Mortality in hypereosinophilic syndrome: 19 years of experience at Mayo Clinic with a review of the literature

Approach to the patient with eosinophilia in the era of tyrosine kinase inhibitors and biologicals

PURPOSE OF REVIEW

In this review, we aim to explore the optimal approach to patients presenting with eosinophilia, considering recent advances in diagnostic and therapeutic strategies. Specifically, we focus on the integration of novel therapies into clinical practice to improve patient outcomes.

RECENT FINDINGS

Advanced insights into the clinical and genetic features of eosinophilic disorders have prompted revisions in diagnostic criteria by the World Health Organization classification (WHO-HAEM5) and the International Consensus Classification (ICC). These changes reflect a growing understanding of disease pathogenesis and the development of targeted treatment options. The therapeutic landscape now encompasses a range of established and novel therapies. For reactive conditions, drugs targeting the eosinophilopoiesis, such as those aimed at interleukin-5 or its receptor, have demonstrated significant potential in decreasing blood eosinophil levels and minimizing disease flare-ups and relapse. These therapies have the potential to mitigate the side effects commonly associated with prolonged use of oral corticosteroids or immunosuppressants. Myeloid and lymphoid neoplasms with eosinophilia and tyrosine kinase (TK) gene fusions are managed by various TK inhibitors with variable efficacy. Diagnosis and treatment rely on a multidisciplinary approach. By incorporating novel treatment options into clinical practice, physicians across different disciplines involved in the management of eosinophilic disorders can offer more personalized and effective care to patients. However, challenges remain in accurately diagnosing and risk-stratifying patients, as well as in navigating the complexities of treatment selection.

Prognostic factors of idiopathic hypereosinophilic syndrome: A nationwide survey in Japan

Idiopathic hypereosinophilic syndrome (iHES) is a condition wherein persistent hypereosinophilia associated with end-organ damage occurs without any known causes. Due to the rarity of the disease, insufficient knowledge has been accumulated. We therefore conducted a retrospective, multicentre, nationwide survey on iHES in Japan. A total of 57 patients were identified. For 43 patients who received any treatment, all cases were first treated with corticosteroids. An eosinophil percentage of less than 30% in the bone marrow and the absence of oedema were identified as factors associated with steroid dependency. The 5-year overall survival was 88.2%, and five patients died during follow-up; factors associated with worse overall survival were age >50, haemoglobin <12 g/dL, activated partial thromboplastin time >34 s, the presence of dyspnoea, the presence of thrombotic tendency and the presence of renal failure. Given the rarity of fatalities in our cohort, time-to-next-treatment (TTNT) was further analysed; the presence of renal failure, splenomegaly and lung abnormalities were associated with worse TTNT. Our nationwide study not only demonstrated clinical characteristics and the outcome of patients with iHES but also for the first time revealed clinical factors associated with steroid dependency and duration of first-line corticosteroid efficacy.

World Health Organization and International Consensus Classification of eosinophilic disorders: 2024 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

The eosinophilias encompass a broad range of non-hematologic (secondary or reactive) and hematologic (primary or clonal) disorders with the potential for end-organ damage.

DIAGNOSIS

Hypereosinophilia (HE) has generally been defined as a peripheral blood eosinophil count greater than 1.5 × 109/L, and may be associated with tissue damage. After the exclusion of secondary causes of eosinophilia, diagnostic evaluation of primary eosinophilias relies on a combination of various tests. They include morphologic review of the blood and marrow, standard cytogenetics, fluorescence in situ hybridization, molecular testing and flow immunophenotyping to detect histopathologic or clonal evidence for an acute or chronic hematolymphoid neoplasm.

RISK STRATIFICATION

Disease prognosis relies on identifying the subtype of eosinophilia. After evaluation of secondary causes of eosinophilia, the 2022 World Health Organization and International Consensus Classification endorse a semi-molecular classification scheme of disease subtypes. This includes the major category "myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions" (MLN-eo-TK), and the MPN subtype, "chronic eosinophilic leukemia" (CEL). Lymphocyte-variant HE is an aberrant T-cell clone-driven reactive eosinophila, and idiopathic hypereosinophilic syndrome (HES) is a diagnosis of exclusion.

RISK-ADAPTED THERAPY

The goal of therapy is to mitigate eosinophil-mediated organ damage. For patients with milder forms of eosinophilia (e.g., <1.5 × 109/L) without symptoms or signs of organ involvement, a watch and wait approach with close follow-up may be undertaken. Identification of rearranged PDGFRA or PDGFRB is critical because of the exquisite responsiveness of these diseases to imatinib. Pemigatinib was recently approved for patients with relapsed or refractory FGFR1-rearranged neoplasms. Corticosteroids are first-line therapy for patients with lymphocyte-variant HE and HES. Hydroxyurea and interferon-α have demonstrated efficacy as initial treatment and in steroid-refractory cases of HES. Mepolizumab, an interleukin-5 (IL-5) antagonist monoclonal antibody, is approved by the U.S Food and Drug Administration for patients with idiopathic HES. Cytotoxic chemotherapy agents, and hematopoietic stem cell transplantation have been used for aggressive forms of HES and CEL, with outcomes reported for limited numbers of patients. Targeted therapies such as the IL-5 receptor antibody benralizumab, IL-5 monoclonal antibody depemokimab, and various tyrosine kinase inhibitors for MLN-eo-TK, are under active investigation.

