Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Allogeneic bone marrow transplantation (BMT) has been associated with a graft-vs.-leukemia (GVL) reactivity. Since T cell depletion of the bone marrow graft has decreased the risk of graft-vs.-host disease (GVHD), but has been associated with higher rates of leukemia relapse, GVL reactivity is probably caused by donor-derived T lymphocytes. Previously, we demonstrated that minor histocompatibility (mH) antigen-specific cytotoxic T lymphocyte (CTL) clones, generated from patients after BMT, are capable of major histocompatibility complex-(MHC) restricted lysis of (clonogenic) myeloid leukemic cells. Here, we investigated whether donor-derived leukemia-specific CTL clones can be generated in vitro, before BMT, using irradiated leukemic cells from a patient with acute myeloid leukemia as stimulator cells, and peripheral blood or bone marrow from the HLA genotypically identical sibling donor as responder cells. Several CTL lines were generated that showed specific lysis (> 50%) of the recipient leukemic cells in a 51Cr-release assay. Two of these CTL lines were cloned by limiting dilution in the presence of the irradiated recipient cells. Multiple leukemia-reactive, HLA class I and II-restricted clones with various specificities could be established. These alloreactive, antileukemic CTL clones may cause GVL reactivity after BMT, and may be used as adjuvant immunotherapy in the treatment of leukemia.
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PMID:Generation of leukemia-reactive cytotoxic T lymphocyte clones from the HLA-identical bone marrow donor of a patient with leukemia. 140 74

Acute myeloid leukemia (AML) blast cells (BC) express antigens that are commonly found on their normal counterparts. The leukemia colony-forming cell (L-CFC) subpopulation, identified by its ability to form leukemia colonies in vitro, is thought to be the stem cell population that produces BC. To ascertain the association between myeloid antigens on the BC and the L-CFC from the same patient, we compared the expression of CD14, CD15, CD33, p124 and HLA class I from 17 cases of AML. These particular myeloid antigens were studied because they are suitable targets in purging bone marrow for autotransplantation. We found no significant difference in the expression of CD14, CD15, CD33, and HLA class I on the BC and L-CFC from the same patient, although we observed considerable heterogeneity among different AML cases. Analysis of the progenitor cell antigen p124 revealed significant within-patient differences on the BC and L-CFC (p = 0.007), with a greater tendency for expression on the L-CFC. This heterogeneity may be due to differences in maturation stage of the L-CFC and BC. This information is important when L-CFC phenotype is used to determine the appropriate selection of antibodies for purging of residual disease in the context of auto-transplantation.
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PMID:Predictive value of flow cytometric analyses of blast cells in assessing the phenotype of the leukemia colony-forming cell (L-CFC) population in acute myeloid leukemia. 142 80

In a prospective study the incidence of allo-immunization and platelet refractoriness was investigated using a consequently leucocyte-poor blood product regime. Twenty-five previously non-transfused patients with acute leukaemia (11 men, 7 women) or autologous bone marrow transplantation for Hodgkin's or non-Hodgkin's lymphoma (2 men, 5 women) received at least 80 donor units of filtered red cells (filtration within 24 h after donation, leucocyte content 8.5 +/- 3.9 x 10(6)/U) and/or of platelet concentrate (produced by the buffy coat method, leucocyte content: 7.8 +/- 4.2 x 10(6)/U). A 1-hour recovery of 20% in three consecutive transfusions, in the absence of clinical factors known to impair increment, was defined as platelet refractoriness. HLA class I antibody screening with a panel of 60 cells was performed before the first transfusion and after 80 U of blood components. Of 25 patients who entered this study, 6 patients developed platelet refractoriness after a mean of 38 units of blood components (range 26-45 U); all 6 were female with a history of multiple pregnancies. In 19 patients regarded as non-refractory, no HLA antibodies were demonstrated (13 men, 6 women). This study, though limited in size, suggests that the use of blood products containing less than 1 x 10(7) leucocytes/donor unit prevents primary HLA class I immunization and platelet refractoriness.
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PMID:Prevention of primary HLA class I allo-immunization with leucocyte-poor blood components produced without the use of platelet filters. 148 73

