Spectrum of Eosinophilic End-Organ Manifestations

Differential roles of eosinophils in cardiovascular disease

Eosinophils are essential innate immune cells in allergic responses. Accumulating evidence indicates that eosinophils also participate in the pathogenesis of cardiovascular diseases (CVDs). In clinical studies, high blood eosinophil counts and eosinophil cationic protein levels have been associated with an increased risk of CVD, including myocardial infarction (MI), cardiac hypertrophy, atrial fibrillation, abdominal aortic aneurysm (AAA) and atherosclerosis. However, low blood eosinophil counts have also been reported to be a risk factor for MI, heart failure, aortic dissection, AAA, deep vein thrombosis, pulmonary embolism and ischaemic stroke. Although these conflicting clinical observations remain unexplained, CVD status, timing of eosinophil data collection, and tissue eosinophil phenotypic and functional heterogeneities might account for these discrepancies. Preclinical studies suggest that eosinophils have protective actions in MI, cardiac hypertrophy, heart failure and AAA. By contrast, cationic proteins and platelet-activating factor from eosinophils have been shown to promote vascular smooth muscle cell proliferation, vascular calcification, thrombomodulin inactivation and platelet activation and aggregation, thereby exacerbating atherosclerosis, atrial fibrillation, thrombosis and associated complications. Therefore, eosinophils seem to promote calcification and thrombosis in chronic CVD but are protective in acute cardiovascular settings. In this Review, we summarize the available clinical and preclinical data on the different roles of eosinophils in CVD.

Chronic eosinophilic leukaemia-Not otherwise specified: Clinical features, genomic insight and therapeutic strategies

Chronic eosinophilia leukaemia-not otherwise specified (CEL-NOS) is a rare myeloproliferative neoplasm characterized by persistent clonal hypereosinophilia. Recent advances in genetics have refined diagnostic criteria, leading to the identification of CEL subtypes with specific cytogenetic and molecular abnormalities now classified as myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions, which may benefit from targeted therapies. In contrast, CEL-NOS lacks specific genetic drivers and intervention points to halt leukemogenesis. Molecular techniques have also enabled the definition of clonality in a considerable percentage of cases otherwise classified as idiopathic hypereosinophilic syndrome. CEL-NOS poses a significant therapeutic challenge due to limited treatment options, poor prognosis and the risk of progression to acute leukaemia. Patients, often elderly and with comorbidities, face restricted access to transplantation, the only potentially curative treatment. Unfortunately, the prognosis remains poor even post-transplant, with a 5-year survival rate of only one-third of patients. Other therapies, including steroids, cytoreductive and immunomodulatory treatments, offer limited and temporary responses with significant side effects. This review aims to consolidate current knowledge on CEL-NOS, covering diagnostic approaches, genetic advancements and therapeutic challenges. It seeks to provide a comprehensive overview and highlight critical areas for future research.

Refractory Idiopathic Hypereosinophilic Syndrome Presenting with Myocarditis and Responding to Imatinib: A Case Report

Idiopathic hypereosinophilic syndrome (HES) is a rare disorder characterized by persistent hypereosinophilia leading to multi-organ dysfunction. Its clinical manifestations vary widely; however, cardiac and neurological involvement are the leading causes of morbidity and mortality. Corticosteroids are the initial treatment of choice, but in idiopathic HES resistant to corticosteroids, second-line therapy should be considered. Imatinib is usually reserved for patients with a positive platelet-derived growth factor receptor A (PDGFR-A) mutation; however, its use in idiopathic HES with a negative PDGFR mutation is debatable given that such patients usually respond well to high doses of corticosteroids. Here, we present a case of a young male with corticosteroid-refractory idiopathic HES successfully treated with imatinib. The patient presented with features suggestive of acute coronary syndrome and confusion. A coronary angiogram was normal. Echocardiography showed an ejection fraction of 37%, and brain imaging showed evidence of multifocal cerebral thromboembolic infarcts. During the hospital stay, the patient developed diffuse alveolar hemorrhage. Biochemically, it was noted that the patient had hypereosinophilia. Through thorough workup, a diagnosis of idiopathic HES was established. The patient was started on high-dose corticosteroid (500 mg intravenous methylprednisolone daily) followed by a maintenance dose of prednisolone (0.5 mg/kg/day), but had no response. Second-line therapy with imatinib (400 mg per oral daily for 4 days and then down-titrated to 100 mg daily) was initiated, which resulted in drastic biochemical and clinical improvements. This case report supports the efficacy of imatinib as a second-line agent in corticosteroid-resistant idiopathic HES with a negative PDGFR mutation.

