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Biomedical subjects

O Bruserud

Publications and source records attributed to O Bruserud.

At least 55 records · Page 3Linked to original sources

Interleukin 4 responses in acute leukaemia patients with severe chemotherapy-induced leucopenia.

T lymphocyte functions in acute leukaemia patients with severe chemotherapy-induced leucopenia were investigated using 3 different approaches: (i) analysis of serum concentrations of the T cell cytokine interleukin 4 (IL4) demonstrated that serum IL4 levels increased during complicating bacterial infections. However, this response was modulated by a concomitant increase in serum levels of the potential IL4 antagonist soluble IL4 receptor alpha chain (sIL4R alpha). (ii) Even during leucopenia a subset of T lymphocytes derived from leucopenic patients expressed the activation markers CD25 (IL2 receptor), CD71 (transferrin receptor) and HLA-DR. (iii) Subsets of circulating CD4+ and CD8+ T lymphocytes could undergo clonogenic proliferation in vitro, and a majority of these clones secreted IL4. CD4+ clones showed higher IL4 levels than CD8+ clones. Our results indicate that T lymphocytes can be activated and contribute to cytokine responses in acute leukaemia patients with severe chemotherapy-induced cytopenia.

Adolescent↗

BCR/ABL leukemia oncogene fusion peptides selectively bind to certain HLA-DR alleles and can be recognized by T cells found at low frequency in the repertoire of normal donors.

Chronic myelogenous leukemia (CML) is characterized by the t(9;22) translocation that results in chimeric genes encoding bcr/abl fusion proteins. Junction-spanning sequences represent unique tumor-specific moieties that might be exploited therapeutically. We investigate here the binding of synthetic bcr/abl peptides to various HLA-DR alleles and their recognition by T cells from normal donors and CML patients. A 23-mer b3/a2 peptide bound very strongly to isolated HLA-DRB1*1101 (Dw5) and relatively strongly to DRB1*0301 (Dw3) and DRB1*0402 (Dw10) molecules, as estimated using a competition assay. It failed to bind to several other DR alleles, including three different DR4 alleles. In contrast, a 23-mer b2/a2 peptide bound only to the DRB1*0301 (Dw3) allele. Peripheral blood mononuclear cells from normal donors were sensitized in vitro against the b3/a2 peptide. After four repetitive stimulations, T cells responding to the peptide were found at low frequency in 5 of the 11 donors tested. Three of the five were HLA-DR11+, and all three of the DR11+ donors tested were found to respond. T cells recognizing bcr/abl peptides were not identified in any of the CML patients studied, regardless of HLA type. Finally, even peptide-reactive T-cell lines from normal donors were not stimulated by native CML cells in the absence of exogenous peptide. These results show the presence of low-frequency major histocompatability complex class II-restricted bcr/abl-responses in the normal T-cell repertoire of donors with certain HLA types, but suggest that unmodified tumor cells cannot be recognized by such peptide-sensitized T cells.

Amino Acid Sequence↗

Human T lymphocyte activation in the presence of acute myelogenous leukaemia blasts; studies of normal polyclonal T cells and T lymphocyte clones derived early after allogenic bone marrow transplantation.

T cell clones (CD4+CD8-TCR alpha beta+gamma delta- derived from bone marrow transplant recipients were stimulated with phytohaemagglutinin (PHA) +interleukin-2 (IL-2) in the presence of irradiated (50 Gy) peripheral blood mononuclear cells (PBMC) derived from acute Leukaemia patients (leukaemic PBMC containing more than 95% blast cells). Leukaemic PBMC could function as accessory cells during mitogenic T cell activation resulting in both T cell proliferation and a broad T cell cytokine response [IL-3, IL-4, IL-10, granulocyte/macrophage-colony-stimulating factor (GM-CSF) tumour necrosis factor alpha (TNF alpha) and interferon gamma (IFN gamma) secretion]. Blockade of IL-1 effects by adding IL-1 receptor antagonist together with PHA + IL-2 + leukaemia blasts increased T cell proliferation, whereas IL-6-neutralizing antibodies did not alter T cell proliferation. A qualitatively similar T cell cytokine response and a similar cytokine profile (highest levels detected for GM-CSF and IFN gamma) were detected when normal polyclonal T cell lines were stimulated with PHA in the presence of non-irradiated leukaemic PBMC. When leukaemic PBMC derived from 18 acute myelogenous leukaemia patients were cultured with PHA and cells from a polyclonal T cell line, increased concentrations of the T cell cytokines IFN gamma and IL-4 were detected for all patients. We conclude that T cell activation resulting in proliferation and a broad cytokine response can take place in the presence of excess acute myelogenous leukaemia blasts.