Antiphosphotyrosine immunoblots were used to characterize tyrosine phosphorylated proteins after stimulation of the human TCR. Increased tyrosine phosphorylation was evident on at least 12 substrates within 2 min after ligation of the TCR with mAb. Analysis of the time course for increased tyrosine phosphorylation revealed distinct patterns. Increased phosphorylation of 135-kDa and 100-kDa substrates was evident within 5 s, whereas increased phosphorylation of the TCR-zeta-chain required several minutes after treatment with anti-CD3 mAb. This rapid cellular tyrosine phosphorylation occurred independent of the cell cycle, as it occurred after stimulation of resting T cells, T cell blasts, and the Jurkat T cell leukemia line. When the TCR complex was cross-linked together with the CD4 receptor by heteroconjugate anti-CD3/CD4 mAb, an increased magnitude of tyrosine phosphorylation occurred, although no new substrates could be detected. The increased tyrosine phosphorylation of the 135-kDa and 100-kDa substrates was specific in that anti-HLA class I, anti-CD6, anti-CD7, and anti-CD28 antibodies did not cause increased tyrosine phosphorylation. Anti-CD4 stimulation of resting T cells did not cause increased tyrosine phosphorylation of pp100 and pp135, suggesting that the CD4-associated kinase, lck, does not account for the tyrosine phosphorylation observed after TCR stimulation. Similarly, pharmacologic treatment of cells with phorbol ester and calcium ionophore did not cause increased tyrosine phosphorylation of these substrates, indicating that activation of protein kinase C or phospholipase C does not account for these early increases in tyrosine phosphorylation. The time of onset of pp100 phosphorylation, and the magnitude of phosphorylation correlated with the magnitude of calcium mobilization when cells were stimulated with different forms of TCR stimulation. When cells were labeled with [3H]myoinositol and analyzed after stimulation by anti-CD3 mAb, increased tyrosine phosphorylation of the 135-kDa and 100-kDa substrates preceded the activation of phospholipase C, as measured by the appearance of inositol 1,4,5-trisphosphate. This occurred in both T cell blasts and in the Jurkat T cell line. Thus, these findings show that increased tyrosine phosphorylation is the earliest yet detected signal observed after ligation of the TCR complex, and furthermore suggest that tyrosine phosphorylation might link the TCR to the phosphatidylinositolbisphosphate hydrolysis signaling pathway.
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PMID:Increases in tyrosine phosphorylation are detectable before phospholipase C activation after T cell receptor stimulation. 168 50

Beta 2-microglobulin (beta 2m) constitutes the common light chain of both the MHC-encoded HLA-ABC molecules and a group of structurally related glycoproteins recognized by antibodies of the first cluster of differentiation (CD1a, CD1b and CD1c). These CD1 antigens appear similar to murine T1 and Qa molecules in terms of structure and tissue distribution, although the question of inter-species homology is controversial. A further group of alloantigens expressed predominantly on T cells has been reported however, with immunogenetic characteristics more closely analogous to the murine T1/Qa system than the CD1 antigens, although their precise identity remains ill-defined. Having previously shown that malignant B cells may express membrane CD1c, we examined leukaemic B-cells corresponding to early lymphoblastic differentiation (null- and common acute lymphoblastic leukaemia) through to the terminal plasma cell stage for the expression of other non-HLA class I beta 2m-associated molecules. It was found that leukaemic B-cells at intermediate/late stages of differentiation, represented by non-Hodgkin's lymphoma (B-NHL) and 'hairy-cell' leukaemia (HCL), had significantly higher beta 2m:HLA-ABC ratios than did the cells from other types of B-cell malignancy. Although leukaemic B cells with a demonstrable non HLA-ABC-associated beta 2m component expressed detectable levels of CD1c, and insignificant levels of CD1a and CD1b, the antigen density was insufficient to account for the excess beta 2m. In vitro stimulation of leukaemic B cells by phorbol ester substantially increased the expression of HLA-ABC and CD1c, but also accentuated further the difference between the expression of these molecules and that of beta 2m. There was no detectable beta 2m other than that associated with HLA-ABC and CD1 on the surface of malignant T cells by contrast. Our findings strongly support the existence, at certain stages of leukaemic B-cell differentiation, of an additional beta 2m component(s) other than that associated with HLA-ABC and CD1.
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PMID:The MHC class I associated beta 2-microglobulin (beta 2m) light chain is expressed in a molar excess over HLA-ABC and CD1 on the membrane of leukaemic B cells but not leukaemic T cells: evidence for further beta 2m-associated molecules. 171 10

