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Biomedical subjects

B Löwenberg

Publications and source records attributed to B Löwenberg.

At least 19 recordsLinked to original sources
PubMed2006

[Views on the financing of biomedical scientific research; the report 'Erop of eronder' (Sink or swim) from the KNAW (Royal Netherlands Academy of Arts and Sciences)].

In a recent report, entitled 'Erop of eronder. Financiering van (bio)medisch wetenschappelijk onderzoek' [Sink or swim. The financing of (bio)medical scientific research], the Royal Netherlands Academy of Arts and Sciences has reviewed various aspects of the current financing system. The recommendations concern a funding process with emphasis on open programmes focusing on researcher-initiated research, creating an earmarked budget for matching obligations, creating technology transfer centres offering broad expertise for the validation ofthe scientific results, and giving priority to the establishment of a European Research Council that encourages excellence in fundamental research within the European research area.

Biomedical Research↗
PubMed2006

High-vs low-dose cytarabine combined with interferon alfa in patients with first chronic phase chronic myeloid leukemia. A prospective randomized phase III study.

A prospective randomized phase III study was performed to evaluate whether intensified cytarabine would induce a higher response rate and longer event-free interval as compared to low-dose cytarabine in chronic myeloid leukemia (CML). One hundred and eighteen patients with CML in early chronic phase entered the study. Twenty-eight out of 32 patients assigned to group A received two cycles of a combination of intensified cytarabine and idarubicin followed by interferon alfa (IFN-alpha) maintenance, 28 patients in group B received standard treatment by a combination of low-dose cytarabine and IFN-alpha. Forty-nine patients with a human leukocyte antigen-identical sibling donor proceeded to allogeneic stem cell transplantation (allo-SCT) and nine patients were excluded from the analysis. Hematological response was observed in 97% of the patients in group A vs 86% of the patients in group B during the first year of treatment. In group A, 16 patients (50%) achieved a major cytogenetic response, which compared to seven patients (25%) with a major cytogenetic response in group B. With a median follow-up of 58 months (range 34-76), event-free survival was not significantly different between arms A and B. The estimated 5-year survival rate was 56% in the intensified arm and 77% in the low-dose arm (P = 0.05). Recipients of allo-SCT showed a 5-year estimated survival rate of 55%. Although intensified cytarabine induced a higher initial percentage of major and complete cytogenetic responses, responses were not sustained by IFN-alpha maintenance therapy.

Adolescent↗
PubMed2006

T-lymphocyte reconstitution following rigorously T-cell-depleted versus unmodified autologous stem cell transplants.

We compared the kinetics of T-cell recovery after extensive ex vivo and in vivo T-cell depleted autologous stem cell transplantation (SCT) for multiple sclerosis (MS; n=8) with unmodified SCT for hematological malignancies (HM; n=39). Both patient group showed a very protracted recovery of 'naive' CD4(+), 45R0(-) ( approximately CD45RA(+)) T-cells. Within the 'primed' CD4(+), 45R0(+) T-cells, the 'central memory' cells expressing the CD62L and CD27 markers were the slowest to recover. The repopulating T-cells were highly activated, as shown by increased expression of HLA-DR and the apoptosis marker CD95. The capability of CD4(+) and CD8(+) T-cells to produce IFN-gamma, IL-2 and TNF-alpha had reached normal ranges from 2 months post SCT onwards. Unexpectedly, the kinetics of T-cell recovery between 3 and 12 months post transplant was similar in T-depleted and unmodified SCT. Before SCT, the HM patients showed lymphopenia of all T-cell subsets, upregulated HLA-DR and CD95 expression and increased cytokine responses. We suggest that the similar kinetics of T-cell recovery in the two patient groups may be explained by the susceptibility to apoptosis of the activated CD4(+) T-cells in the autografts of the HM patients. This susceptibility to apoptosis would interfere with a swift and sustained CD4(+) T-cell regeneration post SCT.

Adult↗
PubMed2006

Intense T cell depletion followed by autologous bone marrow transplantation for severe multiple sclerosis.

