Acute-phase response in patients given rhIL-3 after chemotherapy.
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Biomedical subjects
Publications and source records attributed to A Khwaja.
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Exposure of neutrophils to a range of cytokines augments their response to subsequent agonist-induced activation of the respiratory burst. We have examined the effects of several of these factors, both singly and in combination, on the priming of f-met-leu-phe (FMLP) and complement C5a-stimulated neutrophil H2O2 production, using a whole blood flow cytometric assay designed to minimize artefactual activation. Both granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor alpha (TNF alpha) produced a similar degree of priming of the FMLP-stimulated burst in vitro (558% +/- 86%, n = 41, and 581% +/- 95%, n = 21, of the response seen with FMLP alone, respectively), but with markedly different kinetics (half-maximal response 20 minutes and 7 minutes, respectively). Preincubation with granulocyte colony-stimulating factor (G-CSF) alone caused only modest priming (202% +/- 39%, n = 14). Priming with cytokine combinations of the FMLP-stimulated burst showed that the combinations of G-CSF and TNF alpha and GM-CSF and TNF alpha are highly synergistic, with recruitment of neutrophils unresponsive to priming by single agents. Priming with the combination of GM-CSF and G-CSF was not significantly different to priming with GM-CSF alone. Similar results were obtained using C5a as the respiratory burst stimulus. Significant priming of the FMLP-stimulated respiratory burst was seen in vivo in patients receiving an infusion of GM-CSF (332% +/- 50% of preinfusion response to FMLP, P less than .005, n = 8). Priming was also seen in patients receiving G-CSF (152% +/- 58%, n = 5), although this did not reach conventional significance levels (.05 less than P less than .1). Although GM-CSF infusion caused priming in vivo, this was 48% less than predicted by preinfusion in vitro responses. This result was not due to inadequate GM-CSF levels as addition of further GM-CSF ex vivo did not correct the response. However, these neutrophils were still able to respond appropriately to ex vivo priming with TNF alpha, with a doubling in H2O2 production.
Granulocyte-macrophage colony-stimulating factor (GM-CSF) is active in enhancing the production of mature myeloid cells in vitro and several phase I/II clinical trials have suggested that its administration may accelerate neutrophil recovery after autologous bone marrow transplantation (ABMT). We have conducted a multicentre randomized double-blind placebo controlled trial in patients with poor prognosis malignant lymphoma receiving an identical high-dose combination chemotherapy regimen with ABMT. 61 patients were entered and 29 in each arm of the trial were evaluated. Treatment with GM-CSF did not affect the period of severe neutropenia (absolute neutrophil count (ANC) of < 0.1 x 10(9)/l) but accelerated recovery to an ANC of 0.5 x 10(9)/l (median 14 d v 20 d in controls, P = 0.001). There was no significant difference in platelet recovery between the groups (GM-CSF group platelet dependent for 25 d v control 19 d, P = NS). The number of positive blood cultures was similar in both groups (GM-CSF 14 v placebo 13) and there were no differences in days of fever > 37.5 degrees C (median 8 v 6) or days on parenteral antibiotics (11 v 10). Patients receiving GM-CSF had a median period of hospitalization following BMT of 24 d (control 25). No significant major toxicity attributable to GM-CSF administration was detected. We have confirmed in a randomized trial that GM-CSF accelerates neutrophil but not platelet recovery following ABMT. We were unable to demonstrate any accompanying changes in clinical outcome and believe that further trials are necessary to assess the clinical value of GM-CSF in BMT.
Macrophage colony-stimulating factor (M-CSF) is active in the late stages of monocyte maturation, activates mature monocyte-macrophages and enhances their production of various other cytokines. We have examined the effects of a 21 d course of escalating doses of M-CSF purified from human urine (hM-CSF) on recovery following autologous bone marrow transplantation (ABMT) in 20 patients with malignant lymphomas. Four patients were treated at each dose level of 4, 8, 16, 32 and 64 x 10(6) U/m2/d and results compared to 46 concurrent controls. There was no significant difference in recovery to an absolute neutrophil count (ANC) of 0.5 x 10(9)/l (median 20 d in hM-CSF group versus 22 in controls) or in recovery of platelets to 50 x 10(9)/l (32 d versus 39 d, 0.05 less than P less than 0.1); hM-CSF patients received a median of 81 platelet units following ABMT (controls 112 units, P = NS). hM-CSF patients had a median of 5.5 d with fever greater than 37.5 degrees C (control 8, P = NS), received parenteral antibiotics for 14.5 d (control 17, P = NS) and had a 50% incidence of bacteraemia (control 48%). hM-CSF treated patients were discharged by a median of day 29 following transplantation (control 33, P less than 0.05). Platelet and neutrophil recovery correlated significantly with the number of marrow mononuclear cells (MNC) reinfused in the hM-CSF group (P = 0.05 and P = 0.014 respectively) but not in controls. Subgroup analysis showed that hM-CSF patients receiving greater than 2 x 10(8) MNC/kg body weight reached an ANC of 0.5 x 10(9)/l by a median of day 16.5 (control 18.5, NS), became platelet transfusion independent by day 17 (control 29, P less than 0.05) and reached a platelet count of 50 x 10(9)/l by day 21 (control 40, P less than 0.05). No significant toxicity attributable to hM-CSF treatment was seen. These results suggest that hM-CSF accelerates platelet recovery following ABMT and that relatively large marrow innocula are required to see this effect.
