Increased expression of the chemoattractant cytokines eotaxin, monocyte chemotactic protein-4, and interleukin-16 in induced sputum in asthmatic patients

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.

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.

Pediatric asthma: guidelines-based care, omalizumab, and other potential biologic agents

Over the past several decades, the evidence supporting rational pediatric asthma management has grown considerably. As more is learned about the various phenotypes of asthma, the complexity of management will continue to grow. This article focuses on the evidence supporting the current guidelines-based pediatric asthma management and explores the future of asthma management with respect to phenotypic heterogeneity and biologics.

Astragalus membranaceus modulates Th1/2 immune balance and activates PPARγ in a murine asthma model

Astragalus membranaceus, a traditional Chinese herb, has been used to improve airway inflammation and asthma. The present study investigated whether A. membranaceus has immunotherapeutic effects on asthma, a chronic inflammatory mucosal disease that is associated with excess production of IgE, eosinophilia, T helper 2 (Th2) cytokines, and bronchial hyperresponsiveness. An ovalbumin (OVA)-induced, chronic inflammatory airway murine asthma model was used to examine the status of pulmonary inflammation after the administration of A. membranaceus. The IgE levels in serum and bronchoalveolar lavage fluid showed a tendency to decrease after the administration of A. membranaceus. The number of eosinophils decreased and infiltration of inflammatory cells and collagen deposition declined in lung sections after A. membranaceus administration. The RNA and protein levels of Th2 cytokines and the ratio of the GATA3/T-bet mRNA levels decreased after A. membranaceus treatment. Furthermore, the mRNA level of peroxisome proliferator-activated receptor γ (PPARγ), a nuclear hormone receptor, increased in the lung tissues of A. membranaceus-treated mice. Finally, an A. membranaceus water extract activated PPARγ activity in either human embryonic kidney 293 (HEK293) or A549 cells in a PPARγ-responsive element-containing luciferase reporter assay. These results indicate that A. membranaceus has an inhibitory effect on airway inflammation in a murine model of asthma through modulating the imbalanced relationship between Th1 and Th2 cytokines.

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.

Monoclonal antibodies for asthma and chronic obstructive pulmonary disease

INTRODUCTION

In asthma and chronic obstructive pulmonary disease (COPD), the inflammation in the airways cannot always be controlled with conventional therapies, such as inhaled corticosteroids. Addition of more specific anti-inflammatory therapies, such as monoclonal antibodies, against inflammation pathways might improve the disease outcome.

AREAS COVERED

This review individually discusses the major inflammation pathways and their potential blocking monoclonal antibodies in asthma and COPD.

EXPERT OPINION

The current use of omalizumab in asthma provides a good example on the potential therapeutic role of monoclonal antibodies in both asthma and COPD. There are many other monoclonal antibodies which are currently investigated as possible therapies in these diseases. The identification of the disease subsets in which such antibodies might exert the maximum benefit opens the door for personalized medicine and for targeted biological therapy in asthma and COPD.

Neutrophil and eosinophil granulocytes as key players in a mouse model of chemical-induced asthma

Diisocyanates are an important cause of chemical-induced occupational asthma. This type of immunologically mediated asthma is often characterized by a predominant granulocytic inflammation in the airways, rather than an infiltration by lymphocytes. We sought to determine the contribution of granulocytes in the outcome of chemical-induced asthma using general and specific leukocyte depletion strategies in an established mouse model of isocyanate asthma. On days 1 and 8, BALB/c mice received dermal applications with toluene-2,4-diisocyanate (TDI) or vehicle (acetone olive oil), followed by two ip injections of cyclophosphamide (CP, days 11 and 13), or one iv injection of antigranulocyte receptor 1 (aGR1, day 13) monoclonal antibody (mAb), or two ip injections of Ly6G-specific mAb (1A8, days 13 and 14). On day 15, the mice were challenged (oropharyngeal administration) with TDI or vehicle. The next day, we assessed methacholine airway hyperreactivity (AHR); bronchoalveolar lavage differential cell count; histopathology and total serum IgE; and auricular lymphocyte subpopulations and release of interleukin (IL)-2, IL-4, IL-10, IL-13, and gamma interferon by these lymphocytes. CP depleted all leukocyte types and completely prevented AHR and airway inflammation. aGR1 depleted granulocytes and CD8(+) lymphocytes, which resulted in a partial prevention in AHR but no decrease in airway inflammation. Depletion of Ly6G-positive granulocytes, i.e., both neutrophils and eosinophils, prevented AHR and lung epithelial damage and significantly reduced airway inflammation. Injection of aGR1 or 1A8 led to significantly changed cytokine release patterns in TDI-treated mice. Granulocytes, both neutrophils and eosinophils, are key cellular players in this model of chemical-induced asthma.