Hypereosinophilic syndrome: a rare cause of ST-elevation myocardial infarction and thrombus formation on the aortic valve

We present a case of a man in his 30s presenting with ST-segment elevation myocardial infarction and eosinophilia. The patient underwent thrombus aspiration and initially echocardiographic evaluation was normal. The patient was discharged after 2 days, but was hospitalised again after 6 days. Echocardiographic evaluation now revealed a thrombus formation on the aortic valve. Laboratory data revealed increasing eosinophilia, and treatment with high-dosage corticosteroids and hydroxyurea was initiated as eosinophilic disease with organ manifestations could not be precluded. Eosinophils normalised and the patient was discharged again. The combination of hypereosinophilia and absence of infection, rheumatological disorders and malignancy, led to reactive or idiopathic hypereosinophilic syndrome being the most plausible diagnoses. The patient was closely monitored in the cardiology and haematology outpatient clinics. Echocardiographic evaluation, performed 6 weeks after the patient was discharged, showed significant regression in the size of the thrombus mass.

Gene Therapy for Immunoglobulin E, Complement-Mediated, and Eosinophilic Disorders

Immunoglobulin E, complement, and eosinophils play an important role in host defense, but dysfunction of each of these components can lead to a variety of human disorders. In this review, we summarize how investigators have adapted gene therapy and antisense technology to modulate immunoglobulin E, complement, and/or eosinophil levels to treat these disorders.

HES and EGPA: Two Sides of the Same Coin

Elevated eosinophil counts are implicated in multiple diseases, from relatively prevalent organ-specific disorders such as severe eosinophilic asthma, to rare multisystem disorders such as hypereosinophilic syndrome (HES) and eosinophilic granulomatosis with polyangiitis (EGPA). Patients with these multisystem diseases, often associated with markedly elevated eosinophil counts, have a substantial risk of morbidity and mortality due to delayed diagnosis or inadequate treatment. A thorough workup of symptomatic patients presenting with elevated eosinophil counts is essential, although in some cases the differential diagnosis may remain difficult because of overlapping presentations between HES and EGPA. Notably, first- and second-line treatment options and response to therapy may differ for specific HES and EGPA variants. Oral corticosteroids are the first line of treatment for HES and EGPA, except when HES is the result of specific mutations driving clonal eosinophilia that are amenable to targeted treatment with a kinase inhibitor. Cytotoxic or immunomodulatory agents may be required for those with severe disease. Novel eosinophil-depleting therapies, such as those targeting interleukin 5 or its receptor, have shown great promise in reducing blood eosinophil counts, and reducing disease flares and relapses in patients with HES and EGPA. Such therapies could reduce the side effects associated with long-term oral corticosteroids or immunosuppressant use. This review provides a pragmatic guide to approaching the diagnosis and clinical management of patients with systemic hypereosinophilic disorders. We highlight practical considerations for clinicians and present cases from real-world clinical practice to show the complexity and challenges associated with diagnosing and treating patients with HES and EGPA.

French guidelines for the etiological workup of eosinophilia and the management of hypereosinophilic syndromes

Eosinophilic-related clinical manifestations are protean and the underlying conditions underpinning eosinophilia are highly diverse. The etiological workup of unexplained eosinophilia/hypereosinophilia can be challenging, and can lead sometimes to extensive, inappropriate, costly and/or invasive investigations. To date, guidelines for the etiological workup and management of eosinophilia are mainly issued by hematologists, and thus mostly cover the scope of clonal hypereosinophilic syndromes (HES). Here, thanks to an extensive literature review, and thanks to the joint work of a large panel of experts involving physicians from both adult and pediatric medicine and from various subspecialties (as well as a representative of a patients' association representative), we provide recommendations for both the step-by step diagnostic workup of eosinophilia (whether unexplained or within specific contexts) as well as the management and follow-up of the full spectrum of eosinophilic disorders (including clonal, reactive, lymphocytic and idiopathic HES, as well as single-organ diseases). Didactic prescription summaries intended to facilitate the prescription of eosinophil-targeted drugs are also provided, as are practical diagnostic and therapeutic algorithms. Lastly, this set of recommendations also includes a summary intended for general practitioners, as well as an overview of the therapeutic patient education program set up by the French reference center for HES. Further updates will be mandatory as new validated information emerges.

