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PubMed1977

Chronic eosinophilic pneumonia. Ultrastructural evidence of marked immunoglobulin production plus macrophagic ingestion of eosinophils and eosinophilic lysosomes leading to intracytoplasmic Charcot-Leyden crystals.

A 60-year-old man was diagnosed as having chronic eosinophilic pneumonia by clinical presentation and open lung biopsy. Electron microscopic study of the tissue from biopsy revealed evidence of marked production of immunoglobulin, which may be part of the chemotactic process which attracted large numbers of eosinophils into the area. Also, there were macrophages which were phagocytosing degenerating eosinophils and eosinophilic lysosomes. Charcot-Leyden crystals were noted in the cytoplasm of many macrophages. The relationship of the production of immunoglobulin to the eosinophilia and the mechanism of intramacrophagic formation of Charcot-Leyden crystals is discussed.

Humans↗
PubMed1999

Wells' syndrome (eosinophilic cellulitis): correlation between clinical activity, eosinophil levels, eosinophil cation protein and interleukin-5.

Wells' syndrome (WS) (eosinophilic cellulitis) is characterized by the presence of oedematous skin lesions associated with eosinophilia of the tissues. It has recently been observed that in patients with this disease, increased eosinophil cation protein (ECP) and interleukin (IL) -5 can be detected in peripheral blood, with T lymphocytes that have mRNA for this lymphokine. We present a patient with WS in whom we found a close correlation between clinical activity, eosinophils in blood and bone marrow, and ECP and IL-5 levels in peripheral blood and tissues. We underline the major part played by IL-5 in this disease.

Adult↗
PubMed1987

Eosinophil chemotactic lymphokine produced by spleen cells of Schistosoma japonicum-infected mice. III. Isolation and characterization of two distinctive eosinophil chemotactic lymphokines directed against different maturation stages of eosinophils.

Two distinctive types of eosinophil chemotactic lymphokines (ECF-L) directed against eosinophils obtained from bone marrow (BM-Eo) or from peritoneal cavity (PEC-Eo) were isolated from the media conditioned by spleen cells from mice infected with Schistosoma japonicum by a combination of anion-exchange chromatography on DE52, affinity chromatography on Procion Red agarose, and high-performance liquid chromatography. The molecular weight of ECF-L directed against BM-Eo was 10,000 and that against PEC-Eo was 46,000 by SDS-PAGE analysis. After isolation, selectivity of the two distinct ECF-L was examined using BM-Eo, PEC-Eo and circulating Eo. ECF-L directed against BM-Eo could attract only BM-Eo, whereas that directed against PEC-Eo could attract not only PEC-Eo but also circulating Eo. Synthetic ECF-A was chemotactic against both BM- and circulating-Eo but not against PEC-Eo. When BM-Eo were cultured with ECF-L selective to PEC-Eo, they became reactive to ECF-L selective to PEC-Eo, whereas ECF-L selective to BM-Eo did not have such effect. These results suggest that ECF-L selective to PEC-Eo is not simply a chemoattractant but also is important in eosinophil differentiation.

Animals↗
PubMed1985

Detection of eosinophils using an eosinophil peroxidase assay. Its use as an assay for eosinophil differentiation factors.

A colorimetric assay for peroxidase has been applied to the detection of eosinophils in bone marrow cultures and tissue cell suspensions. The substrate solution consists of 0.1 mM o-phenylenediamine in 0.05 M Tris-HCl buffer pH 8.0 containing 0.1% Triton and 1 mM hydrogen peroxide. The method is shown to be an easy and reproducible method of detecting eosinophils, with insignificant interference from neutrophils.

Amitrole↗
PubMedDate not supplied

[Vasomotor skin tests in non-eosinophilic and eosinophilic long-term (perennial) nonallergic rhinitis].

