Eosinophilia: a pragmatic approach to diagnosis and treatment

Prediction of helminthiases in travellers and migrants with eosinophilia: a cohort study

OBJECTIVES

The aim of this study was to determine predictors for helminthiasis among travellers and migrants with eosinophilia for which a visto to tropical regions or endemic regions for common helminthiasis had been registered.

METHODS

A retrospective cohort study was performed using electronic health records of 23,905 patients with eosinophilia (January-2011 to August-2021) at Karolinska University Hospital, (Stockholm), including patients tested for helminthiasis with a registered stay in a helminth endemic region. Outcomes were diagnosis of any helminthiasis, and diagnosis of schistosomiasis and strongyloidiasis. Multivariable logistic regression was used to assess associations between potential predictors and helminthiases with a backwards stepwise elimination approach until a predictive model was reached in which each variable had a p-value<0.15.

RESULTS

Of 1,112 eligible patients with eosinophilia and documented stay in endemic regions, 219 (19.7%) had been diagnosed with helminthiasis, most frequently schistosomiasis (n=95, 43.4%) and strongyloidiasis (n=64, 29.2%). A stay in Sub-Saharan Africa (SSA),(OR 8.2 [95%CI 2.44-27.56]), malaise and fatigue (OR 2.65 [0.77-9.09]) and high-grade eosinophilia >1500cells/μl, (2.26, [1.54-3.32]) were the most important predictors for any helminthiasis (AUC: 0.77 [0.74-0.80). A SSA origin (2.97 [1.11-7.95]), malaise and fatigue (5.48 (1.13-26.63) and high-grade eosinophilia, (1.53, [0.86-2.71]) were predictors for schistosomiasis (AUC: 0.74 [0.70-0.77]; whereas SSA origin (5.68 [3.04-10.59]), itching symptom (5.05 [1.32-19.36], and high-grade eosinophilia (2.42, [1.33-4.41]) were predictors for strongyloidiasis (AUC: 0.73 [0.69-0.76]).

CONCLUSIONS

A stay in an endemic region, specifically SSA, having high-grade eosinophilia, and malaise and fatigue were the most important predictors for helminthiasis. Itching was an additional predictor for strongyloidiasis.

Postmarketing Analysis of Eosinophilic Adverse Reactions in the use of Biologic Therapies for Type 2 Inflammatory Conditions

BACKGROUND

Temporary eosinophilia is a potential adverse reaction of monoclonal antibody therapies in the treatment of a variety of type 2 inflammatory conditions, including asthma and chronic rhinosinusitis with nasal polyposis (CRSwNP). The pathophysiology, epidemiology, and clinical significance of eosinophilia and eosinophilic adverse reactions following the initiation of biologic therapy are unclear.

OBJECTIVES

To describe the postmarketing, eosinophilic adverse reactions with clinical significance in patients treated with the 3 biologic therapies approved by the U.S. Food and Drug Administration (FDA) for CRSwNP: dupilumab, omalizumab, and mepolizumab.

METHODS

The FDA Adverse Event Reporting System (FAERS) Public Dashboard was searched for eosinophilic adverse reactions related to dupilumab, omalizumab, and mepolizumab treatments from November 2004 to December 2022. Data regarding each of the eosinophilic adverse reactions were extracted and analyzed.

RESULTS

A total of 218, 270, and 134 reports of eosinophilic adverse reactions were reported among patients who were treated with dupilumab, omalizumab, and mepolizumab, respectively. The most common eosinophilic adverse reaction was eosinophilic granulomatosis with polyangiitis (338 patients), followed by eosinophilic respiratory tract reactions (158 patients). The most common indication for biological treatment among the reaction groups was asthma.

CONCLUSIONS

Eosinophilic adverse reactions are rare but consequential complications of biological treatment. They are more common among patients treated for asthma and chronic rhinosinusitis with nasal polyposis. Measuring and monitoring blood eosinophil levels may be appropriate in specific clinical instances when patients are started on different biologic therapies for type 2 inflammatory conditions.

Moderate-High Blood Eosinophilia Is Associated with Increased Hospitalization and Other Asthma Comorbidities

(1) Background: Eosinophilia has traditionally been linked to eosinophilic asthma, for which it is the gold-standard prognostic biomarker. However, the association between eosinophilia and the presence of other diseases and comorbidities is yet unclear. (2) Methods: For this retrospective study, we reviewed the electronic medical records of 49,909 subjects with blood eosinophilia to gather data on the presence of asthma, COPD, sleep apnea, tuberculosis, dyslipidemia, hypertension, and other cardiovascular diseases and severe CRSwNP among these subjects. Demographic features including age, sex, and smoking habits were collected, as well as the number of hospitalizations and emergency department visits. T-tests, ANOVA, Fisher test, and logistic regression models were used. (3) Results: For all age groups studied, eosinophilia was significantly more prevalent among asthmatic subjects than nonasthmatics, especially in patients also presenting CRSwNP, hypertension, and dyslipidemia. The likelihood of developing asthma, COPD, and CRSwNP, and hospitalization, was increased when BEC was above 600 eosinophils/μL. The association between asthma, CRSwNP, and BEC was corroborated by multiple logistic regressions models. (4) Conclusions: We demonstrated the association of having over 600 blood eosinophils/μL with a higher number of hospitalizations and comorbidities (CRSwNP and COPD), which proves that BEC is a highly useful parameter to consider in subjects who present blood eosinophilia.