Adult↗

Human T lymphocyte activation in the presence of acute myelogenous leukaemia blasts: studies of allostimulated interferon-gamma secretion.

Normal peripheral blood mononuclear cells (PBMC responders) were cultured together with non-irradiated allogeneic PBMC (more than 95% leukaemia blasts) derived from patients with acute leukaemia (referred to as leukaemic PBMC stimulators). Cytokine secretion was determined as cytokine concentrations in supernatants. Both normal PBMC and enriched CD4+ and CD8+ T cells responded to allostimulation with interferon (IFN gamma) secretion. Interleukin-I (IL-1) receptor antagonist and IL-2-neutralizing antibodies decreased IFN gamma secretion. Exogenous IL-1 beta, IL-2 and IL-7 increased allostimulated IFN gamma secretion, whereas decreased levels were seen in the presence of IL-6, IL-10 and granulocyte-colony-stimulating factor (G-CSF). During allorecognition IFN gamma-neutralizing antibodies decreased acute myelogenous leukaemia (AML) blast secretion of G-CSF. We conclude that (i) both CD4+ and CD8+ T cells show allostimulated cytokine secretion in response to allogeneic stimulator cells containing a dominating population of native, cytokine-secreting leukaemia blasts, and (ii) IFN gamma released during this response can modulate the function of allogeneic AML blasts.

Adult↗

In vitro effects of R-verapamil on the cytokine environment and T-lymphocyte proliferation when human T-lymphocyte activation takes place in the presence of acute myelogenous leukemia blasts.

We investigated the effects of R-verapamil on the cytokine environment and T-lymphocyte proliferation when human T-lymphocytes were activated in the presence of accessory cells containing a large population of acute myelogenous leukemia (AML) blasts (nonirradiated blasts for cytokine studies, 50 Gy irradiated blasts in proliferation studies). In the presence of AML blasts, R-verapamil inhibited interleukin 4 (IL4) and interferon-gamma (IFNgamma) release from polyclonal T-cell lines activated with the T-cell mitogen phytohemagglutinin (PHA). R-verapamil also inhibited both the proliferation and the release of IFNgamma and IL10 by normal T-cells stimulated with allogeneic peripheral blood mononuclear cells derived from AML patients. This antiproliferative effect of R-verapamil was seen in the presence of exogenous IL2 but was not observed in the presence of exogenous IL1beta or granulocyte/macrophage colony-stimulating factor GM-CSF). In addition R-verapamil inhibited the release of IL1beta and tumor necrosis factor alpha during allogeneic stimulation.

Adult↗

Effects of endogenous interleukin 1 on blast cells derived from acute myelogenous leukemia patients.

The in vitro effects of interleukin 1 (IL1) secreted by acute myelogenous leukemia (AML) blasts (termed endogenous IL 1 secretion) were investigated. Interleukin 1-dependent AML blast functions were inhibited during in vitro culture either by IL1-specific neutralizing antibodies (anti-IL1 alpha and anti-IL1 beta) or by the IL1 receptor antagonist (IL1RA). Endogenous IL1 secretion showed a wide variation between individual patients, but despite this variation IL1 inhibition significantly decreased both spontaneous blast proliferation and spontaneous blast secretion of IL1 alpha, granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor alpha and interleukin 6. In contrast to spontaneous blast proliferation, in the presence of exogenous hematopoietic growth factors (granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, interleukin 3, tumor necrosis factor alpha, stem cell factor), IL1 inhibition caused either increased or decreased AML blast proliferation depending on the individual patient. When AML blasts were cultured with stem cell factor plus granulocyte-macrophage colony-stimulating factor, IL1 inhibition significantly increased AML blast proliferation. Thus, IL1 is important for regulation of AML blast proliferation and cytokine secretion independent of the level of endogenous IL1 secretion, but the final effect of IL1 is highly dependent on the cytokine network in the AML blast microenvironment.

