Phase III trial of bortezomib, cyclophosphamide and dexamethasone (VCD) versus bortezomib, doxorubicin and dexamethasone (PAd) in newly diagnosed myeloma.

We aimed at demonstrating non-inferiority of bortezomib/cyclophosphamide/dexamethasone (VCD) compared to bortezomib/doxorubicin/dexamethasone (PAd) induction therapy with respect to very good partial response rates or better (⩾VGPR) in 504 newly diagnosed, transplant-eligible multiple myeloma patients. VCD was found to be non-inferior to PAd with respect to ⩾VGPR rates (37.0 versus 34.3%, P=0.001). The rates of progressive disease (PD) were 0.4% (VCD) versus 4.8% (PAd; P=0.003). In the PAd arm, 11 of 12 patients with PD had either renal impairment (creatinine ⩾2 mg/dl) at diagnosis or the cytogenetic abnormality gain 1q21, whereas no PD was observed in these subgroups in the VCD arm. Leukocytopenia/neutropenia (⩾3°) occurred more frequently in the VCD arm (35.2% versus 11.3%, P<0.001). Neuropathy rates (⩾2°) were higher in the PAd group (14.9 versus 8.4%, P=0.03). Serious adverse events, both overall and those related to thromboembolic events, were higher in the PAd group (32.7 versus 24.0%, P=0.04 and 2.8 versus 0.4%, P=0.04). Stem cell collection was not impeded by VCD. VCD is as effective as PAd in terms of achieving ⩾VGPR rates with fewer PD and has a favorable toxicity profile. Therefore, VCD is preferable to PAd as induction therapy.

Enhanced antileukemic activity of allogeneic peripheral blood progenitor cell transplants following donor treatment with the combination of granulocyte colony-stimulating factor (G-CSF) and stem cell factor (SCF) in a murine transplantation model.

Allogeneic peripheral blood progenitor cells (PBPCs) have mostly been mobilized by granulocyte colony-stimulating factor (G-CSF). There is neither clinical nor experimental data available addressing the question if other hematopoietic growth factors or combinations thereof might influence engraftment, graft-versus-host disease (GvHD), and graft-versus-leukemia (GvL) effects after allogeneic peripheral blood progenitor cell transplantation (PBPCT). We used a murine model to investigate these parameters after transplantation of PBPCs mobilized with G-CSF and SCF either alone or in combination. Treatment of splenectomized DBA and Balb/c mice with 250 microg/kg/day G-CSF for 5 days resulted in an increase of CFU-gm from 0 to 53/microl. The highest progenitor cell numbers (147/microl) were observed after treatment with 100 microg/kg/day SCF administered in conjunction with G-SCF. No differences were detected with regard to the number of T cells (CD3+), T cell subsets (CD4+, CD8+), B cells (CD19+) and NK cells (NK1.1+) in PBPC grafts mobilized by G-CSF plus SCF compared to those mobilized with G-CSF alone. The antileukemic activity of syngeneic and MHC-identical allogeneic PBPC grafts was investigated in lethally irradiated Balb/c mice bearing the B-lymphatic leukemia cell line A20. In this model, PBPCs mobilized by G-CSF plus SCF exerted a significantly higher antileukemic activity compared to grafts mobilized by G-CSF alone (94 vs 71% freedom from leukemia at day 100, P<0.05). The antileukemic effect was lowest after BMT (38% freedom from leukemia). Since significant differences in the incidence of lethal GvHD were not observed, improved GVL-activity resulted in superior overall survival. Our data demonstrate that the utilization of specific hematopoietic growth factors not only improve the yield of hematopoietic progenitor cells but can also significantly enhance the immunotherapeutic potential of allografts.

Idiotype protein-pulsed dendritic cells produce strong anti-myeloma effects after syngeneic stem cell transplantation in mice.

