Eosinophilic disorders: evaluation of current classification and diagnostic criteria, proposal of a practical diagnostic algorithm

Idiopathic hypereosinophilic syndromes and rare dysimmune conditions associated with hyper-eosinophilia in practice: An innovative multidisciplinary approach

Hypereosinophilic syndromes (HES) represent a group of rare dis-immune conditions characterized by blood hyper-eosinophilia and eosinophilic related burden. Especially the idiopathic subtype (I-HES) is particularly difficult to diagnose because of its heterogeneous clinical presentation, the lack of specific findings on physical exam, lab tools, and imaging informative enough to unequivocally confirm the diagnosis and the overlap with other entities, including eosinophilic organ-diseases or systemic dis-immune conditions other than I-HES (from atopy to eosinophilic granulomatosis with polyangiitis [EGPA], the last often extremely difficult to distinguish from HES). Taken together, all the features mentioned above account for an extremely difficult early recognition HES and on-time referral to a specialized centre. The referral itself is challenging due to a not univocal specialist identification, because of the variability of physicians managing HES in different settings (including allergist/clinical immunologist, haematologist, internal medicine doctors, pulmonologist, rheumatologist). Furthermore, the approach in terms of personalized treatment identification and follow-up plan (timing, organ assessment), is poorly standardized. Further translational and clinical research is needed to address the mentioned unmet needs, but on practical grounds increasing the overall clinicians' awareness on HES and implementing healthcare pathways for HES patients represent a roadmap that every clinician might try to realize in his specific setting. The present review aims at providing an overview about the current challenges and unmet needs in the practical approach to HES and rare hypereosinophilic allergo-immunological diseases, including a proposal for an innovative multidisciplinary organizational model.

Eosinophil-derived extracellular vesicles: isolation and classification techniques and implications for disease pathophysiology

Eosinophils are leukocytes characterized by their ability to release granule content that is highly rich in enzymes and proteins. Besides the antihelminthic, bactericidal, and antiviral properties of eosinophils and their secretory granules, these also play a prominent role in the pathophysiology of diseases such as asthma, eosinophilic esophagitis, and other hypereosinophilic conditions by causing tissue damage and airway hyperresponsiveness. Although this cell was first recognized mainly for its capacity to release granule content, nowadays other capabilities such as cytokine secretion have been linked to its physiology, and research has found that eosinophils are not only involved in innate immunity, but also as orchestrators of immune responses. Nearly 10 yr ago, eosinophil-derived extracellular vesicles (EVs) were first described; since then, the EV field has grown exponentially, revealing their vital roles in intracellular communication. In this review, we synthesize current knowledge on eosinophil-derived EVs, beginning with a description of what they are and what makes them important regulators of disease, followed by an account of the methodologies used to isolate and characterize EVs. We also summarize current understanding of eosinophil-derived vesicles functionality, especially in asthma, the disease in which eosinophil-derived EVs have been most widely studied, describing how they modulate the role of eosinophils themselves (through autocrine signaling) and the way they affect airway structural cells and airway remodeling. Deeper understanding of this cell type could lead to novel research in eosinophil biology, its role in other diseases, and possible use of eosinophil-derived EVs as therapeutic targets.

Managing Patients with Hypereosinophilic Syndrome: A Statement from the Italian Society of Allergy, Asthma, and Clinical Immunology (SIAAIC)

Hypereosinophilic syndrome (HES) encompasses a heterogeneous and complex group of different subtypes within the wider group of hypereosinophilic disorders. Despite increasing research interest, several unmet needs in terms of disease identification, pathobiology, phenotyping, and personalized treatment remain to be addressed. Also, the prospective burden of non-malignant HES and, more in general, HE disorders is currently unknown. On a practical note, shortening the diagnostic delay and the time to an appropriate treatment approach probably represents the most urgent issue, even in light of the great impact of HES on the quality of life of affected patients. The present document represents the first action that the Italian Society of Allergy, Asthma, and Clinical Immunology (SIAAIC) has finalized within a wider project aiming to establish a collaborative national network on HES (InHES-Italian Network on HES) for patients and physicians. The first step of the project could not but focus on defining a common language as well as sharing with all of the medical community an update on the most recent advances in the field. In fact, the existing literature has been carefully reviewed in order to critically integrate the different views on the topic and derive practical recommendations on disease identification and treatment approaches.

The role of radiological imaging in the management of severe and difficult-to-treat asthma

Radiological imaging has proven to be a useful tool in the assessment of asthma, its comorbidities and potential complications. Characteristic chest radiograph and computed tomography scan findings can be seen in asthma and in other conditions that can coexist with or be misdiagnosed as asthma, including chronic rhinosinusitis, inducible laryngeal obstruction, excessive dynamic airway collapse, tracheobronchomalacia, concomitant COPD, bronchiectasis, allergic bronchopulmonary aspergillosis, eosinophilic granulomatosis with polyangiitis, and eosinophilic pneumonia. The identification of the characteristic radiological findings of these conditions is often essential in making the correct diagnosis and provision of appropriate management and treatment. Furthermore, radiological imaging modalities can be used to monitor response to therapy.

Clinical and Therapeutic Intervention of Hypereosinophilia in the Era of Molecular Diagnosis

Hypereosinophilia (HE) presents with an elevated peripheral eosinophilic count of >1.5 × 109/L and is composed of a broad spectrum of secondary non-hematologic disorders and a minority of primary hematologic processes with heterogenous clinical presentations, ranging from mild symptoms to potentially lethal outcome secondary to end-organ damage. Following the introduction of advanced molecular diagnostics (genomic studies, RNA sequencing, and targeted gene mutation profile, etc.) in the last 1-2 decades, there have been deep insights into the etiology and molecular mechanisms involved in the development of HE. The classification of HE has been updated and refined following to the discovery of clinically novel markers and targets in the 2022 WHO classification and ICOG-EO 2021 Working Conference on Eosinophil Disorder and Syndromes. However, the diagnosis and management of HE is challenging given its heterogeneity and variable clinical outcome. It is critical to have a diagnostic algorithm for accurate subclassification of HE and hypereosinophilic syndrome (HES) (e.g., reactive, familial, idiopathic, myeloid/lymphoid neoplasm, organ restricted, or with unknown significance) and to follow established treatment guidelines for patients based on its clinical findings and risk stratification.

Concurrent Challenges in Idiopathic Hypereosinophilic Syndrome Complicating Beta-Thalassemia Major: A Case Report

This case report highlights the uncommon idiopathic hypereosinophilic syndrome (HES) complicating beta-thalassemia major, presenting a diagnostic and management challenge. Beta-thalassemia major, characterized by impaired beta-globin synthesis, necessitates regular blood transfusions and iron chelation therapy. HES, a rare disorder marked by persistent eosinophilia, adds complexity to the clinical course. We present the case of a 27-year-old male with beta-thalassemia major who developed fever, weakness, and weight loss and was subsequently diagnosed with HES. Treatment involved antibiotics, blood transfusions, and corticosteroids, leading to clinical improvement. This case underscores the need to further understand the relationship between thalassemia and eosinophilia and the importance of comprehensive evaluation in patients with overlapping hematological disorders.

Thrombotic Prediction Model Based on Epigenetic Regulator Mutations in Essential Thrombocythemia Patients Using Survival Analysis in Recurrent Events

INTRODUCTION

Essential thrombocythemia (ET) involves the proliferation of megakaryocytes and platelets and is associated with an increased risk of thrombosis. We aimed to evaluate thrombotic risks in patients with epigenetic regulator mutations and generate a model to predict thrombosis in ET.

MATERIALS AND METHODS

This cohort study enrolled patients aged > 15 years diagnosed with ET at the Songklanakarind Hospital between January 2002 and December 2019. Twenty-five targeted gene mutations, including somatic driver mutations (JAK2, CALR, MPL), epigenetic regulator mutations (TET2, DNMT3A, IDH1, IDH2, TET2, ASXL1, EZH2, SF3B1, SRSF2) and other genes relevant to myeloid neoplasms, were identified using next-generation sequencing. Thrombotic events were confirmed based on clinical condition and imaging findings, and thrombotic risks were analyzed using five survival models with the recurrent event method.

