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H J Kolb

Publications and source records attributed to H J Kolb.

At least 55 records · Page 3Linked to original sources
PubMed2000

Prognostic significance of increased IL-10 production in patients prior to allogeneic bone marrow transplantation.

IL-10 is a potent immunosuppressant which inhibits allo-antigen-specific T cell responses. In addition, IL-10 is a strong endogenous anti-inflammatory cytokine. To investigate the role of IL-10 in the induction of acute GVHD following allogeneic bone marrow transplantation (BMT) we performed a prospective study on spontaneous IL-10 production by peripheral blood mononuclear cells (PBMNC) in 84 patients admitted for allogeneic BMT. High spontaneous IL-10 production by PBMNC at the time of admission and prior to any preparative treatment correlated with a subsequent low incidence of GVHD and transplant-related mortality (8%), as compared to patients with low or intermediate IL-10 production (50%, P < 0. 01). Our data demonstrate the prognostic significance of increased IL-10 production in BMT patients and suggest a major role of IL-10 in maintaining immunobalance in the setting of allogeneic BMT. Bone Marrow Transplantation (2000) 25, 237-241.

Adolescent↗
PubMed2000

Interferon alpha in combination with GM-CSF induces the differentiation of leukaemic antigen-presenting cells that have the capacity to stimulate a specific anti-leukaemic cytotoxic T-cell response from patients with chronic myeloid leukaemia.

Although interferon alpha (IFN-alpha) is able to induce haematological remission in 60-80% of patients with chronic myeloid leukaemia (CML) in early chronic phase, major cytogenetic remissions are only achievable in 30-40%. Recent clinical data suggest that the addition of granulocyte-macrophage colony-stimulating factor (GM-CSF) to IFN-alpha therapy can significantly improve the cytogenetic response in some patients, although the mechanism remains unknown. We hypothesized that the combination of GM-CSF and IFN-alpha induces the differentiation of dendritic cells, which subsequently stimulates a specific anti-leukaemic response. Monocytes from CML patients were cultured in GM-CSF and interleukin (IL)-4 (GM/IL-4)or in GM-CSF and IFN-alpha (GM/IFN-alpha). After 7 d, the number of cells exhibiting typical antigen-presenting cell (APC) morphology was equal in both groups, and fluorescence in situ hybridization (FISH) analysis confirmed that the APCs generated with GM/IFN-alpha were of leukaemic origin. Phenotypically, both sets of APCs expressed typical surface markers; however, CD86, CD83, CD11c, HLA-ABC and HLA-DR expression was significantly higher in the GM/IFN-alpha APCs, whereas CD1a expression was significantly lower. In mixed lymphocyte reactions (MLR), GM/IFN-alpha APCs stimulated the proliferation of allogeneic T cells significantly better than GM/IL-4 APCs. However, both groups of APCs stimulated autologous T-cell proliferation equally. Finally, we assessed the ability of GM/IFN-alpha APCs to induce a leukaemia-specific cytotoxic T-cell response. Some samples generated cytotoxic T lymphocytes (CTLs) that specifically lysed bcr-abl-positive target cells. These data show that the combination of GM-CSF and IFN-alpha, when used in vitro, induces the differentiation of malignant APCs with potent T-cell stimulatory capacity. Although there is no in vivo evidence to support these findings, it is possible that, when administered to CML patients, GM-CSF in combination with IFN-alpha results in the generation of highly stimulatory leukaemic APCs.

Antigen-Presenting Cells↗
PubMed2000

Expression of HSV-TK suicide gene in primary T lymphocytes: the dog as a preclinical model.

Expression of suicide genes (e.g. herpes simplex virus thymidine kinase,HSV-TK) in T cells is an appealing approach to regulate graft-versus-host disease in adoptive immunotherapy. Here we report the optimization of retroviral infection of canine T cells. Canine T cells were stimulated either with phytohemagglutinin (PHA, 2 microg/ml) for 24-72 hours or with 100 U/ml interleukin-2 for seven days. Stimulated cells were co-cultivated with irradiated virus-producing cells. Transduction efficiencies ranged from 4% to 45% using PG13, a gibbon ape leukemia virus envelope (env) pseudotyped packaging cell line. Infection of cells with GPenvAM12, expressing the amphotropic Moloney murine leukemia virus env, did not yield a satisfactory percentage of transduced cells. Enrichment of transduced cells was performed using immunoselection, and gave a purity of up to 98%. Transfusion of 1 x 10(6) transduced cells per kilogram body weight showed that transduced cells could convert mixed chimerism to 100% and transfer immunity to a specific antigen. Transduced cells were repeatedly detected in peripheral blood and bone marrow by polymerase chain reaction with primers specific for the HSV-TK gene. We have demonstrated the feasibility of using the canine model to study gene therapy as a preclinical model.