Dendritic cell (DC) vaccination represents an interesting immunotherapeutic option in the treatment of several malignancies. In multiple myeloma (MM) patients, vaccination with autologous idiotype (Id) protein-pulsed DC is feasible, but their antitumoral effectiveness was rather limited. To improve the therapeutic potential of DC therapy, we studied the immunological effects of syngeneic peripheral blood stem cell transplantation (PBSCT) given in conjunction with Id-loaded DC. Balb/c mice were inoculated i.p. with 5 x 10(5) of HOPC myeloma cells (Balb/c origin). Animals were immunized with three injections of 5 x 10(5) DC pulsed with the IgG2a(HOPC) or with a control immunoglobulin (Ig(control)). Some experimental groups of myeloma-bearing animals received total body irradiation (7.5 Gy) and a subsequent transplant of 2 x 10(7)syngeneic peripheral blood progenitor cells (PBPC) followed by DC therapy beginning at day 10 post transplant. Animals receiving DC therapy or syngeneic PBPCT alone neither induce long-term survival nor tumor-specific CTL reactivity in vitro. In marked contrast, combination of syngeneic PBPC transplantation and subsequent DC therapy resulted in 78% survival after a follow-up of 180 days. In addition, this treatment modality conferred a generation of Id peptide-specific CD8-mediated T cell reactivity. These data provide a rationale for DC-based vaccination in multiple myeloma patients administered post syngeneic transplantation.

Activation of natural killer cells with interleukin 2 (IL-2) and IL-12 increases perforin binding and subsequent lysis of tumour cells.

Natural killer (NK) cells can lyse a variety of different tumour cells by exocytosis of perforin, subsequent binding of perforin to the target cell membrane and formation of lytic pores. Some tumour cells, however, are resistant to cellular cytotoxicity. Using the NK-resistant tumour cell lines ML-2, MONOMAC-1, RPMI and L540Cy, we demonstrated that activation of NK cells with interleukin 2 (IL-2) and IL-12 resulted in significant lysis of these tumour targets. To investigate the underlying mechanisms, we isolated the cytotoxic granules from non-activated and IL-2-/IL-12-activated NK cells and compared the killing of K562 leukaemia cells (sensitive to NK cell-mediated lysis) and ML-2 leukaemia cells (resistant to NK cell-mediated lysis). In contrast to K562 cells, which were easily killed by NK-cell granules, ML-2 cells were resistant to granules from non-activated NK cells. However, granules from NK cells activated with IL-2 and IL-12 were able to induce significant tumour cell lysis. Cell death of both K562 and ML-2 cells by granules from activated NK cells was completely blocked by anti-perforin antibodies, indicating that perforin mainly accounts for the lysis induced by NK granules. Comparing granules from non-activated and IL-2-/IL-12-activated NK cells, the increased cell death of ML-2 cells was caused by an improved binding of perforin to the target cell membrane. Functional assays, however, indicated that the differences in perforin binding were not as a result of an augmented production of perforin by activated NK cells. We conclude that activation of NK cells results in an increased binding of perforin and subsequent lysis of tumour cells.

Protective effect of poly I:poly C from gentamicin nephrotoxicity in guinea pigs.

Poly(inosinic) and poly(cytidylic) acids (Poly I:Poly C) have been used to induce the production of endogenous interferon or release preformed interferon in mammals. Interferon increases the resistance of the cells. Sixty guinea pigs were used to investigate whether Poly I:Poly C gave protection from gentamicin nephrotoxicity. The animals were divided into six equal groups. Group 1 were controls; group 2 received gentamicin intramuscularly; group 3 received gentamicin and 12 h later frusemide; group 4 received gentamicin and 12 h later 1-deamino-8-D-argine vasopressin (DDAVP) intramuscularly; group 5 received subcutaneously Poly I:Poly C; group 6 received Poly I:Poly C and 24 h later gentamicin. Frusemide in group 3 potentiated gentamicin nephrotoxicity while DDAVP in group 4 ameliorated gentamicin nephrotoxicity. Poly I:Poly C itself had no toxic effect on renal tissue, while Poly I:Poly C followed 24 h later by gentamicin indicated a protective effect from the gentamicin nephrotoxicity as the functional and histological investigations indicated.

Graft-vs-leukemia activity and graft-vs-host disease induced by allogeneic Th1- and Th2-type CD4+ T cells in mice.

