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

Clinical animal models and in vitro data afford evidence for anti-leukaemia immunity. Many reports have underlined the interest of interleukin-7 (IL-7) use in cancer and its pivotal role in immune recognition. This cytokine, initially identified as a B cell growth factor, enhances the anti-tumour properties of immune effector cells via T lymphocyte activation, increased specific cytotoxicity and cytokine secretion. Nonetheless, few data are available regarding the effect of IL-7 on the expression at the leukaemia cell surface of molecules involved in the immune response, which defective expression could induce tolerance or anergy. This prompted us to study the effects of IL-7 on 20 cases of acute myeloid leukaemia (AML) and 9 cases of lymphoid leukaemia (ALL), in comparison with gamma-interferon, a potent inducer of immune regulation molecule expression. In AML and ALL, IL-7 increased MHC class I molecule expression, while class II molecules were weakly modified. The expression of the tumour necrosis factor family members CD40 and Fas/CD95, together with the adhesion molecules ICAM-1/CD54 and CD58/LFA-3, was also increased in both types of leukaemia. The IL-7 was an efficient inducer of B7-2/CD86 expression in AML and ALL, while increased expression of B7-1/CD80 was only observed in AML. In the corresponding, co-cultured T lymphocyte population, IL-7 more particularly increased B7-1/CD80 and CD58/LFA-3 expression. Finally, pre-incubation of leukaemic cells with IL-7 increased the proliferation of responding, normal allogenic T lymphocytes and their secretion of gamma-IFN and IL-2 in mixed the lymphocyte-tumour reaction. We concluded that IL-7 is efficient at increasing the membrane expression of molecules which are central for the development of the immune response, and at improving allogenic immune recognition. The clinical implications of such data require further in vivo investigation.
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PMID:Differential modulation of immune recognition molecules by interleukin-7 in human acute leukaemias. 1021 Jul 78

In B-chronic lymphoproliferative disorders (B-CLD) adhesion molecules (AM) have been investigated in order to explain the variable biologic behavior and dissemination patterns and to assess their contribution to the differential diagnosis and prognosis of these diseases. The main AM studied either by immunohistochemistry on lymph node sections or by flow cytometry in blood and bone marrow specimens are L-selectin, CD11a/CD18 (LFA-1), CD54 (ICAM-1), CD44 (HCAM), CD11c/CD18 (gp150/95), and CD49d/CD29 (VLA-4). Among B-CLD, hairy-cell leukemia (HCL) and follicular lymphoma (FL) show a uniform AM expression pattern. Thus, HCL is characterized by high CD54, CD44, VLA-4, CD11c, and CD18 and by low or absent CD11a and L-selectin, whereas FL confined to the lymph nodes is characterized by high CD11a, CD18, and CD54 expression. Diffuse growth and dissemination of FL is associated with alteration in the AM profile. Mantle-cell lymphoma (MCL) seems to be characterized by low or absent L-selectin and CD11c and high CD54 expression, especially compared with B-chronic lymphocytic leukemia (B-CLL). B-CLL is the most heterogeneous among all B-CLD with respect to AM expression. In general, low LFA-1 and CD54, high L-selectin and CD44, and variable CD11c characterize B-CLL. Cases with splenomegaly as their prominent feature bear high CD11a, CD18, CD29, and CD11c on the surface of the leukemic cells. Small lymphocytic lymphoma (SLL) shares the same AM phenotype with B-CLL, with the possible exception of LFA-1, which is strongly expressed on SLL cells. LFA-1 and CD54 are more frequently positive in lymphoplasmacytic lymphoma (LPL) as compared with B-CLL. Splenic lymphoma with villous lymphocytes differs from B-CLL by its high LFA-1, VLA-4, and CD54 and low L-selectin expression, whereas its high LFA-1 positivity can differentiate it from HCL. Surface and soluble AM have been investigated as possible prognostic markers in these diseases. Conflicting data exist concerning the prognostic significance of surface AM. However, high soluble (s)CD44 and CD54 levels in B-CLL and non-Hodgkin's lymphomas (NHL) are considered as adverse prognostic factors.
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PMID:Adhesion molecules in B-chronic lymphoproliferative disorders. 1031 87

