Outcome of treatment after first relapse in adults with acute lymphoblastic leukemia initially treated by the LALA-94 trial.

Fifty-four percent of adults with acute lymphoblastic leukemia (ALL) who entered the LALA-94 trial experienced a first relapse. We examined the outcome of these 421 adult patients. One hundred and eighty-seven patients (44%) achieved a second complete remission (CR). The median disease-free survival (DFS) was 5.2 months with a 5-year DFS at 12%. Factors predicting a better outcome after relapse were any transplant performed in second CR (P<0.0001), a first CR duration >1 year (P=0.04) and platelet level >100 x 10(9)/l at relapse (P=0.04). Risk groups defined at diagnosis and treatment received in first CR did not influence the outcome after relapse. The best results were obtained in a subset of patients who were eligible for allogeneic stem cell transplantation (SCT). Geno-identical allogeneic SCT was performed in 55 patients, and 3 patients received donor lymphocyte infusions. Forty-four transplantations were performed from an unrelated donor (of which four were cord blood). We conclude that most adult patients with recurring ALL could not be rescued using current available therapies, although allogeneic SCT remains the best therapeutic option.

Autologous stem cell transplantation in adults with acute lymphoblastic leukemia in first complete remission: analysis of the LALA-85, -87 and -94 trials.

To evaluate the results of autologous stem cell transplantation (ASCT) in a large population of adults with acute lymphoblastic leukemia (ALL) in first complete remission (CR), we performed an individual data-based overview of the last three trials from the LALA group. Overall, 349 patients with ALL prospectively randomized in the consecutive LALA-85, -87, and -94 trials to receive either ASCT or chemotherapy as post-CR treatment were analyzed. Eligibility criteria were 15-50-year-old patients without sibling donors in both LALA-85/87 trials and 15-55-year-old patients with high-risk ALL and no sibling donors in the LALA-94 trial. Intent-to-treat analysis, which compared 175 patients from the ASCT arm to 174 patients from the chemotherapy arm, showed that ASCT was associated with a lower cumulative incidence of relapse (66 vs 78% at 10 years; P=0.05), without significant gain in disease-free or overall survival. Despite a possible lack of statistical power, a nested case-control analysis performed in 85 patient pairs adjusted for time to transplant and prognostic covariates confirmed these intent-to-treat results in patients actually transplanted. Of interest, the reduced relapse risk after ASCT translated in better disease-free survival in the 300 rapid responders who reached CR after the first induction course.

Comparative outcome of reduced intensity and myeloablative conditioning regimen in HLA identical sibling allogeneic haematopoietic stem cell transplantation for patients older than 50 years of age with acute myeloblastic leukaemia: a retrospective survey from the Acute Leukemia Working Party (ALWP) of the European group for Blood and Marrow Transplantation (EBMT).

Results of reduced intensity conditioning regimen (RIC) in the HLA identical haematopoietic stem cell transplantation (HSCT) setting have not been compared to those after myeloablative (MA) regimen HSCT in patients with acute myeloblastic leukaemia (AML) over 50 years of age. With this aim, outcomes of 315 RIC were compared with 407 MA HSCT recipients. The majority of RIC was fludarabine-based regimen associated to busulphan (BU) (53%) or low-dose total body irradiation (24%). Multivariate analyses of outcomes were used adjusting for differences between both groups. The median follow-up was 13 months. Cytogenetics, FAB classification, WBC count at diagnosis and status of the disease at transplant were not statistically different between the two groups. However, RIC patients were older, transplanted more recently, and more frequently with peripheral blood allogeneic stem cells as compared to MA recipients. In multivariate analysis, acute GVHD (II-IV) and transplant-related mortality were significantly decreased (P=0.01 and P<10(-4), respectively) and relapse incidence was significantly higher (P=0.003) after RIC transplantation. Leukaemia-free survival was not statistically different between the two groups. These results may set the grounds for prospective trials comparing RIC with other strategies of treatment in elderly AML.

[Nucleic acid testing: Biomerieux Roche technology. Setting up of limits concerning temperature, volume and incubation time during the nucleic extraction step]. / Dépistage génomique viral : technique combinée biomérieux/roche. Etude des limites de tolérance des parametres températures, temps d'incubation et volumes au cours de l'extraction des acides nucléiques par le nuclisens extractor.

