4-hydroperoxy-cyclophosphamide mediates caspase-independent T-cell apoptosis involving oxidative stress-induced nuclear relocation of mitochondrial apoptogenic factors AIF and EndoG.

Apoptosis is a major mechanism of treatment-induced T-cell depletion in leukemia and autoimmune diseases. While 'classical' apoptosis is considered to depend on caspase activation, caspase-independent death is increasingly recognized as an alternative pathway. Although the DNA-damaging drug cyclophosphamide (CY) is widely used for therapy of hematological malignancies and autoimmune disorders, the molecular mechanism of apoptosis induction remains largely unknown. Here, we report that treatment of Jurkat, cytotoxic, and primary leukemic T cells with an activated analog of CY, 4-hydroperoxy-cyclophosphamide (4-OOH-CY), induces caspase activation and typical features of apoptosis, although cell death was not prevented by caspase inhibition. Also depletion of murine thymocytes and splenocytes after CY treatment in vivo was not inhibited by Z-Val-Ala-DL-Asp-fluoromethylketone (Z-VAD.fmk). Caspase-8 and receptor-induced protein (RIP) were dispensable for 4-OOH-CY-mediated apoptosis, while overexpression of Bcl-2 was partially protective. 4-OOH-CY treatment induced reactive oxygen species production, upregulation of Bax, and nuclear relocation of the mitochondrial factors apoptosis-inducing factor (AIF) and endonuclease G (EndoG). The antioxidant N-acetyl-L-cysteine substantially inhibited conformational changes of Bax, loss of mitochondrial membrane potential, nuclear relocation of mitochondrial factors, and apoptosis induction in 4-OOH-CY-treated T cells. These results strongly indicate that oxidative damage-induced nuclear translocation of AIF and EndoG in 4-OOH-CY-treated T cells might represent an alternative death pathway in the absence of caspase activity.

Coincidence of recurrent hemiparesis and detection of ALL in a 4-year-old girl: one or two diseases?

Stroke like symptoms in children such as hemiparesis are often associated with infection, cranial trauma, cardiac anomalies or sickle cell disease. In childhood leukemia, stroke like symptoms at presentation are rare and normally caused by cerebral bleedings. Here we report a patient who presented with classical stroke symptoms and hemiparesis prior to the diagnosis of acute lymphoblastic leukemia without proven CNS infiltration by leukemic cells. In general, acute leukemia or cerebral lymphoma do not lead to extensive defects of brain tissue. This unusual case suggests that acute lymphoblastic leukemia may present with stroke like CNS symptoms including hemiparesis.

Apoptosis induction in peripheral leukemia cells by remission induction treatment in vivo: selective depletion and apoptosis in a CD34+ subpopulation of leukemia cells.

In vitro studies demonstrating the induction of programmed cell death by cytotoxic drugs used in anticancer chemotherapy suggested that antileukemic treatment eliminates leukemia cells by apoptosis. We therefore analyzed apoptosis induction and activation of apoptosis signaling molecules in patients receiving remission induction treatment for AML and ALL during the initial phase of leukemia cell reduction. A coexistence of distinct populations of CD34(+) and CD34(-) leukemia cells could be identified. During chemotherapy, CD34(+) leukemia cells were more rapidly depleted than CD34(-) cells. Furthermore, a significant increase in leukemia cell apoptosis ex vivo was detected in CD34(+) cells, while no such increase was observed in the CD34(-) subpopulation, suggesting that CD34(+) leukemia cells are the main targets for apoptosis induction through antileukemic treatment. No alterations in Bax and Bcl-2 expression were found during in vivo chemotherapy, and CD95 expression and sensitivity remained low, indicating the induction of apoptosis independent of the CD95 system or regulation of protein levels of Bax and Bcl-2. The data suggest that analysis of leukemia cell subpopulations is required for further identification of apoptosis signaling molecules relevant for response to treatment and assessment of drug efficacy in vivo and in vitro.

Duration of first remission predicts remission rates and long-term survival in children with relapsed acute myelogenous leukemia.

