Eotaxin in induced sputum of asthmatics: relationship with eosinophils and eosinophil cationic protein in sputum

Molecular characterization of allergic constitution based on network pharmacology and multi-omics analysis methods

The objective of this study was to identify critical pathways associated with allergic constitution. Shared genes among allergic rhinitis (AR), asthma (AA), and atopic dermatitis (AD) were extracted from the GWAS catalog. RNA-seq data of AR, AA, and AD from gene expression omnibus (GEO) database were preprocessed and subjected to differential gene expression analysis. The differentially expressed genes (DEGs) were merged using the Robust Rank Aggregation (RRA) algorithm. Weighted gene co-expression network analysis (WGCNA) was performed to identify modules associated with allergies. Components of Guominkang (GMK) were obtained from 6 databases and activate components were identified by SwissADME website. Utilizing the SwissTarget Prediction, PharmMapper, SymMap, and HERB, the targets of GMK were predicted and subsequently validated using gene chip data from our team previous study. Differentially expressed proteins (DEPs) related to the allergic constitution were also extracted based on a previous study. Pathway enrichment analysis was performed using KOBAS-i on the GWAS, RRA, WGCNA modules, DEPs, and GMK targets. P values from multi-omics datasets were combined by meta-analysis, and Bonferroni correction was applied. The significant pathways were further validated using Gene Set Enrichment Analysis (GSEA) with intervention data of GMK. The GWAS results yielded 172 genes. Four datasets AR1, AA1, AD1, and AD2 were acquired from GSE75011, GSE125916, and GSE184237. The RRA algorithm identified 19 upregulated and 20 downregulated genes. WGCNA identified 5 significant modules, with the blue and turquoise modules displaying a moderate correlation with allergies. By performing network pharmacology analysis, we identified 127 active ingredients of GMK and predicted 618 targets. Validation using gene chip data confirmed 107 GMK targets. Single-omics pathway analysis was conducted using KOBAS-i, and 39 significant pathways were identified across multiple omics datasets. GSEA analysis using GMK intervention data identified 11 of 39 significant pathways as the final key pathways associated with the allergic constitution. Through multi-omics integrated pathway analysis, we identified 11 critical pathways of allergic constitution, including TH1 and TH2 cell differentiation, TLR cascade, and TH17 cell differentiation. Identifying these pathways suggests that the observed alterations at the pathway level may play significant roles in the molecular characteristics of the allergic constitution.

Questioning Cause and Effect: Children with Severe Asthma Exhibit High Levels of Inflammatory Biomarkers Including Beta-Hexosaminidase, but Low Levels of Vitamin A and Immunoglobulins

Asthma affects over 8% of the pediatric population in the United States, and Memphis, Tennessee has been labeled an asthma capital. Plasma samples were analyzed for biomarker profiles from 95 children with severe asthma and 47 age-matched, hospitalized nonasthmatic controls at Le Bonheur Children's Hospital in Memphis, where over 4000 asthmatics are cared for annually. Asthmatics exhibited significantly higher levels of periostin, surfactant protein D, receptor for advanced glycation end products and β-hexosaminidase compared to controls. Children with severe asthma had lower levels of IgG1, IgG2 and IgA, and higher levels of IgE compared to controls, and approximately half of asthmatics exhibited IgG1 levels that were below age-specific norms. Vitamin A levels, measured by the surrogate retinol-binding protein, were insufficient or deficient in most asthmatic children, and correlated positively with IgG1. Which came first, asthma status or low levels of vitamin A and immunoglobulins? It is likely that inflammatory disease and immunosuppressive drugs contributed to a reduction in vitamin A and immunoglobulin levels. However, a nonmutually exclusive hypothesis is that low dietary vitamin A caused reductions in immune function and rendered children vulnerable to respiratory disease and consequent asthma pathogenesis. Continued attention to nutrition in combination with the biomarker profile is recommended to prevent and treat asthma in vulnerable children.

Regulation of Eosinophil and Group 2 Innate Lymphoid Cell Trafficking in Asthma

Asthma is an inflammatory disease usually characterized by increased Type 2 cytokines and by an infiltration of eosinophils to the airways. While the production of Type 2 cytokines has been associated with T_H2 lymphocytes, increasing evidence indicates that group 2 innate lymphoid cells (ILC2) play an important role in the production of the Type 2 cytokines interleukin (IL)-5 and IL-13, which likely amplifies the recruitment of eosinophils from the blood to the airways. In that regard, recent asthma treatments have been focusing on blocking Type 2 cytokines, notably IL-4, IL-5, and IL-13. These treatments mainly result in decreased blood or sputum eosinophil counts as well as decreased asthma symptoms. This supports that therapies blocking eosinophil recruitment and activation are valuable tools in the management of asthma and its severity. Herein, we review the mechanisms involved in eosinophil and ILC2 recruitment to the airways, with an emphasis on eotaxins, other chemokines as well as their receptors. We also discuss the involvement of other chemoattractants, notably the bioactive lipids 5-oxo-eicosatetraenoic acid, prostaglandin D₂, and 2-arachidonoyl-glycerol. Given that eosinophil biology differs between human and mice, we also highlight and discuss their responsiveness toward the different eosinophil chemoattractants.

Monoclonal antibody therapy for the treatment of asthma and chronic obstructive pulmonary disease with eosinophilic inflammation

Eosinophils have been linked with asthma for more than a century, but their role has been unclear. This review discusses the roles of eosinophils in asthma and chronic obstructive pulmonary disease (COPD) and describes therapeutic antibodies that affect eosinophilia. The aims of pharmacologic treatments for pulmonary conditions are to reduce symptoms, slow decline or improve lung function, and reduce the frequency and severity of exacerbations. Inhaled corticosteroids (ICS) are important in managing symptoms and exacerbations in asthma and COPD. However, control with these agents is often suboptimal, especially for patients with severe disease. Recently, new biologics that target eosinophilic inflammation, used as adjunctive therapy to corticosteroids, have proven beneficial and support a pivotal role for eosinophils in the pathology of asthma. Nucala® (mepolizumab; anti-interleukin [IL]-5) and Cinquair® (reslizumab; anti-IL-5), the second and third biologics approved, respectively, for the treatment of asthma, exemplifies these new treatment options. Emerging evidence suggests that eosinophils may contribute to exacerbations and possibly to lung function decline for a subset of patients with COPD. Here we describe the pharmacology of therapeutic antibodies inhibiting IL-5 or targeting the IL-5 receptor, as well as other cytokines contributing to eosinophilic inflammation. We discuss their roles as adjuncts to conventional therapeutic approaches, especially ICS therapy, when disease is suboptimally controlled. These agents have achieved a place in the therapeutic armamentarium for asthma and COPD and will deepen our understanding of the pathogenic role of eosinophils.