Cardiac Abnormalities in Hypereosinophilic Syndromes

Hypereosinophilia (HE) is defined as an eosinophil count exceeding 1500 cells/microL in peripheral blood in two tests, performed with an interval of at least one month and/or anatomopathological confirmation of HE, with eosinophils comprising more than 20% of all nucleated cells in the bone marrow. Hypereosinophilic syndrome (HES) indicates the presence of HE with organ involvement due to eosinophil action, which can be classified as primary (or neoplastic), secondary (or reactive), and idiopathic. Cardiac involvement occurs in up to 5% of cases in the acute phase and 20% of the chronic phase of the disease, ranging from oligosymptomatic cases to fulminant acute myocarditis or chronic restrictive cardiomyopathy (Loeffler endomyocarditis). However, the degree of cardiac dysfunction does not directly correlate with the degree of eosinophilia. The cardiac involvement of HES occurs in three phases: initial necrotic, thrombotic, and finally necrotic. It can manifest as heart failure, arrhythmias, and thromboembolic phenomena. The diagnosis of cardiopathy is based on multimodality imaging, with an emphasis on the importance of echocardiography (echo) as the primary examination. TTE with enhanced ultrasound agents can be used for better visualization, allowing greater accuracy in assessing ventricular apex, and myocardial deformation indices, such as longitudinal strain, may be reduced, especially in the ventricular apex (reverse apical sparing). Cardiac magnetic resonance imaging allows the characterization of subendocardial late gadolinium enhancement, and endomyocardial biopsy is considered the gold standard in diagnosing cardiopathy. Treatment is based on the etiology of HES.

Incessant Ventricular Tachycardia: An Atypical Presentation of Chronic Eosinophilic Leukemia

Hypereosinophilic syndrome comprises a diverse and intricate array of rare disorders, exhibiting clinical manifestations that extend across various medical subspecialties. Within its myeloid form, chronic eosinophilic leukemia represents a rare myeloid malignancy characterized by severe hematological complications and distinctive organ dysfunction, notably affecting the cardiovascular system. This report presents a rare case of chronic eosinophilic leukemia and Loeffler syndrome with an initial presentation of ventricular tachycardia.

Biologic therapy in rare eosinophil-associated disorders: remaining questions and translational research opportunities

Rare eosinophil-associated disorders (EADs), including hypereosinophilic syndrome, eosinophilic granulomatosis with polyangiitis, and eosinophilic gastrointestinal disorders, are a heterogeneous group of conditions characterized by blood and/or tissue hypereosinophilia and eosinophil-related clinical manifestations. Although the recent availability of biologic therapies that directly and indirectly target eosinophils has the potential to dramatically improve treatment options for all EADs, clinical trials addressing their safety and efficacy in rare EADs have been relatively few. Consequently, patient access to therapy is limited for many biologics, and the establishment of evidence-based treatment guidelines has been extremely difficult. In this regard, multicenter retrospective collaborative studies focusing on disease manifestations and treatment responses in rare EADs have provided invaluable data for physicians managing patients with these conditions and helped identify important questions for future translational research. During the Clinical Pre-Meeting Workshop held in association with the July 2023 biennial meeting of the International Eosinophil Society in Hamilton, Ontario, Canada, the successes and limitations of pivotal multicenter retrospective studies in EADs were summarized and unmet needs regarding the establishment of guidelines for use of biologics in rare EADs were discussed. Key topics of interest included (1) clinical outcome measures, (2) minimally invasive biomarkers of disease activity, (3) predictors of response to biologic agents, and (4) long-term safety of eosinophil depletion. Herein, we report a summary of these discussions, presenting a state-of-the-art overview of data currently available for each of these topics, the limitations of the data, and avenues for future data generation through implementation of multidisciplinary and multicenter studies.

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.

Clinical Characteristics of EGPA Patients in Comparison to GPA Subgroup with Increased Blood Eosinophilia from POLVAS Registry

Objective

To characterize the eosinophilic granulomatosis with polyangiitis (EGPA) population from the POLVAS registry depending on ANCA status and diagnosis onset, including their comparison with the granulomatosis with polyangiitis (GPA) subset with elevated blood eosinophilia (min. 400/μl) (GPA HE) to develop a differentiating strategy.

Methods

A retrospective analysis of the POLVAS registry.

Results

The EGPA group comprised 111 patients. The ANCA-positive subset (n = 45 [40.54%]) did not differ from the ANCA-negative one in clinics. Nevertheless, cardiovascular manifestations were more common in ANCA-negative patients than in those with anti-myeloperoxidase (MPO) antibodies (46.97% vs. 26.92%, p = 0.045). Patients diagnosed before 2012 (n = 70 [63.06%]) were younger (median 41 vs. 49 years, p  < 0.01), had higher blood eosinophilia at diagnosis (median 4,946 vs. 3,200/μl, p  < 0.01), and more often ear/nose/throat (ENT) and cardiovascular involvement. GPA HE comprised 42 (13.00%) out of 323 GPA cases with reported blood eosinophil count. Both GPA subsets had a lower prevalence of respiratory, cardiovascular, and neurologic manifestations but more often renal and ocular involvement than EGPA. EGPA also had cutaneous and gastrointestinal signs more often than GPA with normal blood eosinophilia (GPA NE) but not GPA HE. The model differentiating EGPA from GPA HE, using ANCA status and clinical manifestations, had an AUC of 0.92, sensitivity of 96%, and specificity of 95%.

Conclusion

Cardiovascular symptoms were more prevalent in the ANCA-negative subset than in the MPO-ANCA-positive one. Since EGPA and GPE HE share similarities in clinics, diagnostic misleading may result in an inappropriate therapeutic approach. Further studies are needed to optimize their differentiation and tailored therapy, including biologics.

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.

Association Between Elevated Blood Eosinophils and Chronic Kidney Disease Progression: Analyses of a Large United States Electronic Health Records Database

Background

Blood eosinophils can increase in response to infection, inflammation, and hypersensitivity reactions, yet their involvement in the progression of chronic kidney disease (CKD) is poorly understood. This study explores the relationship between blood eosinophils and CKD progression among patients in a real-world setting.

