The role of adhesion molecules in human eosinophil and basophil recruitment

PD-1 deficiency impairs eosinophil recruitment to tissue during Trichinella spiralis infection

Blockade of programmed cell death 1 (PD-1) is considered a promising strategy for controlling pathogen infection by enhancing host immune cell function. Eosinophils, which play a crucial role in type 2 immune responses, are essential components of the host defense against helminth infection. Here, we investigate the role of PD-1 in eosinophilia during Trichinella spiralis infection in mice. PD-1-deficient (PD-1-/-) mice exhibit delayed expulsion of adult worms and increased muscle larva burdens compared to wild-type mice following infection. Additionally, PD-1-/- mice display impaired recruitment of eosinophils to parasite-invaded tissues, attributed to decreased upregulation of adhesion molecules on both eosinophils and vascular endothelium after infection. The compromised Th2 cytokine response further contributes to impaired adhesion interactions, affecting eosinophil migration and cytotoxicity against larvae in vitro within T. spiralis-infected PD-1-/- mice. Our findings demonstrate a positive role for PD-1 in the recruitment of eosinophils, suggesting its involvement in host defense against helminth infection.

Thymic stromal lymphopoietin contributes to ozone-induced exacerbations of eosinophilic airway inflammation via granulocyte colony-stimulating factor in mice

BACKGROUND

Ozone is one of the triggers of asthma, but its impact on the pathophysiology of asthma, such as via airway inflammation and airway hyperresponsiveness (AHR), is not fully understood. Thymic stromal lymphopoietin (TSLP) is increasingly seen as a crucial molecule associated with asthma severity, such as corticosteroid resistance.

METHODS

Female BALB/c mice sensitized and challenged with house dust mite (HDM) were exposed to ozone at 2 ppm for 3 h. Airway inflammation was assessed by the presence of inflammatory cells in bronchoalveolar lavage fluid and concentrations of cytokines including TSLP in lung. Anti-TSLP antibody was administered to mice to block the signal. Survival and adhesion of bone marrow-derived eosinophils in response to granulocyte colony-stimulating factor (G-CSF) were evaluated.

RESULTS

Ozone exposure increased eosinophilic airway inflammation and AHR in mice sensitized and challenged with HDM. In addition, TSLP, but not IL-33 and IL-25, was increased in lung by ozone exposure. To confirm whether TSLP signaling is associated with airway responses to ozone, an anti-TSLP antibody was administered, and it significantly attenuated eosinophilic airway inflammation, but not AHR. Interestingly, G-CSF, but not type 2 cytokines such as IL-4, IL-5, and IL-13, was regulated by TSLP signaling associated with eosinophilic airway inflammation, and G-CSF prolonged survival and activated eosinophil adhesion.

CONCLUSIONS

The present data show that TSLP contributes to ozone-induced exacerbations of eosinophilic airway inflammation and provide greater understanding of ozone-induced severity mechanisms in the pathophysiology of asthma related to TSLP and G-CSF.

Origins and functions of eosinophils in two non-mucosal tissues

Eosinophils are a type of granulocyte named after the presence of their eosin-stained granules. Traditionally, eosinophils have been best known to play prominent roles in anti-parasitic responses and mediating allergic reactions. Knowledge of their behaviour has expanded with time, and they are now recognized to play integral parts in the homeostasis of gastrointestinal, respiratory, skeletal muscle, adipose, and connective tissue systems. As such, they are implicated in a myriad of pathologies, and have been the target of several medical therapies. This review focuses on the lifespan of eosinophils, from their origins in the bone marrow, to their tissue-resident role. In particular, we wish to highlight the functions of eosinophils in non-mucosal tissues with skeletal muscle and the adipose tissues as examples, and to discuss the current understanding of their participation in diseased states in these tissues.

Eosinophils-from cradle to grave: An EAACI task force paper on new molecular insights and clinical functions of eosinophils and the clinical effects of targeted eosinophil depletion

Over the past years, eosinophils have become a focus of scientific interest, especially in the context of their recently uncovered functions (e.g. antiviral, anti-inflammatory, regulatory). These versatile cells display both beneficial and detrimental activities under various physiological and pathological conditions. Eosinophils are involved in the pathogenesis of many diseases which can be classified into primary (clonal) and secondary (reactive) disorders and idiopathic (hyper)eosinophilic syndromes. Depending on the biological specimen, the eosinophil count in different body compartments may serve as a biomarker reflecting the underlying pathophysiology and/or activity of distinct diseases and as a therapy-driving (predictive) and monitoring tool. Personalized selection of an appropriate therapeutic strategy directly or indirectly targeting the increased number and/or activity of eosinophils should be based on the understanding of eosinophil homeostasis including their interactions with other immune and non-immune cells within different body compartments. Hence, restoring as well as maintaining homeostasis within an individual's eosinophil pool is a goal of both specific and non-specific eosinophil-targeting therapies. Despite the overall favourable safety profile of the currently available anti-eosinophil biologics, the effect of eosinophil depletion should be monitored from the perspective of possible unwanted consequences.

Eosinophilic Granulomatosis with Polyangiitis: Latest Findings and Updated Treatment Recommendations

Eosinophilic granulomatosis with polyangiitis (EGPA) causes necrotizing vasculitis and eosinophil-rich granulomatous inflammation in small- to medium-sized vessels, resulting in multiple organ damage. EGPA is classified as an antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, with myeloperoxidase-ANCA detected in approximately one-third of the patients. Conventional treatment of EGPA relies on systemic glucocorticoids (GCs) in combination with cyclophosphamide when poor prognostic factors are present; however, the dilemma between disease control and drug-related adverse effects has long been a challenge. Recent studies have revealed that the genetic background, pathophysiology, and clinical manifestations differ between ANCA-positive and ANCA-negative patients; however, mepolizumab, an interleukin (IL)-5 inhibitor, is effective in both groups, suggesting that the IL-5-eosinophil axis is deeply involved in the pathogenesis of both ANCA-positive and ANCA-negative EGPA. This review summarizes the latest knowledge on the pathophysiology of EGPA and focuses on the roles of eosinophils and ANCA. We then introduce the current treatment recommendations and accumulated evidence for mepolizumab on EGPA. Based on current unmet clinical needs, we discuss potential future therapeutic strategies for EGPA.

Eosinophils and Lung Cancer: From Bench to Bedside

Eosinophils are rare, multifunctional granulocytes. Their growth, survival, and tissue migration mainly depend on interleukin (IL)-5 in physiological conditions and on IL-5 and IL-33 in inflammatory conditions. Preclinical evidence supports an immunological role for eosinophils as innate immune cells and as agents of the adaptive immune response. In addition to these data, several reports show a link between the outcomes of patients treated with immune checkpoint inhibitors (ICI) for advanced cancers and blood eosinophilia. In this review, we present, in the context of non-small cell lung cancer (NSCLC), the biological properties of eosinophils and their roles in homeostatic and pathological conditions, with a focus on their pro- and anti-tumorigenic effects. We examine the possible explanations for blood eosinophilia during NSCLC treatment with ICI. In particular, we discuss the value of eosinophils as a potential prognostic and predictive biomarker, highlighting the need for stronger clinical data. Finally, we conclude with perspectives on clinical and translational research topics on this subject.