Animals↗
PubMed2000

Evidence of peripheral blood-derived, plastic-adherent CD34(-/low) hematopoietic stem cell clones with mesenchymal stem cell characteristics.

The hematopoietic system of vertebrates can be completely reconstituted with hematopoietic stem cells derived from the bone marrow, fetal liver, or cord blood, or even from peripheral-blood-derived cells. A cellular marker to identify those cells is the proteoglycan CD34, although we have shown that the earliest identifiable hematopoietic stem cell is a CD34(-) fibroblast-like cell which can differentiate into CD34(+) hematopoietic precursors. Peripheral blood mononuclear cells were isolated from the heparinized blood of a dog and incubated in tissue culture in the presence of interleukin 6. After 10-14 days, an adherent layer of fibroblast-like cells had developed and cells were immortalized using the SV-40 large T antigen. Cells were cloned and subcloned by measures of limiting dilution, and various fibroblast-like clones were established. These fibroblast-like cells either do not express the CD34 antigen or express CD34 on a low level, although transcribing CD34. The CD34(-/low) cells express osteocalcin as a mesenchymal cell marker. The fibroblast-like cells eventually differentiate spontaneously in vitro into CD34(+) precursors and show colony formation. Prior to autologous stem cell transplantation, one clone of choice (IIIG7) was transfected with a retroviral construct containing the green-fluorescence protein (GFP). The recipient dog was totally irradiated with 300 cGy and received a stem cell transplant with GFP-containing, immortalized, fibroblast-like monoclonal autologous stem cells (0.5 x 10(8)/kg dog). No additional growth factors were applied. The peripheral blood counts recovered after 23 days (WBC >500; platelets >10,000). A peripheral blood smear showed some dim but definite, although timely, limited expression of the GFP protein in nucleated peripheral blood cells just five weeks after transplantation. A bone marrow biopsy showed GFP-positive cells in the marrow cavity predominantly as "bone-lining cells."

Animals↗
PubMed2000

Impaired expression of the CD3-zeta chain in peripheral blood T cells of patients with chronic myeloid leukaemia results in an increased susceptibility to apoptosis.

In patients with myeloid malignancies, cell-mediated immunity is often suppressed, being most profound in those with advanced disease. Such immune dysfunction, as demonstrated in many patients with chronic lymphocytic leukaemia (CLL) and myelodysplastic syndrome (MDS), may, at least in part, be due to altered expression of the CD3-zeta chain, which is an important component of the T-cell receptor (TCR). We speculated that impaired expression of the TCR-zeta chain would be evident in peripheral blood T cells of patients with chronic myeloid leukaemia (CML) and that such an abnormality would result in an increased ex vivo susceptibility to apoptosis. In this study, we demonstrated that, compared with normal controls, zeta chain expression was significantly downregulated in all of the T-cell subsets (P < 0.009) in more than 90% of CML patients. In addition, there was a significantly lower expression of the CD3-epsilon chain (P < 0.001) in patients than in controls. In those patients with abnormal zeta chain expression, the proportion of lymphocytes with spontaneous DNA fragmentation, as determined by terminal deoxynucleotide transferase-mediated dUTP-biotin nick-end labelling (TUNEL) assays, was also significantly higher (P < 0.002) than controls. From all of the patients tested, it was possible to upregulate partially zeta chain expression and hence to reduce the susceptibility to apoptosis by cross-linking the T cells with interleukin (IL)-2, interferon (IFN)-alpha or immobilized CD3. In addition, such cross-linked T cells showed a significantly higher capacity to proliferate than the native CML T cells.

Adult↗
PubMed2000

Large-scale N-ethyl-N-nitrosourea mutagenesis of mice--from phenotypes to genes.

