Eosinophils: biological properties and role in health and disease

Eosinopenia as a marker of diagnosis and prognostic to distinguish bacterial from aseptic meningitis in pediatrics

Procalcitonin (PCT) has proven its efficacy to distinguish bacterial from aseptic meningitis in children. Nevertheless, its use in routine is limited by its cost and availability, especially in low- and middle-income countries. It is now acknowledged that eosinopenia is a marker of infection and/or severity of the systemic inflammatory response. Although no study ever demonstrated that eosinopenia could differentiate bacterial from viral infection, we decided to conduct a study concerning meningitis in children. This bicentric and retrospective study was conducted between January 2012 and October 2018, in children hospitalized for meningitis. The white blood cell was systematically gathered at the admission to evaluate the eosinophil count. Characteristic data were compared between 2 groups: documented bacterial meningitis (DBP) and aseptic meningitis which includes documented viral meningitis (DVM) and non-documented meningitis (ND). Among 190 patients admitted for meningitis, 151 were analyzed, including DBM (n = 45), DVM (n = 73), and ND (n = 33) meningitis. Groups were comparable. Mean age was 33 ± 48 months with a sex ratio of 1.6. Mean of eosinophil count was 15 ± 34/mm³ in the DBM group versus 132 ± 167/mm³ for the aseptic meningitis group (p < 0.0001). Best threshold for the diagnosis of bacterial meningitis was an eosinophil count < 5/mm³ with a sensitivity of 80% and specificity of 73% and a likelihood ratio of 2.9. Eosinopenia seems to be a reliable and non-invasive marker of bacterial meningitis in pediatrics. The absence of extra cost makes it very interesting in low- and middle-income countries or when usual biomarkers such as PCT are unavailable.

Eosinophils count in peripheral circulation is associated with coronary artery disease

BACKGROUND AND AIMS

Allergic asthma can accelerate atherosclerosis, a disease in which plaque is deposited onto arterial walls and that may lead to coronary artery disease (CAD). Eosinophils are the most important effector cells in allergic asthma and are likely to become novel biomarkers for risk stratification of patients with CAD, but the relationship between eosinophil count and CAD remains unclear. We aimed to evaluate this relationship and the use of eosinophils in predicting CAD.

METHODS

A total of 5287 patients who underwent coronary angiography were recruited. Their biochemical parameters, including eosinophil count, were measured and their correlation with the severity of coronary artery stenosis, as quantified by the Gensini score system, was evaluated.

RESULTS

The percentages of eosinophils in leukocytes (PELs) were lower in CAD patients (p < 0.001), and had a significant negative correlation with Gensini scores (r = -0.112, p < 0.001). PELs were also significantly lower in acute myocardial infarction patients (p < 0.001). After adjusting for baseline differences, low PELs remained strongly associated with severe CAD and acute coronary arterial thrombotic event. Receiver-operating characteristic curve analysis showed that combining PELs with traditional risk factors in predictive models for CAD severity (z = 4.470, p < 0.001) or acute coronary arterial thrombotic event (z = 9.435, p < 0.001) improved the predictive capabilities of those models.

CONCLUSIONS

PELs, at least in patients undergoing coronary angiography, may be strongly related to the subtype and severity of CAD and, therefore, eosinophil count may be an accurate and independent biomarker to predict CAD severity and acute coronary arterial thrombotic events.

White blood cell count and eosinopenia as valuable tools for the diagnosis of bacterial infections in the ED

Identifying an infection may be difficult in the ED. Neutrophilic leukocytosis is often used in the diagnosis of infection despite its lack of specificity in situations of stress. Our objective was to study the value of each parameter of the WBC count, in particular eosinopenia, to diagnose bacterial infections in the ED. We conducted a retrospective and observational study over a period of 6 months. All patients with one of the following diagnoses were eligible: pneumonia (9.9%), pyelonephritis (26.2%), prostatitis (8.4%), appendicitis (26.2%), cholecystitis (8.4%), and diverticular sigmoiditis (5%). A total of 466 infected patients were included for statistical analysis, and a control group of 466 uninfected patients was randomly selected in the same period of time. All leukocyte count parameters were significantly modified (p < 0.001) in the infected group compared with the control group. Neutrophils and total leukocytes remain the two most suitable parameters for the diagnosis of infections in the ED. Eosinopenia represented the most efficient parameter of the WBC count for the diagnosis of urinary and biliary tract infections. Deep eosinopenia presented a specificity of 94% for the diagnosis of infection. Any modification of the WBC count associated with an elevation of CRP (> 40 mg/L) or fever (> 38.5 °C) showed a high specificity for the diagnosis of infection. A careful analysis of the WBC count remains a valuable tool for the diagnosis of infection in the ED.

Butyrate ameliorates allergic airway inflammation by limiting eosinophil trafficking and survival

BACKGROUND

Lung eosinophilia is a hallmark of asthma, and eosinophils are believed to play a crucial role in the pathogenesis of allergic inflammatory diseases. Short-chain fatty acids (SCFAs), such as acetate, propionate, and butyrate, are produced in high amounts in the gastrointestinal tract by commensal bacteria and can be absorbed into the bloodstream. Although there is recent evidence that SCFAs are beneficial in allergic asthma models, the effect on eosinophils has remained elusive.

OBJECTIVE

The role of SCFAs was investigated in human eosinophil function and a mouse model of allergic asthma.

METHODS

Eosinophils were purified from self-reported allergic or healthy donors. Migration, adhesion to the endothelium, and eosinophil survival were studied in vitro. Ca²⁺ flux, apoptosis, mitochondrial membrane potential, and expression of surface markers were determined by using flow cytometry and in part by using real-time PCR. Allergic airway inflammation was assessed in vivo in an ovalbumin-induced asthma model by using invasive spirometry.

RESULTS

For the first time, we observed that SCFAs were able to attenuate human eosinophils at several functional levels, including (1) adhesion to the endothelium, (2) migration, and (3) survival. These effects were independent from GPR41 and GPR43 but were accompanied by histone acetylation and mimicked by trichostatin A, a pan-histone deacetylase inhibitor. In vivo butyrate ameliorated allergen-induced airway and lung eosinophilia, reduced type 2 cytokine levels in bronchial fluid, and improved airway hyperresponsiveness in mice.

CONCLUSION

These in vitro and in vivo findings highlight the importance of SCFAs, especially butyrate as a promising therapeutic agent in allergic inflammatory diseases.

The association between blood eosinophil percent and bacterial infection in acute exacerbation of chronic obstructive pulmonary disease

Introduction: The use of antibiotics is based on the clinician's experience and judgment, and antibiotics may often be overused in the treatment of acute exacerbations of chronic obstructive pulmonary disease (AECOPD). Eosinophils have been studied as biomarkers of bacterial infection and prognostic factors in chronic obstructive pulmonary disease and AECOPD. Thus, the purpose of this study was to determine whether eosinophils could be used to determine bacterial infection in AECOPD events. Methods: We retrospectively analyzed the medical records of patients admitted to Korea University Guro Hospital for AECOPD between January 2011 and May 2017. Data pertaining to baseline characteristics, results of previous pulmonary function tests, treatment information during the admission period, and history of pulmonary treatment were collected before admission. Results: A total of 736 AECOPD events were eligible for inclusion and were divided into two groups based on the eosinophil count: those involving eosinophil counts of less than 2% (546 events) and those involving counts of 2% or more (190 events). In univariate analysis, the only bacterial pathogen identification events and bacterial-viral pathogen co-identification events were significantly more frequent in the group with eosinophil counts of less than 2% (P=0.010 and P=0.001, respectively). In logistic regression analysis, the rates of only bacterial pathogen identification [odds ratios =1.744; 95% confidence interval, 1.107-2.749; P=0.017] and bacterial-viral pathogen co-identification [odds ratios=2.075; 95% confidence interval, 1.081-3.984; P=0.028] were higher in the group with eosinophil count less than 2%. Conclusion: In conclusion, eosinophil counts of less than 2% are potential indicators of a bacterial infection in AECOPD events. Eosinophils could thus serve as a reference for the use of antibiotics in AECOPD treatment.

