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W Luttmann

Publications and source records attributed to W Luttmann.

At least 37 records · Page 2Linked to original sources
PubMed1999

Synergistic effects of interleukin-4 or interleukin-13 and tumor necrosis factor-alpha on eosinophil activation in vitro.

Increased concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-4, and IL-13 have been measured in bronchoalveolar lavage fluid (BALF) of patients with asthma following allergen provocation. In addition, these cytokines have also been reported to activate eosinophils in vitro. Although cytokine interactions have been postulated in the activation of eosinophils, the combined effects of cytokines on eosinophil activation remain poorly understood. Because activation of eosinophils has been regarded as a crucial event in the pathogenesis of asthmatic inflammation, we tested the hypothesis that IL-4 and IL-13 could enhance the effects of TNF-alpha on eosinophil activation. For this purpose, eosinophils from normal donors were purified and cultured in the presence of IL-4 or IL-13 and TNF-alpha. Eosinophil survival and surface expression of CD69 were assessed by flow cytometry. There was a concentration- and time-dependent upregulation in CD69 expression as well as eosinophil survival when eosinophils were incubated with IL-13, IL-4, or TNF-alpha. However, eosinophil viability and CD69 expression increased synergistically when eosinophils were incubated with IL-13 or IL-4 in the presence of TNF-alpha. This synergistic effect of IL-4 and IL-13 on CD69 expression was not limited to TNF-alpha but was also observed with IL-5. Our study provides evidence that IL-4 can activate eosinophils in a similar fashion as does IL-13. Furthermore, this study shows that the addition of IL-4 or IL-13 to TNF-alpha or IL-5 has synergistic effects on eosinophil activation, suggesting that the combined effects of different cytokines present in BALF following allergen provocation can enhance eosinophil activation in vitro.

Antigens, CD↗
PubMed1999

CD69 surface expression on human lung eosinophils after segmental allergen provocation.

CD69 expression on eosinophils is observed in asthma and has been proposed as a marker of eosinophil activation. The role of allergens in the in vivo regulation of CD69 expression on eosinophils, however, remains incompletely understood. It was therefore investigated whether CD69 expression on eosinophils can be induced by allergen provocation in vivo. Ten allergic asthmatics were studied by segmental allergen provocation. Two segments of the right and left lung were challenged with allergen or saline. CD69 expression was determined by flow cytometry and concentrations of interleukins were analysed by enzyme-linked immunosorbent assay in bronchoalveolar lavage (BAL) fluid. Expression of CD69 on BAL eosinophils in the segments lavaged 10 min following saline instillation (28.3+/-8.8 specific mean fluorescence (SMF)) was not significantly different to segments lavaged 10 min after allergen (80.2+/-21.8 SMF) and segments lavaged 18 h after saline challenge (87.2+/-23.3 SMF). However, CD69 expression on eosinophils increased significantly 18 h after allergen challenge (128.6+/-21.9 SMF, p<0.03) which was accompanied by elevated granulocyte-macrophage colony-stimulating factor (GM-CSF) concentrations (114.9+/-42.9 pg x mL(-1), p<0.05). CD69 expression on eosinophils and GM-CSF concentrations correlated 18 h following allergen provocation (r = 0.7, p<0.025). These results suggest that in allergic asthma there is an allergen dependent, endobronchial upregulation of eosinophil activation as assessed by CD69 expression on eosinophils.

Adult↗
PubMed1999

Leukocyte infiltration and secretion of cytokines in pleural drainage fluid after thoracic surgery: impaired cytokine response in malignancy and postoperative complications.

STUDY OBJECTIVE: To assess the postoperative course of pleural leukocyte counts and cytokine concentrations in patients with malignant and nonmalignant lung disease who underwent thoracic surgery. PATIENTS AND INTERVENTIONS: A total of 21 patients undergoing thoracic surgery were included in the study. Twelve patients had a malignant disease, and 9 had a nonmalignant disease. Six patients underwent video-assisted thoracoscopy and 15 underwent thoracotomy. Pleural drainage fluid from the chest tubes was collected postoperatively at Oh, 3h, 6h, 12h, 24h, 48h, 72h, and 96 h. The same schedule, as well as one additional preoperative sample, was applied for blood collections. RESULTS: A trend toward lower concentrations of tumor necrosis factor-alpha (TNF-alpha), granulocytemacrophage colony-stimulating factor, and interleukin-10 was observed in patients with malignant disease compared to those without malignancy. These differences achieved significance for TNF-alpha in the drainage fluid of those patients with nonmalignant disease who had undergone formal thoracotomy. Patients with malignant disease showed significantly lower macrophage fractions in drainage fluid and lymphocyte fractions in serum. All patients with complications had malignant disease and showed the lowest cytokine concentrations, as well as the lowest fractions of both macrophages in drainage fluid and lymphocytes in serum. CONCLUSION: The data suggest that malignancy may lead to impairment of the wound-healing process via modification of the inflammatory cell infiltrate and locally released cytokines.