Although treatment of childhood acute myelogenous leukemia (AML) has substantially improved in the last 15 years, in nearly half of the patients disease recurs. The aim of this study was to establish the prognosis of relapsed childhood AML and to identify prognostic factors for achievement of second remission and survival. From February 1988 to July 1996, 134 children with first relapse of AML were reported to the study center of the AML-BFM group. 102 patients treated intensively to induce second remission were prospectively followed. With various regimens, complete remission was achieved in 52 of 102 patients (51%), 27 children were alive in median 2.5 years (range, 0.4-7 years) after relapse. Disease-free survival was observed in seven of 16 patients transplanted from a matched sibling donor, one of four after matched unrelated bone marrow transplantation, 10 of 22 after autologous transplantation and five of nine patients after chemotherapy alone (two patients were lost to follow-up). Time until relapse reflecting the duration of first remission is the only variable correlating CR and survival rates. Defining early relapse as less than 1.5 years from diagnosis to relapse resulted in a 5-year survival of 10%, s.e. 5% for early relapses and 40%, s.e. 10% for late relapses (P-logrank test, 0.0001). Duration of first remission is a strong predictor for achievement of second CR and survival. It should be considered in reporting results of experimental therapies.

CD95 (APO-1/FAS)-mediated apoptosis in cytokine-activated hematopoietic cells.

Elimination of peripheral T cells is crucially regulated via apoptosis through CD95 (APO-1/Fas) receptor ligand interaction. Because homeostasis in hematopoietic cells may also involve the CD95 system, we analyzed CD95 expression and sensitivity to CD95-induced apoptosis in human bone marrow cells. During hematopoiesis CD95 is differentially expressed on distinct cell types and at different maturational stages with an increase in receptor density from early CD34+ stem cells to maturing progenitor cells. Incubation of bone marrow cells with anti-APO-1 (anti-CD95) induces apoptosis in maturing erythroblasts and neutrophil progenitors (10-19%) and to a lesser extent in stem cells and myeloblast/proerythroblasts (4-9%). On in vitro culture, CD95 expression is particularly upregulated on activated CD71+ myeloid progenitors. Hematopoietic cytokines (stem cell factor, interleukin-3, granulocyte macrophage colony-stimulating factor [GM-CSF], and granulocyte-colony-stimulating factor [G-CSF] contribute to upregulation of CD95 on bone marrow cells. CD95-induced apoptosis in activated progenitors was markedly enhanced by activating cytokines. Thus cytokines known to mediate proliferation, survival, and maturation, in hematopoiesis do not prevent, but rather facilitate negative growth regulation via the CD95 pathway in activated cells. Deregulation of the CD95 system may provide a molecular basis for the development of bone marrow failure or immune-mediated cytopenia. Defects in the CD95 pathway may contribute to the development of hematopoietic malignancy by abrogating CD95-mediated growth control of activated cells.

[Ocular findings in Desferal therapy]. / Okuläre Befunde bei Desferaltherapie.

Desferrioxamine (DFO) is the most important drug in the treatment of thalassemia major and other hematological diseases requiring regular transfusion. It eliminates excessive ferritin by building up chelate complexes. Different mechanisms of possible DFO toxicity are induction of oxidation, damage of the blood-retina barrier, or reduction in other metalloions (Cu2+, Zn2+). The objective of the present study was to evaluate the ocular side effects of DFO treatment. We prospectively examined 17 patients aged 5 to 25 years, all of them treated with DFO. Visual acuity, pupillary reaction, anterior segment, lens and fundus were checked. If possible, visual fields, color vision, dark adaptation, stereoscopic vision, and contrast sensitivity were investigated. Lens opacities were found in 41% (7/17), changes in the retinal pigment epithelium in 35% (6/17), tortuosity of retinal vessels in 24% (4/17), dilation and sheathing of the retinal vessels in 18% (3/17), defects in color vision in 29% (5/17), and abnormal dark adaptation in 18% (3/17) of the patients. The oculotoxicity of DFO is dose-dependent. Major side effects like depression of the visual acuity are partially reversible after discontinuing the therapy. Regular ophthalmological check-ups are therefore necessary.

[Beta-thalassemia in Germany. Results of cooperative beta-thalassemia study]. / beta-Thalassämie in Deutschland. Ergebnisse der kooperativen beta-Thalassämie-Studie.