Therapeutic potential of andrographolide-loaded nanoparticles on a murine asthma model

Corticosteroids commonly prescribed in asthma show several side-effects. Relatively non-toxic andrographolide (AG) has an anti-asthmatic potential. But its poor bioavailability and short plasma half-life constrain its efficacy. To overcome them, we encapsulated AG in nanoparticle (AGNP) and evaluated AGNP for anti-asthmatic efficacy on murine asthma model by oral/pulmonary delivery. AGNP had 5.47% drug loading with a sustained drug release in vitro. Plasma and lung pharmacokinetic data showed predominantly improved AG-bioavailability upon AGNP administered orally/by pulmonary route. Cell numbers, IL-4, IL-5, and IL-13 levels in broncho-alveolar lavage fluid and serum IgE content were reduced significantly after administration of AGNP compared to free-AG treatment. AGNP-mediated suppression of NF-κβ was predominantly more compared to free-AG. Further, pulmonary route showed better therapeutic performance. In conclusion, AGNP effectively controlled mild and severe asthma and the pulmonary administration of AGNP was more efficacious than the oral route.

Chronic pulmonary aspergillosis may cause eosinophilic granulomatosis with polyangiitis via allergic bronchopulmonary aspergillosis

An 84-year-old man visited our hospital with a prolonged productive cough. Chest computed tomography showed a thick wall cavity and bilateral consolidations. Laboratory findings revealed peripheral blood eosinophilia, increased total IgE and elevated myeloperoxidase anti-neutrophil cytoplasmic antibody. Specific IgE and IgG antibodies and an immediate skin reaction against Aspergillus showed positive results. The histological findings of the lung parenchyma were compatible with eosinophilic pneumonia and bronchial biopsy showed eosinophilic vasculitis. Bronchoalveolar lavage fluid culture yielded Aspergillus fumigatus. These results met the diagnosis criteria for both allergic bronchopulmonary aspergillosis (ABPA) and eosinophilic granulomatosis with polyangiitis (EGPA). This case thus suggests that A. fumigatus might be a pathogen common to both diseases, and prolonged exposure to A. fumigatus in some patients with ABPA may promote progression to EGPA.

The Role of Autophagy in Eosinophilic Airway Inflammation

Autophagy is a homeostatic mechanism that discards not only invading pathogens but also damaged organelles and denatured proteins via lysosomal degradation. Increasing evidence suggests a role for autophagy in inflammatory diseases, including infectious diseases, Crohn's disease, cystic fibrosis, and pulmonary hypertension. These studies suggest that modulating autophagy could be a novel therapeutic option for inflammatory diseases. Eosinophils are a major type of inflammatory cell that aggravates airway inflammatory diseases, particularly corticosteroid-resistant inflammation. The eosinophil count is a useful tool for assessing which patients may benefit from inhaled corticosteroid therapy. Recent studies demonstrate that autophagy plays a role in eosinophilic airway inflammatory diseases by promoting airway remodeling and loss of function. Genetic variant in the autophagy gene ATG5 is associated with asthma pathogenesis, and autophagy regulates apoptotic pathways in epithelial cells in individuals with chronic obstructive pulmonary disease. Moreover, autophagy dysfunction leads to severe inflammation, especially eosinophilic inflammation, in chronic rhinosinusitis. However, the mechanism underlying autophagy-mediated regulation of eosinophilic airway inflammation remains unclear. The aim of this review is to provide a general overview of the role of autophagy in eosinophilic airway inflammation. We also suggest that autophagy may be a new therapeutic target for airway inflammation, including that mediated by eosinophils.

Analysis of the predicting factors of recurrent wheezing in infants

Background

Clinically, asthma in children under 5 years old is under estimated because lack of diagnostic criteria. The current study was, therefore, designed to identify the predicting factors for recurrent wheezing in infants.

Methods

One hundred forty-five infants under 3-year old hospitalized with respiratory diseases were enrolled into this study. Patients were followed up for one-year period after being discharged from the hospital and were, then, divided into recurrent wheezing group and non-recurrent wheezing group based on whether there was recurrent wheezing or not. Wheezing or recurrent wheezing was specifically monitored in addition to blood tests for allergic and respiratory diseases.

Results

The prevalence of eczema and respiratory syncytial virus (RSV) infection were significantly higher in recurrent wheezing group than in control group (74.2% vs 45.8%; 32.3% vs. 13.3%, respectively, both P < 0.05); the percentage of blood eosinophil and serum eosinophil-derived neurotoxin (EDN) concentration at admission were also higher in recurrent wheezing group than in control group (3.10 ± 2.54% vs. 1.31 ± 1.15%; 68.67 ± 55.05 ng/mL vs. 27. 36 ± 19.51 ng/mL; respectively, both P < 0.001). Multivariate logistic regression analysis on eosinophil count and serum EDN concentration in predicting recurrent wheezing revealed that the eosinophil count showed the lowest sensitivity (51.6%) and highest specificity (90.4%), with the area under the ROC curve (AUC) of 0.752 ± 0.041; and that, in contrast, the serum EDN showed the highest sensitivity (88.7%) and lowest specificity (56.6%), with AUC of 0.795 ± 0.037.

Conclusion

Combination of eosinophil count and serum EDN measurement may be better to predict the risk of recurrent wheezing in early life of childhood.

[Eosinophilic granulocytes-Physiology and pathophysiology]

Eosinophilic granulocytes are a subpopulation of leucocytes and part of the innate immune cell pool. Additionally, they have homeostatic functions in different tissues. Classically, an increased number of eosinophils is associated with allergies and parasitic infections; however, eosinophilia can also be found in vasculitides and malignant tumors. The most important controlling factors of eosinophils are the cytokine interleukin 5 and eotaxins. Eosinophils are able to produce a broad range of signalling factors and toxic proteins, which are stored in cytoplasmic granules and can be quickly and specifically released when needed depending on the stimulus. To combat pathogens, eosinophils can catapult extracellular traps consisting of mitochondrial DNA and toxic proteins into the intercellular space. This review focuses on the basic structure, control and function of eosinophils in health and disease.

Human eosinophils and mast cells: Birds of a feather flock together

While the origin of the phrase "birds of a feather flock together" is unclear, it has been in use for centuries and is typically employed to describe the phenomenon that people with similar tastes or interests tend to seek each other out and congregate together. In this review, we have co-opted this phrase to compare innate immune cells of related origin, the eosinophil and mast cell, because they very often accumulate together in tissue sites under both homeostatic and inflammatory conditions. To highlight overlapping yet distinct features, their hematopoietic development, cell surface phenotype, mediator release profiles and roles in diseases have been compared and contrasted. What emerges is a sense that these two cell types often interact with each other and their tissue environment to provide synergistic contributions to a variety of normal and pathologic immune responses.

