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P S Mitrou

Publications and source records attributed to P S Mitrou.

At least 19 recordsLinked to original sources
PubMed2002

Reduced-dose cladribine (2-CdA) plus mitoxantrone is effective in the treatment of mantle-cell and low-grade non-Hodgkin's lymphoma.

Cladribine (2-chlorodeoxyadenosine) (2-CdA) has been shown to be effective in mantle-cell (MCL) and low-grade lymphomas (lgNHL). The aim of this multicentre study was to evaluate the rate and duration of remissions and to examine the toxicity of the combination of reduced-dose 2-CdA and mitoxantrone (CdM) in MCL and lgNHL as first-line therapy or for patients in their relapse. A total of 285 courses, median of five courses per patient, were administered to 62 evaluable patients (42 previously untreated, 20 relapsed) with 5 mg/m(2) 2-CdA per day given as an intermittent 2-h infusion over 3 consecutive days combined with 8 mg/m(2) mitoxantrone on days 1 and 2 for the untreated patients or 12 mg/m(2) mitoxantrone on day 1 for patients in their first relapse for a maximum of six cycles every four weeks. 32 follicular, 18 MCL, 9 lymphoplasmacytoid, 2 marginal zone and 1 unclassified low-grade B-cell lymphoma were involved in the study. 56 of the 62 patients responded to CdM resulting in an overall response rate of 90% (95% confidence interval (CI), 80-96%) with a complete remission (CR) rate of 44% (95% CI, 31-57%) and a median duration of remission of 25 months (range 6-42+). The overall survival rate at 48 months was 80%. For 42 previously untreated patients, the overall response rate was 88% (95% CI, 74-96%) with a CR rate of 38% (95% CI, 24-54%), whereas the response rate for the group of 20 previously treated patients was similar with a 95% overall response (95% CI, 75-100%) and a CR rate of 55% (95% CI, 32-77%). In MCL, CdM showed a high activity, achieving a response rate of 100% (95% CI, 81-100%) with a CR rate of 44% and a median duration of remission of 24 months (range 6-35+). Myelosuppression was the major toxicity with 23% grade 3 granulocytopenia and 50% grade 4. Thrombocytopenia was less commonly observed, with only 8% grades 3 and 4. These results demonstrate that the combination of reduced-dose 2-CdA and mitoxantrone is a highly active regimen in the treatment of low-grade lymphomas, and in particular of MCL.

Adult↗
PubMed2002

Bendamustine is effective in relapsed or refractory aggressive non-Hodgkin's lymphoma.

BACKGROUND: Bendamustine, an alkylating agent with a nitrogen mustard group and a purine-like benzimidazol group, has been shown to be effective in several solid tumors and indolent non-Hodgkin's lymphomas, but has not yet been studied for efficacy in aggressive lymphomas. PATIENTS AND METHODS: We conducted a phase II study in patients with relapsed or refractory high-grade non-Hodgkin's lymphomas, using bendamustine at a dose of 120 mg/m(2) on days 1 and 2, every 3 weeks for up to six cycles. Twenty-one patients were enrolled; 18 were evaluable for response and toxicity, 10 of whom were refractory to previous chemotherapy. RESULTS: With three patients achieving a complete response (at 6, >or=8 and >or=22 months) and five a partial response (three at 2 months, one at 3 months and one at 10 months), the total response rate of the evaluable patients was 44% (eight out of 18; 38% of all patients). Two complete and two partial responders were refractory to prior treatment. In 10 patients, treatment had to be stopped after one to three cycles due to progressive disease or hematological toxicity (n = 2). Non-hematological side effects were mild. Eight (13%) WHO grade 3 and no grade 4 events were observed in 60 evaluable treatment cycles. Hematologic toxicity was moderate (grade 3 and 4): anemia in five cycles (8%), leukopenia in seven (12%) and thrombocytopenia in eight (13%). CONCLUSIONS: Bendamustine as a single agent is effective against aggressive lymphoma, even in cases of refractory disease. Further studies are warranted to determine the significance of bendamustine in the treatment of aggressive lymphomas.

Adult↗
PubMed2001

Deregulated expression of prostate apoptosis response gene-4 in less differentiated lymphocytes and inverse expressional patterns of par-4 and bcl-2 in acute lymphocytic leukemia.