At present, about 300 patients with thalassemia major are living in Germany. Starting in 1991, a multicenter study in Germany has concentrated on identifying all patients suffering from thalassemia as well as on establishing a uniform therapy protocol including follow-up diagnostic procedures. After six years of study, the data of 198 patients suffering from thalassaemia major were analysed. The majority of these patients originate from endemic regions around the Mediterranean Sea. The patient's median age is 13.8 years (range 1-37.5 yrs.). At present, about 20% of patients are older than 21 years. Regarding transfusion therapy, a shortening of the average transfusion interval to 3 weeks in most cases occurred. Throughout the entire period, median baseline haemoglobin concentrations of 10.0 g/dl could be observed. The evaluation of serum ferritin levels revealed considerable differences depending on patients age. 60% of patients in the first decade of life showed good therapeutic results with serum ferritin levels below 1800 ng/ml. In contrast, 52% of patients older than ten years presented with ferritin levels above 2500 ng/ml. During the observation, a decreasing number of patients with ferritin levels above 2500 ng/ml was observed in patients aged 15 to 21 years of age. The situation of patients aged 9 to 15 years proved to be more problematic. More than half of all treated patients presented with siderotic complications as cardiac disease in 13%, liver disease in 21%, impaired glucose metabolism in 14%, hypothyroidism in 24% and hypogonadism in 59% of all patients. These values did not change considerably during the observation apart from an increase of cardiac disorders to 20%. Since the situation concerning siderosis and the lack of compliance proved to be particularly difficult in adolescent patients, further efforts has to concentrate on this age group.

[German multicenter thalassemia study. Concept and initial results]. / Multizentrische deutsche Thalassämie-Studie. Konzept und erste Ergebnisse.

At present more than 300 children and adolescents with Thalassaemia major are living in the FRG. The purpose of this project is--for the first time--to apply a standardized therapy protocol to these patients, to prove its effectivity and study side-effects. The multi-center study started in April 1991. The therapy is based on periodical transfusion of erythrocytes in order to keep haemoglobin (Hb) concentration (= basic Hb-value) above 10.5 g/dl, and daily application of Desferal, 40 mg/kg bw s.c. for iron elimination. Until Nov. 30, 1991 74 patients from 31 different childrens hospitals entered the study. Preliminary results after evaluation of the basic questionnaires can be summarized as follows: 1. The majority of patients if not too old to highly profit from improvement of therapy; 2. In 40.9% of these patients HbF concentration was higher than 15%, which indicates a suboptimal transfusion therapy; 3. At least 30% of patients need intensified iron elimination. Even these preliminary data demonstrate the necessity to improve the therapy of Thalassaemia major in Germany. The goal is to include all affected patients in the study and so optimize long term results concerning quality of life and prognosis.

Epidemiological situation and treatment of patients with thalassemia major in Germany: results of the German multicenter beta-thalassemia study.

At present, about 300 patients in Germany suffer from thalassemia major. In 1990, a multicenter study was introduced to identify all thalassemic patients in Germany as well as to establish a uniform therapy protocol, including follow-up diagnostic procedures. After 6 years of study, the data of 203 patients were analyzed. The majority originate from endemic regions around the Mediterranean Sea. The median age of the patients is 13.8 years (range 1-37.5 years). At present, about 20% of the patients are older than 21 years. Regarding transfusion therapy, a shortening of the average transfusion interval to 3 weeks in most cases occurred. Throughout the entire period, median baseline hemoglobin concentrations of 10.0 g/dl were observed. The evaluation of serum ferritin levels revealed considerable differences, depending on the patients' age. Thalassemic patients in the first decade of life generally presented with good therapeutic results; serum ferritin levels were below 1800 ng/ml in 76/102 patients (75%) upon entry into the study. In contrast, 51/98 patients (52%) older than 10 years had ferritin levels above 2500 ng/ml. More than half of all treated patients presented with siderotic complications such as cardiac disease in 20/157 (13%), liver disease in 32/157 (21%), impaired glucose metabolism in 22/157 (14%), hypogonadism in 39/66 (59%), and hypothyroidism in 38/157 (24%) who were under treatment at the time of first survey. Since the situation concerning siderosis and the lack of compliance proved to be particularly difficult with adolescent patients, further efforts should concentrate on this age-group.

Identification of deficient mitochondrial signaling in apoptosis resistant leukemia cells by flow cytometric analysis of intracellular cytochrome c, caspase-3 and apoptosis.