Eosinophils and eosinophil-associated disorders: immunological, clinical, and molecular complexity

Eosinophils and their mediators play a crucial role in various reactive states such as bacterial and viral infections, chronic inflammatory disorders, and certain hematologic malignancies. Depending on the underlying pathology, molecular defect(s), and the cytokine- and mediator-cascades involved, peripheral blood and tissue hypereosinophilia (HE) may develop and may lead to organ dysfunction or even organ damage which usually leads to the diagnosis of a HE syndrome (HES). In some of these patients, the etiology and impact of HE remain unclear. These patients are diagnosed with idiopathic HE. In other patients, HES is diagnosed but the etiology remains unknown — these patients are classified as idiopathic HES. For patients with HES, early therapeutic application of agents reducing eosinophil counts is usually effective in avoiding irreversible organ damage. Therefore, it is important to systematically explore various diagnostic markers and to correctly identify the disease elicitors and etiology. Depending on the presence and type of underlying disease, HES are classified into primary (clonal) HES, reactive HES, and idiopathic HES. In most of these patients, effective therapies can be administered. The current article provides an overview of the pathogenesis of eosinophil-associated disorders, with special emphasis on the molecular, immunological, and clinical complexity of HE and HES. In addition, diagnostic criteria and the classification of eosinophil disorders are reviewed in light of new developments in the field.

Elevated gaseous luminal nitric oxide and circulating IL-8 as features of Helicobacter pylori-induced gastric inflammation

BACKGROUND

Gastric nitric oxide (NO) production in response to Helicobacter pylori via inducible nitric oxide synthase (iNOS) is suggested as a biomarker of inflammation and cytotoxicity. The aim of this study was to investigate relationships between gastric [NO], immunological biomarkers and histopathology.

MATERIALS AND METHODS

Esophagogastroduodenoscopy was done in 96 dyspepsia patients. Luminal [NO] was measured by chemiluminescence. Biopsies were taken from gastric antrum and corpus for culture and histopathology. H. pylori IgG was detected by immunoblot assay. Biobanked plasma from 76 dyspepsia patients (11 H. pylori positives) was analyzed for 39 cytokines by multiplexed ELISA.

RESULTS

H. pylori-positive patients had higher [NO] (336 ± 26 ppb, mean ± 95% CI, n = 77) than H. pylori-negative patients (128 ± 47 ppb, n = 19) (P < 0.0001). Histopathological changes were found in 99% of H. pylori-positive and 37% of H. pylori-negative patients. Histopathological concordance was 78-100% between corpus and antrum. Correlations were found between gastric [NO] and severity of acute, but not chronic, inflammation. Plasma IL-8 (increased in H. pylori positives) had greatest difference between positive and negative groups, with eotaxin, MIP-1β, MCP-4, VEGF-A, and VEGF-C also higher (P < 0.004 to P < 0.032). Diagnostic odds ratios using 75% cut-off concentration were 7.53 for IL-8, 1.15 for CRP, and 2.88 for gastric NO.

CONCLUSIONS

Of the parameters tested, increased gastric [NO] and circulating IL-8 align most consistently and selectively in H. pylori-infected patients. Severity of mucosal inflammatory changes is proportional to luminal [NO], which might be tied to IL-8 production. It is proposed that IL-8 be further investigated as a blood biomarker of treatment outcomes.

Adhesion molecule cross-linking and cytokine exposure modulate IgE- and non-IgE-dependent basophil activation

Basophils are known for their role in allergic inflammation, which makes them suitable targets in allergy diagnostics such as the basophil activation test (BAT) and the microfluidic immunoaffinity basophil activation test (miBAT). Beside their role in allergy, basophils have an immune modulatory role in both innate immunity and adaptive immunity. To accomplish this mission, basophils depend on the capability to migrate from blood to extravascular tissues, which includes interactions with endothelial cells, extracellular matrix and soluble mediators. Their receptor repertoire is well known, but less is known how these receptor–ligand interactions impact the degranulation process and the responsiveness to subsequent activation. As the consequences of these interactions are crucial to fully appreciate the role of basophils in immune modulation and to enable optimization of the miBAT, we explored how basophil activation status is regulated by cytokines and cross‐linking of adhesion molecules. The expression of adhesion molecules and activation markers on basophils from healthy blood donors was analysed by flow cytometry. Cross‐linking of CD203c, CD62L, CD11b and CD49d induced a significant upregulation of CD63 and CD203c. To mimic in vivo conditions, valid also for miBAT, CD62L and CD49d were cross‐linked followed by IgE‐dependent activation (anti‐IgE), which caused a reduced CD63 expression compared with anti‐IgE activation only. IL‐3 and IL‐33 priming caused increased CD63 expression after IgE‐independent activation (fMLP). Together, our data suggest that mechanisms operational both in the microfluidic chip and in vivo during basophil adhesion may impact basophil anaphylactic and piecemeal degranulation procedures and hence their immune regulatory function.

Eosinophilic colitis: clinical review and 2020 update

Eosinophilic colitis (EC) is a rare inflammatory disease included in the chapter of eosinophilic gastrointestinal disorders (EGIDs), diagnosed by the presence of primary eosinophilic infiltrate in the colon wall in symptomatic patients. While the etiology of primary colonic eosinophilia is unknown, several conditions are involved in the pathogenesis of secondary eosinophilic colonic infiltrate (food allergens, parasitic infections, drugs), which have to be excluded in order to correctly diagnose the primary form of the disease. Up to now, EC is lacking of codified guidelines regarding diagnostic criteria (especially eosinophil threshold values) and treatment, thus a correct approach to EC remains very challenging. Imaging, laboratory tests and endoscopy might be helpful in ruling out other mimic conditions, but EC is still a diagnosis of exclusion. Several treatment options are feasible, but most of the evidences are drawn from case reports and small case series, thus limiting their value. We carried out a review of the current literature to evaluate the more appropriate and modern clinical strategy for diagnosis and management of EC.

Eosinophilic colitis: A clinical review

Eosinophilic colitis is a rare entity characterized by the presence of a high eosinophilic infiltrate into the colonic wall in symptomatic patients, more often presenting with abdominal pain or diarrhea. These characteristics distinguish eosinophilic colitis from primary colonic eosinophilia, in which patients are asymptomatic. Primary colonic eosinophilia does not need any therapy, while eosinophilic colitis requires a strict treatment, similar to that of the more codified chronic intestinal inflammatory diseases. To date the lack of codified guidelines regarding the diagnostic criteria and the eosinophil threshold values for each colonic segment are the main diagnostic challenge for eosinophilic colitis. In addition, eosinophilic colitis is a diagnosis of exclusion, once all other causes of colonic eosinophilia (food allergens, infections, drugs, etc.) have been excluded. Several treatment options are available for eosinophilic colitis, although the evidence for most of them is limited to case reports and small case series. We examine the epidemiology, etiology, pathophysiology, diagnostic criteria and therapeutic options of eosinophilic colitis reporting recent evidence from the current literature.

Airway Eosinophilopoietic and Autoimmune Mechanisms of Eosinophilia in Severe Asthma

Eosinophils are critical in asthma biology, contributing to symptoms, airflow obstruction, airway hyperresponsiveness, and remodeling. In severe asthma, in addition to local maturation in bone marrow, in situ eosinophilopoiesis plays a key role in the persistence of airway eosinophilia. Local milieu of structural, epithelial and inflammatory cells contribute by generating eosinophilopoietic cytokines in response to epithelial-derived alarmins. Another mechanism of persistent airway eosinophilia is glucocorticosteroid insensitivity, which is linked to recurrent airway infections and presence of local autoantibodies. Novel molecules are being developed to target specific immune pathways as potential steroid-sparing strategies.