RESULTS

Ninety-six patients were enrolled with a median follow-up of 6.91 years. Of these, 15 patients experienced 17 arterial thrombotic events in total. Patients with JAK2 mutation and IDH1 mutation had the highest frequency of thrombotic events with somatic driver mutations (17.3%) and epigenetic regulator mutations (100%). The 10-year thrombosis-free survival rate was 81.3% (95% confidence interval: 72.0-91.8%). IDH1 mutation was a significant factor for thrombotic risk in the multivariate analysis for all models. The Prentice, William, and Peterson (PWP) gap-time model was the most appropriate prediction model.

CONCLUSIONS

The PWP gap-time model was a good predictive model for thrombotic risk in patients with ET. IDH1 mutation was significant risk factors for thrombosis; however, further studies with a larger sample size should confirm this and provide more insight.

An 85-Year-Old Man with Fever, Dyspnea, and Dry Cough Diagnosed with Idiopathic Hypereosinophilic Syndrome, Successfully Treated with High-Dose Corticosteroids

BACKGROUND Idiopathic hypereosinophilic syndrome (I-HES) is a rare disease diagnosed as absolute eosinophil count >1500 cells/µl and end-organ involvement attributable to tissue eosinophilia with no secondary cause of underlying eosinophilia. The mean age of presentation for I-HES is 44 years. The skin, lungs, and gastrointestinal (GI) system are most common sites of presenting manifestations, including fatigue, cough, dyspnea, myalgias, angioedema, rash, fever, nausea, and diarrhea. Although cardiac and neurologic symptoms are less common at presentation, they can be life-threatening. CASE REPORT We report the case of an 85-year-old man who presented with fever, malaise, and loss of appetite for 3 weeks, followed by dyspnea and dry cough for 2 weeks. His absolute eosinophil count was 9000 cells/µl, which was not responding to empirical antibiotic therapy, with worsening of symptoms, suggesting a non-infective origin. He was then extensively evaluated to establish underlying an etiology for specific treatment, which was negative for common causes like atypical infections, malignancy, and autoimmune disorders. He was then started on corticosteroid therapy to overcome an exaggerated immune response and reduce inflammation-related injury, to which he responded well. On follow-up, hypereosinophilia was fully cured, with reversal of end-organ involvement including myocarditis and pneumonitis. CONCLUSIONS This report shows that idiopathic HES can present with various clinical features and that accurate diagnosis, excluding known causes of eosinophilia, and early management are essential to prevent long-term organ damage. Our patient responded to prompt treatment with high-dose corticosteroids.

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

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

Clinico-radiological correlation and prognostic value of baseline chest computed tomography in eosinophilic granulomatosis with polyangiitis

OBJECTIVES

While chest high-resolution CT (HRCT) is correlated to severity and prognosis in asthma, it has not been studied in eosinophilic granulomatosis with polyangiitis (EGPA). Our objective is to study the prognostic value of baseline HRCT in EGPA patients.

METHODS

Retrospective, multicentre observational study in three French hospitals, including EGPA patients with available chest HRCT before any systemic treatment. Two experienced radiologists blinded to clinical data evaluated HRCT images using semi-quantitative scoring. HRCT characteristics were correlated with clinical features and outcome.

RESULTS

Among 46 patients, 38 (82.6%) had abnormal parenchymal findings on HRCT, including bronchial wall thickening (69.6%), mosaic perfusion (63.0%), ground-glass opacities (32.6%), bronchiectasis (30.4%), mucous plugging (21.7%) and consolidations (17.4%). Patients were clustered into three groups depending on HRCT features: ground-glass pattern, i.e. with ground-glass opacities with or without bronchial abnormalities (group 1, 28.3%), bronchial pattern (group 2, 41.3%) and extra-pulmonary pattern with no significant abnormality (group 3, 30.4%). Group 2 showed less frequent cardiac involvement (31.6 vs 46.2 and 42.9% in groups 1 and 3), more frequent positive ANCA (52.6 vs 0.0 and 14.3%) and higher eosinophil count (median 7510 vs 4000 and 4250/mm3). Group 1 showed worse prognosis with more frequent steroid-dependency (58.3 vs 11.1 and 28.6%) and requirement for mepolizumab (25.0 vs 11.1 and 7.1%). Conversely, group 2 showed a better outcome with higher rates of remission (88.9 vs 41.6 and 71.4%).

CONCLUSION

Chest HRCT at diagnosis of EGPA may have prognostic value and help clinicians better manage these patients.

Tuberculosis manifesting with significant peripheral eosinophilia: A case report and review of literature

Key Clinical Message

Peripheral eosinophilia is a rare but potential sign of TB infection. Physicians should assess patients for TB, especially if they display related symptoms or risk factors, and consider TB as a differential diagnosis, especially in idiopathic cases.

Abstract

Millions of new tuberculosis (TB) cases are reported annually. Peripheral eosinophilia is rare in tuberculosis. We describe a rare case of tuberculosis with a high peripheral eosinophil count. A 9-year-old male presented with fever, cough, and respiratory discomfort for a month. The patient's cough did not respond to treatment, along with weight loss and a loss of appetite. A physical examination revealed cervical lymphadenopathy and bilateral lung crepitations. A hematological investigation showed a high eosinophil count of 25,920 cells per cubic millimeter and medical imaging abnormalities consistent with TB. Some malignancies, allergies, and parasitic infections produce peripheral eosinophilia. However, medical literature rarely discusses TB-induced eosinophilia. Several studies attribute it to mycobacterium antigen hyperreactivity. Eosinophilic release of cytotoxic chemicals may cause tissue damage, and TB patients' eosinophil levels may fluctuate. This case report emphasizes the need to investigate TB in peripheral eosinophilia patients after ruling out other explanations. Our patient benefited from early detection and anti-TB medication. More studies are required to investigate the causes of TB eosinophilia and its consequences. A detailed medical history and physical examination are essential to diagnose and treat atypical presentations of TB.

Deterioration of lung function and its association with eosinophil count

Exposure to lethal dust particles has a negative impact on human's health. This work investigated the association between respiratory symptoms and eosinophil levels between quarry workers and the controls. A total of 75 workers exposed to quarry dust and 45 age, sex, body mass index-matched unexposed controls participated in this study. Results of this study indicated that the quarry dust particles produced inflammatory responses, increasing the mean eosinophil level (7.56 ± 2.94), causing allergic respiratory symptoms such as rhinitis , chest tightness, wheeze, sputum production thus impairing the lung function with decline in FEV1(80.84 ±108.8) level in workers exposed to quarry dust compared to controls (P≤0.00**) Conclusion: The presence of increased levels of respiratory irritants in quarry sites may explain the higher prevalence of respiratory infections and exacerbated inflammatory reactions found to ascertain the link between increased eosinophil count and the lung impairment in quarry workers.

