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

The close association between adult T-cell leukemia (ATL) and human T-cell leukemia virus type I (HTLV-I) has been established. Nevertheless, the mechanism of progression of ATL by HTLV-I infection is still uncertain, because the virus contains no typical oncogene and no significant expression of the viral RNA has been generally found. I propose a model of leukemogenic process in ATL based on our cytogenetic data and molecular results in the literature. It seems that the rearrangement of some proto-oncogene and alpha-chain gene of the T-cell antigen receptor (TCR-alpha) is necessary for the development to overt ATL. A deficiency in the rearrangement of proto-oncogene to TCR-alpha may result in only a minor proliferation of abnormal lymphocytes and remain in the preleukemic state of ATL or in the HTLV-I carrier state.
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PMID:Cytogenetic implication in adult T-cell leukemia. A hypothesis of leukemogenesis. 198 42

The mechanisms whereby RNA leukemia viruses cause T lymphocyte leukemias or lymphomas after a long latent period are not understood. We report here that infection of human T lymphocyte lines with a murine leukemia virus results in up-regulation of a number of lymphocyte-specific cell surface Ag. These proteins include CD2, CD3, CD4, the TCR, and MHC class I Ag. The expression of other cell surface proteins, such as LFA-3, are unaffected by the presence of the retrovirus. This up-regulation occurs at the level of the mRNA transcripts encoding these proteins, and is the result of increased transcription of the respective genes. The increases in transcription are the result of a trans-activation process by the leukemia virus. The transient introduction of chimeric genes consisting of MHC class I gene promoter sequences attached to the reporter gene CAT into human T cells containing murine retrovirus produces stimulated transcription of the reporter gene. Subgenomic portions of the murine leukemia virus containing the long terminal repeats and the 5' untranslated region are sufficient to produce transactivation of the same set of T cell genes as the whole leukemia virus. The finding that murine leukemia viruses enhance transcription and expression of a group of T cell surface proteins, all of which have been reported to be capable of transducing an activating signal to the lymphocyte, may be relevant to the pathophysiologic mechanisms whereby these viruses induce leukemias and lymphomas.
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PMID:trans-Activation of genes encoding activation-associated human T lymphocyte surface proteins by murine retroviral sequences. 200 5

An 8;20 chromosomal translocation was observed in the leukemia cells of a 3-year-old girl. To our knowledge, this is the first report of this translocation in de novo acute leukemia. This chromosomal defect was present in the leukemia cells at diagnosis and also at relapse, but remission bone marrow cells had the 46,XX karyotype. By morphologic and cytochemical criteria the leukemia was myeloid but these features were more lymphoid when the leukemia recurred. However, the immunophenotype was consistent with myeloid leukemia and did not change at relapse. No evidence for either immunoglobulin or TCR gene rearrangement was observed.
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PMID:8;20 chromosomal translocation in a case of acute leukemia. Cytogenetic, immunophenotypic, ultrastructural, and molecular characteristics. 200 3

Recent technological advances, in both hardware and software, and availability of various monoclonal antibodies (MoAb) for membrane antigens of blood cells have expanded the application of flow cytometry (FCM) in medicine. In the haematology laboratory, FCM has been used mainly for assessment of leukemia and lymphoma and for determination of lymphocyte subsets. In acute leukemia, FCM is useful to classify ALL accurately, particularly for bi phenotypic or mixed lineage leukemia. In lymphocyte subset determination, we found that the use of magnetic beads to remove contaminating monocytes and some granulocytes to purify the lymphocyte-population is helpful in clarify the subsets. We present data describing the age dependent variation in lymphocyte subsets in the pediatric population. In early life (up to 2 years old), CD4 (+) 2H4 (+) lymphocyte overwhelmed CD4 (+) 2H4 (-) cells, implying predominance of suppressor-inducer activity. We also presented some cases of markedly increased double negative T cells (gamma/delta TCR) and a rare case of double positive (CD4+, CD8+) T cells.
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PMID:[Application and usefulness of flowcytometry in the haematology laboratory]. 204 Dec 14

Molecular analysis and blast colony assay were performed on patients with Philadelphia chromosome-positive acute leukemia (Ph+ AL). All patients were diagnosed as ALL- L2 and 3 were My+ ALL. Nine of the 12 cases had rearranged immunoglobulin heavy chain, and 4 had rearranged TCR beta. TCR gamma rearrangement was noted in 3 patients, and TCR delta involvement was also noted in 6 patients. Clonal culture analysis revealed that leukemia cells of M-BCR rearranged Ph+ AL cases had a potential to proliferate by myelopoietic CSFs and ILs, however, M-BCR nonrearranged Ph+ AL did not. These results indicate biological and immunogenotypic heterogeneity of Ph+ AL.
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PMID:[Immunogenotypic and clonal culture studies in Philadelphia chromosome-positive acute leukemia]. 206 75