Neolignans from the Arils of Myristica fragrans as Potent Antagonists of CC Chemokine Receptor 3

CC chemokine receptor 3 (CCR3) is expressed selectively in eosinophils, basophils, and some Th2 cells and plays a major role in allergic diseases. A methanol extract from the arils of Myristica fragrans inhibited CC chemokine ligand 11-induced chemotaxis in CCR3-expressing L1.2 cells at 100 μg/mL. From this extract, eight new neolignans, maceneolignans A-H (1-8), were isolated, and their stereostructures were elucidated from their spectroscopic values and chemical properties. Of those constituents, compounds 1, 4, 6, and 8 and (+)-erythro-(7S,8R)-Δ(8')-7-hydroxy-3,4-methylenedioxy-3',5'-dimethoxy-8-O-4'-neolignan (11), (-)-(8R)-Δ(8')-3,4-methylenedioxy-3',5'-dimethoxy-8-O-4'-neolignan (17), (+)-licarin A (20), nectandrin B (25), verrucosin (26), and myristicin (27) inhibited CCR3-mediated chemotaxis at a concentration of 1 μM. Among them, 1 (EC50 1.6 μM), 6 (1.5 μM), and 8 (1.4 μM) showed relatively strong activities, which were comparable to that of a synthetic CCR3 selective antagonist, SB328437 (0.78 μM).

Specific allergen immunotherapy: effect on IgE, IgG4 and chemokines in patients with allergic rhinitis

BACKGROUND

Allergen-specific immunotherapy (SIT) is considered as the most effective treatment for Immunoglobulin E (IgE)-mediated allergies. However, how specific immunotherapy attenuates allergic responses is still not clear, but could potentially involve cytokines as well as IgG4-mediated responses. Based on the role of chemokines in IgE-mediated inflammation, we examined the SIT-induced chemokine response in patients with allergic rhinitis.

METHODS

We included 35 patients with allergic rhinitis; 20 patients received SIT and 15 patients were not treated with specific immunotherapy. The patients were followed for 3 years. Blood samples were collected before SIT and 3, 5, 7 and 21 weeks and 1, 2 and 3 years after the start of therapy. Total IgE, specific IgE, IgG4 and chemokine levels were assessed.

RESULTS

Our main findings were: (i) SIT was associated with an early increase in total and specific IgE during the first 7 weeks, with a subsequent decline, accompanied by a marked increase in specific IgG4 when IgE started to decline; (ii) these SIT-induced responses were accompanied by and in some degree correlated with increased plasma concentrations of the chemokines, monocyte chemoattractant protein (MCP)-1, and eotaxin; and (iii) within the SIT group, these correlations with chemokines were restricted to IgE and IgG4 against birch tree pollen.

CONCLUSION

Our findings further support a role for IgG4-mediated mechanisms in the beneficial effects of SIT in patients with allergic rhinitis (AR) and that increased levels of certain chemokines also could be of importance for the effect of such therapy.

Deciphering Asthma Biomarkers with Protein Profiling Technology

Asthma is a chronic inflammatory disease of the airways, resulting in bronchial hyperresponsiveness with every allergen exposure. It is now clear that asthma is not a single disease, but rather a multifaceted syndrome that results from a variety of biologic mechanisms. Asthma is further problematic given that the disease consists of many variants, each with its own etiologic and pathophysiologic factors, including different cellular responses and inflammatory phenotypes. These facets make the rapid and accurate diagnosis (not to mention treatments) of asthma extremely difficult. Protein biomarkers can serve as powerful detection tools in both clinical and basic research applications. Recent endeavors from biomedical researchers have developed technical platforms, such as cytokine antibody arrays, that have been employed and used to further the global analysis of asthma biomarker studies. In this review, we discuss potential asthma biomarkers involved in the pathophysiologic process and eventual pathogenesis of asthma, how these biomarkers are being utilized, and how further testing methods might help improve the diagnosis and treatment strain that current asthma patients suffer.

CCL11 as a potential diagnostic marker for asthma?

OBJECTIVE

Asthma is an inflammatory airway disease characterized by airway eosinophilia, in which CCL11 (eotaxin) plays a crucial role. The aim of study is to determine the elevation of CCL11 levels in bronchoalveolar lavage fluid (BALF), blood, exhaled breath condensate (EBC) and sputum in asthma patients and to identify which medium yields the most significant change in CCL11 level.

METHODS

The databases of PubMed, Embase and Cochrane Centre Register of Controlled Trials were systematically searched from inception to September 2013. Controlled clinical trials that focused on CCL11 concentrations in asthma patients and controls, and their correlations with other asthma indicators were obtained. Data were analysed using Stata 12.0.

RESULTS

Thirty studies were included in this investigation. CCL11 levels in blood, EBC and sputum were significantly higher in asthma patients than in healthy subjects. Sputum CCL11 concentrations were significantly elevated in unstable asthma patients versus stable asthma patients and in uncontrolled asthma patients versus partially controlled asthma patients. CCL11 levels in sputum and blood were negatively correlated with the lung function as measured by FEV1% predicted, and were positively correlated with BALF, EBC and sputum eosinophil counts. Similarly, CCL11 concentrations were positively correlated with eosinophil cationic protein in EBC, blood and sputum as well as with interleukin-5 in sputum and fractional exhaled nitric oxide in EBC. Steroid treatment had no significant effect on CCL11 levels.

CONCLUSIONS

CCL11 is a potentially useful biomarker for the diagnosis and assessment of asthma severity and control, especially in sputum. CCL11 is crucial in eosinophil chemoattraction and activation in asthma pathogenesis. Further studies using anti-CCL11 approaches are needed to confirm a role for CCL11 in asthma pathogenesis particularly in patients with more severe disease.

From airway inflammation to inflammatory bowel disease: eotaxin-1, a key regulator of intestinal inflammation

Eotaxin-1 (CCL-11) is a potent eosinophil chemoattractant that is considered a major contributor to tissue eosinophilia. Elevated eotaxin-1 levels have been described in various pathologic conditions, ranging from airway inflammation, to Hodgkin lymphoma, obesity and coronary artery disease. The main receptor for eotaxin-1 is CCR3; however, recent evidence indicates that eotaxin-1 may also bind to other receptors expressed by various cell types, suggesting a more widespread regulatory role for eotaxin-1 beyond the recruitment of eosinophils. Eotaxin-1 is also strongly associated with various gastrointestinal (GI) disorders. Although the etiology of inflammatory bowel disease (IBD) is still unknown, eotaxin-1 may play a key role in the development of mucosal inflammation. In this review, we summarize the biological context and effects of eotaxin-1, as well as its potential role as a therapeutic target, with a special focus on gastrointestinal inflammation.

Recent progress in the development of antagonists to the chemokine receptors CCR3 and CCR4

INTRODUCTION

The chemokine receptors CCR3 and CCR4 have been shown to be important therapeutic targets for the treatment of a variety of diseases. Although only two chemokine receptor inhibitors have been approved so far, there are numerous compounds that are in various stages of development.

AREAS COVERED

In this review article, the authors provide an update on the progress made in the identification of antagonists against the chemokine receptors CCR3 and CCR4 from 2009 to the present. The rationale of writing this review article is to cover the most important approaches to identifying antagonists to these two receptors, which could prove to be useful therapeutics in treating proinflammatory diseases.

EXPERT OPINION

Pharmaceutical companies have expended a considerable amount of money and effort to identify potent inhibitors of CCR3 and CCR4 for the treatment of asthma and atopic diseases. Although a variety of compounds have been described and several have progressed into the clinic, none have so far made it as approved drugs. There are, however, novel approaches such as mogamulizumab, a monoclonal antibody to CCR4 currently is in clinical trials for cancer and ASM8, an antisense nucleotide to CCR3, which is in Phase II clinical trials for asthma that might still prove to be successful new therapeutics.