Methods

This retrospective study analyzed data obtained from the Optum® de-identified electronic health records dataset in the United States. Patients diagnosed with CKD stage 3 or 4 (International Classification of Diseases diagnosis code or estimated glomerular filtration rate [eGFR] <60 mL/min) between January 2011 and March 2018 were included and followed until progression to the next CKD stage, death, or dropout. The primary objective of this study was to assess the relationship between blood eosinophil counts (bEOS) and CKD progression, adjusting for clinical and demographic features as well as known risk factors for CKD stages 3-4. The primary outcomes were CKD progression and all-cause mortality.

Results

We found that high eosinophilic levels (bEOS ≥300 cells/µL) were associated with CKD progression from stage 3 to stages 4 or 5 (hazard ratio [HR] ranging from 1.30 to 1.50) and from stages 4 to 5 (HR ranging from 1.28 to 1.50). Among patients with CKD progression, those with blood eosinophils ≥300 cells/µL appeared to have a relatively lower eGFR, higher all-cause mortality, and reduced time to CKD progression and death than those with <300 cells/µL. Factors including sex, race, hypertension, anemia, and treatments for cardiovascular and hematopoietic drugs were associated with CKD progression.

Conclusion

Elevated eosinophils may increase the risk for CKD progression. Larger studies are needed to assess whether the risk of mortality is increased among patients with elevated eosinophils.

Hypereosinophilic syndrome associated with multiple thromboses requiring ICU admission: A case report

Hypereosinophilic syndrome (HES) is a leucoproliferative disorder, characterized by marked blood eosinophilia and organ damage due to tissue eosinophilia. Pulmonary involvement may lead to life-threatening acute respiratory failure and intensive care unit (ICU) admission. Association between eosinophilia and thromboembolism has been previously described. However, simultaneous venous and arterial thromboses are less reported. We report a case of a 25-year-old man, admitted to the ICU and developed acute respiratory failure, laboratory tests revealed hyperleukocytosis (39,700 /µL) with high eosinophil count (27393 /µl), Computed tomographic (CT) pulmonary angiography on admission showed a right pulmonary embolism and foci of splenic infarctions. Echocardiography showed a thrombus in the ascending aorta. On day 3, the patient presented worsening polypnea with increase of oxygen requirements. Chest CT scan showed pulmonary parenchymal involvement with bilateral condensations surrounded by "tree-in-bud" micronodules. The diagnosis of eosinophilic pneumonia was established. Bone marrow biopsy showed hyperplasia of the 3 lineages, predominant on the granulocyte lineage made mostly of eosinophilic polynuclear mature cells, suggesting myeloproliferative syndrome. The patient was treated with corticosteroids and anticoagulation. Physicians should consider HES diagnosis in case of hypereosinophilia and evolving life threatening organ damage to avoid therapy delay and complications.

Case report: Lymphocytic-plasmacytic and eosinophilic enterocolitis presented with marked eosinophilia and basophilia in a cat

Inflammatory bowel disease is a common condition in cats, characterized by recurring gastrointestinal signs with histologic evidence of intestinal inflammation. A 9-month-old neutered male Sphynx cat was presented with a 5-week history of vomiting and hematochezia. Conservative patient management with a therapeutic gastrointestinal formula, antibiotics, and antiemetics resulted in a positive response to treatment, with relapse of signs when the medications were discontinued. A new finding of marked eosinophilia and basophilia was identified 3 months after the initial presentation. Colonoscopy revealed cecal erosions and a surgical biopsy with histopathology confirmed a diagnosis of lymphocytic-plasmacytic and eosinophilic enterocolitis. For this diagnosis, the patient was treated with prednisolone, tylosin, and metronidazole. Antibiotics were gradually tapered as the cat showed clinical improvement. The patient showed resolution of the gastrointestinal signs, and the numbers of eosinophils and basophils returned within the reference range 8 weeks after the treatment began. Basophilia and eosinophilia has been reported in conjunction with feline T-cell lymphoma. However, marked basophilia accompanying eosinophilia is extremely rare in cats with inflammatory bowel disease. We herein provide clinical details, including ultrasonography, endoscopy, histopathology, and disease course of feline lymphocytic-plasmacytic and eosinophilic enterocolitis with marked basophilia and eosinophilia. This case highlights the importance of considering enteritis as potential diagnoses when eosinophilia and basophilia are concurrently observed in cats.

Therapeutic Advances in Eosinophilic Granulomatosis with Polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA) is an eosinophilic vasculitis that affects a variety of organ systems. Historically, glucocorticoids and a variety of other immunosuppressants were used to abrogate the inflammation and tissue injury associated with EGPA. The management of EGPA has evolved greatly during the last decade with the development of novel targeted therapeutics that have resulted in significantly improved outcomes for these patients, with many more novel targeted therapies emerging.