Adult↗
PubMed1998

Differential regulation of CD95 (Fas/APO-1) expression in human blood eosinophils.

CD95 (Fas, APO-1) is a cell surface receptor expressed on many cells including eosinophils which mediates apoptosis when ligated by agonistic antibodies or its natural ligand FasL. Since inhibition of apoptosis may play an important role in controlling tissue eosinophilia, we investigated the expression of CD95 on purified peripheral blood eosinophils from normal donors. Freshly isolated eosinophils expressed CD95 on the cell surface as well as CD95-specific mRNA at low levels which did not change during 24-h culture. Incubation of eosinophils with IL-3, IL-5 and granulocyte-macrophage colony-stimulating factor (GM-CSF) did not modulate the basal expression of CD95. IFN-gamma as well as TNF-alpha, however, induced a significant, dose- and time-dependent increase in CD95 mRNA and cell surface expression as measured by reverse transcription-PCR and flow cytometry. Co-stimulation with IFN-gamma and TNF-alpha had synergistic effects on the CD95 surface expression on eosinophils. Addition of IL-3, IL-5 or GM-CSF to IFN-gamma- and TNF-alpha-stimulated eosinophils caused in a reduction of CD95 expression. Functional activity for CD95 following incubation with IFN-gamma and TNF-alpha was demonstrated by increased apoptosis in response to cross-linking with FasL. From these data, we conclude that IFN-gamma and TNF-alpha can up-regulate cell surface expression of CD95 on eosinophils, which leads to an increased susceptibility of eosinophils to Fas-mediated apoptosis. Thus, our results suggest that receptors involved in eosinophil apoptosis can be regulated by antagonistic cytokines.

Apoptosis↗
PubMed1998

Effects of TGF-beta on eosinophil chemotaxis.

Transforming growth factor-beta (TGF-beta), which can decrease the effects of interleukin (IL)-3, IL-5 and granulocyte-macrophage colony-stimulating factor (GM-CSF) on eosinophil viability, has been shown to be chemotactic for neutrophils. However, there is little information on its effects on eosinophil chemotaxis. Because TGF-beta has recently been found in increased concentrations in asthmatic sputum, we investigated whether TGF-beta could influence eosinophil migration and eosinophil viability. Purified eosinophils from normal donors were incubated with increasing concentrations of TGF-beta. Chemotaxis was measured with a modified Boyden chamber technique. In addition, eosinophils were incubated for 96 h with either IL-3, IL-5 or GM-CSF (1 ng/ml) together with increasing concentrations of TGF-beta. Eosinophil viability was then determined with propidium jodide and flow cytometry. Eosinophil chemotaxis was significantly increased in the presence of TGF-beta in concentrations between 10(-9) and 10(-4) microg/ml. The optimal concentration of TGF-beta in this assay was between 10(-9) and 10(-8) microg/ml. The chemotactic effect of TGF-beta diminished when higher as well as lower concentrations (between 10[-12] and 10[-3] microg/ml) were employed. In contrast, inhibition of eosinophil survival induced by IL-3, IL-5 and GM-CSF reached its maximum at concentrations of TGF-beta between 10(-4) and 10(-3) microg/ml. From these data we conclude that TGF-beta in low concentrations can induce eosinophil chemotaxis whereas higher concentrations reduce eosinophil survival mediated by IL-3, IL-5 and GM-CSF.

Cell Survival↗
PubMed1998

Inhibition of HLA-DR expression on activated human blood eosinophils by transforming growth factor-beta1.

Peripheral blood, bronchoalveolar lavage and sputum eosinophils of patients with asthma but not peripheral blood eosinophils from normal controls have been shown to express human leucocyte antigen (HLA)-DR on their cell surface. Cytokines implicated in the activation of eosinophils, such as interleukin (IL)-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF), can up-regulate HLA-DR expression. However, little is known about antagonistic factors that might down-regulate HLA-DR expression on eosinophils. In this study we investigated whether transforming growth factor-beta (TGF-beta), which has been shown to reduce survival of activated eosinophils, can also modulate HLA-DR expression on eosinophils. For this purpose, isolated peripheral blood eosinophils were stimulated with IL-3 and GM-CSF for 24 h and HLA-DR expression was measured by flow cytometry. We found that while isolated eosinophils expressed low levels of surface HLA-DR, incubation with GM-CSF and IL-3 increased HLA-DR expression on eosinophils. TGF-beta alone did not change HLA-DR expression on isolated eosinophils. However, co-incubation of eosinophils with TGF-beta and either GM-CSF or IL-3 significantly decreased HLA-DR expression compared to eosinophils incubated with either GM-CSF or IL-3 alone and this was not reversed by addition of IL-5. This effect of TGF-beta on IL-3-induced HLA-DR expression was attenuated dose-dependently in the presence of monoclonal anti-TGF-beta antibodies. Our results suggest that TGF-beta can reduce cytokine-induced HLA-DR expression on eosinophils and could thus influence eosinophil activation.

