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Apoptotic response of eosinophils in chronic eosinophilic pneumonia.

To clarify the pathogenesis of chronic eosinophilic pneumonia (CEP), the apoptosis of eosinophils from bronchoalveolar lavage (BAL-Eos) was compared with that of eosinophils from peripheral blood (PB-Eos) in six cases of CEP. The survival rate of eosinophils and the percentage of apoptotic cells of both types of eosinophils were examined, and the effects of interleukin 5 (IL-5) were evaluated. The role of Fas expression in apoptosis of these eosinophils was also studied. The survival rate of BAL-Eos on the third day of culture was significantly higher than that of PB-Eos (p < 0.01). This was associated with a lower proportion of apoptotic cells in BAL-Eos than in PB-Eos; the percentages of apoptotic cells in PB-Eos and BAL-Eos after 24 h of incubation were 21.7 +/- 3.4% and 10.6 +/- 1.7% respectively. IL-5 suppressed apoptosis and increased the survival rate of both PB-Eos and BAL-Eos. It was found that the apoptotic character of BAL-Eos differed from that of PB-Eos in at least three ways. Firstly, the positive rate of Fas expression on PB-Eos was increased after 24 h of incubation, whereas that on BAL-Eos did not change. Secondly, the expression of Fas on PB-Eos was suppressed by IL-5 (18.5 +/- 4.2% - 8.3 +/- 3.2%, p < 0.05), whereas IL-5 failed to suppress Fas expression on BAL-Eos (3.3 +/- 1.6% - 3.6 +/- 1.0%). Lastly, binding of antibody to Fas antigen induced apoptosis of PB-Eos, but not of BAL-Eos. These data suggested that Fas seemed to be involved in the apoptosis of PB-Eos, whereas BAL-Eos were Fas-resistant in chronic eosinophilic pneumonia. In conclusion, apoptosis of eosinophils might be suppressed by proinflammatory cytokines such as IL-5 leading to their accumulation in the lung. Chronic stimulation of eosinophils in the alveolar space with IL-5 may play a crucial role chronic eosinophilic disorders.

Adult↗

CD4+ T cell and eosinophil adhesion is mediated by specific ICAM-3 ligation and results in eosinophil activation.

T cells and eosinophils, which are found in close proximity in asthmatic lungs, express many surface receptors that are counterligands. These data suggest that direct interactions between these cell types could play an important role in regulating airway inflammation in asthma. We examined the effect of selective adhesion between counterligands on human eosinophils and CD4+ T cells to determine 1) the existence of specific adhesive interactions and 2) if augmented specific adhesion to CD4+ T cells also caused augmented secretion of leukotriene C4 (LTC4) from eosinophils. A new method for binding of human CD4+ T cells to microwell plates was developed, which allowed for specific quantitative assessment of eosinophil adhesion to individual CD4+ T cells in culture. Adhesion of CD4+ T cells to eosinophils was minimal in unstimulated cells but increased after activation of T cells by PMA. Augmented adhesion was regulated substantially through binding of ICAM-3 and only minimally by ICAM-1. We further evaluated whether this specific adhesion up-regulated stimulated secretion of LTC4 from eosinophils. Adhesion with CD4+ T cells augmented eosinophil secretion of LTC4 caused by FMLP plus cytochalasin. Blockade of ICAM-3, as well as ICAM-1, inhibited completely the augmented secretion of eosinophil LTC4. We demonstrate that eosinophils and CD4+ T cells are capable of ligand-specific adhesion that is mediated predominantly by ICAM-3 ligation and that this binding causes augmented eosinophil secretion.

Adjuvants, Immunologic↗

Establishment of a human T-cell line constitutively producing several eosinophil chemotactic lymphokines and their functional heterogeneity on eosinophils.