Nucleic acid testing is carried out in several steps: plasma pooling, nucleic acid extraction, amplification and detection. The target values of temperature, volume and incubation time are mentioned in the initial protocol without giving their limit values. The objective of this work was to determine the range of values in which the test remains positives. So we have tested: 1) the temperature and incubation time of plasma in lysis buffer (37 degrees C +/- 3 et 30 min +/- 10); 2) the influence of volume and incubation time of silica (50 mul +/- 10 et 10 min +/- 5); 3) the variation of the eluate volume after nucleic extraction. We have also studied the influence of the internal control volume variation. For each parameter the assays were performed at sensitivity limit of the technique and repeated several times. Our results showed that: 1) for all parameters evaluated the tests remain positive within a wide range of values; 2) It is not necessary to set up a sophisticated measurement process; 3) the technique is robust.

No expansion of the pre-B and B-cell compartments in the bone marrow of patients with multiple myeloma.

We have recently demonstrated that the CD24 antigen density of bone marrow (BM) lymphoid cells discriminates between pre-B cells and mature B-cells. Using this new method, we evaluated the B-cell lineage in the BM and peripheral blood (PB) of 18 patients with multiple myeloma (MM). First, the percentage of pre-B cells was significantly reduced by 40% in the BM of patients with MM: 2.3% +/- 2.2% versus 5.7% +/- 2.8% of normal BM lymphoid cells (P less than 0.01). This finding was associated with a significant reduction (50%) of the percentage of mature B-cells in both BM and PB, especially in patients with progressive disease (P less than 0.05). In contrast to what has been reported previously, we have not found any pre-B cells in the PB of these patients with MM. Secondly, BM pre-B and B-cell patients with MM did not express any activation markers (CD23, CD25, or CD71 antigens) and no CD5+ B-cells were found in the BM unlike in PB (8% CD5+ B-cells). Taken together, these data do not support the concept of a direct involvement (i.e, expansion or activation) of pre-B cells in MM without excluding the possibility of an early oncogenic event at the pre-B cell stage. Furthermore, our data emphasize this important reduction of the B-cell compartment (including that of pre-B cell) as a major cause of the humoral immunodeficiency in MM.

Follow-up of complete cytogenetic remission in patients with chronic myeloid leukemia after cessation of interferon alfa.

PURPOSE: A small proportion of patients with chronic myeloid leukemia (CML) achieve a complete cytogenetic response (CCR), defined as the disappearance of Philadelphia (Ph) chromosome-positive metaphases, after treatment with interferon alfa (IFN). In this population of patients, the question of whether treatment should then be withdrawn is not yet resolved. PATIENTS AND METHODS: In the present study, we followed 15 patients who stopped IFN after achieving CCR. In nine patients IFN was stopped in view of adverse reactions (n = 8) or patient's choice (n = 1). For the remaining six patients, the treatment was stopped because no BCR/ABL rearrangement could be detected by reverse transcriptase polymerase chain reaction (RT-PCR) in four successive analyses using peripheral-blood samples. RESULTS: Loss of CCR and survival were not statistically different (P =.48; P =.7) for the 15 patients who stopped IFN compared with 41 other CCR patients who continued IFN therapy in our institution. The median follow-up after discontinuation of IFN treatment was 36 months (range, 6 to 108 months). Seven patients (47%) (females, or CCR > 24 months and RT-PCR negative before IFN cessation; P <.0001) did not relapse. Eight other patients (53%) relapsed (lost CCR) within 3 to 33 months of treatment discontinuation. One of them relapsed in major cytogenetic remission (MCR) and was still in MCR 87 months after stopping therapy without any treatment. CONCLUSION: It is possible to stop IFN treatment at least in some patients with CML who achieve a prolonged period of CCR. This study also illustrates the hypothesis that persistence of low numbers of Ph-positive cells does not necessarily imply hematologic relapse.

Randomized trial of bone marrow versus lenograstim-primed blood cell allogeneic transplantation in patients with early-stage leukemia: a report from the Société Française de Greffe de Moelle.

