Calcein assay for multidrug resistance reliably predicts therapy response and survival rate in acute myeloid leukaemia

In this study, we evaluated the suitability of the calcein assay as a routine clinical laboratory method for the identification of multidrug-resistant phenotype in acute leukaemia. This study presents the results of the calcein tests obtained in two large haematological centres in Hungary. Assays were performed with blast cells of 93 de novo acute leukaemia patients, including 65 patients with acute myeloid leukaemia (AML). Results were expressed as multidrug resistance activity factor (MAF) values. AML patients were divided into responders and non-responders and MAF values were calculated for each group. In both centres, responder patients displayed significantly lower MAF values than non-responders (P = 0.0045 and P = 0.0454). Cut-off values were established between the MAFR + SEM and MAFNR - SEM values. On the basis of these cut-off levels, multidrug resistance (MDR) negativity showed a 72% predictive value for the response to chemotherapy, whereas MDR positivity was found to have an average predictive value of 69% for therapy failure. MDR activity was a prognostic factor for survival rate and the test was suitable for detecting patients at relapse. The calcein assay can be used as a quantitative, standardized, inexpensive screening test in a routine clinical laboratory setting. The assay detects both P-glycoprotein and multidrug resistance-associated protein activities, and identifies AML patients with unfavourable therapy responses.

Diagnostics of multidrug resistance in cancer

Multidrug resistance (MDR), caused by the overexpression of two membrane proteins, MDR1-Pgp and/or MRP, is a major obstacle in the chemotherapy of cancer. The proper laboratory diagnosis of clinical multidrug resistance is still an unresolved question, and this uncertainty, in a vicious cycle, does not allow the correct evaluation of the clinical relevance of the MDR phenomenon. More-over, inefficient MDR diagnostics hinders the development of effective resistance-modulation strategies. In this review, after describing the basic features of the MDR drug pump proteins, the currently employed diagnostic methods are discussed. We suggest that a quantitative, functional method developed in our laboratory may provide a major help in the laboratory assessment of cancer MDR.

Apolipoprotein E polymorphism in Pick's disease and in Huntington's disease

The polymorphism of apolipoprotein E (apoE) has been recognized as a genetic risk factor in different neurodegenerative disorders, with or without tau protein- related neuropathology, but few published epidemiological data are available as concerns the association of different apoE alleles with two relatively rare forms of dementia, Pick's disease (PiD) and Huntington's disease (HD). In this study the frequency of the apoE4 allele was examined in 36 persons with histopathologically proven PiD and compared with that of the apoE genotype in 28 HD probands and 79 aged healthy controls. The E4 allele was overrepresented selectively in PiD (42%) as compared with the control population (7%). No such association was found for HD probands (9%). This finding lends further support to the hypothesis that the E4 genotype is not an Alzheimer's disease specific susceptibility factor, and that it could be present in diverse dementing disorders with tau protein related neuropathology, such as PiD.

Remarkably reduced transplant-related complications by dibromomannitol non-myeloablative conditioning before allogeneic bone marrow transplantation in chronic myeloid leukemia

A non-myeloablative conditioning protocol containing dibromomannitol (DBM/cytosine arabinoside/cyclophosphamide) has been applied to 36 chronic myeloid leukemia (CML) patients followed by bone marrow transplantation (BMT) from sibling donors. Risk factors include: accelerated phase (10 patients), older age (17 patients over >40 years) and long interval between diagnosis and BMT (27 months on average). Severe mucositis did not occur. Venoocclusive liver disease was absent. Infectious complications were rare. Although grade II-IV acute graft-versus-host disease (GVHD) was present in 9 (25%) cases, there were only 2 serious (III-IV) ones. Chronic GVHD occurred in 25 (69%) cases, preceded by acute GVHD in 9 of the 25 affected patients. Early hematological relapse, 7-29 weeks after BMT, developed in 6 patients (17.6%). No relapse was noted in the completely chimeric patients, however molecular genetic residual disease was observed in 6 patients, in most of them after transient short-term mixed chimeric state. Overall actual survival rate is 83.3% for the 36 cases, and leukemia-free survival is 72.2% for the 34 engrafted patients.

UVB irradiation-induced apoptosis increased in lymphocytes of Huntington's disease patients

Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by CAG repeat expansion in the IT-15 gene coding for huntingtin. The mechanism of neuronal degeneration induced by the mutant huntingtin is not known. Apoptosis may play a role in it. Huntingtin is widely expressed in the cells, so abnormalities can be expected also in non-neural tissue. We examined the susceptibility of lymphocytes from HD patients, asymptomatic carriers and normal individuals to UVB irradiation-induced apoptosis. Lymphocytes from eight HD patients and two asymptomatic carriers showed increased apoptotic cell death compared to controls. Our results suggests that sensitivity of HD cells to induced apoptosis is not restricted to neurons.