INTRODUCTION: Prostate apoptosis response gene-4, known as par-4, is a new proapoptotic factor functionally required but not sufficient for apoptosis. Since there is evidence from prostate cancer cells that par-4 is involved in regulation of bcl-2 we assessed expression of par-4 and bcl-2 in different populations of normal and neoplastic lymphocytes. MATERIALS AND METHODS: Expression of par-4 mRNA and protein in different subpopulations of normal and neoplastic lymphocytes was assessed by reverse transcription polymerase chain reaction and Western blot. RESULTS: Par-4 mRNA was not detectable in lymphocytes of healthy volunteers (n = 10), but was present in the majority of samples of chronic lymphocytic leukemia (n = 30), chronic lymphocytic leukemia/prolymphocytic leukemia (n = 6) and acute lymphocytic leukemia (n = 10). Par-4 protein was expressed unanimously in samples of mononuclear cells from healthy volunteers and patients with CLL, but less frequently in immature lymphocytes, including neoplastic cells of CLL/PLL and ALL. The decreased frequency of par-4 expression in immature subpopulations was confirmed by results on lymphocytic cell lines at various stages of maturation. Comparing the expressional patterns of par-4 and bcl-2 there was an inverse relationship of both proteins in ALL and different lymphocytic cell lines, indicating a functional relationship of par-4 and bcl-2. CONCLUSIONS: This study establishes par-4 as a factor expressed in the majority of normal and neoplastic lymphocytic cells, demonstrating a decreased frequency of protein expression in less differentiated lymphocytes and an inverse expressional pattern of par-4 and bcl-2 in lymphocytic cell lines and ALL.

Apoptosis Regulatory Proteins↗
PubMed2001

T-large granular lymphocyte leukaemia with natural killer cell-like cytotoxicity and expression of two different alpha- and beta-T-cell receptor chains.

We describe a case of cytotoxic T-large granular lymphocyte leukaemia showing typical morphological features, expressing antigens characteristic for cytotoxic T cells and exhibiting marked natural killer-like cytotoxicity towards different target cells. Moreover, characterization of the T-cell receptors revealed simultaneous expression of two different types of beta-chains as well as alpha-chains by the malignant cell clone. The patient had an 8 year history of indolent disease, before progressing to an aggressive clinical course hardly responsive to chemotherapeutic treatment. This is the first description of a peripheral T-cell neoplasm expressing four distinct types of T-cell receptor molecules.

Disease Progression↗
PubMed2001

Treatment of aggressive, or progressing indolent peripheral T- and NK-cell neoplasias by combination of fludarabine, cyclophosphamide and doxorubicine.

BACKGROUND: Regarding standardization of treatment, classification, and pathophysiology of peripheral T- and NK-cell neoplasias the current knowledge is markedly behind that of B-cell lymphomas, which are approximately 10 times more frequent. In May 2000, the study group 'Peripheral T- and NK-cell Neoplasias' was founded in Frankfurt/M. This group decided on a clinical protocol and a scientific program for research on the pathophysiology of these entities. Rationales for the therapeutic regimen are the efficacy of cyclophosphamide and doxorubicine as shown in protocols for treatment of high grade lymphoma, the synergism of cyclophosphamide and fludarabine, and reports demonstrating the efficacy of fludarabine in T-cell neoplasias. PATIENTS AND METHODS: Patients will be treated with a combination of fludarabine (30 mg/m(2) days 1-3), cyclophosphamide (1000 mg/m(2) day 1) doxorubicine (25 mg/m(2) day 2+3) (FCD). For patients > or =65 years a dose-reduced FCD regimen will be administered. In patients included in the treatment study and additionally in patients with indolent disease not requiring therapy, scientific projects on the biology of peripheral T- and NK-cell neoplasias will be performed. CONCLUSIONS: Expected conclusions of the projected study are the establishment of treatment and diagnostic standards, and improvement of classification of these entities by clinical, morphologic and biologic parameters.

Aged↗
PubMed2001

Changing incidence and survival in patients with aids-related non-Hodgkin's lymphomas in the era of highly active antiretroviral therapy (HAART).