INTRODUCTION: It has generally been assumed that "perennial" non-allergic rhinitis is a heterogeneous syndrome consisting of at least two groups: non-eosinopilic and eosinophilic. Opposite to non-eosinophilic group, eosinophilic group is characterized by nasal secretion eosinophilia, frequent evolution to nasal polyposis or complete ASA triad (nasal polyposis, intrinsic asthma and intolerance of non-steroidal anti-inflammatory drugs) and by a good response to treatment with anti-histamines and corticosteroids. These characteristics obviously separate eosinophilic from non-eosinophilic rhinitis and point out the importance of nasal secretion eosinophilia for the evolution and therapy of rhinitis. However, the distinction between eosinophilic and non-eosinophilic rhinitis can only be made by nasal cytology. Skin tests with vasomotor agents were carried out to characterize vasomotor skin reactivity in "perennial" non-allergic rhinitis and determine whether the patients with non-eosinophilic rhinitis differ from patients with eosinophilic rhinitis. METHODS: On the basis of the examination of nasal smears of eosinophils, 74 patients with "perennial" non-allergic rhinitis were divided into non-eosinophilic (n = 63) and eosinophilic group (n = 11). Nasal eosinophilic was considered significant when 20% and more of the cells in nasal smear were eosinophils. Skin reactivity to intracutaneous test with different concentrations of papaverine, metacholine, histamine and compound 48/48 was measured, as well as specific skin reactivity to control saline solution. Pathological skin reactivity to vasomotor agents was defined as hyporeactivity to papaverine (5 mg/mL), when wheal-and-flare skin reaction diameter was less than 15 mm; hyper-reactivity to metacholine (0.02, 0.2 and 2.0 mg/mL), when two of three wheal-and-flare skin reaction diameters were greater than 15, 25 and 31 mm, respectively; hyper-reactivity to histamine (0.01, 0.1, 1.0 and 10.0 micrograms/mL), when three of four wheal-and-flare skin reaction diameters were greater than 7, 13, 25 and 40 mm, respectively; and hyper-reactivity to compound 48/80 (0.01, 0.1, 1.0 and 10.0 micrograms/mL, when three of four wheal-and-flare skin reaction diameters were greater than 9, 16, 26 and 38 mm, respectively. RESULTS: Seventy four patients with "perennial" non-allergic rhinitis were included in the study. There were 51 females, age range from 18 to 57 yrs. (mean 37 yrs.) and 23 males, age range from 18 to 73 yrs. (mean 44 yrs.). The difference between the number of females and males was significant (p = 1.1 x 10(-3)), while no significant difference regarding the age between females and males was found (p = 0.122). Significant percentage of eosinophils was found in 15% of "perennial" non-allergic rhinitis patients, and they were classified into eosinophilic group (n = 11). In this group, the percentage of eosinophils varied from 20% to 80%, mean 35%. In non-eosinophilic group (n = 63), it ranged from 0% to 10%, mean 1%. No significant difference concerning sex and age between the two groups of the rhinitis patients was observed (Table 1). There was no significant intergroup difference for pathological skin reactivity to papaverine, metacholine, histamine, compound 48/80 and saline (Table 2). Total pathological skin reactivity to vasomotor agents, single and in combination, was found in 78% of non-eosinophilic and in 91% of eosiniophilic rhinitis patients (Table 3). In both, non-eosinophilic and eosinophilic groups, frequencies of total pathological skin reactivity to vasomotor agents was significantly greater than frequencies of total normal skin reactivity (p = 1.1 x 10(-5) and p = 0.007 respectively). However, the difference of total pathological skin reactivity to vasomotor agents between the two groups was not significant (p = 0.552). (ABSTRACT TRUNCATED)

Adolescent↗
PubMed1985

Eosinophil- and eosinophil granule-mediated pneumocyte injury.

The function of the eosinophil in eosinophilic pulmonary syndromes and asthma is uncertain. To determine if eosinophils might play a harmful role in these conditions, we cocultured purified human eosinophils, eosinophil major basic protein (MBP), and chromatographically eluted eosinophil granule fractions with human A549 and rat type II pneumocytes. Damage to these target cells was measured as cell lysis and nonlethal cell detachment. We found that unstimulated intact eosinophils affected minimal lysis or detachment of either pneumocyte target, but eosinophils stimulated with phorbol myristate acetate and other activators produced time- and dose-dependent nonlytic detachment of both targets. In contrast, supernatants from activated eosinophils did not produce significant injury, suggesting that close apposition of the effector and target cells was required. Catalase and superoxide dismutase did not inhibit the detaching activity of eosinophils, suggesting that hydrogen peroxide and superoxide anion were not activity of eosinophils, suggesting that hydrogen peroxide and superoxide anion were not responsible for mediating this form of injury. In contrast to our findings with intact eosinophils, we observed that the addition of purified eosinophil MBP to pneumocytes caused marked cytolysis with little detachment. When sequential fractions of eosinophil granules separated by Sephadex G-50 chromatography were added to A549 and rat type II pneumocyte targets, it was found that different fractions produced distinct forms of injury. Higher molecular weight fractions containing lysosomal enzymes and eosinophil peroxidase produced predominantly detachment, whereas fractions enriched in MBP produced lysis. These results indicate that intact eosinophils can produce nonlytic detachment of alveolar pneumocytes that is probably not dependent on the generation of toxic oxygen radicals but rather appears to be mediated by granule-associated products, possibly lysosomal enzymes. Furthermore, although intact eosinophils are not capable of lysing alveolar epithelial cells under the conditions of our assay, MBP has the potential to do so when the protein is released in high enough concentrations. The in vivo relevance of these findings in eosinophilic lung diseases may be that eosinophils, by producing both desquamation and death of alveolar epithelium cells, may increase the permeability of the alveolus to fluid and cells. Moreover, these forms of damage might also enhance the ingress of inhaled antigens across the pulmonary epithelial barrier, thus increasing immunologic sensitization.