The Wellcome Tropical Institute has assisted countries in the tropics to establish viable systems of continuing medical education, particularly for young doctors practising in rural areas. As part of this strategy the Institute has developed material for use in distance learning. The first attempt to apply the problem-based learning approach to written material for use by an individual learner in the absence of a tutor led to a trial in Ghana, Kenya and Pakistan to compare a conventionally designed module with a problem-based learning module on the same topic for their respective acceptability, effectiveness and efficiency. The design, implementation and results of these three comparative trials are presented.
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The hematopoietic growth factors, granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF), enhance the effector functions of mature myeloid cells, including the interaction with vascular endothelium. We examined the direct effect of recombinant human GM-CSF (rhGM-CSF) and recombinant human G-CSF (rhG-CSF) on the growth and function of cultured human umbilical vein endothelial cells (HUVEC). Endothelial cell growth supplement (ECGS) increased the proliferation of passaged and primary cells by 305% +/- 45% (mean +/- SEM, n = 5, P less than .01) over control cells at 4 days; GM-CSF and G-CSF had no effect. Endothelial cell procoagulant activity was increased after 4-hour incubation with recombinant interleukin-1 beta (IL-1 beta) 10 U/mL and recombinant tumor necrosis factor (TNF) 10 U/mL to 1,721% +/- 376% (n = 7, P less than .005) and 247% +/- 71% (n = 4) of control levels, respectively. gamma-Interferon (gamma-IFN) 50 U/mL had no direct effect of its own but was able to prime the response to IL-1 beta. There was no direct or priming effect of GM-CSF (1 ng to 1 microgram/mL) on the expression of procoagulant activity in endothelial cells. GM-CSF and G-CSF (1 ng/mL to 1 microgram/mL) had no effect on the expression of either tissue plasminogen activator (tPA) or plasminogen activator inhibitor-1 (PAI-1) by endothelial cells. The secretion of tPA by endothelial cells was increased, however, after 24-hour incubation with thrombin 4 U/mL (314% +/- 72% of control levels, n = 5, P less than .025). The production of PAI-1 was increased by TNF 200 U/mL (241% +/- 44% of control, n = 3, P less than .005), thrombin 4 U/mL (180% +/- 12% of control, n = 5, P less than .0005) and IL-1 beta 10 U/mL (275% +/- 44% of controls, n = 5, P less than .0005). In four experiments, endothelial cells showed no specific binding of 125I-GM-CSF, whereas peripheral blood (PB) neutrophils demonstrated the presence of 802 +/- 78 high-affinity receptors for GM-CSF. Thus, we found no effect of rhGM-CSF or rhG-CSF on the proliferation activities by these cells. These findings are in accordance with the lack of demonstrable receptors for GM-CSF on cultured HUVEC.
Macrophage colony-stimulating factor (M-CSF) is reported to enhance a variety of functions of mature monocyte/macrophages in vitro. We have examined the effects of a 2 h intravenous infusion of M-CSF obtained from human urine (hM-CSF) on haematological parameters and selected monocyte functions. There was a rapid, small, but consistent reduction in Hb concentration (mean 6.5 +/- 2.3%, P less than 0.0005 by paired t test) by the completion of the hM-CSF infusion and small, transient falls in platelet, monocyte and neutrophil counts were noted in the 2 h following the end of the infusion. No effect on monocyte or neutrophil CD11b cellular adhesion molecule expression was detected. Exposure to hM-CSF in vivo did not directly stimulate the monocyte respiratory burst, but increased the percentage of monocytes responding to f-met-leu-phe from 9.8 +/- 2.5 to 16.6 +/- 4.2 (P less than 0.01). The number of candida ingested and degraded per 100 monocytes increased from 101 +/- 14 pre-infusion to 160 +/- 22 post-infusion (P less than 0.01). There was a rapid increase in the numbers of monocytes entering a skin window membrane from a mean of 226 +/- 71 pre-infusion to 1064 +/- 404 at the end of the infusion, with no effect on neutrophil migration. These data show that the administration of hM-CSF enhances several of the functions of peripheral blood monocytes in vivo, and this may be of benefit in the treatment of selected infections.