To determine role of highly active antiretroviral therapy (HAART) and additional factors in incidence and outcome of patients with AIDS-related non-Hodgkin's lymphomas (NHL) we retrospectively analyzed 257 cases of AIDS-related NHL (24 low-grade, 168 high-grade B-cell, 6 high-grade T-cell, and 59 primary CNS lymphomas (PCNSL) among 2004 patients with HIV-infection treated at the University Hospital of Frankfurt, Germany from January 1983 to May 1999. Data were evaluated by univariate and multivariate analyses, using overall survival as end point. Patients received CHOP-like therapy as standard treatment. Until May 1999 incidence of all diagnosed cases of NHL was decreasing (1991-94: 14.2% versus 1995-5/99: 12.8%). Mainly, the incidence of low-grade NHL and PCNSL clearly decreased whereas the incidence of high-grade B-cell NHL increased compared to all diagnosed cases of NHL (1983-86: 53.3% versus 1995-5/99: 78.6%). One-year survival probability of all screened patients with AIDS related NHL was 54%, while 5-year survival rate remained 5%. We found age <25 years, development of NHL in the years before 1990, IVDU, CD4 counts <150/microl, PCNSL as well as NHL as the AIDS index disease, to be highly significant independent predictors of poor survival, including increased hazard ratios. In the era of HAART incidence of NHL is decreasing, mainly the incidence of low-grade NHL and PCNSL. Overall survival of patients has been prolonged with HAART. This development is mainly due to improvement of antiretroviral therapy, rather than to any fundamental changes in the chemotherapeutic treatment of NHL. Therefore, new treatment approaches for AIDS-related NHL should focus on more efficient antiretroviral therapy in association with combination chemotherapy.

Acquired Immunodeficiency Syndrome↗
PubMed2001

In vitro induction of apoptosis of neoplastic cells in low-grade non-Hodgkin's lymphomas using combinations of established cytotoxic drugs with bendamustine.

BACKGROUND AND OBJECTIVES: Regulation of apoptotic cell death is being increasingly recognized as a mechanisms by which cytostatic agents mediate tumor cell death. Preliminary clinical studies with bendamustine, an alkylating agent with a purine nucleus, provide strong evidence that this drug is a highly effective cytostatic in low grade lymphomas. Therefore, we investigated the in vitro activity of bendamustine in combination with other established cytotoxic drugs. DESIGN AND METHODS: 2 lines (DOHH-2, WSU-NHL) and mononuclear cells (MNC) from patients with leukemic low-grade B-non-Hodgkin's lymphoma (NHL) (n=10), T-NHL (n=7) and chronic lymphocytic leukemia (CLL) (n=12). Apoptosis (7-AAD), depolarization of mitochondrial membrane potential (MMP, JC-1), caspase-3-activity (FIENA) and cell proliferation (XTT/WST-1) were determined. Several incubation times and drug dosages (for IC(30/50/75/90)) were studied. Synergistic, additive or antagonistic effects were calculated by a median plot effect and the combination index (CI) method. RESULTS: In general, combinations of bendamustine with mitoxantrone or doxorubicin resulted in antagonistic effects in the tested cell lines and the MNC from the patients. CI-calculation failed in these cases since there was not a sufficient dose response. On the other hand, the combination of bendamustine with 2-CdA showed synergistic in vitro activity on the tested cell lines, neoplastic lymphocytes from patients with peripheral T-cell lymphomas and partially on MNC from patients with CLL and B-NHL. The antagonism of the combination of bendamustine and anthracyclines appeared to be due to inhibition of depolarization of mitochondrial-membrane potential and caspase-3-activity during apoptosis of the studied cell lines. INTERPRETATION AND CONCLUSIONS: In conclusion, our results suggest that schedules using combinations of bendamustine and anthracyclines should not be recommended for the treatment of low-grade NHL, whereas bendamustine combined with 2-CdA could be considered for the development of future treatment strategies.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Induction of apoptosis using 2',2' difluorodeoxycytidine (gemcitabine) in combination with antimetabolites or anthracyclines on malignant lymphatic and myeloid cells. Antagonism or synergism depends on incubation schedule and origin of neoplastic cells.