PURPOSE: To compare hematologic recovery in patients receiving allogeneic blood cell transplantation (BCT) with those receiving allogeneic bone marrow transplantation (BMT). PATIENTS AND METHODS: One hundred eleven patients with leukemia in the early stages and with HLA-matched sibling donors were randomized in this study. One hundred one underwent transplantation. Standard procedures for collection and transplantation were used. Patients did not receive prophylactic granulocyte colony-stimulating factor after undergoing transplantation. In addition to clinical end points being established, a prospective and comparative economic evaluation of the first 6 months after transplantation was performed. RESULTS: Groups were balanced for patient, donor, and transplant characteristics. Blood cell collection led to the collection of a higher number of CD34(+) and CD3(+) cells than did bone marrow collection (P < 10(-6)) without reported side effects for the donor. Patients in the BCT group reached platelet counts of 25 and 50 x 10(9) platelets/L 8 and 11 days earlier than did the BMT group (P < 10(-4) and P < 10(-5)), respectively. This resulted in fewer platelet transfusions during the first 180 days after transplantation (P =.002) for the former group. The time to reach neutrophil counts of 0.5 and 1 x 10(9) neutrophils/L was 6 and 7 days shorter, respectively, in the BCT group than in the BMT group (P < 10(-5)). This quicker hematologic recovery was associated with a shorter length of hospitalization and a decrease in total cost of procedure during the first 6 months. CONCLUSION: This study establishes that allogeneic BCT results in quicker hematologic recovery but is associated with a higher occurrence of chronic graft-versus-host disease.

Autologous peripheral-blood progenitor-cell support following high-dosechemotherapy or chemoradiotherapy in patients with high-risk multiple myeloma.

PURPOSE: The aims of the current study were to evaluate in patients with high-risk multiple myeloma (MM) the feasibility and usefulness of high-dose chemotherapy or chemoradiotherapy followed by hematopoietic stem-cell support with autologous peripheral-blood progenitor cells (PBPC) harvested after high-dose cyclophosphamide (HDCYC). PATIENTS AND METHODS: Seventy-three patients with high-risk MM were entered onto the study. Before the procedure, all patients had received HDCYC to collect PBPC by leukapheresis. One patient died of infection after HDCYC. All other patients subsequently received high-dose melphalan (HDM) (140 mg/m2) either alone (n = 1) or associated with either busulfan (16 mg/kg; n = 4) or total-body irradiation (TBI) (8 to 15 Gy; n= 67). In addition, three of the latter patients received cyclophosphamide (120 mg/kg). Thereafter, PBPC were reinfused either alone in 61 patients or together with back-up bone marrow cells in 11 patients in whom the granulocyte-macrophage colony-forming unit (CFU-GM) cell content of the leukapheresis was low. RESULTS: One patient died of acute cardiac failure after reinfusion of PBPC; three patients did not respond after autologous blood progenitor cell transplantation (ABPCT), while the other 68 patients achieved either a complete response (CR; n = 32) or partial response (PR; n = 36). Thirty-six patients relapsed or progressed after a median response duration of 14.5 months (range, 3 to 43) and 19 of these subsequently died. Four other patients died while still responsive of lung cancer (n = 1) or infection (n = 3). The remaining 28 patients are currently alive and still responding with a median follow-up duration of 27 months (range, 6 to 66). The 3-year probability of survival was 66% +/- 12% (95% confidence interval [CI] after ABPCT and 77% +/- 51% (95% CI) from diagnosis. CONCLUSION: High-dose chemotherapy or chemoradiotherapy followed by autologous PBPC support in MM is feasible and efficient. Further studies are needed to confirm these encouraging, although preliminary, results and to compare this technique with other therapeutic strategies.

Allogeneic hematopoietic stem-cell transplantation after nonmyeloablative preparative regimens: impact of pretransplantation and posttransplantation factors on outcome.

PURPOSE: To analyze the impact of pre- and posttransplantation factors on the outcome of allogeneic transplantation after nonmyeloablative conditioning regimens. PATIENTS AND METHODS: Ninety-two allogeneic transplantations after nonmyeloablative preparative regimens were reported to the Société Française de Greffe de Moelle Registry registry. Initial diagnoses were lymphoid diseases (n = 22), myeloma (n = 14), acute leukemia and myelodysplasia (n = 41), chronic myelogenous leukemia (n = 12), and solid tumors (n = 3). Forty-six patients had previously received a transplant, and 49 had progressive disease before transplantation. Three types of conditioning regimens were used with fludarabine or antithymocyte globulins. Eighty-nine patients underwent transplantation, 60 from peripheral-blood progenitor cells. Eighty-six patients received graft-versus-host disease (GHVD) prophylaxis for a median duration of 53 days. RESULTS: Seventy-nine patients engrafted, with 40 complete and 21 mixed chimerisms. The acute GHVD rate at 3 months was 50% +/- 11%. Fifty-two patients achieved complete remission and 12, partial remission. At 18 months after transplantation, the overall survival (OS) and the transplant-related mortality (TRM) were 32% +/- 12% and 38% +/- 14%, respectively. Initial diagnosis and disease status before transplantation significantly influenced survival. Age and GHVD prophylaxis type significantly influenced TRM. We also showed an impact of GHVD prophylaxis duration on OS and TRM. In multivariate analysis, three factors remained of prognostic value on OS: initial diagnosis, disease status at transplantation, and GHVD prophylaxis duration. CONCLUSION: This series shows encouraging results from nonmyeloablative conditioning regimens before allotransplantation and demonstrates the impact of some pre- and posttransplantation factors on outcome after transplantation.

