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C Kroegel

Publications and source records attributed to C Kroegel.

At least 19 recordsLinked to original sources
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

Evidence for eosinophil activation in bronchiectasis unrelated to cystic fibrosis and bronchopulmonary aspergillosis: discrepancy between blood eosinophil counts and serum eosinophil cationic protein levels.

BACKGROUND: Increased serum levels of eosinophil cationic protein (ECP) have been detected in adolescent patients with cystic fibrosis. However, ECP concentrations in adult patients with bronchiectasis unrelated to cystic fibrosis have not been studied. METHODS: Eosinophil numbers and serum concentrations of ECP were determined in 14 patients with known or newly diagnosed bronchiectasis and compared with age and sex matched patients with allergic bronchial asthma, chronic obstructive pulmonary disease (COPD), and controls in whom bronchiectasis or obstructive pulmonary disease could be excluded. RESULTS: Serum ECP levels were significantly raised both in patients with bronchiectasis (median (range) 22.5 micrograms/l (7-85)) and allergic asthma (35.0 micrograms/l (7-128)) compared with the sex and age matched subjects suffering from COPD (6.7 micrograms/l (1.5-28); p < 0.006) and non-obstructive normal controls (7.5 micrograms/l (3.5-19); p < 0.003). In contrast, significantly increased peripheral eosinophil numbers were observed in patients with bronchial asthma (305 x 10(6)/l; p < 0.01) but not in those with bronchiectasis (10(2) x 10(6)/l), COPD (117 x 10(6)/l), and healthy controls (101 x 10(6)/l). CONCLUSIONS: The discrepancy between eosinophil counts and eosinophil numbers in patients with bronchiectasis suggests that serum ECP levels may be more relevant in assessing local eosinophil involvement than blood eosinophil numbers.

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↗
PubMed1998

[Leukotriene receptor antagonists and bronchial asthma].

Leukotrienes play an important role in the pathogenesis of the allergic bronchial asthma. The cysteinyl-leukotrienes C4, D4 and E4 (formerly known as slow reacting substance of anaphylaxis, SRS-A) are able to induce all components of the asthmatic reaction. The synthesis of adequate receptor antagonists stimulated expectations to develop on this way new and especially effective antiasthmatic drugs. The results of the first generation was disappointing. Newer compounds are able to protect from bronchoconstriction-inducing noxes (especially in analgesic intolerance), to improve chronic asthma (symptoms scores, long-time resp. rescue medication). Especially remarkable are recent data which prove antiinflammatory activities. Studies are underway to define the position of these drugs in generally accepted recommendations on asthma therapy. This group of drugs is the first one with a defined action.

Animals↗
PubMed1997

[Recommendations for systematization of national guidelines for treatment of bronchial asthma in adulthood in Germany].

BACKGROUND: Medical guidelines provide boundaries that are established for the medical community, within which clinical practice is considered to be acceptable. The main purpose for such guidelines is to improve the quality of care for patients. This can only be accomplished, however, if these documents are accepted and used effectively. In turn, acceptance of therapy guidelines essentially depends on both the structure and the presentation of the contents. GUIDELINES FOR THE TREATMENT OF ASTHMA were first issued in 1994 by the Deutsche Atemwegsliga. Since then, almost 4 years have passed, and our knowledge of the pathogenesis of asthma and drug efficacy has improved significantly. In addition, new classes of antiasthmatic drugs will be soon available. These developments make it necessary to adapt the guidelines to current knowledge. PROPOSALS FOR IMPROVEMENT: The paper proposes several aspects on improving the present guidelines and aims at fueling future discussions.

Adult↗
PubMed1997

Immunobiology of pleural inflammation: potential implications for pathogenesis, diagnosis and therapy.

Although infectious, inflammatory and neoplastic diseases frequently involve the pleural space and walls, little is known about the immunological and molecular mechanisms underlying pleural disorders. This article provides an overview of recent insights into immunobiological processes likely to play a role in the pathogenesis of pleural disorders. Pleural involvement in certain diseases is associated with the infiltration of a number of different types of immune cells, such as neutrophils, eosinophils or lymphocytes, in various proportions depending on both the course and the aetiology of the underlying disease. In addition to infiltrating cells, mesothelial cells have been demonstrated to actively participate in pleural inflammation via release of various mediators and proteins, including platelet-derived growth factor (PDGF), interleukin-8, monocyte chemotactic peptide (MCP-1), nitric oxide (NO), collagen, antioxidant enzymes and the plasminogen activation inhibitor (PAI). Furthermore, several inflammatory mediators have been detected at increased concentrations within pleural effusions, including lipid mediators, cytokines and proteins (adenosine deaminase, lysosyme, eosinophil-derived cationic proteins, and products of the coagulation cascade). The presence of these mediators underline the concept of pleural inflammation, and certain cytokines seem to characterize a specific aetiology of pleurisy. The understanding of these processes and the sequence of events leading to pleural loculation, pleural adhesion or repair are likely to provide the basis for early therapeutic intervention and reduce pleural-associated morbidity.