Eosinophil-Associated Innate IL-17 Response Promotes Aspergillus fumigatus Lung Pathology

Aspergillus fumigatus is a common widespread microorganism with environmental, biological and clinical relevance. After inhalation, swollen conidia can germinate, colonize and invade pulmonary tissues. Eosinophils have been described as key cells in A. fumigatus lung infection. However, their specific role in protecting or damaging lung tissue as well as their relatioship among different A. fumigatus strains is poorly understood. Previously, it has been reported that eosinophils are able to produce IL-17 and mediate an innate response that protected mice from infection using Af293 and CEA10 strains. Here, we have developed a set of new experiments with the CEA17-derived A1163 strain of A. fumigatus. Using ΔdblGATA1 mice, we demonstrate that eosinophils produce IL-17 and are involved in control of neutrophil, macrophage and lymphocyte recruitment. We found that eosinophils also induce high levels of cytokines and chemokines, generating an intense inflammatory process. Eosinophils are responsible for increased pulmonary dysfunction and elevated lethality rates in mice. Curiously, fungal burden was not affected. To address the role of IL-17 signaling, pharmacological inhibition of this mediator in the airways with anti-IL-17 antibody was able to reduce inflammation in the airways and protect infected mice. In conclusion, our results demonstrate that eosinophils control IL-17-mediated response and contribute to lung pathology after A. fumigatus infection. Therefore, eosinophils may represent a potential target for controlling exacerbated inflammation and prevent tissue damage during this fungal infection.

The Iron Chelator and Anticancer Agent Dp44mT Relieves Allergic Inflammation in Mice With Allergic Rhinitis

Our previous study showed that an iron chelator and anticancer agent Di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone (Dp44mT) has an antiinflammatory effect in human mast cells. However, antiinflammatory effect of Dp44mT remains unclear in animal models. In this study, we assessed whether administration of Dp44mT could relieve clinical symptoms of ovalbumin (OVA)-induced allergic rhinitis (AR) mice. After administration of Dp44mT, number of rubs was significantly decreased, and levels of histamine and IgE were suppressed in serum of AR mice. Also, serum levels of interleukin (IL)-1β, thymic stromal lymphopoietin (TSLP), and tumor necrosis factor (TNF)-α increased by OVA challenge were significantly lowered by administration of Dp44mT. T helper type 1 (Th1) cytokine interferon-γ level was significantly increased by administration of Dp44mT, whereas Th2 cytokines such as IL-4, IL-5, and IL-13 were significantly reduced by administration of Dp44mT. In intranasal tissues of AR mice, levels of IL-1β, TSLP, TNF-α, and IL-6 and activities and protein levels of caspase-1 were significantly reduced by administration of Dp44mT. Interestingly, administration of Dp44mT reduced number of infiltrated eosinophils and mast cells through the inhibition of macrophage inflammatory protein-2 and intercellular adhesion molecule-1 in intranasal tissues of AR mice. In conclusion, these results indicate that Dp44mT also has potential antiinflammatory effects in vivo as well as in vitro.

Biomarkers for Recurrent Wheezing and Asthma in Preschool Children

Wheezing is one of the characteristic symptoms of asthma, but all preschool children with wheezing are not diagnosed with asthma. Preschool children are not cooperative enough to participate in spirometry and invasive tests. Thus, there is no conventional method to diagnose asthma in preschool children. We reviewed studies on non-invasive biomarkers for assessing asthma in preschool children. Specimens that can be easily obtained by non-invasive methods are blood, exhaled breath and urine. Eosinophils, eosinophil cationic protein and eosinophil-derived neurotoxin (EDN) in blood are helpful in evaluating eosinophilic inflammation of the airways. Exhaled breath contains nitric oxide, volatile organic compounds, various cytokines and mediators as analytical components. Fraction of exhaled nitric oxide has been used to assess the degree of eosinophil inflammation and has been standardized in school-age children and adults, but not yet in preschool children. Exhaled breath condensate (EBC) pH and various cytokines/mediators that are detected in EBC seem to be promising biomarkers for assessing asthma, but need more standardization and validation. There are several biomarkers useful for assessing asthma, but none are ideal. Some biomarkers need standardized methods of obtaining samples from uncooperative preschool children for clinical use and require sufficient validation. Recently, another activated eosinophil marker, serum EDN, has shown promising results as a biomarker for recurrent wheezing and asthma in preschool children.

New pre-treatment eosinophil-related ratios as prognostic biomarkers for survival outcomes in endometrial cancer

BACKGROUND

Systemic inflammation has long been related with adverse survival outcomes in cancer patients, and its biomarkers, such as the Neutrophil-to-Lymphocyte Ratio (NLR), are recognized as poor prognostic indicators. However, the role of eosinophils in this field has been largely overlooked. Here, we describe two new pre-treatment biomarkers, expressed as Eosinophil-to-Lymphocytes Ratio (ELR) and Eosinophil*Neutrophil-to-Lymphocytes ratio (ENLR), and we analyse their impact on prognosis of endometrial cancer (EC) patients.

METHODS

A total of 163 consecutive patients diagnosed with EC and treated with postoperative radiotherapy +/- chemotherapy in our institution from January 2011 to December 2015 were evaluated. The cohort was divided in two groups applying the cut-off value of 0.1 and 0.5 according to ROC curve for pre-treatment ELR and ENLR, respectively. After patients' stratification according to the ESMO-ESGO-ESTRO modified risk assessment, subgroup analyses were conducted.

RESULTS

Higher values of ELR and ENLR were associated with worse OS (p = 0.004 and p = 0.010, respectively). On univariate analysis, the factors associated with shorter OS were ELR ≥ 0.1 (HR = 2.9, p = 0.017), ENLR ≥ 0.5 (HR = 3.0, p = 0.015), advanced FIGO stage (HR = 3.4, p = 0.007), endometrioid histology (HR = 0.26, p = 0.003) and ESMO-ESGO-ESTRO high-risk (HR = 10.2, p = 0.023). On multivariate Cox regression, higher ELR and ENLR were independently associated with a worse outcome adjusted for the standardly applied prognostic factors.

CONCLUSIONS

Increased values of ELR and ENLR portend worse OS in EC, especially in patients classified by the ESMO-ESGO-ESTRO guidelines as a high-risk group. To our best knowledge, this is the first report describing eosinophils-related ratios as prognostic biomarkers in malignant tumours.

Type 2 Inflammation and the Evolving Profile of Uncontrolled Persistent Asthma

The objective of this symposium was to provide an overview of Type 2 inflammation in asthma. The speakers covered the pathophysiology of Type 2 asthma, its heterogeneity, the associated economic burden, and methods for recognising Type 2 inflammation in severe asthma patients in clinical practice. Asthma is a heterogenous disease and multiple phenotypes are common among patients. Type 2 asthma is so named because it is associated with Type 2 inflammation and typically includes allergic asthma and moderate-to-severe eosinophilic asthma, Prof Canonica explained. By contrast, non-Type 2 asthma commonly has an older age of onset and is often associated with obesity and neutrophilic inflammation. Prof Diamant highlighted the scale and severity of uncontrolled persistent asthma. Globally, an estimated 420,000 people die of asthma every year, and many more have uncontrolled disease, putting them at risk of persistent airway inflammation and eventual lung decline. Patients may not recognise that their disease is uncontrolled, despite exacerbations and the impact of their asthma on daily activities. Prof Diamant described the impairments to health-related quality of life and the associated costs of uncontrolled asthma. Prof Dahlén outlined how new predictive biomarkers will be needed to identify the type of asthma an individual patient has. No single biomarker will provide sufficient information, and as such, in the future, profiles of many markers will need to be integrated to produce subgroup-specific profiles for use in personalised medicine. He described ongoing research into protein arrays and lipid mediators in urine, and how cluster analysis and pattern recognition, with the aid of artificial intelligence, will form the basis of future diagnostic tools. Prof Canonica explained that an understanding of the mechanisms of asthma is important in achieving better symptom control. IL-4 and IL-13 are key players in the pathobiology of uncontrolled persistent asthma (IL-4 in inflammation and IL-13 in airway remodelling), but their roles overlap. The heterogenous nature of Type 2 asthma can make it difficult to diagnose; therefore, focussing on a single biomarker is likely to leave some patients sub-optimally controlled.