BACKGROUND: Certain stem cell transplantation procedures might slow down inflammatory pathology in multiple sclerosis (MS). AIMS: To halt disease progression in aggressive MS by a bone marrow transplantation (BMT) protocol aimed at maximum T cell suppression. METHODS: Autologous BMT was performed in 14 patients with rapid secondary progressive MS (median EDSS score at baseline, 6; median disease duration, five years). To accomplish rigorous T cell ablation, a strong conditioning protocol was chosen--cyclophosphamide, total body irradiation, and antithymocyte globulin. To minimise the possibility of reinfusing mature T cells in the graft, bone marrow, not peripheral blood, was used as the CD34+ stem cell source. RESULTS: Median follow up was 36 months (range, 7-36). Post-transplant haemopoietic recovery was successful in all patients. Early toxicity included Epstein-Barr virus related post-transplantation lymphoproliferative disorder. Longterm effects were development of antithyroid antibodies (three) and myelodysplastic syndrome (one). One patient died of progressive disease five years after transplantation. Treatment failure, defined by EDSS increase sustained for six months or more, was seen in nine patients and stabilisation or improvement in five. Other clinical parameters generally showed the same outcome. No gadolinium enhanced lesions were seen on post-treatment magnetic resonance imaging, in either cerebral or spinal cord scans. However, cerebrospinal fluid oligoclonal bands remained positive in most cases. CONCLUSIONS: This strong immunosuppressive regimen did not prevent clinical progression in patients with aggressive secondary MS. The lack of efficacy, together with some serious side effects, does not favour the use of similar rigorous T cell depleting protocols in the future.

Adult↗
PubMed2005

[The diagnosis of acute myeloid leukaemia enhanced by using DNA microarrays].

Recently, two studies have shown that the use ofgene-expression profiling using DNA microarrays or DNA chips may improve the classification of acute myeloid leukaemia (AML). In both studies, cluster analyses based on the molecular signatures defined known subgroups as well as novel subgroups of AML. Chromosomal lesions, mutations, and abnormal gene expression with prognostic value determined the clustering. In fact, gene-expression profiling recognized leukaemias with certain chromosomal aberrations that had been missed by routine cytogenetics. Thus, gene-expression profiling allows a comprehensive classification of AML that includes previously-identified genetically-defined as well as novel prognostically-relevant subgroups. One comprehensive DNA chip may in the future replace a variety of cytogenetic, immunological and molecular techniques that are currently used in combination.

Acute Disease↗
PubMed2005

Autologous hematopoietic stem cell transplantation for autoimmune diseases.

Experimental data and early phase I/II studies suggest that high-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (HSCT) can arrest progression of severe autoimmune diseases. We have evaluated the toxicity and disease response in 473 patients with severe autoimmune disease treated with autologous HSCT between 1995 and 2003, from 110 centers participating in the European Group for Blood and Marrow Transplantation (EBMT) autoimmune disease working party database. Survival, transplant-related mortality, treatment response and disease progression were assessed. In all, 420 patients (89%; 86+/-4% at 3 years, median follow-up 20 months) were alive, 53 (11%) had died from transplant-related mortality (N=31; 7+/-3% at 3 years) or disease progression (N=22; 9+/-4% at 3 years). Of 370 patients, 299 evaluable for response (81%) showed a treatment response, which was sustained in 213 (71% of responders). Response was associated with disease (P<0.001), was better in patients who received cyclophosphamide during mobilization (relative risk (RR)3.28 (1.57-6.83)) and was worse with increasing age (>40 years, RR0.29 (0.11-0.82)). Disease progression was associated with disease (P<0.001) and conditioning intensity (high intensity, RR1; intermediate intensity, RR1.81 (0.96-3.42)); low intensity, RR2.34 (1.074-5.11)). These data from the collective EBMT experience support the hypothesis that autologous HSCT can alter disease progression in severe autoimmune disease.

Autoimmune Diseases↗
PubMed2005

ID1 and ID2 are retinoic acid responsive genes and induce a G0/G1 accumulation in acute promyelocytic leukemia cells.

