Effects of daunorubicin and doxorubicin, free and associated with DNA, on hemopoietic stem cells.

We have compared daunorubicin (DNR)-DNA with free DNR and doxorubicin (DOX)-DNA with free DOX for their effects in vivo in mice on pluripotent stem cells and granulocytic committed stem cells. Dose-survival, time-survival, and recovery curves were obtained after one i.v. injection of either drug. The dose-survival curves of colony-forming units-spleen (CFU-S) and colony-forming units-committed stem cells (CFU-C) were exponential in shape with both agents. DNR-DNA appeared more toxic to the hemopoietic precursor cells than did free DNR. In contrast, DOX-DNA was less toxic toward CFU-S and as toxic as DOX toward CFU-C. Time-survival curves indicated a minimum level of CFU-S and CFU-C at about 33 hr. After that, the recovery of CFU-S was rapid for DNR-treated mice but remained below 50% of the controls on Day 12 for the DNR-DNA-treated group. In mice previously given injections of DOX or DOX-DNA, the recovery of the CFU-S was more protracted in time with a better recovery in mice treated with DOX-DNA. Both DNR and DNR-DNA induced an initial CFU-C decrease followed by a rapid but transient rise with a maximum on Day 4 after chemotherapy. On Day 12, the CFU-C recovery was still incomplete in both DNR- and DNR-DNA-treated mice. In the groups treated with DOX, the CFU-C recovery was more important after DOX-DNA complex than after free DOX. The results are discussed in view of the "lysosomotropic chemotherapy" hypothesis.

Transcription of genes encoding granulocyte-macrophage colony-stimulating factor, interleukin 3, and interleukin 6 receptors and lack of proliferative response to exogenous cytokines in nonhematopoietic human malignant cell lines.

Studies in recent years have suggested that human tumor cell lines are capable of responding in vitro to hematopoietic growth factors. In the present study, we investigate the transcription of the alpha and beta subunits of granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor, the alpha and beta subunits of interleukin 3 (IL-3) receptor, and the single subunit of interleukin 6 (IL-6) receptor and its associated gp130 transduction protein by PCR amplification of reverse-transcribed cellular mRNA in 34 malignant cell lines derived from a variety of histological cell types. mRNA for only a single subunit polypeptide was found in a significant minority of cell lines (23%), while in 20% both the alpha and beta subunits of either the GM-CSF receptor or the IL-3 receptor were detected among a number of different histological cell types. Transcription of the gene encoding the IL-6 receptor was found in 38% of cell lines, and all lines transcribed the gp130 transduction protein, consistent with previous observations on the ubiquity of that polypeptide. In order to test the in vitro effect of exogenously added growth factors on those malignant cell lines transcribing complete cytokine receptor, either GM-CSF, IL-3, or IL-6 was added in therapeutic concentrations (20-500 ng/ml) and cellular proliferation was measured by incorporation of [3H]thymidine. No stimulation was seen at either 3 and 6 days of culture. Production of cytokine by these cell lines was investigated at the level of transcription and by assay of peptide product. None transcribed mRNA for either GM-CSF or IL-3, while 5 of 6 (STD, DOZ, ADE, Hep-2, and Detroit) expressed IL-6 mRNA. Of these latter, 2 cell lines (ADE and Hep-2) produced IL-6 as determined by bioassay, while none produced GM-CSF or IL-3 by enzyme-linked immunosorbent assay. This suggests that in the case of GM-CSF and IL-3, failure to proliferate on addition of cytokine is not due to the prior presence of endogenous production. In contrast, at least a subset of malignant cell lines may involve a closed IL-6 autocrine loop saturating cell surface sites. These findings suggest that the ability to transcribe the genes encoding cytokine receptor is by itself insufficient to render cells cytokine responsive and that malignant cells may lack the cellular machinery for cytokine-induced proliferation. This in turn suggests that therapeutic administration of either GM-CSF, IL-3, or IL-6 may involve no additional risk of tumor regrowth in vivo.