Eosinophilic granulomatosis with polyangiitis - Advances in pathogenesis, diagnosis, and treatment

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare disease characterized by eosinophil-rich granulomatous inflammation and necrotizing vasculitis, pre-dominantly affecting small-to-medium-sized vessels. It is categorized as a primary antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs) but also shares features of hypereosinophilic syndrome (HES); therefore, both vessel inflammation and eosinophilic infiltration are suggested to cause organ damage. This dual nature of the disease causes variable clinical presentation. As a result, careful differentiation from mimicking conditions is needed, especially from HES, given the overlapping clinical, radiologic, and histologic features, and biomarker profile. EGPA also remains a diagnostic challenge, in part because of asthma, which may pre-dominate for years, and often requires chronic corticosteroids (CS), which can mask other disease features. The pathogenesis is still not fully understood, however, the interaction between eosinophils and lymphocytes B and T seems to play an important role. Furthermore, the role of ANCA is not clear, and only up to 40% of patients are ANCA-positive. Moreover, two ANCA-dependent clinically and genetically distinct subgroups have been identified. However, a gold standard test for establishing a diagnosis is not available. In practice, the disease is mainly diagnosed based on the clinical symptoms and results of non-invasive tests. The unmet needs include uniform diagnostic criteria and biomarkers to help distinguish EGPA from HESs. Despite its rarity, notable progress has been made in understanding the disease and in its management. A better understanding of the pathophysiology has provided new insights into the pathogenesis and therapeutic targets, which are reflected in novel biological agents. However, there remains an ongoing reliance on corticosteroid therapy. Therefore, there is a significant need for more effective and better-tolerated steroid-sparing treatment schemes.

Characteristics of patients with incidental eosinophilia admitted to a tertiary hospital in southern China

Background

The characteristics of patients with eosinophilia are heterogeneous and the outcomes can vary from asymptomatic to severe.

Objective

To describe the feature of patients with eosinophilia in a single center.

Design

Based on the electronic medical records from Yangjiang People's Hospital in China, the inpatients admitted between June 2018 and February 2021 with measured blood eosinophil counts were evaluated.

Methods

Eosinophilia was defined as a peripheral blood eosinophil count of ≥0.5 × 10⁹/L. Differences were compared by eosinophilia severity. The medical records of patients with moderate to severe eosinophilia were reviewed and summarized in terms of examination, diagnoses and management. And these patients were matched with patients without incidental eosinophilia by propensity score and the differences were compared.

Results

A total of 7,835 patients with eosinophilia were identified out of 131,566 total inpatients. All types of eosinophilia were most common in males (8.2%; 5,351/65,615), and in patients aged 0-6 years (11.6%; 1,760/15,204), and in the pediatric (10.8%; 1,764/16,336) department, followed by dermatology (10.6%; 123/1,162), Oncology (7.5%; 394/5,239) and Intensive care unit (ICU) (7.4%; 119/1,608). Patients with moderate to severe eosinophilia were more likely to admit to ICU (moderate: 1.3%; severe: 0.50%). In patients with moderate to severe eosinophilia, only 205/621 (33%) had eosinophilia mentioned in their records, and only 63/621 (10.1%) underwent investigations for eosinophilia. The majority of patients with moderate to severe eosinophilia (372/621, 59.9%) had an infectious disease, and little examination (7.4%; 46/621) was taken to identify the cause of eosinophilia, and only 39/621 (6.3%) of patients had a discrete cause of eosinophilia identified. Patients with moderate to severe eosinophilia (24.3%; 151/621) exhibited certain chance to have organ dysfunction.

Conclusion

Incidental eosinophilia in inpatients was frequently neglected and less investigated. Multidisciplinary consultation may improve outcomes of inpatients with moderate to severe eosinophilia.

Eosinophilia in children: characteristics, etiology and diagnostic algorithm

Eosinophilia is common in children and may be caused by various disorders. Large-cohort studies, including mild cases, are limited in children. This study aimed to reveal underlying etiologies of childhood eosinophilia and to create a diagnostic algorithm. Children (< 18 years) with absolute eosinophil counts (AECs) ≥ 0.5 × 10⁹/L were reviewed from medical files. Clinical characteristics and laboratory values were recorded. Patients were grouped based on the severity of eosinophilia as mild (0.5-1.5 × 10⁹/L), moderate (≥ 1.5 × 10⁹/L) and severe (≥ 5.0 × 10⁹/L). An algorithm was formed to evaluate these patients. We included 1178 children with mild (80.8%), moderate (17.8%) and severe eosinophilia (1.4%). The most common reasons of eosinophilia were allergic diseases (80%), primary immunodeficiency (PID) (8.5%), infectious diseases (5.8%), malignancies (0.8%) and rheumatic diseases (0.7%). Only 0.3% of children presented with idiopatic hypereosinophilic syndrome. Allergic diseases and PIDs were the most common etiologies in mild/moderate and severe groups, respectively. The median duration of eosinophilia was 7.0 (3.0-17.0) months in the study population and was the shortest in severe cases (2.0 (2.0-5.0) months). Multiple logistic regression analysis demonstrated food allergy [OR:1.866, 95%CI:1.225-2.842, p = 0.004] and PIDs [OR:2.200, 95%CI:1.213-3.992, p = 0.009] as independent factors for childhood eosinophilia. A diagnostic algorithm including mild form was presented for childhood eosinophilia.    Conclusion: Eosinophilia was frequently determined due to secondary causes; allergic diseases in mild/moderate eosinophilia, PIDs in severe group. Etiology of eosinophilia was diverse, and an algorithm concerning the severity of eosinophilia would be practical and rational. What is Known: • In children, eosinophilia is common, and mild eosinophilia occurs frequently. • Malignancies presents frequently with severe eosinophilia. What is New: • Primary immunodeficiencies were not a rare cause of eosinophilia, especially in countries such as the Middle East and eastern Mediterranean countries, where the countries consanguineous marriages are common, and should be investigated in children with eosinophilia who do not have allergic or infectious diseases. • In literature, there are many algorithms about childhood hypereosinophilia. However, mild eosinophilia is extremely important in children. Because all patients with malignancy and most of the patients with rheumatic diseases presented with mild eosinophilia. Therefore, we proposed an algorithm for childhood eosinophilia that includes mild eosinophilia besides moderate and severe cases.

Eosinophilic respiratory disorders and the impact of biologics

PURPOSE OF REVIEW

Eosinophils are involved in combating parasitic, bacterial, viral infections as well as certain malignancies. However, they are also implicated in an array of upper and lower respiratory disease states. Through a deeper understanding of disease pathogenesis, targeted biologic therapies have revolutionized glucocorticoid sparing treatment of eosinophilic respiratory diseases. This review will focus on the impact of novel biologics on the management of asthma, eosinophilic granulomatosis with polyangiitis, allergic bronchopulmonary aspergillosis (ABPA), hypereosinophilic syndrome (HES) and chronic rhinosinusitis with nasal polyposis (CRSwNP).

RECENT FINDINGS

Key immunologic pathways affecting Type 2 inflammation through immunoglobulin E (IgE), interleukin (IL-4), IL-5, IL-13, and upstream alarmins such as thymic stromal lymphopoietin (TSLP), have led to novel drug developments. We explore the mechanism of action for Omalizumab, Mepolizumab, Benralizumab, Reslizumab, Dupilumab, and Tezepelumab, their respective Food and Drug Administration (FDA) indications, and biomarkers affecting treatment decisions. We also highlight investigational therapeutics that are likely to impact the future management of eosinophilic respiratory diseases.

SUMMARY

Insight into the biology of eosinophilic respiratory diseases has been critical for understanding disease pathogenesis and has contributed to the development of effective eosinophil-targeted biologic interventions.

Hypereosinophilic syndrome in Europe: Retrospective study of treatment patterns, clinical manifestations, and healthcare resource utilization

BACKGROUND

The burden of hypereosinophilic syndrome (HES) in Europe is not well characterized.

OBJECTIVE

To evaluate real-world patient characteristics, treatment patterns, clinical manifestations, and healthcare resource utilization for patients with HES from France, Germany, Italy, Spain, and the United Kingdom.

METHODS

In this retrospective, noninterventional study, data for patients with a physician-confirmed diagnosis of HES were abstracted from medical chart reviews. Patients were aged 6 years or older at the time of HES diagnosis and had 1 or more years of follow-up from the index date (first clinic visit between January 2015 and December 2019). Data on treatment patterns, comorbidities, clinical manifestations, clinical outcomes, and healthcare resource utilization were collected from diagnosis or index date to end of follow-up.