Analysis of CAG repeat expansion in Huntington's disease gene (IT 15) in a Hungarian population

Huntington's disease (HD) is a neurodegenerative disorder with autosomal dominant inheritance. The genetic defect is a CAG trinucleotide repeat expansion at the 5' end of the IT 15 gene on chromosome 4. This gene has not been analyzed in the Hungarian population yet. To obtain data DNA from 26 HD patients, 18 members of their families and 70 normal controls was amplified in the involved region by polymerase chain reaction. The CAG repeat numbers varied from 37 to 70 (median: 43) in HD patients and asymptomatic carriers, while individuals of the normal control group had 10-36 CAG repeat numbers (median: 18). The length of CAG repeat expansion in Hungarian HD patients was similar to that reported from other countries. The group of normal controls had the same CAG repeat expansion as populations reported from Western European countries. It is a useful piece of data for population genetics to prove that the population of Hungary is a mélange of different nations that influenced the history of the country in the last 11 centuries. As opposed to this, the only closely related nation, the Finnish, was genetically more isolated during this time, so the frequency of HD (and also the number of CAG repeats in normal individuals) proved to be exceptionally low.

Lymphocyte subset reconstitution after allogeneic bone marrow transplantation using radiation-free conditioning regimen for patients with chronic granulocytic leukemia

Conditioning regimens for BMT are important in determining transplant outcome. A radiation-free protocol containing Mitobronitol (DBM), Cytarabine (Ara-C) and Cyclophosphamide (Cy) was used for conditioning of patients with chronic granulocytic leukemia (CGL). Using this conditioning treatment, fewer transplant related complications, including acute GVHD, VOD and severe infections, were observed. Acute GVHD did not develop, but chronic GVHD, accompanied with graft-versus leukemia, was present in half of the cases. To determine the clinical effect of the DBM/Ara-C/Cy conditioning, the recovery of peripheral blood lymphocytes was examined after allogeneic BMT for patients with CGL in comparison with TBI/Cy conditioning. The lymphocyte subsets of 11 DBM patients were followed and analyzed periodically (30-90 days, 4-12 months and > 13 months) using ten monoclonal antibodies and flow cytometry. Decreased percentage of total T cells as well as CD4+ and CD8+ subpopulations, significantly decreased T cell activation and increased proportion of TCR gamma delta + cells were found to be characteristic in the early post-transplant period in the DBM group. Early recovery and consistently higher percentage of B cells were observed for the whole follow-up period of patients receiving DBM conditioning. A high proportion of NK cells was observed in all transplant recipients. These findings suggest that the characteristic pattern of recovering lymphocytes is associated with the lack of severe transplant-related clinical complications following DBM/Ara-C/Cy conditioning.

Responses to single-dose thrombopoietin decrease with higher platelet counts in mice

Since the description of human thrombopoietin (TPO) we investigated the thrombocytosis-inducing capacity of human serum samples derived from individuals with altered thrombocytopoiesis. Several times the degree of thrombocytosis developing in recipient mice differed markedly even when applying the same human material. In the last 2 years, we applied single doses of recombinant human TPO (rHuTPO) to random-bred CFLP mice, and the same observation was made. Taken together with previous information (before 1970) it was possible to select cases in which the percent increases in circulating platelet counts inversely correlated with the starting levels. It appears, however, that apart from the known absorbing role of platelets and megakaryocytes, the response to single doses of exogenous rHuTPO in mice depends, at least partially, on an unknown endogenous homeostatic mechanism. Mixing thrombopoietically active human sera with platelet-free normal serum in a 1:1 ratio remarkably reduced the thrombocytosis-inducing capacity. Repeated pharmacological doses of TPO, applied in the majority of the reported trials, however, easily obscure the physiological control mechanism.