Case Report: Hypereosinophilic syndrome vs. patent foramen ovale as etiopathogenetic contributors to stroke

Hypereosinophilic syndrome (HES), characterized by an increased number of eosinophils in tissues and/or blood, presents with heterogeneous clinical manifestations. Studies have shown that HES can affect the nervous system and may be associated with cerebral infarction. Patent foramen ovale (PFO) is the most common congenital intracardiac defect that can cause right-to-left shunting and contribute to the paradoxical embolization of venous emboli, and even lead to stroke. We report the case of a young man who presented with cerebral infarction accompanied by both HES and PFO. The patient underwent thorough evaluation to determine the source of emboli and the potential pathogenesis. In this case, HES was confirmed and glucocorticoid treatment was conducted. Direct imaging using optical coherence tomography (OCT) confirmed that the embolus originated from the PFO. Therefore, we performed PFO occlusion. The patient recovered well, and no new cerebral infarction was observed at 6-month follow-up. Based on the results of our study, we conclude that it is important to consider unusual etiologies of cerebral infarction, particularly in younger patients.

Hypereosinophilic syndrome presenting as eosinophilic gastroenteritis exacerbated by clopidogrel bisulphate

Clopidogrel is a widely prescribed prodrug with antithrombotic activity that functions by irreversibly inhibiting the P2Y12 receptors on platelets; nevertheless, drug-induced eosinophilia from this drug is rarely reported. An 81-year-old man was diagnosed with cerebral infarction 2 months earlier and was admitted to our hospital with rash, fever, wheezing, and stomach discomfort after being initiated with clopidogrel treatment. Based on his medical history, chest CT, and gastroscopy, we diagnosed him with clopidogrel-induced hypereosinophilic syndrome. After discontinuation of clopidogrel, the eosinophilia and symptoms improved. In cases of drug-induced eosinophilia, it is important to obtain a detailed medical history.

The multidisciplinary approach to eosinophilia

Eosinophilic granulocytes are normally present in low numbers in the bloodstream. Patients with an increased number of eosinophilic granulocytes in the differential count (eosinophilia) are common and can pose a clinical challenge because conditions with eosinophilia occur in all medical specialties. The diagnostic approach must be guided by a thorough medical history, supported by specific tests to guide individualized treatment. Neoplastic (primary) eosinophilia is identified by one of several unique acquired genetic causes. In contrast, reactive (secondary) eosinophilia is associated with a cytokine stimulus in a specific disease, while idiopathic eosinophilia is a diagnosis by exclusion. Rational treatment is disease-directed in secondary cases and has paved the way for targeted treatment against the driver in primary eosinophilia, whereas idiopathic cases are treated as needed by principles in eosinophilia originating from clonal drivers. The vast majority of patients are diagnosed with secondary eosinophilia and are managed by the relevant specialty-e.g., rheumatology, allergy, dermatology, gastroenterology, pulmonary medicine, hematology, or infectious disease. The overlap in symptoms and the risk of irreversible organ involvement in eosinophilia, irrespective of the cause, warrants that patients without a diagnostic clarification or who do not respond to adequate treatment should be referred to a multidisciplinary function anchored in a hematology department for evaluation. This review presents the pathophysiology, manifestations, differential diagnosis, diagnostic workup, and management of (adult) patients with eosinophilia. The purpose is to place eosinophilia in a clinical context, and therefore justify and inspire the establishment of a multidisciplinary team of experts from diagnostic and clinical specialties at the regional level to support the second opinion. The target patient population requires highly specialized laboratory analysis and therapy and occasionally has severe eosinophil-induced organ dysfunction. An added value of a centralized, clinical function is to serve as a platform for education and research to further improve the management of patients with eosinophilia. Primary and idiopathic eosinophilia are key topics in the review, which also address current research and discusses outstanding issues in the field.

Pediatric Eosinophilia: A Review and Multiyear Investigation into Etiologies

OBJECTIVES

To identify the etiology of peripheral eosinophilia in a large pediatric population and to develop a diagnostic algorithm to help guide diagnosis and management of peripheral eosinophilia in the outpatient pediatric population.

STUDY DESIGN

We performed a retrospective chart review of children presenting to Texas Children's Hospital in Houston with peripheral eosinophilia between January 1, 2011 and December 31, 2019. Eosinophilia was classified as mild (absolute eosinophil count [AEC] >500 and <1500 cells/μL), moderate (AEC >1500 and <4500 cells/μL), or severe (AEC >4500 cells/μL). Demographic information and diagnostic workup data were collected.

RESULTS

A total of 771 patients aged <18 years were evaluated. The most common cause of eosinophilia was allergy (n = 357; 46%), with atopy (n = 296) and drug reaction (n = 54) the most common subcauses. This was followed by unknown etiology (n = 274; 36%), infectious causes (n = 72; 9%), and eosinophilic disorders (n = 47; 6%). Many patients with an unknown cause (n = 202; 74%) had limited or no follow-up testing.

CONCLUSIONS

More information on the etiology of pediatric eosinophilia and workup data could help identify the causes. This study provides important information on the evaluation of eosinophilia in the US pediatric population, including a diagnostic algorithm to guide primary care pediatricians.

Proposed refined diagnostic criteria and classification of eosinophil disorders and related syndromes

Eosinophilia and eosinophil activation are recurrent features in various reactive states and certain hematologic malignancies. In patients with hypereosinophilia (HE), HE-induced organ damage is often encountered and may lead to the diagnosis of a hypereosinophilic syndrome (HES). A number of known mechanisms and etiologies contribute to the development of HE and HES. Based on these etiologies and the origin of eosinophils, HE and HES are divided into primary forms where eosinophils are clonal cells, reactive forms where an underlying reactive or neoplastic condition is detected and eosinophils are considered to be "non-clonal" cells, and idiopathic HE and HES in which neither a clonal nor a reactive underlying pathology is detected. Since 2012, this classification and the related criteria have been widely accepted and regarded as standard. However, during the past few years, new developments in the field and an increasing number of markers and targets have created a need to update these criteria and the classification of HE and HES. To address this challenge, a Working Conference on eosinophil disorders was organized in 2021. In this conference, a panel of experts representing the relevant fields, including allergy, dermatology, hematology, immunology, laboratory medicine, and pathology, met and discussed new markers and concepts as well as refinements in definitions, criteria and classifications of HE and HES. The outcomes of this conference are presented in this article and should assist in the diagnosis and management of patients with HE and HES in daily practice and in the preparation and conduct of clinical trials.