We established a T-cell line, STO-2, by human T-cell lymphoma-leukemia virus-induced transformation of normal human T cells. Partial purification with isoelectric electrophoresis revealed that STO-2 liberated several eosinophil chemotactic factors (ECF) for eosinophils from healthy individuals with different isoelectric point of PI5, PI6, PI7, PI8, and PI9. Molecular weight of all the ECF was about 30,000 to 45,000. None of the ECF except ECF-PI5 was suppressed when they were incubated with monoclonal antibodies against IL-3, IL-5, and GM-CSF together, suggesting that ECF activity of ECF-PI5 is mainly comprised of IL-3, IL-5, and GM-CSF. ECF-PI5, PI6, and PI7 also exhibited enhancing activity on ex vivo eosinophil survival whereas ECF-PI8 and PI9 failed. Expression of Fc epsilon receptor II on eosinophils was potentiated by ECF-PI6 and ECF-PI7. In contrast, expression of Fc gamma receptor III was potentiated by ECF-PI7, ECF-PI8, and ECF-PI9. ECF-PI6 could also change an eosinophilic cell line, EOL-1, to eosinophilic granule-positive cells, whereas the rest of ECF failed. The above results suggested that eosinophils attracted by an ECF exhibit their biological functions, which differ from those of eosinophils attracted by other ECF. In further experiments, the chemotactic response of eosinophils from patients with eosinophilia was compared to that of eosinophils from healthy individuals.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Line, Transformed↗

Effects of IFN on human eosinophils in comparison with other cytokines. A novel class of eosinophil activators with delayed onset of action.

Extracellular killing is regarded as one of the main functions of eosinophils. Therefore, a cytotoxicity assay against antibody-coated Daudi-lymphoma cells was established to measure cytokine effects on peripheral blood eosinophils from healthy volunteers. Optimal time of exposure to cytokines and half optimal concentrations (EC50) were determined and the capability of various cytokines to enhance cytotoxicity of eosinophils was compared. Thus, after 24 h with cytokine, the highest activation of eosinophils was observed with recombinant human rhIFN-gamma (EC50 = 0.2 U/ml), followed by the known activators of eosinophils recombinant human granulocyte/macrophage CSF (rhGM-CSF), rhIL-3, and murine IL-5 (mIL-5). rhIFN-alpha and natural human IFN-beta (nhIFN-beta) enhanced cytotoxicity as well. On the other hand, in short term assays, eosinophils were not stimulated by IFN and the strongest stimulator was rhGM-CSF (EC50 = 0.2 U/ml), followed by rhIL-3, mIL-5, rhTNF, and rhIL-4. With rhTNF-alpha enhancement was more pronounced on freshly isolated eosinophils (EC50 = 0.6 U/ml) and declined with time. No significant stimulation was detected with rhG-CSF, rhIL-1 beta, rhIL-2, rhIL-6, and rhIL-8. On neutrophils, rhIL-8 enhanced cytotoxicity, but the stimulation was weak in relation to other neutrophil activators. Studies on the mechanism of cytotoxic activity revealed that cytotoxicity required opsonization of targets with specific antibody. FMF analysis was performed demonstrating that freshly isolated eosinophils express Fc-gamma RII (CD32), small amounts of Fc-gamma RIII (CD16), but not Fc-gamma RI (CD64). In experiments with blocking antibodies to Fc-gamma R cytotoxicity was restricted to Fc-gamma RII. Expression of Fc-gamma RII was not enhanced by rhGM-CSF, rhTNF-alpha, and mIL-5, but a significant increase in the number of positive cells was observed after incubation with rhIFN-gamma for 24 h (p less than 0.05). In addition, enhanced viability of eosinophils was observed when cultured in the presence of rhIFN-gamma, rhIFN-alpha, rhGM-CSF, and rhTNF-alpha, but not of rhG-CSF and rhIL-2. Thus, IFN appear to be another class of activators of eosinophils, characterized by their delayed type of action.

Antibody-Dependent Cell Cytotoxicity↗

Density heterogeneity of eosinophil leucocytes: induction of hypodense eosinophils by platelet-activating factor.