Deficient activation of apoptosis signaling pathways may be responsible for treatment failure of malignant diseases. In primary leukemia samples the detection of deficient mitochondrial apoptosis signaling would enable identification of chemo-resistant cells. To investigate the key events of apoptosis at the mitochondrial level, we developed a flow cytometric method for simultaneous detection of mitochondrial cytochrome c release and caspase-3 processing using conformation sensitive monoclonal antibodies. This method proved to identify deficient mitochondrial apoptosis signaling in leukemia cells overexpressing Bcl-2 by a pattern of apoptosis resistance, deficient cytochrome c reduction and partial processing of caspase-3. In primary leukemia cells, reduction of cytochrome c and caspase-3 activation was induced by treatment with anticancer drugs in vitro. In leukemia cells of a patient with resistant disease, a pattern of deficient apoptosis signaling as in Bcl-2 transfected cells was observed, suggesting that deficient mitochondrial signaling contributed to the clinical phenotype of drug resistance in this patient. Flow cytometric analysis of mitochondrial apoptosis signaling may provide a useful tool for the prediction of drug resistance and treatment failure in primary leukemia.

[Prognosis of children with acute myelocytic leukemia after first relapse]. / Prognose von Kindern mit AML nach dem ersten Rezidiv.

UNLABELLED: Nearly 40% of children treated within the AML BFM studies experience recurrence of their disease after having achieved remission. In our retrospective analysis we tried to estimate prognosis after relapse in children treated with intensive relapse regimens and studied the impact of prognostic factors for second remission and survival. PATIENTS: 102 patients suffering from first relapse were treated intensively according to the relapse protocols BFM REZ91 and REZ93 or intensive salvage therapy consisting of double induction with high dose Ara-C, mitoxantrone and VP-16. Once in CR, patients continued to receive a 6-week consolidation and either allogeneic or autologous bone marrow transplantation (BMT). RESULTS: Time to relapse was in median 1.1 years, range 0-8 years. Fifty-two of 102 pts. (51%) achieved 2nd remission (CR), 10 (10%) partial remission, 37 (36%) were nonresponders, and 3(3%) died early during salvage therapy. Twenty-seven were still in CR, median 2.5 years, range 0.4-7.0 years, with an overall survival of 21%, SE 5% after 5 years. The response and survival rate was similar in all treatment groups. Fifty patients were transplanted, 43 being in 2nd CR, and 7 with residual blasts. Twenty-seven patients received an allograft: Twenty-one from a matched sibling (MSD), 1 from a haploid and 5 from a matched unrelated donor (MUD); 23 received an autograft. None of the patients transplanted in partial remission survived. Whereas 7 of 16 patients were alive after MSD in 2nd CR, 1 after haploid BMT. Four of 5 patients died after MUD BMT. Multivariate risk factor analysis revealed duration until relapse to be the most important factor for survival after relapse. The maximum risk-ratio was obtained at a threshold value of 1.5 years after diagnosis resulting in a 5-year survival of 10%, SE 5% for early relapse, and 40%, SE 10% for late relapse, p logrank 0.0001. CONCLUSION: Intensive relapse regimens can induce a 2nd CR in half of the patients. Children with late relapse (> 1.5 years after diagnosis) have a realistic chance for longtime survival.

Therapy of childhood acute myelogenous leukemias.

Acute myelogenous leukemia (AML) accounts for approximately 20% of acute leukemias in children. Although AML is more resistant to chemotherapy than acute lymphoblastic leukemia (ALL), significant progress in improving outcome for AML patients has been achieved over the past 15 years. This can be attributed to intensification of chemotherapy, increased use of bone marrow transplantation, and improved supportive care. Thus 30-50% of children with AML achieve long-term event-free survival with current treatment strategies [61, 66, 85, 96]. This review gives an overview about the evolution of and rationale for current pediatric treatment protocols, with special emphasis on the German Berlin-Frankfurt-Münster (BFM) studies, and discusses new directions for the future.

Activation of apoptosis pathways in peripheral blood lymphocytes by in vivo chemotherapy.