Cells, Cultured↗
PubMed1998

Neurotrophins are increased in bronchoalveolar lavage fluid after segmental allergen provocation.

The mechanisms linking inflammation and airway hyperresponsiveness in allergic bronchial asthma are still not completely defined. Since neurotrophic factors increase nerve excitability and neurotransmitter synthesis and are produced by immunocompetent cells, they are likely candidates as mediators of inflammation and hyperresponsiveness. We tested the hypothesis that neurotrophin concentrations will increase in the bronchoalveolar lavage (BAL) fluid from patients with asthma after segmental allergen provocation. For this purpose an individually standardized dose of allergen or saline was instilled into different segments during bronchoscopy in eight subjects with mild allergic bronchial asthma. Segments were then lavaged 10 min and 18 h after allergen challenge or saline instillation. There was a significant increase in the neurotrophins nerve growth factor, brain-derived neurotrophic factor, and neurotrophin-3 in BAL fluids 18 h after allergen but not saline challenge. We conclude that neurotrophins are produced endobronchially following allergen provocation, suggesting a contribution to the pathogenesis of asthma.

Adult↗
PubMed1998

CD14 expression and soluble CD14 after segmental allergen provocation in atopic asthma.

Allergic asthma is associated with the recruitment of activated inflammatory cells after allergen challenge. Surface expression of CD14 has been proposed as a marker of cell activation and differentiation. We therefore measured CD14 expression on activated macrophages and granulocytes as well as soluble CD14 (sCD14) concentrations in peripheral blood and bronchoalveolar lavage (BAL) following segmental allergen provocation (SAP) with individually standardized doses of allergen in eight patients with allergic asthma. Two segments of the right lung were challenged with allergen. Two segments of the left lung, into which saline was instilled, served as controls. CD14 expression on macrophages and granulocytes was determined by flow-cytometry and concentrations of interleukins and sCD14 were analysed by enzyme-linked immunosorbent assay (ELISA) 10 min and 18 h after challenge. Soluble CD14 concentrations remained unchanged in BAL fluid after saline challenge and 10 min after SAP, but increased significantly 18 h after SAP. Although macrophage numbers increased 18h after SAP, CD14 expression on these cells did not change. Unlike macrophages, granulocyte numbers correlated with sCD14 levels 18 h after SAP while their CD14 expression decreased significantly. Furthermore, sCD14 correlated with interleukin (IL)-13 concentrations 18 h after SAP. An increase in soluble CD14 can be observed 18 h but not 10 min after segmental allergen provocation suggesting local release of this surface antigen. Our findings imply that CD14-mediated cell activation following segmental allergen provocation could play a role in asthmatic inflammation.

Adult↗
PubMed1996

Activation of human eosinophils by IL-13. Induction of CD69 surface antigen, its relationship to messenger RNA expression, and promotion of cellular viability.

To study the effect of IL-13 on CD69 expression and cell viability in human eosinophils, purified human peripheral blood eosinophils from healthy donors were incubated with increasing concentrations of IL-13. The expression of CD69 was analyzed by flow cytometry (FACS). Surface expression of CD69, which was absent on untreated eosinophils, was induced by IL-13 at concentrations ranging from 1 ng/ml to 1 microgram/ml in a concentration-dependent manner. In contrast, neutrophils expressed CD69 neither spontaneously nor following incubation with IL-13. Semiquantitative reverse transcription-PCR for CD69 mRNA showed constitutive CD69 mRNA expression in purified human eosinophils. Incubation of eosinophils with IL-13 further increased CD69-specific mRNA. Analysis of intracellularly stored CD69 in eosinophils permeabilized with saponin revealed intracellular binding of anti-CD69 Abs in all isolated eosinophils. After stimulation with 100 ng/ml IL-13 for 24 h, the concentration of intracellular CD69 decreased by 41 +/- 9%. Furthermore, IL-13 at a concentration of 100 ng/ml enhanced eosinophil viability, as assessed by propidium iodide staining after 4 days in culture from 8.6 +/- 5.5% in control medium to 50.7 +/- 6.8% following stimulation with IL-13 treatment. The effect of Il-13 on eosinophil viability as well as that on CD69 expression were both neutralized by anti-IL-13 Abs. In conclusion, our results demonstrate that IL-13 specifically activates human eosinophils, as determined by the expression of CD69 cell surface protein and mRNA expression. Furthermore, IL-13 significantly prolongs eosinophil survival in vitro. The data suggest that IL-13 may play a role in the activation of eosinophils.