Clonality in the non-neoplastic T cell population was investigated in 21 patients with B cell chronic leukemic (B-CLL) or multiple myeloma (MM) by probing for TCR beta chain gene rearrangements using Southern blot analysis. In three patients with a benign form of B-CLL (stage 0), and in one patient with smoldering MM, evidence was found for predominant T cell clones. As cellular immunity against the malignant cells may be important in leukemia, the results are discussed in view of the potential role of T cell immunity in B-CLL and MM.
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PMID:Presence of clonal T cell populations in chronic B lymphocytic leukemia and smoldering myeloma. 213 53

A 17-year-old male with bilineal hybrid acute leukemia is described. Two-color flow cytometric analysis of blast surface phenotype revealed that there were two groups of blasts which showed either CD 10+ CD 19+ CD 13- CD 33- or CD 10- CD 19- CD 13+ CD 33+, but not both. He developed a complete remission by treatment with vincristine, prednisolone, adriamycin, and L-asparaginase. After 8 months, however, leukemia relapsed and lymphoid blasts were dominant. Cytogenetic analysis at presentation showed 46,XY,t(3;9)(p21;p22), and at relapse it showed 46,XY,t(1;3;9)(1pter----1q32::3p25----3pter;3 qter----3p21::9p22----9pter; 9qter----9p22::3p21----3p25::1q32----1q ter),t(2;19)(p21;q13). Analysis of the heavy chain joining region at diagnosis showed three hybridizing bands, all rearranged, but at relapse only one rearranged band. Analysis of the constant region for the beta T-cell receptor gene (TCR beta) both at diagnosis and at relapse showed one rearranged and one germline band, suggesting that rearrangement of one allele of TCR beta of not only lymphoid but also myeloid blasts occurred. It is considered that the target cell of lymphoid leukemia cells and that of myeloid leukemia cells at diagnosis were the same, which differentiated to two lineages, and the clone which evolved from lymphoid lineage proliferated at relapse.
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PMID:Transformation of bilineal hybrid acute leukemia to acute lymphoid leukemia: a case report with serial analyses of cytogenetics and gene rearrangement. 216 90

We describe 5 cases of adult T-cell leukemia (ATL) carrying translocations at chromosome 14q11, where the genes for alpha- and delta-chains of the T-cell receptor (TCR alpha/delta) reside (Croce et al., 1985; Isobe et al., 1988). Since the TCR alpha/delta locus is the region where several types of chromosome translocations occur in T-cell tumors, rearrangements of the TCR alpha/delta locus in those ATL cases were studied as a first step to characterize these translocations at the molecular level. For this purpose we have generated an extensive series of probes to define the specificity and the diversity of rearrangement occurring at the widely spanned J alpha-C alpha locus and the complex D delta-J delta-C delta-V delta 2 locus. Using a set of probes, we have found the deletion of the TCR delta locus in all ATL cases, and at least 2 rearrangements in the J delta locus in each case of ATL. It is possible that translocations in the TCR alpha locus may be involved in ATL.
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PMID:Rearrangements in the human T-cell-receptor alpha-chain locus in patients with adult T-cell leukemia carrying translocations involving chromosome 14q11. 216 36

Binding of cognate Radiation leukemia virus (RadLV) by the C6VL/1 thymoma involves a subset of TCR molecules in association with CD4 molecules expressed by that cell line. A CD4- variant of C6VL/1 has now been isolated which also has RadLV binding capacity. Stable expression of the TCR, class I, and CD5 molecules but not Thy1.2 and CD4 molecules has been demonstrated, and the C6VL/1 origin of this cell has been confirmed by Southern blot analysis using probes specific for the TCR beta chain gene. This cell line has maintained binding capacity for RadLV/C6VL prepared as an immunoabsorbent matrix, but unlike the parent C6VL/1 cell line, binds significantly less well to the related RadLV/VL3 isolate. Binding of the variant cell line to RadLV/C6VL can be completely inhibited by anti-clonotypic antibody to the TCR but only weakly by anti-H-2Kb antibody used at the same concentration. These data suggest that the TCR on C6VL/1 can interact with RadLV in the absence of any co-receptor function of CD4 and implicates the TCR as a sufficient receptor for retrovirus.
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PMID:Unique role for the T cell receptor in retrovirus binding by the C6VL thymoma. 217 45

We have derived T cell lines from mice inoculated with Gross leukemia virus, which appear to represent early T cell developmental stages and to reflect normal T cell development. These cell lines may provide a breakthrough in the study of T cell development as Abelson transformants have done for the study of B cell development. Analysis of the TCR gene expression in these cell lines reveals that the sequence of rearrangement and expression of each TCR gene is not strictly ordered. Expression of RNA for the TCR alpha and -beta genes appears to be coordinated with rearrangement at the alpha and beta loci. This is not the case for gamma gene expression. Availability of the homogeneous populations of cells represented in these cells lines allows for a more detailed molecular analysis of T cell development than was previously possible.
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PMID:T cell receptor genes and T cell development in virus-transformed early T cell lines. 230 15


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