Eosinophilia and Kidney Disease: More than Just an Incidental Finding?

Peripheral blood eosinophilia (PBE), defined as 500 eosinophils or above per microliter (µL) blood, is a condition that is not uncommon but often neglected in the management of patients with chronic kidney disease (CKD), acute kidney injury (AKI), or patients on renal replacement therapy (RRT). The nature of PBE in the context of kidney diseases is predominantly secondary or reactive and has to be distinguished from primary eosinophilic disorders. Nonetheless, the finding of persistent PBE can be a useful clue for the differential diagnosis of underdiagnosed entities and overlapping syndromes, such as eosinophilic granulomatosis with polyangiitis (EGPA), IgG4-related disease (IgG4-RD), acute interstitial nephritis (AIN), or the hypereosinophilic syndrome (HES). For patients on RRT, PBE may be an indicator for bio-incompatibility of the dialysis material, acute allograft rejection, or Strongyloides hyperinfection. In a subset of patients with EGPA, eosinophils might even be the driving force in disease pathogenesis. This improved understanding is already being used to facilitate novel therapeutic options. Mepolizumab has been licensed for the management of EGPA and is applied with the aim to abrogate the underlying immunologic process by blocking interleukin-5. The current article provides an overview of different renal pathologies that are associated with PBE. Further scientific effort is required to understand the exact role and function of eosinophils in these disorders which may pave the way to improved interdisciplinary management of such patients.

Innate Lymphoid Cells (ILCs): Cytokine Hubs Regulating Immunity and Tissue Homeostasis

Innate lymphoid cells (ILCs) have emerged as an expanding family of effector cells particularly enriched in the mucosal barriers. ILCs are promptly activated by stress signals and multiple epithelial- and myeloid-cell-derived cytokines. In response, ILCs rapidly secrete effector cytokines, which allow them to survey and maintain the mucosal integrity. Uncontrolled action of ILCs might contribute to tissue damage, chronic inflammation, metabolic diseases, autoimmunity, and cancer. Here we discuss the recent advances in our understanding of the cytokine network that modulate ILC immune responses: stimulating cytokines, signature cytokines secreted by ILC subsets, autocrine cytokines, and cytokines that induce cell plasticity.

[Eosinopenia in 2018]

Since 1893, eosinopenia is a biological test to help a diagnosis of bacterial infection. Several publications have confirmed this hypothesis, particularly in the intensive care, pneumology and pediatric units. The value of this marker has been identified in vascular cerebral diseases and coronary bypass. Its contribution seems as relevant as procalcitonin, without extra cost. The diagnostic performance of this test was reinforced by a composite score (CIBLE score) that may improve its value in daily routine. Finally, monitoring eosinopenia appears to be a reliable mortality marker.

Eosinophil Extracellular Traps and Inflammatory Pathologies-Untangling the Web!

Eosinophils are an enigmatic white blood cell, whose immune functions are still under intense investigation. Classically, the eosinophil was considered to fulfill a protective role against parasitic infections, primarily large multicellular helminths. Although eosinophils are predominantly associated with parasite infections, evidence of a role for eosinophils in mediating immunity against bacterial, viral, and fungal infections has been recently reported. Among the mechanisms by which eosinophils are proposed to exert their protective effects is the production of DNA-based extracellular traps (ETs). Remarkably, DNA serves a role that extends beyond its biochemical function in encoding RNA and protein sequences; it is also a highly effective substance for entrapment of bacteria and other extracellular pathogens, and serves as valuable scaffolding for antimicrobial mediators such as granule proteins from immune cells. Extracellular trap formation from eosinophils appears to fulfill an important immune response against extracellular pathogens, although overproduction of traps is evident in pathologies. Here, we discuss the discovery and characterization of eosinophil extracellular traps (EETs) in response to a variety of stimuli, and suggest a role for these structures in the pathogenesis of disease as well as the establishment of autoimmunity in chronic, unresolved inflammation.

Overlapping Effects of New Monoclonal Antibodies for Severe Asthma

Among the monoclonal antibodies (mAbs) developed for severe asthma treatment, three have already been marketed. Omalizumab was the first, more than 10 years ago; today, mepolizumab and reslizumab are also available in the European Union and the US. Omalizumab blocks free immunoglobulin E (IgE), mepolizumab and reslizumab block an interleukin (IL-5). In the near future, dupilumab and benralizumab are expected to emerge as two new alternatives. Benralizumab blocks the receptor for IL-5 (IL5-Rα) and has a direct cytotoxic effect on eosinophils, and dupilumab blocks the α-unit of the heterodimeric receptor for IL-4 and IL-13 (IL-4Rα); as a result, dupilumab can block both IL-4 and IL-13. The purpose of this manuscript is to present the pathophysiology of some immunological aspects of severe asthma, describe the adaptive and innate immunity arms as well as their interrelations (stressing the subordination of the adaptive arm to the innate arm), outline the pharmacologic effects of these mAbs, clarify the overlapping effects of the different mAbs, and discuss the differences between mAbs based on their target molecules. Based on the data presented, I propose omalizumab for patients with an allergic phenotype regardless of their peripheral eosinophilic count, and anti-IL-5 as an alternative in allergic patients with blood eosinophilia in which omalizumab has failed; anti-IL5 for patients with an eosinophilic phenotype and omalizumab as an alternative in patients in whom anti-IL5 fails and IgE ≥30 IU/mL (compassionate use). Omalizumab is also proposed for patients with severe chronic asthma allergic to seasonal allergens.

Effects of Diet-Induced Obesity on Tracheal Responsiveness to Methacholine, Tracheal Visfatin Level, and Lung Histological Changes in Ovalbumin-Sensitized Female Wistar Rats

Many studies have shown a close relationship between obesity and asthma severity. In the present study, the effects of diet-induced obesity were examined on airway responsiveness to methacholine in addition to visfatin level in female Wistar rats' tracheae after sensitization with ovalbumin. The rats were divided into four groups: control with normal diet (ND), ovalbumin (OVA)-sensitized with normal diet (S + ND), high-fat diet (HFD), and OVA-sensitized with a high-fat diet (S + HFD). The animals were fed for 8 weeks with standard pelts or high-fat diet and then sensitized and challenged with OVA or saline for another 4 weeks. At the end of the study, the tracheae were isolated and assessed for airway responsiveness and visfatin protein levels. Diet-induced obesity groups developed increased weight and obesity indices (p < 0.001). After sensitization with OVA and diet-induced obesity, there were marked leftward shifts in methacholine concentration-response curves in S + HFD group compared to other groups. Also, maximum response was the highest (p < 0.05 to p < 0.001), EC₅₀ was the lowest (p < 0.05 to p < 0.001), and visfatin protein level was the highest (p < 0.05 to p < 0.01) in S + HFD. According to results, diet-induced obesity caused airway hyperresponsiveness to methacholine and enhanced visfatin protein levels in the tracheae of ovalbumin-sensitized female rats. Our results suggested that, in obese ovalbumin-sensitized conditions in female rats, the local production of adipocytokines, such as visfatin, may be increased, resulting in the deterioration of inflammation in lungs. This finding shows a possible mechanism for the altered phenotype in obesity-ovalbumin sensitization conditions in female rats.

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.