In addition to myelosuppression, anticancer drugs cause rapid and persistent depletion of lymphocytes, possibly by direct apoptosis induction in mature T and B cells. Induction of apoptosis regulators was analyzed in peripheral blood lymphocytes from pediatric patients undergoing first-cycle chemotherapy for solid tumors. In vivo chemotherapy induced a significant increase in lymphocyte apoptosis ex vivo. The activation of initiator caspase-8 and effector caspase-3 and the cleavage of caspase substrates was detected 12 to 48 hours after the onset of therapy. Caspase inhibition by Z-VAD-fmk did not reduce ex vivo lymphocyte apoptosis in all patients, indicating the additional involvement of caspase-independent cell death. No evidence for the involvement of activation-induced cell death was found in the acute phase of lymphocyte depletion as analyzed by activation marker expression and sensitivity for CD95 signaling. Lymphocyte apoptosis in vivo appeared to be predominantly mediated by the mitochondrial pathway because a marked decrease of mitochondrial membrane potential (DeltaPsi(M)) was detected after 24 to 72 hours of treatment, preceded by the increased expression of Bax. Interestingly, despite the use of DNA-damaging agents, p53 remained completely undetectable throughout treatment. In contrast, in vitro treatment with cytarabine and etoposide induced p53 protein, CD95 receptor expression, CD95 sensitivity, and CD95 receptor-ligand interaction in stimulated cycling lymphocytes, but no such induction was seen in resting cells. These data suggest that chemotherapy-induced lymphocyte depletion involves distinct mechanisms of apoptosis induction, such as direct mitochondrial and caspase-dependent pathways in resting cells and p53-dependent pathways in cycling lymphocytes.

[Treatment of recurrence of acute myeloid leukemia in childhood. A retrospective analysis of recurrence in the AML-BFM-83 study]. / Rezidivbehandlung bei akuter myeloischer Leukämie im Kindesalter. Eine retrospektive Analyse der in der Studie AML-BFM-83 aufgetretenen Rezidive.

Complete remission (CR) rates of 80% are achieved with the AML-BFM protocols but one third of patients relapse within the first three years. There are few reports of treatment of relapsed childhood AML, and these deal with the evaluation of new drugs for frontline therapy. We performed a retrospective analysis to investigate how patients previously treated with the AML-BFM-83 protocol were treated after relapse and how many long term remissions were achieved. 48 of 139 patients relapsed after having achieved complete remission with the AML-BFM-83 protocol which consists of continous infusion of ARA-C 100 mg/m2 day 1-2, ARA-C 200 mg/m2 day 3-8, Daunorubicin 60 mg/m2 day 3, 4, and 5, and VP-16 150 mg/m2 day 6, 7, and 8, and an 8 week consolidation therapy consisting of Prednisolone, Thioguanine, Vincristine, ADR, ARA-C, Cyclophosphamide, intrathecal ARA-C and cranial irradiation followed by maintenance therapy. Duration of first remission ranged from 1.5 months to 66.3 months. Excluding 5 children with either isolated or combined extramedullary relapses and another 4 patients for missing data, 39 children were evaluable. 20 children received no therapy or palliative therapy while 16 patients received chemotherapy and another 3 children were transplanted in relapse. Although 9 different intensive chemotherapy regimens were used for reinduction, a high number (12 of 16 = 75%) of second complete remissions was achieved. Several therapeutic options were used to maintain a second remission: regular maintenance therapy (7 patients), allogeneous bone marrow transplantation (BMT) (2 patients), autologous BMT (3 patients).(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics of native Escherichia coli asparaginase (Asparaginase medac) and hypersensitivity reactions in ALL-BFM 95 reinduction treatment.

Repeated asparaginase treatment has been associated with hypersensitivity reactions against the bacterial macromolecule in a considerable number of patients. Immunological reactions may range from anaphylaxis without impairment of serum asparaginase activity to a very fast decline in enzyme activity without any clinical symptoms. Previous investigations on a limited number of patients have shown high interindividual variability of asparaginase activity time courses and hypersensitivity reactions in about 30% of patients during reinduction treatment. Therefore, monitoring of reinduction treatment was performed prospectively in 76 children with newly diagnosed acute lymphoblastic leukaemia (ALL). According to the ALL-Berlin-Frankfurt-Münster (BFM) 95 protocol, 10 000 U/m2 body surface area of native Escherichia coli asparaginase (Asparaginase medac) was given on d 8, 11, 15 and 18. In 45/76 children, trough and peak activities were determined with every dose, and also on d 4 and d 11 after the last administration. Data on asparaginase activity were not available from the remaining 31 patients, but information with regard to hypersensitivity reactions only was given. Eighteen out of 76 patients (24%) suffered a clinical hypersensitivity reaction; however, no silent inactivation was observed. Activity in the therapeutic range of greater than 100 U/l for at least 14 d was determined in 43 of the 45 patients who were analysed for enzyme activity.