This study was designed to determine whether the cytocidal activity of immunotherapy such as cytotoxic peripheral blood lymphocytes (PBL), lymphokine-activated killer (LAK) cells, and chimeric anti-CD20 mouse/human monoclonal antibody, IDEC-C2B8, overcome vincristine (VCR) resistance in cultured cell lines derived from human leukemia/lymphoma. In addition, the relation between the susceptibility to these immunotherapies and the expression levels of HLA class 1 and ICAM-1 as well as CD20 on the cell surface was analyzed. Three of six VCR-resistant cell lines were less susceptible to PBL cytotoxicity compared with wild-type cells, whereas the susceptibility was kept in the other three VCR-resistant cell lines. Four of six VCR-resistant cell lines were less susceptible to LAK activity and the other two cell lines were as sensitive to LAK cells as their wild-type counterparts. There was no correlation between the susceptibility for PBL cytotoxicity and the expression of HLA class 1 in both wild and VCR-resistant cells. In contrast, ICAM-1 in the two cell lines that showed decreased susceptibility for LAK cytotoxicity disappeared, although that in one cell line increased. IDEC-C2B8 was effective only against B-cell lines expressing CD20. One cell line in which the expression of CD20 increased was nearly six times more sensitive to IDEC-C2B8 than wild type. Thus, we concluded that the resistance to VCR in some tumor cell lines is associated with modified susceptibility for immunotherapies by the different expression of target molecules from those of wild-type counterparts.
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PMID:Cytocidal activity of PBL, LAK, and IDEC-C2B8 and expression of HLA class 1, ICAM-1, and CD20 in vincristine-resistant hematologic cell lines. 1033 83

Human T-cell leukaemia/lymphoma virus type 1 (HTLV-1) is a pathogenic retrovirus responsible for a number of inflammatory pathologies and adult T-cell leukaemia. Although T-cell tropic in vivo, HTLV-1 can infect a wide variety of cell types in vitro. Cell-to-cell spread of HTLV-1 may require specific binding of envelope to its cellular receptor, with other cell-surface molecules facilitating fusion. Here it is shown that intercellular adhesion molecule-1 or -3 (ICAM-1, ICAM-3) or vascular cell adhesion molecule-1 (VCAM-1) are required for syncytium formation of K562 with HTLV-1-infected MT2 cells but not C91-PL cells. The effect of ICAMs and VCAM-1 on MT2-induced fusion can be blocked by antibodies that bind beta-integrins. These fusion co-factor molecules are effective only when present in combination with HTLV-1 receptor-bearing cells and are not sufficient to mediate syncytium formation alone. The results suggest that engagement of HTLV-1-infected cells with susceptible target cells requires the simultaneous binding of viral envelope glycoprotein to the cellular receptor and co-factor molecules to beta-integrins. The tissue-specific expression of adhesion molecules might therefore influence HTLV-1 virus tropism and pathogenic changes associated with syncytium formation.
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PMID:Human T-cell leukaemia/lymphoma virus type 1 syncytium formation is regulated in a cell-specific manner by ICAM-1, ICAM-3 and VCAM-1 and can be inhibited by antibodies to integrin beta2 or beta7. 1037 60

The expression of five cellular adhesion molecules (CAMs), CD54, CD58, CD11a, CD29 and CD49d, was studied in 113 B cell non-Hodgkin's lymphomas (NHL) and in normal B cells from 12 control lymph nodes. Rather than reporting the percentage of positive cells, which does not discriminate between NHL subtypes, we quantified the intensity of CAM expression using flow cytometry. Apart from CD49d the expression of all these CAMs was statistically different among the NHL subtypes as defined by the REAL classification. Low grade NHL-small lymphocytic, follicular and mantle cell lymphoma--which are derived from quiescent cells and show an indolent disease course, expressed low levels of CAMs. Conversely, high grade NHL-diffuse large cell lymphoma--which are derived from proliferating cells and are clinically aggressive, expressed high levels of CAMs. These results indicate that in malignant NHL B cell tumour growth and clinical aggressiveness may be related to the adhesive capacities of the tumour cells.
Leukemia 1999 Sep
PMID:Quantification of cellular adhesion molecules on malignant B cells from non-Hodgkin's lymphoma. 1048 95