An Approach to the Evaluation of Persistent Hypereosinophilia in Pediatric Patients

Hypereosinophilia (HE) is currently defined by a peripheral blood absolute eosinophil count (AEC) of ≥1,500 cells/microL. Although mild blood eosinophilia (AEC 500–1,500 cells/microL) is observed relatively frequently within the pediatric population, persistent HE is uncommon and should prompt additional clinical evaluation. While the clinical manifestations and underlying etiologies of HE in adults have been well-characterized, there is a paucity of data on HE in children. Limited evidence suggests that many similarities between adult and pediatric HE likely exist, but some important differences remain between these populations. The evaluation of HE in children can be challenging given the broad differential diagnosis, which includes primary hematologic disorders and secondary eosinophilia in which the increased eosinophil levels are propagated by disease states that promote eosinophil production and survival. On the basis of the underlying etiology, clinical manifestations can range from benign, self-resolving elevations in the AEC to life-threatening disorders with the potential for significant end-organ damage. Given the broad differential diagnosis of HE, it remains essential to systematically approach the evaluation of unexplained HE in children. This review will discuss the differential diagnosis for pediatric HE, highlighting etiologies that are more prevalent within the pediatric population. Additionally, a summary of the epidemiology of pediatric HE will be presented, with focus on some of the differences that exist between pediatric and adult HE. Finally, a directed approach to the diagnostic evaluation of children with HE will be discussed.

Testosterone Decreases House Dust Mite-Induced Type 2 and IL-17A-Mediated Airway Inflammation

As adults, women are twice as likely as men to have asthma; however, the mechanisms explaining this sexual dimorphism remain unclear. Increased type 2 cytokines and/or IL-17A, leading to increased airway eosinophils and neutrophils, respectively, are associated with asthma. Previous studies showed that testosterone, signaling through the androgen receptor (AR), decreased Th2-mediated allergic inflammation and type 2 innate immune responses during allergic inflammation. Therefore, we hypothesized that testosterone and AR signaling attenuate type 2 and IL-17A-mediated airway inflammation. To test our hypothesis, sham-operated and gonadectomized female and male mice were intranasally challenged with house dust mite (HDM) or vehicle (PBS) for 3 wk. Testosterone decreased and ovarian hormones increased HDM-induced eosinophilic and neutrophilic inflammation, IgE production, and airway hyperresponsiveness, as well as decreased the numbers of IL-13⁺ CD4 Th2 cells and IL-17A⁺ CD4 Th17 cells in the lung. Next, using wild-type male and female mice and AR^tfm male mice that are unable to signal through the AR, we determined AR signaling intrinsically attenuated IL-17A⁺ Th17 cells but indirectly decreased IL-13⁺ CD4 Th2 cells in the lung by suppressing HDM-induced IL-4 production. In vitro Th2 and Th17 differentiation experiments showed AR signaling had no direct effect on Th2 cell differentiation but decreased IL-17A protein expression and IL-23R mRNA relative expression from Th17 cells. Combined, these findings show AR signaling attenuated type 2 and IL-17A inflammation through different mechanisms and provide a potential explanation for the increased prevalence of asthma in women compared with men.

Peripheral eosinophilia in bullous pemphigoid: prevalence and influence on the clinical manifestation

BACKGROUND

Peripheral eosinophilia has been reported in 50-60% of patients with bullous pemphigoid (BP) and correlated positively with disease severity.

OBJECTIVES

To establish an association of peripheral eosinophilia with the different morphological characteristics of BP.

METHODS

The study was designed as a case-control study. Diagnosis of BP was grounded on well-established immunopathological criteria. Five age-, sex- and ethnicity-matched controls were randomly selected for each patient with BP.

RESULTS

Overall, 225 patients with BP and 1125 control participants were enrolled. A total of 113 (50·2%) patients with BP and 49 (4·4%) controls had pathological peripheral eosinophilia (P < 0·001). An independent association between eosinophil count and the diagnosis of BP was observed [odds ratio 59·9 (per 1000 eosinophil μL^-1 increase); P < 0·001]. Patients with BP with eosinophilia were significantly older at presentation (P = 0·003) and had increased palmoplantar involvement (P = 0·005), whereas patients with normal eosinophil counts had greater involvement of mucosal surfaces (P = 0·002) and the head and neck (P = 0·047). Patients with BP with extensive disease had significantly higher eosinophil counts than patients with mild-to-moderate disease (996·5 ± 1052·5 vs. 696·1 ± 962·6 cells μL^-1 ; P < 0·001).

CONCLUSIONS

Patients with BP with serum eosinophilia were significantly older and had higher palmoplantar involvement. Patients with BP with a normal eosinophil count were younger and presented more frequently with atypical clinical manifestations.

Diagnosis, Natural History and Treatment of Eosinophilic Enteritis: a Review

PURPOSE OF REVIEW

To review recent findings regarding eosinophilic enteritis, including epidemiology, pathogenesis, natural history, and treatment.

RECENT FINDINGS

A 2017 population-based study using a US healthcare system database identified 1820 patients with a diagnosis of eosinophilic enteritis among 35,826,830 individuals. The majority of patients with eosinophilic enteritis in this study were women (57.7%), Caucasian (77.5%), and adults (> 18 years of age) (83.5%). The overall prevalence of eosinophilic enteritis was estimated at 5.1/100,000 persons. Eosinophilic enteritis, also known as eosinophilic gastroenteritis, is a rare primary eosinophilic gastrointestinal disorder (EGID) of unknown etiology characterized by the presence of an intense eosinophilic infiltrate on histopathological examination of the intestinal mucosa. The etiology of eosinophilic enteritis remains unknown. However, there is evidence to support the role of allergens in the pathogenesis of this disorder, as children and adults with EGIDs often have positive skin testing to food allergens and a family history of allergic diseases. Recent studies unraveling the role of IgE-mediated but also delayed Th2-type responses have provided insight into the pathogenesis of this disease. Eosinophilic enteritis causes a wide array of gastrointestinal symptoms such as abdominal pain, diarrhea, nausea, vomiting, bloating, or ascites, and its diagnosis requires a high degree of clinical likelihood, given the nonspecific clinical presentation and physical examination findings. Oral corticosteroids are considered to be the mainstay of treatment and are generally used for a short period with good response rates. Antihistamine drugs and sodium cromoglycate have also been used to treat patients with eosinophilic enteritis. Preliminary studies have demonstrated the potential benefit of biological therapies targeting the eosinophilic pathway such as mepolizumab, an anti-IL5 antibody, or omalizumab, an anti-IgE monoclonal antibody. Eosinophilic enteritis is generally considered to be a benign disease without relapse, but up to 50% of patients may present a more complex natural history characterized by unpredictable relapses and a chronic course.

Vesicle-associated membrane protein 7-mediated eosinophil degranulation promotes allergic airway inflammation in mice

Eosinophil degranulation is a determining factor in allergy-mediated airway pathology. Receptor-mediated degranulation in eosinophils requires vesicle-associated membrane protein 7 (VAMP-7), a principal component of the SNARE fusion machinery. The specific contribution of eosinophil degranulation to allergen-induced airway responses remains poorly understood. We generated mice with VAMP-7 gene deficiency exclusively in eosinophils (eoCRE/V7) from a cross using eosinophil-specific Cre recombinase-expressing mice crossed with VAMP-7^f/f mice. Eosinophils from eoCRE/V7 mice showed deficient degranulation responses in vitro, and responses continued to be decreased following ex vivo intratracheal adoptive transfer of eoCRE/V7 eosinophils into IL-5/hE2/EPX^−/− mice. Consistent with diminished degranulation responses, reduced airway hyperresponsiveness was observed in ovalbumin-sensitized and challenged eoCRE/V7 mice following methacholine inhalation. Therefore, VAMP-7 mediates eosinophil degranulation both in vitro and ex vivo, and this event augments airway hyperresponsiveness.