Antigens, CD↗
PubMed1996

Prostacyclin modulates granulocyte/macrophage colony-stimulating factor release by human blood mononuclear cells.

Although production and immunological activity of granulocyte-macrophage colony stimulating factor (GM-CSF) have been implicated in the pathogenesis of various disorders, little has been reported concerning the factors involved in the regulation of GM-CSF release. Therefore, we examined the effect of the stable prostacyclin agonist, cicaprost, on the in vitro production of GM-CSF by peripheral blood mononuclear cells (PBMC) obtained from normal subjects by enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR). Incubation of PBMC (10(6) cells/ml1) with the bacterial lipopolysaccharide (LPS; 0.1 microgram/ml) for 24 h caused a more than 10-fold concentration-dependent increase of GM-CSF release (401 +/- 58 pg/ml x 10(6) cells-1). Addition of cicaprost (0.01 ng/ml to 1 microgram/ml) resulted in a concentration- and time-dependent reduction of LPS-induced GM-CSF secretion by PBMC with a mean IC50 of 6.7 ng/ml (n = 9). Furthermore, cicaprost also inhibited the LPS-elicited expression of GM-CSF mRNA, as determined by RT-PCR. These results demonstrate that prostacyclin inhibits LPS-induced GM-CSF release and that its effects are related to the level of transcription. Hence, our data suggest that cicaprost or related PGI2 agonists may represent immunomodulators of mononuclear cell function and may offer a therapeutic approach to GM-CSF-mediated inflammatory disorders.

Epoprostenol↗
PubMed1996

Endobronchial secretion of interleukin-13 following local allergen challenge in atopic asthma: relationship to interleukin-4 and eosinophil counts.

We investigated the secretion of interleukin (IL)-13 into the airways in 10 mild allergic asthmatics by employing local allergen challenge, and compared the data both to IL-4 levels and eosinophil numbers obtained by bronchoalveolar lavage (BAL). Appropriate allergen or saline were endoscopically instilled into different airway segments, which were lavaged 10 min and 18 h after allergen or sham challenge. IL-4 and IL-13 were measured in unconcentrated BAL fluid using a double sandwich enzymes-linked immunosorbent assay (ELISA). Endobronchial allergen challenge induced a highly significant increase in the numbers of eosinophils after 18 h in the allergen exposed segment. Ten minutes following allergen exposure, low levels of IL-4 and IL-13 could be detected, whilst concentrations of both cytokines were significantly raised 18 h following local allergen exposure. In contrast to IL-4, the concentration of IL-13 strongly correlated with the eosinophil numbers found 18 h post-allergen challenge. The results suggest that interleukin-13 is actively secreted during the late asthmatic response in mild asthmatic subjects. In view of its action on eosinophils and other cell types, we conclude that interleukin-13, in addition to interleukin-4, may play an important role in the pathogenesis of eosinophil-related inflammation, such as bronchial asthma.

Adult↗
PubMed1996

Adherence of neutrophils to human peritoneal mesothelial cells: role of intercellular adhesion molecule-1.

Peritonitis is accompanied by a massive influx of polymorphonuclear leukocytes (PMN) into the peritoneal cavity, little is known, however, about the process of neutrophil transmigration across the peritoneal membrane. The study presented here, therefore, investigates the adherence of human PMN to human peritoneal mesothelial cell monolayers and examines the importance of intercellular adhesion molecule-1 (ICAM-1) in the process. Human peritoneal mesothelial cells (HPMC) constitutively expressed ICAM-1 protein and mRNA. Stimulation with IL-1 beta or TNF alpha resulted in time- and dose-dependent upregulation of ICAM-1 mRNA transcript and increased cell-surface immunoreactive protein expression. Peak surface expression of ICAM-1 occurred between 12 and 24 h after cytokine stimulation when the level of expression was increased by on average threefold above control. The adherence of PMN to HPMC after stimulation with either IL-1 beta or TNF alpha was both dose- and time-dependent. Peaks of PMN binding to HPMC occurred at 2 and 12 h after stimulation. After 12 h, the number of PMN binding to HPMC increased from 71.3 +/- 12.5 in control cells to 180 +/- 36.5 and 125 +/- 23.6 (x 10(3) PMN), after IL-1 beta (100 pg/mL) and TNF alpha (1000 pg/mL), respectively (z = 2.52 and 2.38, N = 6, P < 0.02 versus control for both). The roles of HPMC ICAM-1 and the PMN counter receptor LFA-1 (CD11a/CD18) in the adherence of PMN to HPMC were confirmed by using anti-CAM Fab2' fragments, and anti-integrin antibodies, all of which significantly reduced the adherence of PMN to both control and cytokine-treated HPMC. These data suggest that ICAM-1 expression by HPMC may be one mechanism by which neutrophils adhere to the mesothelium during their transmigration into the inflamed peritoneal cavity.