Monoclonal antibodies for the treatment of asthma

Asthma is a chronic inflammatory disease of the airways which can have a detrimental effect on quality of life and in extreme cases cause death. Although the majority of patients can control their asthma symptoms with a combination of steroids and beta agonists there is still a group of patients whose asthma remains symptomatic despite the best available treatment. These severe asthmatic patients represent the unmet medical need in asthma and are the focus of those developing novel monoclonal antibody based drugs. The complex networks of cytokines and cells involved in the pathology of asthma provide plenty of scope for intervention with monoclonal antibody based drugs which are able to block cytokine or chemokine receptor interactions, deplete cells expressing a specific receptor or block cell/cell interactions. At present anti-IgE (Xolair©) is the only monoclonal antibody based drug approved for the treatment of asthma. However, a number of other antibody based drugs have been clinically tested in asthma including anti-IL-5, anti-IL-4, anti-IL-13, anti-TNFα, anti-CCR3, anti-CCR4 and anti-OX40L. This review will examine the development of these monoclonal antibody based therapies. Since many of these therapies have targeted key pathways in asthma pathology these studies provide information on patient stratification and asthma pathology.

Chemokine expression by small sputum macrophages in COPD

Small sputum macrophages represent highly active cells that increase in the airways of patients with inflammatory diseases such as chronic obstructive pulmonary disease (COPD). It has been reported often that levels of cytokines, chemokines and pro-teases are increased in sputum supernatants of these patients. In COPD, the small sputum macrophages may contribute to these supernatant proteins and recruit additional cells via specific chemokine expression patterns. We therefore investigated the expression profile of chemokines in sputum macrophages obtained from COPD patients in comparison to cells from healthy donors and cells isolated after inhalation of lipopolysaccharide (LPS). We used the minimally invasive procedure of sputum induction and have purified macrophages with the RosetteSep technology. Using macrophage purification and flow cytometry we show that in COPD small sputum macrophages account for 85.9% ± 8.3% compared with 12.9% ± 7.1% of total macrophages in control donors. When looking at chemokine expression we found, for the small macrophages in COPD, increased transcript and protein levels for CCL2, CCL7, CCL13 and CCL22 with a more than 100-fold increase for CCL13 mRNA (P < 0.001). Looking at active smokers without COPD, there is a substantial increase of small macrophages to 60% ± 15% and, here, chemokine expression is increased as well. In a model of airway inflammation healthy volunteers inhaled 20 μg of lipopolysaccharide (LPS), which resulted in an increase of small sputum macrophages from 18% ± 19% to 64% ± 25%. The pattern of chemokine expression was, however, different with an upregulation for CCL2 and CCL7, while CCL13 was downregulated three-fold in the LPS-induced small macrophages. These data demonstrate that sputum macrophages in COPD show induction of a specific set of CCL chemokines, which is distinct from what can be induced by LPS.

Immunobiology of asthma

Asthma is characterized by chronic inflammation of the airways in which there is an overabundance of eosinophils, mast cells, and activated T helper lymphocytes. These inflammatory cells release mediators that then trigger bronchoconstriction, mucus secretion, and remodeling. The inflammatory mediators that drive this process include cytokines, chemokines, growth factors, lipid mediators, immunoglobulins, and histamine. The inflammation in allergic asthma can be difficult to control. This is mainly due to the development of an adaptive immunity to an allergen, leading to immunological memory. This leads to recall reactions to the allergen, causing persistent inflammation and damage to the airways. Generally, in asthma inflammation is directed by Th2 cytokines, which can act by positive feedback mechanisms to promote the production of more inflammatory mediators including other cytokines and chemokines. This review discusses the role of cytokines and chemokines in the immunobiology of asthma and attempts to relate their expression to morphological and functional abnormalities in the lungs of asthmatic subjects. We also discuss new concepts in asthma immunology, in particular the role of cytokines in airway remodeling and the interaction between cytokines and infection.

Alveolar macrophage subpopulations in bronchoalveolar lavage and induced sputum of asthmatic and control subjects

BACKGROUND

Alveolar macrophages (AM) are the most numerous immune cells in the airways and are involved in the immunological homeostasis of the lung. Intriguingly, their role in asthma remains unclear probably, in part, because of their heterogeneity.

OBJECTIVE

To characterize AM population from bronchoalveolar lavage (BAL) and induced sputum (IS) of asthmatic and normal subjects using specific biomarkers.

METHODS

Non-asthmatic non-allergic and allergic mild asthmatic subjects were recruited for this study. AM were obtained from BAL and IS and cytospins were prepared. Immunocytochemistry was performed for nine cellular markers (CD68, RFD7, CD14, CD11b, CD83, CD64, CD80, CD86, and FIZZ1).