Animals↗
PubMed1993

Segregation of eosinophil proteins in alveolar macrophage compartments in chronic eosinophilic pneumonia.

BACKGROUND: The objective was to characterise the process and consequences of eosinophil activation and lysis in patients with chronic eosinophilic pneumonia and to compare them with those in patients with eosinophil pulmonary infiltrates from other causes. METHODS: Cells from bronchoalveolar lavage fluid of four patients with chronic eosinophilic pneumonia and four patients with eosinophilic infiltrates associated with Sjögren's syndrome, drug hypersensitivity pneumonia, postradiotherapy fibrosis, and pulmonary disease associated with graft versus host disease were studied ultrastructurally and with immunogold labelled antibodies directed against eosinophil proteins: major basic protein, eosinophil cationic protein, and Charcot-Leyden crystal protein. The concentration of eosinophil cationic protein was also measured in bronchoalveolar fluid. RESULTS: In the four patients with chronic eosinophilic pneumonia, ultrastructural studies demonstrated numerous lysed eosinophils. Further, three released eosinophil proteins were detected in distinct cytoplasmic structures in alveolar macrophages. These features were not found in the four patients with eosinophilic pulmonary infiltrates from other causes. CONCLUSION: Eosinophils in chronic eosinophilic pneumonia show signs of activation with release of eosinophil proteins. The appearance of three of these eosinophil proteins in different macrophage compartments suggests that macrophage uptake, with or without intracellular transport of released eosinophil proteins, involves separate mechanisms. This interaction does not lead to macrophage lysis, however, and one or more of these eosinophil proteins might directly affect macrophage function.

Adult↗
PubMed2006

Eosinophil infiltration and degranulation in oesophageal mucosa from adult patients with eosinophilic oesophagitis: a retrospective and comparative study on pathological biopsy.

AIM: To examine eosinophil infiltration and degranulation in 50 oesophageal biopsy specimens from 30 patients (21 men, 9 women; mean 39 years) with eosinophilic oesophagitis, by haematoxylin and eosin staining and immunohistochemistry. METHODS: Immunohistochemistry was carried out using a monoclonal antibody for human eosinophilic major basic protein (MBP). Eosinophils were counted in three high power fields (x40) and degranulation, as quantified by extracellular MBP immunostaining, was scored on a scale of 1-4. Morphological changes (basal cell hyperplasia, elongation of papillae and dilatation of intercellular spaces) were scored on a 1-4 scale on sections stained with haematoxylin and eosin. RESULTS: Numbers of intraepithelial eosinophils were significantly higher with MBP immunostaining than with haematoxylin and eosin staining (mean 109.6 v 80.6; p<0.001), whereas numbers of eosinophils were considerably correlated (r = 0.794). Eosinophil degranulation was higher in the distal oesophagus. Additionally, basic morphological changes were markedly associated with eosinophil infiltration. Extracellular deposition of eosinophil-MBP and eosinophil infiltration in subepithelial connective tissue, present in the biopsy specimens, were detected by immunohistochemistry. CONCLUSION: Numbers of eosinophils and degranulation are underestimated by haematoxylin and eosin staining. Immunohistochemistry detected up to two times more eosinophils than routine haematoxylin and eosin staining. Moreover, eosinophil-MBP immunoreactivity in extracellular regions indicates the release of toxic eosinophil granule proteins and gives further evidence for a causative role of eosinophils with regard to structural changes in eosinophilic oesophagitis. Immunohistochemistry may serve as a useful diagnostic tool to support the morphological differential diagnosis of eosinophilic oesophagitis and gastro-oesophageal reflux disease.