Recent advances of eosinophils and its correlated diseases

Eosinophils are differentiated by bone marrow multipotent progenitor cells and are further released into peripheral blood after maturation. Human eosinophils can exhibit unique multi-leaf nuclear morphology, which are filled with cytoplasmic granules that contain cytotoxicity and immune regulatory proteins. In recent years, many studies focused on the origin, differentiation and development process of eosinophils. It has been discovered that the eosinophils have the regulatory functions of innate and adaptive immunity, and can also function in several diseases, including asthma, chronic obstructive pulmonary diseases, acute respiratory distress syndrome, malignant tumors and so on. Hence, the role and effects of eosinophils in various diseases are emphasized. In this review, we comprehensively summarized the development and differentiation process of eosinophils, the research progress of their related cytokines, diseases and current clinical treatment options, and discussed the potential drug target, aiming to provide a theoretical and practical basis for the clinical prevention and treatment of eosinophil-related diseases, especially respiratory diseases. To conclude, the guiding significance of future disease treatment is proposed based on the recent updated understandings into the cell functions of eosinophils.

Characteristics of Dermatological Patients With Blood Eosinophilia: A Retrospective Analysis of 453 Patients

BACKGROUND

Skin diseases associated with blood or tissue eosinophilia are common. Because these have various clinical manifestations, making the correct diagnosis can be challenging. So far, dermatological patients with concomitant blood eosinophilia have not been characterized.

OBJECTIVE

To investigate patterns of dermatological patients with concomitant blood eosinophilia to obtain information helpful for optimizing disease management.

METHODS

In this retrospective study, demographic and clinical data and diagnostic test results of all patients presenting with dermatoses associated with blood eosinophilia referred to a university center from 2014 to 2018 were extracted from the electronic patient charts and evaluated using descriptive and semantic map analyses.

RESULTS

A total of 453 patients (51.4% females; mean age, 58.4 ± 21.7 years) were included and grouped according to blood absolute eosinophil counts: severe, greater than or equal to 1.5 G/L (n = 87; 19.2%); moderate, 1.0 to 1.49 G/L (n = 73; 16.1%); and mild eosinophilia, 0.5 to 0.99 G/L (n = 293; 64.7%). Most patients presented with chronic (64.6%), generalized skin lesions (75.9%), and pruritus (88.1%). Statistical analyses revealed 3 distinct patterns: (1) mild eosinophilia associated with localized skin disease, age less than 50 years, history of atopy, and diagnosis of eczema or infectious disease; (2) moderate eosinophilia linked to generalized skin lesions, pruritus, age more than 70 years, and autoimmune bullous disease; and (3) severe eosinophilia associated with diagnosis of hypereosinophilic syndromes, drug hypersensitivity, or malignant disease.

CONCLUSIONS

Based on the pattern analysis of patients with dermatoses associated with blood eosinophilia, a diagnostic workup has been developed aiming at setting the correct differential diagnosis in a feasible and effective manner.

The emerging roles of eosinophils: Implications for the targeted treatment of eosinophilic-associated inflammatory conditions

Eosinophils have multiple relevant biological functions, including the maintenance of homeostasis, host defense against infectious agents, innate immunity activities, immune regulation through Th1/Th2 balance, anti-inflammatory, and anti-tumorigenic effects. Eosinophils also have a main role in tissue damage through eosinophil-derived cytotoxic mediators that are involved in eosinophilic inflammation, as documented in Th2-high asthma and other eosinophilic-associated inflammatory conditions.

Recent evidence shows that these multiple and apparently conflicting functions may be attributed to the existence of different eosinophil subtypes (i.e.: tissue resident and inducible eosinophils). Therapeutic intervention with biological agents that totally deplete tissues and circulating eosinophils or, vice versa, maintain a minimal proportion of eosinophils, particularly the tissue-resident ones, could therefore have a very different impact on patients, especially when considering the administration of these therapies for prolonged time. In addition, the characterization of the predominant pathway underlying eosinophilic inflammation by surrogate biomarkers (circulating eosinophils, organ-specific eosinophils levels such as eosinophil count in sputum, bronchoalveolar lavage, tissue biopsy; total circulating IgE levels, or the use of FeNO) in the single patient with an eosinophilic-associated inflammatory condition could help in choosing the treatment.

These observations are crucial in light of the increasing therapeutic armamentarium effective in modulating eosinophilic inflammation through the inhibition in different, yet complementary ways of eosinophil pathways, such as the interleukin-5 one (with mepolizumab, benralizumab, reslizumab) or the interleukin-4/13 one (with dupilumab and lebrikizumab), in severe T2-high asthma as well as in other systemic eosinophilic associated diseases, such as eosinophilic granulomatosis with polyangiitis and hypereosinophilic syndrome.

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Recent evidence pointed out the existence of different eosinophil subtypes, i.e. tissue resident and inducible eosinophils, with different and apparently conflicting functions.

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Biological therapies with different mechanisms can deplete completely tissues and circulating eosinophils or maintain a minimal proportion of eosinophils, particularly the tissue-resident ones, and this could therefore have a different impact on patients, especially when considering the administration of these therapies for prolonged time.

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The identification of the predominant pathway underlying eosinophilic inflammation by surrogate biomarkers (circulating eosinophils, organ-specific eosinophils levels such as eosinophil count in sputum, bronchoalveolar lavage, tissue biopsy; total circulating IgE levels, or the use of FeNO) should be sought in the single patient with an eosinophilic-associated inflammatory condition.