RESULTS

Asthmatic subjects had more AM RFD7(+) in BAL compared with IS, whereas control subjects had more AM RFD7(+) in IS than in BAL. Consequently, there was an increased number of AM RFD7(+) in BAL of asthmatic subjects compared with BAL of control subjects. AM CD11b(+) was higher in BAL than in IS in both groups. The expression of FIZZ1, marker of macrophage alternative activation, was similar in asthmatic and normal subjects.

CONCLUSION

The expression of cellular markers on AM differs according to their localization in the lung. Subpopulations of AM may contribute to the inflammatory profile observed in asthmatic subjects.

Serum concentration of C-reactive protein is not a good marker of bronchial hyperresponsiveness

Introduction:

Asthmatic inflammation is responsible for vital features of the disease, including bronchial hyperresponsiveness (BHR). At present we do not have precise markers for monitoring asthmatic inflammation. C-reactive protein (CRP), a marker of systemic inflammation, seemed to be a factor which could also reflect the level of asthmatic inflammation expressed by BHR. Therefore the relationship between CRP concentration and BHR was evaluated.

Materials and Methods:

One hundred and two patients entered the study. A skin prick test with a broad spectrum of common aeroallergens as well as baseline spirometry and a histamine bronchoprovocation test were performed in each subject. Blood samples for high-sensitivity CRP (hsCRP) measurement were taken before the bronchial challenge tests.

Results:

Serum hsCRP concentrations ranged from 0.20 to 14.5 mg/l (median: 1.2 mg/l, 25–75% quartiles: 0.6–2.4). Positive skin prick tests were found in 26 subjects. Bronchial hyperresponsiveness was confirmed in 42 patients (first subgroup), while 60 subjects did not demonstrate BHR (second subgroup). Among the patients with BHR, asthma was diagnosed in 33 cases and Corrao syndrome in 9. In both subgroups, serum hsCRP concentrations had similar levels (median: 1.4 mg/l, 25–75% quartiles: 0.8–2.4 and median: 0.9 mg/l, 25–75% quartiles: 0.5–2.8, respectively; p=0.297). There was no statistically significant correlation (r= −0.163, p=0.302) between serum hsCRP concentration and the level of BHR expressed as the 20% provocative concentration for histamine. In addition, hsCRP serum concentration, after adjustment for age, atopy, body mass index, and gender, was not a significant predictor of positive histamine bronchoprovocation test results (p=0.22, OR=0.86, 95% CI).

Conclusions:

Serum hsCRP concentration is not a good marker of BHR, which is mainly dependent on asthmatic inflammation and is measured during bronchial challenge with histamine. This finding is important for interpreting and discussing results obtained from epidemiological and population-based studies on relationships between either CRP concentration and BHR or local and systemic inflammation.

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.

High serum levels of tumour necrosis factor-alpha and interleukin-8 in severe asthma: markers of systemic inflammation?

BACKGROUND

Severe asthma is characterized by elevated levels of pro-inflammatory cytokines and neutrophilic inflammation in the airways. Blood cytokines, markers of 'systemic' inflammation, may be a feature of amplified inflammation in severe asthma.

OBJECTIVE

To detect differences in IL-8, TNF-alpha, IL-16 and IL-13 levels in the serum(s) of stable severe and mild-moderate asthmatics related to blood leucocytes proportion, airway calibre and exhaled nitric oxide (NO) levels.

METHODS

We assessed cytokine serum levels by ELISA and blood leucocyte counts by an alkaline peroxidase method in 20 healthy controls, 22 mild-moderate [forced expiratory volume in 1 s (FEV1)(%pred): 89+/-3] and 14 severe asthmatics [FEV1(%pred): 49+/-2].

RESULTS

IL-8 and TNF-alpha levels were higher in severe asthmatics than in mild-moderate asthmatics or in controls (P<0.05). No differences in IL-16 and IL-13 levels were detected. Severe asthmatics showed higher circulating neutrophil and eosinophil number than controls (P<0.05). In severe asthmatics, exhaled NO levels were superior than in controls (P<0.05), but inferior than in mild-moderate asthmatics (P<0.05). We found positive correlation between TNF-alpha levels and exhaled NO (r=0.67; P=0.01) or circulating neutrophil counts (r=0.57; P=0.03) in severe asthmatics.

CONCLUSION

sTNF-alpha and sIL-8 are markers of 'systemic' inflammation in severe asthmatics, in conjunction with augmented circulating neutrophils, suggesting the involvement of neutrophil-derived cytokine pattern in severe asthma.