Antigens, CD↗
PubMed1995

[Immunopathogenesis of allergic bronchial asthma. Detection of activated CD25-CD4 lymphocytes and release of cytokines in the bronchoalveolar space following segmental allergen challenge].

The aim of this study was to investigate the fundamental processes underlying the inflammatory response to allergen in mild non-symptomatic asthmatics, using a new model entailing endobronchial segmental provocation. Ten asymptomatic asthmatic volunteers (8 male, 2 female; mean age 28.2 [24-41] years) were challenged employing the segmental allergen provocation technique. 250 PNU in 5 ml 0.9% NaCl solution of either birch (n = 8) or grass (n = 2) pollen were instilled into one segment. As control, only the solvent was instilled into a segment of the contralateral lung. Bronchoalveolar lavage (BAL) with 100 ml prewarmed saline was performed 10 min and 18 h after allergen provocation. The cellular distribution and activation state in BAL fluid and peripheral blood was analysed by immunofluorescence and flow cytometry. The concentration of various cytokines was determined in the BAL fluid using ELISA and bioassays. In blood, segmental allergen provocation led to an increase both in numbers of neutrophils (3833 cells/microliters vs 6830 cells/microliters; P < 0.005) and activated IL-2R expressing (CD25+) CD4+ T cells (3.6% vs 4.8% of all CD4+ lymphocytes; P < 0.05). No change was observed in eosinophils and other leukocytes and lymphocyte subsets. In contrast, a significant 30-fold increase in eosinophils (0.39 x 10(6) vs 11.5 x 10(6) cells/100 ml; P < 0.01) and a twofold increase in CD25+ CD4+ T cells (P < 0.05) were found in BAL samples 18 h after segmental allergen challenge, when compared to the control segment. Analysis of the cytokine profile revealed significantly increased levels of several cytokines. Allergen challenge of extrinsic asthmatic subjects causes differentiation of activated CD25+ CD4+ lymphocytes which may contribute to the pathogenesis of the asthmatic inflammation through the release of various cytokines.

Adult↗
PubMed1995

Regulation of U-937 monocyte adhesion to cultured human mesangial cells by cytokines and vasoactive agents.

Leukocyte adhesion to kidney cells is an early event in renal inflammation, such as glomerulonephritis. We developed an experimental model of monocyte adhesion to cultured human mesangial cells. U-937 myelomonocytic leukaemia cells, similar to peripheral blood human monocytes, irreversibly bound to mesangial cell monolayers upon 30-180 min coincubations (to a max. of 13,600 +/- 1100/cm2 monolayer), as assessed by cell counting, U-937 labelling with 3H-thymidine, and colorimetry of nuclear staining with crystal violet. Adhesion was enhanced in mesangial cells proliferating in response to 17% fetal bovine serum, indicating expression of a proinflammatory phenotype. E. coli lipopolysaccharide (LPS), tumour necrosis factor-alpha (TNF-alpha) and protein kinase C activation with phorbol myristate acetate (PMA) potentiated monocyte binding during either coincubation or 24-h pretreatment (0.1 microM PMA, +200 +/- 21%). Binding was also promoted by pretreatment with vasoconstrictors, such as the thromboxane A2 mimetic, U-46619 (10 nM-1 microM, max. +35 +/- 3%), or 1 microM angiotensin II (+64 +/- 4%). To elucidate the mechanisms of monocyte adhesion, we analysed the adhesion molecules expressed by human mesangial cells, employing reverse transcription/polymerase chain reaction to detect ICAM-1, VCAM-1 and E-selectin gene expression. Proliferating cells express VCAM-1 and ICAM-1, confirmed by immunocytochemical staining and 79 +/- 3% inhibition of stimulated adhesion by pretreatment of mesangial cells with an anti-ICAM-1 monoclonal Ab. E-selectin transcription was not detectable.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