Human Respiratory Syncytial Virus: Role of Innate Immunity in Clearance and Disease Progression

Human respiratory syncytial virus (HRSV) infections have worldwide records. The virus is responsible for bronchiolitis, pneumonia, and asthma in humans of different age groups. Premature infants, young children, and immunocompromised individuals are prone to severe HRSV infection that may lead to death. Based on worldwide estimations, millions of cases were reported in both developed and developing countries. In fact, HRSV symptoms develop mainly as a result of host immune response. Due to inability to establish long lasting adaptive immunity, HRSV infection is recurrent and hence impairs vaccine development. Once HRSV attached to the airway epithelia, interaction with the host innate immune components starts. HRSV interaction with pulmonary innate defenses is crucial in determining the disease outcome. Infection of alveolar epithelial cells triggers a cascade of events that lead to recruitment and activation of leukocyte populations. HRSV clearance is mediated by a number of innate leukocytes, including macrophages, natural killer cells, eosinophils, dendritic cells, and neutrophils. Regulation of these cells is mediated by cytokines, chemokines, and other immune mediators. Although the innate immune system helps to clear HRSV infection, it participates in disease progression such as bronchiolitis and asthma. Resolving the mechanisms by which HRSV induces pathogenesis, different possible interactions between the virus and immune components, and immune cells interplay are essential for developing new effective vaccines. Therefore, the current review focuses on how the pulmonary innate defenses mediate HRSV clearance and to what extent they participate in disease progression. In addition, immune responses associated with HRSV vaccines will be discussed.

ATP drives eosinophil effector responses through P2 purinergic receptors

BACKGROUND

Eosinophils recognize various stimuli, such as cytokines, chemokines, immunoglobulins, complement, and external pathogens, resulting in their accumulation in mucosal tissues and the progression of inflammation. Eosinophils are also involved in innate Th2-type immune responses mediated through endogenous danger signals, including IL-33, uric acid (UA), or ATP, in non-sensitized mice exposed to environmental allergens. However, the mechanism involved in eosinophil responses to these danger signals remains insufficiently understood.

METHODS

We examined migration, adhesion, superoxide production and degranulation of human eosinophils. Isolated eosinophils were incubated with monosodium urate (MSU) crystals and ATPγS, a non-hydrolysable ATP analogue. To determine the involvement of P2 or P2Y2 receptors in eosinophil responses to UA and ATP, eosinophils were preincubated with a pan-P2 receptor inhibitor, oxidized ATP (oATP), or anti-P2Y2 antibody before incubation with MSU crystals or ATPγS.

RESULTS

MSU crystals induced adhesion of eosinophils to recombinant human (rh)-ICAM-1 and induced production of superoxide. oATP abolished eosinophil responses to MSU crystals, suggesting involvement of endogenous ATP and its receptors. Furthermore, exogenous ATP, as ATPγS, induced migration of eosinophils through a model basement membrane, adhesion to rh-ICAM-1, superoxide generation, and degranulation of eosinophil-derived neurotoxin (EDN). oATP and anti-P2Y2 significantly reduced these eosinophil responses.

CONCLUSIONS

ATP serves as an essential mediator of functional responses in human eosinophils. Eosinophil responses to ATP may be implicated in airway inflammation in patients with asthma.

Allergic Respiratory Inflammation and Remodeling

Asthma and rhinitis are inflammatory diseases of the respiratory tract. Respiratory inflammation of the adaptive and innate immune system is the focus of this review, and chronic inflammation is not limited to the respiratory tissue. The inflammatory response, which consists of phagocytes, eosinophils, mast cells, and lymphocytes, spreads along the respiratory tract, leading to tissue damage. Mast cells and eosinophils are commonly recognized for their detrimental role in allergic reactions on activation through the high- and low-affinity receptors for IgE FcɛRI. These cells rapidly produce and secrete many of the mediators responsible for the typical symptoms of asthma and rhinitis. However, increasing amount of evidence demonstrate that mast cells and leukocytes have vital roles in host defense against pathogenesis. Histological methods are used to study leukocytes and receptor expression pattern in different respiratory tract compartments. The overall aim of this review was to understand the relationship between upper and lower respiratory tract inflammation and remodeling in patients with allergic and non-allergic asthma and rhinitis. In conclusion, this review discusses the relationship between the upper and lower airway in respiratory disease and focuses on the effect of respiratory processes on laryngeal inflammation, remodeling, function, and symptoms; however, they also have a central role in the initiation of the allergic immune response. Our findings suggest that there are differences that contribute to the development of immunopathological mechanisms of these clinically distinct forms of asthma, rhinitis, and chronic obstructive pulmonary disease.

Atopic dermatitis patients carrying G allele in -1082 G/A IL-10 polymorphism are predisposed to higher serum concentration of IL-10

INTRODUCTION

Atopic dermatitis (AD) is a chronic skin inflammatory disease in which Th2-derived cytokines play an essential role. Aim of the study was to assess interleukin 4, 10 and 13 (IL-4, IL-10 and IL-13) serum concentrations in AD patients and to correlate the values with the occurrence of genotypes of selected polymorphisms in genes encoding these cytokines.

MATERIAL AND METHODS

Seventy-six AD patients (mean age 11.4 years) and 60 healthy controls were enrolled in the study. Blood samples were analyzed for IL-4, IL-10 and IL-13 concentrations with ELISA assay and genotyping for -590C/T IL-4, -1082A/G IL-10 and -1055C/T IL-13 polymorphisms with PCR-RFLP.

RESULTS

The obtained results revealed statistically higher serum concentration of IL-10 and IL-13 in AD patients when compared to healthy controls (10.30 pg/ml vs. 8.51 pg/ml for IL-10 and 5.67 pg/ml vs. 4.98 pg/ml for IL-13). There were no significant differences between AD patients and controls in regard to IL-4 serum level (5.10 pg/ml vs. 7.1 pg/ml). Analyzing the association between level of the examined cytokines and genotype polymorphisms -590 C/T for the IL-4 gene, -1082 A/G for the IL-10 gene and -1055 C/T for the IL-13 gene, we found a statistically higher IL-10 serum level among carriers of the G allele in the -1082 G/A IL-10 polymorphism both in AD and control groups. We did not find any significant differences between serum level of IL-4 and IL-13 in regard to genotype occurrence in examined polymorphisms: -590 C/T for the IL-4 gene and -1055 C/T for the IL-13 gene.

CONCLUSIONS

The obtained results confirm the genetic background of IL-10 synthesis in the Polish population.

Effects of low level laser therapy on ovalbumin-induced mouse model of allergic rhinitis

Introduction. This study was designed to investigate the effects of low level laser therapy (LLLT) on experimental allergic rhinitis (AR) models induced by ovalbumin. Materials and Methods. AR was induced by 1% ovalbumin in mice. Twenty-four mice were divided into 4 groups: normal, control, low, and high dose irradiation. Low and high dose LLLT were irradiated once a day for 7 days. Total IgE, cytokines concentrations (IL-4 and IFN-γ), and thymus and activation regulated chemokine (TARC) were measured. Histological changes in the nasal mucosal tissue by laser irradiation were examined. Results. LLLT significantly inhibited total IgE, IL-4, and TARC expression in ovalbumin-induced mice at low dose irradiation. The protein expression level of IL-4 in spleen was inhibited in low dose irradiation significantly. IL-4 expression in EL-4 cells was inhibited in a dose dependent manner. Histological damages of the epithelium in the nasal septum were improved by laser irradiation with marked improvement at low dose irradiation. Conclusion. These results suggest that LLLT might serve as a new therapeutic tool in the treatment of AR with more effectiveness at low dose irradiation. To determine the optimal dose of laser irradiation and action mechanisms of laser therapy, further studies will be needed.