Serum levels of the CC chemokines CCL2, CCL5, and CCL11 in food allergic children with different clinical manifestations

Food allergies (FA) are frequent in 8 % of children under 3 years old and approximately 2 % of adults. Chemokine are involved in various allergies such as FA. The present study was aimed to determine CCL2, CCL5, and CCL11 levels in FA. The study population of this cross-sectional study contained 63 patients suffering from FA and 100 healthy controls. Concentrations of CCL2, CCL5, CCL11, and IgE were measured by enzyme-linked immunosorbent assay (ELISA). Eosinophils were counted using Casy Ι cell counter + analyzer system model SCAREF system GmbH. Differences were considered significant at P < 0.05. Current results showed that FA patients had significantly elevated numbers of circulating periphery eosinophils than the disease-free controls. Serum IgE levels in FA patients were also higher than controls. We also showed that serum levels of CCL2 and CCL11 were significantly enhanced in FA patients compared to control but CCL5 was not detectable. Results of present study revealed that both CCL2 and CCL11 were more elevated in FA children suffering from anaphylaxis and urticaria than bronchial asthma and atopic dermatitis. These results also indicated that more increased levels of CCL2 and CCL11 were observed following consumption of cow's milk and pistachio nuts. Overall, findings of the present study proposed that serum levels of CCL2 and CCL11 are elevated in FA and these may be considered as useful parameters in diagnosis of disorder. It is also possible to design treatments on the basis of blocking of chemokines expression by application of antibodies against them to overcome allergic complications in patients suffering from FA.

The C-C motif chemokine ligands CCL5, CCL11, and CCL24 induce the migration of circulating fibrocytes from patients with severe asthma

The C-C motif chemokine ligand 5 (CCL5), CCL11, and CCL24 are involved in the pathogenesis of asthma, and their function is mainly associated with the airway recruitment of eosinophils. This study tested their ability to induce the migration of circulating fibrocytes, which may contribute to the development of irreversible airflow obstruction in severe asthma. The sputum fluid phase (SFP) from patients with severe/treatment-refractory asthma (PwSA) contained elevated concentrations of CCL5, CCL11, and CCL24 in comparison with the SFP from patients with non-severe/treatment-responsive asthma (PwNSA). The circulating fibrocytes from PwSA expressed the receptors for these chemokines at increased levels and migrated in response to recombinant CCL5, CCL11, and CCL24. The SFP from PwSA induced the migration of autologous fibrocytes, and its activity was significantly attenuated by neutralization of endogenous CCL5, CCL11, and CCL24. These findings suggest that CCL5, CCL11, and CCL24 may contribute to the airway recruitment of fibrocytes in severe asthma.

Nasal eosinophilia as a marker for allergic rhinitis: a controlled study of 50 patients

Eosinophils are the principal effector cells involved in the pathogenesis of allergic inflammation. We conducted a study to investigate the validity of the nasal smear examination for detecting eosinophilia in patients with allergic rhinitis. Our study group was made up of 50 patients with allergic rhinitis and 50 age- and sex-matched controls without allergic rhinitis. Smears were obtained from nasal secretions in both groups and then fixed, stained, and studied under light microscopy. Statistical analysis revealed that the odds ratio for eosinophilia positivity in nasal smears in the rhinitis group was 25.61 with a 95% confidence interval of 8 to 78. The sensitivity, specificity, positive predictive value, and negative predictive value of this test were 74, 90, 88, and 77%, respectively. We conclude that the nasal eosinophilia test is highly specific and moderately sensitive in diagnosing allergic rhinitis, and that it therefore can be used as an easy, noninvasive, and inexpensive procedure for screening patients and for conducting epidemiologic studies of this disorder.

Targeting chemokine receptors in allergic disease

The directed migration of cells in response to chemical cues is known as chemoattraction, and plays a key role in the temporal and spatial positioning of cells in lower- and higher-order life forms. Key molecules in this process are the chemotactic cytokines, or chemokines, which, in humans, constitute a family of approx. 40 molecules. Chemokines exert their effects by binding to specific GPCRs (G-protein-coupled receptors) which are present on a wide variety of mature cells and their progenitors, notably leucocytes. The inappropriate or excessive generation of chemokines is a key component of the inflammatory response observed in several clinically important diseases, notably allergic diseases such as asthma. Consequently, much time and effort has been directed towards understanding which chemokine receptors and ligands are important in the allergic response with a view to therapeutic intervention. Such strategies can take several forms, although, as the superfamily of GPCRs has historically proved amenable to blockade by small molecules, the development of specific antagonists has been has been a major focus of several groups. In the present review, I detail the roles of chemokines and their receptors in allergic disease and also highlight current progress in the development of relevant chemokine receptor antagonists.

Sputum dipalmitoylphosphatidylcholine level as a novel airway inflammatory marker in asthmatic children

INTRODUCTION

Pulmonary surfactant is a unique mixture of lipids and surfactant-specific proteins. Phosphatidylcholine comprises almost 80% of the total surfactant lipids, about half of which is dipalmitoylphosphatidylcholine (DPPC). Alteration of surfactant composition and function is documented with various airway or lung parenchyma disorders.

OBJECTIVE

To assess sputum concentration of DPPC as a major component of airways surfactant in asthmatic children compared to conventional airway inflammatory markers.

METHODS

This case control study included 68 well-known asthmatic children of different grades of severity and 20 age- and sex-matched normal children as controls. All children were subjected to thorough clinical examination, pulmonary function tests, sputum induction and processing for cytology, DPPC level and eosinophil cationic protein (ECP) level assessment.

RESULTS

Elevated DPPC levels were evident in all sputum samples of asthmatic children (mean value 626.6 +/- 189.7 mcg/mL) compared to controls (mean value 49.3 +/- 20.1 mcg/mL). Significant negative correlations (r = -0.83, -0.752 and -0.384) were found between asthmatics sputum DPPC levels and pulmonary function test parameters [% of forced expiratory volume in first second, % of forced vital capacity (FVC) and forced expiratory flow rate over 25%-75% part of FVC], respectively. Meanwhile, significant positive correlations were evident between asthmatics sputum DPPC levels and the sputum inflammatory cells and their sputum ECP levels.

CONCLUSION

Elevated DPPC levels are evident in induced sputum of all asthmatic children and they are significantly related to sputum ECP levels and pulmonary function test parameters. Nevertheless, the value of DPPC estimation in the clinical management of children with asthma remains to be determined.

A single nucleotide polymorphism in the CCR3 gene ablates receptor export to the plasma membrane

BACKGROUND

The chemokine receptor CCR3 orchestrates the migration of eosinophils, basophils, T(H)2 lymphocytes, and mast cells during the allergic response, with CCR3 blockade a potential means of therapeutic intervention. Non-synonymous single nucleotide polymorphisms (SNPs) within the ccr3 gene have previously been described, with little information regarding their effects on CCR3 function.

OBJECTIVE

To characterize the effects of nonsynonymous SNPs within the ccr3 gene.

METHODS

Site-directed mutagenesis was used to generate N-terminally tagged mutant CCR3 constructs corresponding to reported SNPs. Cell transfectants expressing either wild-type or mutant CCR3 were studied by flow cytometry, Western blotting, and confocal microscopy and examined for their ability to migrate to the CC chemokine ligand CCL11/eotaxin.