The role of interleukin-16 in eosinophilic chronic rhinosinusitis

Eosinophilic granulocytes (Eos) are found in great numbers both in the tissue and in the mucus of patients suffering from chronic rhinosinusitis with polyposis (ECRS). Interleukin-16 (IL-16) is known as a highly potent chemotactic and chemoattractant molecule (ED 10-11) for Eos. In an open, explorative, controlled study we examined the presence of IL-16 in mucosa tissue, mucus and serum in patients suffering from ECRS and its association to Eos activation. Tissue and nasal mucus specimen from 10 previously untreated, non allergic ECRS-patients undergoing paranasal sinus surgery and from 10 healthy non sinusitis subjects, undergoing nasal surgery because of anatomic nasal obstruction were investigated by real-time (RT-) PCR targeting human IL-16 mRNA. Haematoxylin-eosin (HE) staining and immunohistochemistry of formalin embedded tissue and mucus were applied for detection and determination of the proportion of activated Eos (aEos) and IL-16. Serum IL-16 was analyzed by enzyme-linked-immunosorbent assay (ELISA). IL-16 mRNA and IL-16 protein levels were elevated in nasal mucus, polyp tissue and in the serum of ECRS patients compared to healthy controls. There was a high proportion of aEos in ECRS patients compared to healthy subjects. Serum IL-16, IL-16 mRNA expression and IL-16 protein in mucus and tissue specimens were significantly associated with the presence of aEos in polyps of ECRS patients. Immunohistochemically IL-16 protein was mainly expressed in aEos, mast cells, lymphocytes and epithelial cells. In conclusion our data indicate that IL-16 may stimulate the migration and persistence of activated Eos in ECRS. IL-16 production in ECRS patients is not mediated by Immunglobuline-E (IgE).

Effect of formaldehyde on asthmatic response to inhaled allergen challenge

BACKGROUND

Exposure to formaldehyde may lead to exacerbation of asthma.

OBJECTIVES

Our aim in this study was to investigate whether exposure to a low level (500 microg/m(3)) of formaldehyde enhances inhaled allergen responses.

METHODS

Twelve subjects with intermittent asthma and allergy to pollen were exposed, at rest, in a double-blind crossover study to either formaldehyde or purified air for 60 min. The order of exposure to formaldehyde and air-only was randomized, and exposures were separated by 2 weeks. We also performed an allergen inhalation challenge after each exposure. Airway responsiveness to methacholine and lower airway inflammation (induced sputum) were assessed 8 hr after allergen challenge.

RESULTS

The median dose of allergen producing a 15% decrease in forced expiratory volume in 1 sec (PD(15)FEV(1)) was 0.80 IR (index of reactivity) after formaldehyde exposure compared with 0.25 IR after air-only exposure (p = 0.06). Formaldehyde exposure did not affect allergen-induced increase in responsiveness to methacholine (p = 0.42). We found no formaldehyde-associated effect on the airway inflammatory response, in particular the eosinophilic inflammatory response, induced by the allergen challenge 8 hr before.

CONCLUSION

In this study, exposure to 500 microg/m(3) formaldehyde had no significant deleterious effect on airway allergen responsiveness of patients with intermittent asthma; we found a trend toward a protective effect.

Significance of interleukin-16, macrophage-derived chemokine, eosinophil cationic protein and soluble E-selectin in reflecting disease activity of atopic dermatitis--from laboratory parameters to clinical scores

BACKGROUND

The search for the ideal clinical score reflecting atopic dermatitis (AD) severity has developed in parallel with unveiling key events in disease pathogenesis and finding laboratory parameters for monitoring disease activity. A major difficulty in assessing the relevance of reported serum markers of AD severity is the use of nonvalidated referent tools, which compromises comparison of results across studies.

OBJECTIVES

The aim of our study was to compare the significance of serum levels of interleukin (IL)-16, macrophage-derived chemokine (MDC), soluble E-selectin (sE-selectin) and eosinophil cationic protein (ECP) in reflecting AD severity and identify the most relevant parameter for monitoring the course of disease. Serum levels were tested against the same referent severity score in the same time frame and group of patients.

METHODS

The Severity Scoring of Atopic Dermatitis (SCORAD) index was used for assessment of disease severity in 21 adult patients in acute stage of AD and after complete resolution of clinical findings. Serum levels of IL-16, MDC, ECP and sE-selectin were measured at the same time points in 18 patients and compared with healthy nonatopic controls. The correlation between SCORAD and each laboratory parameter was tested for significance and compared.

RESULTS

Serum levels of IL-16, MDC, ECP and sE-selectin were significantly higher in patients in acute stage of AD compared with controls and decreased significantly after treatment, in parallel with clinical improvement. All monitored parameters reflected disease severity assessed by the clinical score. We found the highest significance level of correlation with SCORAD for IL-16 (r = 0.68, P =0.0019), followed by ECP (r = 0.65, P = 0.0032) and MDC (r = 0.55, P =0.0326). There was significant correlation between serum levels of IL-16 and MDC (r = 0.53, P = 0.0443) and ECP and sE-selectin (r = 0.48, P = 0.0427).