Unmet needs and evidence gaps in hypereosinophilic syndrome and eosinophilic granulomatosis with polyangiitis

Hypereosinophilic syndrome (HES) and eosinophilic granulomatosis with polyangiitis (EGPA) are rare systemic inflammatory disorders with overlapping symptoms, elevated eosinophil counts, and heterogenous clinical presentations. Although progress has been made in recent years, there are substantial gaps in our understanding of the pathologic mechanisms involved in these diseases, as well as numerous unmet needs relating to both diagnosis and patient management. For example, in most cases of HES, the underlying cause of hypereosinophilia is unknown, while in EGPA, although a polygenic genetic susceptibility has been found, understanding of the pathogenic mechanisms remains largely elusive. Delineating differences between certain disease variants may be challenging, and there are no reliable predictive markers of disease course. In addition, the current diagnostic criteria for HES and classification criteria for EGPA are not easy to implement in a nonspecialist setting, and specialist referral pathways need to be signposted more clearly. Furthermore, disease-specific activity scores need to be developed to aid the assessment of treatment effects, and improved biomarkers are needed to aid with treatment stratification. In this review, we outline the limitations of our current understanding of HES and EGPA and highlight areas for future work, which ultimately should help improve patient management and outcomes.

Development of Henoch-Schoenlein purpura in a child with idiopathic hypereosinophilia syndrome with multiple thrombotic onset: A case report

BACKGROUND

The incidence of pulmonary embolism (PE) in children is low, but its mortality is high. Hypereosinophilic syndrome (HES) is a group of diseases caused by an abnormal increase in eosinophilic granulocytes resulting in multiple-organ dysfunction. The urgent event of thromboembolism in the pulmonary region provoked by eosinophils in idiopathic HES (IHES) is relatively unusual. This article reports a case of IHES with multiple PEs and left leg venous thrombosis as the first manifestation. One month later, the patient developed Henoch-Schonlein purpura (HSP), which is very rare.

CASE SUMMARY

We report the case of a 12-year-old boy who was admitted to the hospital with dyspnea, left leg pain, and aggravation. He had bilateral PE and left leg venous embolism with mild eosinophilia. Low-molecular-weight heparin and urokinase were given. At the same time, the interventional department was contacted about filter implantation, followed by urokinase thrombolysis. The left leg thrombus was aspirated under ultrasound guidance. He was discharged from the hospital on rivaroxaban. One month later, he developed a rash on both legs and ankle pain consistent with HSP, with severe eosinophilia and motor and sensory disturbances. The patient was diagnosed with IHES with multiple embolisms complicated by HSP after excluding other causes of the eosinophil elevation. After glucocorticoid treatment, the symptoms were relieved, but the patient later developed purpura nephritis.

CONCLUSION

We report a rare and life-threatening case of IHES with multiple embolisms associated with HSP. A mild elevation of eosinophils early in the disease leads to difficulties in diagnosis and delayed treatment.

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.

Chronic Eosinophilic Leukemia Presenting as Cardiac Failure

Chronic eosinophilic leukemia (CEL) is a rare chronic myeloproliferative disorder characterized by sustained eosinophilia. Although the incidence of CEL is uncertain, it can be clinically devastating as it has a propensity to affect several important organ systems. This is of particular significance in Sub-Saharan Africa where helminthic infections are a more prevalent cause of eosinophilia. To the best of our knowledge, we present the first reported case of CEL complicated by cardiac disease in a Ghanaian. He presented with a history of orthopnoea and dyspnoea on exertion, and examination revealed a pansystolic murmur over the mitral region and moderate splenomegaly. Good symptomatic control was achieved using hydroxyurea after which haematologic and cytogenetic remission was achieved after 12 weeks on a tyrosine kinase inhibitor. Physicians working in low resource environments should exclude clonality in patients presenting with eosinophilia and end-organ damage.

Clopidogrel-induced Eosinophilia with Hypercalcemia

There are few cases describing the association of eosinophilia with hypercalcemia, and drug-induced eosinophilia with hypercalcemia has not been reported. A 74-year-old man had been diagnosed with asthma 4 months earlier. He was admitted due to eosinophilia with hypercalcemia. Chest computed tomography showed a nodule in the left lung and mediastinal lymphadenopathy. By obtaining a detailed medical history, clopidogrel was suspected as the prime cause of eosinophilia. After the discontinuation of clopidogrel, the eosinophilia with hypercalcemia, lung nodule and mediastinal lymphadenopathy improved. Clopidogrel-induced eosinophilia can potentially cause hypercalcemia. Obtaining a detailed clinical history is important in diagnosing the cause of eosinophilia.

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.

Dupilumab-induced hypereosinophilia: review of the literature and algorithm proposal for clinical management

INTRODUCTION

Dupilumab is a human monoclonal antibody that targets both IL-4 and IL-13 signaling. It is currently indicated for the treatment of asthma, moderate-to-severe atopic dermatitis, and chronic rhinosinusitis with nasal polyps (CRSwNP). Eosinophilia has been reported as a potential adverse event in treated patients.

AREAS COVERED

A selective search on PubMed and Medline up to January 2022 was performed, by focusing on dupilumab-induced hypereosinophilia described in clinical trials, real-life studies, and case reports. The possible mechanisms underlying dupilumab-induced hypereosinophilia and the eosinophil-related morbidity have also been explored.

EXPERT OPINION

Dealing with dupilumab-induced hypereosinophilia represents a clinical challenge for clinicians managing patients on dupilumab therapy. An algorithm for the practical management of dupilumab-induced hypereosinophilia has been proposed, in order to properly investigate potential eosinophil-related morbidity and avoid unnecessary drug discontinuation.