We have examined the induction of hypodense eosinophils by platelet-activating factor (PAF), a mediator which may be involved in eosinophil activation in allergic diseases. Guinea-pig eosinophils were incubated with buffer or PAF and applied to continuous Percoll density gradients. Cellular density ranged from 1.0142 to 1.1369 g/ml. Peak eosinophil density in control was 1.0887 +/- 0.0008 g/ml (mean +/- SEM), and 91.1 +/- 1.4% of eosinophils were distributed between 1.0810 and 1.1000 g/ml. Preincubation of eosinophils with PAF(10(-7) M) resulted in a time-dependent and non-cytolytic increase of the number of hypodense eosinophils, with peak densities after incubation for 1 hr and 2 hr of 1.0834 +/- 0.0014 (n = 4, P less than 0.05) and 1.0755 +/- 0.0007 g/ml (n = 6, P less than 0.01), respectively. After incubation for 2 hr, 82.0 +/- 4.9% (n = 6) eosinophils showed a density lower than 1.080 g/ml. Lyso-PAF, the inactive precursor and metabolite of PAF, at a concentration of 10(-7) M had no effect on cell density. The specific PAF receptor antagonist WEB 2086 (10(-6) M) inhibited the PAF-induced density shift by 87.0 +/- 5.3%. Our results demonstrate that a single mediator is able to induce the formation of hypodense eosinophils. We conclude that the appearance of hypodense eosinophils in allergic diseases such as asthma may occur, at least in part, in response to inflammatory mediators which activate these cells.

Animals↗

Transformation of prostaglandin D2 to isomeric prostaglandin F2 compounds by human eosinophils. A potential mast cell-eosinophil interaction.

PGD2 undergoes extensive isomerization in vivo followed by metabolism by 11-ketoreductase to yield a family of biologically active isomeric PGF2 compounds, including 9, alpha 11 beta-PGF2. Because immunologically activated human mast cells produce substantial quantities of PGD2 and eosinophils accumulate around mast cells at sites of immediate hypersensitivity reactions, the ability of eosinophils to metabolize PGD2 was investigated. Purified human circulating eosinophils from four different donors transformed PGD2 to 9, alpha 11 beta-PGF2 and 12-epi-9 alpha, 11 beta-PGF2 in a time- and concentration-dependent manner. The formation of these compounds increased rapidly during the first 30 min of incubation of eosinophils with PGD2 and tended to plateau at approximately 2 h. Detection and quantification of the formation of 9 beta,11 beta-PGF2 and its 12-epi isomer was accomplished by a negative ion chemical ionization gas chromatography/mass spectrometry assay. On one occasion, eosinophils from one donor also transformed PGD2 to two additional isomeric PGF2 compounds, the stereochemical structures of which were not identified. The ability of eosinophils to produce PGD2 was then investigated. After stimulation with 2 microM A23187, the major cyclooxygenase product formed was thromboxane B2 (2247 pg/10(6) eosinophils) whereas only small quantities of PGD2 were produced (50 pg/10(6) eosinophils). Inasmuch as PGF2 compounds can exert biologic actions that differ from those of PGD2, this ability of eosinophils to transform PGD2 to PGF2 compounds could alter the local biologic effects of PGD2 released from adjacent mast cells and thus may represent a physiologically relevant mast cell-eosinophil interaction.

6-Ketoprostaglandin F1 alpha↗

Asthma in children less than 5 years of age: eosinophils and serum levels of the eosinophil proteins ECP and EPX in relation to atopy and symptoms.

Children less than 5 years of age with asthma were assessed for total eosinophil counts and serum levels of the eosinophil proteins, eosinophil cationic protein (ECP) and eosinophil protein X (EPX), to determine whether these measurements would reflect eosinophilic inflammation in the airways. Initially 27 symptomatic patients, 14 atopic and 13 nonatopic were investigated. They had a mean age of 1.8 years and had never been treated with inhaled steroid and had not received Intal for 2 weeks prior to the assessment. The 14 atopic patients proved to have higher mean total eosinophil counts and serum levels of ECP and EPX than the 13 non-atopic patients (eosinophil counts 0.63 x 10(9)/l vs 0.26 x 10(9)/l, P < 0.001; ECP 36.9 micrograms/l vs 10.8 micrograms/l, P < 0.001; EPX 69.0 micrograms/l vs 19.6 micrograms/l, P < 0.01). Thirteen of these patients required treatment with daily doses of inhaled steroid and 11 had a repeat assessment (seven atopic and four non-atopic). The mean serum ECP of the seven atopic patients had fallen significantly (40.6 to 22.9, P < 0.05) while the total eosinophil counts did not. These results suggest a difference in numbers and activity of eosinophils in atopic compared with non-atopic asthma in young children. To determine whether the results were influenced by treatment with inhaled steroids, 31 patients who were being treated with daily inhaled steroid underwent assessment when they were symptomatic (22 samples) or asymptomatic (19 samples). Of the 31 patients, 11 were atopic and 20 non-atopic.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗

Eosinophils, eosinophil ribonucleases, and their role in host defense against respiratory virus pathogens.

Eosinophils remain among the most enigmatic of cells, as our appreciation of their detrimental activities--e.g., asthma and allergic disease--far outweighs our understanding of their beneficial effects. Among the major secretory effector proteins of eosinophils are the ribonucleases eosinophil-derived neurotoxin (EDN) and eosinophil cationic protein (ECP) in primates and their orthologs, the eosinophil-associated ribonucleases (EARs) in rodents. The rapid diversification observed among these ribonucleases suggested that the ultimate target(s) might be similarly efficient at generating sequence diversity while maintaining an unalterable susceptibility to ribonucleolytic cleavage. This has prompted us to consider a role for these proteins and by extension, for eosinophils, in host defense against single-stranded RNA virus pathogens. We detail our studies of the antiviral activity of eosinophils and eosinophil ribonucleases against respiratory syncytial virus (RSV) in vitro and the related, natural rodent pathogen, pneumonia virus of mice (PVM), in vivo, and consider the possibility that antiviral host defense and the dysregulated responses leading to asthma represent opposing sides of an eosinophil-mediated double-edged sword.

Animals↗

Eosinophil Function in Eosinophil-associated Gastrointestinal Disorders.

Eosinophil-associated gastrointestinal disorders (EGIDs) are characterized by a rich eosinophilic inflammation of the gastrointestinal tract in the absence of known causes for eosinophilia or other gastrointestinal disorders. These disorders include eosinophilic esophagitis, eosinophilic gastritis, eosinophilic gastroenteritis, eosinophilic enteritis, and eosinophilic colitis, and are being recognized with increasing frequency. Clinical studies suggest that eosinophils have a pathogenic role in EGID; however, the function of eosinophils in these disorders remains an enigma. In this review, we briefly describe the clinical features of EGID of the esophagus, small bowel, and colon. We summarize recent experimental analysis examining the underlying contribution of eosinophils to disease pathogenesis and discuss possible therapeutic approaches for the treatment of these diverse diseases.

Animals↗

[Eosinophilic bronchitis without asthma--an additional rare cause for chronic persistent cough (CPC)? A 30-year old patient with severe CPC due to eosinophilic bronchitis without asthma or hyperreactivity].

In non-smokers the underlying causes for chronic persistent cough (CPC) e.g. chronic cough without diagnostic chest X-ray or pulmonary function test--are usually as follows: several common upper airways diseases, bronchial (cough type) asthma, gastrooesophageal reflux or treatment with an ACE (angiotensin converting enzyme)--inhibitor. In 10% of CPC however the cause remains uncertain. We report a 30 year old non-smoker with severe coughing and repeated vomiting for two months. No laboratory or technical data could be collected suggestive of a common cause of CPC: Upper airways disease, bronchial flow limitation or hyperresponsiveness, ACE inhibitor medication, B. pertussis infection, gastrooesophageal reflux disease (by 24 hours pH-probe) were ruled out. Fiberbronchoscopic findings remained unremarkable, except for the bronchial biopsy specimen, which showed moderate eosinophilic inflammation of the mucosa and marked thickening of the subepithelial layer. Since the cough was non-productive, sputum induction with 3 ml nebulised 3% NaCl solution was performed. 28% of the granulocytes were eosinophil stained. A low quality morning sputum (< 1 ml) showed 21% eosinophilia. Thus, the diagnosis of eosinophilic bronchitis was established. 400 micrograms budesonide dry powder inhalations b.i.d. for one week resolved the cough, treatment was stopped after three weeks. No recurrence was seen two months later. Both the cough type asthma and the eosinophilic bronchitis could represent a form fruste of classical bronchial asthma beyond wheezing or dyspnoea, but with the common main symptom: cough. Since hyperresponsiveness and cough are phenotypic hallmarks of cough variant asthma, in eosinophilic bronchitis--beside cough--another two features of asthma are present: eosinophilic inflammation of the mucosa along with sputum eosinophilia and subepithelial layer thickening. Not surprisingly, eosinophilic bronchial inflammation could be shown in patients with cough variant asthma as well, who--up to 56% during a four year-period--develop classic asthma. The long-term outcome of eosinophilic bronchitis is not known, however. Thus, asthma, cough variant asthma and cough due to eosinophilic bronchitis can mirror different phenotypes or phases of the same entity. CPC due to either the cough type asthma or the eosinophilic bronchitis is like asthma fast responding to inhalative steroids. (Induced) sputum staining should be added to the diagnostic armamentarium of CPC.