RESULTS

An L324P mutant CCR3 protein corresponding to the previously identified T971C SNP was not expressed at the cell surface, and cells remained unresponsive to CCL11 in chemotaxis assays. Confocal microscopy confirmed that L324P-CCR3 had a predominantly intracellular distribution compared with wild-type CCR3. A L324A variant of CCR3 had an identical phenotype to the L324P mutant, suggesting that L324 per se is critical for successful trafficking of nascent CCR3 to the cell membrane. The processes involved appear to be specific for CCR3, because an identical mutation in the homologous receptor CCR1 had minor effects.

CONCLUSION

Trafficking to the cell surface of nascent CCR3 is critically dependent on a C-terminal leucine residue, suggestive of specific mechanisms for CCR3 export. Manipulation of these mechanisms may suggest novel means of antagonizing CCR3 function in the treatment of allergy.

The roles of a Th2 cytokine and CC chemokine in children with stable asthma: potential implication in eosinophil degranulation

Th2 cytokine IL-5 and CC chemokine eotaxin are thought to be key regulators of eosinophils in bronchial asthma. However, their involvement in children with stable asthma (SA) has not been determined. We investigated the roles of IL-5 and eotaxin in eosinophil degranulation in children with SA. Induced sputum was obtained from 30 SA, 21 allergic rhinitis (AR), and 22 non-atopic healthy control (HC) children. We measured sputum levels of IL-5, eotaxin, and eosinophil indices [percentage eosinophils, eosinophil-derived neurotoxin (EDN), and eosinophil-cationic protein (ECP)]. We also examined correlations of IL-5 and eotaxin with eosinophil indices. Sputum percentage eosinophils and EDN and ECP levels were significantly higher in the SA group than in the HC group, while only the sputum EDN and ECP levels were significantly higher in the AR group than in the HC group. Unexpectedly, sputum levels of IL-5 were not significantly different among the three groups; however, the levels of eotaxin were higher in the SA group when compared to the HC group. No significant correlations were found between IL-5 and percentage eosinophils, EDN, or ECP levels; in contrast, eotaxin levels correlated significantly with percentage eosinophils (R(s) = 0.638; p = 0.0001), EDN (R(s) = 0.522; p = 0.003), and ECP levels (R(s) = 0.630 and p = 0.0002). The elevated levels and good correlations of eotaxin with sputum eosinophil indices, and no elevation or correlation of IL-5 with these indices, suggest that CC chemokine eotaxin may play a more important role in eosinophil degranulation in children with SA.

Bronchial epithelial cells produce IL-5: implications for local immune responses in the airways

IL-5 is a pleiotropic cytokine that promotes eosinophil differentiation and survival. While naïve bronchial epithelial cells (BEC) produce low levels of IL-5, the role of BEC-derived IL-5 in allergic airway inflammation is unknown. We now show that BEC, isolated from mice with OVA-induced allergic airway disease (AAD), produced elevated levels of IL-5 mRNA and protein as compared to BEC from naïve mice. To determine the contribution of BEC-derived IL-5 to effector responses in the airways, IL-5 deficient bone marrow chimeric mice were generated in which IL-5 expression was restricted to stromal (e.g. BEC) or hematopoietic cells. When subjected to AAD, IL-5 produced by BECs contributed to mucous metaplasia, airway eosinophilia, and OVA-specific IgA levels. Thus, IL-5 production by BEC can impact the microenvironment of the lung, modifying pathologic and protective immune responses in the airways.

A novel CC-chemokine receptor 3 antagonist, Ki19003, inhibits airway eosinophilia and subepithelial/peribronchial fibrosis induced by repeated antigen challenge in mice

CC-chemokine receptor 3 (CCR3) is a chemokine receptor for which major ligands, CC-chemokine ligand (CCL) 11, CCL24, and CCL26, are known to be involved in chemotaxis for eosinophils. In the present study, we evaluated the effect of a low molecular weight CCR3-receptor antagonist, Ki19003 (4-[[5-(2,4-dichlorobenzylureido)pentyl][1-(4-chlorophenyl)ethyl]amino]butanoic acid), on airway remodeling in a mouse model of allergic asthma. BALB/c mice were sensitized twice by intraperitoneal injection of ovalbumin (OA) and exposed daily to 1% OA for 3 weeks. Twenty-four hours after the final antigen challenge, bronchoalveolar lavage and histological examinations were carried out. Ki19003 clearly inhibited antigen-induced increase in the number of eosinophils in bronchoalveolar lavage fluid (BALF), but did not affect the number of other cell types examined in this study. Ki19003 also inhibited the increased production of transforming growth factor-beta1 in BALF and the amount of hydroxyproline in the lungs in a dose-dependent manner. Furthermore, Ki19003 significantly attenuated allergen-induced subepithelial and peribronchial fibrosis. These findings indicate that CCR3 antagonism prevents not only the infiltration of eosinophils into the airways but also the development of allergen-induced subepithelial and peribronchial fibrosis. Therefore, a CCR3 antagonist may be useful in the treatment of airway remodeling, especially subepithelial and peribronchial fibrosis, in allergic asthma.

Ontogeny of the eotaxins in human lung

The ontogeny of the C-C chemokines eotaxin-1, eotaxin-2, and eotaxin-3 has not been fully elucidated in human lung. We explored a possible role for eotaxin in developing lung by determining the ontogeny of eotaxin-1 (CCL11), eotaxin-2 (CCL24), eotaxin-3 (CCL26), and the eotaxin receptor, CCR3. We tested discarded surgical samples of developing human lung tissue using quantitative RT-PCR (QRT-PCR) and immunostaining for expression of CCL11, CCL24, CCL26, and CCR3. We assessed possible functionality of the eotaxin-CCR3 system by treating lung explant cultures with exogenous CCL11 and analyzing the cultures for evidence of changes in proliferation and activation of ERK1/2, a signaling pathway associated with CCR3. QRT-PCR analyses of 22 developing lung tissue samples with gestational ages 10-23 wk demonstrated that eotaxin-1 mRNA is most abundant in developing lung, whereas mRNAs for eotaxin-2 and eotaxin-3 are minimally detectable. CCL11 mRNA levels correlated with gestational age (P < 0.05), and immunoreactivity was localized predominantly to airway epithelial cells. QRT-PCR analysis detected CCR3 expression in 16 of 19 developing lung samples. Supporting functional capacity in the immature lung, CCL11 treatment of lung explant cultures resulted in significantly increased (P < 0.05) cell proliferation and activation of the ERK signaling pathway, which is downstream from CCR3, suggesting that proliferation was due to activation of CCR3 receptors by CCL11. We conclude that developing lung expresses the eotaxins and functional CCR3 receptor. CCL11 may promote airway epithelial proliferation in the developing lung.

The polymorphisms of Eotaxin 1 and CCR3 genes influence on serum IgE, Eotaxin levels and mild asthmatic children in Taiwan

BACKGROUND

Asthma is a complex disorder, which is known to be affected by interactions between genetic and environmental factors. The human Eotaxin 1 and CCR3 attract eosinophils and Th2-lymphocytes to migrate to the inflammatory foci that could represent a key mechanism in allergy and asthma.

