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

In an attempt to explore T-cell functions shortly after allogeneic bone marrow transplantation more fully, IL2- and IL4-dependent proliferation was assessed on CD4+ TCR alpha beta+ T-cell clones derived 4-6 weeks after transplantation. Both allogeneic pooled peripheral blood mononuclear cells and Epstein-Barr virus-transformed B-cell lines (BCL) could function as accessory cells (AC) for PHA activation of T-cell clones. Although minimal clonal proliferation was seen when the T-cell activation signal was BCL+PHA+IL4, a majority of the clones could undergo IL4-dependent proliferation after previous activation with AC+PHA+IL2. For certain clones, IL4 also showed an additive effect with IL2. Thus, IL4 was a growth factor for a majority of the investigated posttransplant T-cell clones, and in vivo modulation of IL4-dependent T-cell functions may thus become a future therapeutic possibility to enhance graft-versus-leukaemia effects in bone marrow transplant recipients.
 ...
PMID:IL2- and IL4-dependent proliferation of T-cell clones derived early after allogeneic bone marrow transplantation: studies of patients with chronic myelogenous leukaemia. 135 May 37

Results concerning a possible link between susceptibility to natural-cell-mediated immune cytolysis and the multi-drug resistance (MDR) phenotype are conflicting. We evaluated in human acute lymphocytic leukemia the relationship between acquired drug resistance and susceptibility to cytolysis mediated by endogenous, interferon-activated, and interleukin-2-activated natural cytotoxic cells. Eight human leukemia drug-resistant/sensitive cell line pairs were evaluated; drug-resistant sub-lines included those selected for primary resistance to adriamycin, etoposide, teniposide, vincristine, and vinblastine. A majority of P-glycoprotein-positive MDR sub-lines displayed slight but statistically significant resistance to endogenous and/or interferon-activated natural-killer(NK)-cell-mediated lysis, as compared with the drug-sensitive parental type. P-glycoprotein-negative sub-lines displayed variable NK susceptibility; within this group, the variants selected for primary etoposide resistance were more susceptible to NK cytolysis than parental cells. Results of cold-target-inhibition experiments suggest that altered NK susceptibility does not arise solely from modulation of NK target recognition and adherence structures. IL2-activated killer (LAK) cells lysed both drug-sensitive and drug-resistant lines. Two MDR lines selected for primary etoposide resistance displayed enhanced LAK susceptibility. In contrast, the 2 variants selected for resistance to adriamycin exhibited partial resistance to LAK-mediated killing, which could be overcome at high effector-to-target ratios. Our results support the development of interleukin-2/LAK immunotherapy for the treatment of leukemias with acquired drug resistance.
 ...
PMID:The relationship between multi-drug resistance and resistance to natural-killer-cell and lymphokine-activated killer-cell lysis in human leukemic cell lines. 137 Apr 37

Two patients with hematologic relapse of chronic myelogenous leukemia (CML) following allogeneic BMT were treated by abrupt discontinuation of cyclosporine. Both patients rapidly attained complete hematologic and cytogenetic remission and remain free of disease with long follow-up. In the first patient, disappearance of CML was associated with the development of graft-versus-host disease (GVHD). In the second patient GVHD did not develop until after clearing of disease had been documented by cytogenetic analysis. Laboratory studies in the second patient disclosed the presence of lytic activity against both K562 and autologous CML cells that enhanced with IL2. Correlation with serial immunophenotyping data from this patient suggests that the effector for this graft-versus-leukemia (GVL) reaction could have been a T lymphocyte. Abrupt discontinuation of post-transplant immunosuppression with cyclosporine may represent a therapeutic approach to CML which has recurred following BMT. Moreover, investigation of this clinical phenomenon in subsequent cases may permit direct study of the cellular mechanisms involved in the GVL effect.
 ...
PMID:Hematologic relapse of chronic myelogenous leukemia following allogeneic bone marrow transplantation: apparent graft-versus-leukemia effect following abrupt discontinuation of immunosuppression. 142 99