[Cutaneous manifestation of lymphoid variant of hypereosinophilic syndrome: One case]

INTRODUCTION

Lymphoid hypereosinophilic syndrome (HES) is a reactive HES, related to the presence of an abnormal circulating T cell clone. Cutaneous manifestations are frequent and sometimes inaugural, however few studies describe them specifically.

CASE REPORT

We report the case of a 63-year old patient, in good general condition, with no previous history and taking no treatment, who was being followed for non-specific skin lesions. Blood and skin examinations showed hypereosinophilia, the presence of an aberrant CD3-CD4+ phenotype and a positive T-clonality test. There was no differential diagnosis or argument for a systemic lymphoma.

CONCLUSION

Cutaneous manifestations of lymphoid HES are variable, non-specific, and may differ according to lymphocyte phenotype. The discovery of SHE requires an extension workup and the risk of evolution towards a systemic lymphoma justifies a close surveillance. Treatment is adapted to the severity of the symptoms.

Pregnant lady with eosinophilia: common cause, uncommon association

Peripheral eosinophilia can have a myriad of causes and presents a diagnostic challenge in everyday practice. Tropical pulmonary eosinophilia (TPE), seen commonly in tropics, is an immunological reaction to filarial parasites. This disease can present with clinical features that closely mimic asthma, eosinophilic pneumonia, and Loffler's syndrome. Differentiating between these diseases is essential owing to marked differences in treatment. This can be further challenging in pregnancy as any wrong treatment is likely to affect both the mother and the child. We report a case of a pregnant lady who presented with eosinophilia and of how she was worked up to the correct diagnosis. There are only few reported cases of TPE in pregnancy, and there are no reported cases from India. The case also underlines the approach required in these patients to reach the correct diagnosis.

Eosinophilic gastrointestinal disorders and allergen immunotherapy: Lights and shadows

Allergic diseases, such as IgE-mediated food allergy, asthma, and allergic rhinitis, are relevant health problems worldwide and show an increasing prevalence. Therapies for food allergies are food avoidance and the prompt administration of intramuscular epinephrine in anaphylaxis occurring after accidental exposure. However, allergen immunotherapy (AIT) is being investigated as a new potential tool for treating severe food allergies. Effective oral immunotherapy (OIT) and epicutaneous immunotherapy (EPIT) induce desensitization and restore immune tolerance to the causal allergen. While immediate side effects are well known, the long-term effects of food AIT are still underestimated. In this regard, eosinophilic gastrointestinal disorders (EGIDs), mainly eosinophilic esophagitis, have been reported as putative complications of OIT for food allergy and sublingual immunotherapy (SLIT) for allergic asthma and rhinitis. Fortunately, these complications are usually reversible and the patient recovers after AIT discontinuation. This review summarizes current knowledge on the possible causative link between eosinophilic gastrointestinal disorders and AIT, highlighting recent evidence and controversies.

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.

B-acute Lymphoblastic Leukemia With Hypereosinophilia Associated With Severe Cardiac Complications: A Clinical Case

Hypereosinophilia (HE) is rare but often secondary to a nonhematologic disease such as allergic disorders and parasitic infections. HE can also be associated with hematologic malignancies and be the result of a clonal proliferation or reactive to another hematologic condition. Association of HE with acute lymphoblastic leukemia (ALL) is rare in children. We reported a case of a teenager presented with HE secondary to B-ALL who experienced severe cardiac complications with severe absolute eosinophil count. We compared his clinical evolution with other published cases and we reported 2 mutations linked to B-ALL never described before in this context.

Mepolizumab as a glucocorticoid-sparing agent in eosinophilic granulomatosis with polyangiitis (EGPA): is a lower dose sufficient?

INTRODUCTION

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare form of small-vessel vasculitis characterized by asthma, hyper-eosinophilia, and progressive multiorgan involvement. EGPA is traditionally treated using glucocorticoids, either alone or in combination with conventional immunosuppressants. Mepolizumab, a novel anti-interleukin (IL)-5 agent, has been approved as an add-on therapy for adult patients with EGPA. The recommended dose of mepolizumab is 300 mg (subcutaneous [SC]) every 4 weeks.

CASE STUDY

The present report discusses three cases of refractory and/or relapsing EGPA in patients regularly taking a stable dose of prednisolone, all of whom were successfully treated with a lower-than-recommended dose of mepolizumab (100 mg SC, every 4 weeks).

RESULTS

Treatment with a low dose of mepolizumab enabled us to gradually reduce glucocorticoid doses. In addition, patients treated with low doses of mepolizumab exhibited better asthma control and experienced sustained relapse-free periods. Responses to 100 mg of mepolizumab were comparable to those previously observed in patients taking the recommended dose of 300 mg.

CONCLUSION

Our findings suggest that mepolizumab at a third of the recommended dose can achieve reasonable clinical efficacy in the long-term treatment of EGPA in some patients. Initiation of mepolizumab therapy in the early, eosinophilic phase of EGPA-which is characterized by asthma, marked blood eosinophilia, pulmonary infiltrates, and sinonasal abnormalities-may help to prevent the deleterious side-effects of long-term glucocorticoid use while reducing the cost of EGPA treatment.

Targeted FGFR inhibition results in a durable remission in an FGFR1-driven myeloid neoplasm with eosinophilia

A novel PCM1 -FGFR1 gene rearrangement was identified in a patient with a myeloid neoplasm with eosinophilia. Futibatinib, an oral selective small molecule inhibitor of FGFR1-4, resulted in a durable complete hematologic and cytogenetic remission.