Adult↗

Interleukin 1 receptor antagonist (IL1RA) in acute leukaemia: IL1RA is both secreted spontaneously by myelogenous leukaemia blasts and is a part of the acute phase reaction in patients with chemotherapy-induced leucopenia.

Blast cells derived from peripheral blood of patients with acute myelogenous leukaemia (AML) were cultured in vitro and interleukin 1 receptor antagonist (IL1RA) concentrations determined in culture supernatants. AML blasts derived from patients classified as AML-M4 and AML-M5 subtype showed an increased release of IL1RA. IL1 alpha and IL1 beta caused a similar increase in AML blast release of IL1RA, and addition of anti-IL1 antibodies decreased IL1RA release. IL1RA release from AML blasts was also increased by stem cell factor, tumour necrosis factor alpha (TNF alpha), granulocyte-macrophage colony-stimulating factor and macrophage colony-stimulating factor, whereas interleukin 3, interleukin 6, leukaemia inhibitory factor and granulocyte colony-stimulating factor did not significantly alter IL1RA release. When investigating IL1RA serum levels, serum concentrations were decreased in acute leukaemia patients with chemotherapy-induced cytopenia compared with healthy controls. Serum levels of both IL1RA as well as IL1 beta and soluble TNF alpha receptors increased when the leucopenic patients developed complicating bacterial infections.

Acute-Phase Reaction↗

Effects of hematopoietic growth factors on interleukin 6 secretion by blast cells derived from acute myelogenous leukemia patients.

Interleukin 6 (IL6) secretion by blast cells derived from peripheral blood of patients with acute myelogenous leukemia (AML) was characterized. IL6 secretion showed a wide variation both when AML blasts were cultured in medium alone and in the presence of exogenous cytokines. The level of IL6 secretion was significantly correlated to secretion of other cytokines (IL1 alpha, IL1 beta, granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor alpha). IL1 beta, granulocyte-macrophage colony-stimulating factor, macrophage colony-stimulating factor and stem cell factor increased IL6 secretion, whereas IL4 caused decreased IL6 secretion together with increased release of IL1 receptor antagonist.

Adult↗

Serum levels of adhesion molecules and cytokines in patients with acute leukaemia.

The cytokine network and the adhesion molecule system are intercellular signal pathways. The cytokine effects are modulated in vivo by soluble cytokine antagonists, whereas the cell to cell contact mediated by adhesion molecules and their ligands may be blocked by the soluble forms of the adhesion molecules. The cytokine network is important for proliferation and cytokine secretion by acute leukaemia blasts, and membrane-bound adhesion molecules are important for blast interactions with neighbouring cells of the in vivo microenvironment. Both these signal systems are operative during the period of cytopenia following intensive chemotherapy for acute leukaemia. In the present review, we discuss the influence of disease status, chemotherapy and complicating infections on serum levels of cytokines and soluble adhesion molecules in acute leukaemia patients. We have demonstrated increased serum levels of both cytokines and cytokine antagonists in acute leukaemia patients with complicating bacterial infections during chemotherapy-induced cytopenia. Serum levels of the selectin adhesion molecules were decreased during bacterial infections in leukopenic patients compared to healthy individuals. In contrast, the intercellular adhesion molecule-1 response and the cytokine/cytokine antagonist responses were qualitatively similar to responses seen in previously healthy individuals with serious bacterial infections.

Acute Disease↗

Effects of interleukin-13 on cytokine secretion by human acute myelogenous leukemia blasts.