Cost effectiveness of day 5 G-CSF (Lenograstim) administration after PBSC transplantation: results of a SFGM-TC randomised trial.

This randomised trial was designed to compare two groups treated with different G-CSF administration schedules with a third group receiving no G-CSF, after autologous peripheral blood stem cell transplantation (APBSCT). Children and adults with haematological malignancies or solid tumours were randomly assigned to receive either 150 microg/m2/day of Lenograstim starting on day 1 (G1) or on day 5 (G5) post APBSCT, or no Lenograstim (G0). Randomisation was stratified according to the conditioning regimen (Busulfan vs TBI vs no Busulfan and no TBI) and the graft CD 34+ cell count. A total of 240 patients were randomised; 239 were evaluable. All three patient groups were comparable. Median duration of neutropenia was 9 days (4-40), and 10 days (5-15) in the G1 and G5 groups, respectively, significantly shorter than in the G0 group, 13 days (7-36) (P < 0.0001). No difference was observed in the duration of thrombocytopenia, transfusion support and extra-haematological complications. The duration of post transplant hospitalisation was significantly shorter in adults who received G-CSF. Clinical and cost arguments favour the initiation of G-CSF on day 5 in adults. The same policy could be applied in children given that clinical management is easier and costs are similar.

The impact of donor gender on outcome of allogeneic hematopoietic stem cell transplantation for multiple myeloma: reduced relapse risk in female to male transplants.

The impact of the donor gender on outcome in HLA-identical sibling donor hematopoietic stem cell transplantation for multiple myeloma was studied in a retrospective registry study of 1312 patients (476 male to male (M --> M); 334 female to male (F --> M); 258 male to female (M --> F); 244 female to female (F --> F) reported to the European Group for Blood and Marrow Transplantation (EBMT). The best overall survival (OS) from the time of transplantation was found in F --> F (median 41 months) with no significant difference between other groups (median 25 months in M --> M, 18 months in F --> M, 19 months in M --> F) despite a significantly higher nonrelapse mortality in F --> M. This was due to a significantly lower relapse rate (REL) in F --> M compared to all other groups. Before 1994, OS was poorer in F --> M than in M --> M, which improved to similarity from 1994 onwards (median 29 months in M --> M and 25 months in F --> M). The reduced REL contributed to this improvement in F --> M indicting a gender-specific graft vs myeloma effect. Therefore, a female donor is as good as a male one for male patients, while for female patients gender disparity is a negative factor for outcome.

Peripheral neuropathy after autologous blood stem cell transplantation for multiple myeloma.

We report a case of peripheral neuropathy occurring after autologous blood stem cell transplantation (ABSCT) for multiple myeloma. The patient, free of neurological symptoms, was transplanted in partial remission, and achieved a complete remission after transplantation. A severe peripheral, symmetric, distal sensori-motor polyneuropathy appeared at day 25 and worsened progressively until commencement of corticosteroid therapy. A peripheral nerve biopsy showed endoneurial cellular infiltrates which were predominantly composed of T cells identified by immunocytochemistry. Ultrastructural examination showed acute axonal damage. Electrophysiologic studies performed before and during the treatment were consistent with a severe axonal degeneration and showed a marked improvement, concomitant with the favorable clinical outcome. This is the first report of peripheral neuropathy after ABSCT.

Response to recombinant interferon alpha in patients with chronic myelogenous leukemia in a single center: results and analysis of predictive factors.