Loeffler's Endocarditis and Hypereosinophilic Syndrome

Loeffler's endocarditis and hypereosinophilic syndromes are a unique group of infiltrative disorders characterized by hypereosinophilia, inflammatory thrombotic, and ultimately, fibrotic involvement of the heart leading to multiple complications including valve involvement, thromboembolic phenomena, heart failure. Clinical recognition, comprehensive laboratory and multimodality imaging diagnostic workup, and early initiation of treatment have been shown to slow down the progression and promote remission. This review addresses a detailed analysis of Loeffler's endocarditis and hypereosinophilic syndromes.

A case of suspected eosinophilic myocarditis recognized by a fully noninvasive approach and safely treated with corticosteroids despite underlying hepatitis C virus-related hepatitis

Hypereosinophilic syndrome can lead to acute myocarditis with a potentially severe systolic dysfunction and serious complications. A 75-year-old patient suffering from Hepatitis C virus (HCV) related-hepatitis came to our observation for idiopatic hypereosinophilic syndrome and acute severe cardiac systolic dysfunction without coronaropathy. Cardiac magnetic resonance showed a 'patchy' subendocardial and intramyocardial late gadolinium enhancement pattern often seen in eosinophilic myocarditis (EM). Assuming EM, appropriate corticosteroid therapy was initiated and it led to clinical remission. Despite endomyocardial biopsy (EMB) is the diagnostic gold standard for EM, in this case only a noninvasive integrated imaging approach was successfully attempted. Given an adequate clinical context, in our opinion EM can be correctly recognized without EMB and so promptly and safely treated with corticosteroids, even when an underling mild HCV-hepatitis is present.

Practical Approach to Children Presenting with Eosinophila and Hypereosinophilia

Eosinophilia is not a rare finding in clinical practice, and often poses problems in terms of etiologic research and differential diagnosis. Peripheral eosinophilia is defined by a blood eosinophil count > 500 cells/μL. It is classified into mild (500-1500 cells/μl), moderate (1500-5000 cells/μl) and severe for an eosinophil count > 5000 cells /μl. The term "hypereosinophilia" defines a condition characterized by a blood eosinophil count >1500 cells/μl in at least two consecutive tests made with a minimum of a 4-week interval. The causes of eosinophilia are various, and can be summarized by the acronym "APLV" which refers to Allergic disorders, Parasitic infections, Leukemia/ Lymphomas (and solid tumors) and Vasculitis-Immunodeficiency diseases, with allergic disorders and parasitic infections representing the most commonly identified causes. Allergic disorders are usually associated with mild eosinophilia, whereas values >20.000 cell/μl are highly suggestive for myeloproliferative disorders. Eosinophils may also be directly responsible for organ damage, mainly at cardiac, pulmonary and cutaneous level, deriving from the release of the granule products, of lipidic mediators and cytokines. Therefore, in the physician's approach to a patient with persistent hypereosinophilia, it is also important to investigate the presence of organ involvement. In this review, we propose a diagnostic algorithm for children presenting with either blood eosinophilia or hypereosinophilia. This algorithm focuses on the patient's history and clinical manifestations as the first step and the level and persistence of blood eosinophilia as the second, and this can help the physician to identify patients presenting with an elevated blood eosinophil count that need further laboratory or instrumental investigations.

Mitral and tricuspid valve repair in hypereosinophilic syndrome

Hypereosinophilic syndrome (HES) is a rare systemic condition, defined as a persistently elevated eosinophil count associated with end organ damage and the absence of a primary cause. Cardiac involvement occurs in about 50% of patients with HES. Myocardial infiltration results in endomyocardial fibrosis, valve dysfunction and mural thrombus. The atrioventricular valves are almost always involved, resulting in regurgitation due to leaflet restriction, most commonly affecting the posterior mitral valve leaflet. Surgical management remains challenging in patients with HES with limited data on the choice of valve surgery. We describe the case of a 17-year-old woman with HES complicated by congestive cardiac failure secondary to severe mitral and tricuspid regurgitation. Because of refractory heart failure despite medical therapy, surgical mitral and tricuspid valve repair was performed, and an excellent 24-month outcome was achieved. We believe this is the first report of double valve repair in this rare condition.

Idiopathic hypereosinophilic syndrome presenting with multiple organ damage: A case report

RATIONALE

Idiopathic hypereosinophilic syndrome (IHES) is a rare disease in which patients which present with eosinophilia-associated damage. Previous studies focused on organ damage from increased eosinophilic granulocytosis. We report IHES in a patient who presented with multiple organ damage (MOD).

PATIENT CONCERNS

A 52-year-old male presented with MOD, including myocardial damage suggestive of myocardial infarction, cardiac tamponade, respiratory failure, skin damage, and gastrointestinal damage.

DIAGNOSES

The absolute eosinophil count was 12,920/mm, much higher than occurs in other diseases associated with eosinophilia (1500/mm), and suggesting a diagnosis of IHES.

INTERVENTIONS

Prednisone combined with hydroxyurea.

OUTCOMES

At 6 months after completion of drug treatment, the patient had no chest pain or dyspnea, and the results of a blood panel, chest computed tomography, and gastroscopy were normal.

LESSONS

MOD is very rare in patients with IHES. Patients receiving prompt diagnosis and treatment have very good prognoses.