Acute promyelocytic leukemia (APL) is uniquely sensitive to treatment with all-trans retinoic acid (ATRA), which results in the expression of genes that induce the terminal granulocytic differentiation of the leukemic blasts. Here we report the identification of two ATRA responsive genes in APL cells, ID1 and ID2. These proteins act as antagonists of basic helix-loop-helix (bHLH) transcription factors. ATRA induced a rapid increase in ID1 and ID2, both in the APL cell line NB4 as well as in primary patient cells. In addition, a strong downregulation of E2A was observed. E2A acts as a general heterodimerization partner for many bHLH proteins that are involved in differentiation control in various tissues. The simultaneous upregulation of ID1 and ID2, and the downregulation of E2A suggest a role for bHLH proteins in the induction of differentiation of APL cells following ATRA treatment. To test the relevance of this upregulation, ID1 and ID2 were overexpressed in NB4 cells. Overexpression inhibited proliferation and induced a G0/G1 accumulation. These results indicate that ID1 and ID2 are important retinoic acid responsive genes in APL, and suggest that the inhibition of specific bHLH transcription factor complexes may play a role in the therapeutic effect of ATRA in APL.

Basic Helix-Loop-Helix Proteins↗
PubMed2005

Splenectomy for the treatment of thrombotic thrombocytopenic purpura.

Plasma exchange is the treatment of choice for patients with thrombotic thrombocytopenic purpura (TTP) and results in remission in >80% of the cases. Treatment of patients who are refractory to plasma therapy or have relapsing disease is difficult. Splenectomy has been a therapeutic option in these conditions but its value remains controversial. We report on a series of 33 patients with TTP who were splenectomised because they were plasma refractory (n = 9) or for relapsed disease (n = 24). Splenectomy generated prompt and unmaintained remissions in all except five patients, in whom remission was delayed (n = 4) or who died with progressive disease (n = 1). Four postoperative complications occurred: one pulmonary embolism and three surgical complications. Median follow-up after splenectomy was 109 months (range 28-230 months). The overall postsplenectomy relapse rate was 0.09 relapses/patient-year and the 10-year relapse-free survival (RFS) was 70% (95% CI 50-83%). In the patients with relapsing TTP, relapse rate fell from 0.74 relapses/patient-year before splenectomy to 0.10 after splenectomy (P < 0.00001). Two patients died from first postsplenectomy relapse. Although these results are based on retrospective data and that the relapse rate may spontaneously decrease with time, we conclude that splenectomy, when performed during stable disease, has an acceptable safety profile and should be considered in cases of plasma refractoriness or relapsing TTP to reach durable remissions and to reduce or prevent future relapses.

Adolescent↗
PubMed2004

[The role of cost analysis in the evaluation of the development of medical technology. The case of allogenic stem-cell transplantation].

OBJECTIVE: To estimate the real costs of allogeneic haematopoetic stem-cell transplantation and to compare these with the historically determined budgets that are made available for this purpose ([symbol: see text] 70,038 for genetically related donors and [symbol: see text] 76,826 for unrelated donors). DESIGN: Cost analysis. METHODS: In the period 1994-1999, the direct medical costs (price level of 1998) of bone-marrow transplantation from related donors (BMT), stem-cell transplantation from unrelated donors (VUD-SCT) and allogeneic peripheral-blood stem-cell transplantation (PBSCT) from related donors were determined on the basis of data on adult patients with either acute myeloid leukaemia (n = 66) or acute lymphocytic leukaemia (n = 31). First, the medical resource use by these patients was determined and multiplied by the unit costs of each of the items. Second, a structural programme for allogeneic stem-cell transplantation brings along costs that are not evident from the registration of the medical resource use (e.g., the costs of pretransplantation screening and the selection of the donor). The costs of these items were calculated by taking inventory in the hospitals and assessed by experts. RESULTS: The average costs per transplanted patient were [symbol: see text] 98,334 (BMT), [symbol: see text] 151,754 (VUD-SCT) and [symbol: see text] 98,977 (PBSCT) during the first two years after transplantation. The greater part of the costs was incurred in the transplantation phase. In VUD-SCT, one-third of the total cost was due to the costs of finding a suitable donor. CONCLUSION: The current budget for allogeneic stem-cell transplantation is insufficient to perform the transplantations adequately. Periodic evaluation of the budgets for complicated procedures based on cost analyses has added value for the evaluation of the development of these procedures in time and can thereby contribute to the quality and continuity of care.