Cells, Cultured↗
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

Differential expression of alpha E beta 7 integrins on bronchoalveolar lavage T lymphocyte subsets: regulation by alpha 4 beta 1-integrin crosslinking and TGF-beta.

T lymphocytes expressing the alpha E beta 7 integrin are localized and selectively retained in mucosal tissues. To investigate a potential relationship between alpha E beta 7 expression and pulmonary inflammation, the distribution of alpha E beta 7-bearing CD4+ and CD8+ T cells in peripheral blood and bronchoalveolar lavage (BAL) fluids obtained from patients with allergic asthma, sarcoidosis, hypersensitivity pneumonitis, and idiopathic pulmonary fibrosis (IPF) was determined. In contrast to the distribution in peripheral blood, BAL fluid from these patients contained high number of cells expressing alpha E beta 7 with markedly different expression patterns on CD4 or CD8 cells as well as among the various diseases. Despite similar numbers of activated CD4 cells, alpha E beta 7+CD4+ T cells ranged from 15% in asthmatics to 70% in IPF. In contrast, even in normal individuals, 60% to 90% of BAL fluid CD8+ T cells express alpha E beta 7, suggesting differential induction mechanisms on CD4 and CD8 cells. In vitro experiments revealed that a substantial proportion of peripheral blood CD+ T cells express alpha E beta 7 after stimulation with anti-CD3 antibodies, and up to 80% positive cells were found after the addition of TGF-beta. In contrast, less than 10% of CD4 cells express this particular integrin after in vitro stimulation, and the presence of TGF-beta only increased the number to 30%. Supernatants from in vitro-activated BAL cells as well as concentrated BAL fluid from patients with high alpha E beta 7 expression had no further enhancing effect. However, crosslinking of alpha 4 beta 1-, but not beta 2-integrins, significantly increased the number of alpha E beta 7 expressing CD4+ and CD8+ T cells, even in the absence of TGF-beta. These data indicate that in addition to TGF-beta, the interaction of particular T-cell subsets with specific endothelial cell and extracellular matrix proteins may upregulate alpha E beta 7 integrin expression and thereby contribute to the selective accumulation of these cells in inflammatory lung diseases.

Adult↗
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

Inflammatory determinants of asthma severity: mediator and cellular changes in bronchoalveolar lavage fluid of patients with severe asthma.

Cellular and mediator profiles in bronchoalveolar lavage have not been compared systematically between patients with asthma of different severities, mainly because the patients with more severe asthma have an increased need for antiinflammatory medication. Information is limited to comparisons of allergic and intrinsic asthma, which can be distinguished clinically. When patients from these two groups with similar degrees of bronchial hyperresponsiveness were compared, both groups showed increased numbers of activated T-helper lymphocytes; those in the allergic group expressed the IL-2 receptor (CD25+), whereas in patients with intrinsic asthma there was also an increased number of T-suppressor cells with the activation markers CD25, class II histocompatibility antigen, and very late activation antigen-I, as well as T-helper cells class II histocompatibility antigen and very late activation antigen-I. This pattern is compatible with a more chronic T-cell activation in patients with intrinsic asthma. In patients with allergic asthma the cytokine pattern is compatible with a pure TH2 response (elevated IL-4 and IL-5); however, intrinsic asthma is characterized by elevated IL-5 and IL-2 but not IL-4. Our own findings show similar concentrations of IL-1, IL-8, and granulocyte-macrophage colony-stimulating factor in bronchoalveolar lavage fluid of patients with allergic and intrinsic asthma, whereas IL-6 and interferon-gamma tended to be higher in patients with intrinsic asthma. There are probably fundamental differences in the pathogenesis of allergic and intrinsic asthma. These findings suggest that asthma does not depend on the presence of IgE or IL-4, although both may contribute to the pathogenesis of atopic asthma. The only common pathway in the different presentations of asthma that has been related to clinical symptoms appears to be IL-5-mediated activation of eosinophils; therapies aimed at this mechanism may be promising.

Asthma↗