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

Over the last 15 years, infrared (IR) spectroscopy has developed into a novel and powerful biomedical tool that has multiple applications in the field of haematology. By revealing subtle alterations in both the conformation and concentration of key macromolecules, such as DNA, protein and lipids, IR spectroscopy has been employed to investigate multiple aspects of leucocyte physiology. IR spectroscopy has been used, for example, to diagnose and prognose leukaemia; to characterise differentiation and apoptotic processes; to predict drug sensitivity and resistance in leukaemic patients undergoing chemotherapy; to monitor the response of leucocytes to chemotherapy and to perform human leucocyte antigen matching for bone marrow transplant patients. Such studies have provided insight into pathogenic mechanisms underlying specific leucocyte disorders, especially leukaemia. While it is likely to be some considerable time before IR spectroscopy is sufficiently developed to displace the established technologies, IR spectroscopy has the potential to become a valuable analytic tool in basic and clinical haematology.
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PMID:Biomolecular characterisation of leucocytes by infrared spectroscopy. 1733 77

To define the role of quantitative graft composition and donor killer-cell immunoglobulin-like receptor (KIR) genotype in clinical outcome following unmanipulated peripheral blood stem cell transplantation (PBSCT) from human leucocyte antigen (HLA)-identical siblings, 43 consecutive transplants for haematological malignancies were analysed retrospectively. Twenty-four patients underwent myeloablative conditioning and 19 received busulphan/fludarabine-based reduced intensity conditioning (RIC). In patients with acute myelogenous leukaemia or myelodysplastic syndrome (AML/MDS; n = 18), no relapse occurred following transplants meeting both a high (above median) natural killer (NK) cell count and missing HLA-ligand(s) to donor's KIR(s), compared to all other AML/MDS patients (0% versus 44%; P = 0.049). Missing HLA-B and/or HLA-C ligand combined with missing HLA-A3/11 (KIR3DL2 unblocked) predicted for reduced relapse incidence regardless of diagnosis or conditioning type (P = 0.028). Moreover, in AML/MDS patients, this constellation predicted superior overall survival (OS) (P = 0.046). Transplants with more than two different activating donor KIRs were associated with an increased risk for non-relapse mortality (NRM), both by univariate and multivariate analysis. Quantitative graft composition had a significant impact exclusively in RIC transplants. Here, a trend towards reduced relapse incidence was found in patients receiving high numbers of NK cells (16% versus 54%; P = 0.09). In patients receiving high versus low T cell numbers, OS was superior (83% versus 37%; P = 0.01), due mainly to reduced NRM (0% versus 33%; P = 0.046). By multivariate analysis, relapse risk was decreased significantly in patients receiving high NK cell numbers (P = 0.039). These data suggest that both the number of transplanted NK cells and the donor KIR genotype play a role in graft-versus-malignancy mechanisms in HLA-identical PBSCT.
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PMID:Impact of natural killer cell dose and donor killer-cell immunoglobulin-like receptor (KIR) genotype on outcome following human leucocyte antigen-identical haematopoietic stem cell transplantation. 1749 20

Imatinib currently represents the standard treatment in the early chronic phase of chronic myelogenous leukemia (CML), thanks to the high percentage of cytogenetic complete remission achieved, but it is yet unclear to what extent it can eradicate leukemia. Therefore, different vaccination strategies have been suggested, mainly based on the exploitment of the junctional peptides spanning the fusion region of the Bcr/Abl proteins. To identify new potential immunologic targets, 63 Philadelphia chromosome-positive patients and 6 BCR/ABL-positive cell lines were tested in nested reverse transcriptase PCR to detect the presence of BCR/ABL transcripts arising from the alternative splicing of the main BCR/ABL transcripts. We could detect BCR/ABL transcripts with junctions between BCR exon 1, 13, or 14 and ABL exon 4 in approximately 80% of patients and 84% of cell lines, beside the main fusion transcripts. Translation products of these transcripts were characterized at their COOH terminus by a large amino acid portion derived from the out of frame (OOF) reading of ABL gene. These proteins were detected in BCR/ABL-positive cell lines by immunoprecipitation and immunohistochemistry. Finally, we determined whether OOF-specific CD8+ T cells could be found in the peripheral blood of CML patients and whether they could acquire effector function following in vitro sensitization with OOF-derived peptides predicted to bind to human leucocyte antigen (HLA)-A2 and HLA-A3 molecules. We detected the presence of OOF-specific CD8+ T cells in four of four patients studied, and in one case, these T cells exhibited specific cytotoxic activity against both peptide-pulsed targets and autologous primary CML cells.
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PMID:Alternative BCR/ABL splice variants in Philadelphia chromosome-positive leukemias result in novel tumor-specific fusion proteins that may represent potential targets for immunotherapy approaches. 1754 10