Defective cytokine production following autologous stem cell transplantation for solid tumors and hematologic malignancies regardless of bone marrow or peripheral origin and lack of evidence for a role for interleukin-10 in delayed immune reconstitution.

A substantial body of evidence accumulated in recent years indicates a protracted delay in immune reconstitution following autologous stem cell transplantation. In order to investigate the cellular basis of this phenomenon, peripheral blood mononuclear cells were studied from recipients of autologous stem cell transplantation for solid tumors and hematological malignancies. On stimulation with phytohemagglutinin and phorbol 12-myristate 13-acetate, transplant-derived peripheral blood mononuclear cells demonstrate statistically significant depressed production of interleukin 3 (IL-3), IL-4, granulocyte-macrophage-colony-stimulating factor, and gamma-interferon as compared to normal controls, during the first 6 months following engraftment, which recover to normal levels 6 months or more posttransplant. When the overall group of transplant recipients is compared to the control group, there is a statistically significant lower production of IL-2. In addition, no differences were observed regardless of the source of the engrafted stem cells, whether from bone marrow alone (autologous bone marrow transplantation), from peripheral blood stem cells alone, or from a combination of autologous bone marrow transplantation and peripheral blood stem cells. The defect persisted past 6 months postengraftment. Transplant-derived peripheral blood mononuclear cells were stimulated with combinations of either phytohemagglutinin plus the calcium ionophore A23187, thereby circumventing the requirement for accessory cell function, or with phorbol 12-myristate 13-acetate plus anti-CD28 monoclonal antibody, mimicking the CD28-B7 cell surface-ligand interaction capable of triggering and stabilizing IL-2 gene transcription. In both situations, decreased production of IL-2 as compared to controls was observed in individuals within 6 months of transplantation. Quantitative polymerase chain reaction indicates that decreased transcription of IL-2 mRNA following transplantation is not due solely to a decrease in the absolute numbers of CD4+ T-cells but is secondary to reduced numbers of transcript copies per cell. Production of IL-10 was found to be decreased regardless of whether the autologous graft was of bone marrow or peripheral blood origin. These findings are consistent with the conclusion that: (a) multiple dysregulations exist in the production of cytokines important in immune homeostasis; (b) a defect occurs at or prior to the level of transcription of IL-2 mRNA; (c) IL-10 does not play a direct role in the pathogenesis of posttransplantation immunosuppression; and (d) there is no evidence that peripheral blood stem cells may be superior to bone marrow-derived stem cells in accelerating immune reconstitution.

Immunological and pharmacological removal of small cell lung cancer cells from bone marrow autografts.

Autologous bone marrow transplantation is used in small cell lung cancer (SCLC) to reverse the hematological toxicity induced by high dose therapy even though the presence of cancerous cells in the graft is potentially dangerous by reinfusion of the disease along with the hematopoietic stem cells. The present studies were undertaken to examine the effectiveness of anti-SCLC rat monoclonal antibodies LCA1 and LC66 plus human complement combined with a derivative of cyclophosphamide (Asta-Z 7557) for the elimination of cancerous clonogenic cells from the graft. In a series of assays conducted with three SCLC cell lines, used alone or mixed with normal bone marrow cells, the addition of Asta-Z 7557 to two cycles of treatment with monoclonal antibodies plus complement results in a 4- to 5-logarithmic reduction of the clonogenic SCLC cells detectable by limiting dilution analysis. This was superior to either treatment used alone. When normal bone marrow was submitted to the same treatment, a median (range) of 44% (15-77%) of the colony-forming unit, granulocyte-macrophage was recovered. These results suggest that the association of immunological (LCA1 and LC66 plus human complement) and pharmacological (Asta-Z 7557) removal methods is effective for purging metastatic clonogenic cells from bone marrow of SCLC patients and could be considered before autologous bone marrow transplantation.

Late intensification chemotherapy with autologous bone marrow transplantation in selected small-cell carcinoma of the lung: a randomized study.

