leukotriene-b4 and Leukemia--Myelogenous--Chronic--BCR-ABL-Positive

Binding of chemoattractant to polymorphonuclear leukocytes (PMNL) triggers a series of events like polymerization of actin and tubulin, orientation of cells, chemotaxis, increase in fluid pinocytosis and phagocytosis, and stimulation of microbicidal pathways which includes lysosomal degranulation and generation of reactive oxygen species. Earlier studies from our laboratory have shown that stimulation of chemotaxis, fluid pinocytosis, and actin polymerization of CML PMNL in response to a synthetic chemotactic peptide formyl-methionyl-leucyl-phenylalanine (fMLP) is significantly lower than that in normal PMNL. It is not known whether this lower response of CML PMNL to fMLP is a global phenomenon involving different chemoattractant receptors or is restricted to the fMLP pathway. We have evaluated chemoattractant induced degranulation process in normal and CML PMNL to fMLP, platelet activating factor (PAF), leukotriene B4 (LTB4), and an analogue of fMLP viz formyl-methionine-1 aminocyclooctane 1 carboxylic acid-phenylalanine-O-methionine (FACC8) using release of lysozyme as a parameter. We find that after stimulation with fMLP and FACC8, the mean percent release of lysozyme was significantly lower in CML PMNL as compared to that in normal cells (P < 0.001). There was no significant difference between the two after stimulation with PAF and LTB4. The results indicate that the fMLP pathway is suppressed in CML granulocytes whereas PAF and LTB4 pathways appear unaltered in these cells. We therefore also studied the kinetics of peptide-receptor interaction with a labelled hexapeptide fNLPNTL which binds to the fMLP receptor. Our results show that the number of fMLP receptors/cell is significantly lower in CML PMNL (P < 0.05) than in normal PMNL, while their affinity constants and dissociation constants were comparable.

Topics: Chemotactic Factors; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukotriene B4; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Oligopeptides; Platelet Activating Factor; Receptors, Formyl Peptide; Receptors, Immunologic; Receptors, Peptide; Reference Values

This study focuses on possible functional defects of circulating mature neutrophils in chronic phase chronic myelogenous leukemia (CML) and their modulation by interferon-alpha (IFN-alpha). Polymorphonuclear cells (PMN) of seven untreated and nine IFN-alpha-treated patients were evaluated for the following parameters by the following methods: generation of oxygen species, by luminol-dependent chemiluminescence; leukotriene B4 (LTB4) generation, by high-performance liquid chromatography (HPLC); expression of LTB4 and formylmethionyl-leucyl phenylalanine (FMLP) receptor sites, by 3H-binding assay; and GTPase activity, by 32P-gamma-GTP. Compared to normal controls, reduced values were obtained in treated and untreated CML for most parameters studied. Therapy with IFN-alpha resulted in significantly diminished values for oxygen species (NaF stimulation) and LTB4 (FMLP stimulation) generation, as well as FMLP receptor expression as compared to untreated CML. We conclude that alterations at the level of oxygen species production, mediator generation, receptor expression, and transmembrane signaling are involved in functional defects of circulating mature neutrophils from CML patients. IFN-alpha seems to enhance some of these functional defects, but the clinical relevance of these findings has be elucidated.

Topics: Adult; Aged; Cell Membrane; Chromatography, High Pressure Liquid; Female; GTP Phosphohydrolases; GTP-Binding Proteins; Humans; Interferon-alpha; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukotriene B4; Luminescent Measurements; Luminol; Male; Middle Aged; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Reactive Oxygen Species; Receptors, Formyl Peptide; Receptors, Immunologic; Receptors, Leukotriene; Receptors, Peptide; Signal Transduction

A sensitive gas chromatography-mass spectrometric method was used to measure the generation in whole blood of leukotriene B4 (LTB4), a potent stimulator of neutrophil chemotaxis, in eight patients with chronic granulocytic leukaemia (CGL) and 12 healthy controls. LTB4 was detectable in unstimulated samples from all the patients (mean 194 (70 SEM) pg/ml), and the capacity for LTB4 production after stimulation with calcium ionophore (A23187) was similar in patients (32.1 (11) ng/10(6) leucocytes) and controls (38.1 (4) ng/10(6) leucocytes). In response to stimuli which induce neutrophil activation, LTB4 production was significantly greater in the patients than in controls: 35.6 (13) v 13.0 (3) ng/ml, p less than 0.05 (f-met-leu-phe); and 42.4 (16) v 14.7 (4) ng/ml, p less than 0.02 (opsonised zymosan). Anti-IgE stimulated considerably more LTB4 production in patients with CGL than in controls (3.86 (1.6) v 0.83 (0.43) ng/ml; p less than 0.005) and this correlated significantly (p less than 0.05) with the basophil count. Neutrophil chemotaxis to LTB4, however, was significantly impaired in the patients with CGL even at the highest concentration of LTB4 (10(-5) M). Chemotaxis to f-met-leu-phe, phagocytosis, and bacterial killing were normal. Thus although LTB4 synthesis is normal or even enhanced in patients with CGL, specific defects in LTB4-mediated responses may contribute to neutrophil dysfunction in this disease.

Topics: Adult; Aged; Antibodies, Anti-Idiotypic; Calcimycin; Chemotaxis, Leukocyte; Humans; Immunoglobulin E; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukotriene B4; Male; Middle Aged; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Phagocytosis

The production of leukotrienes (LT) in peripheral blood leukocyte preparations from 9 patients with chronic myelogenous leukemia (CML) and 9 healthy controls was studied. Leukotriene generation was stimulated by the calcium ionophore A 23187 (1 mumol). Lipoxygenase products were separated and identified using a high performance liquid chromatography (HPLC) technique and computerized spectrophotometry. Leukotriene C4 (LTC4) was formed in significantly larger amounts by cells from the CML patients than cells from the controls; 14.4 +/- 4.3 pmol per 10(6) nucleated cells (mean +/- SE) and 4.0 +/- 1.2 pmol respectively (p less than 0.05). Seven of the 9 patients but none of the controls synthesized equal or higher amounts of LTC4 than LTB4. A highly significant difference in mean values of LTC4/(LTB4 + 20-OH-LTB4) ratios was observed; CML 0.69 +/- 0.08 versus controls 0.12 +/- 0.02, p less than 0.001. These findings suggest an increased LTC4 synthase activity in CML cells. In earlier studies we have found a decreased 12-lipoxygenase activity in CML bone marrow cells.

Topics: Calcimycin; Humans; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukocytes; Leukotriene B4; SRS-A