To improve the management of chronic myeloid leukemia (CML) in a single center, we used interferon alpha (IFN alpha) to treat newly diagnosed CML patients and investigated the factors predictive of a major cytogenetic response. Fifty-two patients (pts) with a median age of 51.5 years (16-68), were given interferon alpha (IFN alpha) (5 millions/m2/day, subcutaneously). The median interval between diagnosis and IFN alpha was 41.5 days (0-160). The doses of INF alpha were adjusted to maintain the white blood cell (WBC) count between 1.5 and 5 x 10(9)/l and the platelet count between 50 and 100 x 10(9)/l. At diagnosis, Sokal's criteria were used to classify patients into three groups: low (n = 24), intermediate (n = 19) and high risk (n = 9). A complete hematological response (CHR) was achieved in 42 cases (80.7%). A partial response was present in nine; only one patient did not respond. By multivariate logistic regression analysis, only the age at diagnosis was found to influence the CHR rate (P = 0.06). Cytogenetic response was evaluated in 46 responder patients. Twenty-three patients achieved a major cytogenetic response (MCR) which was either partial ( > or = 65% pH negative cells) (n = 3) or complete (CCR) (n = 20). By univariate analysis, two disease-related variables were found to influence the MCR rate in 40 evaluable CHR patients: spleen size at diagnosis and peripheral blood blast percentage. However, using either univariate or multivariate analysis, the most significant factor was the achievement of CHR within 3 months (P < 0.0004 and P < 0.0002, respectively). These results show that IFN alpha can induce high rates of hematological and cytogenetic responses when administered in doses leading to myelosuppression. The achievement of CHR within 3 months could be useful to identify early, those patients who will not respond to IFN alpha and who need alternative treatments such as allogeneic or autologous stem cell transplantation.

Autografting in chronic myeloid leukemia: an overview.

Autografting could become a promising treatment for patients with chronic myeloid leukemia (CML) who cannot undergo allogeneic bone marrow transplantation or failed to respond to recombinant alpha-interferon (IFN). In this review, we analyze the results which have been published for patients transplanted in chronic phase and which suggest that autografting could prolong survival, at least in some patients. We also discuss the different methods of purging whose clinical efficacy remains to be assessed.

Factors affecting both peripheral blood progenitor cell mobilization and hematopoietic recovery following autologous blood progenitor cell transplantation in multiple myeloma patients: a monocentric study.

The aim of the study was to analyze the factors influencing peripheral blood progenitor cell (PBPC) collection after high-dose cyclophosphamide (HDCYC) (7 g/m2) and hematopoietic recovery after autologous transplantation of HDCYC-mobilized PBPC (ABPCT) in 116 patients with aggressive multiple myeloma (MM). Following HDCYC 74 patients received hematopoietic growth factors (HGF), either G-CSF (n = 19) or GM-CSF (n = 55). All the patients were subsequently planned to undergo ABPCT. PBPC collection was possible for 106 patients. The most important prognostic factor for collection of more than 25 x 10(4) CFU-GM cells/kg and 2 x 10(6) CD34+ cells/kg was the use of HGF (P = 0.002 and 0.009, respectively). Previous use of an alkylating agent, response to treatment before HDCYC, and interval between diagnosis and HDCYC were also significant factors (P = 0.004, 0.025 and 0.001, respectively). The number of CFU-GM cells infused was the most important parameter for rapid and complete hematological recovery after ABPCT (P < 0.0001). Thus the use of HGF post-HDCYC is the major factor which, associated with reduced time between diagnosis and HDCYC and the use of an alkylating agent, could increase the numbers of hematopoietic progenitors collected, and subsequently improve hematopoietic recovery following ABPCT in MM patients.

Cytokine-mediated expansion of 5-FU-resistant peripheral blood stem cells.

We evaluated the expansion capacity of untreated and 5-fluorouracil (5-FU)-resistant peripheral blood stem cells (PBSC) after 7-day incubation with interleukin-1 (IL-1) plus IL-3 plus stem cell factor (SCF) or with medium alone. We found a significant increase in the proportion of CD34+ cells in the PBSC fraction resistant to 25 micrograms/mL 5-FU after 7-day incubation with IL-1 plus IL-3 plus SCF as compared with the untreated fraction (p = 0.011). We also showed that 5-FU-resistant PBSC have a greater capacity for expansion of IL-1/IL-3/SCF-responsive immature progenitors (p = 0.05), amplification of IL-3 plus GM-CSF responsive progenitors (p = 0.01), and production of committed single growth factor-responsive (granulocyte-macrophage colony-stimulating factor [GM-CSF]) precursors (p = 0.01) than the untreated PBSC. The expansion of all types of progenitors and CD34+ cells was only observed after 7-day incubation with IL-1 plus IL-3 plus SCF. These results suggest that PBSC contain a primitive stem cell population with an enhanced expansion capacity that is identified by 5-FU resistance. As these cells can be expanded in vitro, they may then be suitable for a number of clinical applications.

Correction of the enzyme defect in cultured congenital erythropoietic porphyria disease cells by retrovirus-mediated gene transfer.