A multicentric randomized prospective trial was conducted to test whether late intensification chemotherapy would increase the remission rate, the relapse-free survival, and the survival of small-cell lung cancer patients responding to induction chemotherapy. Autologous bone marrow transplantation was used as support to reduce the duration of the aplasia induced by very high-dose chemotherapy. As induction chemotherapy, 101 patients received, during a period of 5 months, a total dosage of 120 mg/m2 methotrexate, 4.5 mg/m2 vincristine, 1,800 mg/m2 cyclophosphamide, 180 mg/m2 doxorubicin, 160 mg/m2 cisplatin, 750 mg/m2 VP-16-213, and 30 Gy prophylactic cranial irradiation. Forty-five patients, selected for their sensitivity to this induction treatment, were randomized to a last cycle of chemotherapy that combined cyclophosphamide, BCNU, and VP-16-213 either at a conventional dosage of 750 mg/m2 intravenously (IV), 60 mg/m2 IV, and 600 mg/m2 orally or alternatively at a very high dosage of 6 g/m2 IV, 300 mg/m2 IV, and 500 mg/m2 IV, respectively. In the late intensification group, the complete remission rate increased from 39% before randomization to 79% after high-dose chemotherapy. Median relapse-free survivals after randomization for intensified and control chemotherapy groups were 28 and 10 weeks, respectively (P = .002). Median overall survival after induction therapy was 68 weeks for the intensified group compared with 55 weeks for the conventional therapy group (P = .13). Four patients died during intensification. Patients in both groups relapsed at the primary site. It can thus be concluded that late intensification chemotherapy for sensitive small-cell lung cancer increases the complete remission rate and resulted in a statistically significant increase in the relapse-free survival. However, since relapse occurred at the primary site and toxicity was high, overall survival was not significantly improved.

Restriction fragment length polymorphisms and single germline coding region sequence in VH18/2, a duplicated gene encoding autoantibody.

In this study, we analyze the restriction fragment length polymorphisms of VH18/2, a gene encoding the heavy chain of an anti-DNA antibody, and correlate that with the germline sequence of the gene's coding region. Oligonucleotides probes complementary to the CDR1 and to both the 5' and 3' halves of the CDR2 gene segments were hybridized under stringent conditions to genomic DNA digested with XbaI, and yielded polymorphic bands of 26, 24 and 18 kb with all three probes. Individuals had either one, two, or three bands in common in their genomic DNA, indicating duplication of VH18/2 genes at two sites within the IgH locus. While it is difficult to say which of the three polymorphic gene segments constitute an allelic pair, the 26 and 24 kb fragments were the most commonly seen (97% of individuals had one or both). VH18/2 is known to be over-represented in the expressed repertoire with very little nucleotide divergence from the germline sequence. In order to determine whether the observed RFLPs are due to sequence polymorphism of the VH18/2 coding region, and whether differences in the expressed genes arise from somatic mutation, size-selected genomic DNA containing the gene was cloned and sequenced. A single coding region sequence was found in the germline. The results of this study suggest that overexpression of VH18/2 may in part be due to its duplication. Like other genes encoding autoantibody, which are well conserved, nonpolymorphic and expressed early in programmed immunologic development, VH18/2 may be instrumental in the establishment or regulation of the immune repertoire.

Murine yolk sac hematopoiesis studied with the diffusion chamber technique.

The proliferation and differentiation of visceral and of parietal yolk sac cells from 9-day-old mouse embryos were studied in diffusion chambers (DC). After culture, the visceral yolk sac yielded predominantly macrophages whereas the parietal yolk sac displayed mainly plasmocyte-like cells. It is shown the latter do not synthesize immunoglobulin but rather elaborate Reichert's membrane. Neither visceral nor parietal yolk sac contained detectable pluripotent stem cells (CFUs) prior to or after DC culture, a finding which is discussed in the light of the current literature.

Cholinergic enhancement of megakaryocytopoiesis and granulocytopoiesis in culture: mediation via T-lymphocytes.