OBJECTIVE

We hypothesized that Eotaxin1 gene Ala23Thr and A-384 G, and CCR3 gene T51C polymorphisms are associated with plasma Eotaxin levels and predispose individuals to asthma pathogenesis.

METHODS

One hundred seventy-eight hospital-based asthmatic children and 277 community-based controls aged from 5 to 12 years were recruited in southern Taiwan. Whole blood samples and questionnaires were collected. In this study, we addressed genetic effects of Eotaxin 1 and CCR3 genes on asthma, plasma IgE and Eotaxin 1 levels.

RESULTS

In comparison with subjects with Ala23Ala genotype, Ala23Thr polymorphism of the Eotaxin 1 gene showed a significant protective effect on asthma (AOR = 0.58, 95% CI = 0.37-0.92). We demonstrated that the mean Eotaxin 1 concentration was significantly higher in subjects with Ala23Ala than in subjects with Thr23Thr (P = 0.005) or Ala23Thr (P = 0.07), which showed a gene-dose dependent relationship. But, we observed that the A-384G polymorphism of Eotaxin 1 gene and T51C polymorphism of CCR3 gene are not associated with asthma.

CONCLUSION

This study finding provide a strong evidence that Eotaxin 1 Thr23Thr homozygote has a protective effect on asthma and significantly decreases plasma Eotaxin 1 concentrations in asthmatics in Taiwan.

Expression of interleukin-17F in a mouse model of allergic asthma

BACKGROUND

Interleukin (IL)-17F is a recently discovered cytokine and is derived from a panel of limited cell types, such as activated CD4+ T cells, basophils, and mast cells. IL-17F is known to induce several cytokines and chemokines. However, its involvement in airway inflammation has not been well understood. To this end, the expression of IL-17F and the inhibitory effects of glucocorticoids on its expression in a mouse model of asthma were examined.

METHODS

Five-week-old BALB/c male mice were sensitized by intraperitoneal injection (i.p.) of ovalbumin (OVA) with alum, and challenged by daily inhalation of aerosolized 1% OVA. 24 h after last challenge (OVA/OVA), the expression of IL-17F was examined in lung tissues by immunohistochemistry and reverse-transcription polymerase chain reaction. Control mice were sensitized and challenged with saline (Sham/Sham). In addition, a group OF OVA-sensitized mice received i.p. injection of water-soluble dexamethasone (DEX) in saline 1 h before ova challenge (OVA/DEX).

RESULTS

In sham-challenged mice, IL-17F was not expressed in the lungs, while, in contrast, IL-17F was predominantly expressed in bronchial epithelial cells in addition to the infiltrating inflammatory cells in OVA/OVA mice. Further, the expression of IL-17 F was significantly attenuated by the treatment of mice with DEX.

CONCLUSION

These results suggest that bronchial epithelium-derived IL-17F may represent a new pharmacological target for glucocorticoids and may play a role in allergic asthma.

Apoptotic eosinophils in sputum from asthmatic patients correlate negatively with levels of IL-5 and eotaxin

BACKGROUND

Eosinophilic inflammation of the airways is a key characteristic of asthma. A defect in eosinophil apoptosis might contribute to the chronic tissue eosinophilia associated with asthma.

OBJECTIVE

Our purpose was to examine whether the occurrence of apoptotic eosinophils in induced sputum from asthmatic patients correlate with interleukin (IL)-5 and eotaxin.

METHODS

Thirty stable and 30 exacerbated asthmatic patients were recruited. Twenty healthy subjects were enrolled as a control group. Induced sputum was obtained from asthmatic patients and from control subjects. The number of apoptotic eosinophils in sputum was assessed by flow cytometry. In sputum supernatant, eosinophil cationic protein (ECP) was measured by sensitive radioimmunoassay, and IL-5 and eotaxin by sandwich enzyme linked immunosorbant assay.

RESULTS

Levels of eosinophils, apoptotic eosinophils, IL-5, ECP and eotaxin from asthmatic patients were higher than those from healthy subjects. Thirty exacerbated asthmatics showed higher proportions of eosinophils (median 29.3%, range 13.4%-40.9%), more detectable levels of IL-5 (50.44, 32.99-67.01 pg/ml) and eotaxin (644.6, 197.4-937.7 pg/ml) in their sputum than the patients with stable asthma (P<0.05). There were significant inverse correlations between the levels of sputum IL-5 and the proportion of sputum eosinophil apoptosis in patients with exacerbated and stable asthma (r=-0.85 and -0.79, P<0.01 and P<0.05, respectively). Also inverse correlations were found between the levels of eotaxin and the proportion of sputum eosinophil apoptosis in exacerbated (r=-0.85, P<0.01), or stable asthma (r=-0.69, P<0.05). Additional positive correlations between the levels of sputum IL-5 and eotaxin in either exacerbatated (r=0.93, P<0.01) or stable asthma (r=0.82, P<0.05) were observed.

CONCLUSIONS

Apoptosis of eosinophils might be suppressed by proinflammatory cytokines and chemokines such as IL-5 and eotaxin leading to their accumulation in the lung. Stimulation of eosinophils in airway with IL-5 and eotaxin may play a crucial role in allergic inflammation.

Factors contributing to nasal allergic late phase eosinophilia

OBJECTIVE

This study focused on factors contributing to eosinophilia after intranasal allergen challenge.

METHODS

Nasal secretions of 13 allergic individuals were gained over a period of 8 hours after nasal allergen challenge. Early and late phase reactions were determined by acoustic rhinometry and changes of volume and total protein in nasal secretions. Eosinophilia was demonstrated by nasal eosinophilic cationic protein. Interleukin (IL)-5; the chemokines IL-8, monocyte chemotactic protein (MCP)-1 and MCP-3, and eotaxin; soluble vascular cell adhesion molecule 1 (sVCAM-1); and the leukotriene C4 (LTC4) were analyzed by enzyme-linked immunosorbent assay for their suggested impacts on tissue eosinophilia.

RESULTS

By means of rhinometry, we observed in 69% an alternating type of late phase response, followed by a bilateral (15%) or unilateral (8%) type. A biphasic kinetic could be demonstrated by changes in nasal volume and total protein of nasal secretions, reflecting the early and late phase responses. A typical late phase kinetic was observed for IL-5, MCP-1, eotaxin, sVCAM-1, and LTC4. Interleukin 8 was characteristic for early phase reaction but increased in late phase as well. We could not detect any MCP-3 in our samples.

CONCLUSIONS

Our data point to a relevant role of the T(H)2 cytokine IL-5; of the chemokines IL-8, MCP-1, and eotaxin; of the adhesion molecule sVCAM-1; and of the leukotriene LTC4 for the allergic late phase eosinophilia.

Eotaxin polymorphisms and serum total IgE levels in children with asthma

BACKGROUND

Eotaxin (chemokine, CC motif, ligand; CCL11) is a potent eosinophil chemoattractant strongly implicated in the pathobiology of asthma. Genetic variation at the CCL11 locus has been correlated with serum total IgE, blood eosinophil counts, and circulating eotaxin protein levels in several case-control asthma studies. Family-based association studies of CCL11 genetic variants have not been reported to date.

OBJECTIVE

To evaluate 9 common CCL11 single nucleotide polymorphisms (SNPs) in nuclear families ascertained through patients with asthma participating in the Childhood Asthma Management Program study.