The expression of adhesion molecules on CD34+ cells in acute myeloid leukemia (AML) and B-lineage acute lymphoblastic leukemia (B-lineage ALL) was compared with that on the myeloid and B-lymphoid CD34+ cells in normal bone marrow. Bone marrow aspirates of 10 patients with AML, 8 patients with B-lineage ALL and of 6 healthy volunteers were examined. The phenotype of the CD34+ cells was determined with a double immunofluorescence method and flow cytometry. CD34+ cells in AML and B-lineage ALL showed a lower expression of VLA-2 and VLA-3 and a higher expression of ICAM-1 and LFA-3 than their normal bone marrow counterparts. AML CD34+ cells had less L-selectin but more VLA-5 on their surface membrane than normal myeloid CD34+ cells. B-lineage ALL CD34+ cells showed an overexpression of LFA-3. In individual patients deficiencies or over-expression of the beta1 integrin chain, VLA-4, PECAM-1 or HCAM also occurred. An abnormal adhesive capacity of the leukemic cells may influence their proliferation, their localisation and apoptosis. An aberrant expression of adhesion molecules may be used for the detection of minimal residual leukemia in these patients.
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PMID:Different expression of adhesion molecules on CD34+ cells in AML and B-lineage ALL and their normal bone marrow counterparts. 1048 74

The adhesive function of integrins is regulated through cytoplasmic signaling. The present study was performed to investigate the relevance of cytoplasmic signaling and cytoskeletal assembly to integrin-mediated adhesion induced by chemokines. Adhesion of T cells induced by chemokines macrophage inflammatory protein (MIP)-1alpha and MIP-1beta was inhibited by pertussis toxin, wortmannin, and cytochalasin B, suggesting that both G protein-sensitive phosphatidylinositol (PI) 3-kinase activation and cytoskeletal assemblies are involved. The chemokine-induced T cell adhesion could be mimicked by expression of small G proteins, fully activated H-RasV12, or H-RasV12Y40C mutant, which selectively binds to PI 3-kinase, in T cells, inducing activated form of LFA-1alpha and LFA-1-dependent adhesion to ICAM-1. H-Ras expression also induced F-actin polymerization which colocalized with profilin in T cells. Adult T cell leukemia (ATL) cells spontaneously adhered to ICAM-1, which depended on endogenous MIP-1alpha and MIP-1beta through activation of G protein-sensitive PI 3-kinase. H-Ras signal pathway, leading to PI 3-kinase activation, also induced active configuration of LFA-1 and LFA-1-mediated adhesion of ATL cells, whereas expression of a dominant-negative H-Ras mutant failed to do. Profilin-dependent spontaneous polymerization of F-actin in ATL cells was reduced by PI 3-kinase inhibitors. In this paper we propose that H-Ras-mediated activation of PI 3-kinase can be involved in induction of LFA-1-dependent adhesion of T cells, which is relevant to chemokine-mediated signaling, and that profilin may form an important link between chemokine- and/or H-Ras-mediated signals and F-actin polymerization, which results in triggering of LFA-1 on T cells or leukemic T cells.
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PMID:H-Ras signals to cytoskeletal machinery in induction of integrin-mediated adhesion of T cells. 1057 Mar 13