INTRODUCTION: The transfer of allogeneic lymphocytes contained in a hematopoietic stem cell graft confers an immune-mediated antileukemic effect, termed the graft-vs-leukemia (GVL) effect. Graft-vs-host disease (GVHD), the most detrimental complication of allogeneic BMT, largely resides within the same lymphocyte population. Therefore, separation of GVL- and GVH-reactions is a long-standing goal of experimental studies dealing with allogeneic transplantation of hematopoietic stem cells. MATERIALS AND METHODS: The objective of the current study was to assess the potential of Th1- and Th2-type CD4+ T cells in mediating GVHD and GVL effects in a fully allogeneic murine transplant model. BALB/c (H-2d) mice were given a dose of A20 (H-2d, B-cell leukemia) cells two days prior to lethal total body irradiation (TBI) and transplantation of fully mismatched (C57BL/6, H-2b) T-cell depleted (anti-Thy1.2, CD90) bone marrow (TCD-BM) cells. Graded numbers of either unmanipulated, Th1- or Th2-polarized highly enriched CD4+ donor type T cells (10(6) or 10(7)) were administered 2 h posttransplant. Infusion of 10(6) of unmanipulated, Th1-, or Th2-primed CD4+ T cells resulted in moderate GVHD-related mortality (40%, 50%, 10%) and significantly improved long-term survival (50%, 45%, 46% surviving the observation period of 120 days) as compared to animals receiving TCD-BM alone (18%). RESULTS: The administration of 10(7) unmanipulated or Th1-type CD4+ T cells given shortly after transplantation led to death of all mice within 50 days due to fatal acute GVHD. In contrast, the adoptive transfer of 10(7) Th2-primed CD4+ T cells resulted in significant improvement of long-term survival (80%) compared to the TCD-BM group. This powerful GVL effect was associated with a substantially lower incidence of lethal acute GVHD (10%) if compared to the results of transplantation of Th1-type CD4+ T cells. CONCLUSION: These results demonstrate that allogeneic Th2-type CD4+ T cells given post BMT can induce GVL effects in a cell-dose-dependent manner without increasing the risk of severe acute GVHD.

Glomerulopathy with mesangial IgM deposits: long-term follow up of 64 children.

BACKGROUND: The aim of the present study was to investigate to what extent IgM nephropathy in children with minimal change nephrotic syndrome (MCNS) and diffuse mesangial hypercellularity (DMH) evolves to focal segmental glomerulosclerosis (FSGS). METHODS: Tissues from renal biopsies were examined by light microscopy (LM), immunofluorescence (IF) and, in four cases, by electron microscopy (EM). From a total of 352 nephrotic children, 121 had renal biopsy results as steroid dependent or resistant. A diagnostic renal biopsy was also performed in 331 children with non-nephrotic proteinuria and/or hematuria. A second renal biopsy was performed in 16 children whose renal function was impaired during the follow up. The clinical course of IgM-positive children was compared with that of IgM-negative children. RESULTS: Of the 121 nephrotic children with renal biopsy, 85 were MCNS. Twenty were IF positive mainly for IgM, six of whom (30%) presented evolution to FSGS, while of the remaining 65 IF-negative children, only three (4.6%) presented evolution to FSGS. Of the total 331 children with non-nephrotic proteinuria and/or hematuria, 139 were diagnosed as IgA--IgG nephropathy, 44 had positive IF for IgM and 148 were IF negative. Of the 44 children IF positive for IgM, seven (15.9%) presented evolution to FSGS, while none of the 148 IF-negative children presented evolution to FSGS. The follow-up time for all children ranged from 1 to 14 years. CONCLUSIONS: Of IgM nephropathy patients with MCNS and DMH, a significant percentage develop impaired renal function, due to the evolution of FSGS, as revealed by repeat biopsy during long-term follow up.

Transfer of idiotypic protein primed allogeneic marrow grafts elicits potent graft-versus-myeloma effects in mice.

