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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new cell line derived from a spontaneous canine leukemia was established and designated GL-1. The cells have been cultured in a floating fashion and passaged for over two years. They were round with rich cytoplasm containing many rough endoplasmic reticula and mitochondria. Peroxidase staining was negative. The nuclei of many cells were round, but segmented nuclei were seen frequently. The doubling time of the cells was 27.3 hr and they had 78 chromosomes. Surface marker analysis using monoclonal antibodies (MABs) and flowcytometry revealed that GL-1 possessed CD45 and surface IgG. However, the cells did not react with MABs detecting T-cell markers. These results indicate that GL-1 has a lymphocytic lineage and is derived from a B-cell leukemia.
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PMID:Establishment and characterization of a new canine B-cell leukemia cell line. 874 12

Laboratory directors who routinely utilize flow cytometry for at least part of their diagnostic evaluations in leukemias or lymphomas were surveyed by mail. The survey consisted of 12 questions about the flow cytometry procedures used by the laboratory in evaluating leukemias and lymphomas and on the format and content of their official report. It also requested an example of a typical leukemia/lymphoma report and solicited write-in comments about additional important aspects of using flow cytometry to evaluate leukemia and lymphomas not covered by the questionnaire. The goal of the survey, which was sponsored by the Clinical Cytometry Society (CCS), was to document what directors of flow cytometry laboratories currently consider to be the appropriate contents of a clinical leukemia/lymphoma phenotyping analysis and in what manner and detail they report such flow cytometry results to clinicians. The survey indicated that a large number of markers are routinely evaluated to phenotype leukemias (mean = 19) and lymphomas (mean = 16). Light scatter gating, using CD45/14 to monitor the gate selected, is currently employed by a 2:1 ratio over the next most population gating strategy (CD45 vs. 90 degrees LS). Peripheral blood, bone marrow, and lymphoid tissue constitute the majority of clinical specimens evaluated for leukemia and/or lymphoma. Two-color analysis, primarily for surface markers, is currently the standard method for flow cytometry measurements in routine diagnostic studies of leukemia and lymphoma. The official flow cytometry laboratory report is most commonly an individual-lab-generated, paper report form. A discussion of the potential benefits that might result from the development of improved computerized reporting software and from the increased use of antibody-defined, lineage gating is offered. A composite report format is presented that demonstrates the flow measurements and quality control data included in the best of the example clinical reports submitted as part of the survey and considered important by a majority of our survey respondents. The example report is intended to be a basis for further discussion within the flow cytometry community on whether minimum reporting standards for leukemia and/or lymphoma flow cytometry results can and should be developed.
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PMID:Laboratory practices in reporting flow cytometry phenotyping results for leukemia/lymphoma specimens: results of a survey. 874 77

Apoptosis plays a critical role during T cell development, both in the generation of functionally competent T cells in the thymus and the regulation of peripheral T cell populations. The fate of any T cell, whether it is developing in the thymus, or functioning in the peripheral immune system, is dependent on T cell receptor (TCR) specificity for antigens presented by MHC molecules and on the consequences of TCR-generated intracellular signalling pathways which lead to activation, anergy or apoptosis. This review describes data that have elucidated the way in which these highly regulated TCR-derived signalling pathways lead to such diverse final outcomes in thymocytes. Contributions to the induction of apoptosis in thymocytes by signalling pathways and receptors such as Fas, CD45 and CD28 are summarized, particularly with regard to the analysis of relevant transgenic mice. Developments concerning regulation of apoptosis by bcl-2 family members and the possible effectors of apoptosis, proteases, are assessed. Finally, this information is contrasted with the relatively scarce data on signalling pathways in thymic-derived T-ALL cells together with potential explanations of how transformation might occur by perturbation of apoptotic mechanisms. Precise understanding of these pathways may lead to the development of novel therapeutic reagents.
Leukemia 1996 Sep
PMID:The role of intracellular signalling pathways regulating thymocyte and leukemic T cell apoptosis. 875 58

Flow cytometry is a powerful tool for immunophenotyping of acute leukemia. Gating of leukemic cells is currently performed on the two dimensional display of forward scatter (FSC) and side scatter (SSC). However, this gating method can not discriminate leukemic cells from contaminated normal cells. Therefore, we used a CD45 monoclonal antibody to detect leukemic cells (CD45dlm cells) in combination with the SSC parameter. This CD45-SSC gating method was very useful for immunotyping of AML and ALL, especially leukemia with a low percentage of blasts. We recommend this new gating method for more accurate immunophenotyping of acute leukemia.
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PMID:[CD45 gating of acute leukemia]. 875 33