Adult↗

Increased interleukin-5 levels in bronchoalveolar lavage fluid is a major factor for eosinophil accumulation in acute eosinophilic pneumonia.

BACKGROUND: Increased interleukin-5 (IL-5) levels have been reported in bronchoalveolar lavage fluid (BALF) from patients with acute eosinophilic pneumonia (AEP); however, it still remains to be determined whether IL-5 is responsible for the eosinophil accumulation in the lung. OBJECTIVE: We examined the effect of antibodies against cytokines on eosinophil chemotaxis induced by BALF from AEP patients to identify factors responsible for eosinophil accumulation. METHODS: We measured a series of specific cytokines, including IL-3, IL-4, IL-5, IL-6, IL-8, GM-CSF, RANTES, MCP-1, MIP-1alpha and eotaxin, in the BALF from 4 patients with AEP. BALF from 4 patients with chronic eosinophilic pneumonia (CEP) and 13 patients with non-eosinophilic interstitial lung diseases (ILD) were examined as controls. The eosinophil chemotactic activity in the BALF was examined using tissue culture insert furnished with a polycarbonate membrane. RESULTS: The total protein content in BALF from patients with AEP was extremely elevated. Even after standardization with protein concentration, IL-5 levels in AEP patients were significantly higher than those in CEP and ILD. IL-3 and chemokines were rather lower in the AEP group than in the CEP and ILD groups. In AEP BALF, anti-IL-5 neutralizing antibody significantly inhibited eosinophil chemotaxis. Antibodies against IL-3, GM-CSF, and IL-8 did not affect the eosinophil migration. CONCLUSION: These findings suggest that locally produced IL-5 plays an important role in eosinophil accumulation of AEP.

Acute Disease↗

Skin reactivity to vasomotor agents in non-eosinophilic and eosinophilic non-allergic rhinitis.

The aim of this prospective study was to examine skin reactivity to four vasomotor agents and to determine whether non-eosinophilic rhinitis patients differ from patients with eosinophilic rhinitis. Nasal cytology enabled us to classify 74 rhinitis patients into a non-eosinophilic (n = 63) and an eosinophilic group (n = 11). Skin reactivity to intradermal tests with papaverine, metacholine, histamine and compound 48/80 was measured. No significant difference for papaverine, metacholine, histamine and compound 48/80, singly, was found between the non-eosinophilic and eosinophilic group. The frequency of the total pathological skin reactivity to vasomotor agents, singly and in combinations, was greater in the eosinophilic (91 per cent) then in the non-eosinophilic group (78 per cent) but intergroup difference was not significant. These findings suggest that pathologic skin reactivity to vasomotor agents is a feature of non-eosinophilic as well as eosinophilic non-allergic rhinitis patients and indicate that no difference is noticed in the skin reactivity between these groups.

Adolescent↗

[Peripheral blood eosinophils and serum level of eosinophil cationic protein in asthmatics].