The active immunization of bone marrow (BM) donors with myeloma immunoglobulin (Ig) results in an idiotypic T cell response that can be transferred to the recipient. Using a murine model we evaluated the effectiveness, side-effects and underlying mechanisms of this approach. Balb/c (H-2d) mice were given a dose of HOPC-1F myeloma cells secreting the monoclonal IgG2a followed by lethal total body irradiation (7.5 Gy) 2 days later and a subsequent transplantation of 2 x 10(7) allogeneic MHC-matched DBA/2-derived marrow cells. Donors were pre-immunized with three i.p. injections of HOPC(IgG2a) or control Ig given with incomplete Freund's adjuvants (IFA) spaced 1 week apart. In some experiments, donor-spleen cells were additionally transferred 2 h post transplant. Injection of HOPC-myeloma led to death of all animals after a median survival time (MST) of 42 days. A lethal dose of TBI followed by transfer of unmanipulated marrow grafts plus splenocytes resulted in moderate antimyeloma effects with 8% of mice achieving long-term survival. Nearly the same results were obtained after transplantation of BM immunized with the control Ig. In contrast, transplantation of marrow grafts from HOPC(IgG2a) immunized donors exerted a significant GVM effect with 63% long-term survival for more than 180 days. The additional transfer of 2 x 10(7) immune splenocytes derived from the same donor resulted in even stronger anti-myeloma effects (FFR 87%). No increase in the incidence of severe acute GVHD was observed. In vitro data suggest that allogeneic CD8+ idiotype-specific T cells may be the major effector cells. Our results demonstrate that active immunization of the donor with the myeloma-specific Ig can induce powerful graft-versus-myeloma effects after allogeneic BMT.

DNA degradation in the kidney of folic acid-treated guinea pigs.

Previous investigators agree on the increased DNA synthesis and destruction of tissues caused by folic acid (FA) administered parenterally. This study aims to clarify whether DNA degradation due to the destruction of cells and nuclei precedes DNA synthesis following FA administration. Forty guinea pigs were divided into four groups: group 1, contained 10 controls; in group 2, ten animals received intraperitoneally 300 mg/kg of body wt FA; in group 3, ten animals received FA and 12 h later frusemide intramuscularly in a dose of 7 mg/kg body wt; and finally in group 4, ten animals received frusemide as in group 3. FA produced necrosis of the epithelial cells of the convoluted tubules as the detection of the beta-aminoisobutyric acid end product of DNA and thymine catabolism indicated. Frusemide administered in group 3 had a favourable effect on the acute renal failure induced by FA.

Impaired binding of perforin on the surface of tumor cells is a cause of target cell resistance against cytotoxic effector cells.

Exocytosis of perforin, subsequent binding of perforin to the target cell membrane, and formation of lytic pores form an important pathway involved in the induction of tumor cell death by cytotoxic effector cells. Here we describe a novel escape mechanism employed by tumor cells to protect themselves from granule-mediated cell death: We were able to demonstrate that the resistance of the human leukemia cell line ML-2 to natural killer (NK)-cell-mediated killing is not caused by impaired NK-cell activation but by resistance against effector molecules contained in the granules of cytotoxic cells. No resistance was observed against other pore-forming agents like complement and streptolysin O. By using the NK-susceptible leukemia cell line K562, we could show that the induction of cell death by cytotoxic granules can be blocked completely by anti-perforin antibodies, indicating that perforin is essentially involved in this process. Flow cytometric data revealed that an impaired binding of perforin on the tumor cell membrane is mainly responsible for target cell resistance, because perforin turned out to bind well on K562 cells but is not able to attach to the surface of ML-2 cells. After impaired binding of perforin was identified as a potential mechanism of tumor cell resistance, leukemia cells from 6 patients with acute myeloid leukemia (AML) were examined. As predicted, AML cells that failed to bind perforin on their surface demonstrated complete resistance toward NK-cell-mediated cytotoxicity. Thus, perforin resistance could represent an important tumor escape mechanism that should be considered when cytotoxic effector cells are used for cellular immunotherapy. (Blood. 2000;96:594-600)

Investigating the lysis of small-cell lung cancer cell lines by activated natural killer (NK) cells with a fluorometric assay for NK-cell-mediated cytotoxicity.