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These considerations may help in choosing the best anti-eosinophilic treatment, considering the increasing therapeutic armamentarium effective in modulating eosinophilic inflammation through the inhibition of the interleukin-5 one (with mepolizumab, benralizumab, reslizumab) or the interleukin-4/13 one (with dupilumab and lebrikizumab)

Immune Dysregulation in IgG4-Related Disease

Immunoglobin G₄-related disease (IgG₄-RD) is one of the newly discovered autoimmune diseases characterized by elevated serum IgG₄ concentrations and multi-organ fibrosis. Despite considerable research and recent advances in the identification of underlying immunological processes, the etiology of this disease is still not clear. Adaptive immune cells, including different types of T and B cells, and cytokines secreted by these cells play a vital role in the pathogenesis of IgG₄-RD. Antigen-presenting cells are stimulated by pathogens and, thus, contribute to the activation of naïve T cells and differentiation of different T cell subtypes, including helper T cells (Th1 and Th2), regulatory T cells, and T follicular helper cells. B cells are activated and transformed to plasma cells by T cell-secreted cytokines. Moreover, macrophages, and some important factors (TGF-β, etc.) promote target organ fibrosis. Understanding the role of these cells and cytokines implicated in the pathogenesis of IgG₄-RD will aid in developing strategies for future disease treatment and drug development. Here, we review the most recent insights on IgG₄-RD, focusing on immune dysregulation involved in the pathogenesis of this autoimmune condition.

The causes of a peripheral blood eosinophilia in a secondary care setting

BACKGROUND

A peripheral blood eosinophilia of greater than 1.0 × 10⁹ /L is relatively unusual and offers a clue to the underlying diagnosis. In 2003, we established a specialist service to diagnose unexplained eosinophilia.

OBJECTIVE

To describe the causes of an eosinophilia in our service and the diagnostic algorithm we developed.

METHODS

Subjects were referred by physician colleagues across a range of specialties and undertook standard investigations following a semi-structured protocol. Data were extracted from a bespoke database.

RESULTS

Three hundred and eighty two subjects were referred over a 17-year period. Average age was 54 years and 183 (48%) of subjects were female, with 21 of 25 (84%) females in the idiopathic eosinophilic pneumonia group (p < 0001), 22 of 30 (73%) females in the gastrointestinal disease group (p < .008), but 11 of 37 (30%) females in the eosinophilic granulomatosis with polyangiitis group (p < .04). A diagnosis was assigned after systematic evaluation using a pre-defined algorithm in 361 (94.5%) of cases. Fungal allergy (82 subjects: 21%), parasitic infection (61 subjects: 16%) and severe eosinophilic asthma (50 subjects: 13%) were the three commonest individual diagnoses. Hypereosinophilic syndrome (HES) disease including eosinophilic granulomatosis with polyangiitis (EGPA) accounted for 85 subjects (20%) of which seven subjects (2%) had myeloproliferative disease (M-HES). A high IgE was common, and 79 (91%) of subjects with complete data who had an IgE of ≥1000 IU/L had fungal allergy or parasite infection. The serum tryptase was raised in 44 of 302 (14.5%) of individuals across all diagnostic groups, though none had mastocytosis.

CONCLUSION

A diagnosis of an unexplained eosinophilia can usually be determined using as semi-structured algorithm. Parasitic infection and fungal allergy often with severe eosinophilic asthma were common causes, whereas HES, particularly myeloproliferative, disease was relatively rare.

Physiology and pathology of eosinophils: Recent developments: Summary of the Focus Workshop Organized by DGAKI

Over the last century, eosinophils have been regarded ambiguously either as 'friends' or 'foes'. Recent developments have greatly enhanced our understanding of the role and function of eosinophils in health and disease. Pathogenic eosinophilic inflammation can lead to severe diseases in various organs, such as the gastrointestinal tract, airways, heart and skin. In a 2-day focus workshop of the German Society for Allergology and Clinical Immunology (DGAKI), the state of the art was discussed and practical recommendations for diagnosis and treatment of eosinophilic diseases, with a particular focus on new biologics, such as anti-interleukin 5 and anti-interleukin 5R, were derived.

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.

Peripheral Blood Eosinophils and Nine Years Mortality in COPD Patients

BACKGROUND

Eosinophil counts increase during chronic obstructive pulmonary disease (COPD) exacerbation and influence the response to different agents (such as inhaled and systemic corticosteroids), as well as increase the production of other inflammatory cytokines. However, few studies have evaluated the association between peripheral blood eosinophils with mortality rate.

OBJECTIVE

To evaluate the association between peripheral blood eosinophils and mortality rate in COPD patients over a nine-year period.

STUDY DESIGN AND METHODS

This cohort included 133 COPD patients assessed at baseline by spirometry, pulse oximetry (SpO2), complete blood count, body composition, dyspnea intensity [Modified Medical Research Council (mMRC)] and the six-minute distance test (6MWD). The Kaplan-Meier curve followed by a Log rank test was used to evaluate mortality rate related to eosinophil cutoff point categorization. Multivariate Cox regression analysis was performed to identify the association between eosinophils and mortality with all subjects evaluated at baseline, adjusted for age, gender, mMRC, 6MWT, forced expiratory volume in the first second (FEV1) and SpO2.

RESULTS

Nineteen patients did not complete follow-up and it was not possible to identify the date of death in four others. Therefore, 110 patients were included in the analysis. At baseline, 81% presented ≥150 eosinophil cells and 72% presented ≥2%. We identified a three-fold higher risk of death in those with <2% eosinophils and <150 cells. We did not identify statistical differences when using other cutoff points.