Induction of apoptosis in vitro using gemcitabine (dFdC) in combination with cladribine (2-CdA) and other cytotoxic drugs on malignant mononuclear cells (MNCs) of patients with acute myeloid leukemia (AML, n=20) and chronic lymphocytic leukemia (CLL, n =20) in myeloid (HL60, HEL) and lymphatic cell lines (HUT78, JURKAT) was investigated using different incubation conditions (simultaneous and consecutive). Furthermore, the influence of dFdC on the level of intracellular metabolites of 2-CdA was studied using high-performance liquid chromatography (HPLC). Apoptosis was evaluated using flow cytometry with 7-aminoactinomycin D. In MNCs of patients with CLL, dFdC + 2-CdA showed an antagonistic effect when applied simultaneously. This antagonism was reduced by consecutive application. The combination of dFdC with doxorubicin was synergistic, independent of incubation schedule. In blasts from newly diagnosed patients with de novo AML, all drug combinations (dFdC+2-CdA, doxorubicin, or cytosine arabinoside) were antagonistic by simultaneous incubation. Reduced antagonism or even synergism was shown (P<0.001) by consecutive incubation. The simultaneous combination of dFdC with 2-CdA in all tested cell lines resulted in a competitive inhibition on the rate of apoptosis. By changing the incubation period to a consecutive schedule, the antagonism was diminished or synergism of apoptosis was measured (P< 0.001). Using similar incubation conditions, these experiments were supported by HPLC measurement of intracellular metabolites of 2-CdA influenced by dFdC application. In conclusion, we demonstrated that the efficacy of dFdC in vitro in combination with other cytotoxic drugs depends on the incubation condition and on the origin of neoplastic cells (lymphatic vs myeloid). The data suggest that simultaneous combination therapy with purine and pyrimidine analogues may not improve the clinical efficacy of one or the other drug administered alone.

Anthracyclines↗
PubMed2000

Effect of treatment with amifostine used as a single agent in patients with refractory anemia on clinical outcome and serum tumor necrosis factor alpha levels.

Amifostine increases in vitro burst-forming unit-erythroid and colony-forming unit-granulocyte/granulcoyte-macrophage cultured from bone-marrow cells from patients with myelodysplastic syndrome (MDS). Several small clinical studies give divergent informations about the potential of amifostine as single agent to improve hematopoiesis in MDS patients. In these studies, patients with refractory anemia (RA), RA with excess of blasts (RAEB), and RAEB in transformation (RAEB-T) were analyzed together, resulting in response rates varying from 8% to 30%. The present multi-center study evaluated whether treatment with amifostine is of clinical benefit in patients with RA who are transfusion dependent. The effect on transfusion frequency as well as on platelets and absolute neutrophil count (ANC) was examined in 14 patients with RA [median age 67 years (55-72 years), male:female 9:5]. Four treatment cycles were planned, each consisting of intravenous amifostine at 200 mg/m2/day three times per week followed by a 2-week interval. Since tumor necrosis factor (TNF) alpha is a main suppressive cytokine for hematopoiesis in RA patients, serum samples for analyzing endogenous levels of TNF alpha were collected prior to the study and after four treatment cycles. In three patients (21%), reduced transfusion requirement with prolongation of the transfusion interval from 4 weeks to 8 weeks (two patients) and 4 weeks to 6 weeks was seen. An increase in ANC from 400/microliter to 2600/microliter and 200/microliter to 3400/microliter was observed in two patients. Platelets increased from 129,000/microliter to 277,000/microliter in an additional patient. In one patient, disease progression from RA to RAEB was observed. Serum TNF alpha levels were increased in MDS patients compared with normal controls (18.8 pg/ml vs 9.1 pg/ml), and there was no change during the treatment with amifostine (17.5 pg/ml). In conclusion, treatment with amifostine as a single agent was of limited benefit in patients with RA. The serum TNF alpha levels were unchanged during treatment with amifostine in RA patients.

Aged↗
PubMed2000

Induction of apoptosis by 2-chloro-2'deoxyadenosine (2-CdA) alone and in combination with other cytotoxic drugs: synergistic effects on normal and neoplastic lymphocytes by addition of doxorubicin and mitoxantrone.