Activation of natural killer (NK) cells with interleukin-2 (IL-2) and IL-12 leads to an enhanced lysis of tumour cells. We investigated the ability of NK cells, with or without prior activation, to lyse a variety of small-cell lung cancer (SCLC) target cells. Specific lysis was measured with a fluorometric assay for NK-cell-mediated cytotoxicity: target cells were labelled with 3,3'-dioctadecyloxacarbocyanine, a green membrane dye. After co-incubation with NK cells, dead target cells were stained with propidium iodide, a red DNA dye that only penetrates dead cells. Of all eight SCLC cell lines tested, three were susceptible to lysis by non-activated NK cells, three were only susceptible to lysis by NK cells activated with IL-2 and IL-12 and two were not even susceptible to lysis by activated NK cells. The differences in target cell susceptibility showed no correlation with the expression of MHC-I on the surface of the target cells or with the expression of the adhesion molecules CD50, CD54, CD58 or CD102. Comparing the kinetics of the lysis of one SCLC cell line sensitive to non-activated NK cells and one sensitive only to activated NK cells, we found that maximum lysis of the former was obtained after 1 h, whereas significant lysis of the latter was only obtained after 4 h of incubation. This might be due to different mechanisms engaged in target cell lysis.

Needle-localized breast biopsy for mammographic abnormalities: a community hospital experience.

Increased awareness of benefits of early detection of breast cancer has resulted in increased numbers of screening mammographies and breast biopsies for nonpalpable lesions. Tertiary hospital studies have demonstrated positive biopsy rates from abnormal mammographic findings at 18 to 32 per cent. We examined the effectiveness of needle biopsy for nonpalpable radiographic abnormalities in our community hospital. We reviewed 167 records of patients biopsied over a 2-year period. Mammographic assessment, biopsy, and pathological assessment were performed using accepted methods. Malignancy was detected in 34 of 167 biopsies (20%). The biopsy yield rate was highest for mammographic findings of spiculated or stellate masses (75%, P < 0.01). Most biopsies (83%) were performed because of mammographic findings of microcalcifications or circumscribed enlarging masses/nodular developing densities for a positive biopsy yield rate of 16 per cent. Rates were higher in patients with personal (44%) or family history (30%) of breast cancer and in postmenopausal women (30%). These results demonstrate that 1) factors such as age, personal or family history of breast cancer, and certain mammographic features of breast lesions are associated with high biopsy yield rates, and 2) the biopsy yield rate in our community setting is comparable to tertiary hospital experience.

Eradication of residual disease by administration of leukemia-specific T cells after experimental allogeneic bone marrow transplantation.

It is now well established that allogeneic lymphocytes can mediate a potent graft-vs.-leukemia (GVL) reaction when administered to bone marrow transplant (BMT) recipients. The benefit of allogeneic lymphocyte transfusion is limited because many patients develop graft-vs.-host disease (GVHD) with prolonged pancytopenia, which sometimes proves fatal. The object of the present study was to determine the antileukemic potential and GVHD risk of in vivo-generated tumor-specific allogeneic T cells given shortly after BMT. BALB/C (H-2d) mice were inoculated with different cell doses (10(5) and 5 x 10(5)) of the A20 leukemia (BALB/C origin) 2 days prior to lethal total-body irradiation (TBI) and transplantation of allogeneic, major histocompatibility complex (MHC)-matched DBA marrow grafts (H-2d, minor difference to BALB/C). Donors of BM grafts and T cells were allogeneic, MHC-matched mice (DBA, H-2d, minor difference to BALB/C). Donor-type T cells were generated from mice immunized with irradiated A20 leukemia cells or nonmalignant BALB/C splenocytes and restimulated in vitro. Whereas no significant immunotherapeutic effect was seen in mice with high tumor burden (5 x 10(5)), allogeneic BMT in mice inoculated with 1 x 10(5) A20 cells resulted in a modest antileukemic effect. This survival rate remained unchanged when 10(6) T cells obtained from donors immunized with nonmalignant BALB/C derived cells were given posttransplantation. In contrast, a single injection of 10(6) T cells from leukemia-immunized donors led to potent GVL effects without mediating clinically overt GVHD. Our data provide evidence for the hypothesis that minimal residual disease can be eradicated without inducing GVHD by administering small amounts of specific allogeneic cytotoxic T cells after BMT.