RESULTS

Data for 280 patients were abstracted from medical charts by 121 physicians treating HES, with multiple specialties. Most patients (55%) had idiopathic HES, and 24% had myeloid HES; the median number (interquartile range [IQR]) of diagnostic tests per patient was 10 (6-12). The most common comorbidities were asthma (45%) and anxiety or depression (36%). Most patients (89%) used oral corticosteroids; 64% used immunosuppressants or cytotoxic agents, and 44% used biologics. Patients had a median (IQR) of 3 clinical manifestations (1-5), most commonly constitutional (63%), lung (49%), and skin (48%). Twenty-three percent of patients experienced a flare, and 40% had a complete treatment response. Some patients (30%) were hospitalized with a median (IQR) stay of 9 days (5-15) for HES-related issues.

CONCLUSION

Patients with HES across 5 European countries had a substantial disease burden despite extensive oral corticosteroids treatment, highlighting the need for additional targeted therapies.

Giant Coronary Artery Aneurysm with Thrombosis Complicated in a Patient with Idiopathic Hypereosinophilic Syndrome

Idiopathic hypereosinophilic syndrome (iHES) is a rare systemic disease that is characterized by persistent peripheral eosinophilia (absolute eosinophil count ≥1500/uL) for more than 6 months, with end-organ damage and absence of a primary cause for eosinophilia. Coronary artery aneurysm (CAA) is a rare but life-threatening complication. Here, we report a case of CAA with thrombosis in a patient with iHES in whom the disease activity was well-controlled (eosinophil count <500/uL) for several years. Despite modest control of the disease activity, giant CAA can be associated with iHES; and therefore, close surveillance and monitoring for the development of complications is warranted.

Case report: Successful use of mepolizumab for immune checkpoint inhibitors-induced hypereosinophilic syndrome in two patients with solid malignancies

Hypereosinophilic syndrome (HES) represents a group of blood disorders characterized by an absolute eosinophil count (AEC) > 1.5 × 103/μl in the peripheral blood, which eventually extravasate and cause organ damage. It can be primary or secondary to infections or tumors. The infiltration of eosinophils in tissue and organs is associated with different disorders and, in some cases, with life-threatening manifestations. Albeit the pathogenesis of HES in patients with solid tumo\rs is not yet clarified; recently, HES has also been described as an immune-related adverse event in patients with solid tumors receiving immune checkpoint inhibitors. Treatment of HES is still debated, especially in patients with concomitant solid tumors, and different drugs including imatinib, hydroxyurea, interferon-ɑ, glucocorticoids, and the monoclonal antibody targeting circulating IL-5 mepolizumab have been proposed according to the underlying cause and the severity of HES. Herein, we describe, for the first time, the successful use of mepolizumab for the treatment of immune checkpoint-induced HES in two patients with metastatic solid tumor.

Eosinophilia attention, diagnosis, treatment, and awareness in physicians: a cross-sectional survey

Background

Patients with incidental eosinophilia is becoming increasingly common in clinical practice. But it remains challenging to diagnose and treat owing to its complex etiology. The awareness of physicians and the strategies of diagnosis and treatment toward eosinophilia are still unclear.

Objective

We aimed to evaluate attention, diagnosis, treatment, and awareness of eosinophilia among physicians, as well as factors influencing clinical practice, and to find ways to improve the efficacy of this disease.

Design

This is a cross-sectional survey.

Methods

A cross-sectional study was conducted from 1 to 4 June 2021 in a tertiary hospital. Self-administered and validated electronic questionnaire was used to investigate the attention toward eosinophilia, the strategies of diagnosis and treatment, and the awareness in physicians.

Results

A total of 607 valid questionnaires were collected, with a response rate of 84.5%. Among the responders, 65.4% of physicians claimed to be familiar with patients with eosinophilia but only 11.0% of them had read the relevant guidelines or expert consensus. Among 207 physicians who had ever diagnosed patients with eosinophilia, only 19.4% had performed detailed examinations. The accuracy of awareness questions was 1.6-53.5%, and only 26.5% of physicians had high levels of awareness. An increase in the awareness level of up to 2.82 folds was seen among physicians with factors such as job title, encountering patients with eosinophilia, linking patients' conditions to peripheral blood eosinophil count, and paying attention to guidelines.

Conclusion

This study highlighted the importance of raising awareness and knowledge of eosinophilia among physicians in China. More works on education about eosinophilia guideline are needed, which may help physicians make decision with more benefits to patients.

Perioperative Respiratory Outcome of Patients with Eosinophilia: A Cohort Study in a Tertiary Care Hospital

Background

A respiratory adverse event is one of the main causes of critical events in the perioperative period. Perioperative distress symptoms like cough and stridor have been reported to occur in patients with hyperreactive airways.

Objective

This study was conducted to determine the relationship between blood eosinophil count and perioperative adverse respiratory events among different age groups of patients who require general anesthesia for different types of surgeries.

Methods

A cohort study was conducted on 197 patients of either gender, aged 3 years and above, belonging to ASA classes I-II, who were scheduled to undergo surgery requiring general anesthesia and intubation. Patients were stratified according to absolute eosinophil count into two groups: Group A (AEC 0 to 499/mm³) and Group B (AEC 500 to 1000/mm³). Patients were monitored for 24 hours in the perioperative period for adverse respiratory events such as bronchospasm, laryngospasm, a fall in SPO2 < 95%, and cough and stridor.

Results

A total of 197 patients were evaluated, with a median age of 37 ± 14.4 years. The percentage range of adverse respiratory events across different age groups was 35% in adults to 60% in children. Major complications noted were a fall in SPO2 < 95% (62.5%) and cough (27.7%) as per CTCAE v5.0 (November 27, 2017). The Naranjo score of adverse respiratory events was categorized as possible with mild level 1 severity. Adverse respiratory events were managed with humidified oxygen, antitussives, and bronchodilators.

Conclusions

Eosinophilia is seen in one-third of the patients undergoing surgical interventions. Patients with a blood eosinophil count of ≥400/mm³ had an increased risk of exacerbations of respiratory adverse events in the perioperative period.

Strongyloides stercoralis: Uncommon yet not to be missed cause of eosinophilia

Strongyloides stercoralis is a soil-transmitted nematode that is estimated to infect millions of people per year worldwide. However, cases are less commonly seen in the United States. This report highlights the importance of when to include Strongyloides stercoralis in the differential diagnosis of patients presenting eosinophilia within the United States.

Idiopathic Hypereosinophilia: A Multicenter Retrospective Analysis

PURPOSE

Physicians can sometimes encounter idiopathic hypereosinophilia (HE), but little is known about it. In this multicenter study, we analyzed the clinical characteristics, treatment, and outcomes of patients with idiopathic HE.

PATIENTS AND METHODS

Patients diagnosed with idiopathic HE (idiopathic hypereosinophilic syndrome: iHES or hypereosinophilia with undetermined significance: HEus) at six tertiary hospitals between January 2010 and June 2021 were included in this retrospective observational study. Demographics, clinical and laboratory data, and treatment responses were obtained from the electronic medical records of the study subjects.

RESULTS

A total of 73 patients with idiopathic HE (45 with iHES and 28 with HEus) were included in the present study. Overall, 12 (26.7%) and 5 (17.9%) were women, and mean age of patients at diagnosis was 51.84 ± 17.29 years and 60.21 ± 18.01 years in iHES and HEus groups, respectively. Forty-three (95.6%) patients of iHES and 15 (53.6%) patients of HEus received corticosteroids as 1st-line treatment. Treatment response to corticosteroids in patients with iHES was generally good: complete response (n=25, 58.1%), partial response (n=12, 27.9%), no response (n=6, 14.0%). Treatment response to corticosteroids in HEus was complete response (n=7, 46.7%), partial response (n=6, 40.0%), and no response (n=2, 13.3%). There were 13 patients (46.4%) with HEus who were not treated.