Addition of carbamylcholine, a cholinergic analogue, to bone marrow cultures enhanced megakaryocytic and granulocytic growth by 60% and 42%, respectively. When carbamylcholine was added to spleen cells cultured in the presence of pokeweed mitogen, the resulting conditioned medium (PWM-SCM) increased the number of megakaryocytic and granulocytic colonies to 159% +/- 6% and 146% +/- 10%, respectively, compared to control cultures stimulated by PWM-SCM alone. To determine if this cholinergic augmentation of colony formation was direct or mediated via accessory marrow cells, cyclosporin A (CyA), a potent T-lymphocyte function inhibitor known to suppress the production of colony-stimulating activity (CSA) by spleen cell cultures, was added to marrow cultures. CyA (3 micrograms/ml) abrogated the enhancement of megakaryocytic and granulocyte-macrophage colony growth but had no effect on colony formation when added alone. To confirm the role of T-lymphocytes in the augmented proliferation of megakaryocytopoiesis and granulocytopoiesis, bone marrow cells from T-lymphocyte-deficient nude mice were cultured in the presence of carbamylcholine. No significant change was observed in the number of megakaryocyte colony-forming units (CFU-M) and committed granulocyte-macrophage colony-forming units (CFU-C) derived from the marrow of nude mice when cultured in the presence of carbamylcholine. The data suggest that carbamylcholine-induced enhancement of megakaryocytopoiesis and granulocytopoiesis in culture is indirect, requiring a T-lymphocyte population.

Recombinant human interleukin-2 restores in vitro T-cell colony formation by peripheral blood mononuclear cells after autologous bone marrow transplantation.

Immune reconstitution after autologous bone marrow transplantation (ABMT) was studied in peripheral blood by phytohemagglutinin stimulated T-cell colony formation (CFU-TL) and by surface phenotype analysis of T-lymphocytes with monoclonal antibodies. Twenty-six patients (15 small-cell lung cancer, 5 lymphoma, 3 acute myeloid leukemia [AML], 2 germ cell cancer, and 1 melanoma) were conditioned with high-dose multiple drug combinations (plus total body irradiation in AML patients). No maintenance chemotherapy was given following treatment. Despite a rapid return to normal values of peripheral T3+, T11+ lymphocytes, the T4/T8 ratio remained below 1.0 up to 24 months after transplant, regardless of infection by cytomegalovirus (CMV). A high percentage (26% +/- 3%) of lymphocyte cells with immature phenotype (T8+, Ia+) was found during the first 6 months after transplant. Out of 84 cultures, performed in 26 patients, no growth was observed in 47 instances (22 patients) up to 28 months after grafting. Growth occurred in 37 cultures (11 patients, from 1 to 51 months after transplant) although it never reached the colony numbers of normal controls. Recombinant human interleukin-2 (rIL-2) added to lymphocyte culture induced proliferation in 8 (4 CMV-positive and 4 CMV-negative patients) out of 12 instances of no growth. In cases of depressed CFU-TL (20 cultures), rIL-2 induced a 48% and 92% increase in six CMV-positive patients and nine CMV-negative patients, respectively. These observations show that after ABMT and regardless of CMV status, defects in CFU-TL can be partially corrected by rIL-2.

Effects of escalating doses of recombinant human interleukin-2 in correcting functional T-cell defects following autologous bone marrow transplantation for lymphomas and solid tumors.

High-dose chemotherapy followed by autologous bone marrow transplantation (ABMT) in the treatment of malignancies is often associated with immune deficiency following transplantation, possibly contributing to tumor relapse or fatal infection. Interleukin 2 (IL-2), which enhances major histocompatibility complex (MHC)-unrestricted cytotoxicity in vitro, can be applied in vivo as immunotherapy to reduce these potential complications. Recombinant human IL-2 (rIL-2) was administered by continuous i.v. infusion for four courses in 19 patients following ABMT for lymphomas and solid tumors. The patients were assigned to five groups of escalating doses of rIL-2 ranging from 3 to 30 x 10(6) IU/m2/day. The immunological effects and toxicity were monitored. After a transient reduction of lymphocytes in the peripheral blood, a significant lymphocytosis was observed during the rIL-2 infusion with an augmentation of CD2+, CD25+, and CD8(+)-Ia+ T cells and a dose-related increase of CD56+ lymphocytes. Natural killer (NK) activity appeared enhanced in patients treated with as little as 6 x 10(6) IU/m2/day. No statistically significant increase in lymphokine-activated killer (LAK) activity was seen after rIL-2, when compared to LAK activity following ABMT prior to rIL-2 administration. Administration of exogenous rIL-2 to patients who have undergone ablative chemotherapy and ABMT has a role in restoring defective T-cell function. Further trials defining those patients most likely to benefit from rIL-2 integrated with ablative chemotherapy and ABMT are now warranted.