Immunotherapeutic aspects of allogeneic peripheral progenitor cells.

In a newly developed murine model of allogeneic peripheral progenitor transplantation (PBPCT) we investigated the immunotherapeutic potential of allogeneic peripheral stem cells. The following topics were addressed by our experiments: (1) comparison of the graft-versus-leukemia effect exerted by allogeneic PBPCT compared to allogeneic BMT; (2) the influence of T-lymphocytes on GVL activity; (3) the possibility to enhance the GVL activity of allogeneic PBPCT grafts by ex vivo cytokine incubation. Balb/c mice received cells of the syngeneic B-lymphatic leukemia A20 2 days prior to TBI (7.5 Gy) and the respective graft. The recipients received allogeneic bone marrow grafts or allogeneic peripheral progenitor cells obtained after mobilization of the donors (DBA/2) with either G-CSF in a dose of 250 microg/kg/day for 5 days. In some experiments T lymphocytes were removed by immunomagnetic depletion with CD3-coated beads. An additional group received T cell-depleted and IL-2/IL12-activated PBPCT grafts. The antileukemic activity of an allogeneic PBPCT graft was significantly greater than the antileukemic activity of an allogeneic BMT graft of the same size. Relapse rates were 80% in syngeneic PBPCT, 60% after allogeneic BMT and 34% after allogeneic PBPCT. This rise in antileukemic activity is not accompanied by a rise in GVHD mortality. Depletion of T lymphocytes by CD3-coated beads resulted in a nearly complete loss of the GVL activity with a relapse rate of 75%. Incubation of the T-depleted graft with IL-2 and IL-12 to enhance NK-based GVL activity has only limited success after MHC-matched transplantation with a relapse rate of 55%. Allogeneic PBPC exert a pronounced antileukemic effect. After MHC-matched PBPCT, this GVL effect resides mostly on the T cells of the graft. Ex vivo activation of T cell-depleted grafts by IL-2 and IL-12 is accompanied by an only limited reduction of relapse rate. PBPC are a valuable modality for primary transplantation in situations with high risk of relapse and for the treatment of relapse after BMT.

Superior antileukemic activity of murine peripheral blood progenitor cell (PBPC) grafts mobilized by G-CSF and stem cell factor (SCF) as compared to G-CSF alone.

We have established a murine model to compare the antileukemic effect of PBPC grafts obtained after treatment with SCF + G-CSF and G-CSF alone. C57/BL6, DBA and Balb/c mice were splenectomized and injected with optimal doses of rhG-CSF (250 microg/kg/day s.c.) or rrSCF (100 microg/kg/day s.c.) or with a combination thereof. On day 5, we determined the hematopoietic potential (number of CD34+ cells, CFUs, total CFC, CFU-gm), the proportion of lymphoid (T, NK and B cells) and myeloid components and graft-versus-leukemia activity after allogeneic and syngeneic PBPCT and BMT in Balb/c mice bearing a B-lymphoblastic leukemia cell line (A20). The absolute number of progenitor cells increased two-fold after administering a combination of G-CSF and SCF as compared to G-CSF alone (1500 vs 940 CD34+ cells/microl; 190 vs 70 total CFC/microl; 150 vs 50 CFU-gm/microl and 6600 vs 3000 CFUs/ml). Although no differences could be detected in the cellular composition, especially in the number of T cells, PBPC grafts mobilized by the combination of G-CSF + SCF demonstrated significantly higher antileukemic activity compared to G-CSF alone (94% vs 71% freedom from leukemia, P < 0.05). Because the incidence of lethal GVHD was similar in both groups, improved GVL activity resulted in superior overall survival. Our data suggest that the higher number of progenitor cells can be harvested after G-CSF + SCF and that grafts mobilized by G-CSF + SCF exert significantly enhanced antileukemic activity compared to those harvested after treatment with G-CSF alone.

Abrogation of graft-vs.-leukemia activity after depletion of CD3+ T cells in a murine model of MHC-matched peripheral blood progenitor cell transplantation (PBPCT).