CONCLUSION

Corticosteroid treatment is generally effective and well tolerated by patients with iHES. Some patients with HEus are treated with corticosteroids in clinical practice. Extensive research is needed to establish a standardized management guidelines for iHES and determine whether treatment for HEus is required.

Mepolizumab Reduces Hypereosinophilic Syndrome Flares Irrespective of Blood Eosinophil Count and Interleukin-5

BACKGROUND

Mepolizumab, an anti-interleukin-5 (IL-5) antibody, reduces disease flares in patients with hypereosinophilic syndrome (HES). Factors predicting treatment response are unknown.

OBJECTIVE

To assess mepolizumab efficacy by baseline blood eosinophil count (BEC) and serum IL-5 level in patients with HES.

METHODS

This post hoc analysis used data from the phase III study assessing mepolizumab in patients with HES (NCT02836496). Patients 12 years old or older, with HES for 6 or more months, 2 or more flares in the previous year, and BEC ≥1,000 cells/μL at screening were randomized (1:1) to 4-weekly subcutaneous mepolizumab (300 mg) or placebo, plus baseline HES therapy, for 32 weeks. The proportion of patients experiencing 1 or more flares (wk 32), annualized flare rate, and proportion of patients with change from baseline in Brief Fatigue Inventory (BFI) item 3 (wk 32), were analyzed by baseline BEC (<1500/≥1500 to <2500/≥2500 cells/μL). Flare outcomes were assessed by baseline serum IL-5 (<7.81/≥7.81 pg/mL).

RESULTS

Across baseline BEC subgroups, mepolizumab reduced the proportion of patients experiencing 1 or more flares by 63% to 90% and flare rate by 58% to 84% (treatment-by-eosinophil interaction P = .76 and P = .90, respectively); patients had improved BFI item 3 score with mepolizumab versus placebo (cells/μL: <1,500: 54% vs 37%; ≥1,500 to <2,500: 47% vs 31%; ≥2,500: 61% vs 0%; treatment-by-eosinophil interaction P = .42). Most patients had undetectable baseline serum IL-5 levels; among these, mepolizumab versus placebo reduced the proportion of patients with 1 or more flares (77%) and flare rate (67%).

CONCLUSIONS

Mepolizumab was efficacious in the patients with HES studied, irrespective of baseline BEC. Undetectable IL-5 levels should not preclude mepolizumab treatment.

A diagnostic score for eosinophilic granulomatosis with polyangiitis among eosinophilic disorders

BACKGROUND

Eosinophilic granulomatosis with polyangiitis (EGPA) is a form of systemic vasculitis with eosinophilic inflammation. However, existing classification criteria are all designed to classify EGPA among vasculitis and there is no established method distinguishing EGPA from other eosinophilic disorders. The aim of the present study was to propose a scoring system to differentiate EGPA among eosinophilic disorders.

METHODS

Non-supervised hierarchical clustering using Ward's method and principal component analysis (PCA) were performed for 19 clinical parameters of 58 patients with eosinophilia-related diseases at a tertiary university hospital. The newly proposed scoring system was externally validated in 40 patients at another tertiary institution.

RESULTS

Two distinct clusters were identified, and clinical features including peripheral neuropathy, asthma, skin involvement, lung involvement, rheumatoid factor (RF) positivity, myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA) positivity, IgE elevation, C-reactive protein (CRP) elevation, and vasculitis pathological findings were predominantly observed in one of these clusters (p < 0.05). Ten features defining the cluster with a high rate of vasculitis were weighted by PCA to create the E-CASE (EGPA classification among systemic eosinophilia) scoring system, on a 16-point scale. Based on the distribution of scores in the primary cohort, we defined an E-CASE score ≥12 as positive, ≤ 8 as negative, and 9-11 as undeterminable. The sensitivity and specificity of the E-CASE score in the validation cohort were 93.3% and 100%, respectively.

CONCLUSIONS

We developed and verified a novel scoring system for differentiating EGPA from other types of eosinophilic disorders.

Acute exacerbation of idiopathic hypereosinophilic syndrome following asymptomatic coronavirus disease 2019: a case report

BACKGROUND

Previous research has suggested that some autoimmune diseases develop after the occurrence of coronavirus disease 2019. Hypereosinophilic syndrome is a rare disease presenting with idiopathic eosinophilia and multiple organ involvement, including the skin, lungs, gastrointestinal tract, heart, and nervous system. The diagnosis of idiopathic hypereosinophilic syndrome poses a dilemma because clinical manifestation and serum biomarkers are similar to those of eosinophilic granulomatosis with polyangiitis. Only a few cases have been reported where coronavirus disease 2019 may have caused the new onset or exacerbation of eosinophilic granulomatosis with polyangiitis or idiopathic hypereosinophilic syndrome.

CASE PRESENTATION

We present the case of a 48-year-old Japanese woman with history of asthma who developed deteriorating symptoms of insidiously developed idiopathic hypereosinophilic syndrome following asymptomatic coronavirus disease 2019. She developed acute-onset back pain, tachycardia, abdominal discomfort, loss of appetite, weight loss, skin rash on the back, and numbness of the extremities 3 days after the quarantine period. Extreme hypereosinophilia with multiple abnormal findings including pulmonary ground-glass opacity lesions and mononeuritis multiplex was consistent with hypereosinophilic syndrome. Normal cellularity with eosinophilic proliferation in the bone marrow and negative FIP1L1-PDGFRA raised the diagnosis of idiopathic hypereosinophilic syndrome. Although the patient tested negative for anti-neutrophilic cytoplasmic antibodies and skin biopsy was negative for vasculitis, eosinophilic granulomatosis with polyangiitis could not be excluded. Since glucocorticoids are a standard therapy for both idiopathic hypereosinophilic syndrome and eosinophilic granulomatosis with polyangiitis, we initiated glucocorticoids following a multidisciplinary discussion.

CONCLUSION

Although the relationship between asymptomatic coronavirus disease 2019 and acute idiopathic hypereosinophilic syndrome exacerbation was uncertain, the chronological order of the symptomatic development suggested a possible link. More clinical cases and population-based studies are needed to determine the potential effect of coronavirus disease 2019 on autoimmune diseases.

Characterization of disease flares and impact of mepolizumab in patients with hypereosinophilic syndrome

In patients with hypereosinophilic syndrome (HES), mepolizumab reduces the incidence of HES-related clinical signs and symptoms (flares). However, reports characterizing flare manifestations are limited. The double-blind, parallel-group 200622 trial (NCT02836496) enrolled patients ≥12 years old with HES for ≥6 months, ≥2 flares in the previous year, and screening blood eosinophil count ≥1000 cells/μL. Patients maintained ≥4 weeks stable HES therapy, before randomization (1:1) to 4-weekly subcutaneous mepolizumab (300 mg) or placebo, plus baseline HES therapy, for 32 weeks. This post hoc analysis investigated flare manifestations and duration by re-examining the Core Assessments form and narrative recorded for each flare during the study. Flare symptoms were retrospectively categorized into constitutional, dermatological, respiratory, nasal, gastrointestinal, neurologic and other. The most frequently reported flare symptoms were constitutional (94% of flares), dermatological (82% of flares) and respiratory (72% of flares); flares reported in patients receiving mepolizumab compared with placebo were generally similar in terms of the frequency of symptoms reported. Mepolizumab was associated with a shorter median (range) duration of flares (10.0 [4, 126] days) versus placebo (26.0 [1, 154] days). In patients with HES, flares were associated with symptoms linked to multiple organ systems highlighting the challenges faced for treating flares.

Clinical Trial Registration

https://clinicaltrials.gov/ct2/show/NCT02836496, identifier NCT02836496.

Clinical Profile and Treatment in Hypereosinophilic Syndrome Variants: A Pragmatic Review

BACKGROUND

Hypereosinophilic syndrome (HES) is a group of rare hematologic disorders leading to eosinophil-driven tissue damage and dysfunction. Better understanding of HES variants may facilitate improved patient management.