2-CdA is active as a single agent in the treatment of low-grade lymphomas. We analyzed the induction of apoptosis by 2-CdA alone (n=5) and in combination with other drugs in peripheral lymphocytes from 25 patients with leukemic low-grade lymphomas and from 25 healthy volunteers. 2-CdA was tested in 4 escalating concentrations (0.05 microg/ml to 0.4 microg/ml). Linear regressions showed a dose dependent apoptosis rate of 0.29 x microg 2-CdA/ml + 0.11 (r2=0.88, p=0.006) in normal cells and 0.41 x microg 2-CdA/ml + 0.15 (r2=0.88, p=0.005) in leukemic cells. Intracellular metabolization of 2-CdA into 2-CdA-5'mono-, -di- and the active metabolite -triphosphate was analyzed by HPLC and paralleled the dose dependent increase of apoptosis. The combination of 2-CdA with doxorubicin or mitoxantrone had a synergistic effect on the induction of apoptosis (p<0.001) in both normal and neoplastic lymphocytes, whereas 2-CdA plus etoposide or cytosine arabinoside were only additive. Due to the flat slope of the dose response of 2-CdA concentration on apoptosis we assume that higher in vivo dosages of 2-CdA in the treatment of low-grade lymphomas may not result in a higher clinical efficacy. The synergistic lymphocytotoxic effect of 2-CdA combined with doxorubicin or mitoxantrone may be relevant for new treatment approaches.

2-Chloroadenosine↗
PubMed2000

Cytotoxic hepatosplenic gammadelta T-cell lymphoma following acute myeloid leukemia bearing two distinct gamma chains of the T-cell receptor. Biologic and clinical features.

BACKGROUND AND OBJECTIVES: Hepatosplenic gd T-cell lymphoma is a rare entity of peripheral T-cell lymphomas. We characterized in detail the first case of hepatosplenic gd -T-cell lymphoma following acute myeloid leukemia. DESIGN AND METHODS: Hepatosplenic gd -T-cell lymphoma was diagnosed in a woman who had been in complete remission (CR) of acute myeloid leukemia (AML) for two years. Improvement but no objective response of the disease was observed after various types of chemotherapy. CR was achieved after related donor stem cell transplantation. Thirteen months later relapse of hepatosplenic gd T-cell lymphoma was diagnosed. While being prepared for a second transplantation the patient developed meningeal lymphoma and died. The patient's lymphoma cells were studied by immunologic, functional and molecular techniques. RESULTS: Lymphoma cells expressed the gd T-cell receptor (TCR), CD2, CD3, CD5, CD7, CD38, CD45, CD161 (NKR-P1), TIA and Ki67. Further analysis revealed expression of Vd1 and two distinct TCRg chains, Vg3 and Vg9, by the malignant cell clone. The clonality of the T-cells was confirmed by reverse transcriptase polymerase chain reaction (RT-PCR) followed by sequencing of TCR Vg3, Vg9 and Vd1 junctional regions. Clone-specific PCR was negative at diagnosis of AML and was positive at all times during follow-up of the hepatosplenic gd T-cell lymphoma. The lymphoma cells mediated strong natural killer cell-like cytotoxic activity, possibly explained by expression of CD161 and a lack of killer inhibitory receptor. INTERPRETATION AND CONCLUSIONS: Several so far undescribed features were observed in this case of hepatosplenic gd T-cell lymphoma, such as T-cell lymphoma following AML, expression of two distinct T-cell receptor g-chains, and an unexpected cytotoxic phenotype.

Acute Disease↗
PubMed1999

Fludarabine and epirubicin in the treatment of chronic lymphocytic leukaemia: a German multicenter phase II study.

PURPOSE: Fludarabine has been reported to be the most effective single-agent in previously treated chronic lymphocytic leukaemia (CLL). Based on the in vitro synergism of fludarabine with anthracyclines and on results showing a higher efficacy of CHOP against COP we attempted to improve treatment results with a combination of fludarabine and an anthracycline. PATIENTS AND METHODS: The aim of the multicenter study was to evaluate the rate and duration of remissions and investigate the toxic and immunosuppressive effects of fludarabine and epirubicin in the treatment of CLL in Binet stages B and C as first-line therapy or in first relapse. Thirty-eight patients were treated with fludarabine 25 mg/m2 on days 1-5 and epirubicin 25 mg/m2 on days 4 and 5. RESULTS: The overall response rate (OR) was 82% (95% confidence interval (95% CI): 66%-92%) with a CR rate of 32% (95% CI: 18%-49%). For the 25 previously untreated patients the OR was 92% (95% CI: 74%-99%) including 40% CRs (95% CI: 21%-61%). Granulocytopenia grade 3 occurred in 23% of all evaluable cycles, and grade 4 in 17%. The median remission duration was 19 months (range 6-37 months). CONCLUSION: The results show that the combination of fludarabine and epirubicin is tolerable and highly effective in the treatment of CLL. With the addition of epirubicin to fludarabine, it appears possible to achieve a higher response rate and a more rapid response, especially of nodal manifestations. This regimen can be administered in an outpatient facility except for the first cycle because of the risk of a tumour lysis. The possible benefit of the combination presented here in the treatment of CLL in comparison to single-agent fludarabine treatment is presently under study in a prospective randomized multicenter study.