Two T-cell lines were established from peripheral blood mononuclear cells of two Moroccan patients with tropical spastic paraparesis and then named PR52 and PR144. The two cell lines showed a T lineage of activated CD4+ with high density of Tac+ (IL2 receptor). No expression of CD8 was observed. The virus particles were detected by reverse transcriptase activity and the viral antigens were also detected by immunofluorescence (IF) and Western blot. After six months of culture greater than 90% of the cells exhibited HTLVI antigen by IF. Lysate virus particles on Western blot analysis revealed p19,p24, and p53 gag protein similar to those detected in C91/PL virus particles from an adult T-cell leukemia (ATL) patient. gp46 and gp61 were also weakly detected. These two T-cell lines established will serve as substrate for further comparative studies on TSP and ATL isolates.
 ...
PMID:Establishment of T-lymphoid cell lines from Morroccan patients with tropical spastic paraparesis. 152 May 34

The effect of phorbol myristate acetate (PMA) on the expression of interleukin 2 receptors (IL-2R), production of IL-2 and IL-2-dependent proliferation of acute lymphoblastic leukemia T cells (T-ALL cells) from 10 patients was studied. First, the effect of PMA on the expression of cell surface markers was assessed: a decrease of CD3 and CD4, and an enhanced expression of CD8 molecule were observed on T-ALL cells. Moreover, PMA exhibited an heterogenous effect on various activation-associated molecules such as a decreased expression of transferrin receptor and T10 molecule and an induced expression of 4F2 and CD9 molecules. It is known that functional high-affinity IL-2R are composed of at least two IL2 binding molecules, the alpha (p55) and beta (p70) chains. We found that PMA induced the expression of both IL-2R alpha and IL-2R beta chains, as well as IL-2 production by T-ALL cells. These effects were time- and dose-dependent. Cross-linking experiments with 125I-labelled recombinant IL-2 (125I-rIL-2) revealed both p55 (IL-R alpha) and p70 (IL-2R beta) IL-2-binding polypeptides, whereas binding equilibrium assays on PMA-treated cells demonstrated the presence of a low number (31-413) of high-affinity binding sites/cell in five out of six cases analysed, as well as intermediate affinity IL-2R (1234-3919 sites/cell) in four out of six cases, according to the time of incubation with PMA. In two cases tested high-affinity IL-2R on PMA-treated T-ALL cells could internalize 125I-rIL-2 at 37 degrees C. PMA alone enhanced the spontaneous proliferation of T-ALL cells in three cases, whereas a clear synergy between IL-2 and PMA could be detected in three patients' cells. Moreover, exogenous rIL-2 enhanced cell proliferation of PMA-preincubated T-ALL cells in four cases studied. Taken together, these observations indicate that a short-term incubation of T-ALL cells with PMA can activate the IL-2/IL-2R system on these cells without inducing strong modifications of their differentiation status. These results thus suggest that this system may be involved in the proliferation process of some activated immature T cells.
Leukemia 1992 Apr
PMID:Phorbol myristate acetate-induced expression of high-affinity interleukin 2 receptors and production of interleukin 2 by human acute lymphoblastic leukemia T cells. 158 92