Lian Willetts et al. demonstrate that vesicle-associated membrane protein 7 (VAMP 7), a principal component of the membrane fusion machinery, promotes eosinophil degranulation in allergic airway inflammation. This study suggests VAMP7 as a therapeutic target for ameliorating asthma.

What Can Pleiotropic Proteins in Innate Immunity Teach Us about Bioconjugation and Molecular Design?

A common bioengineering strategy to add function to a given molecule is by conjugation of a new moiety onto that molecule. Adding multiple functions in this way becomes increasingly challenging and leads to composite molecules with larger molecular weights. In this review, we attempt to gain a new perspective by looking at this problem in reverse, by examining nature's strategies of multiplexing different functions into the same pleiotropic molecule using emerging analysis techniques such as machine learning. We concentrate on examples from the innate immune system, which employs a finite repertoire of molecules for a broad range of tasks. An improved understanding of how diverse functions are multiplexed into a single molecule can inspire new approaches for the deterministic design of multifunctional molecules.

Hypoxia, Metabolism and Immune Cell Function

Hypoxia is a hallmark of inflamed, infected or damaged tissue, and the adaptation to inadequate tissue oxygenation is regulated by hypoxia-inducible factors (HIFs). HIFs are key mediators of the cellular response to hypoxia, but they are also associated with pathological stress such as inflammation, bacteriological infection or cancer. In addition, HIFs are central regulators of many innate and adaptive immunological functions, including migration, antigen presentation, production of cytokines and antimicrobial peptides, phagocytosis as well as cellular metabolic reprogramming. A characteristic feature of immune cells is their ability to infiltrate and operate in tissues with low level of nutrients and oxygen. The objective of this article is to discuss the role of HIFs in the function of innate and adaptive immune cells in hypoxia, with a focus on how hypoxia modulates immunometabolism.

Allergic diseases: From bench to clinic - Contribution of the discovery of interleukin-5

T helper 2 cells produce a number of cytokines including inteleukin (IL)-5, IL-4 and IL-13. Group 2 innate lymphoid cells (ILC2s) also produce IL-5 under sterile conditions. IL-5 is interdigitating homodimeric glycoprotein and a member of the four α helical bundle motifs conserved among hematopoietic cytokines. IL-5 exerts its effects on target cells via IL-5 receptor (IL-5R), composed of an IL-5R α and βc subunit. The membrane proximal proline-rich motif of the cytoplasmic domain of both IL-5R α and βc subunits is essential for IL-5 signal transduction. Although IL-5 was initially identified by its ability to support the growth and terminal differentiation of mouse B cells into antibody-secreting cells, recombinant IL-5 exerts pleiotropic activities on various target cells. For example, IL-5 is now recognized as the major maturation and differentiation factor for eosinophils in mice and humans. Overexpression of IL-5 in mouse significantly increases eosinophil numbers and antibody levels in vivo, while mice lacking a functional gene for IL-5 or IL-5R display developmental and functional impairments in B cell and eosinophil lineages. In mice, the role of the IL-5/IL-5R system in the production and secretion of Immunoglobulin (Ig) M and IgA in mucosal tissues has been reported. Although eosinophils protect against invading pathogens including virus, bacteria and helminthes, they are also involved in the pathogenesis of various diseases, such as food allergy, asthma, and inflammatory bowel diseases. The recent expansion in our understanding in the context of IL-5 and IL-5-producing ILC2s in eosinophil activation and the pathogenesis of eosinophil-dependent inflammatory diseases has led to advances in therapeutic options. A new therapy currently under invetigarion in clinical trials uses humanized monoclonal antibodies against IL-5 or the IL-5R. In this review, we summarize our current understanding of the functions of IL-5 and its receptor, the innate regulation of IL-5-producing cells, and therapeutic potential of anti-IL-5 and anti-eosinophil (IL-5R) antibodies.

Anti-inflammatory effect of wogonin on allergic responses in ovalbumin-induced allergic rhinitis in the mouse

Background

Wogonin is commonly used for the treatment of allergic diseases. However, neither its precise effect in preventing allergic rhinitis (AR) nor its mechanism of action are known.

Objectives

In this study, the effect of wogonin on allergic responses in ovalbumin (OVA) induced AR was investigated in mice.

Methods

BALB/c mice were sensitized with intraperitoneal (i.p.) OVA and then challenged intranasally with OVA. Wogonin (10 and 30 mg/kg) was given to the treatment groups, and the effect of wogonin on the release of allergic inflammatory mediators, specifically OVA-specific immunoglobulin E (IgE) and inflammatory cytokines, was explored. Eosinophil infiltration and the levels of interleukin (IL) 5 and IL-13 were measured by immunohistochemistry.

Results

In mice with AR, wogonin decreased OVA-specific IgE levels in serum, and the levels of the cytokines IL-4, IL-5, IL-13, eotaxin, and RANTES in nasal lavage fluid. Serum levels of IL-4, IL-5, and IL-13 were lower in both groups of wogonin-pretreated mice than in the OVA group. A reduction in eosinophil infiltration of the nasal mucosa and inhibition of the expression of IL-5 and IL-13 were also noted in the treated groups.

Conclusion

Wogonin induced antiallergic effects in a murine model of AR by decreasing the infiltration of eosinophils and levels of T-helper type 2 cytokines. Thus, wogonin merits consideration as a therapeutic agent for treating AR.

Important and specific role for basophils in acute allergic reactions

IgE‐mediated allergic reactions involve the activation of effector cells, predominantly through the high‐affinity IgE receptor (FcεRI) on mast cells and basophils. Although the mast cell is considered the major effector cell during acute allergic reactions, more recent studies indicate a potentially important and specific role for basophils and their migration which occurs rapidly upon allergen challenge in humans undergoing anaphylaxis. We review the evidence for a role of basophils in contributing to clinical symptoms of anaphylaxis and discuss the possibility that basophil trafficking during anaphylaxis might be a pathogenic (to target organs) or protective (preventing degranulation in circulation) response. Finally, we examine the potential role of basophils in asthma exacerbations. Understanding the factors that regulate basophil trafficking and activation might lead to new diagnostic and therapeutic strategies in anaphylaxis and asthma.

Benralizumab in the treatment of severe asthma: design, development and potential place in therapy

Asthma is a widespread and heterogeneous inflammatory disease of the airways, which is characterized by several different phenotypes and endotypes. In particular, eosinophilic airway inflammation is a common pathologic trait of both allergic and nonallergic asthma. The key cytokine responsible for maturation, activation, recruitment, and survival of eosinophils is interleukin (IL)-5, which is mainly produced by T helper 2 (Th2) lymphocytes and group 2 innate lymphoid cells. Therefore, for uncontrolled patients with severe eosinophilic asthma, who are not fully responsive to corticosteroids, IL-5 represents a very important molecular target for add-on biological therapies. Among these new treatments, anti-IL-5 monoclonal antibodies such as mepolizumab and reslizumab have been developed and clinically evaluated. Furthermore, benralizumab is currently the only available biologic drug that specifically binds to the IL-5 receptor, thus preventing the interaction with its ligand and the consequent pro-inflammatory effects. The effectiveness of benralizumab in improving severe eosinophilic asthma has been well-documented by many randomized controlled trials.