The most important tool for obtaining insight into the function of genes is the use of mutant model organisms. Homologous recombination in embryonic stem cells allows the systematic production of mouse mutants for any gene that has been cloned. Gene trap strategies have been designed to interrupt even unknown genes which are tagged by the inserted vector and can be characterised structurally and functionally. Complementary to such 'gene-driven' approaches, 'phenotype-driven' approaches are necessary to identify new genes or gene products through a search for mutants with specific defects, uncovering the function of genetic pathways in physiological and pathological processes. Mutagenesis using the alkylating agent N-ethyl-N-nitrosourea (ENU) is a powerful approach for the production of such mouse mutants. Since ENU induces mainly point mutations in premeiotic spermatogonia, this strategy allows the production of multiple alleles of a particular gene, which is pivotal for a fine tuned analysis of its function.

Alkylating Agents↗
PubMed1999

Interferon-alpha before allogeneic bone marrow transplantation in chronic myelogenous leukemia does not affect outcome adversely, provided it is discontinued at least 90 days before the procedure.

The influence of interferon-alpha (IFN) pretreatment on the outcome after allogeneic bone marrow transplantation (BMT) in chronic myelogenous leukemia (CML) is controversial. One goal of the German randomized CML Studies I and II, which compare IFN +/- chemotherapy versus chemotherapy alone, was the analysis of whether treatment with IFN as compared to chemotherapy had an influence on the outcome after BMT. One hundred ninety-seven (23%) of 856 Ph/bcr-abl-positive CML patients were transplanted. One hundred fifty-two patients transplanted in first chronic phase were analyzed: 86 had received IFN, 46 hydroxyurea, and 20 busulfan. Forty-eight patients (32%) had received transplants from unrelated donors. Median observation time after BMT was 4.7 (0.7 to 13.5) years. IFN and chemotherapy cohorts were compared with regard to transplantation risks, duration of treatments, interval from discontinuation of pretransplant treatment to BMT, conditioning therapy, graft-versus-host disease prophylaxis and risk profiles at diagnosis and transplantation, and IFN cohorts also with regard to performance and resistance to IFN. Outcome of patients receiving related or unrelated transplants pretreated with IFN, hydroxyurea, or busulfan was not significantly different. Five-year survival after transplantation was 58% for all patients (57% for IFN, 60% for hydroxyurea and busulfan patients). The outcome within the IFN group was not different by duration of prior IFN therapy more or less than 5 months, 1 year, or 2 years. In contrast, a different impact was observed in IFN-pretreated patients depending on the time of discontinuation of IFN before transplantation. Five-year survival was 46% for the 50 patients who received IFN within the last 90 days before BMT and 71% for the 36 patients who did not (P =.0057). Total IFN dosage had no impact on survival after BMT. We conclude that outcome after BMT is not compromised by pretreatment with IFN if it is discontinued at least 3 months before transplantation. Clear candidates for early transplantation should not be pretreated with IFN.

Adolescent↗
PubMed1999

Malignant neoplasms in long-term survivors of bone marrow transplantation. Late Effects Working Party of the European Cooperative Group for Blood and Marrow Transplantation and the European Late Effect Project Group.

BACKGROUND: Patients who receive bone marrow transplants have increased risk for new malignant conditions because of several risk factors, including conditioning with radiation and chemotherapy, immune stimulation, and malignant primary disease. The occurrence of and risk factors for malignant neoplasm in long-term survivors must be assessed. OBJECTIVE: To determine the risk and define potential risk factors for new malignant conditions in long-term survivors after marrow transplantation. DESIGN: Retrospective multicenter study. SETTING: Study of the Late Effects Working Party with 45 transplantation centers cooperating in the European Cooperative Group for Blood and Marrow Transplantation. PATIENTS: 1036 consecutive patients who underwent transplantation for leukemia, lymphoma, inborn diseases of the hematopoietic and immune systems, or severe aplastic anemia. Transplantation was done before December 1985, and patients had survived more than 5 years. MEASUREMENTS: Reports on malignant neoplasms were evaluated, and the incidence was compared to that in the general population. Patient age and sex, primary disease and status at transplantation, histocompatibility of the donor, conditioning regimen, type of prophylaxis of graft-versus-host disease, development of acute and chronic graft-versus-host disease, and treatment of chronic graft-versus-host disease were evaluated as variables. RESULTS: Median follow-up since transplantation was 10.7 years (range, 5 to 22.1 years). Malignant neoplasms were seen in 53 patients; the actuarial incidence (+/- SE) was 3.5% +/- 0.6% at 10 years and 12.8% +/- 2.6% at 15 years. The rate of new malignant disease was 3.8-fold higher than that in an age-matched control population (P < 0.001). The most frequent malignant diseases were neoplasms of the skin (14 patients), oral cavity (7 patients), uterus (including cervix) (5 patients), thyroid gland (5 patients), breast (4 patients), and glial tissue (3 patients). Median age of patients and their donors was 21 years. Malignant neoplasms were more frequent in older patients and in patients with chronic graft-versus-host disease. Older patient age and treatment of chronic graft-versus-host disease with cyclosporine were significant risk factors for new malignant neoplasms after bone marrow transplantation. CONCLUSIONS: The spectrum of neoplasms and immunosuppressive treatment with cyclosporine for chronic graft-versus-host disease as dominant risk factors indicate that immunosuppression is the major cause of malignant neoplasms in patients receiving marrow transplants.