Thrombotic microangiopathy in a patient with eosinophilic granulomatosis with polyangiitis: case-based review

The correct diagnosis, classification and therapeutic management of thrombotic microangiopathies (TMA) continue to be a challenge for the clinician. We report a rare case of eosinophilic granulomatosis with polyangiitis (EGPA) as a trigger for complement-mediated TMA in a 57-year-old man who was successfully treated with corticoids, cyclophosphamide and therapeutic plasma exchange. Additionally, we review few other cases reported in the literature and the pathophysiological pathway of association between TMA and EGPA. We found that the mutual relationships between the inflammation triggered by vasculitis, the exacerbated complement activation, together with hypereosinophilia and endothelial damage seem to be the key in explaining the connection between both entities. We suggest that an understanding of the multi-causal nature of TMAs is crucial for the correct diagnosis and treatment of these patients.

Eosinophilic Granulomatosis with Polyangiitis (EGPA) with an Unusual Manifestation of Mid-Ventricular Obstruction Caused by Endocardial Thrombus

Patient: Male, 46

Final Diagnosis: Eosinophilic granulomatosis with polyangiitis

Symptoms: Chest pain

Medication: —

Clinical Procedure: Skin biopsy

Specialty: Cardiology

Acute pulmonary embolism and deep vein thrombosis secondary to idiopathic hypereosinophilic syndrome

Acute pulmonary embolism (PE) is a most dangerous complication that needs prompt treatment to reduce potentially death. There are many well-known prognostic factors indicate the morbidity and mortality in various thromboembolic events. Persistent eosinophilia in peripheral blood can lead to tissue infiltration and even organ damage, but the urgent event of thromboembolism in pulmonary provoked by eosinophil eosinophilia in idiopathic hypereosinophilic syndrome (HES) is relative an unusual presentation. In this paper, we present two cases of patients with multiple PE and deep vein thrombosis secondary to the idiopathic HES. Patients were all treated using anticoagulant therapy and corticosteroids successfully. Accordingly, eosinophilia is another risk and precipitating factor of pulmonary thromboembolism. It is necessary for physicians to make a diagnosis in hypereosinophilia as soon as possible for proper prognosis and in case of further thromboembolic events and prevent end-organ damage.

Loeffler endocarditis as a rare cause of heart failure with preserved ejection fraction: A case report and review of literature

RATIONALE

Hypereosinophilic syndrome (HES) is a rare disease characterized by hypereosinophilia and its ensuing organ damage. Cardiac involvement is divided into 3 chronological stages: an acute necrotic stage; a thrombus formation stage; and a fibrotic stage. Infiltration of the myocardium by eosinophilic cells followed by endomyocardial fibrosis is known as "Loeffler endocarditis."

PATIENT CONCERNS

We report a case of a 60-year-old man diagnosed with left-sided restrictive cardiomyopathy.

DIAGNOSIS

The patient experienced heart failure with preserved ejection fraction. The cardiac MRI showed intense, linear, delayed gadolinium enhancement of the endocardium of the lateral wall of the left ventricle, and obliteration of the LV apex. He was ultimately identified as Loeffler endocarditis.

INTERVENTION

A bone marrow smear and biopsy revealed the FIP1L1-PDGFRA fusion gene was positive in 82% of segmented nucleated cells.

OUTCOME

Our patient responded well to prednisone at 1 mg/kg/d.

LESSONS

HES is a rare disease that often afflicts the heart. Cardiac involvement in hypereosinophilia, especially Loeffler endocarditis, carries a poor prognosis and significant mortality. Early detection and treatment of the disease is therefore essential. Further studies are needed to ascertain therapeutic corticosteroid dosages and develop targeted gene therapies, both important steps to ameliorate the effects of Loeffler endocarditis and improve patient outcomes.

Hypereosinophilic syndrome with central nervous system involvement: Two case reports and literature review

OBJECTIVE

To report two cases of hypereosinophilic syndrome (HES) with central nervous system involvement and explore its possible pathogenesis.

METHODS

We have analysed the clinical data and relevant features of two patients who presented themselves to The Affiliated Hospital of Xuzhou Medical University between 2012 and 2015. We have reviewed the relevant literature, elaborated the possible pathogenesis, and discussed the treatment options.

RESULTS

Both patients had consistently high levels of absolute eosinophil count which led to multiple cerebral infarcts in the arterial border zone and small-vessel disease. Blood tests were taken several times during their course of disease showing elevated eosinophils. Both patients underwent head computed tomography (CT), magnetic resonance imaging, and magnetic resonance angiography, which indicated small-vessel disease and watershed infarction. Glucocorticoids, improvement cycle, and neuro-nutrition treatments resulted in a significant improvement of their clinical state.

CONCLUSION

HES can involve central nervous system by causing small-vessel disease and watershed infarction, which can be its presenting features. Repeated blood tests should be done to rule out HES in central nervous system lesion.