CONCLUSION

The decrease in number of peripheral eosinophils, with cutoff points at 2% and 150 cells, may be associated with a higher risk of death in COPD patients over nine years.

Idiopathic Hypereosinophilic Syndrome with Multiple Organ Involvement

Idiopathic hypereosinophilic syndrome is a rare disease which is diagnosed after excluding other conditions. The syndrome is characterized by multiple organ involvement including the heart, nervous system, lungs, and gastrointestinal tract. The disease is suspected if there is peripheral blood eosinophilia and no clear etiology. The main treatment is corticosteroids. Patients who do not respond to corticosteroids can be treated with imatinib, immunomodulatory agents, myelosuppressive therapy, or mepolizumab. Alemtuzumab can be considered in severe cases that are unresponsive to other therapies. In this paper, we describe a case of idiopathic hypereosinophilic syndrome with mainly cardiac system involvement and left ventricular thrombus formation which was complicated by cerebral thromboemboli while on warfarin with international normalized ratio in the therapeutic range. Our patient responded well to steroids appreciated by improvement in clinical symptoms and decrease in eosinophil count.

Association of antipsychotic use with raised eosinophil count

The current study aimed to assess the possibility of an association between first and second generation antipsychotic medication and raised eosinophil count. A total of 22 in-patients at the psychiatric unit of the University General Hospital ‘Attikon’, a tertiary hospital, were included in the present study. Patients had received antipsychotic monotherapy and did not have any co-morbidities or require additional treatments. Patients were monitored weekly and their eosinophil count was assessed. One-way ANOVA and summary measures analysis were applied to study the effect of time and medication type on the absolute eosinophil concentration (or relative percentage) for each patient. The differences in mean eosinophil concentrations or relative percentage by patient and time were also assessed. An increase in the absolute concentration and the relative percentage of eosinophils over time was observed in patients receiving Olanzapine, Haloperidol and Aripiprazole. However, there was no difference between individual medications. In conclusion, antipsychotics may be associated with increased eosinophil count over time; however, larger studies involving more patients and a longer follow-up are required to reach a definitive conclusion.

Twist1 sustains the apoptosis resistance in eosinophils in nasal mucosa of allergic rhinitis

Eosinophils (Eos) are the canonical effector cells in allergic rhinitis (AR) and many inflammatory diseases. The mechanism of eosinophilia occurring in the lesion sites is not fully understood yet. Twist1 protein (Twist, in short) is an apoptosis inhibitor that also has immune regulatory functions. This study aims to investigate the role of Twist in the pathogenesis of eosinophilia in AR. In this study, surgically removed human nasal mucosal samples were obtained from patients with chronic sinusitis and nasal polyps with AR (the AR group) or without AR (the nAR group). Eos were isolated from the samples by flow cytometry. We found that abundant Eos were obtained from the surgically removed nasal mucosa tissues of both nAR and AR groups. Significantly higher Ras activation was detected in AR Eos than that in nAR Eos. Ras activation was associated with the apoptosis resistance in AR Eos. The Twist (an apoptosis inhibitor) expression was higher in AR Eos, which was positively correlated with the Ras activation status. The sensitization to IgG induced Twist expression in Eos, in which Ras activated the MAPK-HIF-1α pathway, the latter promoted the Twist gene transcription. Twist bound Rac GTPase activating protein-1 to sustain the Ras activation in Eos. Ras activation sustained the apoptosis resistance in Eos. In conclusion, high Ras activation was detected in the AR nasal mucosal tissue-isolated Eos. IgG-sensitization induced Ras activation and Twist expression in Eos, that conferred Eos the apoptosis resistance.

Successful Long-Term Control of the Syndrome of Episodic Angioedema With Eosinophilia (Gleich Syndrome) With Low-Dose Imatinib Mesylate and Prednisone

The syndrome of episodic angioedema with eosinophilia, first reported over 40 years ago, is a hypereosinophilic disorder that, uniquely, is not associated with end-organ pathology. However, patients develop a constellation of symptoms that include angioedema, urticaria, fatigue, and fever. Episodes are accompanied by massive hypereosinophilia and weight gain. Type II serum cytokine levels (IL-5, IL-13, IL-9, and IL-10) show cyclic variations peaking at or just prior to the peak of eosinophilia and an abnormal Th2 cell phenotype has been reported. Attacks may occur with predictable regularity and have been described in both adults and children. Glucocorticoid therapy reliably reverses symptoms with accompanying diuresis, defervesce, and normalization of the eosinophil count. In this report, a patient who had the syndrome of episodic angioedema with eosinophilia exceeding 20 years is reported. He has had no end-organ damage to date. Testing for the CHIC2 deletion, a surrogate for the FIP1L1-PDGFRA fusion, was negative. Use of imatinib mesylate, initially as a steroid-sparing agent, and subsequently as a maintenance medication, plus low-dose prednisone has provided long-term control of hypereosinophilia and all clinical manifestations.

Extensive eye-oral-bronchial mucosal nodules with eosinopgillia: a rare case report and literature review

BACKGROUND

Mucosal nodules can be caused by infection, inflammation and neoplastic disease. Many noninfectious diseases, such as eosinophilia, amyloidosis, sarcoidosis, Wegener's granuloma, langerhans cell histiocytosis etc., are associated with the formation of multisytem mucosal nodules, especially significant bronchial lesions. Detailed medical history, comprehensive metabolic profile, biopsy specimen and imaging examinations are required for differentiating among these disorders. The process of diagnosis and treatment of our patient's mucosal nodules was challenging, which could be helpful to similar cases.