Adolescent↗
PubMed1999

Risk of lymphoproliferative disorders after bone marrow transplantation: a multi-institutional study.

We evaluated 18,014 patients who underwent allogeneic bone marrow transplantation (BMT) at 235 centers worldwide to examine the incidence of and risk factors for posttransplant lymphoproliferative disorders (PTLD). PTLD developed in 78 recipients, with 64 cases occurring less than 1 year after transplantation. The cumulative incidence of PTLD was 1.0% +/- 0.3% at 10 years. Incidence was highest 1 to 5 months posttransplant (120 cases/10,000 patients/yr) followed by a steep decline to less than 5/10,000/yr among >/=1-year survivors. In multivariate analyses, risk of early-onset PTLD (<1 year) was strongly associated (P <.0001) with unrelated or human leukocyte antigen (HLA) mismatched related donor (relative risk [RR] = 4.1), T-cell depletion of donor marrow (RR = 12.7), and use of antithymocyte globulin (RR = 6.4) or anti-CD3 monoclonal antibody (RR = 43.2) for prophylaxis or treatment of acute graft-versus-host disease (GVHD). There was a weaker association with the occurrence of acute GVHD grades II to IV (RR = 1.9, P =.02) and with conditioning regimens that included radiation (RR = 2.9, P =.02). Methods of T-cell depletion that selectively targeted T cells or T plus natural killer (NK) cells were associated with markedly higher risks of PTLD than methods that removed both T and B cells, such as the CAMPATH-1 monoclonal antibody or elutriation (P =.009). The only risk factor identified for late-onset PTLD was extensive chronic GVHD (RR = 4.0, P =.01). Rates of PTLD among patients with 2 or >/=3 major risk factors were 8.0% +/- 2.9% and 22% +/- 17.9%, respectively. We conclude that factors associated with altered immunity and T-cell regulatory mechanisms are predictors of both early- and late-onset PTLD.

Adolescent↗
PubMed1999

Long-term survival and late deaths after allogeneic bone marrow transplantation. Late Effects Working Committee of the International Bone Marrow Transplant Registry.

BACKGROUND AND METHODS: It is uncertain whether mortality rates among patients who have undergone bone marrow transplantation return to the level of the mortality rates of the general population. We analyzed the characteristics of 6691 patients listed in the International Bone Marrow Transplant Registry. All the patients were free of their original disease two years after allogeneic bone marrow transplantation. Mortality rates in this cohort were compared with those of an age-, sex-, and nationality-matched general population. Cox proportional-hazards regression was used to identify risk factors for death more than two years after transplantation (late death). RESULTS: Among patients who were free of disease two years after transplantation, the probability of living for five more years was 89 percent (95 percent confidence interval, 88 to 90 percent). Among patients who underwent transplantation for aplastic anemia, the risk of death by the sixth year after transplantation did not differ significantly from that of a normal population. Mortality remained significantly higher than normal throughout the study among patients who underwent transplantation for acute lymphoblastic leukemia or chronic myelogenous leukemia and through the ninth year among those who underwent transplantation for acute myelogenous leukemia. Recurrent leukemia was the chief cause of death among patients who received a transplant for leukemia, whereas chronic graft-versus-host disease was the chief cause among those who received a transplant for aplastic anemia. Advanced, long-standing disease before transplantation and active chronic graft-versus-host disease were important risk factors for late death. CONCLUSIONS: In patients who receive an allogeneic bone marrow transplant as treatment for acute myelogenous or lymphoblastic leukemia, chronic myelogenous leukemia, or aplastic anemia and who are free of their original disease two years later, the disease is probably cured. However, for many years after transplantation, the mortality among these patients is higher than that in a normal population.