Adult↗
PubMed1999

Treatment of mantle-cell lymphomas with intermittent two-hour infusion of cladribine as first-line therapy or in first relapse.

PURPOSE: Cladribine (2-chlorodeoxyadenosine, 2-CdA) has been reported to be effective in the treatment of low-grade lymphomas. The objective of this multicenter study was to evaluate the activity of cladribine in mantle-cell lymphomas as first-line therapy or in first relapse using an intermittent two-hour infusion of cladribine. PATIENTS AND METHODS: A total of 47 courses, or an average of four courses per patient, were administered to 12 patients (seven untreated, five relapsed) with 5 mg/m2 cladribine given as an intermittent two-hour infusion over five consecutive days for a maximum of six cycles every four weeks. RESULTS: Cladribine showed activity in patients with mantle-cell lymphomas, achieving a response rate of 58% (95% confidence interval (95% CI): 28%-85%). Myelosuppression was the major toxicity with 17% of grade 3 and 4 neutropenia. Thrombocytopenia was rare with only 2% of grade 3 and 4. CONCLUSION: These results demonstrate single-agent activity of cladribine in mantle-cell lymphomas using the intermittent two-hour infusion dosage regimen. To further improve treatment results, cladribine should be combined with other agents active in mantle-cell lymphomas.

Aged↗
PubMed1999

Positron emission tomography (PET) for staging and evaluation of response to treatment in patients with Hodgkin's disease.

Forty two examinations utilizing F-18 FDG-PET were performed in 23 patients with Hodgkin's disease to study for involved lymphoma regions and compared to conventional staging procedures. Twenty stagings were performed at diagnosis of untreated Hodgkin's disease or at first relapse, and 22 restagings during and after chemoradiotherapy. At diagnosis in 5 of 20 patients PET and other procedures revealed different extranodal manifestations and in 3 patients established different clinical staging. PET seemed to be accurate in the assessment of lymphoma involvement in nodal sites. During follow up, in 10 out of 22 investigations different results and discrepancy were recorded, mostly due to the different extent of F-18-FDG metabolism in residual masses in lymphatic tissues compared to CT, X-ray or ultrasonography. The results indicate that PET may have advantages in the assessment of remissions in nodal sites. Less conclusive results were observed with regard to extranodal involvement or inflammatory disease. In conclusion PET may be sufficient for the staging of the majority of patients with Hodgkin's disease and particularly for assessing remission status in nodal sites, but PET may have disadvantages in the evaluation of extranodal lymphoma and inflammatory disease.

Adolescent↗
PubMed1999

Intermittent 2-hour-infusion of cladribine as first-line therapy or in first relapse of progressive advanced low-grade and mantle cell lymphomas.