METHODS

Single nucleotide polymorphism genotyping was performed by using minisequencing and probe hybridization platforms. Family-based association analysis for asthma and 4 asthma-related intermediate quantitative phenotypes was performed by using FBAT.

RESULTS

One SNP, -384A>G, was associated with asthma among African American families (P = .01). CCL11 SNPs and haplotypes were not associated with asthma among white or Hispanic families. Two low-frequency alleles in strong pairwise linkage disequilibrium, -426C and IVS2+199A, were associated with lower serum total IgE levels (P = .0006 and P = .009, respectively) in white families, whereas 2 more common variants, -576C and g.4438C, were associated with higher IgE levels in African American families (P = .01-.04). Haplotype analysis in the white cohort provided additional evidence of association with serum total IgE, implicating 2 haplotypes. No single SNP or haplotype associations were observed with blood eosinophil levels, FEV(1), or airway responsiveness.

CONCLUSION

These findings provide further evidence that genetic variation at the CCL11 locus is an important determinant of serum total IgE levels among patients with asthma.

Neuronal eotaxin and the effects of CCR3 antagonist on airway hyperreactivity and M2 receptor dysfunction

Eosinophils cluster around airway nerves in patients with fatal asthma and in antigen-challenged animals. Activated eosinophils release major basic protein, which blocks inhibitory M2 muscarinic receptors (M2Rs) on nerves, increasing acetylcholine release and potentiating vagally mediated bronchoconstriction. We tested whether GW701897B, an antagonist of CCR3 (the receptor for eotaxin as well as a group of eosinophil active chemokines), affected vagal reactivity and M2R function in ovalbumin-challenged guinea pigs. Sensitized animals were treated with the CCR3 antagonist before inhaling ovalbumin. Antigen-challenged animals were hyperresponsive to vagal stimulation, but those that received the CCR3 antagonist were not. M2R function was lost in antigen-challenged animals, but not in those that received the CCR3 antagonist. Although the CCR3 antagonist did not decrease the number of eosinophils in lung tissues as assessed histologically, CCR3 antagonist prevented antigen-induced clustering of eosinophils along the nerves. Immunostaining revealed eotaxin in airway nerves and in cultured airway parasympathetic neurons from both guinea pigs and humans. Both IL-4 and IL-13 increased expression of eotaxin in cultured airway parasympathetic neurons as well as in human neuroblastoma cells. Thus, signaling via CCR3 mediates eosinophil recruitment to airway nerves and may be a prerequisite to blockade of inhibitory M2Rs by eosinophil major basic protein.

IgE- and FcepsilonRI-mediated migration of human basophils

Local accumulation of basophils at inflammatory sites is observed in experimental antigen challenge and in allergic diseases. It is not fully known what factor(s) regulates local basophil influx in tissues, and it has not been determined whether antigens belong in a panel of basophil chemoattractants. This study was designed to elucidate whether IgE- and high-affinity receptor for IgE (FcepsilonRI)-mediated stimulation can induce human basophil migration. The migration-inducing potency of an anti-FcepsilonRI alpha-chain mAb, CRA-1, was examined on human basophils. CRA-1 mAb elicited significant migration of basophils. The migration-inducing potency of this mAb was maximal at 100 ng ml-1, and CRA-1 mAb at 100 ng ml-1 attracted approximately 10% of total inoculated basophils above baseline levels after incubation for 2.5 h. Checkerboard analysis indicated that basophil migration induced by this mAb was mainly chemotactic and partially chemokinetic. An antigen, Der f 2, also induced migration of basophils from Der f-sensitive subjects. Basophils mixed with 1 ng ml-1 of CRA-1 mAb showed an exaggerated migration response to eotaxin, indicating that FcepsilonRI cross-linkage enhances basophil migration to other chemoattractants. Induction of basophil migration by IgE- and FcepsilonRI-cross-linking stimulation may, at least in part, explain the pathogenesis of local basophil accumulation clinically observed in allergic diseases such as asthma.

Effects of corticosteroid on the expression of thymus and activation-regulated chemokine in a murine model of allergic asthma

BACKGROUND

Thymus and activation-regulated chemokine (TARC; CCL17) is a lymphocyte-directed CC chemokine that specifically attracts T-helper (Th) 2 cells positive for the CC chemokine receptor 4 (CCR4(+)). Corticosteroids reduce airway inflammation, as reflected by reduced numbers of eosinophils and T cells and reduced expression of cytokines. We investigated TARC production and the inhibitory effects of corticosteroids on TARC expression in a murine model of allergic asthma.

METHODS

BALB/c mice were sensitized by intraperitoneal injection of ovalbumin (OVA) with alum. Once daily for 1 week, mice received injections of dexamethasone or 0.2 ml saline (control), then 1 h later inhaled aerosolized 1% OVA for 30 min. Mice were killed 24 h after OVA challenge for bronchoalveolar lavage and lung tissue examination.

RESULTS

TARC was expressed mainly in the bronchial epithelial cells. Dexamethasone attenuated OVA-induced airway eosinophilia, lymphocyte infiltration, and airway hyperresponsiveness. Dexamethasone also decreased TARC production in the bronchoalveolar lavage fluid and decreased expression of TARC mRNA and TARC protein in lung tissue.

CONCLUSIONS

The corticosteroid dexamethasone inhibits TARC production in a murine model of allergic asthma in vivo. The beneficial effect of corticosteroids in bronchial asthma is due in part to their direct inhibitory effects on TARC production.

Assessment of signal transducer and activator of transcription 6 as a target of glucocorticoid action in human airway epithelial cells

BACKGROUND

Activation of signal transducer and activator of transcription (STAT)6 by IL-4 and IL-13 is essential in many key epithelial responses in the asthmatic airway including expression of numerous chemokines, goblet cell differentiation and mucus production and expression of other allergic inflammatory genes. While these responses are all inhibited by glucocorticoids (GC) administered systemically or by inhalation, the inhibitory mechanisms are unknown.

OBJECTIVE

To test the hypothesis that GC suppress allergic responses by blocking IL-4-induced STAT6 signalling in airway epithelial cells.

METHODS

Western blotting and reporter gene assays were used to determine whether GC could inhibit STAT6 production, phosphorylation or nuclear translocation, or whether GC could affect STAT6 transcriptional activity in the BEAS-2B airway epithelial cell line.

RESULTS

Our results showed that GC had no inhibitory effect on the total cellular or nuclear levels of STAT6 or phospho-STAT6. GC did not inhibit transcription from three different STAT6-driven reporter constructs, indicating that GC also did not inhibit STAT6 function.

CONCLUSION

We conclude that airway epithelial STAT6 is not the central target of GC in allergic inflammation and that the inhibitory effect of GC on STAT6-mediated IL-4- and IL-13-induced responses is exerted by targeting pathways distinct from STAT6.

Effect of influenza vaccinations on immune response and serum eotaxin level in patients with allergic bronchial asthma

BACKGROUND

One of the most promising markers of allergic inflammation is eotaxin, which has a selective influence on the migration of eosinophils. Its serum content significantly correlates with the intensity of allergic symptoms, so it might be interesting to know whether vaccination has any influence on serum expression of this chemokine.

AIMS

Comparison of the humoral response to influenza vaccine and post-vaccination changes in the serum eotaxin level in patients with allergic bronchial asthma and healthy controls.