Markers of vascular perturbation correlate with airway structural change in asthma

RATIONALE

Air trapping and ventilation defects on imaging are characteristics of asthma. Airway wall thickening occurs in asthma and is associated with increased bronchial vascularity and vascular permeability. Vascular endothelial cell products have not been explored as a surrogate to mark structural airway changes in asthma.

OBJECTIVES

Determine whether reporters of vascular endothelial cell perturbation correlate with airway imaging metrics in patients with asthma of varying severity.

METHODS

Plasma from Severe Asthma Research Program subjects was analyzed by ELISAs for soluble von Willebrand factor mature protein (VWF:Ag) and propeptide (VWFpp), P-selectin, and platelet factor 4. Additional subjects were analyzed over 48 hours after whole-lung antigen challenge. We calculated ventilation defect volume by hyperpolarized helium-3 magnetic resonance imaging and areas of low signal density by multidetector computed tomography (less than -856 Hounsfield units [HU] at functional residual capacity and -950 HU at total lung capacity [TLC]).

MEASUREMENTS AND MAIN RESULTS

VWFpp and VWFpp/Ag ratio correlated with and predicted greater percentage defect volume on hyperpolarized helium-3 magnetic resonance imaging. P-selectin correlated with and predicted greater area of low density on chest multidetector computed tomography less than -950 HU at TLC. Platelet factor 4 did not correlate. Following whole-lung antigen challenge, variation in VWFpp, VWFpp/Ag, and P-selectin among time-points was less than that among subjects, indicating stability and repeatability of the measurements.

CONCLUSIONS

Plasma VWFpp and P-selectin may be useful as surrogates of functional and structural defects that are evident on imaging. The results raise important questions about why VWFpp and P-selectin are associated specifically with different imaging abnormalities.

Therapeutic targeting of eosinophil adhesion and accumulation in allergic conjunctivitis

Considerable evidence indicates that eosinophils are important effectors of ocular allergy. Increased worldwide prevalence of allergic eye pathologies has stimulated the identification of novel drug targets, including eosinophils and adhesion molecules. Accumulation of eosinophils in the eye is a key event in the onset and maintenance of allergic inflammation and is mediated by different adhesion molecules. Antihistamines with multiple mechanisms of action can be effective during the early and late phases of allergic conjunctivitis by blocking the interaction between β(1) integrins and vascular cell adhesion molecule (VCAM)-1. Small molecule antagonists that target key elements in the process of eosinophil recruitment have been identified and reinforce the validity of α(4)β(1) integrin as a therapeutic target. Glucocorticoids are among the most effective drugs for ocular allergy, but their use is limited by adverse effects. Novel dissociated glucocorticoids can prevent eosinophil accumulation and induce apoptosis of eosinophils, making them promising candidates for ophthalmic drugs. This article reviews recent understanding of the role of adhesion molecules in eosinophil recruitment in the inflamed conjunctiva along with effective treatments for allergic conjunctivitis.

Therapeutic concepts in adult and paediatric eosinophilic oesophagitis

Eosinophilic oesophagitis (EoE) was first described in the early 1990s. Although initially reported to be a rare entity, EoE has rapidly become a regularly diagnosed disease with a prevalence of approximately 1 in 2,000 individuals in the USA and Europe. The disease is characterized by a combination of oesophageal dysfunction and predominant eosinophilic infiltration of the oesophageal tissue. At diagnosis, other diseases that can be associated with oesophageal eosinophilic infiltration must be ruled out. Children with EoE present with a wide variety of symptoms, whereas adults mostly present with dysphagia for solid food and chest pain. Histologic features of EoE resemble those of T-helper type 2 inflammation. Endoscopy should be carried out to establish the diagnosis, but endoscopic abnormalities are not pathognomonic for EoE and the examination might not show histologic abnormality. Treatment modalities for EoE include drugs (corticosteroids, PPIs, antiallergic and biologic agents), hypoallergenic diets and oesophageal dilatation for strictures that are unresponsive to medical therapy. Unresolved eosinophilic inflammation leads to the formation of oesophageal strictures, which probably increase the risk of food bolus impactions. To date, long-term strategies for the therapeutic management of this chronic inflammatory disease remain poorly defined.

Predicting and establishing the clinical efficacy of a histamine h(1)-receptor antagonist : desloratadine, the model paradigm

Antihistamines are well established as a mainstay for treating allergic diseases, including seasonal and perennial allergic rhinitis as well as other conditions, such as chronic idiopathic urticaria. The development of new antihistamines is a multistage process that includes in vitro and in vivo assessments of the antihistaminic, anti-inflammatory and antiallergic properties of new therapies. Results of these assessments are critical for predicting and establishing the clinical efficacy of an antihistamine. The focus of this article is to review the investigational methods used to assess the efficacy, safety and tolerability of newer histamine H(1)-receptor antagonists. Desloratadine, a new-generation H(1)-receptor antagonist, was chosen to illustrate the use of this model paradigm. Data obtained from two large observational studies are presented, confirming results obtained from clinical trials that the in vitro inhibition of release of inflammatory mediators such as histamine, prostaglandins, leukotrienes and the reduction of secretion of cytokines such as IL-4 and IL-13 at physiological concentrations is reflected in increased efficacy, particularly upon nasal obstruction. A recent discovery that des- loratadine inhibits nuclear factor-kappaB may be the underlying explanation for much of this extra anti-inflammatory activity.

Pathogenesis and classification of eosinophil disorders: a review of recent developments in the field

Eosinophils and their products play an essential role in the pathogenesis of various reactive and neoplastic disorders. Depending on the underlying disease, molecular defect and involved cytokines, hypereosinophilia may develop and may lead to organ damage. In other patients, persistent eosinophilia is accompanied by typical clinical findings, but the causative role and impact of eosinophilia remain uncertain. For patients with eosinophil-mediated organ pathology, early therapeutic intervention with agents reducing eosinophil counts can be effective in limiting or preventing irreversible organ damage. Therefore, it is important to approach eosinophil disorders and related syndromes early by using established criteria, to perform all appropriate staging investigations, and to search for molecular targets of therapy. In this article, we review current concepts in the pathogenesis and evolution of eosinophilia and eosinophil-related organ damage in neoplastic and non-neoplastic conditions. In addition, we discuss classifications of eosinophil disorders and related syndromes as well as diagnostic algorithms and standard treatment for various eosinophil-related disorders.

IFN-γ-inducible protein of 10 kDa upregulates the effector functions of eosinophils through β2 integrin and CXCR3

BACKGROUND

Eosinophils play an important role in the pathogenesis of bronchial asthma and its exacerbation. Recent reports suggest the involvement of IFN-γ-inducible protein of 10 kDa (IP-10) in virus-induced asthma exacerbation. The objective of this study was to examine whether CXCR3 ligands including IP-10 modify the effector functions of eosinophils.

METHODS

Eosinophils isolated from the blood of healthy donors were stimulated with CXCR3 ligands and their adhesion to rh-ICAM-1 was then measured using eosinophil peroxidase assays. The generation of eosinophil superoxide anion (O2-) was examined based on the superoxide dismutase-inhibitable reduction of cytochrome C. Eosinophil-derived neurotoxin (EDN) release was evaluated to determine whether CXCR3 ligands induced eosinophil degranulation. Cytokine and chemokine production by eosinophils was examined using a Bio-plex assay.