CONCLUSIONS

The study established a significant correlation between serum levels of IL-16 and SCORAD in adult AD patients. We report a significant correlation between IL-16 and MDC, both T-helper 2 activation markers. Our data suggested that IL-16 reflects most convincingly disease severity and may be used as a marker in clinical studies preferentially in combination with a clinical activity score.

A potent human anti-eotaxin1 antibody, CAT-213: isolation by phage display and in vitro and in vivo efficacy

The CC chemokine, eotaxin1 (CCL11) is an important regulator of eosinophil function. A marked accumulation of eosinophils in tissues has been correlated with the up-regulation of eotaxin1 expression in several diseases. The potential therapeutic value of neutralizing the effects of eotaxin1 in inflammatory conditions (including asthma) is under investigation. A human single-chain fragment variable antibody that neutralizes human eotaxin1 (CAT-212) was produced using antibody phage display and converted to whole antibody IgG4 format (CAT-213). A novel approach to lead optimization in which the length of the variable heavy chain complementarity-determining region 3 was reduced by one amino acid resulted in an increase in potency of >1000-fold compared with the parent anti-eotaxin1 antibody. The optimized antibody binds eotaxin1 with high affinity (80.4 pM) and specificity. CAT-213 and CAT-212 do not bind or neutralize a range of other human proteins including human monocyte chemoattractant protein-1, a structurally similar chemokine. CAT-213 neutralizes the ability of eotaxin1 to cause an increase in intracellular calcium signaling (with an IC(50) value of 2.86 nM), migration of CCR3-expressing L1.2 cells (with an IC(50) value of 0.48 nM), and inhibition of the eotaxin1-evoked shape change of human eosinophils in vitro (with an IC(50) of 0.71 nM). Local administration of CAT-213 to mice (1-100 microg kg(-1)) attenuates dermal eosinophilia induced by human eotaxin1, achieving >90% inhibition of eosinophil influx. CAT-213 may therefore be of therapeutic value in inhibiting diseases in which eotaxin1 and eosinophils play a major role, for example, severe asthma.

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.

Comparison of plasma eotaxin family level in aspirin-induced and aspirin-tolerant asthma patients

STUDY OBJECTIVE

Eosinophilic infiltration of airway tissue is a central feature of aspirin-induced asthma (AIA). Eotaxins belong to the family of CC chemokines, which coordinate the recruitment of inflammatory cells bearing chemokine (C-C motif) receptor-3 to sites of allergic inflammation. In the present study, the levels of eotaxin-1, eotaxin-2, and eotaxin-3 following an oral aspirin provocation test (APT) were measured, and the relationship between the eotaxin level and clinical parameters in patients with asthma was evaluated.

PATIENTS AND DESIGN

An APT was performed in patients with asthma. Twenty AIA patients and 23 aspirin-tolerant asthma (ATA) patients were identified. Plasma levels of eotaxin-1, eotaxin-2, and eotaxin-3 levels were measured by enzyme-linked immunosorbent assay in the 43 patients with asthma and in 39 control subjects.

RESULTS

The proportion of blood eosinophils was significantly higher in asthmatic patients than in control subjects. Nasal polyps were more common in AIA patients than in ATA patients (p < 0.05). In addition, the eotaxin-1 level was higher in AIA and ATA patients than in control subjects (p < 0.01 for each). The eotaxin-2 level was higher in ATA patients than in either the AIA patients (p < 0.05) or control subjects (p < 0.01). Similarly, the eotaxin-3 level was higher in ATA patients than in control subjects. A trend toward higher plasma levels of eotaxin-1 and eotaxin-3 at baseline and at 4 h after APT administration in the ATA group was noted but was not significant. Eotaxin-2 was also higher in ATA patients than in AIA patients at baseline and at 4 h after the APT.

CONCLUSION

This study shows that eotaxin-2 is differentially secreted in patients with asthma according to aspirin intolerance, and that secretion is not time-dependent in response to the APT in AIA and ATA patients. It therefore appears that eotaxin-2 may be up-regulated and may act differentially in patients with ATA.

Comparison of cell fixation methods of induced sputum specimens: an immunocytochemical analysis

Induced sputum (IS) is a non-invasive method to evaluate airway inflammation. Various techniques are used to fix IS cells but their respective value has never been compared. We aimed to determine the best IS cell fixation technique for cellular markers staining. Cells were fixed using four methods: 1) periodate-paraformaldehyde-lysine (PLP)-sucrose, 2) paraformaldehyde 4% on slide and 3) in solution and 4) acetone-methanol. Analysis was based on percentage of positive cells compared to total cell counts stained by hematoxylin and quality of staining. Using PLP-sucrose resulted in a higher percentage of positive cells for CD3 and a better quality of staining. Acetone-methanol showed a lower percentage of positive cells for CD68 and a poor quality. PLP-sucrose gives the best results for the preservation of the studied cell markers and acetone-methanol the worst.