OBJECTIVE: Determine the number of circulating eosinophils and serum eosinophil cationic protein levels in asthmatics, and the relationship between them. METHODS: We studied 26 atopic asthmatics aged 7-16 years divided in two groups according to severity of asthma. Eosinophil counts were obtained by multiplying leukocyte number by eosinophil percent. Serum eosinophil cationic protein levels were determined by fluoroenzymatic method, CAP System, Pharmacia Diagnostics. RESULTS: Asthmatics had eosinophil counts (810 +/- 103/mcl) significantly higher than non atopic children (158 +/- 30/mcl). Mean eosinophil cationic protein levels were higher in severe asthmatics (p < 0,001) and correlated with eosinophil counts. CONCLUSIONS: Serum eosinophil cationic protein levels could be useful in assessing the allergic inflammation and probably reflect the activation of eosinophils.

English Abstract↗

Digestion of the fifth component of complement by eosinophil lysosomal enzymes. Production of eosinophil specific chemotactic activity.

Recently our laboratory has shown that neutrophils contain enzymatic activity within their lysosomal granules which will generate chemotactic activity for neutrophils and tumor cells from the fifth component of complement (C5). We have now expanded this initial observation and have demonstrated that eosinophils can release enzymatic activity from their lysosomal granules upon stimulation with immune complexes or opsoninized zymosan, but not with C5a or synthetic chemotactic peptides. Furthermore, the enzymatic activity released from the eosinophil lysosomal granules can cleave C5 into eosinophil-specific chemotactic activity. The generation of the eosinophil chemotactic activities from C5 is blocked by prior treatment of the eosinophil preparations with a number of protease inhibitors. The eosinophil-derived C5 cleaving activity possesses a pH optimum of 7.2, thus suggesting the enzymatic activity is a neutral protease. The demonstration that enzyme activities derived from eosinophils have the ability to generate eosinophil chemotactic factor(s) from C5 may explain why eosinophils are the predominant inflammatory cell in both nasal polyps and in the nasopharynx and bronchi of patients with allergic conditions such as hay fever and asthma.

Animals↗

Peripheral blood eosinophils from patients with allergic asthma contain increased intracellular eosinophil-derived neurotoxin.

BACKGROUND: One mechanism of the eosinophil's contribution to airway inflammation in asthma is through release of cationic granule proteins to cause airway injury. Differences in either the intracellular concentration of granule proteins or the extent of activated degranulation between eosinophils from healthy patients and those with allergy and asthma could, therefore, relate to fundamental differences in this cell's function. OBJECTIVE: To identify phenotypic differences in eosinophil-derived neurotoxin (EDN) content and release in eosinophils from healthy patients, those with allergy, and those with allergy and asthma. METHODS: Peripheral blood eosinophils were isolated by negative anti-CD16 selection. Total intracellular and cytokine-activated release of EDN protein was measured by radioimmunoassay. EDN mRNA was assessed by real-time PCR. RESULTS: Eosinophils from patients with asthma contained significantly more EDN per cell than comparable cells from healthy patients, those with allergy but without asthma, or those with asthma treated with inhaled corticosteroids, but they had concentrations similar to airway eosinophils isolated from bronchoalveolar lavage fluid 48 hours after segmental bronchoprovocation with allergen. Furthermore, this increased granule protein was reflected in more EDN degranulation by IL-5- or GM-CSF-activated eosinophils when calculated as nanograms of protein secreted but not when calculated as a percentage of total EDN release. Levels of EDN mRNA were similar in all subject groups. CONCLUSIONS: These data suggest that peripheral blood eosinophils from subjects with untreated asthma have increased inflammatory capacity, as reflected by greater intracellular concentrations of EDN.

Adolescent↗

Differentiation of a human eosinophilic leukemic cell line, EoL-1: characterization by the expression of cytokine receptors, adhesion molecules, CD95 and eosinophilic cationic protein (ECP).