RESULTS

Eosinophil adhesion to ICAM-1 was significantly enhanced by IP-10, which also significantly induced eosinophil O2- generation in the presence of ICAM-1. Both the enhanced adhesion and O2- generation were inhibited by an anti-β2 integrin mAb or an anti-CXCR3 mAb. Other CXCR3 ligands, such as monokine induced by IFN-γ (Mig) and IFN-inducible T cell α chemoattractant (I-TAC), also induced eosinophil adhesion and O2- generation in the presence of ICAM-1. IP-10, but not Mig or I-TAC, increased the release of EDN. IP-10 increased the production of a number of cytokines and chemokines by eosinophils.

CONCLUSIONS

These findings suggest that CXCR3 ligands such as IP-10 can directly upregulate the effector functions of eosinophils. These effects might be involved in the activation and infiltration of eosinophils in the airway of asthma, especially in virus-induced asthma exacerbation.

Regulator of calcineurin 1 (Rcan1) is required for the development of pulmonary eosinophilia in allergic inflammation in mice

The presence of eosinophils in the lung is often regarded as a defining feature of asthma. On allergen stimulation, numbers of eosinophils and their progenitors are increased in both the bone marrow and lungs. Eosinophil progenitors provide an ongoing supply of mature eosinophils. Here, we report that deficiency in the regulator of calcineurin 1 gene (Rcan1) leads to a near-complete absence of eosinophilia in ovalbumin-induced allergic asthma in mice. In the absence of Rcan1, bone marrow cells produce significantly fewer eosinophils in vivo and in vitro on interleukin-5 stimulation. Importantly, eosinophil progenitor populations are significantly reduced in both naïve and ovalbumin-challenged Rcan1(-/-) mice. Bone marrow cells from Rcan1(-/-) mice are capable of developing into fully mature eosinophils, suggesting that Rcan1 is required for eosinophil progenitor production but may not be necessary for eosinophil maturation. Thus, Rcan1 represents a novel contributor in the development of eosinophilia in allergic asthma through regulation of eosinophil progenitor production.

A peptide binding to dimerized translationally controlled tumor protein modulates allergic reactions

Translationally controlled tumor protein (TCTP) is believed to be involved in a variety of inflammatory processes: secretion of histamine and cytokines such as IL-4, IL-8, IL-13, and granulocyte/macrophage colony-stimulating factor; chemoattraction for eosinophils; augmentation of B cell proliferation; and immunoglobulin production, thereby potentially regulating allergic phenomena. In a previous study, we showed that the cytokine-releasing activity of extracellular TCTP is generated only when TCTP dimerizes via the intermolecular disulfide bond of NH(2)-terminal truncated TCTP implying that the dimerized TCTP (dTCTP) promotes the inflammatory phenomena. Modulation of dTCTP, thus, may offer a strategy for the treatment of chronic allergic diseases. In this study, we searched for dTCTP-binding peptides (dTBPs) by screening a phage-displayed 7-mer peptide library. We identified one peptide in the library, designated as dTBP2, which showed higher affinity to dTCTP than to full-length, monomeric TCTP. dTBP2 inhibited the induction of IL-8 by dTCTP from BEAS-2B cells. dTBP2 also reduced symptom score and eosinophil infiltration in a mouse rhinitis model. This study suggests that the dTBP2 binding to dTCTP modulates the release of inflammatory mediators of dTCTP. This result may provide a rational strategy for the treatment of allergic diseases.

BN.MES-Cyba(mes) congenic rats manifest focal necrosis with eosinophilic infiltration in the liver without blood eosinophilia

The Matsumoto Eosinophilia Shinshu (MES) rat strain develops hereditary blood eosinophilia and eosinophil-related inflammatory lesions in organs due to the mutant Cyba(mes) gene. We hypothesized that a new eosinophilia model with a different phenotype could be established by changing the genetic background of rats. We bred and characterized a congenic strain, in which the mutant Cyba(mes) gene was introduced into the background of a BN strain (BN.MES-Cyba(mes)). The congenic rats showed robust proliferation of eosinophils in the bone marrow. Nonetheless, blood eosinophil levels of the rats remained within the normal range. In addition, the rats manifested focal necrosis with eosinophilic infiltration in the liver, a phenotype rarely observed in the original MES rat strain. These results imply the presence of genetic polymorphisms between MES and BN strains which modulate the mobilization of eosinophils to the peripheral circulation and organs. The newly established BN.MES-Cyba(mes) congenic rat strain, together with the original MES strain, will provide useful models for elucidating the molecular genetic mechanisms involved in the development and trafficking of eosinophils.

Homoisoflavonoid derivatives from the roots of Ophiopogon japonicus and their in vitro anti-inflammation activity

Three new homoisoflavonoids (1-3) were isolated from the roots of Ophiopogon japonicus (Liliaceae). The structures of new metabolites were determined on the basis of spectroscopic analyses including 2D NMR. The anti-inflammatory activities of new compounds (1-3) were investigated by their effects on the release of the inflammatory chemokine eotaxin, stimulated by IL-4 and the combination of IL-4 and TNF-alpha in BEAS-2B cells, which mimics the in vivo conditions in bronchial allergic asthma.

Dammarane-type glycosides from Gynostemma pentaphyllum and their effects on IL-4-induced eotaxin expression in human bronchial epithelial cells

Two new dammarane-type glycosides, 2alpha,3beta,12beta,20S-tetrahydroxydammar-24-ene-3-O-[beta-d-glucopyranosyl(1-->4)-beta-d-glucopyranosyl]-20-O-[beta-d-xylopyranosyl-(1-->6)-beta-d-glucopyranoside] (1) and 2alpha,3beta,12beta,20S-tetrahydroxydammar-24-ene-3-O-beta-d-glucopyranosyl-20-O-[beta-d-6-O-acetylglucopyranosyl-(1-->2)-beta-d-glucopyranoside] (2), were isolated from a MeOH extract of the leaves of Gynostemma pentaphyllum. Their structures were elucidated by 1D and 2D NMR spectroscopic interpretation as well as by chemical studies. The isolated compounds showed potential inhibitory effects on eotaxin expression in BEAS-2B bronchial epithelial cells.

Aberrant inflammatory response to Streptococcus pyogenes in mice lacking myeloid differentiation factor 88

Several in vitro studies have emphasized the importance of toll-like receptor/myeloid differentiation factor 88 (MyD88) signaling in the inflammatory response to Streptococcus pyogenes. Since the extent of inflammation has been implicated in the severity of streptococcal diseases, we have examined here the role of toll-like receptor/MyD88 signaling in the pathophysiology of experimental S. pyogenes infection. To this end, we compared the response of MyD88-knockout (MyD88(-/-)) after subcutaneous inoculation with S. pyogenes with that of C57BL/6 mice. Our results show that MyD88(-/-) mice harbored significantly more bacteria in the organs and succumbed to infection much earlier than C57BL/6 animals. Absence of MyD88 resulted in diminished production of inflammatory cytokines such as interleukin-12, interferon-gamma, and tumor necrosis factor-alpha as well as chemoattractants such as monocyte chemotactic protein-1 (MCP-1) and Keratinocyte-derived chemokine (KC), and hampered recruitment of effector cells involved in bacterial clearance (macrophages and neutrophils) to the infection site. Furthermore, MyD88(-/-) but not C57BL/6 mice exhibited a massive infiltration of eosinophils in infected organs, which can be explained by an impaired production of the regulatory chemokines, gamma interferon-induced monokine (MIG/CXCL9) and interferon-induced protein 10 (IP-10/CXCL10), which can inhibit transmigration of eosinophils. Our results indicate that MyD88 signaling targets effector cells to the site of streptococcal infection and prevents extravasation of cells that can induce tissue damage. Therefore, MyD88 signaling may be important for shaping the quality of the inflammatory response elicited during infection to ensure optimal effector functions.