Adolescent↗
PubMed1999

Final height of patients who underwent bone marrow transplantation for hematological disorders during childhood: a study by the Working Party for Late Effects-EBMT.

Few data are available on the long-term effect of bone marrow transplantation (BMT) on growth. This study examines those factors that play a role in the final height outcome of patients who underwent BMT during childhood. Data on 181 of 230 patients with aplastic anemia, leukemias, and lymphomas who had BMT before puberty (mean age, 9.8 +/- 2.6 years) and who had reached their final height were analyzed. An overall decrease in final height standard deviation score (SDS) value was found compared with the height at BMT (P < 10(7)) and with the genetic height (P < 10(7)). Girls did better than boys, and the younger in age the person was at time of BMT, the greater the loss in height. Previous cranial irradiation + single-dose total body irradiation (TBI) caused the greatest negative effect on final height achievement (P < 10(4)). Fractionation of TBI reduces this effect significantly and conditioning with busulfan and cyclophosphamide seems to eliminate it. The type of transplantation, graft-versus-host disease, growth hormone, or steroid treatment did not influence final height. Irradiation, male gender and young age at BMT were found to be major factors for long-term height loss. Nevertheless, the majority of patients (140/181) have reached adult height within the normal range of the general population.

Adolescent↗
PubMed1999

Bispecific antibody fragments with CD20 X CD28 specificity allow effective autologous and allogeneic T-cell activation against malignant cells in peripheral blood and bone marrow cultures from patients with B-cell lineage leukemia and lymphoma.

Bispecific antibodies directed against tumor-associated target antigens and to surface receptors mediating T-cell activation, such as the TCR/CD3 complex and the costimulatory receptor CD28, are capable of mediating T-cell activation resulting in tumor cell killing. In this study, we used the B-cell-associated antigens CD19 and CD20 as target structures on human leukemic cells. We found that a combination of bispecific antibody fragments (bsFab2) with target x CD3 and target x CD28 specificity induces vigorous autologous T-cell activation and killing of malignant cells in peripheral blood and bone marrow cultures from patients with chronic lymphocytic leukemia and follicular lymphoma. The bsFab2 targeting CD20 were considerably more effective than those binding to CD19. The colony-forming capacity of treated bone marrow was impaired due to large amounts of tumor necrosis factor alpha produced during bsFab2-induced T-cell activation. Neutralizing tumor necrosis factor alpha antibodies were found to reverse this negative effect without affecting T-cell activation and tumor cell killing. CD20 x CD28 bsFab2, when used alone rather than in combination, markedly improved the recognition of leukemic cells by allogeneic T cells. Therefore, these reagents may be capable of enhancing the immunogenicity of leukemic cells in general and, in particular, of increasing the antileukemic activity of allogeneic donor buffy coat cells in relapsed bone marrow transplanted patients.

Antibodies, Monoclonal↗
PubMed1999

Proteolytic activity in the yolk sac membrane of quail eggs.

Extraembryonal degradation of yolk protein is necessary to provide the avian embryo with required free amino acids during early embryogenesis. Screening of proteolytic activity in different compartments of quail eggs revealed an increasing activity in the yolk sac membrane during the first week of embryogenesis. In this tissue, the occurrence of cathepsin B, a lysosomal cysteine proteinase, and cathepsin D, a lysosomal aspartic proteinase, has been described recently (Gerhartz et al., Comp Biochem Physiol, 118B:159-166, 1997). Determination of cathepsin B-like and cathepsin D-like proteolytic activity in the yolk sac membrane indicated a significant correlation between growth of the yolk sac membrane and proteolytic activity, shown by an almost constant specific activity. Both proteinases could be localized in the endodermal cells, which are in direct contact to the yolk. The concentration of proteinases in the endodermal cells appears to be almost unaltered in the investigated early stage of quail development, whereas the amount of endodermal cells increases rapidly, seen by a complicated folding of the yolk sac membrane. In the same cells quail cystatin, a potent inhibitor of quail cathepsin B (Ki 0.6 nM), has been localized at day 8 of embryonic development. Approximately at this stage of development, the quail embryo stops metabolizing yolk. In conclusion, it is strongly indicated that the amount of available free amino acids, produced by proteolytic degradation and supporting embryonic growth, is regulated by the growth of the yolk sac membrane.