The impacts of pretreatment circulating eosinophils and basophils on prognosis of stage Ⅰ-Ⅲ colorectal cancer

AIM

The effects of circulating eosinophils and basophils on cancer survival are unclear. Here, we aimed to explore the impacts of eosinophils and basophils on prognosis of stage I-III colorectal cancer (CRC) patients.

METHODS

From February 2003 to March 2013, 569 stage I-III CRC patients were enrolled in this retrospective study. The associations between pretreatment circulating eosinophils, basophils and CRC overall survival (OS), disease-free survival (DFS) were investigated. Moreover, the prognostic value of combined eosinophils/basophils and neutrophil to lymphocyte ratio (NLR)/platelet to lymphocyte ratio (PLR) was investigated.

RESULTS

Kaplan-Meier methods showed the associations of eosinophils < 0.095 × 10⁹ /L and shorter OS (P < 0.0001), eosinophils < 0.055 × 10⁹ /L and shorter DFS (P < 0.0001), basophils < 0.015 × 10⁹ /L and shorter OS (P = 0.001), basophils < 0.015 × 10⁹ /L and shorter DFS (P = 0.005). Cox regression model showed that eosinophils < 0.095 × 10⁹ /L (hazard ratio [HR], 1.723; 95% confidence intervals [CI] = 1.177-2.523) and basophils < 0.015 × 10⁹ /L (HR, 1.714; 95% CI = 1.152-2.548) were independent prognostic factors for OS, and eosinophils < 0.055 × 10⁹ /L (HR, 2.309; 95% CI = 1.587-3.361) and basophils < 0.015 × 10⁹ /L (HR, 1.397; 95% CI = 1.003-1.945) were independent prognostic factors for DFS, respectively. The combined eosinophil-PLR (HR, 2.611; 95% CI = 1.328-5.130) and basophil-PLR (HR, 2.520; 95% CI = 1.240-5.123) were the independent prognostic factors for OS. The combined eosinophil-NLR (HR, 2.770; 95% CI = 1.528-5.019) and eosinophil-PLR (HR, 4.788; 95% CI = 2.458-9.329) were the independent prognostic factors for DFS.

CONCLUSION

Pretreatment circulating eosinophils < 0.095 × 10⁹ /L/0.055 × 10⁹ /L and circulating basophils < 0.015 × 10⁹ /L have significant impacts on prognosis of stage I-III CRC patients.

Integrin αM activation and upregulation on esophageal eosinophils and periostin-mediated eosinophil survival in eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is an increasingly recognized allergic disease associated with dysphagia and esophageal fibrosis. We aimed to determine expression patterns of specific eosinophil integrins that promote eosinophilic infiltration of the esophageal epithelium, and to determine how key EoE-related cytokines influence eosinophil activation and survival. Esophageal and peripheral eosinophils were isolated from 20 adult subjects with EoE for immunophenotyping and integrin profiling using multicolor flow cytometry and immunohistochemistry. Expression signatures of eosinophil integrins were further assessed by immunohistochemistry using serial sections of esophageal biopsy specimens. Purified eosinophils were used to assess the effect of EoE-relevant cytokines and recombinant periostin on expression of known eosinophil integrins and eosinophil survival and activation. We found that resting eosinophils express high levels of the β2-pairing integrins αL and αM, and lower levels of α4, α6 and α4β7. The migration of peripheral eosinophils to the esophagus is characterized by the specific induction of αM, and a significant increase in the proportion of αM in high-activity conformation. Periostin, a secreted extracellular matrix protein that is significantly overexpressed in EoE, enhances eosinophil survival, and this effect is mediated by αM interaction. Integrin αM is a specific marker of activated tissue eosinophils in EoE, and promotes eosinophil survival through interactions with periostin. The ability of αMβ2 to mediate eosinophil tissue residency via periostin represents a key mechanism for disease development and a potential therapeutic target in EoE.

Mast cells, basophils and eosinophils: From allergy to cancer

Basophils, eosinophils and mast cells were first recognized by Paul Ehrlich in the late 19th century. These cells have common, but non-redundant roles, in the pathogenesis of allergic diseases and in the protection against parasites. Nevertheless, in virtue of their shared-adeptness to produce a huge variety of immunological mediators and express membrane-bound receptors, they are able to interact with immune and non-immune components of the tissue microenvironment, contributing to the regulation of tissue homeostasis and immune response while participating to further deregulation of tissues transforming into neoplasia.

Eosinophils from Physiology to Disease: A Comprehensive Review

Despite being the second least represented granulocyte subpopulation in the circulating blood, eosinophils are receiving a growing interest from the scientific community, due to their complex pathophysiological role in a broad range of local and systemic inflammatory diseases as well as in cancer and thrombosis. Eosinophils are crucial for the control of parasitic infections, but increasing evidence suggests that they are also involved in vital defensive tasks against bacterial and viral pathogens including HIV. On the other side of the coin, eosinophil potential to provide a strong defensive response against invading microbes through the release of a large array of compounds can prove toxic to the host tissues and dysregulate haemostasis. Increasing knowledge of eosinophil biological behaviour is leading to major changes in established paradigms for the classification and diagnosis of several allergic and autoimmune diseases and has paved the way to a "golden age" of eosinophil-targeted agents. In this review, we provide a comprehensive update on the pathophysiological role of eosinophils in host defence, inflammation, and cancer and discuss potential clinical implications in light of recent therapeutic advances.

Quail egg homogenate alleviates food allergy induced eosinophilic esophagitis like disease through modulating PAR-2 transduction pathway in peanut sensitized mice

The present pharmacotherapy for eosinophilic esophagitis (EoE) fundamentally depend on inhaled corticosteroids. Despite the fact that oral intake of topical steroids can be successful in restricting EoE-related inflammation, there are concerns with respect to the long term utilization of steroids, especially in kids. In the current research, we assess the effect of quail egg, which is reportedly a known serine protease inhibitor, on symptomatology and immune responses in a peanut-sensitized mouse model of food allergy induced EoE. Daily oral treatment with quail egg attenuated mice symptomatology and immune response. Treatment with quail egg inhibited antigen-prompted increments in mouse tryptase and eosinophil cationic protein (ECP) in serum and eosinophil in inflamed tissues like oesophagus, lung, and digestive system. Quail egg treatment resulted in decreased antibody specific IgE and IgG1 and a variety of inflammatory genes that were abnormally expressed in EoE. Other effects included increased IL-10, decreased PAR-2 activation and NF-kB p65 in inflamed tissues. Our results suggest that quail egg treatment may have therapeutic potential in attenuating the symptoms of food allergy induced EoE like disease through regulating PAR-2 downstream pathway by blocking the activation of the transcription factor NF-kB p65 activity.

Role of eosinophils in airway inflammation of chronic obstructive pulmonary disease

COPD is a significant cause of morbidity and mortality. In some patients with COPD, eosinophils contribute to inflammation that promotes airway obstruction; approximately a third of stable COPD patients have evidence of eosinophilic inflammation. Although the eosinophil threshold associated with clinical relevance in patients with COPD is currently subject to debate, eosinophil counts hold potential as biomarkers to guide therapy. In particular, eosinophil counts may be useful in assessing which patients may benefit from inhaled corticosteroid therapy, particularly regarding exacerbation prevention. In addition, several therapies targeting eosinophilic inflammation are available or in development, including monoclonal antibodies targeting the IL5 ligand, the IL5 receptor, IL4, and IL13. The goal of this review was to describe the biologic characteristics of eosinophils, their role in COPD during exacerbations and stable disease, and their use as biomarkers to aid treatment decisions. We also propose an algorithm for inhaled corticosteroid use, taking into consideration eosinophil counts and pneumonia history, and emerging eosinophil-targeted therapies in COPD.