Expression of interleukin-16 in allergic rhinitis

BACKGROUND

Interleukin-16 (IL-16) has been characterized as a chemoattractant for a variety of CD4+ T cells. Several inflammatory diseases, including allergic disorders, have been reported to correlate with IL-16. We first examined the IL-16 expression of serum and mucosal tissue in patients with allergic rhinitis.

METHODS

Forty-eight patients with a clinical history of house dust mite (HDM) or pollen-sensitive allergic rhinitis were included in this study. Serum IL-16 was analyzed by enzyme-linked immunosorbent assay (ELISA). IL-16 expression of nasal mucosa was detected by immunohistochemistry.

RESULTS

IL-16 levels were elevated in the serum of patients with allergic rhinitis compared with normal controls. In particular, serum IL-16 levels in HDM-sensitive patients were higher than those in pollen-sensitive patients. IL-16 was significantly correlated with eosinophils in the peripheral blood of allergic rhinitis patients. Histologically, IL-16 was expressed in infiltrated lymphocytes and nasal gland cells.

CONCLUSIONS

Our data indicate that one of the sources of elevated serum IL-16 in allergic patients may be gland cells and lymphocytes in allergic nasal mucosa. This IL-16 cytokine may be strongly associated with the developmental mechanism of allergic rhinitis.

Interleukin-16 expression and release in bullous pemphigoid

Cutaneous infiltration of activated CD4(+) T cells and eosinophils is an early event in blister formation during bullous pemphigoid (BP), suggesting that the trafficking of circulating leucocytes through the sites of inflammation, their activation and cytokine release is crucial in the pathogenesis of the disease. IL-16 is a major chemotactic factor able to recruit CD4(+) cells in the skin during inflammation and to induce the expression of functional high-affinity interleukin (IL)-2 receptors, thus contributing to cellular activation and proliferation. We performed a study in order to evaluate the presence of IL-16 in skin samples and sera and blister fluids of patients affected with BP in active phase of the disease (n = 39), compared with healthy donors studied as control group. Ten patients were also evaluated before and after steroid therapy. Our results demonstrated that IL-16 was expressed strongly by keratinocytes and by dermal infiltrating CD4(+) T lymphocytes in lesional skin of BP patients. High levels of IL-16 were detected in sera and blisters of BP, significantly higher in respect to healthy donors. When patients were investigated for the presence of eosinophil cationic protein (ECP) and soluble CD30 (sCD30) to reveal signs of eosinophils and Th2-cells activation, we found a positive correlation between IL-16 serum levels and both ECP and sCD30, suggesting that IL-16 is involved in Th2 lymphocytes and eosinophils recruitment during BP.

Monocyte chemotactic protein-4 (MCP-4; CCL-13): a biomarker of asthma

Airway expression of monocyte chemotactic protein-4 (MCP-4; CCL-13) is known to be increased in asthmatic airways where it is induced by proallergic cytokines, but the relationship of its systemic expression to asthma and naturally occurring exacerbations is unknown. We determined plasma levels of MCP-4 in 356 individuals with chronic-stable asthma and 240 normal subjects and compared plasma levels of MCP-4 in 30 patients who presented for emergent treatment of asthma with levels in 90 subjects with chronic-stable asthma matched for age, gender, and ethnicity. Median plasma MCP-4 levels were higher in patients with chronic-stable asthma than in normal subjects (399 vs. 307 pg/mL) (p < 0.001). In our entire cohort (n = 596), subjects with an MCP-4 > 218 pg/mL were at increased risk of asthma (p < 0.001 odds ratio, 3.26; 95% CI, 2.22-4.79). Logistic regression identified MCP-4 as an independent predictor of asthma diagnosis. The MCP-4 levels are higher in individuals with an acute asthma exacerbation than in subjects with chronic-stable asthma (513 vs. 355 pg/mL) (p = 0.002). The MCP-4 is a systemically expressed biomarker that independently predicts susceptibility to asthma and is directly associated with exacerbations. Elevated MCP-4 levels identify a group of asthmatics with systemic evidence of allergic inflammation who may be at risk for exacerbations or may benefit from abrogation of MCP-4.