Using a murine transplantation model, we simulated a clinical situation in which major histocompatibility complex (MHC)-identical allogeneic peripheral blood progenitor cells (PBPCs) are transplanted for the treatment of a malignant disease that is resistant to resting natural killer (NK) cells but sensitive to cytokine-activated NK cells and T cell-mediated antitumor activity. We determined the influence of selective T cell depletion of allogeneic PBPC grafts on graft-vs.-leukemia (GVL) activity and investigated the effectiveness of ex vivo treatment with NK cell-activating cytokines to compensate for the putative loss of T cell-derived factors stimulating natural cytotoxicity. After pretreatment of Balb/c (H-2d) recipients with 7.5 Gy of total body irradiation, 2x10(7) rhG-CSF-mobilized PBPCs of splenectomized syngeneic or MHC-identical DBA (H-2d) mice were transferred. Selective T cell depletion (TCD) was performed by immunomagnetic purging with a mononoclonal antibody directed against CD3. In some experimental groups, T cell-depleted PBPCs were incubated with 200 U/mL interleukin (IL)-2 and 100 U/mL IL-12 for 24 hours. To investigate antileukemic activity in vivo, recipient mice were inoculated with 1x10(5) A20 cells (a B-lymphoblastic leukemia of Balb/c origin) 2 days before PBPC transplantation (PBPCT). After transplantation of unmanipulated allogeneic cells, 25% of the animals died with signs of graft-vs.-host disease (GVHD) but 71% were free from relapse 100 days after PBPCT. After TCD of allogeneic grafts with anti-CD3, the incidence of GVH-related mortality was below 5% but the leukemia-free survival rate was significantly (p < 0.05) decreased to 25% and thus was similar to that observed after syngeneic PBPCT (17%). When CD3-depleted grafts were incubated with IL-2 and IL-12, 45% of the animals remained free from leukemia; however, the difference was not statistically significant. Our results suggest that ex vivo activation of residual NK cells with IL-2 and IL-12 does not fully compensate for the abrogation of GVL activity after depletion of CD3+ T cells from MHC-matched PBPCT.

Allogeneic peripheral blood progenitor cell transplantation in a murine model: evidence for an improved graft-versus-leukemia effect.

Peripheral blood progenitor cells (PBPCs) are increasingly being used to replace bone marrow cells (BMCs) as a source of hematopoietic stem cells also in the field of allogeneic transplantation. Whereas it is well known that PBPC grafts and BM differ significantly in progenitor cell content and lymphocyte dose, the clinical consequences of these differences with respect to engraftment, graft-versus-host disease (GVHD), and the graft-versus-leukemia (GVL) effect are more difficult to assess. We present a murine model that allows us to evaluate engraftment, GVHD, and GVL effect of allogeneic PBPC transplantation (PBPCT). Balb/c mice (H-2d) served as recipients. Donors were major histocompatibility complex-matched DBA/2 mice or syngeneic Balb/c mice, respectively. Experiments with increasing numbers of BMCs or Filgastrim-mobilized PBPCs showed that the number of progenitor cells in the graft was correlated with the probability to engraft, irrespective of the graft type. With identically high cell numbers transferred (1 x 10(9) nucleated cells/kg body weight [BW]), the mortality rates due to GVHD (25%) were about the same after allogeneic BM transplantation (BMT) and allogeneic PBPCT, although PBPC grafts contained four times more CD3+ T cells as compared with BM grafts (6.2 x 10(8) v 1.4 x 10(8)/kg BW). For investigation of GVL activity, Balb/c recipients were injected with syngeneic cells of the B-lymphocytic leukemia cell line A20 2 days before transplantation. After total body irradiation to a dose of 7.5 Gy, 1 x 10(9)/kg BW Balb/c PBPCs, DBA BMCs, or DBA PBPCs were infused. The relapse rates observed were 80% after syngeneic PBPCT (n = 22), 60% after allogeneic BMT (n = 23), and 34% after allogeneic PBPCT (n = 26) (allogeneic BMT v PBPCT, P = .032). We conclude that transplantation of allogeneic PBPCs instead of BM may enhance the GVL effect without an increase of GVHD.