Most human myeloid leukemias express both class I and class II HLA and it has been postulated that leukemia-associated peptides are presented by those molecules. It is possible, however, that leukemia cells escape the immune surveillance by lacking expression of "costimulatory" molecules required for activating the immune response. Human erythroleukemia line (HEL) has been the subject of previous detailed studies demonstrating surface expression of bona fide HLA molecules but inability to stimulate allogeneic response of proliferative or cytolytic T cells. We found that an HLA-DR+ subclone (HEL-DR+) expresses LFA-1, LFA-3, ICAM-1, ICAM-3, but neither CD80 nor CD86 on the surface. Transfection of CD80 cDNA into HEL-DR+ cells induced the allogeneic response of purified T cells from both cord blood and peripheral blood of adult donors, demonstrating that CD80 expression could lead to accessory cell-independent activation of naive T cells. Priming allogeneic peripheral blood T cells by HEL-DR+/CD80+ also lead to generation of cytotoxic T lymphocytes that lysed both HEL-DR+/CD80+ and wild type HEL-DR+ equally well, confirming CD80 expression is required only in the CTL induction phase but not in the CTL effector phase. We established and maintained alloproliferative T cell clones from adult blood by stimulation with the HEL-DR+/CD80+ line. The clones could respond not only to HEL-DR+/CD80+ line but also to the HEL-DR+ line; however, the proliferative response to HEL-DR+/CD80+ was amplified and sustained compared to the short-lived response to wild type HEL-DR+ cells. Therefore, expression of CD80 by HEL-DR+ cells was determinant both to initiate and sustain the T cell response. These experiments support the hypothesis that lack of expression of "costimulatory" molecules for T cells contributes to leukemia escape from immune surveillance, and provide preliminary data for the use of CD80 transfection in the immunotherapy of human leukemia.
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PMID:The role of T cell costimulation by CD80 in the initiation and maintenance of the immune response to human leukemia. 1060 80

Modulation of integrin affinity and/or avidity provides a regulatory mechanism by which leukocyte adhesion to endothelium is strengthened or weakened at different stages of emigration. In this study, we demonstrate that binding of high-affinity alpha 4 beta 1 integrins to VCAM-1 strengthens alpha L beta 2 integrin-mediated adhesion. The strength of adhesion of Jurkat cells, a human leukemia T cell line, or MnCl2-treated peripheral blood T cells to immobilized chimeric human VCAM-1/Fc, ICAM-1/Fc, or both was quantified using parallel plate flow chamber leukocyte detachment assays in which shear stress was increased incrementally (0.5-30 dynes/cm2). The strength of adhesion to VCAM-1 plus ICAM-1, or to a 40-kDa fragment of fibronectin containing the CS-1 exon plus ICAM-1, was greater than the sum of adhesion to each molecule alone. Treatment of Jurkat or blood T cells with soluble cross-linked VCAM-1/Fc or HP2/1, a mAb to alpha 4, significantly increased adhesion to ICAM-1. These treatments induced clustering of alpha L beta 2 integrins, but not the high-affinity beta 2 integrin epitope recognized by mAb 24. Up-regulated adhesion to ICAM-1 was abolished by cytochalasin D, an inhibitor of cytoskeletal rearrangement. Taken together, our data suggest that the binding of VCAM-1 or fibronectin to alpha 4 beta 1 integrins initiates a signaling pathway that increases beta 2 integrin avidity but not affinity. A role for the cytoskeleton is implicated in this process.
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PMID:Alpha 4 beta 1 integrin/VCAM-1 interaction activates alpha L beta 2 integrin-mediated adhesion to ICAM-1 in human T cells. 1062 19

Immunologically committed lymphocytes, especially mature, leukemic B cells, proliferate then accumulate without further cell division in chronic lymphocytic leukemia patients (CLL). These mature, leukemic B cells often produce autoantibodies. Under normal circumstances, immunologically committed lymphocytes that are autoreactive are deleted by a programmed cell death mechanism. In CLL cells, these mechanisms appear to be inhibited; therefore, cells accumulate rather than be destroyed. To understand the mechanism by which cell survival is selected over death in CLL cells, we studied the role of beta2 integrins and their ligands in the regulation of apoptosis. CLL cells were treated with monoclonal antibodies directed against beta2 integrins. Antibodies directed against the I-domain of the alpha chain of CD11b/CD18 inhibited apoptosis. The identity of the physiological ligand or counter-receptor for beta2 integrins that was required for the inhibition of apoptosis induction was sought. The ligand iC3b, but not ICAM-1 or fibrinogen, was identified as a ligand that could prevent apoptosis of CLL B cells. Free iC3b levels were elevated in CLL patients indicating that this ligand is available in vivowhere it may interact with beta2 integrins on CLL B cells and sustain their viability by preventing activation of the programmed cell death pathway. Leukemia (2000) 14, 34-39.
Leukemia 2000 Jan
PMID:Role of beta2 integrins in the prevention of apoptosis induction in chronic lymphocytic leukemia B cells. 1063 74


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