OBJECTIVE

To describe disease characteristics, treatment, and outcomes of patients with idiopathic (I-HES), myeloproliferative (M-HES), lymphocytic (L-HES), and chronic eosinophilic leukemia, not otherwise specified (CEL-NOS) among HES case reports and aggregate data where available.

METHODS

Relevant articles published between January 1, 2000, and March 20, 2020, were retrieved via PubMed; those reporting secondary, associated/reactive, overlap/single-organ, or familial HES were excluded.

RESULTS

Of 188 articles included, 171 contained data on 347 separate HES cases (152 I-HES, 121 M-HES, 62 L-HES, 12 CEL-NOS). Based on individual data, mean age at diagnosis was 43 to 48 years for patients with all HES variants. Males accounted for 90% to 91% of M-HES/CEL-NOS and 55% to 65% of I-HES/L-HES cases. Cardiac symptoms were frequently observed for all HES variants (13%-22% of patients). Respiratory symptoms (I-HES), splenomegaly (M-HES and CEL-NOS), and skin conditions (L-HES) were also frequently observed. Bone marrow, heart, lung, spleen, liver, skin, and lymph nodes were commonly involved. Most patients with I-HES, L-HES, and CEL-NOS received corticosteroids (65%-85%), whereas most with M-HES received imatinib (81%); those with CEL-NOS also received interferon alpha (42%).

CONCLUSIONS

Collective analysis of HES case reports supports and extends current understanding of HES variants, highlighting differences in signs and symptoms, organ involvement, and treatment approaches. Improved characterization of HES variants may facilitate the development of novel treatments.

Follow-Up of a Rare Case of Eosinophilic Gastroenteritis Associated with Persistent Blood Eosinophilia and Multiple Food Allergies

Eosinophilic gastroenteritis (EGE) is a subgroup of the eosinophilic gastro-intestinal disorders (EGIDs), characterized by eosinophilic infiltration and chronic inflammation of the gastrointestinal tract. These are rare diseases with still incompletely elucidated causes and mechanisms, with frequently delayed diagnosis and variable outcome. Despite increased interest in eosinophilic diseases in recent years, fewer data have been published on EGE and no standardized diagnostic and therapeutic approach exists. This paper reports the case of a young male patient diagnosed with EGE in 2017 based on clinical and histopathological criteria and constantly monitored during five years. Besides gastrointestinal eosinophilic infiltration, biopsies also revealed eosinophilic infiltration of the oesophagus, despite no declared characteristic oesophageal symptoms. We found increased specific IgE to multiple foods and progressive blood hypereosinophilia which preceded EGE diagnosis by three years. The EGE management included selective dietary restrictions and pharmacologic therapy based on daily budesonide non-enteric coated tablets, proton pumps inhibitors, antihistamines, cromoglycate, correction of iron, calcium and vitamin D deficiencies. The clinical outcome was good, while blood eosinophilia and endoscopic appearance remained almost unchanged. After one year the patient complained of respiratory symptoms suggesting asthma, needing continuous combined inhaled therapy. The reported case is illustrative for complex presentation, diagnosis and outcome of a rare case of mucosal chronic EGE associated with oesophageal involvement, peripheral eosinophilia, multiple food allergies and asthma.

Hypereosinophilia management in patients with type 2 chronic rhinosinusitis treated with dupilumab: preliminary results

PURPOSE

Biological therapies are gaining relevance in the management of CRSwNP with few adverse events reported. Among these, dupilumab, an anti-IL4-Ra monoclonal antibody, is frequently associated with hypereosinophilia (HE) which usually remains silent and progressively resolves, although some cases of systemic involvement occurs. The aim of this paper is to describe our experience and propose a management flowchart for HE during therapy with dupilumab.

METHODS

Patients with CRSwNP who satisfied EPOS2020 criteria for biological therapies were included in this prospective study. Each case was discussed in a multidisciplinary meeting with subsequent prescription of dupilumab; all patients were candidates to follow-up bi-monthly for 6 months, while additional blood tests were scheduled in the event of HE.

RESULTS

A total of 21 patients with a mean age of 48.4 years were enrolled. Of these, 15 of 21 presented an asthma comorbidity and 9 of 21 ASA sensitivity. Four patients (19%) developed HE with AEC > 1.5 × 10⁹/L, whereas it occurred in 9.5% (two patients) if considered AEC > 3 × 10⁹/L. No cases of hypereosinophilic syndrome were recorded. Following our decision-making flowchart, two patients received short-term corticosteroid therapy, whereas the other two were only eligible for closer follow-up.

CONCLUSIONS

During dupilumab therapy, HE may occur and should be considered benign when < 3 × 10⁹/L in the absence of organ involvement. Conversely, in case of HE ≥ 3 × 10⁹/L, an empirical approach with short-term corticosteroid therapy should be considered to debulk the blood from eosinophils and prevent potential organ involvement.

Association Between Baseline Therapy and Flare Reduction in Mepolizumab-Treated Patients With Hypereosinophilic Syndrome

Background

Current standard-of-care treatments for hypereosinophilic syndrome (HES) include oral corticosteroids (OCS) and immunosuppressive/cytotoxic (IS/CT) therapies. The anti-IL-5 monoclonal antibody mepolizumab has also recently been approved for patients with this disease. The objective of this analysis was to assess the relationship between baseline therapy and flare reduction in patients with HES treated with mepolizumab, using data from the Phase III 200622 study (NCT02836496).

Methods

In the double-blind, parallel-group 200622 study, eligible patients were ≥12 years old and had HES for ≥6 months, ≥2 flares in the previous 12 months, blood eosinophils ≥1000 cells/μL at screening and ≥4 weeks’ stable HES therapy. Patients were randomised (1:1) to receive mepolizumab 300 mg subcutaneously or placebo every 4 weeks for 32 weeks plus their existing HES therapy. This post hoc, descriptive analysis assessed the effect of baseline HES therapy [IS/CT (± OCS), OCS No IS/CT, and No IS/CT/OCS] on the proportion of patients with ≥1 flare during the study period, the annualised rate of flares, time to first flare, and the proportion of patients with ≥1 flare during Weeks 20─32, with mepolizumab versus placebo.

Results

Mepolizumab treatment was associated with a decrease in the proportion of patients who experienced ≥1 flare during the study period in all baseline therapy groups versus placebo (32–96% reduction). Similarly, the probability of a flare was lower with mepolizumab (14.3–31.4%) than placebo (35.7–74.1%) in all baseline therapy groups, as was the annualised flare rate (0.22–0.68 vs 1.14–1.62). The proportion of patients who experienced ≥1 flare during Weeks 20–32 was reduced with mepolizumab versus placebo for all baseline therapy groups (55–85% reduction). For all endpoints, the greatest effect of mepolizumab treatment was seen in the IS/CT (± OCS) group.

Conclusions

Patients with poorly controlled HES are likely to achieve clinical benefit with mepolizumab in terms of flare reduction, regardless of their baseline therapy.

Clinical Trial Registration

(https://clinicaltrials.gov/ct2/show/NCT02836496).