The impact of human leucocyte antigen (HLA) class I expression intensity and killer-cell immunoglobulin-like receptor (KIR)-mismatch was investigated on natural killer (NK)-cell mediated lysis of B-lineage leukaemic blasts from 21 paediatric patients in vitro. Blast susceptibility to standardised NK-activity and HLA-expression differed widely. A clear association between HLA-molecules/cell (range 442 000-13 000) and specific lysis (mean 59%, range 13-98%) was observed (r(2) = 0.68). A compound model incorporating HLA-expression and KIR-ligand-mismatch provided an even stronger association (r(2) = 0.87), whereas KIR-ligand-mismatch alone was not significant. Assessment of these factors might identify patients who could benefit from NK-mediated graft-versus-leukaemia effects after mismatched stem cell transplantation.
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PMID:Intensity of HLA class I expression and KIR-mismatch determine NK-cell mediated lysis of leukaemic blasts from children with acute lymphatic leukaemia. 1755 52

Almost all human malignant tumours exhibit strong telomerase activity, but normal adult tissues, with a few exceptions, do not. hTERT (human telomerase reverse transcriptase) is an essential component of telomerase, and hence it can serve as a parallel sign in the diagnosis and prognosis of cancers. In the present study, we selected a sequence of hTERT containing two antigenic epitopes that have high affinity for HLA-A2 (human leucocyte antigen-A2) as a TAA (tumour-associated antigen) based on a peptide-motif scoring system. The sequence was obtained by reverse-transcriptase PCR and cloned into the Escherichia coli expression vector pGEX-4T-1. The expression product appeared in the form of inclusion bodies. Denatured inclusion-body extract was subjected to SDS/PAGE, and the gel band corresponding to the putative 38 kDa fusion protein (GST-hTERT major tumour-associated antigen) was excised, ground with PBS, mixed with Freund's adjuvant and used to inoculate mice, generating anti-TERT polyclonal antibodies. Western blotting using the leukaemia cell line THP-1 demonstrated that the antibodies were able to detect hTERT expression, implying the potential applicability of the antigenic peptides derived from hTERT as a universal marker in the diagnosis and prognosis of tumours.
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PMID:Characterization of a human telomerase reverse transcriptase sequence containing two antigenic epitopes with high affinity for human leucocyte antigen. 1786 23

In children with acute lymphoblastic leukemia (ALL) with isolated central nervous system (CNS) relapse and a human leucocyte antigen (HLA)-matched sibling, the optimal treatment after attaining second remission is unknown. We compared outcomes in 149 patients enrolled on chemotherapy trials and 60 HLA-matched sibling transplants, treated in 1990-2000. All patients achieved a second complete remission. Groups were similar, except the chemotherapy recipients were younger at diagnosis, less likely to have T-cell ALL and had longer duration (> or = 18 months) first remission. To adjust for time-to-transplant bias, left-truncated Cox's regression models were constructed. Relapse rates were similar after chemotherapy and transplantation. In both treatment groups, relapse rates were higher in older children (11-17 years; RR 2.81, P=0.002) and shorter first remission (< 18 months; RR 3.89, P<0.001). Treatment-related mortality rates were higher after transplantation (RR 4.28, P=0.001). The 8-year probabilities of leukemia-free survival adjusted for age and duration of first remission were similar after chemotherapy with irradiation and transplantation (66 and 58%, respectively). In the absence of an advantage for one treatment option over another, the data support use of either intensive chemotherapy with irradiation or HLA-matched sibling transplantation with total body irradiation containing conditioning regimen for children with ALL in second remission after an isolated CNS relapse.
Leukemia 2008 Feb
PMID:Outcomes after HLA-matched sibling transplantation or chemotherapy in children with acute lymphoblastic leukemia in a second remission after an isolated central nervous system relapse: a collaborative study of the Children's Oncology Group and the Center for International Blood and Marrow Transplant Research. 1803 18