CASE PRESENTATION

We represent a case of a 29-year-old woman with plentiful nodules of unknown origin on extensive mucous membranes. Biopsy specimen reports inflammatory lesions with large numbers of neutrophils, lymphocytes, and varying degrees of eosinophils. Treatment of anti-infection, anti-tussive and anti-allergic was ineffective, but glucocorticoid showed great improvement to her symptoms.

CONCLUSION

We experienced a rare case with plentiful nodules of unknown origin on extensive mucous membranes. She may be a specific phenotype of eosinophilia or may be a novel multisystem disease with respiratory system as the primary symptom. The diagnosis of our patient remains unclear, but tentative glucocorticoid therapy was beneficial.

Blood Eosinophil Count and Hospital Readmission in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Purpose

This retrospective, observational cohort study investigated the association of blood eosinophil counts within 1 week of hospitalization for acute exacerbation of COPD (AECOPD) with subsequent risk of all-cause and COPD-related readmission from a large integrated health system.

Patients and Methods

Electronic medical records were extracted for index hospitalization for AECOPD at all Intermountain Healthcare hospitals. The primary outcome was the relationship of blood eosinophil count to 30-day all-cause readmission; secondary outcomes were 60-day, 90-day, and 12-month all-cause readmission, COPD-related readmission, and empiric derivation of the eosinophil count with the highest area under the curve (AUC) for predicting 30-day all-cause readmission.

Results

Of 2445 included patients, 1935 (79%) had a blood eosinophil count <300 cells/µL and 510 (21%) had a count ≥300 cells/µL. Using a 300-cells/μL threshold, there was no significant difference between high and low eosinophil groups in 30-day (odds ratio [OR]=1.05, 95% confidence interval [CI]=0.75–1.47) or 60-day (OR=1.15, 95% CI=0.88–1.51) all-cause readmissions. However, patients with greater (versus lesser) eosinophil counts had increased 90-day and 12-month all-cause readmissions (OR=1.35, 95% CI=1.06–1.72, and OR=1.32, 95% CI=1.07–1.62). COPD-related readmission rates were significantly greater for patients with greater (versus lesser) eosinophil counts at 30, 60, and 90 days and 12 months (OR range=1.52–1.97). A total of 70 cells/µL had the most discriminatory power to predict 30-day all-cause readmission (highest AUC).

Conclusion

Eosinophil counts in patients with COPD were not associated with a difference in 30-day all-cause readmissions. However, greater eosinophil counts were associated with increased risk of all-cause readmission at 90 days and 12 months and COPD-related readmission at 30, 60, and 90 days and 12 months. Patients with eosinophils <70 cells/μL had the lowest risk for 30-day all-cause readmission. Blood eosinophils in patients hospitalized with AECOPD may be a useful biomarker for the risk of hospital readmission.

Inhibition of Bcl2L12 Attenuates Eosinophilia-Related Inflammation in the Heart

Background: The eosinophilic inflammation plays a critical role in myocarditis (Mcd); its underlying mechanism remains to be further elucidated. This study aims to investigate the role of Bcl2-like protein 12 (Bcl2L12) in inducing the defects of apoptosis in eosinophils (Eos) of the heart tissues.

Methods: Human explant heart samples were collected. Eosinophilia and myocarditis (Mcd)-like inflammation were induced in the mouse heart by immunizing with murine cardiac α-myosin heavy chain (MyHCα) peptides.

Results: Markedly more Eos were observed in heart tissues from patients with Mcd than those from patients with dilated cardiomyopathy. Eos isolated from Mcd hearts showed the signs of apoptosis defects. The Eo counts in the Mcd heart tissues were positively correlated with the Bcl2L12 expression in Eos isolated from the heart tissues. Exposure to interleukin 5 in the culture induced the expression of Bcl2L12 in Eos. Bcl2L12 bound c-Myc, the transcription factor of Fas ligand (FasL), to prevent c-Myc from binding to the FasL promoter, to restrict the FasL gene transcription in Eos. Inhibition of Bcl2L12 prevented the induction of eosinophilia and Mcd-like inflammation in the mouse heart.

Conclusions: The Bcl2L12 expression contributes to apoptosis defects in Eos of the Mcd heart. Blocking Bcl2L12 prevents the eosinophilia induction and alleviates Mcd-like inflammation in mice.

Infection by Strongyloides stercoralis in immigrants with Chagas disease: evaluation of eosinophilia as screening method in primary care

OBJECTIVES

To evaluate co-infection of Strongyloides stercoralis and Trypanosoma cruzi and to assess eosinophilia as a screening test for the detection of S. stercoralis infection in patients with Chagas disease (CD).

METHODS

A retrospective diagnostic validation study was performed on serum samples from primary care patients diagnosed with CD in the southern Barcelona metropolitan area. All samples with eosinophilia (n = 87) and a random sample of non-eosinophilic sera (n = 180) were selected. Diagnosis of CD was based on positive serology by means of two tests: ORTHO® T. cruzi ELISA test, and BIO-FLASH® Chagas or Bioelisa CHAGAS. SCIMEDX ELISA STRONGY-96 was used to diagnose strongyloidiasis.

RESULTS

Strongyloides stercoralis serology was positive in 15% of patients of whom 95% showed eosinophilia, vs. 21% of those with negative serology (P < 0.001), with differences in the mean eosinophil count (0.49 vs. 0.27 × 10⁹ /l). Only 1.1% of patients with CD but without eosinophilia presented positive serology for S. stercoralis, whereas 44% of patients with CD and eosinophilia did (P < 0.001). Sensitivity and specificity values for eosinophilia were thus 95% and 79%, respectively. PPV was 42.5% and NPV, 98.9%.

CONCLUSIONS

The prevalence of co-infection by T. cruzi and S. stercoralis is not negligible and has probably been underestimated for years in many areas, due to frequently subclinical infections. Therefore, serology seems mandatory for these patients and the use of eosinophilia as initial screening could facilitate the task, decreasing the number of analyses to be performed.