Blast cells derived from patients with acute myelogenous leukemia (AML) were cultured in the presence of interleukin-13 (IL-13). IL-13 did not cause statistically significant alterations of AML blast proliferation when cells were cultured in medium alone or together with IL-4, granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor. In contrast, IL-13 inhibited constitutive AML blast secretion of IL-1 alpha, IL-1 beta, IL-6, tumor necrosis factor alpha, granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor. IL-4 caused a similar inhibition of constitutive cytokine secretion as IL-13, but IL-13 caused no additive inhibition in the presence of IL-4. In contrast to IL-4 which increased AML blast release of IL-1 receptor antagonist, IL-13 caused no significant alteration of blast release of the receptor antagonist. IL-13 inhibited cytokine secretion also in the presence of neutralizing IL-4 and IL-10 antibodies and when AML blasts were cultures in serum-free conditions. We conclude that IL-13 has a direct and nontoxic inhibitory effect on constitutive AML blast cytokine secretion.

Aged↗

In vitro effect of r-verapamil on acute myelogenous leukemia blast cells: studies of cytokine secretion and cytokine-dependent blast proliferation.

The in vitro effect of the dextroisomer r-verapamil on blast cells derived from patients with acute myelogenous leukemia (AML) was studied. R-verapamil caused a dose-dependent inhibition of AML blast proliferation in the presence of stem-cell factor, leukemia inhibitory factor, interleukin 4, interleukin 6, and interleukin 10 when these cytokines were tested both alone and in different combinations. R-verapamil also inhibited the growth of clonogenic AML blast cells. The antiproliferative effect was not specific for AML blast cells, because r-verapamil also inhibited cytokine-dependent proliferation of blast cells derived from patients with acute lymphoblastic leukemia. The inhibitory effects of r-verapamil and anti-IL1 serum were additive, suggesting that the antiproliferative effect of r-verapamil does not depend solely on inhibition of IL1-mediated effects. Although r-verapamil inhibited spontaneous AML blast proliferation, for a majority of patients it caused only minimal, if any, inhibition of spontaneous cytokine secretion (IL1 alpha, IL1 beta, TNF alpha, IL6) by AML blast cells. Thus, although inhibition of IL1 effects may contribute in certain patients to the antiproliferative effect of r-verapamil, mechanisms other than IL1 inhibition seem to be more important in mediating the effects of r-verapamil.

Adolescent↗

Cytokine modulation of interleukin 1 and tumour necrosis factor-alpha secretion from acute myelogenous leukaemia blast cells in vitro.

Spontaneous secretion of interleukin 1 (IL-1) alpha, IL-1 beta and tumour necrosis factor-alpha (TNF-alpha) from acute myelogenous leukaemia (AML) blasts showed significant correlation, and detectable levels of all cytokines were seen for a majority of patients. IL-3 and granulocyte/macrophage colony-stimulating factor increased secretion of IL-1 alpha, IL-1 beta and TNF-alpha for a majority of AML patients, whereas IL-4 decreased cytokine secretion. The effect of IL-6 and stem cell factor on cytokine secretion varied between different patients. A wide variation in IL-1 alpha, IL-1 beta and TNF-alpha secretion between different patients was seen both for spontaneous secretion and in the presence of all cytokines.

Adult↗

Serum concentrations of E-selectin, P-selectin, ICAM-1 and interleukin 6 in acute leukaemia patients with chemotherapy-induced leucopenia and bacterial infections.

Serum concentrations of E-selectin (CD62E), P-selectin (CD62P), ICAM-1 (CD54) and interleukin 6 were investigated in acute leukaemia patients with chemotherapy-induced leucopenia and complicating bacterial infections. Serum concentrations of both E-selectin and P-selectin were decreased in the leucopenic patients without infections when compared with levels before chemotherapy; and serum concentrations of both E-selectin and P-selectin showed a further decrease during complicating bacterial infections. In contrast to the leukaemia patients, previously healthy individuals with meningococcal disease showed markedly elevated serum concentrations of E-selectin and normal levels of P-selectin during infection. Serum concentrations of ICAM-1 and interleukin 6 increased during bacterial infections in the acute leukaemia patients with chemotherapy-induced leucopenia. The alterations in serum concentrations of soluble adhesion molecules and interleukin 6 reversed when clinical signs of bacterial infections resolved during antibiotic therapy. Our results demonstrate that acute leukaemia patients with chemotherapy-induced cytopenia show altered levels of both soluble adhesion molecules and interleukin 6 during complicating bacterial infections.