Adolescent↗
PubMed2002

[STI571: a new dimension in the treatment of chronic myeloid leukemia].

Three patients suffering from chronic myelogenous leukaemia (CML), a 36-year-old woman in blast crisis, and a 64-year-old woman and a 60-year-old man in the chronic phase, participated in a clinical trial with STI571, a recently developed tyrosine kinase inhibitor with relative specificity for the BCR-ABL kinase. In all three patients, complete haematologic remission occurred within 2 months of the treatment being initiated. Subsequently the patient in blast crisis underwent allogeneic stem-cell transplantation. For the second patient, who had experienced many side effects with the standard treatment, STI571 led to a better quality of life. The third patient reached complete cytogenetic remission after 3 months of treatment. The development of STI571 is a major breakthrough in the treatment of CML. There are few side effects and the short-term results are excellent in specific patient categories. Further research is needed to establish the eventual role of STI571 in the treatment of CML.

Adult↗
PubMed2002

Cost analysis of CHOP (-like) chemotherapy regimens for patients with newly diagnosed aggressive non-Hodgkin's lymphoma.

Many cost analyses of stem-cell transplantations are available, which is in sharp contrast to the level of cost analyses on first-line chemotherapy for aggressive non-Hodgkin's lymphoma (NHL). Given the scarcity of cost analyses of first-line chemotherapy for NHL, it is difficult to assess the economic impact of upcoming new treatment modalities. Therefore we performed an analysis on costs of diagnosis and treatment of patients with newly diagnosed NHL who were treated with standard CHOP (-like) chemotherapy. As many NHL patients are treated in trials and the economic effects of the trial participation are unknown, our analysis included both patients treated according to trial protocols and patients treated according to standard local practice (SLP). The cost analysis was based on the total medical consumption of the patients. It was found that costs of the trial and SLP groups are within comparable ranges, although costs of diagnostic tests were somewhat higher within the trials. In elderly patients, SLP chemotherapy was discontinued more frequently in case of leucocytopenia or thrombocytopenia. This analysis provides basic information about the costs of first-line standard chemotherapy for patients with newly diagnosed aggressive NHL and the plausible ranges in which these costs may vary. Given the results, we will initiate larger studies to investigate whether trial treatments (showing more or less similar costs as SLP treatments) are more cost-effective for patients with aggressive NHL.

Acute Disease↗
PubMed2002

Cost analysis of HLA-identical sibling and voluntary unrelated allogeneic bone marrow and peripheral blood stem cell transplantation in adults with acute myelocytic leukaemia or acute lymphoblastic leukaemia.

Allogeneic stem cell transplantation (SCT) is one of the most expensive medical procedures. However, only a few studies to date have addressed the costs of HLA-identical sibling transplantation and only one study has reported costs of unrelated transplantation. No recent cost analysis with a proper follow-up period and donor identification expenses is available on related or voluntary matched unrelated donor (MUD) SCT for adult AML or ALL. Therefore, we calculated direct medical (hospital) costs based on 97 adults who underwent HLA-identical sibling bone marrow transplantation (BMT) or peripheral blood stem cell transplantation (PBSCT), and patients who received a graft from a MUD between 1994 and 1999. The average costs per transplanted patient were Euro 98,334 (BMT), Euro 151,754 (MUD), and Euro 98,977 (PBSCT), including donor identification expenses, 2 years follow-up and costs of patients who were not transplanted after they had been planned to receive an allograft. The majority of these costs was generated during the hospitalisation for graft infusion. For MUD transplants, nearly one-third of these costs was spent on the search for a suitable donor. For patients who were alive after 2 years, cumulative expenses were calculated to be Euro 103,509 (BMT), Euro 173,587 (MUD), and Euro 105,906 (PBSCT).

Adolescent↗
PubMed2001

Tetramer-based quantification of cytomegalovirus (CMV)-specific CD8+ T lymphocytes in T-cell-depleted stem cell grafts and after transplantation may identify patients at risk for progressive CMV infection.