Parallel functional and immunological detection of human multidrug resistance proteins, P-glycoprotein and MRP1

The proper assessment of the expression and drug extrusion activity of multidrug resistance proteins in various tumor cells is a challenging clinical laboratory problem. Recently, we have introduced a fluorescent dye (calcein) accumulation assay for the estimation of the functional expression of both P-glycoprotein (MDR1) and the multidrug resistance-associated protein (MRP1). Since both MDR1 and MRP1 decrease the intracellular accumulation of the fluorescent free calcein, by applying appropriate inhibitors of MDR1 and MRP1, the transport activity of these proteins could be quantitatively and selectively estimated in fluorometry or flow-cytometry assays. In the present work single-cell fluorescence digital imaging has been applied to characterize the kinetics and inhibitor-sensitivity of calcein accumulation in a mixture of HL60 MRP1 and NIH 3T3 MDR1 cells. Subsequent immunofluorescence labeling was performed by the anti-MDR1 monoclonal antibody (mAb) UIC2 in the same cell population. We report that the double labeling approach, based on the single cell calcein accumulation assay and an immunofluorescence detection, provides good sensitivity and selectivity for the simultaneous functional and immunological detection of cellular MDR1 and MRP1.

Non-supralethal mitobronitol/cytarabine/cyclophosphamide conditioning without irradiation before bone marrow transplantation for accelerated chronic granulocytic leukemia: apparent absence of acute graft-versus-host disease

Cytostatic chemotherapy instead of supralethal total body irradiation (TBI) has been increasingly used as an alternative myeloablative regimen before bone marrow transplantation (BMT). While irreversible azoospermia/amenorrhoea seems to occur less frequently with such conditioning, graft-versus-host disease (GVHD) remains unaffected. Five-year disease-free survival in accelerated chronic granulocytic leukemia (CGL), after BMT with matched sibling grafts has been 0.10-0.30. Mitobronitol, cytosine arabinoside, and cyclophosphamide were used for conditioning. Patients were transplanted with unmanipulated HLA/MLC identical sibling bone marrow. For recovery, a pathogen-low room was available without air filtering and laminar airflow. Seven of eight accelerated-CGL patients were engrafted: full allogeneic reconstitution was detected in four and mixed chimerism in three patients. Five out of the seven engrafted patients survived at least nine months (median = 42 months), two are considered cured (8-9 years survival). The four leukemia-free survivors displayed full allogeneic reconstitution and presented symptoms of chronic GVHD. One patient became a genetically verified father. Acute GVHD and veno-occlusive liver disease (VOLD) were absent in all patients, diffuse interstitial pneumonitis (IP) occurred in one case. Non-supralethal conditioning with mitobronitol/cytarabine/cyclophosphamide in accelerated-CGL allows allogeneic bone marrow reconstitution with survival and cure rates comparable to those achieved with other protocols using TBI or busulphan conditioning. Unlike the latter treatments, however, our protocol leads to fewer transplant-related complications including acute GVHD, IP, VOLD, and azoospermia/amenorrhoea.

[Amphotericin B resistant severe hepato-splenic candidiasis, responding to fluconazole, in a patient following bone marrow transplantation]

A 23 year old woman with Philadelphia-positive chronic granulocytic leukaemia underwent a 3/4 HLA identical bone marrow transplantation. During the neutropenic period, a septic condition developed which was caused by Candida albicans. Administration of Amphotericin B for 63 day was ineffective including an attempt to give the drug through the truncus coeliacus. Finally the sepsis disappeared during fluconazole treatment.

[Survey of one hundred patients with chronic granulocytic leukemia from the view of recent developments]

Data of 100 selected CGL patients were considered. There were 50 male and 50 female patients with an average 38.1 and 41.5 years of age, respectively. Seventy nine patients were in stable, chronic and 21 patients were in accelerated phase. Patients first admitted in blastic phase were excluded. Twenty two patients were subjected to bone marrow transplantation. Characteristically low levels of neutrophil alkaline phosphatase were absent in about 10 to 25% of early cases. It was considered that the level of positive cells could eventually point to the extent of normal population. In the group of the accelerated patients the neutrophil alkaline phosphatase scores were regularly high and the serum cholesterol values lower than those among stable-phase patients. The role of G-CSF (granulocyte colony stimulating factor) was considered. Secondary myelofibrosis was frequently associated with low serum cholesterol. Average survival time was 41 month among non-transplanted and 63+ months among identically-transplanted patients. In accordance with the literature, authors point out that in the presence of any factor not permitting transplantation, prolonged high-dose interferon-therapy could be the first choice, because unlike chemotherapeutic agents used till now, it prolongs survival. Apart from this autotransplantation with marrow or with circulating blood derived stem cells should be considered.

[Role of molecular genetic investigations in the diagnosis of acute leukemias and in the detection of minimal residual disease]

Chimera gene products, the molecular hallmark of acute leukemias were detected and quantified for diagnostic purposes and for follow up of therapy and characterization of minimal residual disease. In acute lymphoid leukemia mainly the bcr-abl, and in acute myeloid leukemias, depending on the morphological classification, the aml-eto, bcr-abl, pml-rara, plzf-rara, and cbfb-myh chimeras were investigated. The determinations were based on reverse transcriptase-polymerase chain reaction. The results were used in diagnosis of 315 new leukemic patients, and in follow up of 70 ones. In the present paper the usefulness of the applied methods is illustrated by presentation of data of 38 (27, acute myeloid leukemias and 11 acute lymphoid ones) patients out of the 139 treated in the National Institute during the last years.