Adult↗
PubMed1991

Eosinophil differentiation of human umbilical cord mononuclear cells and prolonged survival of mature eosinophils by murine EL-4 thymoma cell conditioned medium.

Umbilical cord mononuclear cells, HL-60 cells, HL-60 clones selected for eosinophil differentiation, and the eosinophil leukemia cell line EoL were tested for their ability to produce eosinophil peroxidase. HL-60 clones selected for eosinophil differentiation produced eosinophil peroxidase, as judged by staining of cells for cyanide-resistant peroxidase activity; however, these cells lost their ability to produce eosinophil peroxidase in long-term culture. In contrast, eosinophil precursors from human umbilical cord blood mononuclear cells stimulated with murine EL-4 conditioned medium (EL-4 CM) were regularly induced to eosinophil protein synthesis, including eosinophil peroxidase, major basic protein, eosinophil cationic protein, and eosinophil-derived neurotoxin, as assessed by cyanide-resistant peroxidase and immunofluorescence staining. This induction by EL-4 CM is either at the level of gene transcription or mRNA stabilization, as shown by the increase of total mRNA for eosinophil peroxidase, major basic protein, and eosinophil-derived neurotoxin by Northern blot analyses. Purified peripheral blood eosinophils incubated for 4 days with EL-4 CM had increased survival over control eosinophils. Moreover, this enhanced survival was specifically blocked by antiserum to interleukin 5. Our results suggest that the effects of EL-4 CM on human umbilical cord mononuclear cells and mature eosinophils are due to the presence of interleukin 5.

Animals↗
PubMed1997

Intercellular adhesion molecule-1 on eosinophils is involved in eosinophil protein X release induced by cytokines.

Recent evidence suggests that adhesion molecules play important roles in eosinophil functions such as degranulation and superoxide anion production. CD11b/CD18 (Mac-1) and CD49d/CD29 (VLA-4) are involved in eosinophil-endothelial adhesion through their counterligands, intercellular adhesion molecule-1 (ICAM-1; CD54) and vascular cell adhesion molecule-1 (VCAM-1), respectively. CD54 is also induced on eosinophils by cytokine stimulation. We hypothesized that CD54 on human eosinophils may participate in eosinophil degranulation. CD54 was induced on eosinophils by a combination of human recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF) and human recombinant tumour necrosis factor-alpha (rTNF-alpha) within 2 hr of incubation, as determined by flow cytometric analysis. Recombinant GM-CSF alone induced a slight but significant CD54 expression on eosinophils. Release of eosinophil protein X, an indicator of eosinophil degranulation, was induced by rGM-CSF and this effect was synergistically enhanced by adding rTNF-alpha. To determine the role of newly expressed CD54 in eosinophil degranulation, a blocking assay was performed using monoclonal antibody (mAb) against CD54 and CD18. Anti-CD18 mAb and anti-CD54 mAb markedly inhibited eosinophil degranulation induced by rGM-CSF or a combination of rGM-CSF and rTNF-alpha. On the other hand, anti-CD54 mAb had little effect on rGM-CSF- or rGM-CSF/rTNF-alpha-induced adhesion of eosinophils, whereas anti-CD18 mAb significantly inhibited eosinophil adhesion. These results indicate that CD54 on eosinophils plays an important role in the eosinophil degranulation and that eosinophils are capable of interacting with other beta 2 integrin-positive cells.

Antibodies, Monoclonal↗
PubMed2003

Eosinophilic pancreatitis and increased eosinophils in the pancreas.