Retrovirus-mediated gene transfer of the human multidrug resistance-associated protein into hematopoietic cells protects mice from chemotherapy-induced leukopenia.

Utilization of chemotherapy for the treatment of tumors is mainly limited by its hematological toxicity. Because of the low-level expression of drug resistance genes, transduction of hematopoietic progenitors with multidrug resistance 1 (MDR1) or multidrug resistance-associated protein (MRP) genes should provide protection from chemotherapeutic agent toxicity. Successful transfer of drug resistance genes into hematopoietic cells may allow the administration of higher doses of chemotherapy and, thus, increase regression of chemosensitive tumors. The interest in the use of MRP as an alternative to MDR1 for bone marrow protection lies in its different modulation. This would allow, in the same patient, the use of MDR1 reversal agents to decrease MDR1 tumor resistance without reversing bone marrow (BM) protection of the MRP-transduced hematopoietic cells, since MRP expression is not reversed by these agents. We have constructed MRP-containing retroviral vectors using the phosphoglycerate kinase promoter and generated ecotropic producer cells. Lethally irradiated mice were engrafted with BM cells transduced by coculture with MRP producer cells. Evidence of long-term (9 months) gene transfer was provided by PCR of peripheral blood from MRP-transduced mice. Southern blot analysis confirmed the integrity of the provirus in the MRP-transduced mice. Long-term MRP expression (>5 months) was detected by RT-PCR and fluorescence-activated cell sorting of blood from living mice. High-level expression of MRP in murine hematopoietic cells reduces doxorubicin-induced leukopenia and mortality. Furthermore, we show in vivo selection of MRP-transduced cells following doxorubicin administration, with better and more significant chemoprotection after the second chemotherapy cycle. These data indicate that MRP retroviral gene transfer may be useful for chemoprotection and selection.

Immune reconstitution after bone-marrow transplantation.

Recipients of both allogeneic and autologous BMT demonstrate clinically significant immune deficiency involving T and B lymphocytes. While quantitative aspects of the immune system generally return to normal in the first 3 to 4 months, there is a prolonged delay in the recovery of qualitative immune functions. T-cell proliferation is impaired immediately after transplantation and recovers after more than 1 year. There is a documented defect in IL-2 producing cells post-BMT, but PHA-stimulated T cells are TAC+. Therefore, addition of IL-2 in vitro may normalize the T-cell proliferation defect. NK and LAK activities normalize very early post-BMT. In the light of these data, the clinical assessment of rIL-2 administration on the immunological reconstitution of ABMT patients and as consolidative immunotherapy is being investigated.

Retroviral-mediated transfer of genes encoding interleukin-2 and interleukin-12 into fibroblasts increases host antitumor responsiveness.