Animals↗
PubMed1999

Nutritional status and growth after bone marrow transplantation (BMT) during childhood: EBMT Late-Effects Working Party retrospective data. European Group for Blood and Marrow Transplantation.

The European Group for Blood and Marrow Transplantation (EBMT) Late-Effects Working Party collected data on patients who survived more than 5 years after BMT. Height at transplant and at the latest follow-up examination were evaluated in 79/258 subjects who were below the age of 15 at BMT. A significant decrease in height-standard deviation score (SDS) was observed in leukemic children conditioned with total body irradiation (TBI) and in those who received both cranial irradiation and TBI. The majority of these patients, however, received single-dose TBI (28/41). A significant decrease in height-SDS was also seen in children who received thoraco-abdominal irradiation suggesting that the deleterious effect of irradiation on growth after BMT is not entirely due to injury to cranial neuroendocrine structures, but also probably due to damage to bone epiphyses, thyroid and gonads. A non-significant decrease in height was observed in children transplanted using chemotherapy alone. Nutritional status, expressed as body-mass index (BMI), was found unchanged in the adult group (n = 158). A significant increase in BMI was observed in the younger patients (n = 88), which parallels the normal increase in BMI observed during childhood. This suggests that on long-term analysis, a good nutritional status is maintained in patients undergoing BMT at any age.

Adolescent↗
PubMed1999

Secondary leukaemia and myelodysplasia after autografting for lymphoma: results from the EBMT. EBMT Lymphoma and Late Effects Working Parties. European Group for Blood and Marrow Transplantation.

Between 1978 and 1996 more than 7500 lymphoma transplants have been reported to the European Bone Marrow Transplantation (EBMT) Lymphoma Registry. This has been examined to establish the incidence of secondary leukaemia and myelodysplasia and to relate this to possible prognostic factors. 131 centres representing 4998 patients responded to a questionnaire. This identified 66 patients with post transplant myelodysplastic syndrome (MDS)/acute myeloid leukaemia (AML). The actuarial risk for MDS/AML at 5 years post-transplant (+/-95% CI) was 4.6% (3.1-6.8) for Hodgkin's disease and 3.0% (2.0-4. 3) for non-Hodgkin's lymphoma. Multivariate analysis for all patients demonstrated an effect of age at transplant, radiotherapy at conditioning, number of transplants and interval between diagnosis and transplant as risk factors. For patients with NHL, grade of histology was important (low grade > intermediate or high-grade); for Hodgkin's disease, female sex was identified as a risk factor. These findings suggest that the incidence of MDS/AML may not be greater following an autograft than after conventional chemotherapy.

Adolescent↗
PubMed1999

Efficacy and toxicity of IFN-alpha2b combined with cytarabine in chronic myelogenous leukaemia.

Newly diagnosed chronic myelogenous leukaemia (CML) patients (n = 65) were treated with interferon (IFN)-alpha2b (5 x 106 IU/d s.c.) combined with monthly courses of cytarabine (20 mg/d s.c. for 14 d). Median age of patients enrolled was 45 years. The endpoints of the study were clinical efficacy and toxicity. The survival rates at 3 years and 5 years were 77% and 56%, respectively. The rate of complete haematological response was 60%. Evaluation of cytogenetic response was available in 29/65 patients. A complete cytogenetic response was seen in 3/29 patients (10%). W.H.O. toxicity grade 3-4 occurred in only 22/523 evaluable treatment cycles. Since the study protocol required intermittent or definitive discontinuation of cytarabine in case of moderate leucopenia (white blood cells (WBC) <5 x 109/l), combined cytopenia (WBC < 5 x 109/l, platelets <100 x 109/l), and isolated moderate thrombocytopenia (<100 x 109/l), the drug had to be discontinued temporarily or definitively in 200 cycles and the dose of cytarabine had to be reduced in 35 cycles. Thus, only 25% of the planned dose of cytarabine could be administered. At this dosage it would appear that cytarabine had no effect on survival and did not improve remission rates. We conclude that a clinical benefit for the addition of cytarabine to the treatment of CML with IFN might only be achieved by the administration of a higher cumulative dose of cytarabine, suggesting that lower leucocyte counts of 2-4 x 109/l have to be tolerated.

Adolescent↗