Prominent eosinophilic infiltrates are an unusual finding in the pancreas. Eosinophilic pancreatitis is one rare etiology of pancreatic eosinophilia, but other described causes of eosinophilic infiltrates have also included pancreatic allograft rejection, pancreatic pseudocyst, lymphoplasmacytic sclerosing pancreatitis (LPSP), inflammatory myofibroblastic tumor, and histiocytosis X. In this study we describe the clinicopathologic features of three new cases of eosinophilic pancreatitis and conduct a retrospective 18-year institutional review of the myriad disease processes associated with pancreatic eosinophilia. In the files of the Johns Hopkins Hospital, <1% of all pancreatic specimens had been noted to show increased numbers of eosinophils. Eosinophilic pancreatitis itself was a rare etiology for pancreatic eosinophilia, with only one in-house case over the 18-year study period and two additional referral cases. Other disease processes associated with prominent eosinophilic infiltrates were more common and included pancreatic allograft rejection (14 cases), LPSP (5 of 24 total LPSP cases evaluated), inflammatory myofibroblastic tumor (4 cases), and systemic mastocytosis (1 case). Patients with eosinophilic pancreatitis showed two distinct histologic patterns: 1) a diffuse periductal, acinar, and septal eosinophilic infiltrate with eosinophilic phlebitis and arteritis; and 2) localized intense eosinophilic infiltrates associated with pseudocyst formation. All three patients with eosinophilic pancreatitis had peripheral eosinophilia, and all had multiorgan involvement. One patient with LPSP also had marked peripheral eosinophilia, and 5 of 24 LPSP cases demonstrated prominent eosinophilic infiltrates in the gallbladder, biliary tree, and/or duodenum. Notably, not all of these patients with LPSP with prominent eosinophils in other organs had increased eosinophils in the pancreas itself. These results emphasize the infrequent nature of pancreatic eosinophilia and its multiple potential disease associations. True eosinophilic pancreatitis, although a fascinating clinicopathologic entity, is one of the rarest causes of pancreatic eosinophilia.

Adult↗
PubMed1997

Eosinophil protein X concentration is dependent on eosinophil concentration.

The relationship between the eosinophil concentration and the serum eosinophil protein X concentration was investigated in 80 subjects. Higher eosinophil counts resulted in obviously increased serum eosinophil protein X concentrations. However, the amount of eosinophil protein X released per eosinophil granulocyte is significantly higher in subjects with lower eosinophil counts. Atopic subjects (N = 19) show a significantly higher eosinophil concentration (p = 0.002) and eosinophil protein X concentration (p = 0.004) and a significantly lower eosinophil protein X/eosinophil ratio (p = 0.02), compared with non-atopic subjects (N = 61). However, there appears to be no difference between the concentration of eosinophil protein X in atopic and non-atopic subjects if the eosinophil concentration is taken into account. When using eosinophil protein X as an indicator of eosinophil activation, for instance in asthmatic subjects, the eosinophil count should also be considered for correct clinical interpretation of results.

Adolescent↗
PubMed1993

Synthesis of interleukin-5 by activated eosinophils in patients with eosinophilic heart diseases.

Eosinophilic endomyocardial disease represents a major evolutive risk in chronic eosinophilia-associated disorders. Eosinophil granule proteins appear to be involved in cardiac injury, but the mechanisms leading to eosinophil infiltration and degranulation are not clear. Interleukin-5 (IL-5) has been recently shown to be produced by eosinophils and might play a role in both chemoattraction and degranulation of eosinophils. In four cases of eosinophilic diseases with severe cardiac failure, we evaluated the proportion of eosinophil phenotypes and the serum levels of eosinophil cationic protein (ECP) and soluble IL-2 receptor (sIL-2R), markers of disease activity in the hypereosinophilic syndromes. All four patients showed a markedly increased proportion of hypodense eosinophils with elevated serum ECP and sIL-2R levels. In all four patients, extracellular deposition of eosinophil granule proteins and features of eosinophil activation were observed in cardiac tissues. The synthesis of IL-5 by eosinophils was detected in myocardial sections and blood cells by in situ hybridization and by immunostaining with a monoclonal antibody against human IL-5. Sixty percent to 90% of tissue eosinophils expressed IL-5 mRNA and IL-5 protein. These data suggest that IL-5 can be produced by eosinophils at the sites of myocardial tissue damage and might participate in local eosinophil activation.

Biopsy↗
PubMed1997

Lack of Fc-epsilon receptors on murine eosinophils: implications for the functional significance of elevated IgE and eosinophils in parasitic infections.