Hairy-cell leukaemia may be difficult to diagnose in bone marrow biopsies, especially in the early stages or in its residum after complete clinical remission. To consider the impact of published data on immunophenotyping hairy-cell leukaemias, a total of 50 diagnostic biopsies were systematically analysed with a panel of eight antibodies and compared with cases of chronic lymphatic leukaemia (CLL), 20 follicular centre lymphomas, 20 lympho-plasmacytoid immunocytomas, 10 small-cell T-cell non-Hodgkin lymphomas and 20 cases of benign nodular lymphatic hyperplasia. The panel of eight antibodies comprised DBA44, CD45, CD20, CD45R, CD45RO, CD43 and the CD68 antibodies KP1 and Ki-M1P. The hairy-cell leukaemias were staged histologically into four categories of bone marrow infiltration. DBA44 reacted positively in 47/50 cases. CD45 and the B-cell markers CD20 and CD45R reacted in 49/50 and 43/50 cases, respectively. One CD68 marker, KP1, was positive in 38/50 cases but the other-Ki-M1P-only in 1/50 cases. Chronic lymphatic leukaemia cases, the other B-cell NHLs and lymphatic hyperplasias showed strong positivity for CD20 and CD45R, but only the immunocytomas reacted with DBA44 in 7/20 cases. The T-cell NHLs and hyperplasias showed a strong positivity for the T-cell markers CD45RO and CD43. The CD68-marker Ki-M1P revealed a high specificity since it was negative in all NHLs and positive only in one hairy-cell leukaemia. Methyl-methacrylate embedding of bone marrow biopsies under cold polymerization produces a high quality of histo- and cytomorphology, resulting in greater diagnostic reliability and the detection of low-stage infiltration of hairy-cell leukaemia. DBA44 appears as a highly specific antibody to mark hairy-cells since only immunocytomas reacted positively in a few cases. A small panel of antibodies including DBA44. CD20, CD45R and Ki-M1P may serve to distinguish small-cell. NHL from hairy-cell leukaemia even at an early stage or when there are minimal residual tumour cells.
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PMID:Immunophenotype of hairy-cell leukaemia after cold polymerization of methyl-methacrylate embeddings from 50 diagnostic bone marrow biopsies. 906 39

Clinical specimens of blood, bone marrow, lymph node, extranodal tissue, and body fluid were collected from 67 cases of hematologic neoplasms (including chronic lymphoid leukemias, T- and B-cell lymphomas, and acute lymphoblastic and myelogenous leukemias) for comparison between the right-angle light scatter (RALS)/CD45 and the forward-angle light scatter (FALS)/RALS gating combinations. One to three diagnostic markers were selected from each case, yielding 124 paired results for comparison. We found that the percentage of tumor cell isolation and the total cell count in the tumor cell gate were higher in RALS/CD45 than in FALS/RALS. When 20% was used as a cutoff point, 30 markers in FALS/RALS failed to identify the tumor population, while only 3 markers in RALS/CD45 failed to do so. The discriminative factor in the RALS/CD45 gating was mainly the CD45 intensity, whereas all cases except 3 showed low RALS. Although T-cell neoplasms showed a higher proportion of high CD45 intensity, other groups shared similar ranges of CD45 intensity, which is therefore of limited value for differential diagnosis. The RALS/CD45 combination produces higher recovery and purity for tumor cell isolation than the FALS/RALS combination and should replace the latter for routine immunophenotyping of lymphoma and leukemia.
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PMID:Gating strategy for immunophenotyping of leukemia and lymphoma. 926 Jul 55

The classification of natural killer (NK)-cell and NK-like T-cell malignancies has undergone significant evolution in recent years. Although examples of NK-cell tumors resembling acute leukemia have been described anecdotally as blastic, blastoid, or monomorphic NK-cell leukemia/lymphoma (NKL/L), the clinical and pathologic features of these tumors have not been systematically defined. We report four patients with blastic NKL/L and describe the clinical, pathologic, and immunophenotypic findings in these cases. All patients were elderly (58-82 years) and presented with cutaneous plaques. Two patients also had adenopathy, and three patients had marrow involvement at presentation. Biopsy of cutaneous lesions showed atypical superficial and deep dermal lymphoid infiltrates. Involved lymph nodes were architecturally effaced by an interfollicular infiltrate with blastic cytologic features. In Wright-Giemsa-stained blood or marrow smears, tumor cells had finely distributed nuclear chromatin, many with nucleoli, and variable amounts of cytoplasm. In contrast to many NK and NK-like T-cell disorders, azurophilic cytoplasmic granules were absent or inconspicuous. The tumor cells were immunophenotypically distinctive. They expressed intermediate density CD45, as is characteristic of blasts; in addition, the cells were positive for HLA-DR, CD2, CD4, and the NK-associated antigen CD56. Surface CD3, cytoplasmic CD3, and CD5 were negative in all cases tested, whereas CD7 was expressed in two cases. In formalin-fixed tissue, tumor cells marked with antibodies to CD43, but not with other T- or B-lineage-related antibodies. All three cases studied for Epstein-Barr viral RNA by in situ hybridization were negative. Although treatments varied, all three patients with clinical follow-up died within months of the diagnosis. The clinical course in two patients culminated in an overtly leukemic phase. These findings suggest that blastic NKL/L represents a distinct clinicopathologic entity, characterized by cutaneous, nodal, and marrow involvement by blastic cells with immunophenotypic characteristics of true NK cells. The disease afflicts elderly patients, pursues an aggressive course, and may culminate in overt leukemia.
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PMID:Blastic natural killer cell leukemia/lymphoma: a clinicopathologic study. 1043 71