Immunotherapy with recombinant human interleukin-2 (IL-2) and allogeneic spleen cells has led to significant antitumor effects in B-cell leukemia- (BCL1) bearing mice following transplantation with T-lymphocyte-depleted allogeneic bone marrow cells. Graft versus leukemia (GVL) effects were studied in a model mimicking minimal residual disease following bone marrow transplantation (BMT). Lethally irradiated (BALB/c x C57BL/6)F1 recipients were reconstituted with 20 x 10(6) T-lymphocyte-depleted C57BL/6 bone marrow cells mixed with 10(4) to 10(6) BCL1 cells followed by administration of sequential increments of allogeneic C57BL/6 spleen cells; 10(6) cells on Day +1, 10(7) cells on Day +5, and 5 x 10(7) cells on Day +9, with or without concomitant IL-2 treatment (intraperitoneal injections of 20,000 U twice daily for 3 days) together with each spleen cell administration. All mice receiving 10(4)-10(6) BCL1 cells developed marked splenomegaly by Day +21 and all adoptive recipients of 10(5) spleen cells obtained from these mice developed leukemia within 21-36 days. Treatment of mice which received 10(4) BCL1 cells by either three courses of low dose IL-2 or three increments of allogeneic spleen cells alone and certainly by a combination of both resulted in normalization of splenomegaly on Day +21, but only adoptive recipients of 10(5) spleen cells obtained from mice treated by both allogeneic spleen cells and IL-2 (10/10) or allogeneic spleen cells alone (8/10) were disease free (greater than 100 days). Mice inoculated with 10(5) BCL1 cells developed mild splenomegaly on Day +21 after IL2 treatment alone, but showed no clinical evidence of disease following administration of allogeneic spleen cells or both allogeneic spleen cells and IL-2. Following adoptive transfer of 10(5) spleen cells obtained from each treated group no leukemia (greater than 100 days) was evident in recipients of spleen cells obtained from mice treated with both allogeneic spleen cells and IL-2 (10/10) whereas a partial effect was observed in mice treated by allogeneic spleen cells only (4/10). Mice inoculated with a high dose of BCL1 cells (10(6] showed some delay in onset of splenomegaly, but no curative antileukemic effects could be observed even following a synergistic combination of IL-2 and allogeneic spleen cells. Our data suggest that immunocompetent allogeneic lymphocytes may play an important role against leukemic relapse and thus cell therapy may be used therapeutically to treat minimal residual disease after BMT even following initial reconstitution with T-cell-depleted bone marrow cells.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Use of recombinant human interleukin-2 in conjunction with bone marrow transplantation as a model for control of minimal residual disease in malignant hematological disorders: I. Treatment of murine leukemia in conjunction with allogeneic bone marrow transplantation and IL-2-activated cell-mediated immunotherapy. 173 11

In conclusion, lessons from the animal model of lymphoid leukaemia suggest that in the setting of allogeneic BMT, under certain conditions GVL effects may be separable from GVHD; more specifically, GVL effects may be induced despite development of tolerance of donor cells against allogeneic host alloantigens. The latter phenomenon suggests that either curative GVL effects may be inducible despite subclinical GVHD or alternatively that effector cells of GVL may recognize different tumour-associated targets different from cell surface determinants of 'normal' alloantigens. Alternatively, effector cells of GVL may be distinguished from effector cells of GVHD. It is tempting to suggest that NK and IL2-aspirated NK cells may play a major role as effector cells of GVL in an MHC non-restricted fashion, different from classical CD8+ cytotoxic cells that certainly play a major role in GVHD and GVL. Once proven, the latter hypothesis may help develop new and safer therapeutic approaches since NK cells and products of the NK cell family are unlikely to play a major role, if any, in GVHD. The feasibility of induction of GVL-like effects by MHC non-restricted effector cells, such as that observed by CMI, most likely through cytokine-activated NK cells, seems promising because such effector mechanisms may be utilized clinically through either adoptive transfer of in vitro-activated lymphocytes or activation of lymphocytes in vivo by administration of cytokines such as IL2 and alpha IFN. Similarly, induction of CCI following ABMT may permit establishment of GVL-like effects with no major risk of GVHD. Our animal models suggest that both approaches may be beneficial and perhaps even combined. From a practical standpoint, activation of antitumour effector cells in vivo is much more feasible, in comparison with the cumbersome and expensive technologies for large-scale in vitro manipulation of IL2-activated 'LAK' cells or tumour-infiltrating lymphocytes ('TIL') at dose ranges required for obtaining clinically meaningful responses. No less important is the fact that more potent immunotherapy may be inducible by cytokine combinations (such as IL2 and alpha IFN). We are currently investigating additional cytokine combinations in order to attempt to optimize antitumour effects inducible by allogeneic and syngeneic lymphocytes since it appears logical that amplifying in vivo antitumour responses by multiple cytokine combinations may yield better antitumour effects.
 ...
PMID:Control of relapse due to minimal residual disease (MRD) by cell-mediated cytokine-activated immunotherapy in conjunction with bone marrow transplantation. 195 88