Aim of this multicenter-study was to evaluate rate and duration of remissions and to examine toxicity of cladribine in low-grade lymphomas as first-line therapy or in first relapse using intermittent 2-hour-infusion of cladribine. A total of 294 courses, median of 5 courses per patient, were administered to 66 evaluable patients (53 previously untreated, 13 relapsed) with 5 mg/m2 cladribine given as intermittent 2-hour-infusion over 5 consecutive days for a maximum of 6 cycles every four weeks. Entities: 26 follicle center, 20 lymphoplasmacytoid, 12 mantle cell, 6 T-cell, 2 marginal zone lymphomas. Fifty of 66 patients responded to cladribine corresponding to an overall response rate of 76% (95% confidence interval (95% CI): 64%-85%) with 38% CR (95% CI: 26%-51%) and a median time of remission duration of 23 months (range 6-45+). The overall survival rate at 48 months was 72%. For 49 previously untreated patients with B-cell lymphomas the overall response rate was 86% (95% CI: 73%-94%) with a high CR rate of 43% (95% CI: 29%-58%). Response rate for the group of 23 previously untreated patients with follicle center lymphomas was high with 96% overall response (95% CI: 78%-100%) and 57% CR rate (95% CI: 34%-77%). Cladribine also showed activity in patients with mantle cell lymphomas achieving a response rate of 58% (95% CI: 28%-85%). Myelosuppression was the major toxicity with 17% neutropenia grade 3 and 4. Thrombocytopenia was rare with only 2% grade 3 and 4. A prolonged CD4-lymphocytopenia was observed in all patients. Life threatening complications were not observed. These results confirm the major single-agent activity of cladribine in a large cohort of patients with untreated low-grade lymphomas using the intermittent 2-hour-infusion dosage-regimen. To improve treatment results furthermore, cladribine should be combined with other agents active in low-grade lymphomas.

Adult↗
PubMed1997

Establishment and characterization of a new, factor-independent acute myeloid leukemia line designated Ei501.

We established a factor-independent acute myeloid leukemia cell line, designated Ei501. The line has been growing in RPMI 1640 media for 18 months and can be maintained without addition of growth factors. Ei501 is positive for myeloperoxidase and negative for esterase and PAS. Cytogenetic analysis revealed the FAB M3 associated t(15;17) translocation and a translocation of the chromosomes 7 and 8: 46 XX, -7, +t(7;8)(q32;q13), t(15;17)(q22;q12). This karyotype was confirmed by fluorescence in situ hybridization. Ei501 cells express AML-associated surface markers such as CD13, CD33 and CD38. Although 42% of the patient's blast cells were CD34-positive, the line lacks surface expression of CD34. Furthermore the line has a number of characteristics which are detectable in blasts from AML patients, such as surface adhesion molecules, cytokines such as TGF-beta, cytokine receptors such as the IL-2 receptor beta and gamma chains or the IL-4 receptor and the genes for the transcription factor wt-1 (Wilms' tumor gene) and for the proto-oncogene bcl-2, both shown to be present in the majority of patients with AML. Additionally the line can be used as target in cytotoxicity assays using IL-2 activated cytotoxic lymphocytes as effector cells. In conclusion, besides a rare karyotype the Ei501 cell line has several features common in AML, and may therefore be used as a model to study pathogenetic mechanisms in acute myeloid leukemia.

Adolescent↗
PubMed1997

The Wilms' tumor gene is expressed in a subset of CD34+ progenitors and downregulated early in the course of differentiation in vitro.

The Wilms' tumor gene (wt1) is strongly expressed in malignant blasts of acute myeloid leukemia (AML) in approximately 80% of all cases. However, the role of wt1 expression in non malignant hematopoietic cells remains unclear. To characterize the expression of wt1 in differentiating hematopoietic progenitors, we isolated and cultured CD34+ progenitor cells from four healthy bone marrow donors with stem cell factor (SCF) and granulocyte colony stimulating-factor (G-CSF) to induce differentiation into granulocytes. Four different cultures were carried out for 12 days. During culture, wt1 mRNA expression was analyzed by defining its ratio relative to beta-actin using reverse transcriptase polymerase chain reaction (RT-PCR). To monitor the stage of differentiation, expression of cell surface markers and peroxidase was analyzed daily. The initial purity of CD34+ cells ranged between 80% and 90%; after 12 days, the frequency of neutrophil bands and segmented neutrophils was approximately 60%. Using RT-PCR to determine the ratio of wt1 to beta-actin expression, we reproducibly detected maximum expression of wt1 mRNA at day 0 in two cultures and at day 1 in two other CD34+ cell cultures; at both these time points nearly all cells fulfilled the morphological and immunephenotypical criteria of early hematopoietic blast cells. Wt1 expression dropped rapidly at day 1 and 2, respectively, in these two pairs of cultures, and was accompanied by an increase of cells expressing CD33 surface antigen. Our data suggest that wt1 expression is restricted to a subset of CD34+ progenitors and downregulated in later stages of differentiation in vitro.

Antigens, CD34↗