Human granulocyte-macrophage colony-stimulating factor (GM-CSF) increases neutrophil surface expression of the cellular adhesion molecule CD11b and primes the respiratory burst stimulated by the bacterial peptide f-met-leuphe (FMLP). We have examined the effects of the isoquinolinesulfonamide protein kinase inhibitors H7 and H8 on these functions of GM-CSF using whole blood assays. Concentrations of H7 and H8 that inhibited the 12-O-tetradecanoyl-phorbol-13-acetate (TPA) stimulated upregulation of CD11b expression and activation of the respiratory burst, both augmented the effects of GM-CSF. H7 and H8 enhanced the GM-CSF-stimulated increase in CD11b expression to 215% +/- 10% (P less than .05) and 233% +/- 45% (P less than .05), respectively, of the value obtained with GM-CSF alone. The GM-CSF priming of the FMLP-stimulated oxidative burst was increased to 190% +/- 44% (P less than .01) by preincubation with H7 and to 172% +/- 25% (P less than .01) with H8. Preincubation with H8 did not affect overall binding of 125I-GM-CSF to neutrophils, but inhibited GM-CSF receptor internalization after ligand binding (P less than .05). These data indicate that the effects of GM-CSF are not mediated by protein kinase C and that a phosphorylation event down-modulates the neutrophil response to GM-CSF. It suggests that internalization of the receptor-ligand complex is not a rate-limiting step in signal transduction, and that regulation of the rate of internalization may be an important level of control of the activity of GM-CSF.
The availability of recombinant haemopoietic growth factors for clinical use has led to a proliferation of trials in the setting of bone marrow transplantation. Early results from these studies, using GM-CSF and G-CSF, show that these factors are able to reduce the period of cytotoxic induced neutropaenia but have little effect on platelet recovery. Toxicity has been relatively mild unless very high doses are administered. Randomised controlled trials are in progress and will help to define the exact role of growth factors in this setting. Future prospects include the increasing availability of other growth factors for clinical use and the potential for combination growth factor therapy to provide a more optimal haemopoietic response.
Leucocytes express adhesion promoting receptors which mediate cell-cell and cell-matrix interactions. These adhesive interactions are crucial to the regulation of haemopoiesis and thymocyte maturation, the direction and control of leucocyte traffic and migration through tissues, and in the development of immune and non-immune inflammatory responses. Several families of adhesion receptors have been identified (Table). The leucocyte integrin family comprises 3 alpha beta heterodimeric membrane glycoproteins which share a common beta subunit, designated CD18. The alpha subunits of each of the 3 members, lymphocyte function associated antigen-1 (LFA-1), macrophage antigen-1 (Mac-1) and p150,95 are designated CD11a, b and c respectively. These adhesion molecules play a critical part in the immune and inflammatory responses of leucocytes. The leucocyte integrin family is, in turn, part of the integrin superfamily, members of which are evolutionally, structurally and functionally related. Another Integrin subfamily found on leucocytes is the VLA group, so-called because the 'very late activation antigens' VLA-1 and VLA-2 were originally found to appear late in T-cell activation. Members of this family function mainly as extracellular matrix adhesion receptors and are found both on haemopoietic and non-haemopoietic cells. They play a part in diverse cellular functions including tissue organisation, lymphocyte recirculation and T-cell immune responses. A third integrin subfamily, the cytoadhesins, are receptors on platelets and endothelial cells which bind extracellular matrix proteins. A second family of adhesion receptors is the immunoglobulin superfamily, members of which include CD2, LFA-3 and ICAM-1, which participate in T-cell adhesive interactions, and the antigen-specific receptors of T and B cells, CD4, CD8 and the MHC Class I and II molecules. A recently recognised family of adhesion receptors is the selectins, characterised by a common lectin domain. Leucocyte adhesion molecule-1 (LAM-1), which is the human homologue of the murine homing receptor, MEL-14, is expressed on leucocytes, while endothelial leucocyte adhesion molecule-1 (ELAM-1) and granule membrane protein (GMP-140) are expressed on stimulated endothelial cells and activated platelets. This review will be confined to adhesion receptors found on leucocytes, with particular emphasis on the leucocyte integrins.
A simple semiquantitative cytofluorometric method has been developed for measuring neutrophil respiratory burst activity in whole blood samples. This technique avoids the introduction of laboratory artefacts which modulate neutrophil function. In addition, flow cytometric analysis allows the response to be studied in individual cells. We show here that neutrophils examined freshly ex vivo, exhibit only weak respiratory burst activity in response to stimulation with the chemotactic peptide FMLP (10(-6) M). Prior incubation with rhGM-CSF results in an increase in the number of responding cells from 13.5 +/- 2.36% (mean +/- SEM) to 46.7 +/- 6.3% (P less than 0.0001) with an increase in total respiratory burst activity of 567% (P = 0.001). The majority of neutrophils in whole blood (67.1 +/- 8.1%) exhibit respiratory burst activity in response to stimulation with phorbol ester (1 micrograms/ml of TPA), and this response is also significantly primed by rhGM-CSF (P = 0.004). The enhancement of respiratory burst activity induced by rhGM-CSF is due to both recruitment of previously unresponsive neutrophils, and to intensification of the response of the responding cells. In vivo administration of rhGM-CSF also results in priming of the respiratory burst in response to FMLP, although the enhancement of activity is not as great as that obtained when pre-infusion blood samples are incubated with rhGM-CSF in vitro.