Recovery of cytomegalovirus (CMV)-specific T-cell-mediated immunity after allogeneic hematopoietic stem cell transplantation (SCT) is critical for protection against CMV disease. The study used fluorochrome-conjugated tetrameric complexes of HLA-A2 molecules loaded with the immunodominant NLVPMVATV (NLV) peptide derived from the CMV protein pp65 to quantify A2-NLV-specific CD8+ T cells in partially T-cell-depleted grafts administered to 27 HLA-A*0201+ patients and to monitor recovery of these T cells during the first 12 months after SCT. None of the 9 CMV-seronegative patients became infected with CMV, whereas 14 of 18 CMV-seropositive patients developed CMV antigenemia after SCT. CMV-seropositive recipients of grafts from CMV-seronegative donors required more preemptive treatment with ganciclovir (GCV) than those of grafts from CMV-seropositive donors (3 [1-6] versus 1 [0-3] courses, respectively; P =.009). The number of A2-NLV-specific CD8+ T cells in the grafts correlated inversely with the number of preemptive GCV courses administered (r = -0.61; P =.01). None of the 9 CMV-seronegative patients mounted a CMV-specific immune response as measured by monitoring A2-NLV-specific CD8+ T cells after SCT. Thirteen of 14 CMV-seropositive patients without CMV disease recovered these T cells. In spite of preemptive GCV treatment, CMV disease developed in 4 patients, who all failed to recover A2-NLV-specific CD8+ T cells after SCT (P =.002). Thus, enumeration of HLA-restricted, CMV-specific CD8+ T cells in the grafts and monitoring of these T cells after SCT may constitute a rapid and sensitive tool to identify SCT recipients at risk for developing CMV disease.

Adolescent↗
PubMed2001

Internalization-defective mutants of somatostatin receptor subtype 2 exert normal signaling functions in hematopoietic cells.

The regulatory peptide somatostatin (SST) acts via a family of G-protein-coupled receptors comprising five subtypes (SSTR1-5). G-protein-coupled receptors activate multiple signaling mechanisms, which variably depend on internalization and intracellular routing of activated receptors. We have recently demonstrated that hematopoietic precursors express SSTR2 and that SST is a chemoattractant for these cells. Herein, we characterize critical regions in SSTR2 involved in endocytosis and describe how ligand-induced internalization impacts on two major signaling functions of SSTR2 in hematopoietic cells, the activation of the Erk pathway and the induction of promigratory responses.

Amino Acid Sequence↗
PubMed2001

Epstein-Barr virus (EBV) reactivation is a frequent event after allogeneic stem cell transplantation (SCT) and quantitatively predicts EBV-lymphoproliferative disease following T-cell--depleted SCT.

Reactivation of the Epstein-Barr virus (EBV) after allogeneic stem cell transplantation (allo-SCT) may evoke a protective cellular immune response or may be complicated by the development of EBV-lymphoproliferative disease (EBV-LPD). So far, very little is known about the incidence, recurrence, and sequelae of EBV reactivation following allo-SCT. EBV reactivation was retrospectively monitored in 85 EBV-seropositive recipients of a T-cell--depleted (TCD) allo-SCT and 65 EBV-seropositive recipients of an unmanipulated allo-SCT. Viral reactivation (more than 50 EBV genome equivalents [gEq]/mL) was monitored frequently by quantitative real-time plasma polymerase chain reaction until day 180 after SCT. Probabilities of developing viral reactivation were high after both unmanipulated and TCD-allogeneic SCT (31% +/- 6% versus 65% +/- 7%, respectively). A high CD34(+) cell number of the graft appeared as a novel significant predictor (P =.001) for EBV reactivation. Recurrent reactivation was observed more frequently in recipients of a TCD graft, and EBV-LPD occurred only after TCD-SCT. High-risk status, TCD, and use of antithymocyte globulin were predictive for developing EBV-LPD. Plasma EBV DNA quantitatively predicted EBV-LPD. The positive and negative predictive values of a viral load of 1000 gEq/mL were, respectively, 39% and 100% after TCD. Treatment-related mortality did not differ significantly between TCD and non-TCD transplants, but the incidence of chronic graft-versus-host disease was significantly less in TCD patients. It is concluded that EBV reactivation occurs frequently after TCD and unmanipulated allo-SCT, especially in recipients of grafts with high CD34(+) cell counts. EBV-LPD, however, occurred only after TCD, and EBV load quantitatively predicted EBV-LPD in recipients of a TCD graft. (Blood. 2001;98:972-978)

Adolescent↗
PubMed2001

Efficacy and safety of gemtuzumab ozogamicin in patients with CD33-positive acute myeloid leukemia in first relapse.