FcepsilonRI-FcgammaRII coaggregation inhibits IL-16 production from human Langerhans-like dendritic cells

Langerhans-like dendritic cells (LLDC) express the high-affinity IgE receptor FcepsilonRI form that lacks the beta-chain, and may play an important role in allergic inflammation via production of IL-16. Secretion of mediators by human mast cells and basophils is mediated through FcepsilonRI and is decreased by coaggregating these receptors to the low-affinity IgG receptor, FcgammaRII. We used a recently described human Ig fusion protein (GE2), which is composed of key portions of the human gamma1 and the human epsilon heavy chains, to investigate its ability to inhibit IL-16 production from FcepsilonRI-positive Langerhans-like dendritic cells through coaggregation of FcgammaRII and FcepsilonRI. Unstimulated LLDC-derived from CD14-positive monocytes from atopic donors were shown to express FcgammaRII, an ITIM-containing receptor, but not FcepsilonRI or FcgammaRIII which are activating (ITAM) receptors. When passively sensitized with antigen-specific, human IgE and then challenged with antigen, LLDC were stimulated to produce IL-16. However, when FcepsilonRI and FcgammaRII were coaggregated with GE2, IL-16 production was significantly inhibited. Exposure of LLDCs to GE2 alone did not induce IL-16 production. Our results further extend our studies demonstrating the ability of GE2 to inhibit FcepsilonRI-mediated responses through coaggregation with FcgammaRIIB and at the same time show that human LDCC can be modulated in a fashion similar to mast cells and basophils.

T helper type 2 cytokine receptors and associated transcription factors GATA-3, c-MAF, and signal transducer and activator of transcription factor-6 in induced sputum of atopic asthmatic patients

BACKGROUND

It is well-known that the expression of T helper (Th) type 2 cytokines such as interleukin (IL)-4 and IL-5, and their receptors, is up-regulated within the airways of allergic asthmatic patients. Furthermore, higher numbers of cells producing GATA-3, c-MAF, and signal transducer and activator of transcription factor (STAT)-6, which are transcription factors (TFs) that are implicated in the regulation and signaling of the Th2 cytokines, have been observed in bronchial biopsy specimens from asthmatic patients but not in those of healthy control subjects.

METHODS

We examined whether these mediators also can be detected in induced sputum. Immunoreactivity for IL-4Ralpha, IL-5Ralpha, GATA-3, c-MAF, and STAT-6 was investigated in samples of induced sputum from asthmatic patients (n = 8) and healthy control subjects (n = 8).

RESULTS

Our results showed that the numbers of cells expressing IL-4 receptor alpha (Ralpha) and IL-5Ralpha were higher in samples from asthmatic patients compared to those of control subjects (p < 0.01). More cells exhibiting GATA-3, c-MAF, and STAT-6 immunoreactivity also were found in asthmatic patients vs those in control subjects (p < 0.005). Furthermore, the expression of STAT-6 and IL-4Ralpha, GATA-3 and IL-5Ralpha, and c-MAF with both IL-4Ralpha and IL-5Ralpha was correlated (p < 0.05).

CONCLUSIONS

This study demonstrated that induced sputum provides sufficient sensitivity for examining the pathways of cytokine signaling, cytokine receptor signaling, and intracellular signaling. Furthermore, these data show correlations between the expression of Th2 cytokine receptors and associated TFs in the human lung, which has not been documented previously.

Neutrophils in asthma pathophysiology

Although the role of eosinophils, mast cells, and T cells in asthma has long been recognized, several reports suggest that neutrophils may also be involved. In most studies of people with mild asthma, neutrophil numbers in the airways are not different from controls. However, in severe asthma, including asthma deaths, neutrophils are usually raised. Furthermore, most pediatric studies suggest that neutrophils are raised in some children, in particular in the young or infantile wheeze group. Measurements of inflammatory mediators in the airways of asthmatic subjects suggest that neutrophils are activated.

Sputum eosinophilia and maximal airway narrowing in Dermatophagoides pteronyssinus allergic rhinitis patients: only rhinitis or rhinitis plus mild asthma?

STUDY OBJECTIVE

To study the existence of bronchial disease among rhinitis patients. To evaluate the laboratory test or set of tests (ie, symptoms, exposure, and sensitization to the allergen, and the provocative dose of methacholine [Mth] causing a 20% fall in FEV(1) [PD(20)] and the maximal response plateau [MRP] to Mth) that best identifies a case of mild asthma.

DESIGN

Cross-sectional analysis in 52 Dermatophagoides pteronyssinus-monosensitized patients who were consulting a physician for perennial rhinitis.

SETTING

Allergy Department, Hospital Doctor Negrín, Las Palmas, Grand Canary Island, Spain.

INTERVENTIONS AND MEASUREMENTS

Patients filled out a standardized asthma symptom questionnaire, and underwent sputum induction and Mth challenge in which 40% falls in FEV(1) were attained. Dose-response curves were expressed in terms of both PD(20) values and the level of the MRP. D pteronyssinus allergen exposure was assessed in dust samples from patients' beds.