A Rare Case of Eosinophilic Ileitis and the Role of Motorized Spiral Enteroscopy in Its Diagnosis

<b><i>Introduction:</i></b> Eosinophilic gastrointestinal disorders are rare idiopathic conditions characterized by eosinophilic infiltration of any area of the gastrointestinal tract. The clinical presentation is variable and depends on the location and depth of the eosinophilia. Peripheral eosinophilia or elevated serum IgE levels may be present and histological analysis is necessary to a definite diagnosis. <b><i>Presentation:</i></b> A 40-year-old male presented with generalized abdominal pain, nausea, vomiting, diarrhea and anorexia for 1 month and unintended weight loss for 2 months. He had anemia, peripheral eosinophilia, slight hypokalemia, an elevated fecal calprotectin and “a thin sheet of bilateral pleural effusion, reduced-volume ascites and parietal thickening of the entire ileum” in the thoracoabdominal CT scan. An elevated serum IgE was absent and stool for parasites or bacteria, viral serologies, mycobacteria direct exam and culture, and celiac disease screening were negative. The endoscopic exams showed no significant alterations; random ileal biopsies were collected by antegrade motorized spiral enteroscopy and revealed a very fragmented mucosa with inflammatory infiltrate with about 35 eosinophils per high-power field and an altered eosinophil distribution in the ileal wall. The patient initiated oral prednisolone for eosinophilic ileitis, with clinical, analytical, and imagiological improvement. <b><i>Conclusion:</i></b> Eosinophilic ileitis is a rare condition but should be considered in the differential diagnosis of unexplained gastrointestinal symptoms and ascites, particularly in the presence of peripheral eosinophilia. Motorized spiral enteroscopy can be helpful in the diagnosis, allowing the collection of biopsy specimens effectively and safely.

Safety and efficacy of mepolizumab in hypereosinophilic syndrome: an open-label extension study

BACKGROUND

A double-blind, placebo-controlled Phase III study (200622) showed that mepolizumab reduces disease flares for patients with uncontrolled FIP1L1-PDGFRA-negative hypereosinophilic syndrome (HES) and ≥2 flares in the previous year.

OBJECTIVES

To further characterize the safety, clinical benefit, and pharmacodynamics of mepolizumab.

METHODS

Eligible patients from both treatment arms of the double-blind study could enter an open-label extension (OLE) study (205203; NCT03306043) to receive 4-weekly mepolizumab (300 mg subcutaneously) plus background therapy for 20 weeks. Primary endpoints were safety-based; other endpoints included flare rates and changes from baseline in mean daily oral corticosteroid (OCS) dose and blood eosinophil count (BEC).

RESULTS

Of 104 patients who completed the double-blind study, 98% (previous placebo n=52; previous mepolizumab n=50) enrolled in the OLE. Overall, 66 (65%) patients reported adverse events (AEs); 15 (15%) reported treatment-related AEs and 9 (9%) reported serious AEs. No events were fatal. The annualized flare rate (95% confidence interval) in the previous placebo and previous mepolizumab groups was 0.37 (0.16, 0.86) and 0.14 (0.04, 0.49) events/year, respectively. Of 72 patients receiving OCS during Weeks 0-4, 20 (28%; previous placebo, n=14; previous mepolizumab, n=6) achieved ≥50% reductions in mean daily dose during Weeks 16-20. At Week 20, BEC was reduced by 89% in patients previously receiving placebo and remained reduced for those previously receiving mepolizumab.

CONCLUSION

Extended mepolizumab treatment was associated with a positive benefit:risk profile. Continued control of disease flares and blood eosinophil counts, plus reductions in OCS use, were observed with mepolizumab in patients with FIP1L1-PDGFRA-negative HES.

Episodic angioedema with eosinophilia (Gleich's syndrome) associated with urticarial vasculitis: a coincidence or a novel clinical entity?

Episodic angioedema with eosinophilia (EAE) is a rare condition characterized by recurrent attacks of angioedema and urticaria accompanied by a marked elevation of peripheral eosinophil count. We report the case of a young female patient diagnosed with EAE associated with urticarial vasculitis. A 40-year-old female patient was admitted to our institution due to recurrent episodes of cheek and eyelid angioedema in the previous year. Episodes of facial angioedema lasted for two months with spontaneous remission afterwards. In addition, she presented pruritic and painful skin eruptions of erythematous circles, which persisted for longer than 24 h, that were palpable, somewhat purplish, and more pronounced on the face, arms, and trunk. Laboratory investigation showed a sustained elevation of white cell counts with marked eosinophilia. Serum IgM, IgE, and IgA were normal; IgG was slightly elevated. C1-esterase inhibitor and tryptase test were normal. Reverse transcriptase-polymerase chain reaction was performed for detection of FIP1L1-PDGFRA and BCR-ABL rearrangements. None of these alterations were found. Skin biopsies were suggestive of urticarial vasculitis. The patient was submitted to esophagogastroduodenoscopy, which showed mild chronic gastritis, with no eosinophilic infiltration. Cardiac dimensions and function were normal. Abdominal ultrasound and total body CT-scan failed to show lymphadenopathy, organomegaly, and tumors. We report the first case of association between episodic angioedema with eosinophilia and urticarial vasculitis. It is possible that both conditions share a physiopathological mechanism, suggesting that it is not just a chance association.

Molecular Pathogenesis and Treatment Perspectives for Hypereosinophilia and Hypereosinophilic Syndromes

Hypereosinophilia (HE) is a heterogeneous condition with a persistent elevated eosinophil count of >350/mm³, which is reported in various (inflammatory, allergic, infectious, or neoplastic) diseases with distinct pathophysiological pathways. HE may be associated with tissue or organ damage and, in this case, the disorder is classified as hypereosinophilic syndrome (HES). Different studies have allowed for the discovery of two major pathogenetic variants known as myeloid or lymphocytic HES. With the advent of molecular genetic analyses, such as T-cell receptor gene rearrangement assays and Next Generation Sequencing, it is possible to better characterize these syndromes and establish which patients will benefit from pharmacological targeted therapy. In this review, we highlight the molecular alterations that are involved in the pathogenesis of eosinophil disorders and revise possible therapeutic approaches, either implemented in clinical practice or currently under investigation in clinical trials.

Dendritic cell-CD4+ T cell interaction: The differential role of IL-4/IL-13 in serum IgE levels in house dust mite allergic patients

Allergic asthma is a chronic airway inflammatory disorder triggered by inhalant allergens. Interleukin (IL)-4 and IL-13 play a main role in the generation of T helper cell type 2 (Th2) immune response, induction of immunoglobulin E (IgE) synthesis and persistence of airway inflammation. The aim of the present study was to investigate the influence of Dermatophagoides pteronyssinus allergen Der p 1, the major allergen of house dust mite, on the synthesis of IL-4 and IL-13 by monocyte-derived dendritic cells (DCs) and naive CD4+ T cells cocultured with DCs, as well as their role in the production of serum IgE, in house dust mite (HDM) allergic patients. Peripheral blood mononuclear cells (PBMCs) were isolated from venous blood of patients allergic to HDM and healthy donors and incubated with granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-4 to generate immature DCs. The obtained cells were stimulated for 24 h with Der p 1 to induce DC maturation, washed, and afterwards cocultured for 24 h with autologous naive CD4+ T cells. Culture supernatants were harvested for IL-4, IL-13 and IFN-γ level measurements. DCs stimulation with Der p 1 induced higher synthesis of IL-4 and IL-13 in HDM allergic patients, compared to healthy donors. The allergic group showed significant correlation between IL-13 production by Der p 1-pulsed DCs, and total serum IgE and IL-4 production of the same cells and Der p-specific IgE. To conclude, IL-4 and IL-13 are critically related to the regulation of serum IgE production in patients with allergic asthma. The relevance of these two cytokines in the pathophysiology of Th2 asthma endotype makes them an appropriate target in its management.

Highlights and recent developments in allergic diseases in EAACI journals (2019)

The European Academy of Allergy and Clinical Immunology (EAACI) owns three journals: Allergy, Pediatric Allergy and Immunology and Clinical and Translational Allergy. One of the major goals of EAACI is to support health promotion in which prevention of allergy and asthma plays a critical role and to disseminate the knowledge of allergy to all stakeholders including the EAACI junior members. There was substantial progress in 2019 in the identification of basic mechanisms of allergic and respiratory disease and the translation of these mechanisms into clinics. Better understanding of molecular and cellular mechanisms, efforts for the development of biomarkers for disease prediction, novel prevention and intervention studies, elucidation of mechanisms of multimorbidities, entrance of new drugs in the clinics as well as recently completed phase three clinical studies and publication of a large number of allergen immunotherapy studies and meta-analyses have been the highlights of the last year.