A case of central nervous system (CNS) leukemia with normal bone marrow, associated with a novel chromosomal abnormality, is described. A 58 year-old woman complained of hearing disturbance, severe headache and vomiting, and showed signs of meningeal irritation, as well as papilledema and bilateral dysacusis. Immature atypical cells were found in the cerebrospinal fluid (CSF) with elevated pressure, pleocytosis, increased protein and decreased glucose levels. She was diagnosed as having neoplastic meningitis. In spite of intensive investigations, including bone marrow puncture, malignancies were not found in organs other than intra-cranial site. The symptoms and CSF findings were temporarily improved with chemotherapy and irradiation, but she relapsed into neoplastic meningitis. The anaplastic cells in CSF were positive with CD45 by immunocytochemistry, and were positive by peroxidase staining. Thus, the anaplastic cells were considered to be myelocytic leukemic cells. Chromosomal analysis showed that these leukemic cells had a novel chromosomal abnormality: 46XX, 4q+, 10q-, 16q-. There has been no report of leukemic meningitis without bone marrow abnormalities. It is possible that this peculiar abnormal chromosome is related to the primary infiltration of the central nervous system. With this novel chromosomal abnormality, this case is important for considering the mechanism of primary leukemic meningitis.
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PMID:Primary central nervous system leukemia with a novel chromosomal translocation. 933 20

A flow cytometry method has been introduced into the routine investigation of whole bone marrow samples following red blood cell lysis on the basis of a primary CD45/side scatter (SSC) gating procedure. Blast cells were first identified by CD45/SSC gating in 74 cases of acute myeloid leukemia (AML) and the results were compared to a conventional FSC/SSC gating procedure and to MGG-staining smears. The percentages of blast cells in these samples as defined by the morphological analysis of MGG smears correlated better with the values determined by CD45/SSC gating (r = 0.94) than with the blast cell counts recorded with FSC/SSC gating (r = 0.76). These findings were not surprising because while CD45 expression was regularly lower on leukemic blasts than on normal lymphoid and monocytic cells, the FCS/SSC characteristics of these populations were overlapping. In 53 samples, the blast cell populations were also analyzed with a panel of FITC-conjugated monoclonal antibodies that were utilized in double labeling with CD45-PE. We show that the CD45/SSC gating procedure improved phenotypic determination of the blast cells in three ways: (1) by discriminating between leukemic blast cells and residual normal cells; (2) by excluding normal cells from the phenotypic analysis of leukemic blast cells; and (3) by identifying blast cell heterogeneity in many cases of leukemia on the basis of different CD45 display. Moreover, this immunophenotyping procedure on whole bone marrow samples also allowed an efficient discrimination between the various cell lineages and facilitated the analysis of leukemic blasts present in low proportions.
Leukemia 1997 Nov
PMID:Flow cytometry CD45 gating for immunophenotyping of acute myeloid leukemia. 936 21

CD45-negative B-cell precursor acute lymphoblastic leukaemia (ALL) provides a unique model to study the stem cell compartment in ALL as leukaemic CD34-positive cells, unlike their normal counterparts, do not express CD45. By increasing the number of events analysed to 10(6), storing only the events in the region of interest (storage gate), using appropriate isotype controls and stringent washing procedures, a flow cytometric protocol was established to characterize rare CD34+ CD19- events. In eight of 12 patients (67%) with CD45-negative B-cell precursor ALL, a distinct CD34+ CD19- CD45+ candidate normal stem cell population could be detected. In one patient analysed by four-colour staining, the CD34+ CD19- CD45+ cells, unlike the CD45-negative leukaemic cells, expressed CD117 (c-kit), providing further evidence that these cells represent residual nonleukaemic normal cells. By multiparameter analysis, this population of candidate normal stem cells could be separated from contaminating leukaemic CD34+ CD19- CD45- cells, which were detected in 11 of the 12 patients within the CD34+ CD19- compartment.
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PMID:Flow cytometric identification of candidate normal stem cell populations in CD45-negative B-cell precursor acute lymphoblastic leukaemia. 950 32


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