Chronic infection with Schistosoma mansoni induces in humans and mice a Th2-dominant immune response in which eosinophils and IgE are conspicuously elevated. Human eosinophils express IgE receptors that participate in an IgE-dependent eosinophil-mediated ADCC reaction against Schistosomula larvae in vitro. To investigate the expression of IgE receptors on murine eosinophils, they were purified (>95% pure by Giemsa-stained cytospin preparations) from liver granulomas of Schistosoma-infected mice. Flow cytometric analysis showed the absence of the low-affinity IgE receptor Fc-epsilon RII (CD23) and Mac-2 and the absence of binding of murine IgE. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of granuloma eosinophil mRNA did not detect transcripts for Fc-epsilon RII or the alpha-chain of the high-affinity IgE receptor Fc-epsilon RI, but did detect transcripts that encode Mac-2 and the low-affinity IgG receptors Fc-gamma RIIb2, Fc-gamma RIII, and the FcR-associated gamma-chain. In vitro stimulation of granuloma eosinophils with interleukin-4 (IL-4) did not induce IgE binding, surface expression of Mac-2, or the transcription of Fc-epsilon receptors (Fc-epsilon RI, Fc-epsilon RII/CD23). To investigate normal murine eosinophils, we cultured normal mouse bone marrow cells with recombinant IL-3, recombinant IL-5, and recombinant granulocyte-macrophage colony-stimulating factor, conditions that promote eosinophil differentiation. Flow cytometric analysis of bone marrow-derived eosinophils failed to detect IgE binding or cell surface expression of Fc-epsilon RII and Mac-2, and RT-PCR analysis of fluorescence-activated cell sorted bone marrow-derived eosinophils failed to detect transcripts that encode Fc-epsilon RI or Fc-epsilon RII. These findings show that, in contrast to human eosinophils, murine eosinophils do not express cell surface receptors that bind IgE. However, because IgG receptors (Fc-gamma RIIb2, Fc-gamma RII) were present on eosinophils purified from granulomas, we investigated whether they might be involved in eosinophil activation. We found that an oxidative burst in eosinophils could be triggered through their IgG receptors.

Animals↗
PubMed1984

Eosinophil-mediated injury to lung parenchymal cells and interstitial matrix. A possible role for eosinophils in chronic inflammatory disorders of the lower respiratory tract.

Eosinophils are a common component of the inflammation of the lower respiratory tract that characterizes the interstitial lung disorders. Bronchoalveolar lavage analyses (n = 680) of 251 patients with interstitial lung disease demonstrated that eosinophils represented greater than 5% of the effector cells comprising the alveolitis in 20% of all lavages. In contrast, lavage of normal individuals (n = 117) showed that eosinophils were never greater than 5% of the total effector cells recovered. To evaluate a possible role for eosinophils in mediating some of the cellular and connective tissue matrix derangements of the lung parenchyma found in interstitial disease, eosinophils were evaluated for the presence of proteases capable of cleaving connective tissue proteins found in the lung and for the ability to mediate cytotoxicity to lung parenchymal cells. Evaluation of guinea pig and human eosinophils demonstrated that eosinophil granules contained a collagenase that specifically cleaved human collagen types I and III, the two major connective tissue components of the human lung parenchyma. In contrast, the eosinophil did not contain an elastase or a nonspecific neutral protease. The eosinophil collagenase appeared to be a metalloprotease, as it was inhibited by ethylenediaminetetraacetate but not by phenylmethanesulfonyl-fluoride or alpha 1-antitrypsin. The eosinophil also has the capacity to injure lung parenchymal cells. Without further stimulation, eosinophils purified from peritoneal exudates of guinea pigs demonstrated spontaneous cytotoxicity for human lung fibroblasts (HFL-1), cat lung epithelial cells (AK-D) and rat lung mesothelial cells (I6B). Under identical conditions, the epithelial cells were more sensitive to eosinophil-mediated cytotoxicity than the fibroblasts or mesothelial cells (P less than 0.01), consistent with the clinical observation that in the interstitial disorders, the alveolar epithelial cells are damaged more commonly than fibroblasts or pleural cells. The eosinophil-mediated cytotoxicity could be partially inhibited by the antioxidants catalase and dimethylsulfoxide suggesting that toxic oxygen radicals play a role in mediating the cellular damage. Importantly, eosinophils purified from bronchoalveolar lavage of human interstitial lung disease also demonstrated spontaneous cytotoxicity for lung epithelial cells. These observations demonstrate that eosinophils are frequent participants of the alveolitis of the interstitial lung disorders and suggest that these cells have the potential to damage the parenchymal cells and collagen matrix of the lower respiratory tract.