Peptides of major basic protein and eosinophil cationic protein activate human mast cells

The eosinophil granule proteins, major basic protein (MBP) and eosinophil cationic protein (ECP), activate mast cells during inflammation; however the mechanism responsible for this activity is poorly understood. We found that some theoretical tryptase-digested fragments of MBP and ECP induced degranulation of human cord blood-derived mast cells (HCMCs). The spectrum of activities of these peptides in HCMCs coincided with intracellular Ca²⁺ mobilization activities in Mas-related G-protein coupled receptor family member X2 (MRGPRX2)-expressing HEK293 cells. Two peptides corresponding to MBP residues 99–110 (MBP (99–110)) and ECP residues 29–45 (ECP (29–45)), respectively, induced degranulation of HCMCs and intracellular Ca²⁺ mobilization in MRGPRX2-expressing HEK293 cells in a concentration-dependent manner. Stimulation with MBP (99–110) or ECP (29–45) induced the production of prostaglandin D2 by HCMCs. The activities of MBP (99–110) and ECP (29–45) in both HCMCs and MRGPRX2-expressing HEK293 cells were inhibited by MRGPRX2-specific antagonists. In conclusion, these results indicated that MBP and ECP fragments activate HCMCs, and it may occur via MRGPRX2. Our findings suggest that tryptase-digested fragments of eosinophil cationic proteins acting via the MRGPRX2 pathway may further our understanding of mast cell/eosinophil communication.

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Mast cell activators were found in tryptase-fragments from MBP and ECP.

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These fragments activated MRGPRX2-expressing cells.

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MRGPRX2 antagonists inhibited mast cell activation caused by active fragments.

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Active fragments may work as mediators in mast cell/eosinophil communication.

Different clinical patterns of IgG4-RD patients with and without eosinophilia

It has been reported that patients with IgG4-related disease (IgG4-RD) showed an elevated incidence of eosinophilia. We aim to explore the clinical patterns of IgG4-RD patients with and without eosinophilia. Four hundred and twenty-five IgG4-RD patients referred to Peking Union Medical College Hospital were enrolled. Blood eosinophil count higher than 0.5 × 10⁹/L was defined as eosinophilia. Clinical features of all the participants were collected and analyzed statistically. Eighty-seven patients (20%) with eosinophilia were found. As compared to those with a normal range of blood eosinophil count, male predominance, longer disease duration, increased prevalence of dacryoadenitis, sialadenitis, lymphadenopathy, and skin rash, higher IgG4-RD responder index, more organ involvement and higher levels of serum IgG4 (17.0 g/L vs 6.5 g/L, P < 0.001) was found in patients with eosinophilia. There was no significant difference in the incidence of allergic disease between the two groups. Peripheral eosinophil counts were positively correlated with disease duration, the number of involved organs, IgG4-RD responder index, and serum IgG4. Higher recurrence rate during follow-up period was found in patients with eosinophilia [28.6% (20/70) vs 17.1% (42/245), P = 0.034]. IgG4-RD patients with eosinophilia exhibited different clinical patterns from patients without. Eosinophilia appeared independent of allergies in IgG4-RD.

[Eosinophilic inflammation in chronic obstructive pulmonary disease]

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease that combines various clinical manifestations and pathophysiological mechanisms. It underlies the separation of patients with COPD by phenotypes, endotypes and a personalized therapy of this disease. The implementation of this approach is possible only with the use of appropriate biomarkers. One of the most important biomarkers of COPD is eosinophilia of blood and/or sputum, which is considered as a predictor of frequent exacerbations and the effectiveness of inhaled glucocorticosteroids in patients with COPD. The literature discusses the impact of eosinophilic inflammation on the prognosis, clinical and functional parameters in COPD, and the role of the targeted therapy in the treatment of eosinophilic COPD.

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.

Consultation for Elevated Blood Eosinophils: Clinical Presentations, High Value Diagnostic Tests, and Treatment Options

The workup of a patient found to have eosinophilia should follow a thorough path with a detailed history and physical examination aimed at eliciting eosinophilic organ involvement, followed by histological confirmation whenever possible. The differential diagnosis of hypereosinophilia is extensive, but a rational approach beyond the history and physical examination including serologic, blood, and bone marrow cell analyses, genetic testing, and radiologic imaging can distinguish many of the causes. Often input from specialists (eg, hematology, dermatology, pulmonary, gastroenterology, and neurology) can help narrow down the possibilities and eventually result in a specific diagnosis. An accurate diagnosis is key to choosing the optimal treatment for a particular condition, and this is certainly true for eosinophilic disorders. Myeloid neoplasms that present with eosinophilia, for example, may respond to medicines that the allergist may be less accustomed to using, such as immunosuppressive agents and kinase inhibitors. Similarly, newly approved biologics that target IL-5 and eosinophils may provide new options for management. What follows is a case-based approach that helps to underscore key features of diagnosis, management, and follow-up when faced with a patient with a potential eosinophil-related disorder.

Metastatic Lung Adenocarcinoma Presenting with Hypereosinophilia

Lung cancer is one of the most common malignancies in both male and female patients. It is classified into small cell lung cancers and non-small cell lung cancers. Lung adenocarcinoma is a subtype of non-small cell lung cancer and accounts for the highest prevalence of lung cancer. Eosinophils are white blood cells (WBCs) that originate from the granulocytic lineage. Hypereosinophilia is a rare condition characterized by an absolute eosinophil count (AEC) of more than 1500 cells/µL. This is different from eosinophilia, which is defined as an absolute eosinophil count of more than 500 cells/µL. Hypereosinophilia is associated with several conditions, including allergic disorders, helminth infections, rheumatologic disorders, and hematologic malignancies. Paraneoplastic eosinophilia is a rare finding in solid malignancies. Herein, we report the case of a 55-year-old male who presented with shortness of breath and chest pain and whose workup showed metastatic lung adenocarcinoma associated with hypereosinophilia in the absence of a primary bone marrow disorder.