RESULTS

No difference between patients who positively responded to the questionnaire and those who did not was observed. Mth-PD(20) values were not detected in 13% of the patients reporting bronchial symptoms, and an MRP was not identified in 59% of the subjects who did not respond positively. A higher degree of allergen sensitization (ascertained from skin test results, and total and specific serum IgE levels) and higher degree of sputum eosinophilia were detected in subjects in whom an MRP had not been identified. The presence of sputum eosinophilia provided the best differentiation between those patients who presented with an MRP and those who did not.

CONCLUSION

The individual perception of bronchial symptoms is highly variable among perennial allergic rhinitis patients. The lack of a maximal airway-narrowing plateau is related to the presence of sputum eosinophilia, which might be useful in the detection of patients susceptible to anti-inflammatory therapy. Prospective studies evaluating whether these patients are more likely to develop symptomatic asthma in the future and if the early anti-inflammatory treatment prevents its development are needed.

Circulating interleukin 16 (IL-16) in children with atopic/eczema dermatitis syndrome (AEDS): a novel serological marker of disease activity

BACKGROUND

Chemokines play a central role in atopic eczema/dermatitis syndrome (AEDS). Interleukin 16 (IL-16) has been described as a main cytokine involved in CD4+ cell recruitment during inflammation. Recently the influx of CD4+ lymphocytes has been related to the up-regulation of IL-16 in AEDS skin lesions. Circulating beta-chemokines (Eotaxin and RANTES) and IL-16 were investigated in children with AEDS to correlate their presence with the severity of the disease. We also measured serum levels of soluble CD30 (sCD30), a marker of Th2 immune responses related to AEDS disease activity.

METHODS

Serum levels of eotaxin, RANTES, IL-16 and sCD30 were measured by immunoenzymatic assay in paediatric patients with pure AEDS (pAEDS, n = 39); the severity of the disease was graded by SCORAD. Fifteen children with AEDS in presence of respiratory allergy (AEDS+A), 15 with allergic asthma (A) and 20 age-matched healthy donors were investigated as control groups.

RESULTS

When compared to normals, high amounts of Eotaxin and IL-16 were detected in sera of pAEDS (P = 0.002; P < 0.0001), AEDS+A (P = 0.02; P = 0.01) and A patients (P = 0.004; P = 0.03) with respect to normals. Serum levels of RANTES were also elevated in pAEDS patients, significantly higher than normals (P = 0.009), whereas no statistically significant differences could be detected between pAEDS and AEDS+A or A groups. IL-16 was progressively increased in the different stages of pAEDS, with a positive correlation between IL-16 and both SCORAD and sCD30 (P < 0.0001).

CONCLUSION

We suggest that IL-16 could serve as a useful marker of disease activity in childhood pAEDS.

IL-16 promotes leukotriene C(4) and IL-4 release from human eosinophils via CD4- and autocrine CCR3-chemokine-mediated signaling

Human eosinophils are potential sources of inflammatory and immunomodulatory mediators, including cysteinyl leukotrienes, chemokines, and cytokines, which are pertinent to allergic inflammation. We evaluated the means by which IL-16, a recognized eosinophil chemoattractant, might act on eosinophils to affect their capacity to release leukotriene C(4) (LTC(4)) or their preformed stores of chemokines (eotaxin, RANTES) or Th1 (IL-12) or Th2 (IL-4) cytokines. IL-16 dose dependently (0.01-100 nM) elicited new lipid body formation, intracellular LTC(4) formation at lipid bodies, and priming for enhanced calcium ionophore-activated LTC(4) release. IL-16 also elicited brefeldin A-inhibitable, vesicular transport-mediated release of preformed IL-4, but not IL-12, from eosinophils. CD4 is a recognized IL-16R, and accordingly anti-CD4 Fab, soluble CD4, and a CD4 domain 4-based IL-16 blocking peptide inhibited the actions of IL-16 on eosinophils. Although CD4 is not G-protein coupled, pertussis toxin inhibited IL-16-induced eosinophil activation. IL-16 actions were found to be mediated by the autocrine activity, not of platelet-activating factor, but rather of endogenous CCR3-acting chemokines. IL-16 induced the rapid vesicular transport-mediated release of RANTES. The effects of IL-16 were blocked by CCR3 inhibitors (met-RANTES, anti-CCR3 mAb) and by neutralizing anti-eotaxin and anti-RANTES mAbs, but not by platelet-activating factor receptor antagonists (CV6209, BN52021). RANTES and eotaxin each enhanced LTC(4) and IL-4 (but not IL-12) release. Therefore, IL-16 activation of eosinophils is CD4-mediated to elicit the extracellular release of preformed RANTES and eotaxin, which then in an autocrine fashion act on plasma membrane CCR3 receptors to stimulate both enhanced LTC(4) production and the preferential release of IL-4, but not IL-12, from within eosinophils.