The transfer of genes encoding cytokines into tumor cells has emerged as a new strategy to increase in vivo host reactivity to a variety of tumors. Because gene transfer into tumor cells cannot be easily applied in the clinical setting, we have developed an experimental model of gene transfer into fibroblasts and examined the capacity of these engineered cells to elicit an antitumor immune response. Interleukin-12 (IL-12) is a heterodimeric cytokine with pleiotropic activities presenting strong antitumor and antimetastatic effects in murine models. A bicistronic retroviral vector was constructed that contained the cDNAs encoding both chains (p40 and p35) of murine IL-12 separated by an internal ribosomal entry site sequence. Syngeneic cutaneous fibroblasts obtained from newborn mice and transduced to secrete either IL-12 or IL-2 were injected subcutaneously with B16F0 or B16F1 melanoma cells. The time of tumor occurrence and overall survival of mice were significantly prolonged when B16F1 cells were coinjected with cytokine-producing fibroblasts compared with B16F1 alone or B16F1 together with unmanipulated fibroblasts. Systemic effects were seen in the mice injected with either IL-2- or IL-12-secreting fibroblasts, with the highest proliferation capability and interferon-gamma production observed in vitro from splenocytes from recipients of IL-2-secreting fibroblasts. Injection of IL-2-secreting fibroblasts or coinjection of IL-2- and IL-12-producing fibroblasts resulted in a significant increase of survival in the B16F0 model; in some cases, complete disease eradication was observed. These results suggest that cutaneous fibroblasts represent a target of choice for gene transfer and would be useful in the treatment of minimal residual disease in humans.

Chemoprotection and selection by chemotherapy of multidrug resistance-associated protein-1 (MRP1) transduced cells.

Utilization of chemotherapy for treatment of tumors is mainly limited by its hematological toxicity. Because of the low level expression of drug resistance genes, transduction of hematopoietic progenitors with multidrug resistance 1 (MDR1) or multidrug resistance-associated protein 1 (MRP1) genes should provide protection from chemotherapy toxicity. Successful transfer of drug resistance genes into hematopoietic cells might allow the administration of higher doses of chemotherapy and, therefore, increase regression of chemosensitive tumors. In addition, this approach can be used to select in vivo transduced cells by their enrichment after administration of cytotoxic drugs. Our group has studied the potential value of MRP1 to protect hematopoietic cells. The interest in the use of MRP1 as an alternative to MDR1 gene transfer for bone marrow protection lies in its different modulation. Indeed, classical P-gp reversal agents, tested in clinic to decrease MDR1 tumor resistance, have little or no effect on MRP1 function. This would allow, in the same patient, the use of reversal agents to decrease P-gp tumor resistance without reversing bone marrow protection of the transduced hematopoietic cells provided by MRP1. We constructed two different MRP1-containing vectors with either the Harvey retroviral long terminal repeat (LTR) or phosphoglycerate kinase (PGK) as promoters and generated ecotropic producer cells. MRP1 transduced fibroblasts were more resistant to doxorubicin, vincristine, and etoposide and their chemoprotection was increased after selection with chemotherapeutic agents in the presence of glutathione, a co-factor for MRP1 function. Lethally irradiated mice were engrafted with bone marrow (BM) cells transduced with MRP1 vectors (PGK promoter). We demonstrated that high expression of MRP1 in murine hematopoietic cells reduces doxorubicin-induced leukopenia and mortality. In addition, in vivo selection of MRP1-transduced BM cells was achieved following doxorubicin administration and allowed a better chemoprotection after the second chemotherapy cycle.

Recombinant interleukin-2 in metastatic renal cell carcinoma--a European multicentre phase II study.

This multinational, multicentre study represents the introduction of recombinant interleukin-2 (rIL-2) in Europe. From December 1987 to June 1989, 57 eligible patients with metastatic renal cell cancer were treated with rIL-2 administered as continuous intravenous infusion. 8 out of 51 evaluable patients responded (16%), 2 complete remission (CR) and 6 partial remission (PR). 10 patients had no change (20%). The response duration for CR was 209 and 394+ days. The median response duration for PR was 371 (range 140-506+) days. Dose-limiting grade 3-4 toxicities were hypotension in 52% of the patients, arrhythmia (4%), dyspnoea (8%), creatinine rise (4%), peripheral neurotoxicity (10%) and central neurotoxicity (10%). Toxicities most often recovered solely on interrupted therapy. 2 patients died due to catheter-related septicaemia and one patient died of rIL-2 induced renal failure. The study confirmed the antitumour efficacy of rIL-2 in renal cell cancer. Toxicities were numerous, but manageable by close observation in a normal oncology ward without routine use of an intensive care unit.

Clinical activity and benefit of irinotecan (CPT-11) in patients with colorectal cancer truly resistant to 5-fluorouracil (5-FU).