Diagnosis and Novel Approaches to the Treatment of Hypereosinophilic Syndromes

PURPOSE OF REVIEW

Hypereosinophilic syndrome (HES) is characterized by persistent hypereosinophilia associated with end-organ damage. As our understanding of the pathogenesis of various forms of HES broadens, so does our ability to tailor steroid-sparing therapies for each subtype. The purpose of this review is to summarize recent literature related to the etiology, diagnosis, and management of HES.

RECENT FINDINGS

Mutations involved in subsets of HES can guide the choice of tyrosine kinase inhibitors beyond just imatinib. Several biologics that target interleukin-5 or its receptor have shown beneficial and selective eosinophil-reducing effects in clinical trials for asthma and other disorders including HES. Early clinical data with emerging therapies such as dexpramipexole and anti-Siglec-8 antibody show promise, but need to be confirmed in randomized trials. Several new biologics and tyrosine kinase inhibitors have been shown to lower eosinophil numbers, but more randomized trials are needed to confirm efficacy in HES.

Eosinophil Development, Disease Involvement, and Therapeutic Suppression

Human eosinophils have characteristic morphologic features, including a bilobed nucleus and cytoplasmic granules filled with cytotoxic and immunoregulatory proteins that are packaged in a specific manner. Eosinophil production in the bone marrow is exquisitely regulated by timely expression of a repertoire of transcription factors that work together via collaborative and hierarchical interactions to direct eosinophil development. In addition, proper granule formation, which occurs in a spatially organized manner, is an intrinsic checkpoint that must be passed for proper eosinophil production to occur. In eosinophil-associated disorders, eosinophils and their progenitors can be recruited in large numbers into tissues where they can induce proinflammatory organ damage in response to local signals. Eosinophils are terminally differentiated and do not proliferate once they leave the bone marrow. The cytokine IL-5 specifically enhances eosinophil production and, along with other mediators, promotes eosinophil activation. Indeed, eosinophil depletion with anti-IL-5 or anti-IL-5Rα is now proven to be clinically beneficial for several eosinophilic disorders, most notably severe asthma, and several therapeutics targeting eosinophil viability and production are now in development. Significant progress has been made in our understanding of eosinophil development and the consequences of tissue eosinophilia. Future research efforts focused on basic eosinophil immunobiology and translational efforts to assist in the diagnosis, treatment selection, and resolution of eosinophil-associated disorders will likely be informative and clinically helpful.

Eosinophils and eosinophil-associated diseases: An update

The goal of this series is to offer a survey of the latest literature for clinicians and scientists alike, providing a list of important recent advances relevant to the broad field of allergy and immunology. This particular assignment was to cover the topic of eosinophils. In an attempt to highlight major ideas, themes, trends, and advances relevant to basic and clinical aspects of eosinophil biology, a search of articles published since 2015 in the Journal of Allergy and Clinical Immunology and other high-impact journals was performed. Articles were then reviewed and organized, and then key findings were summarized. Given space limitations, many outstanding articles could not be included, but the hope is that what follows provides a succinct overview of recently published work that has significantly added to our knowledge of eosinophils and eosinophil-associated diseases.

How I Diagnose Hypereosinophilic Syndromes

Hypereosinophilic syndromes are a group of disorders characterised by significant eosinophilia and organ damage. They have proven challenging to define, diagnose, and study for many years, due in part to their variable clinical presentations, the overlap between neoplastic and reactive eosinophilia, and the lack of a universal marker of eosinophil clonality. Herein, we give an overview of the term and discuss aetiology and our approach to diagnosis.

Transcription Factors in Eosinophil Development and As Therapeutic Targets

Dynamic gene expression is a major regulatory mechanism that directs hematopoietic cell fate and differentiation, including eosinophil lineage commitment and eosinophil differentiation. Though GATA-1 is well established as a critical transcription factor (TF) for eosinophil development, delineating the transcriptional networks that regulate eosinophil development at homeostasis and in inflammatory states is not complete. Yet, recent advances in molecular experimental tools using purified eosinophil developmental stages have led to identifying new regulators of gene expression during eosinophil development. Herein, recent studies that have provided new insight into the mechanisms of gene regulation during eosinophil lineage commitment and eosinophil differentiation are reviewed. A model is described wherein distinct classes of TFs work together via collaborative and hierarchical interactions to direct eosinophil development. In addition, the therapeutic potential for targeting TFs to regulate eosinophil production is discussed. Understanding how specific signals direct distinct patterns of gene expression required for the specialized functions of eosinophils will likely lead to new targets for therapeutic intervention.

Hypereosinophilic syndrome presenting with multiple organ infiltration and deep venous thrombosis: A case report and literature review

BACKGROUND

Hypereosinophilic syndrome (HES) can be fatal, particularly when eosinophils infiltrate vital organs and/or if extensive thrombosis develops. However there are no standard recommendations for the use of anticoagulant therapy of HES in the setting of thrombosis.

METHODS

We herein present a case of a 46-year-old female who presented with marked peripheral eosinophilia with symptoms of multi-organ infiltration and extensive deep venous thrombosis (DVT). In this case, evaluation was carried out before the diagnosis was established, and timely standard-dose corticosteroids combined with a new oral anticoagulant (NOAC) therapy were carried out.

RESULTS

These measures resulted in a rapid response and long-term disease control.

CONCLUSION

Although there are no data to support which anticoagulant is preferred in this setting, this case indicates that the new oral anticoagulants may play an important role in the treatment of thrombosis in HES.