The human T-lymphotropic virus type I (HTLV-I), the first human retrovirus to be characterized, is associated with adult T-cell leukaemia and a chronic progressive disease of the central nervous system termed tropical spastic paraparesis, or HTLV-I-associated myelopathy. Only 1% of individuals infected with HTLV-I develop clinical disease however. The various manifestations of an HTLV-I infection may be related to differences in the genetic backgrounds of individuals, infection with variant strains of HTLV-I, differences in viral tropism or host immune response to the virus. Whereas the humoral response to HTLV-I is well characterized, little is known about the human cellular immune response, such as the production of cytotoxic T lymphocytes. Here we report the presence of high levels of circulating HTLV-I-specific cytotoxic T lymphocytes in patients with HTLV-I associated neurological disease but not in HTLV-I seropositive individuals without neurological involvement. These cytotoxic T lymphocytes are CD8+, HLA class I- restricted and predominantly recognize the HTLV-I gene products encoded in the regulatory region pX. These findings suggest that HTLV-I-specific cytotoxic T lymphocytes may contribute to the pathogenesis of associated neurological disorders associated with HTLV-I.
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PMID:Circulating CD8+ cytotoxic T lymphocytes specific for HTLV-I pX in patients with HTLV-I associated neurological disease. 214 11

In the present study, immunotoxins (ITs) containing ricin A chain (RA) and anti-human T leukemia monoclonal antibodies SN1 and SN2 were used with or without alpha-interferon (IFN) and/or daunorubicin (DNR) for in vivo tumor suppression. SN1 and SN2 are directed toward two unique human T-leukemia-associated cell surface antigens, TALLA and GP37, respectively. As the tumor model, we used nude mice bearing ascitic tumors of Ichikawa, a human T acute lymphoblastic leukemia cell line. In initial studies, we investigated the effect of the IT injection schedule on the efficacy of ITs in the in vivo suppression of the ascitic tumors. Four doses of 20 micrograms each of SN1-RA and SN2-RA completely suppress the tumor growth in 100% of the treated mice when the IT treatment is initiated either 1 or 2 days after tumor inoculation of 1.6 x 10(7) Ichikawa cells into the mice. Subsequently, we investigated the potentiating effects of IFN and DNR on the in vivo antitumor activity of ITs. To this end, we chose to initiate the treatment 4 days after the tumor inoculation when IT treatment alone is only partially effective. ITs (10 micrograms each of SN1-RA and SN2-RA) plus IFN (2 x 10(5) IU) or ITs plus IFN plus DNR (5 micrograms) completely suppress tumor growth in 100% of the treated mice while similar treatment with any one of the three agents is only partially effective. Similar treatment with ITs plus DNR or IFN plus DNR results in complete suppression of tumor growth in 80% of the treated mice. These results were reproducible in a repeated experiment. To gain information about the mechanisms involving the IFN potentiation of IT activity, we carried out several experiments. The cell surface expression of TALLA and GP37 was slightly augmented by the in vitro incubation of Ichikawa cells with IFN as measured by fluorescence-activated cell sorter analysis. The degree of the increase in either TALLA or GP37 was significantly smaller than that of HLA class I antigens in the same experiment. In in vitro experiments, IFN did not show any significant cytotoxic activity against Ichikawa cells or augment the cytotoxic activity of ITs against Ichikawa cells. On the other hand, injections of IFN into nude mice augmented activity of macrophages and NK cells; however, Ichikawa leukemia cells were rather resistant to the NK cell lysis.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Synergistic potentiation of in vivo antitumor activity of anti-human T-leukemia immunotoxins by recombinant alpha-interferon and daunorubicin. 229 57