METHODS

Forty-two asthmatics and 45 healthy individuals were vaccinated with a single dose of influenza subunit vaccine (Influvac). The serum eotaxin level and the antibody response to haemagglutinin (HI) and neuraminidase (NI) glycoproteins were measured before and after vaccination.

RESULTS

A significant increase of geometric mean titres of HI and NI was observed in both groups. There were no significant differences between the groups in meanfold increase of HI and NI titres, response rate and protective level of HI. After vaccination, a significant decrease of the mean serum eotaxin value was observed in patients with asthma (149.4 +/- 71.0 versus 125.1 +/- 67.0, p= 0.0017), while no similar effect was present in healthy individuals (153.4 +/- 56.9 versus 159.3 +/- 54.4, p= 0.5).

CONCLUSIONS

The results indicate that in patients with allergic bronchial asthma influenza vaccinations assure efficient protective antibody level and modulate the serum level of eotaxin.

Increased macrophage-derived chemokine in exhaled breath condensate and plasma from children with asthma

BACKGROUND

Type 2 helper T lymphocyte-specific chemokines including macrophage-derived chemokine (MDC), thymus and activation-regulated chemokine (TARC) and eotaxin are important mediators for allergic airway inflammation.

OBJECTIVE

We investigated whether these chemokines can be detected in exhaled breath condensate (EBC) and their relation to childhood asthma.

METHODS

Asthmatics recruited from paediatric clinics of a university teaching hospital were classified into intermittent asthma (IA) and persistent asthma (PA) according to Global Initiative for Asthma guidelines. EBC was collected by a disposable collection kit, whereas fractional exhaled nitric oxide (FENO) was measured by a chemiluminescence analyser. Concentrations of MDC, TARC and eotaxin in both EBC and plasma were measured using sandwich enzyme immunoassay. The intra-subject reproducibility of exhaled chemokine measurements was determined by co-efficients of variation (CV).

RESULTS

Forty-eight patients with PA, 36 children with IA and 18 controls were recruited. MDC and eotaxin were present in EBC from nearly all subjects, whereas TARC could be measured in EBC from 33 (32%) subjects only. The median MDC concentration in EBC was higher in PA (117 pg/mL) as compared with IA (106 pg/mL) and controls (105 pg/mL; P=0.003 for both). The median plasma MDC concentration in PA (648 pg/mL) was also higher than that in IA (520 pg/mL; P=0.002) and controls (490 pg/mL; P=0.008). The median plasma TARC concentration was also increased in PA as compared with IA (72 pg/mL vs. 35 pg/mL; P=0.004). MDC concentrations in EBC were lower in patients with PA who received high-dose inhaled corticosteroid (P=0.005). FENO was significantly higher in asthmatics than controls (P<0.0001), but it was not associated with chemokines in EBC or plasma. The mean (range) CV for measuring MDC, TARC and eotaxin in EBC (n=6) were 5.5 (2.0-7.2%), 8.8 (3.6-14.4%) and 5.2 (2.8-7.9%), respectively.

CONCLUSIONS

Our results suggest that MDC in EBC and MDC and TARC in plasma are increased in children with PA as compared with IA or control. MDC concentrations in EBC are suppressed in patients on high-dose inhaled corticosteroid treatment.

Contribution of eotaxin-1 to eosinophil chemotactic activity of moderate and severe asthmatic sputum

The CC chemokine eotaxin-1 (CCL11) is chemotactic for eosinophils, basophils, and type 2 helper T cells and may play a role in allergic inflammation. We investigated its contribution as an eosinophil chemoattractant in asthmatic airway secretions (sampled as induced sputum), which possess chemotactic activity for eosinophils and T cells. Sputum samples collected from healthy subjects and subjects with mild, stable-moderate, unstable-moderate, and severe asthma were processed with phosphate-buffered saline and assayed for eotaxin by ELISA and for eosinophil chemotactic activity by fluorescence-based chemotaxis assay. The contribution of eotaxin to chemotactic activity was studied by using a high-affinity neutralizing human anti-eotaxin antibody, CAT-213. Sputum eotaxin concentration was significantly raised in moderate and severe asthma (p < 0.05 versus healthy control subjects) but not in mild asthma. Chemotactic activity was significantly increased in all asthmatic groups relative to healthy subjects (p < 0.05) and was significantly inhibited by CAT-213 (100 nM) in subjects with moderate and severe asthma, with median inhibition of 52% (p < 0.05), 78% (p < 0.0001), and 86% (p < 0.0001), respectively, in samples representing stable-moderate, unstable-moderate, and severe asthma. Eotaxin contributed to the eosinophil chemotactic activity of sputum from subjects with more severe forms of asthma but not mild asthma, suggesting that its contribution is more important in more severe disease. This activity is inhibited significantly by CAT-213.

Airway Inflammation after Cessation of Exposure to Agents Causing Occupational Asthma

Subjects with occupational asthma (OA) generally present asthma symptoms and airway hyperresponsiveness after cessation of exposure. We hypothesized that they are also left with airway inflammation. We assessed 133 subjects with OA at a mean interval of 8.7 years (0.5-20.8 years) after cessation of exposure by questionnaire, airway caliber, and responsiveness to methacholine. Satisfactory samples of induced sputum were obtained from 98 subjects. We defined three groups of subjects: (1) cured: normalization of the concentration of methacholine provoking a 20% decrease in FEV1 (PC20), (2) improved: increase in PC20 by 3.2-fold or more but PC20 still abnormal, and (3) not improved: no significant change in PC20. In all, 9/28 subjects (32.1%) with no improvement versus 6/56 (10.7%) subjects with partial and complete improvements had sputum eosinophils equal to or greater than 2% and 11/28 (39.3%) subjects versus 11/56 (19.6%) subjects showed sputum neutrophils equal to or greater than 61%. Levels of interleukin-8 and of the neutrophil-derived myeloperoxidase were significantly more elevated in sputum of subjects with no improvement. Those in the cured or improved groups had a significantly longer time lapse since diagnosis and a higher PC20 at the time of diagnosis. We conclude that failure to improve after cessation of exposure to an agent causing OA is associated with airway inflammation at follow-up.

Cc-chemokine eotaxin as a marker of efficacy of specific immunotherapy in patients with intermittent IgE-mediated allergic rhinoconjunctivitis

BACKGROUND

Allergen-specific immunotherapy (SIT) is believed to be a valuable remedy in several allergic diseases; however, an accurate immunological marker of the efficacy of this treatment method has not been found yet. Cc-chemokine eotaxin, owing to its selective action on eosinophils, seems to play an important role in the pathophysiology of allergic response. The purpose of this study was to assess the usefulness of eotaxin in monitoring of SIT efficacy in patients with IgE-mediated allergic rhinoconjunctivitis.

METHODS

One hundred and twenty-two patients with seasonal IgE-mediated allergic rhinoconjunctivitis due to tree- (birch, n = 42; hazel/alder, n = 14) or grass/cereal- (n = 66) pollen received allergen-specific immunotherapy. Serum eotaxin levels were determined four times in every patient, shortly before immunotherapy (Evaluation 0), immediately after the treatment (Evaluation 1), in the height of pollen season (Evaluation 2) and at least 2 weeks after the pollen season (Evaluation 3). Serum eotaxin levels were simultaneously measured in 59 healthy people from the control group. Changes in serum eotaxin levels were assessed in the healthy and allergic groups. Clinical symptoms of IgE-mediated rhinoconjunctivitis were evaluated and compared with serum eotaxin concentration changes.