Congenital erythropoietic porphyria (CEP) is a genetic disease characterized by an overproduction and accumulation of porphyrins in bone marrow. The enzyme defect concerns uroporphyrinogen III synthase (UROIIIS), the fourth enzyme of the heme biosynthetic pathway. It is the most severe porphyria and the treatment is largely symptomatic: gene therapy would represent a great therapeutic improvement. As a step toward the development of an effective gene therapy, we have constructed two retroviral vectors, LUSN and pMFG-US (with and without the selectable marker Neo), containing a full-length human cDNA for UROIIIS. Recombinant retroviruses were obtained by transfection of the LUSN or pMFG-US plasmid into the amphotropic packaging cell line psi CRIP. For each construct, three different producing clones were selected for their high titer (LUSN) or for their ability to express the message at a high level (pMFG-US). In vitro amplification of genomic DNA from target tissue demonstrated the presence of vector sequences. Murine fibroblasts infected in vitro expressed the human enzyme efficiently, as indicated by RNA and enzymatic studies. Retroviral-mediated gene transfer was then used to introduce the UROIIIS cDNA into human deficient cells. Enzyme activity was increased from 2% (deficient fibroblasts) to 121-274% of the normal value for the different clones. Transduced cells selected with G418 presented an 18-fold increase in enzyme activity compared to the normal cells. Furthermore, high gene transfer rate into peripheral blood progenitor cells (PBPB) was documented by in vitro amplification (PCR). These results demonstrate the potential usefulness of somatic gene therapy for the treatment of CEP.

Treatment of hematological malignancies relapsing after allogeneic bone marrow transplantation.

The rate of relapse after allogeneic bone marrow transplantation (BMT) varies between 15 and 60%. New therapeutic strategies are required urgently as no significant results have been obtained with standard chemotherapy. The best results of second allogeneic BMT have been obtained when the interval between the first and the second transplant was more than 6 to 20 months, depending on the study. Veno-occlusive disease was an important cause of non-leukemic death (13-65%). As the toxicity of second BMT is very high, other treatments have been considered: complete remissions were reported after sudden discontinuation of the immunosuppressive therapy. Interferon-alpha has been used for chronic myeloid leukemia patients and may achieve hematological and cytogenetic complete remission. More recently, donor leucocytes transfusions have been proposed and at least in some cases, have led to molecular complete remission (polymerase chain reaction with double amplification) in chronic myeloid leukemia patients. However, non predictable marrow aplasias and graft-versus-host reactions hamper the efficacy of this strategy. Finally, hemopoietic growth factors used to promote donor cell growth produce interesting results which deserve further studies.

Up-regulation of interleukin (IL)-6 receptor gene expression in vitro and in vivo in IL-6 deprived myeloma cells.

Myeloma cells absolutely require interleukin-6 (IL-6) for growing in vivo in patients with multiple myeloma and exogenous IL-6-dependent myeloma cell lines have been reproducibly obtained. In this study we show a dramatic up-regulation of the IL-6 receptor (gp80 chain) gene expression in myeloma cell lines following the removal of exogenous IL-6. Such a regulation was also known to occur in IL-6-deprived myeloma cells in vivo in three patients who were treated with optimal doses of anti-IL-6 monoclonal antibodies. The direct effect of IL-6 on IL-6 receptor gene expression in myeloma cells was further confirmed by adding IL-6 to an autonomously growing myeloma cell line.

Flow cytometric study of idarubicin and daunorubicin accumulation and the effect of verapamil in leukemic cell lines and fresh cells from patients with acute non-lymphoblastic leukemia.

By using flow cytometry, the intracellular accumulation (Acc) of idarubicin (IDA) and daunorubicin (DNR) and the effect of verapamil (VRP) on both anthracycline accumulation (VRP index) were studied in leukemic cell lines (K562 and HL60 and their two DNR-resistant subclones) and fresh leukemic cells. IDA accumulated more than DNR in both parental (K562: p < 0.03 and HL60: 0.09) and resistant cell lines (p < 0.01 for both cell lines) irrespective of whether or not they were treated with VRP. VRP index was higher for DNR than for IDA (p < 0.05). Similar results were observed in fresh leukemic blasts from 25 patients with ANLL (IDA Acc superior to DNR Acc: p < 0.0001; higher VRP index for DNR than for IDA: p < 0.01). The higher Acc of IDA than DNR seen in fresh leukemic cells could explain the better clinical efficacy of IDA reported in patients with ANLL.