The aim of this prospective study was to assess the efficacy, clinical benefit and safety of CPT-11 (irinotecan) in patients with stringently-defined 5-fluorouracil-resistant metastatic colorectal cancer (CRC). 107 patients with documented progression of metastatic CRC during 5-FU were treated with CPT-11 350 mg/m2 once every 3 weeks in a multicentre phase II study. Tumour response and toxicity were assessed using WHO criteria. Changes in performance status (PS), weight and pain were also measured. The WHO response rate was 13/95 (13.7%, 95% CI 7.5% to 22.3%) eligible patients with a median duration of response of 8.5 months (37 weeks, range: 18-53+). There was also a high rate of disease stabilisation (44.2%) with a median duration of 4.8 months. The probability of being free of progression at 4 months was 50%. Median survival from first administration of CPT-11 was 10.4 months or 45 weeks (range: 3-66+ weeks). There was weight stabilisation or gain in 81% (73/90) of patients, a favourable outcome in PS in 91% (82/90) (improvement of WHO PS 2 or stabilisation of PS 0-1), and pain relief in 54% (26/48). There were no toxic deaths. Neutropenia was short-lasting and non-cumulative. Diarrhoea grade > or = 3 occurred in 7% of cycles and 28/107 (26%) of patients. CPT-11 350 mg/m2 once every 3 weeks has an encouraging degree of activity in progressive metastatic CRC truly resistant to 5-FU with a relatively high rate of tumour growth control translated into clinical benefit. The toxicity profile of CPT-11 is becoming better understood and has been considerably improved.

Unreliability of carcinoembryonic antigen (CEA) reverse transcriptase-polymerase chain reaction (RT-PCR) in detecting contaminating breast cancer cells in peripheral blood stem cells due to induction of CEA by growth factors.

RT-PCR is increasingly used for the detection of minimal residual disease in solid tumors. Carcinoembryonic antigen (CEA) RT-PCR seemed to be highly specific for detection of tumor cells when tested on PBMC. A very high frequency of RT-PCR amplification product for CEA in PBSC from breast cancer patients mobilized with G-CSF was found. However, this result contrasted with tumor cell detection by immunocytochemistry (ICC) which showed no correlation with RT-PCR results. In addition, CEA mRNA was amplified in most G-CSF-mobilized PBSC samples derived from patients with hematological malignancies and from healthy donors of allogeneic stem cells, although no circulating epithelial cells could be demonstrated by ICC. CEA RT-PCR expression was observed in PBMC from healthy individuals incubated in vitro with G-CSF. These data suggest that CEA transcription can be induced by G-CSF, resulting in a loss of specificity of CEA RT-PCR for tumor cell detection in PBMC. We conclude, CEA RT-PCR may not be recommended to detect tumor cell contamination in peripheral blood from patients treated with G-CSF. This may have implications on tumor cell detection by RT-PCR in tissues where endogenous or exogenous growth factors may induce the transcription of CEA or other genes.

Peripheral blood mononuclear cells from autologous hematopoietic stem cell transplantation recipients produce and respond to IL-12.

Autologous hematopoietic stem cell transplantation effectively results in restoration of hematopoiesis, but induces an often prolonged period of T cell dysfunction including redistribution of T cell subsets and defective T cell proliferation. Because IL-2 production is markedly decreased following autologous stem cell engraftment, and because IL-12 has direct stimulatory effects on TH1 cells, a major source of IL-2, we investigated the production and responsiveness of IL-12 of peripheral blood mononuclear cells (PBMC) of autologous stem cell recipients in the first 6 months following engraftment. When stimulated with S. aureus Cowan I (SAC), PBMC from autologous hematopoietic transplant recipients in the early months following engraftment show no decrease in production of IL-12 as compared to control PBMC. Furthermore, transplant-derived PBMC appear to be functionally responsive to exogenously provided IL-12 as indicated by several criteria. In vitro proliferation of total PBMC and of isolated CD4+ T cells from transplanted recipients to PHA (1 microgram/ml) + IL-12 (20 U/ml) was comparable to controls, excluding the possibility that only NK or CD8+ cells respond to IL-12. Culture of both control and transplant-derived PBMC in PHA + IL-12 (20 U/ml) or IL-2 (100 U/ml) + IL-12 (20 U/ml) combinations yielded comparable production of IFN-gamma, one of the major biological effects of IL-12 in vivo, as well as equal production of TNF-alpha, a costimulatory factor of IL-12-mediated induction of IFN-gamma by NK cells. Taken together, this in vitro evidence suggests that following autologous transplantation, PBMC do not appear to have either decreased production of endogenous IL-12 or defective functional responsiveness to exogenously provided IL-12.