The expression of HLA class I was assessed on erythrocytes by haemagglutination with monoclonal antibodies to monomorphic epitopes on the heavy and light (beta 2-microglobulin) chains. Previously, enhancement of HLA class I expression was observed on erythrocytes of many patients with systemic lupus erythematosus (SLE) and chronic lymphatic leukaemia (CLL), and we have now tested erythrocytes from patients (and 130 normal controls) with other auto-immune diseases and renal and haematological disorders. The striking enhancement in patients with SLE and CLL was confirmed. A significant increase in expression was also observed in aplastic anaemia patients following bone marrow transplantation and in renal patients with primary glomerulonephritis who had received a transplant. No class I was expressed by erythrocytes from many patients with inherited haemoglobinopathies and high reticulocyte counts, which suggests that the enhancement in SLE patients cannot be accounted for by immature or young erythrocyte populations. The distribution of HLA-A and -B types in the patients with enhanced class I expression did not relate to those antigens previously detected more frequently on erythrocytes, B7(Bga), B17(Bgb), A28(Bgc), B8 or A10, and the enhancement was not associated with any particular HLA types.
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PMID:Erythroid HLA class I expression in 300 patients with haematological, renal and rheumatological disorders. 239 73

We studied the effects of gamma interferon (IFN-gamma) on HLA class I gene expression, differentiation, and proliferative capacity of K562 human leukemia cells. In the uninduced state, K562 cells show little or no class I gene expression but actively express the erythroid-specific gamma-globin gene as well as genes associated with cell proliferation, including the transferrin receptor, c-myc, and alpha-actin genes At both the surface protein and mRNA levels, IFN-gamma induces class I and beta 2-microglobulin gene expression, but does not alter the expression of the gamma-globin, transferrin receptor, c-myc, or alpha-actin genes. A 10-fold maximal induction of both class I surface protein and mRNA occurs at 48 h and is reversible upon withdrawal of IFN-gamma from the culture medium. In vitro nuclear run-on transcription assays were performed to directly establish that IFN-gamma exerts an early effect at the level of transcription, with maximal transcription rates occurring within 4 h. The difference between the time course of transcription induction and that of mRNA accumulation suggests that the regulation of class I gene expression in this human leukemic cell line also involves posttranscriptional mechanisms. Measurements of cell proliferation rates and cell cycle distribution, as well as the reversibility of the effects of IFN-gamma, demonstrate that the selective induction of class I genes in these cells occurs in the absence of differentiation.
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PMID:Gamma interferon and 5-azacytidine cause transcriptional elevation of class I major histocompatibility complex gene expression in K562 leukemia cells in the absence of differentiation. 243 Dec 85

We have examined subfractions of human thymocytes for the expression of novel differentiation antigens. Non-HLA alloantisera procured from multiparous women served as antibody probes. Thymocytes from five individuals were sequentially separated by discontinuous Percoll density gradient centrifugation and a peanut agglutinin (PNA) panning technique. Subfractions were selected and examined for their relative intensity of HLA class I and CD1 antigens as determined by cytofluorometric analysis. Two subfractions were characterized as follows: an immature population (Fr6 PNA-) expressed a high level of CD1 (OKT6 binding) antigen and a low level of class I HLA antigen; and a more mature fraction (Fr3 PNA-) expressed minimal amounts of CD1 antigen and relatively high levels of HLA class I molecules. Fr6 PNA+ and Fr3 PNA- thymocytes were tested for their reactivity with a panel of non-HLA alloantibodies as determined by cytofluorometric analysis. We observed that three alloantibodies demonstrated strong fluorescence staining with Fr6 PNA+ thymocytes only, whereas three other alloantibodies reacted with both the Fr6 PNA+ and the Fr3 PNA- subfractions. All six alloantibodies failed to react with peripheral T cells. However, the six antibodies did react with a panel of cultured T lymphoblastoid leukemic cells and fresh leukemic T cells. Blocking studies demonstrated that these alloantibodies do not bind beta 2-microglobulin-associated determinants. These results suggest that the alloantibodies detect thymocyte differentiation antigens (TDA) that are shared by or are cross-reactive with antigens expressed on certain leukemia T cells. The non-beta 2m-associated TDA antigens are not expressed on normal resting T cells.
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PMID:Serological identification of thymocyte differentiation antigens. 245 87


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