Purification of enough eosinophils for the study of allergic inflammation is difficult because eosinophils comprise only a small percentage of circulating leucocytes. A human eosinophilic leukemic cell line, EoL-1, has been considered to be an in vitro eosinophilic model. In the present study, the suitability of EoL-1 cells as an eosinophilic model was further investigated. EoL-1 cells were induced to differentiate by dibutyryl cyclic AMP (dbcAMP). The expression of cell surface cytokines (IL-3, IL-5, GM-CSF) receptors, adhesion molecules (CD49d, CD11b), and CD95 (Fas) was investigated by flow cytometry. Expression of eosinophilic cationic protein (ECP) was determined by fluorescence enzyme immunoassay (FEIA) and reverse transcription-polymerase chain reaction (RT-PCR). EoL-1 cells could be differentiated into eosinophilic vacuole-containing cells by dbcAMP. They were found to express cell surface IL-3 and GM-CSF receptors, CD95 and CD49d. Treatment with dbcAMP could induce the expression of CD11b but decrease the expression of CD95. Anti-CD95 antibody could induce their apoptosis. The differentiation of EoL-1 cells was accompanied by increase in release of ECP into the supernatant and total ECP synthesis. Differentiation of EoL-1 cells also up-regulated the expression of mRNA for ECP and its level was parallel to the total amount of ECP synthesis. By virtue of their expression of haematopoietic cytokines receptors, adhesion molecules, CD95, synthesis and release of ECP, EoL-1 cells are suitable as an in vitro eosinophilic model for studying eosinophilic functions.

Antigens, CD↗

A pathological function for eotaxin and eosinophils in eosinophilic gastrointestinal inflammation.

Although eosinophils have been implicated in the pathogenesis of gastrointestinal disorders, their function has not been established. Using a murine model of oral antigen-induced eosinophil-associated gastrointestinal disease, we report the pathological consequences of eosinophilic inflammation and the involvement of eotaxin and eosinophils. Exposure of mice to enteric-coated antigen promotes an extensive T helper 2-associated eosinophilic inflammatory response involving the esophagus, stomach, small intestine and Peyer's patches as well as the development of gastric dysmotility, gastromegaly and cachexia. Electron microscopy shows eosinophils in proximity to damaged axons, which indicated that eosinophils were mediating a pathologic response. In addition, mice deficient in eotaxin have impaired eosinophil recruitment and are protected from gastromegaly and cachexia. These results establish a critical pathological function for eotaxin and eosinophils in gastrointestinal allergic hypersensitivity.

Administration, Oral↗

Expression of eotaxin, an eosinophil-selective chemokine, parallels eosinophil accumulation in the vesiculobullous stage of incontinentia pigmenti.

Incontinentia pigmenti (IP) is an X-linked dominant genodermatosis primarily affecting female children. The initial vesiculobullous stage of IP is characterized clinically by inflammatory papules, blisters, and pustules, and histopathologically by acanthosis, keratinocyte necrosis, epidermal spongiosis and massive epidermal eosinophil infiltration. The cause of this multisystem disease is attributed to the mutations of an X-linked regulatory gene, termed nuclear factor-kappaB essential modulator (NEMO). The exact mechanism of epidermal eosinophil accumulation has not yet been determined. We explored the possible role of an eosinophil-selective, nuclear factor-kappaB-activated chemokine, eotaxin, in the accumulation of eosinophils in the initial stage of the disease. Monoclonal antibody (6H9) specific for human eotaxin strongly labelled the suprabasal epidermis of IP skin, paralleling the upper epidermal accumulation of eosinophils, but did not label the epidermis of normal skin or lesional skin from patients with other inflammatory skin diseases not characterized by prominent eosinophil accumulation, namely dermatitis herpetiformis and selected cases of atopic dermatitis lacking significant numbers of eosinophils. In addition, endothelial cells in lesional skin of IP also exhibited strong expression of eotaxin, which correlated with perivascular and intravascular eosinophil infiltration. We also examined the in vitro effects on epidermally derived eotaxin of several cytokines that were nuclear factor-kappaB-activated and/or known to induce eotaxin expression. In normal human keratinocytes, proinflammatory cytokines either independently (IL-1alpha) or synergistically (tumour necrosis factor-alpha (TNF-alpha)/ interferon-gamma (IFN-gamma) and TNF-alpha/IL-4) up-regulated eotaxin expression. These studies suggest that release of cytokines during the initial inflammatory stage of IP induces epidermal expression of eotaxin, which may play a role in the epidermal accumulation of eosinophils.

Cells, Cultured↗