A new compound, 1H,8H-pyrano[3,4-c]pyran-1,8-dione, suppresses airway epithelial cell inflammatory responses in a murine model of asthma

Clinical and experimental studies have established eosinophilia as a sign of allergic disorders. Activation of eosinophils in the airways is believed to cause epithelial tissue injury, contraction of airway smooth muscle and increased bronchial responsiveness. As part of the search for new antiasthmatic agents produced by medicinal plants, the effects of 270 standardized medicinal plant extracts on cytokine-activated A549 human lung epithelial cells were evaluated. After several rounds of activity-guided screening, the new natural compound, 1H,8H-Pyrano[3,4-c]pyran-1,8-dione (PPY), was isolated from Vitex rotundifolia L. To elucidate the mechanism by which the anti-asthmatic responses of PPY occurred in vitro, lung epithelial cells (A549 cell) were stimulated with TNF-alpha, IL-4 and IL-1beta to induce the expression of chemokines and adhesion molecules involved in eosinophil chemotaxis. PPY treatments reduced the expression of eotaxin, IL-8, IL-16 and VCAM-1 mRNA significantly. Additionally, PPY reduced eotaxin secretion in a dose-dependent manner and significantly inhibited eosinophil migration toward A549 medium. In addition, PPY treatment suppressed the phosphorylation of p65 and ERK1/2, suggesting that it can inhibit the MAPK/NF-KB pathway. To clarify the anti-inflammatory and antiasthmatic effects of PPY in vivo, we examined the influence of PPY on the development of pulmonary eosinophilic inflammation in a murine model of asthma. To accomplish this, mice were sensitized and challenged with ovalbumin (OVA) and then examined for the following typical asthmatic reactions: an increase in the number of eosinophils in BALF; the presence of Th2 cytokines such as IL-4 and IL-5 in the BALF; the presence of allergen-specific IgE in the serum; and a marked influx of inflammatory cells into the lung. Taken together, our results revealed that PPY exerts profound inhibitory effects on the accumulation of eosinophils into the airways while reducing the levels of IL-4, IL-5, and IL-13 in the BALF. Therefore, these results suggest that PPY may be useful as a new therapeutic drug for the treatment of allergic asthma.

Eosinophilic gastroenteritis: a review

Eosinophilic gastroenteritis is a clinicopathological disease affecting both children and adults that is characterized by patchy or diffuse eosinophilic infiltration of the gastrointestinal tract with variable resultant clinical gastrointestinal manifestations. The eosinophil, eotaxin, and Th-2 cytokines are important in pathogenesis of this disease entity. It may be confused with parasitic and bacterial infections (including Helicobacter pylori), inflammatory bowel disease, hypereosinophilic syndrome, myeloproliferative disorders, periarteritis, allergic vasculitis, scleroderma, drug injury, and drug hypersensivity. Obtaining the correct diagnosis is important, and a pathologist usually makes this distinction. Effective treatments include systemic/topical corticosteroids, specific food elimination or an elemental diet, certain drugs, and even surgery. A variety of new therapeutic approaches are now under trial.

Biology of the eosinophil

In this review, we aim to put in perspective the biology of a multifunctional leukocyte, the eosinophil, by placing it in the context of innate and adaptive immune responses. Eosinophils have a unique contribution in initiating inflammatory and adaptive responses, due to their bidirectional interactions with dendritic cells and T cells, as well as their large panel of secreted cytokines and soluble mediators. The mechanisms and consequences of eosinophil responses in experimental inflammatory models and human diseases are discussed.

Intestinal macrophage/epithelial cell-derived CCL11/eotaxin-1 mediates eosinophil recruitment and function in pediatric ulcerative colitis

Clinical studies have demonstrated a link between the eosinophil-selective chemokines, eotaxins (eotaxin-1/CCL11 and eotaxin-2/CCL24), eosinophils, and the inflammatory bowel diseases, Crohn's disease and ulcerative colitis (UC). However, the cellular source and individual contribution of the eotaxins to colonic eosinophilic accumulation in inflammatory bowel diseases remain unclear. In this study we demonstrate, by gene array and quantitative PCR, elevated levels of eotaxin-1 mRNA in the rectosigmoid colon of pediatric UC patients. We show that elevated levels of eotaxin-1 mRNA positively correlated with rectosigmoid eosinophil numbers. Further, colonic eosinophils appeared to be degranulating, and the levels positively correlated with disease severity. Using the dextran sodium sulfate (DSS)-induced intestinal epithelial injury model, we show that DSS treatment of mice strongly induced colonic eotaxin-1 and eotaxin-2 expression and eosinophil levels. Analysis of eosinophil-deficient mice defined an effector role for eosinophils in disease pathology. DSS treatment of eotaxin-2(-/-) and eotaxin-1/2(-/-) mice demonstrated that eosinophil recruitment was dependent on eotaxin-1. In situ and immunofluorescence analysis-identified eotaxin-1 expression was restricted to intestinal F4/80(+)CD11b(+) macrophages in DSS-induced epithelial injury and to CD68(+) intestinal macrophages and the basolateral compartment of intestinal epithelial cells in pediatric UC. These data demonstrate that intestinal macrophage and epithelial cell-derived eotaxin-1 plays a critical role in the regulation of eosinophil recruitment in colonic eosinophilic disease such as pediatric UC and provides a basis for targeting the eosinophil/eotaxin-1 axis in UC.

Eosinophil progenitors in allergy and asthma - do they matter?

Allergic inflammation is associated with marked infiltration of eosinophils in affected tissues. The eosinophil is believed to be a key effector cells in allergen induced asthma pathogenesis. However, the role of eosinophils in the clinical manifestation of asthma has recently been questioned, since therapies directed against eosinophil infiltration (i.e. anti-interleukin-5) failed to improve clinical symptoms such as airways hyper-responsiveness (AHR) in patients with asthma. Although eosinophils in peripheral blood and the airways were largely depleted after anti-IL-5 treatment, residual eosinophilia in lung tissue persisted, which permits speculation that the remaining eosinophils may be sufficient to drive the asthma symptomatology. Furthermore, recent findings suggest that primitive eosinophil progenitor cells traffic from the bone marrow to sites of inflammation in response to allergen exposure. These progenitors may then differentiate in situ and thus provide an ongoing supply of mature pro-inflammatory cells and secretory mediators that augment the inflammatory response. In the present article, we will review the evidence for these findings, and discuss the rationale for targeting hematopoiesis and their migration pathways in the treatment of allergic diseases. Furthermore, this review will highlight the hypothesis that both IL-5- and CCR3-mediated signaling pathways may need to be targeted in order to control the inflammation and AHR associated with asthma.

Adjuvant Activity of Ambient Particulate Matter in Macrophage Activity-Suppressed,N-Acetylcysteine-Treated, iNOS- and IL-4-Deficient Mice

In previous studies, we have shown strong adjuvant activity for Ottawa dust (EHC-93) after coexposure of the BALB/c mouse to EHC-93 and ovalbumin. Mice were intranasally sensitized at days 0 and 14 with 200 microg ovalbumin and 150 microg EHC-93, and challenged with ovalbumin at days 35, 38, and 41 with 200 microg ovalbumin. Mice were autopsied at day 42. This adjuvant activity was shown for the antibody response to ovalbumin (immunoglobulins E, G1, and G2a), histopathological lesions in the lung, cytokines, and the numbers of eosinophils in lung lavages. To study the mechanisms of this adjuvant activity, mice (BALB/cC.D2-Vil6) with natural-resistance-associated macrophage protein (Nramp1s), BALB/c mice pretreated with the antioxidant N-acetylcysteine (NAC), mice (B6.129P2-Nos2tmLau) deficient in inducible nitric oxide synthase (iNOS), and mice with interleukin-4 (IL-4) deficiency (BALB/cIl4< tm2Nnt) were coexposed to ovalbumin and EHC-93. Our studies have shown that the adjuvant activity induced after such coexposure does not change if the macrophage activation of the mice is disturbed or if the mice have been pretreated with N-acetylcysteine. In addition, the adjuvant activity does not develop through the pathway in which inducible nitric oxide synthase is involved. Because the histopathological lesions are statistically significant less in the IL-4 knockout strain in comparison with the wild type, we conclude that interleukin-4 might play an important role in the adjuvant activity caused by EHC-93.