PURPOSE: Three open-label, multicenter trials were conducted to evaluate the efficacy and safety of single-agent Mylotarg (gemtuzumab ozogamicin; CMA-676; Wyeth Laboratories, Philadelphia, PA), an antibody-targeted chemotherapy agent, in patients with CD33-positive acute myeloid leukemia (AML) in untreated first relapse. PATIENTS AND METHODS: The study population comprised 142 patients with AML in first relapse with no history of an antecedent hematologic disorder and a median age of 61 years. All patients received Mylotarg as a 2-hour intravenous infusion, at a dose of 9 mg/m(2), at 2-week intervals for two doses. Patients were evaluated for remission, survival, and treatment-emergent adverse events. RESULTS: Thirty percent of patients treated with Mylotarg obtained remission as characterized by 5% or less blasts in the marrow, recovery of neutrophils to at least 1,500/microL, and RBC and platelet transfusion independence. Although patients treated with Mylotarg had relatively high incidences of myelosuppression, grade 3 or 4 hyperbilirubinemia (23%), and elevated hepatic transaminase levels (17%), the incidences of grade 3 or 4 mucositis (4%) and infections (28%) were relatively low. There was a low incidence of severe nausea and vomiting (11%) and no treatment-related cardiotoxicity, cerebellar toxicity, or alopecia. Many patients received Mylotarg on an outpatient basis (38% and 41% of patients for the first and second doses, respectively). Among the 142 patients, the median total duration of hospitalization was 24 days; 16% of patients required 7 days of hospitalization or less. CONCLUSION: Administration of the antibody-targeted chemotherapy agent Mylotarg to patients with CD33-positive AML in first relapse induces complete remissions with what appears to be a favorable safety profile.

Acute Disease↗
PubMed2001

Unrelated marrow transplantation for adult patients with poor-risk acute lymphoblastic leukemia: strong graft-versus-leukemia effect and risk factors determining outcome.

Between 1988 and 1999, 127 patients with poor-risk acute lymphoblastic leukemia (ALL) received a matched unrelated donor transplant using marrow procured by National Marrow Donor Program (NMDP) collection centers and sent out to 46 transplant centers worldwide. Poor risk was defined by the presence of the translocations t(9;22) (n = 97), or t(4;11) (n = 25), or t(1;19) (n = 5). Sixty-four patients underwent transplantation in first remission (CR1), 16 in CR2 or CR3, and 47 patients had relapsed ALL or primary induction failure (PIF). Overall survival at 2 years from transplant was 40% for patients in CR1, 17% in CR2/3, and 5% in PIF or relapse. Treatment-related mortality (TRM) and relapse mortality, estimated as competing risk factors, were 54% and 6%, respectively, in CR1, 75% and 8% in CR2/3, and 64% and 31% in PIF or relapse. Currently 23 CR1 patients are alive and free of disease with a median follow-up of 24 months (range, 3-97). Multivariable analysis showed that CR1, shorter interval from diagnosis to transplantation, DRB1 match, negative cytomegalovirus (CMV) serology (patient and donor), and presence of the Philadelphia chromosome, t(9;22), were independently associated with better disease-free survival (DFS). Transplantation in CR and presence of t(9;22) were associated with lower risk of relapse. Shorter interval from diagnosis to transplantation, DRB1-match, negative CMV, higher marrow cell dose, and Karnofsky score of 90 or higher were associated with less TRM. These results indicate that, despite a relatively high TRM, the low relapse rate resulted in a 37% +/- 13% DFS for CR1 patients, comparing favorably to results obtained with chemotherapy alone and matching results following HLA-identical sibling transplantation.

Actuarial Analysis↗