Peripheral Eosinophilia and Clinico-radiological Characteristics among Health Screening Program Recipients

Background

Eosinophilia is well recognized in specific conditions. The objective of the present study was to determine clinico-radiologic characteristics of eosinophilia and changes in prevalence over 10 years in recipients of private health screening program at a tertiary hospital in Korea.

Methods

Data of private health screening program recipients at the health promotion center of Chung-Ang University Hospital from 2004 to 2013 were collected. Health-related questionnaires and laboratory findings of private health screening program with possible relation with eosinophilia were reviewed. Results of enzyme-linked immunosorbent assay (ELISA) for parasite, chest computed tomography, and pulmonary function test were also reviewed.

Results

The cumulative prevalence of eosinophilia was 4.0% (1,963 of 48,928). Prevalence of eosinophilia showed a decreased trend from 2004 to 2013. Most cases (96.6%) had mild degree of eosinophilia. Eosinophilic subjects were older and male-predominant. They showed lower levels of forced expiratory volume in 1 second (FEV₁%), forced vital capacity (FVC%), and FEV₁/FVC than those without eosinophilia. Eosinophilic subjects showed higher positive rate for common parasite in ELISA than those without eosinophilia. On radiologic findings, consolidation and ground glass opacities were positively associated with the degree of eosinophilia. When eosinophil was classified based on severity, statistically significant correlation between the severity of eosinophil and radiologic abnormalities was found.

Conclusion

Eosinophilia is uncommon in healthy population. It usually occurs at a mild degree. Eosinophilic patients have more radiologic abnormalities compared to those without eosinophilia. Such radiologic abnormalities are associated with the severity of eosinophilia.

Oxidative stress and cellular pathways of asthma and inflammation: Therapeutic strategies and pharmacological targets

Asthma is a complex inflammatory disease characterized by airway inflammation and hyperresponsiveness. The mechanisms associated with the development and progression of asthma have been widely studied in multiple populations and animal models, and these have revealed involvement of various cell types and activation of intracellular signaling pathways that result in activation of inflammatory genes. Significant contributions of Toll-like-receptors (TLRs) and transcription factors such as NF-кB, have been reported as major contributors to inflammatory pathways. These have also recently been associated with mechanisms of oxidative biology. This is of important clinical significance as the observed inefficacy of current available treatments for severe asthma is widely attributed to oxidative stress. Therefore, targeting oxidizing molecules in conjunction with inflammatory mediators and transcription factors may present a novel therapeutic strategy for asthma. In this review, we summarize TLRs and NF-кB pathways in the context of exacerbation of asthma pathogenesis and oxidative biology, and we discuss the potential use of polyphenolic flavonoid compounds, known to target these pathways and possess antioxidant activity, as potential therapeutic agents for asthma.

Different durations of whole raw soybean supplementation during the prepartum period: Measures of cellular immune function in transition cows

The objective of this study was to evaluate different durations of whole raw soybean (WS) supplementation (diet rich in n-6 fatty acid) during the prepartum period on cellular immune function of dairy cows in the transition period and early lactation. Thirty-one Holstein cows were used in a completely randomized design and assigned to 4 experimental groups (G) [G90, G60, G30, and G0 (control)] supplemented with a diet containing 12% of WS from 90, 60, 30 and 0 d relative to the calving date, respectively. Cows were dried off 60 d before the expected calving date. After parturition, all cows were fed a diet containing 12% of WS until 84 DIM. Blood samples were collected before the morning feeding (d -56 ± 2, -28 ± 2, -14 ± 2, -7 ± 2, at the day of partum, 7 ± 2, 14 ± 2, 28 ± 2, and 56 ± 2 relative to parturition). Cell phenotyping and phagocytosis assays were carried out using monoclonal antibodies and flow cytometry technique. Duration of WS supplementation linearly increased the percentage of blood CD3+ cells, as well as increased the percentage of blood CD8+ cells in the postpartum period, notably in G30, whereas the lowest values were observed in G0. Further, the duration of WS supplementation linearly increased the reactive oxygen species median fluorescence intensity of CH138+ cells after phagocytizing Staphylococcus aureus in the postpartum period. Longer periods of WS supplementation linearly increased phagocytosis median fluorescence intensity of CH138+ cells in the prepartum period of cows. Duration of WS supplementation linearly increased the percentage of blood CD14+ cells producing reactive oxygen species when stimulated either by Staph. aureus or Escherichia coli in the postpartum period. In conclusion, longer periods of WS supplementation during late lactation and the dry period (beginning on d 90 of the expected calving date) alter the leukocyte population and improve neutrophil immune response in the postpartum period with no detrimental effects on cow performance.

High-fat diet-induced obesity impairs insulin signaling in lungs of allergen-challenged mice: Improvement by resveratrol

Insulin resistance plays an important role in obesity-associated asthma exacerbations. Using a murine model of allergic airway inflammation, we evaluated the insulin signaling transmission in lungs of obese compared with lean mice. We further evaluated the effects of the polyphenol resveratrol in the pulmonary insulin signaling. In lean mice, insulin stimulation significantly increased phosphorylations of AKT, insulin receptor substrate 1 (IRS-1) and insulin receptor β (IRβ) in lung tissue and isolated bronchi (p < 0.05), which were impaired in obese group. Instead, obese mice displayed increased tyrosine nitrations of AKT, IRβ and IRS-1 (p < 0.05). Two-week therapy of obese mice with resveratrol (100 mg/kg/day) restored insulin-stimulated AKT, IRS-1 and IRβ phosphorylations, and simultaneously blunted the tyrosine nitration of these proteins. Additionally, the c-Jun N-terminal kinase (JNK) and inhibitor of NF-κB Kinase (IκK) phosphorylations were significantly increased in obese group, an effect normalized by resveratrol. In separate experiments, the inducible nitric oxide synthase (iNOS) inhibitor aminoguanidine (20 mg/kg/day, three weeks) mimicked the protective effects exerted by resveratrol in lungs of obese mice. Lungs of obese mice display nitrosative-associated impairment of insulin signaling, which is reversed by resveratrol. Polyphenols may be putative drugs to attenuate asthma exacerbations in obese individuals.

[A predictive bacterial infection score according to eosinophil level: An observational study]

INTRODUCTION

Several studies have shown that eosinopenia less than 0.04g/L is a marker of bacterial infection in the presence of unexplained inflammatory syndrome. The aim of our study was to test this hypothesis and to propose a predictive score for bacterial infection (score CIBLE, C reactive protein, bacterial infections, levels of leucocytes and eosinophils).

PATIENTS AND METHODS

This was a single-center observational study of patients admitted to an internal medicine department in the year 2015 and presenting with an inflammatory biological syndrome. Patients were divided into 2 groups: bacterial infections (group 1) and nonbacterial inflammatory diseases (group 2).

RESULTS

One hundred and ninety patients were included: 92 men (48.4 %) and 98 women (51.6 %). Mean age was 73.5±18.2 years [19-104]. Group 1 consisted of 124 patients (65.2 %) and group 2 of 66 patients (34.8 %). ROC analysis confirmed a cut-off level for eosinophils count at 0.04g/L as discriminant to predict bacterial infection. In a multivariate analysis, the eosinophil/neutrophil ratio, a history of COPD, the C reactive protein concentration, patient age and initial temperature were the most significant variables. They were used to build the CIBLE score. For a score higher than or equal to 87, the probability of a bacterial infection is at least 70 %.

CONCLUSION

The CIBLE score appears to be a relevant and inexpensive tool to establish a probability for bacterial infection.