Indices of lower airway inflammation in children monosensitized to house dust mite after nasal allergen challenge

BACKGROUND

There are few available data assessing the united airway disease and its systemic aspects in children. With this study, we aimed to investigate the inflammation markers of upper and lower airways before and after nasal allergen challenge in mite sensitive children with different clinical expression of the allergic disease.

METHODS

Four study groups were formed: rhinitis only, without bronchial hyper-responsiveness (R, n = 10), rhinitis with asthma (R + A, n = 22), atopic asymptomatics (AA, n = 8) and nonallergic healthy controls (C, n = 10). Blood eosinophils, nasal and sputum eosinophils, sputum eosinophil cationic protein (ECP) and cys-LTs, and serum ECP levels were measured before and 24 h after nasal allergen challenge.

RESULTS

The groups were comparable in terms of age and gender. Cumulative symptom scores recorded during and 1 h after nasal challenge were not significantly different between patients with R, R + A and AA groups. At T(24), the children belonging to R, R + A and AA showed significant increases in nasal eosinophils (P < 0.01, P < 0.001, and P = 0.01, respectively), sputum eosinophils (P = 0.01, P < 0.001, and P < 0.05, respectively) and blood eosinophils (P < 0.01, P < 0.001, and P < 0.05, respectively). Similarly, increases in sputum ECP (P < 0.01, P < 0.001, and P = 0.07, respectively) and sputum cys-LT levels (P = 0.07, P < 0.001, and P < 0.05, respectively) were detected in children belonging to these three groups at T(24). Sputum eosinophils significantly correlated with blood eosinophils (r = 0.54, P < 0.001) and sputum ECP (r = 0.58, P < 0.001) at T(24).

CONCLUSIONS

This study showed that nasal allergen challenge increased markers of eosinophilic inflammation in both upper and lower airways of children monosensitized to mites, even before the onset of clinical symptoms.

Effect of the Chinese herb extract osthol on IL-4-induced eotaxin expression in BEAS-2B cells

BACKGROUND

Asthma is an allergic inflammatory disease of the airways. The interaction between bronchial epithelial cells and eosinophils is an important feature of an asthma attack. Eotaxin, an eosinophil-specific C-C chemokine, is a potent chemoattractant involved in the mobilization of eosinophils into the airway after allergic stimulation. Cnidii monnieri fructus, the dried fruit of Cnidium monnieri Cusson, has been used as an antipruritogenic agent in ancient China. OsthoL is the major component of Cnidii monnieri fructus extract. We investigated the ability of osthol to regulate cytokine-induced eotaxin expression in the human bronchial epithelial cell line BEAS-2B.

METHODS

BEAS-2B cells were pretreated with osthol at different concentrations (0.1-10 microM), and then stimulated with interleukin (IL)-4 alone, or in combination with tumor necrosis factor (TNF)-alpha. Eotaxin levels were determined by real-time reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. STAT6 (signal transducer and activator of transcription 6) and MAPK (mitogen-activated protein kinase) expressions were evaluated by Western blotting, to detect possible intracellular signal transduction.

RESULTS

IL-4 and TNF-alpha significantly induced eotaxin expression in BEAS-2B cells. Expression of eotaxin was suppressed by osthol (0.1-10 microM) in a dose-dependent manner. Osthol did not suppress IL-4-induced p38, ERK or JNK expression. Osthol did suppress IL-4-induced STAT6 in a dose-dependent manner.

CONCLUSION

Osthol suppressed IL-4-induced eotaxin in BEAS-2B cells via inhibition of STAT6 expression. This data suggest that osthol might have potential for treating allergic airway inflammation.

Eosinophils: biological properties and role in health and disease

Eosinophils are pleiotropic multifunctional leukocytes involved in initiation and propagation of diverse inflammatory responses, as well as modulators of innate and adaptive immunity. In this review, the biology of eosinophils is summarized, focusing on transcriptional regulation of eosinophil differentiation, characterization of the growing properties of eosinophil granule proteins, surface proteins and pleiotropic mediators, and molecular mechanisms of eosinophil degranulation. New views on the role of eosinophils in homeostatic function are examined, including developmental biology and innate and adaptive immunity (as well as their interaction with mast cells and T cells) and their proposed role in disease processes including infections, asthma, and gastrointestinal disorders. Finally, strategies for targeted therapeutic intervention in eosinophil-mediated mucosal diseases are conceptualized.

Genetic susceptibility to atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disorder with an increasing prevalence in industrialized countries. AD belongs to the group of allergic disorders that includes food allergy, allergic rhinitis, and asthma. A multifactorial background for AD has been suggested, with genetic as well as environmental factors influencing disease development. Recent breakthroughs in genetic methodology have greatly augmented our understanding of the contribution of genetics to susceptibility to AD. A candidate gene association study is a general approach to identify susceptibility genes. Fifty three candidate gene studies (50 genes) have identified 19 genes associated with AD risk in at least one study. Significant associations between single nucleotide polymorphisms (SNPs) in chemokines (chymase 1-1903A > G), cytokines (interleukin13 Arg144Gln), cytokine receptors (interleukin 4 receptor 1727G > A) and SPINK 1258G > A have been replicated in more than one studies. These SNPs may be promising for identifying at-risk individuals. SNPs, even those not strongly associated with AD, should be considered potentially important because AD is a common disease. Even a small increase in risk can translate to a large number of AD cases. Consortia and international collaborative studies, which may maximize study efficacy and overcome the limitations of individual studies, are needed to help further illuminate the complex landscape of AD risk and genetic variations.

Fritillaria cirrhosa, Anemarrhena asphodeloides, Lee-Mo-Tang and cyclosporine a inhibit ovalbumin-induced eosinophil accumulation and Th2-mediated bronchial hyperresponsiveness in a murine model of asthma

Asthma is a chronic inflammatory disorder of the airways characterized by excess production of Th2 cytokines and eosinophil accumulation in the lungs. Fritillaria cirrhosa, Anemarrhena asphodeloides and Lee-Mo-Tang are well-known herbs used in oriental medicine for the treatment of asthma and bronchial inflammation. To clarify the anti-asthmatic effects of Fritillaria cirrhosa bulbus, Anemarrhena rhizoma and Lee-Mo-Tang, we examined the development of pulmonary eosinophilic accumulation, control of Th2 cytokine, immunoglobulin E (IgE) and histamine productions in a murine model of asthma. Eosinophil cell proliferation was performed by [(3)H]thymidine uptake, eosinophilic accumulation. Cell counts in bronchoalveolar lavage fluid were investigated by means of fluorescence activated cell sorter analysis and control of Th2 cytokine, IgE and histamine productions were investigated by RT-PCR and ELISA. Moreover, lung tissue was histologically analysed. The suppressive effects of Fritillaria cirrhosa bulbus, Anemarrhena rhizoma and Lee-Mo-Tang on eosinophil recruitment and airway inflammation were demonstrated throughout the reduction of eosinophil numbers. This result correlated with a marked reduction IL-5, IL-13 and IL-4 levels in the bronchoalveolar lavage fluid. Ovalbumin-specific IgE levels were also decreased in serum. Fritillaria cirrhosa bulbus, Anemarrhena rhizoma and Lee-Mo-Tang have deep inhibitory effects on airway inflammation by suppression of Th2 cytokines (IL-4, IL-5 and IL-13), IgE, histamine production, reduction eosinophilic accumulation and increase of interferon-gamma production.