RESULTS

Mean values of eotaxin concentrations in serum during Evaluations 0-3 did not significantly differ in the healthy subjects and the patients with IgE-mediated rhinoconjunctivitis (P > 0.05). Moreover, no statistically significant differences in the serum eotaxin levels between the visits were observed in the patients who received immunotherapy (P > 0.05); however, immediately after immunotherapy (Evaluation 1) the mean serum level of eotaxin was lowest and closest to the serum eotaxin concentration in the control group at the same visit. No significant correlation between the mean value of the serum eotaxin level in the height of pollen season (r = -0.12, P > 0.05) or mean changes of the eotaxin levels between Evaluations 2 and 1 (r = -0.03, P > 0.05), on the one hand, and the cumulative score of symptoms and drug, on the other, were found.

CONCLUSIONS

The results allow to conclude that although eotaxin plays a significant role in the mechanism of antigen-specific immunotherapy, its serum expression remains a poor marker of SIT efficacy.

Eotaxin protein levels and airway pathology in a mouse model for allergic asthma

Eotaxin is a chemokine implicated in eosinophil trafficking and may be involved in the development of airway hyperresponsiveness. The role of eotaxin in a mouse model for allergic asthma was investigated. Challenging ovalbumin-sensitised mice with ovalbumin aerosol leads to airway hyperresponsiveness and airway eosinophilia 24 h after the last challenge. Furthermore, eotaxin concentrations were markedly increased in lungs and broncho-alveolar lavage fluid of ovalbumin-challenged mice compared to vehicle treated mice. This could mean that eotaxin is implicated in the pathology of this model. To further investigate the role of eotaxin in this murine model for allergic asthma, the ovalbumin response was modulated by either treatment with eotaxin antibodies or additional eotaxin, to suppress or promote the development of airway hyperresponsiveness and inflammation. Administration of eotaxin antibodies or an additional intravenous eotaxin injection did not alter the development of ovalbumin-induced airway hyperresponsiveness and eosinophilia. In conclusion, eotaxin concentrations were increased in a murine model for allergic airway inflammation. However, anti-eotaxin antibodies or additive intravenous murine eotaxin did not influence airway inflammation and hyperresponsiveness in this mouse model for allergic asthma.

Eotaxin/CCL11 is involved in acute, but not chronic, allergic airway responses to Aspergillus fumigatus

Eotaxin/CCL11 is a major chemoattractant for eosinophils and Th2 cells. As such, it represents an attractive target in the treatment of allergic disease. The present study addresses the role of eotaxin/CCL11 during acute and chronic allergic airway responses to the fungus Aspergillus fumigatus. Mice lacking the eotaxin gene (Eo-/-) and wild-type mice (Eo+/+) were sensitized to A. fumigatus and received either an intratracheal challenge with soluble A. fumigatus antigens (acute model) or an intratracheal challenge with live A. fumigatus spores or conidia (chronic model). Airway hyperresponsiveness and eosinophil, but not T cell, recruitment were significantly decreased at 24 h after the soluble allergen in A. fumigatus-sensitized Eo-/- mice compared with similarly sensitized Eo+/+ mice. In contrast, the development of chronic allergic airway disease due to A. fumigatus conidia was not altered by the lack of eotaxin. Together, these data suggest that eotaxin initiates allergic airway disease due to A. fumigatus, but this chemokine did not appear to contribute to the maintenance of A. fumigatus-induced allergic airway disease.

Increased plasma eotaxin in atopic dermatitis and acute urticaria in infants and children

BACKGROUND

The previously reported eotaxin overexpression in the lesional skin of atopic dermatitis (AD) led us to the assumption that circulating levels of eotaxin may be elevated too. We sought to investigate the plasma expression of eotaxin in children with skin allergy in relation to clinical activity and type of lesions.

METHODS

Plasma eotaxin was assayed in 78 infants and children, of whom 16 had AD, 19 had acute urticaria (AU), and 43 were healthy matched subjects. Seven children in the group of AU were resampled for plasma eotaxin after clinical remission.

RESULTS

The plasma eotaxin levels in AD (median=158 pg/ml, mean [SD]=168 [61] pg/ml) were significantly higher than the control values (median=60 pg/ml, mean [SD]=59.5 [18.5] pg/ml). Not only did patients with AU demonstrate elevated plasma eotaxin levels (median=126 pg/ml, mean [SD]=124 [33] pg/ml), but also a significant decline occurred on follow-up. The coexistence of angioedema with AU did not cause any further increase in plasma eotaxin expression. Plasma eotaxin levels were significantly higher in AD than in AU, probably reflecting the chronic nature of eczematous AD lesions. The plasma eotaxin levels did not correlate with serum total IgE, peripheral blood absolute eosinophil count, or age of the patients. However, there was a positive correlation between age and plasma eotaxin in the control group.

CONCLUSION

Our findings imply that circulating levels of eotaxin increase in AD and during flares of AU, probably to serve in the recruitment and activation of eosinophils. It may also represent a biomarker of lesional activity.

The kinetics of allergen-induced eotaxin level in nasal lavage fluid: its key role in eosinophil recruitment in nasal mucosa

Eotaxin (CCL11) is a potent eosinophil chemoattractant belonging to the C-C chemokine. To evaluate the role of eotaxin in eosinophilic inflammation in nasal mucosa, we investigated the levels of eosinophil chemoattractants in nasal lavage fluids obtained after antigen challenge, compared with eosinophil counts and eosinophil protein X (EPX) levels. In subjects with allergic rhinitis, allergen challenge led to parallel increases in eosinophil counts, levels of EPX, and eotaxin concentrations in nasal lavage fluid. The levels of eotaxin in lavage samples showed strong correlation with lavage levels of eosinophil counts and EPX. Normal subjects had few, if any, eosinophils and EPX as well as the measured parameters in their nasal lavage fluids before and after antigen challenge. In our experiments of eosinophil endothelial transmigration (TEM) assay using the nasal microvascular endothelial cells, eotaxin showed the most potent effect among various eosinophil chemoattractants. In addition, treatment of eosinophils with anti-CCR-3 mAb significantly blocked eosinophil TEM induced by homogenate of nasal mucosa. These results indicate that eotaxin has an important role in eosinophil-dependent inflammation in nasal mucosa and suggest that blocking eotaxin or CCR-3 might be useful for new therapeutic tools of allergic rhinitis.

Chemokines and their role in airway hyper-reactivity

Airway hyper-reactivity is a characteristic feature of many inflammatory lung diseases and is defined as an exaggerated degree of airway narrowing. Chemokines and their receptors are involved in several pathological processes that are believed to contribute to airway hyper-responsiveness, including recruitment and activation of inflammatory cells, collagen deposition and airway wall remodeling. These proteins are therefore thought to represent important therapeutic targets in the treatment of airway hyper-responsiveness. This review highlights the processes thought to be involved in airway hyper-responsiveness in allergic asthma, and the role of chemokines in these processes. Overall, the application of chemokines to the prevention or treatment of airway hyper-reactivity has tremendous potential.