Tolerance of sequential or simultaneous administration of IL-3 and G-CSF in improving peripheral blood stem cells harvesting following multi-agent chemotherapy: a pilot study.

A pilot study was devised to assess tolerance of combined administration of interleukin-3 (IL-3) and granulocyte-colony stimulating factor (G-CSF) given after chemotherapy to mobilize peripheral blood progenitors cells (PBPC). Eight patients with advanced malignancies received 1 week courses of both IL-3 and G-CSF in one of three schedules: simultaneous 7 days administration (3 patients), sequential administration (3 patients) or partial (3 days) overlap of the two growth factors (2 patients). IL-3 (7.5 micrograms/kg/day) and G-CSF (5 micrograms/kg/day for the simultaneous schedule and 12 micrograms/kg/day for the partial overlapping and sequential schedules) were administered subcutaneously. Side-effects during cytokine administration included WHO grade I-II fever in 6 of 8 patients, flu-like symptoms (including myalgias and arthralgias) in 4 of 8, WHO grade I-II headache in 2 of 8 and WHO grade II nausea and vomiting in 1 of 8. Overall, side-effects appeared similar during combined administration of IL-3 and G-CSF to those observed during administration of IL-3 alone. No fever was observed when G-CSF was administered alone. Two leukaphereses were performed following the treatment with cytokines. Only the seven patients who received cytokines following chemotherapy were analyzed for PBPC mobilization. The median collection of CFU-GM/kg per patient in the seven analyzed patients was 1.3 x 10(5) (range 5.7 x 10(2)-3.6 x 10(5)). In two patients, a second cycle of mobilization with either granulocyte macrophage-colony stimulating factor (GM-CSF) or G-CSF was administered to allow safe engraftment.(ABSTRACT TRUNCATED AT 250 WORDS)

Concentration of bone marrow progenitor cells by separation on a Percoll gradient using the Haemonetics model 30.

To perform an optimal ex vivo bone marrow purge, it is necessary to concentrate the bone marrow progenitor cells and to eliminate both the red blood cells and the polymorphonuclear leucocytes. To achieve this goal which cannot be accomplished by using the Haemonetics model 30 alone, we used the Haemonetics model 30 and a density gradient together in a two-step procedure. In the first step we obtained the buffy coat from original bone marrow grafts and in the second we reintroduced these buffy coats into the Haemonetics bowl followed by Percoll, adjusted to 1.079 g/ml, at 5 ml/min in order to recover the light density mononuclear cells. After this second step, the mean volume of the marrow and the RBC and nucleated cell contaminations were reduced to 9%, 0.96% and 16% of their original values the unseparated bone marrow, respectively. This was far better than the values obtained after the first step (volume: 19%; RBC: 10%; nucleated cells: 54%). The CFU-GM recoveries after the first and second steps were 71% and 70% of the original samples, respectively. The entire procedure lasted between 75 and 150 min. At this time, 17 of the 24 patients whose bone marrow was separated using Percoll gradient in the Haemonetics bowl have been grafted. Thirteen of these 17 patients had an evaluable haematological recovery which was complete and rapid for all but one patient with acute myeloid leukaemia. These results demonstrate that the introduction of a density gradient into the Haemonetics model 30 bowl is possible and effective. The reduction in total volume and cell number permits ex vivo purging, without decreasing the grafting capability.