The effect of immunocompetent lymphocyte depletion on precursors and effector cells of IL2 activated non-MHC restricted cytotoxic cells (LAK) generated from bone marrow (BM) or peripheral blood was investigated. Lymphocyte depletion was carried out by using Campath-1, a monoclonal rat anti-human lymphocyte antibody recognizing CDW52, that binds human complement and is used routinely in clinical bone marrow transplantation (BMT). The results indicate that LAK precursors derived from BM cells are sensitive to Campath-1 treatment, while a variable degree of sensitivity was demonstrated in LAK precursor cells derived from peripheral blood. In contrast, effector LAK cells generated in vitro were shown to be resistant to treatment with Campath-1 and complement. We hypothesize that if indeed IL2-dependent non-MHC restricted cytotoxic cells play a role in vivo in the immediate post-BMT period, a T lymphocyte depletion procedure such as the Campath-1 may have the capacity to reduce, at least temporarily, the graft-versus leukemia effects mediated by such anti-tumor effector mechanisms.
 ...
PMID:The effect of in vitro T lymphocyte depletion on generation of IL2-activated cytotoxic cells. 207 Jan 32

Graft-versus-leukemia (GVL) is a major component of the overall beneficial effects of allogeneic bone marrow transplantation (BMT) in the treatment of leukemia. Although several clinical trials have suggested a direct relationship between GVL effects and acute and chronic graft-versus-host disease (GVHD), it is not yet known whether GVL can be separated from GVHD. However, several investigations in murine models of human leukemia indicate that the two may be at least partially separable. Moreover, analysis of clinical data from the International Bone Marrow Transplant Registry suggest that allogeneic BMT may be more advantageous than syngeneic BMT, regardless of the GVHD. Likewise, T lymphocyte depletion is associated with an increased incidence of relapse, independently of GVHD. Recent investigations in murine leukemia suggest that GVL-like effects may be inducible following syngeneic BMT by recombinant cytokines with no overt GVHD. Taken together, current data in experimental animals and man suggest that GVL may be at least partially separable from GVHD. Hence, further understanding of effector and target cells of GVL as well as our ability to induce antitumor effector cells, especially those that are MHC nonrestricted, may lead to new approaches for potentiating anti-tumor effector mechanisms without inducing severe, clinically overt GVHD. Successful attempts in these directions may also lead to improved results following autologous BMT as a result of activation of GVL-like effects by recombinant cytokines that are capable of activating effector cells with anti-leukemic activity in vivo, such as recombinant human IL2, alpha interferon or perhaps a synergistic combination of factors.
 ...
PMID:The graft-versus-leukemia (GVL) phenomenon: is GVL separable from GVHD? 225 54

Although high-dose chemoradiotherapy used for conditioning prior to autologous bone marrow transplantation (BMT) represent an effective tool for eradication of certain malignant hematological disorders, relapses indicate that the last tumor cell is unlikely to be completely eradicated. We are investigating several approaches for controlling residual tumor cells escaping from chemoradiotherapy by cellular adoptive immunotherapy and amplification of natural defense mechanisms, using recombinant human IL2 (Cetus, Emeryville CA), in a murine model of leukemia/lymphoma disease (BCL1).
 ...
PMID:Immunotherapy in conjunction with autologous bone marrow transplantation. 231 4


1 2 3 4 5 6 Next >>