Application of flow cytometry immunophenotyping and multidrug resistance assay in B-cell acute lymphoid leukemia and multiple myeloma

Multidrug resistance is one of the mechanisms how to explain failure of chemotherapy in patients with different hematological malignancies. In this study we aimed to evaluate and compare the drug resistance in B-cell acute lymphoid leukemia (B-ALL) and multiple myeloma (MM) in association with their immunophenotypes and genotypes. Eleven patients with B-ALL and 14 patients with MM were classified according to prognostic factors. Standard MoAb panel for ALL and triple labeled antibodies (CD38/CD56/CD19) and detection of intracellular light chains for MM were used. Flow cytometric calcein assay was performed for measure of P- glycoprotein (MDR-1) and multidrug resistance associated protein (MRP-1) activity. Markers CD19, CD20 and HLA-DR proved to be useful in identifying cells of B-lymphoid lineage. CD34 progenitor cell antigen was present in high proportion of ALL blasts. Both the abnormal plasmacell populations and their monoclonality in MM were confirmed by immunophenotyping, too. The mean MDR activity factor (MAF) values were not different in patients with MM and B- ALL. However, the mean MRP-1 values in MM were significantly lower than MAF-MDR-1 (1.85+/-3.8 versus 5.92+/-7.45, p=0.05), but we have found lower values in refractory conditions as expected from previous studies of acute myeloid leukemia. The immunophenotyping was helpful in detection of abnormal populations showing no correlation with the MDR. However, in this study we could not confirm high MDR activity despite of the failure of chemotherapy. The calcein assay seems to be useful for quantitative and sensitive measurement of the MDR proteins. The low activity of MDR- 1 and MRP-1 in MM need further clarification, indicating the involvement of different transport in the resistance mechanism.

[Immunophenotyping in acute leukemia: detection of minimal residual disease]

Immunophenotyping improves both accuracy and reproducibility of the acute leukaemia classification and is considered particularly useful for identifying poorly differentiated subtypes of acute myeloid leukaemia and lineage association of acute lymphoid leukaemia. Immunological studies of leukaemic blasts has become critical also identifying biphenotypic leukaemias and acute myeloid leukaemia expressing lymphoid associated markers. At present, while the prognostic value of individual antigen expressions is still controversial, the immunologic detection of minimal residual disease seems to be important in monitoring the acute leukaemia patients in remission. In the present study immunophenotyping of bone marrow samples of 42 patients with acute myeloid leukaemia and 13 patients with acute lymphoid leukaemia was analysed. Patients were assessed both before and after treatment by immunophenotyping, cytogenetics and polymerase chain reaction amplification. The immunophenotyping have allowed more sensitive definition of acute leukaemia relapse, but molecular genetic methods are recommended for detection of elimination of residual disease.

[A new radiation-free conditioning in bone marrow transplantation and dibromo-mannitol therapy in chronic myeloid leukemia]

A new, radiation-free, conditioning protocol, containing the original Hungarian mitobronitol (DBM) (DBM/ cytosine arabinoside/cyclosphosphamide) has been applied to 36 chronic myeloid leukemia (CML) patients followed by bone marrow transplantation (BMT) from HLA identical sibling donors between 1990-1997. In spite of some prognostically disadvantageous factors (half of them were above 40 years, 10 out of 36 patients were in accelerated phase, the disease history was longer than 2 years in average) the overall survival (30/36) and the leukemia free survival rate (26/36) were in accordance with the best international results. Transplantation-related toxicity was remarkably reduced in comparison to bone marrow transplantation performed by total body irradiation/cyclophosphamide (TBI/Cy) or busulphan/cyclophosphamide (Bu/Cy) conditioning protocols. Acute graft versus host disease was present in lower percentage (9/36) and the number of serious cases was only 2/36. Chronic GVH disease, generally known to be associated with antileukemic effect (GVL), occurred in 25 of cases. Early haematological relapse among the 34 patients with functioning graft occurred in 6 patients which rate is slightly higher than reported after TBI/Cy or Bu/Cy conditioning treatment. There was no relapse among patients transplanted within one year post-diagnosis and patients having CML with accelerated phase. The leukemia free post-transplant period was in association with the chronic GVH disease and full chimeric state.