CD8(+) cytotoxic T-lymphocytes (CTLs) have been proven, in multiple animal models, to be the most powerful antiviral and antitumor components of the immune system. We have developed a protocol to activate and expand tumor and virus peptide-specific CD8(+) T-lymphocytes from the peripheral blood of healthy, human trophic leukemia virus-1 (HTLV-1) seronegative human leucocyte antigen (HLA)-A*0201 individuals. A combination of density-based separation and culture conditions was employed to isolate dendritic cells (DCs), which are the most potent antigen-presenting cells (APCs), and T-lymphocytes. The DCs were pulsed with HLA-A*0201 binding peptides and cultured with autologous T-lymphocytes to generate peptide-specific CTLs. The CTLs were generated against a nine-amino-acid peptide from the Tax protein of HTLV-1. The CTLs were expanded according to a restimulation schedule employing peptide-pulsed autologous monocytes and low-dose interleukin-2 (IL-2) to numbers in excess of 100 x 10(6) cells following 5 weeks of culture. Expanded cells contained primarily CD3(+) T-cells, of which CD8(+) T-lymphocytes constituted greater than two-thirds of the cell population. Obtained CTLs exhibited potent antigen-specific lysis of peptide-pulsed target cells in a dose-dependent fashion in in vitro (51)Cr release cytotoxicity assay. This antigen-specific killing was shown to be HLA class I restricted and mediated by CD8(+) T-lymphocytes. Since the T-lymphocytes were obtained from HTLV-1 seronegative donors, the generation of peptide-specific CTLs represents reliable and reproducible elicitation of a primary immune response in vitro against naive antigens and subsequent expansion of generated CTLs for adoptive immunotherapy. (c) 1996 John Wiley & Sons, Inc.
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PMID:Generation and ex vivo expansion of HTLV-1 specific CD8+ cytotoxic T-lymphocytes for adoptive immunotherapy. 1862 15

The hematopoietic cell transplantation specific comorbidity index (HCT-CI) has been developed to identify patients at high risk of mortality after an allograft. Reduced-intensity/non-myeloablative regimens have decreased the non-relapse mortality (NRM) in elderly and/or heavily pretreated patients. We performed a retrospective study to assess whether HCT-CI may predict clinical outcomes in a cohort of 203 patients with non-Hodgkin's (NHL; n=108), Hodgkin's lymphomas (HL; n=26), and multiple myeloma (MM; n=69), who were transplanted from a human leucocyte antigen (HLA)-matched sibling (n=121) or an unrelated donor (n=82) after a reduced-intensity regimen (n=154) or a low-dose total body irradiation-based non-myeloblative regimen (n=49). Cumulative incidence of NRM was 5, 16 and 20% at 1 year and 6, 24 and 27% at 2 years, for patients with an HCT-CI of 0, 1-2 and > or =3, respectively. By multivariate analysis, HCT-CI significantly predicted NRM (hazard ratio (HR)=1.6, P=0.03), overall survival (OS; HR=1.62, P<0.001) and progression-free survival (PFS; HR=1.43, P=0.002). Moreover, the Karnofsky performance status was also significantly associated with OS and NRM (HR=1.62, P<0.001 and HR=2.12, P=0.04, respectively). Conditioning type did not affect outcome after stratifying patients by HCT-CI. In the light of our study, all future prospective trials of the Gruppo Italiano Trapianti di Midollo (GITMO) will include the HCT-CI to stratify patients.
Leukemia 2009 Jun
PMID:The hematopoietic cell transplantation comorbidity index (HCT-CI) predicts clinical outcomes in lymphoma and myeloma patients after reduced-intensity or non-myeloablative allogeneic stem cell transplantation. 1919 65