Recent advances in eosinophil biology

Eosinophils are pleiotropic multi-functional leukocytes involved in initiation and propagation of diverse inflammatory responses. Recent studies examining eosinophil biology have focused on delineating the molecular basis of FIP1L1/PDGRFalpha-fusion gene induced HES, the molecular steps involved in eosinophil recruitment in tumor-associated eosinophilia and EGID, and the role of eosinophils in asthma. In this review, these studies are summarized, focusing on the implications of these findings in the understanding the role of eosinophils in diseases.

Effect of interleukin-13 or tumor necrosis factor-alpha on eosinophil adhesion to endothelial cells under physiological flow conditions

RATIONALE

We examined the mechanisms used by eosinophils to accumulate on IL-13- or TNF-alpha-stimulated human umbilical vein endothelial cells (HUVECs) under flow conditions.

METHODS

HUVECs were treated for 1, 3, 6, 18 and 24 h with IL-13 or TNF-alpha (1-100 ng/ml). Human eosinophils were infused at physiologic flow rates (0.5 dyn/cm(2)) for 10 min, and attached eosinophils were counted.

RESULTS

Under these flow conditions, eosinophils accumulated efficiently on IL-13-stimulated (109 +/- 18 cells/field) or TNF-alpha-stimulated (96 +/- 27 cells/field) HUVECs in a concentration-dependent manner. Eosinophil accumulation on IL-13-activated HUVECs was first observed at 3 h and reached a maximum at 24 h. On the other hand, the levels of eosinophils accumulating on TNF-alpha-activated HUVECs were the same at all time points (1, 3, 6, 18 and 24 h). Anti-alpha4 integrin mAb inhibited eosinophil accumulation on both IL-13- and TNF-alpha-activated HUVECs.

CONCLUSIONS

Eosinophil accumulation on HUVECs under physiologic flow conditions is differentially regulated by IL-13 and TNF-alpha.

High expression of co-stimulatory and adhesion molecules are observed on eosinophils during human Schistosoma mansoni infection

Herein we have focused attention on major phenotypic features of peripheral blood eosinophils from chronic Schistosoma mansoni-infected patients. For this purpose, detailed immunophenotypic profiles of a range of cell surface markers were performed, including activation markers (CD23/CD69/CD25/HLA-DR), co-stimulatory molecules (CD28/CD80/CD86), chemokine receptors (CXCR1/CXCR2/CCR3/CCR5) besides L-selectin-CD62L and adhesion molecules (CD18/CD54). Our major findings pointed out increased frequency of CD23+-cells, besides decreased percentages of CD69+-eosinophils, suggesting a chronic activation status with low frequency of early activated eosinophils in chronic S. mansoni-infected patients (INT) in comparison to non-infected individuals (NI). Moreover, a dichotomic expression of beta-chemokine receptors was observed during human schistosomiasis mansoni with higher CCR5 and lower levels of CCR3 observed between groups. Enhanced expression of co-stimulatory receptors (CD28/CD86) and adhesion molecules (CD54/CD18), besides striking lower frequency of L-selectin+ were reported for eosinophils from INT group as compared to NI. Interestingly, the frequency of CD62L+-eosinophils and a range of cell activation related molecules pointed out an opposite pattern of association in NI and INT, where only INT patients that display lower frequency of CD62L+-eosinophils (first CD62L tertile) kept the unusual relationship between the expression of L-selectin and the CD23 activation marker. These findings suggest that distinct dynamic of activation markers expressed by eosinophils may occur during chronic S. mansoni infection.

Induction of adhesion molecules upon the interaction between eosinophils and bronchial epithelial cells: involvement of p38 MAPK and NF-kappaB

Eosinophils are principal effector cells of inflammation in allergic asthma, characterized by their infiltration and accumulation at inflammatory sites mediated by chemokine eotaxin, and interaction with adhesion molecules expressed on bronchial epithelial cells. In this study, tumor necrosis factor (TNF)-alpha and/or the interaction of eosinophils and bronchial epithelial BEAS-2B cells were found to up-regulate the cell surface expression of adhesion molecules intercellular adhesion molecule (ICAM)-1 and vascular adhesion molecule (VCAM)-1 on BEAS-2B cells, and ICAM-1 and leukocyte function-associated antigen-1 (LFA-1) on eosinophils. Interaction of eosinophils and BEAS-2B cells could induce the release of granulocyte macrophage colony-stimulating factor (GM-CSF) and activate both p38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-kappaB activities in BEAS-2B cells but only NF-kappaB activity in eosinophils. Both proteasome inhibitor MG-132 and selective p38 MAPK inhibitor SB 203580 could significantly decrease the expression of ICAM-1 on BEAS-2B cells and CD18 on eosinophils upon co-culture with or without TNF-alpha treatment. However, the expression of VCAM-1 on BEAS-2B cells was only up-regulated by TNF-alpha-induced NF-kappaB activity. The interaction of eosinophils and bronchial epithelial cells therefore plays an important role in the up-regulation of adhesion molecules on eosinophils and epithelial cells via differential intracellular signalling pathways during allergic inflammation.

Mooren Ulcer

PURPOSE

To determine the pattern and distribution of mononuclear cells, adhesion, and co-stimulatory molecules in the conjunctiva of patients with Mooren ulcer.

METHODS

Conjunctival biopsy specimens were obtained from 6 patients with Mooren ulcer and 6 healthy individuals. Immunohistochemistry was performed on frozen sections of the cryopreserved human conjunctivas using monoclonal antibodies directed against CD1alpha, CD3, CD4, CD8, CD20, CD25, CD57, and CD68 cells; the adhesion molecules E-selectin, vascular cell adhesion molecule-1 (VCAM-1), very late activation-4 (VLA-4), ICAM-1, and LFA-1; and the co-stimulatory molecules CD28, B7-1, B7-2, and CTLA-4.

RESULTS

Differences in expression on the conjunctival epithelium from patients with Mooren ulcer and normal subjects were noted only for VCAM-1, VLA-4, ICAM-1, and LFA-1. The ratio of CD4+/CD8+ cells in Mooren ulcer specimens was significantly higher (3.5-fold). However, in the substantia propria, Mooren ulcer specimens revealed significantly increased numbers of CD1alpha+, CD3+, CD4+, CD20+, CD28+, B7-1+, B7-2+, and CD68+ cells. The ratios of CD4+/CD8+ cells and B7-2+/antigen-presenting cells in Mooren ulcer specimens were significantly higher (5-fold). All tested adhesion molecules showed significant up-regulation in the patients' conjunctivas. Mooren ulcer vascular endothelial cells prominently expressed E-selectin, VCAM-1, VLA-4, and ICAM-1 compared with normal conjunctiva.

CONCLUSION

The simultaneous presence of multiple types of inflammatory cells, adhesion, and co-stimulatory molecules in Mooren ulcer conjunctiva suggests that their interaction may contribute to a sustained immune activation as at least part of the pathogenic mechanism of this disorder.