backup' graft because of engraftment failure.

Adolescent↗
PubMed1995

Purging of peripheral blood stem cell grafts.

The shortage of HLA-matched sibling donors for bone marrow transplant patients has stimulated interest in the use of alternative donors. As a result, there has been a dramatic increase in the use of autologous marrow transplantation, which avoids the complications of graft-versus-host disease, but may deprive the patient of a potentially beneficial graft-versus-disease response and runs the risk of returning occult tumor cells with the graft. There is increasing evidence that these cells may be associated with disease relapse post-transplant, and many methods have been developed for their removal ex vivo. Combinations of negative and positive selection may achieve elimination of tumor cells to the limits of detection of the most sensitive assays currently available. The marked trend toward the use of autologous grafts derived from blood rather than marrow has raised the question as to whether peripheral blood stem cell (PBSC) preparations should be purged of tumor. Data indicate that these grafts generally contain a lower tumor burden, although the stem cell mobilization procedure may recruit tumor cells into the peripheral circulation. Enrichment of CD34+ cells from apheresis products appears, at present, to be less efficient than from marrow and provides at best about a 2-3 log depletion of tumor. This has prompted proposals to follow positive selection by a small-scale purging procedure. Technical issues, such as preprocessing and pooling of collections prior to purging, remain to be addressed. Ultimately, the development of successful purging procedures for PBSC grafts will simply reemphasize the necessity of improving the efficacy of high-dose therapy.

Bone Marrow Purging↗
PubMed1990

[Purge of malignant cells from bone marrow by hematoporphyrin derivatives and light exposure in vitro].

During autologous bone marrow graft in treatment of malignant diseases, it is critical to purge malignant cells from the marrow. In the present study, the sensitivity to photodynamic inactivation of 3 leukemic cell lines was compared with their counterpart normal hematopoietic cells. After mouse leukemic L1210 cells were treated with a preparation of hematoporphyrin derivatives, YHpD, 10 micrograms/ml for 1 h and irradiated with black light (peak wavelength 395 nm, light intensity 0.6 mW/cm2) for 5 min, the survival rate of clonogenic cells decreased to less than 10%, while that of bone marrow granulocyte-macrophage progenitor cells (CFU-GM) in DBA/2 mice remained at nearly normal level (greater than 80%). Similar results were obtained when human leukemic HL-60 cells were compared to human CFU-GM and mouse leukemic L615 cells to CFU-GM in 615 strain mice. It is suggested that hematoporphyrin photoradiation may be useful for selectivity killing leukemic cells in bone marrow.

Animals↗
PubMed1997

[Successful high-dose chemotherapy combined with autologous bone marrow transplantation in a case of refractory follicular lymphoma].

A 34-year-old patient with follicular lymphoma who was treated with CHOP followed by COPP for 3 years, became resistant to treatment in December 1993. Histological findings and surface markers of cervical lymph node cells revealed no change from previous findings. Tumor cell involvement of bone marrow was also observed by molecular analysis of DNA fragments with bcl-2 oncogene and J-H gene probes. Following 2 courses of salvage chemotherapy with NOAC-M regimen (novantrone, cytarabine and methylprednisolone), There was an 88% reduction of tumor mass on computed tomographic findings. Through the use of polymerase chain reaction analysis of residual cells with the bcl-2 translocation, we confirmed the in vivo purging of tumor cells from bone marrow and we harvested marrow cells for autologous transplantation. After high-dose chemotherapy (HDC) with ranimustine, cisplatin, etoposide and cyclophosphamide followed by bone marrow transplantation (BMT), complete remission was achieved. The patient has survived for 16 months and remains disease free. The standard chemotherapy regimen for advanced low grade non-Hodgkin's lymphoma has not yet been defined. Although we must follow this patient carefully to determine the effect of HDC with BMT for a long time, this seems to be an effective complementary treatment for patients responding to conventional salvage regimens.

Adult↗
PubMed2000

Targeting of cancer cells with monoclonal antibodies specific for C3b(i).

PURPOSE: The goal of this research is to determine the feasibility of an immunotherapeutic approach based on the use of monoclonal antibodies (mAb) to target complement activation fragments on opsonized cancer cells. METHODS: We investigated whether treatment of LNCaP and C4-2 human prostate cancer cell lines with normal human serum would allow for deposition of sufficient amounts of the complement-activation protein C3b and its fragments [collectively referred to as C3b(i)] such that these proteins could serve as cancer-cell-associated antigens for targeting by mAb. Radioimmunoassays, flow cytometry, and magnetic purging with specific immunomagnetic beads were used for the analyses. RESULTS: In vitro opsonization of human prostate cancer cells with normal human serum resulted in deposition of C3b(i) in sufficient quantity (approx. 100,000 molecules/cell) for the cells to be targeted in a variety of protocols. We found that 51Cr-labeled and C3b(i)-opsonized cancer cells could be specifically purged at high efficiency (95%-99%) using anti-C3b(i) mAb covalently coupled to magnetic beads. Flow-cytometry experiments indicated that most normal white cells were not removed under similar conditions. Opsonization of cancer cells with sera from men with prostate cancer led to lower levels of cell-associated IgM and, subsequently, lower amounts of C3b(i) deposited than in normal subjects. Prototype experiments suggested that this deficiency could be corrected by addition of IgM from normal donor plasma. CONCLUSION: mAb directed against complement-activation products may provide new opportunities to deliver diagnostic and therapeutic agents selectively to cancer cells and tumor deposits. These opportunities may include ex vivo purging of C3b(i)-opsonized cancer cells prior to autologous bone marrow or stem cell transplantation.

Adenocarcinoma↗