Most tumour-associated antigens (TAA) are non-mutated self-antigens. The peripheral T cell repertoire is devoid of high-avidity TAA-specific cytotoxic T lymphocytes (CTL) due to self-tolerance. As tolerance is major histocompatibility complex-restricted, T cells may be immunized against TAA presented by a non-self human leucocyte antigen (HLA) molecule and transferred to cancer patients expressing that HLA molecule. Obtaining allo-restricted CTL of high-avidity and low cross-reactivity has, however, proven difficult. Here, we show that dendritic cells transfected with mRNA encoding HLA-A*0201, efficiently present externally loaded peptides from the antigen, Melan-A/MART-1 to T cells from HLA-A*0201-negative donors. CD8(+) T cells binding HLA-A*0201/MART-1 pentamers were detected already after 12 days of co-culture in 11/11 donors. The majority of cells from pentamer(+) cell lines were CTL and efficiently killed HLA-A*0201(+) melanoma cells, whilst sparing HLA-A*0201(+) B-cells. Allo-restricted CTL specific for peptides from the leukaemia-associated antigens CD33 and CD19 were obtained with comparable efficiency. Collectively, the results show that dendritic cells engineered to express defined allo-HLA peptide complexes are highly efficient in generating CTL specifically reacting with tumour-associated antigens.
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PMID:Dendritic cells engineered to express defined allo-HLA peptide complexes induce antigen-specific cytotoxic T cells efficiently killing tumour cells. 1928 96

In 1997-2003, a protocol for treatment of acute myeloid leukaemia (AML) (except promyelocytic leukaemia) was activated in four Swedish health care regions covering 50% of the national population. Based on cytogenetics and clinical findings, patients aged 18-60 yr were assigned to one of three risk groups. In this report we account for the long-term clinical outcome of enrolled patients. Patients received idarubicin and cytarabine in standard doses as induction therapy and consolidation courses included high-dose cytarabine. Allogeneic stem cell transplantation (allo-SCT) from an human leucocyte antigen-identical sibling was recommended in standard and poor-risk patients, whereas unrelated donor transplant was reserved for poor-risk patients. Autologous (auto-SCT) was optional for standard or poor risk patients not eligible for allo-SCT. Two hundred seventy-nine patients with de novo or secondary (9%) AML, median age 51 (18-60) yr, corresponding to 77% of all patients in the population, were included. Twenty (7%) patients were assigned to the good risk group, whereas 150 (54%) and 109 patients (39%) were assigned to standard- and poor-risk groups, respectively. Induction failures accounted for 55 patients; 16 early deaths eight of whom had white blood cell (WBC) >100 at diagnosis, and 39 refractory disease. Thus, complete remission (CR) rate was 80%. At study closure, the median follow-up time of living patients was 90 months. Median survival time from diagnosis in the whole group was 27 months and 4-yr overall survival (OS) rate was 44%. In good, standard, and poor risk groups, 4-yr OS rates were 60, 57 and 24%, respectively. Median relapse-free survival (RFS) time in CR1 was 25 months and RFS at 4 yr was 44%. Four-year RFS rates were significantly (P < 0.001) different between the three risk groups; 64% in good risk, 51% in standard risk and 27% in poor risk patients. One hundred-ten transplantations were performed in CR1; 74 allo-SCT (50 sibling, 24 unrelated donor), and 36 auto-SCT. Non-relapse mortality was 16% for allo-SCT patients. Outcome after relapse was poor with median time to death 163 d and 4-yr survival rate 17%. Three conclusions were: (i) these data reflect treatment results in a minimally selected population-based cohort of adult AML patients <60 yr old; (ii) a risk-adapted therapy aiming at early allogeneic SCT in patients with a high risk of relapse is hampered by induction deaths, refractory disease, and early relapses; and (iii) high WBC count at diagnosis is confirmed as a strong risk factor for early death but not for relapse.
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PMID:Results of risk-adapted therapy in acute myeloid leukaemia. A long-term population-based follow-up study. 1938 87


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