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C Kroegel

Publications and source records attributed to C Kroegel.

At least 19 recordsLinked to original sources
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↗
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

Immunocytochemical characterization of malignant mesothelioma and carcinoma metastatic to the pleura: IOB3--a new tumor marker.

We have tried to find a reliable panel of markers that would allow distinction between mesotheliomas and carcinomas metastatic to the pleura. In a prospective study, we evaluated 54 pleural effusions: In 27 of the patients, a diagnosis of histologically proven metastatic carcinoma was subsequently established, 7 patients had biopsy-proven malignant mesotheliomas and 20 had benign, reactive effusions whose benign etiologies were established by more than 2 years clinical follow-up. The MAb (monoclonal antibody) IOB3 proved to be diagnostic for carcinomas in all 27 cases (100%), whereas CEA (carcinoembryonic antigen) expression was found in only 22 out of 27 (81%). None of the malignant mesotheliomas, nor benign reactive mesothelial cells reacted with these two markers. All carcinomas, as well as one malignant mesothelioma, reacted with the MAb HEA125. Antibodies against 12 single cytokeratins, vimentin, and EMA (epithelial membrane antigen) were not helpful in the differentiation between malignant mesotheliomas and malignant carcinomatous pleural effusions. We conclude that adding the antibody IOB3 to the CEA assay should allow a reliable differentiation between these two entities.

Adult↗
PubMed1995

Mechanisms of human eosinophil activation by complement protein C5a and platelet-activating factor: similar functional responses are accompanied by different morphologic alterations.

The complement system is an important amplification system for the propagation of allergic as well as pseudoallergic inflammatory reactions. In the present study, the effect of the major anaphylatoxin C5a was compared with that of platelet-activating factor (PAF) on highly purified eosinophils (> or = 95%) by functional as well as morphologic criteria. Upon stimulation with C5a, eosinophils maintained their spheric structure, developing short, pseudopodia-like protrusions, whereas PAF induced the generation of a number of digitating protrusions. As shown by functional and ultrastructural assay systems, both stimuli provoked significant extracellular and intracellular H2O2 production in eosinophils, which was inhibited by cytochalasin B. With C5a, a pronounced H2O2 production was detected within the small cytoplasmic vesicles, whereas PAF-induced H2O2 production was observed on the outer surface of the plasma membrane in the contact zones between adjacent cells. Morphologic signs of degranulation induced by C5a and PAF were accompanied by the significantly increased release of eosinophil cationic protein and eosinophil peroxidase in the presence of cytochalasin B. Like PAF, C5a induced a significant production of reactive oxygen species in eosinophils, as measured by lucigenin-dependent chemiluminescence (CL) responses in eosinophils. Maximal responses, comparable with those of interleukin-5 (100 U/ml), were observed at concentrations of 10(-5)-10(-6) and 10(-7)-10(-8) M for PAF and C5a, respectively. Separation of eosinophils by discontinuous density gradients revealed the existence of two hypodense eosinophil populations, one of them showing significantly reduced CL responses upon stimulation with C5a and PAF. In addition, CL responses upon stimulation with C5a and PAF were abrogated by cytochalasin B, staurosporine, and wortmannin, and were almost completely blocked by pertussis toxin. In conclusion, these data indicate that C5a induces events in human eosinophils comparable to those induced by PAF in the assay systems tested. Thus, C5a, generated after activation of the complement system, may be of major importance for the eosinophil activation observed in eosinophil-related disease.

Blood Proteins↗
PubMed1995

T cells and cytokines in bronchoalveolar lavage fluid after segmental allergen provocation in atopic asthma.

Increasing evidence suggests a role for activated T cells and cytokines in the regulation of eosinophilic inflammation in asthma. In this study, we investigated the distribution of leukocytes, lymphocytes, their activation state, and the cytokine profile in BAL from 10 atopic asthmatics with positive skin prick tests and elevated specific IgE levels to birch or grass pollen. Using segmental allergen challenge, 250 PNU of the appropriate allergen or saline were instilled into different segments, which were lavaged 10 min (10 min) and 18 h (18 h) after allergen challenge or 18 h after saline challenge (C). In peripheral blood the number of neutrophils and activated IL-2R+/CD4+ T cells increased significantly 18 h after allergen provocation; there was no change in eosinophils, other leukocytes, or lymphocyte subsets. In contrast, numbers of eosinophils, neutrophils, and IL-2R+/CD4+ T cells increased significantly in BAL samples at 18 h. The numbers of neutrophils and eosinophils were not significantly different in the lavage performed at 10 min and at C. Analysis of cytokines in concentrated BAL fluid revealed significantly increased levels of IL-5, IL-2, IL-1, TNF-alpha, IL-6, IL-8, and GM-CSF, but not of IL-4 and IFN-gamma at 18 h compared with those at C and at 10 min. The correlation between IL-5 levels, eosinophil numbers, and activated T cells supports a role for T-cell-derived IL-5 in causing tissue eosinophilia in allergic asthma.

Adult↗