COVID-19: Are we dealing with a multisystem vasculopathy in disguise of a viral infection?

After the emergence of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) and Middle East Respiratory Syndrome Coronavirus (MERS-CoV) in the last two decades, the world is facing its new challenge in Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic with unprecedented global response. With the expanding domain of presentations in COVID-19 patients, the full range of manifestations is yet to unfold. The classical clinical symptoms for SARS-CoV-2 affected patients are dry cough, high fever, dyspnoea, lethal pneumonia whereas many patients have also been found to be associated with a few additional signs and clinical manifestations of isolated vasculopathy. Albeit a deep and profound knowledge has been gained on the clinical features and management of COVID-19, less clear association has been provided on SARS-CoV-2 mediated direct or indirect vasculopathy and its possible correlation with disease prognosis. The accumulative evidences suggest that novel coronavirus, apart from its primary respiratory confinement, may also invade vascular endothelial cells of several systems including cerebral, cardio-pulmonary as well as renal microvasculature, modulating multiple visceral perfusion indices. Here we analyse the phylogenetic perspective of SARS-CoV-2 along with other strains of β-coronaviridae from a standpoint of vasculopathic derangements. Based on the existing case reports, literature and open data bases, we also analyse the differential pattern of vasculopathy related changes in COVID-19 positive patients. Besides, we debate the need of modulation in clinical approach from a hemodynamical point of view, as a measure towards reducing disease transmission, morbidity and mortality in SARS-CoV-2 affected patients.

Central Nervous System and Cardiac Involvement in the Hypereosinophilic Syndrome: A Case Report

Hypereosinophilic syndrome is a rare entity and heterogeneous group of disorders characterized by hypereosinophilia and organ involvement. In this study, we presented a 49-year-old woman with cardiac tamponade in the context of Hypereosinophilic syndrome. Identifying hypereosinophilia as the underlying cause can have tremendous clinical implications for rapid initiation of appropriate treatment to minimize further end organ damage.

Mast cell activation syndromes - evaluation of current diagnostic criteria and laboratory tools in clinical practice (Review)

Mast cell activation syndromes (MCAS) represent a heterogeneous clinical entity caused by episodic and severe mast cell activation, including primary and secondary mast cell disorders (MCDs). The group of primary or clonal MCDs refers to systemic mastocytosis, other clonal MCAS and hereditary hypertryptasemia, while the secondary MCAS is characterized by normal mast cells (MCs) which are activated by external triggers, such as allergens or physical stimuli. Another category of MCAS is the idiopathic form, when no trigger or genetic mutation can be identified. Symptoms of mast cell activation are due to release of specific mediators and can be seen in many diseases, such as allergies, with localized or systemic clinical manifestations. Confirmation of MCAS is based on diagnostic criteria proposed by an international group of experts and the best available evidence in this field. It is generally accepted that the clinical picture of MCAS is non-specific and there are few available laboratory tools, making it difficult for clinicians to identify and confirm this entity. The diagnosis is established after exclusion of other possible clinical entities in most of the cases. Therefore, the actual diagnostic criteria of MCASs, some relevant clinical aspects and laboratory tools used in clinical practice were reviewed.

Hypereosinophilic Syndrome, Multiorgan Involvement and Response to Imatinib

Hypereosinophilic syndrome (HES) is an uncommon syndrome characterized by peripheral blood eosinophils count of more than 1,500/mm³ with associated tissue damage. It can be either primary or secondary, for example, due to parasitic infections or inflammation.

We present a case of a 49-year-old Asian female with recurrent hospital admissions for cholecystitis, gastritis, urinary cystitis, and pancreatitis. Her peripheral blood count showed excessive eosinophils 15,600-19,000/mm³ on different occasions. Pathology of her gallbladder and her gastric biopsies showed eosinophilic infiltration. Her bone marrow biopsy showed a normocellular marrow with active trilineage hematopoiesis, eosinophilia, mild megakaryocytic hyperplasia with a few atypical forms, and mild T-cell lymphocytosis. Flow cytometry showed no evidence of acute leukemia, or T-cell or B-cell lymphoproliferative disorder. On fluorescent in-situ hybridization (FISH), myeloproliferative neoplasms (MPN) testing was negative for platelet-derived growth factor receptor-alpha (PDGFRA), platelet-derived growth factor receptor-beta (PDGFRB), and fibroblast growth factor receptor-1 (FGFR1) rearrangement. Despite not having the FIP1L1‐PDGFRA (factor interacting with PAPOLA and CPSF1-platelet-derived growth factor receptor, alpha polypeptide) gene fusion, our patient responded to the treatment with a significant decrease in her absolute eosinophils count and resolution of her symptoms.

Blood Eosinophils Subtypes and Their Survivability in Asthma Patients

Eosinophils subtypes as lung-resident (rEOS) and inflammatory (iEOS) eosinophils are different in surface protein expression, functions, response to IL-5 and localization in lungs. rEOS- and iEOS-like eosinophils are found in blood; thus, we aimed to investigate their quantity and survivability in asthma patients. A total of 40 individuals were included: 10 steroid-free non-severe allergic asthma (AA), and 18 severe non-allergic eosinophilic asthma (SNEA) patients, the control group consisted of 12 healthy non-smoking subjects (HS). A bronchial challenge with Dermatophagoides pteronysinnus allergen was performed for AA patients and HS. Blood eosinophils subtyping was completed with magnetic beads' conjugated antibodies against surface CD62L. Eosinophils adhesion to hTERT airway smooth muscle (ASM) cells was measured by evaluating their peroxidase activity and viability by annexin V and propidium iodide staining. We found that the predominant blood eosinophil subtype in AA patients was iEOS, while rEOS prevailed in SNEA patients (p < 0.05). Moreover, rEOS demonstrated higher adhesion intensity compared with iEOS in all investigated groups. Both eosinophils subtypes of SNEA patients had higher survivability over the AA group. However, iEOS survivability from AA and SNEA groups was higher compared with rEOS under standard conditions, when rEOS survivability increased after their incubation with ASM cells. Bronchial allergen challenge abolished the dominance of blood iEOS in AA patients and prolonged only iEOS survivability. Though the challenge did not affect the adhesion of any eosinophils subtypes, the direct dependence of rEOS and iEOS survivability on their interaction with ASM cells was revealed (p < 0.05). These findings provide the premise for eosinophils subtype-oriented asthma treatment.

Development of Eosinophilic Temporal Arteritis and Digital Ischemia in a Patient with Hypereosinophilic Syndrome

We describe a case of eosinophilic temporal arteritis in a 61-year-old woman with hypereosinophilic syndrome, who developed subcutaneous nodules in the temporal areas and digital cyanosis with small nodules on the sides of her fingers. Ultrasound revealed occlusion and corkscrew-like changes of the temporal and digital arteries, respectively. Temporal artery biopsy revealed eosinophilic vasculitis without giant cell formation. Angiography showed occlusion of the ulnar and digital arteries. Administration of low-dose corticosteroid improved the temporal artery swelling and digital cyanosis. More reports of similar cases are required to characterize this type of non-giant cell eosinophilic vasculitis that affects the peripheral arteries.

Idiopathic Hypereosinophilia and Venous Thromboembolism: Is There a Pathophysiological or Clinical Link? Description of an Intriguing Clinical Case

Thrombosis events usually occur after prolonged bedrest, pregnancy, hormonal therapy, recent surgery and in the presence of inherited or acquired thrombophilia. However, several other diseases are often associated with thrombosis although their frequency is not easily estimated. Eosinophilia is one of these conditions. From a clinical viewpoint it is very difficult to understand which conditions might lead to a thrombotic event because the underlying pathophysiological mechanisms are different. Here, we report a case of idiopathic hypereosinophilia associated to venous thromboembolism without any other associated prothrombotic condition.