Animals↗
PubMed1999

Eosinophil activation by eotaxin--eotaxin primes the production of reactive oxygen species from eosinophils.

BACKGROUND: The CC chemokine eotaxin has been shown to possess selective chemotactic activity for eosinophils, the major effector cells in allergic inflammation. Reactive oxygen species (ROS) from eosinophils may damage cells or tissue, such as the mucosal epithelium. In this study, we examined the effect of eotaxin on ROS from eosinophils and compared its activity with RANTES and interleukin (IL)-5. Moreover, we examined the signal transduction of eotaxin and the effect of dexamethasone on ROS from eosinophils. METHODS: Eosinophils were isolated by modified CD16-negative selection. ROS in luminol-dependent or lucigenin-dependent chemiluminescence reaction were examined. Calcium ionophore A23187 was added to the mixture of eosinophils with luminol or lucigenin, and then ROS were determined. RESULTS: Eotaxin primed the production of ROS in a dose-dependent manner. ROS from untreated eosinophils evoked with calcium ionophore A23187 in luminol-dependent chemiluminescence gave a maximal value of 4957+/-1035 intensity counts (IC) (mean+/-SE, n=7) and an integral value of 15.75+/-3.14 IC (x10(-4)), while eosinophils that were treated with eotaxin gave maximal values of 11 142+/-2300 IC (10 nM) and 29165+/-3718 IC (100 nM) and integral values of 41.07+5.44 IC (x10(-4)) (10 nM) and 152.90+/-22.38 IC (x10(-4))(100 nM). Moreover, eotaxin was less effective as a priming agent with lucigenin-sensitive pathways than luminol-sensitive pathways. Among several kinds of eosinophils activating cytokines and chemokines, the priming effect of eotaxin on RO5 was the most potent. Eotaxin-primed ROS were inhibited by pertussis toxin, which ADP-ribolysates G proteins; wortmannin, a phosphatidylinositol-3-kinase inhibitor; and genistein, a tyrosine kinase inhibitor, suggesting the involvement of pertussis toxin-sensitive G proteins, phosphatidylinositol-3-kinase, and tyrosine kinase in the signal transduction of eotaxin. Moreover, dexamethasone inhibited ROS from not only untreated eosinophils but also eosinophils treated with eotaxin. CONCLUSION: Eotaxin may play an important role in the pathogenesis of allergic inflammation through eosinophil activation by priming of eosinophil oxidative metabolism, as well as by involvement in selective eosinophil chemotaxis.

Acridines↗
PubMed1996

Detection of C5a receptors on human eosinophils and inhibition of eosinophil effector functions by anti-C5a receptor (CD88) antibodies.

Eosinophils and complement activation are reported to play a crucial role in the pathogenesis of connective tissue diseases. Depositions of antigens and antigen-antibody complexes lead to complement activation with the generation of anaphylatoxins, particularly C5a, which is thought to be responsible for the infiltration and activation of eosinophils in the tissue. Previous studies suggested that the eosinophil C5a receptor differs structurally from the receptor expressed on neutrophils. In this study, we investigated the expression and functional properties of C5a receptors on human eosinophils using the C5a receptor monoclonal antibody S5/1 (anti-CD88 mAb). Flow cytometric analysis demonstrated that the anti-CD88 mAb bound homogeneously on the surface of human eosinophils from nonatopic healthy donors. In addition, no subpopulations with respect to C5a receptor expression were identified in normodense or hypodense eosinophils of patients with hypereosinophilia. Pre-incubation of eosinophils with anti-CD88 specifically inhibited C5a-induced intracellular calcium concentration transients. C5a-induced chemotactic activity of eosinophils was significantly inhibited after pre-incubation of cells with anti-CD88 mAb in a dose-dependent manner. Furthermore, anti-CD88 mAb inhibited dose-dependently the release of reactive oxygen species by eosinophils following stimulation with C5a. Thus, the human eosinophil C5a receptor is homogeneously expressed on normal eosinophils from healthy donors as well as on hypodense and normodense eosinophil subpopulations from patients with hypereosinophilia. Based on the inhibitory effect of the S5/1 mAb on C5a-stimulated eosinophil effector functions, we conclude that a single C5a receptor type exists on human eosinophils. In addition, the inhibitory effect of the S5/1 mAb on C5a functions may enable a new experimental approach to the treatment of diseases that have been associated with C5a-mediated activation.

Antibodies, Monoclonal↗