Adolescent↗

Secretion of leukaemia inhibitory factor after allogeneic bone marrow transplantation: a study of CD4+ and CD8+ TCR alpha beta+ T-cell clones derived from four leukaemia patients.

CD4+ and CD8+ TCR alpha beta+ T-cell clones were derived from 4 leukaemia patients early (4-6 weeks) after allogeneic bone marrow transplantation. Leukemia inhibitory factor (LIF) secretion in response to the activation signal accessory cells (AC) + phytohaemagglutinin (PHA) was investigated for each individual clone. Only a minority of CD4+ TCR alpha beta+ T-cell clones secreted LIF in response to AC + PHA, whereas most T-cell clones were capable of LIF secretion when exogenous interleukin 2 was added together with AC + PHA. LIF secretion could also be demonstrated for CD8+ TCR alpha beta+ posttransplant T-cell clones. Thus, posttransplant CD4+ and CD8+ TCR alpha beta+ clonogenic T-cells are capable of LIF secretion, and LIF secretion may be a T-cell effector mechanism in graft versus host disease, graft versus leukaemia effects or posttransplant haematopoietic reconstitution.

Bone Marrow Transplantation↗

Relative roles of natural killer- and T cell-mediated anti-leukemia effects in chronic myelogenous leukemia patients treated with interferon-alpha.

Potential anti-leukemia effects mediated by T cells or by natural killer (NK) cells were investigated in chronic myelogenous leukemia (CML) patients treated with interferon-alpha. Therapy-associated modulation of T cell and NK reactivity was monitored for one year from initiation in autologous mixed lymphocyte-tumor cell reactions and cytotoxicity directed against autologous CML cells, respectively. During the course of IFN-therapy, NK activity against autologous CML cells increased steadily, whereas T cell reactivity fluctuated randomly. Despite the high level of T cell reactivity to autologous tumor cells in short-term (6 days) culture, 1) they failed to respond to synthetic peptides corresponding to the bcr/abl fusion sequence of the patient, and 2) only one proliferative T cell clone (TCC) was isolated which specifically recognized HLA-DR-matched CML cells. This TCC appeared not to recognize synthetic peptides corresponding to the bcr/abl fusion sequence of the patient; the antigen to which it responds remains unknown. To assess potential immunogenicity of bcr/abl peptides, it was attempted to sensitize T cells from normal donors in vitro. Of 109 cell lines obtained from seven different donors, eleven showed peptide-dependent proliferation. Therefore, although these results show that it is possible to isolate apparently CML-specific T cells from patients, as well as to prime T cells against tumor-specific peptide in vitro, the frequency of such T cell-mediated reactivity appears low and its relevance to anti-leukemic effects questionable. On the other hand, the strong time-dependent enhancement of natural killing of autologous CML blasts during IFN-alpha treatment, a phenomenon not observed for T cell reactivity, suggests that natural immunity may be more important in controlling disease.

Amino Acid Sequence↗

Effects of interleukin 10 on blast cells derived from patients with acute myelogenous leukemia.

The effect of interleukin 10 (IL-10) on proliferation and cytokine secretion by acute myelogenous leukemia (AML) blast cells was investigated in vitro. IL-10 inhibited spontaneous AML blast proliferation for a majority of patients, whereas in the presence of exogenous growth factors (granulocyte-stimulating factor, G-CSF; granulocyte-macrophage colony-stimulating factor, GM-CSF; interleukin 3) the IL-10 effect on blast proliferation showed a wide variation depending on the individual AML patient. IL-10 seemed to cause an irreversible inhibitory effect on AML blasts, as inhibition could also be demonstrated when IL-10 was present only during the initial preincubation of the leukemia cells. IL-10 also inhibited AML blast colony formation. However, independent of the effect on AML blast proliferation, IL-10 decrease cytokine secretion from AML blast cells for all patients, as demonstrated for IL-1 alpha, IL-1 beta, tumor necrosis factor-alpha, GM-CSF and interleukin 6. IL-10 did not inhibit development of apoptosis in AML blasts cultured in vitro. Expression of complement receptors and capability to adhere and internalize bacteria by AML blasts were not altered by IL-10.

Aged↗