Eosinophilic sialodochitis: redefinition of 'allergic parotitis' and 'sialodochitis fibrinosa'

Sialodochitis fibrinosa and allergic parotitis have described rare patients with recurrent salivary gland swelling and mucus plugs, often with atopy. We have evaluated three patients with atopic disease, recurrent salivary gland swelling, and an eosinophilic sialodochitis. Two had eosinophil-rich mucus plugs. Fifty-six additional cases were identified in a medical literature database search, each defined by recurrent salivary gland swelling associated with eosinophil-rich mucus plugs or sialodochitis with periductal eosinophilic infiltration. The majority (78%) were reported from Japan. Females were predominantly affected (F:M = 2.3) with a median age of 47 years at evaluation. The parotid and submandibular glands were involved, respectively, in 71% and 46%. Allergic symptoms were present in 66%, atopic disease in 63% of those with reported allergy testing, and blood eosinophilia in 71%. Contrast sialography and other imaging modalities documented ductal dilatation in 82%. Treatments included anti-allergic medications (58%), systemic glucocorticoids (25%), duct cannulation with irrigation, steroid injection, and/or duct dilatation (36%), and glandular resection (19%). We recommend the diagnosis 'eosinophilic sialodochitis' be applied to patients who meet this case definition. The disease is a unique cause of chronic recurrent salivary gland swelling. Its likely allergic etiology may be amenable to current or future biologic therapies.

[Clinical approach to imported eosinophilia]

Eosinophilia is a common finding in international travelers and immigrants, being an helmintic infection its main etiology. The positive predictive value of eosinophilia for an helmintosis is low in travellers. Eosinophilia may be an incidental finding, or symptomatic, and it represents a clinical challenge due to the low sensitivity and specificity of direct and indirect parasitological diagnostic tests, respectively. It requires a structured approach based on geographical areas, environmental exposures and behavioral risks, and associated symptoms. The initial assessment should include a comprehensive and tailored anamnesis and physical examination, basic laboratory tests, a complete parasitological examination of stool samples and a Strongyloides stercoralis serology, supplemented with other explorations guided by epidemiological and clinical suspicion. Empiric treatment with albendazole and/or ivermectin (plus praziquantel if risk of schistosomiasis) is an option for unidentified persistent eosinophilia after study, and in persons in whom a proper assessment or follow-up can not be assured. In patients at risk for estrongiloidosis who are candidates for immunosuppressive therapies, it is indicated a prior screening and treatment to prevent a future hyperinfestation syndrome.

Gene-specific sex effects on eosinophil infiltration in leishmaniasis

Background

Sex influences susceptibility to many infectious diseases, including some manifestations of leishmaniasis. The disease is caused by parasites that enter to the skin and can spread to the lymph nodes, spleen, liver, bone marrow, and sometimes lungs. Parasites induce host defenses including cell infiltration, leading to protective or ineffective inflammation. These responses are often influenced by host genotype and sex. We analyzed the role of sex in the impact of specific gene loci on eosinophil infiltration and its functional relevance.

Methods

We studied the genetic control of infiltration of eosinophils into the inguinal lymph nodes after 8 weeks of Leishmania major infection using mouse strains BALB/c, STS, and recombinant congenic strains CcS-1,-3,-4,-5,-7,-9,-11,-12,-15,-16,-18, and -20, each of which contains a different random set of 12.5% genes from the parental “donor” strain STS and 87.5% genes from the “background” strain BALB/c. Numbers of eosinophils were counted in hematoxylin-eosin-stained sections of the inguinal lymph nodes under a light microscope. Parasite load was determined using PCR-ELISA.

Results

The lymph nodes of resistant STS and susceptible BALB/c mice contained very low and intermediate numbers of eosinophils, respectively. Unexpectedly, eosinophil infiltration in strain CcS-9 exceeded that in BALB/c and STS and was higher in males than in females. We searched for genes controlling high eosinophil infiltration in CcS-9 mice by linkage analysis in F₂ hybrids between BALB/c and CcS-9 and detected four loci controlling eosinophil numbers. Lmr14 (chromosome 2) and Lmr25 (chromosome 5) operate independently from other genes (main effects). Lmr14 functions only in males, the effect of Lmr25 is sex independent. Lmr15 (chromosome 11) and Lmr26 (chromosome 9) operate in cooperation (non-additive interaction) with each other. This interaction was significant in males only, but sex-marker interaction was not significant. Eosinophil infiltration was positively correlated with parasite load in lymph nodes of F₂ hybrids in males, but not in females.

Conclusions

We demonstrated a strong influence of sex on numbers of eosinophils in the lymph nodes after L. major infection and present the first identification of sex-dependent autosomal loci controlling eosinophilic infiltration. The positive correlation between eosinophil infiltration and parasite load in males suggests that this sex-dependent eosinophilic infiltration reflects ineffective inflammation.

Eosinophilic myocarditis and hypereosinophilic syndrome

Hypereosinophilic syndrome (HES) is a heterogeneous group of hematological disorders characterized by a chronic, unexplained hypereosinophilia with tissue damage. Cardiac involvement occurs in ∼20% of patients with HES and represents a major turning point. Cardiac injuries related to eosinophilia are divided into three chronological phases: eosinophilic infiltration, thrombosis, and fibrosis. We report a case of a 33-year-old woman diagnosed with HES, with pulmonary and gastrointestinal involvement and eosinophilic myocarditis in cardiogenic shock. The evolution was favorable with dobutamine, anticoagulation, corticosteroids, and later, β-blockers and angiotensin-converting enzyme inhibitors. Cardiac involvement in HES is rare but carries a poor prognosis. Corticosteroids are considered by many to be the mainstay of treatment. Although new treatments have been suggested, only a few seem promising.