Hypereosinophilic syndrome presenting with gastrointestinal manifestations

Hypereosinophilic syndrome (HES) is a spectrum of diseases characterised by an elevated eosinophilic count causing end-organ damage. Differential diagnoses of hypereosinophilia are vast and include drug hypersensitivities, allergies, infections, cancers, autoimmune disorders and rare eosinophilic syndromes. Herein, we describe a case of a patient presenting with gastrointestinal (GI) symptoms including progressive dysphagia, abdominal distension, vomiting, diarrhoea and abdominal pain with significant peripheral eosinophilia who was found to have an overlap HES involving the GI tract. This patient's eosinophilia was rapidly corrected with intravenous methylprednisolone, and the patient experienced gradual resolution of clinical symptoms with maintenance oral prednisone. Due to the rarity and diverse presentation of HES, there are few large, longitudinal studies that describe disease progression and inform treatment guidelines. This case demonstrates the difficulty in designing a treatment regimen for these patients and emphasises the clinical need for improved understanding of HES.

Multiple brain infarctions and endomyocarditis in ANCA-negative eosinophilic granulomatosis with polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA) is a small vessel necrotizing vasculitis characterized by asthma and eosinophilia. Ischemic stroke is a rare complication of the disease. We herein report a case involving a 77-year-old woman with sinusitis who developed embolic stroke and splenic infarctions. Laboratory tests revealed hypereosinophilia and elevated troponin-T and N-terminal pro-brain natriuretic peptide. Antineutrophil cytoplasmic antibodies (ANCA) studies were negative. Skin biopsy showed infiltration of eosinophils into the arterial walls. These clinicopathological findings led to the diagnosis of EGPA. We also found the evidence of endomyocarditis as revealed by multimodality cardiac imaging. The patient underwent continuous immunosuppressive and anticoagulation therapy, and the infarctions did not recur. This report highlights the importance of histologically proven vasculitis with eosinophil infiltration and careful examination for cardiac involvement, especially in ANCA-negative patients.

Systemic thrombo-embolic events in a middle-aged male with Loeffler endocarditis without peripheral eosinophilia-a case report

BACKGROUND

Loeffler-endocarditis (LE) is considered a chronic restrictive cardiomyopathy and manifestation of eosinophilic myocarditis characterized by eosinophilic infiltration. LE is a rare underdiagnosed disease and associated with high morbidity and mortality.

CASE PRESENTATION

We report a case of a 46-year-old man suffering from LE associated with thromboembolic events without peripheral eosinophilia. The patient presented with typical clinical signs of acute onset of limb ischaemia, predominantly on the right limb, indicating immediate iliacal thrombectomy and due to a severe compartment syndrome additional fasciotomy. Total occlusion also of left popliteal artery suggesting an impaired chronic and aggravated impaired perfusion indicated also urgent left sided revascularization. Subsequent echocardiography revealed severe left ventricular dysfunction with a striking amount of spontaneous echo-contrast, noticeable in the left ventricular cavity. Furthermore the initial CT scan demonstrated asymptomatic left kidney- and brain infarctions. Diagnostic workup including endomyocardial biopsy (EMB) of the left ventricle, uncovered an underlying LE without peripheral eosinophilia.

CONCLUSIONS

This case demonstrates and highlights the findings, treatment and outcome of a patient with LE and associated thrombo-embolic events without peripheral eosinophilia and emphazises the importance of awareness for LE in patients presenting with an acute cardiac decompensation and thrombo-embolic events. EMB should be performed early in unstable patients unsuitable for cardiovascular magnetic resonance imaging.

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.

World Health Organization-defined eosinophilic disorders: 2022 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

The eosinophilias encompass a broad range of nonhematologic (secondary or reactive) and hematologic (primary or clonal) disorders with potential for end-organ damage.

DIAGNOSIS

Hypereosinophilia (HE) has generally been defined as a peripheral blood eosinophil count greater than 1.5 × 10⁹ /L. After exclusion of secondary causes of eosinophilia, diagnostic evaluation of primary eosinophilias relies on morphologic review of the blood and marrow, standard cytogenetics, fluorescence in situ hybridization, next generation sequencing gene assays, and flow immunophenotyping to detect histopathologic or clonal evidence for an acute or chronic hematolymphoid neoplasm.

RISK STRATIFICATION

Disease prognosis relies on identifying the subtype of eosinophilia. After evaluation of secondary causes of eosinophilia, the 2016 World Health Organization endorses a semi-molecular classification scheme of disease subtypes. This includes the major category "myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRA, PDGFRB, or FGFR1 or with PCM1-JAK2", and the myeloproliferative neoplasm subtype, "chronic eosinophilic leukemia, not otherwise specified" (CEL, NOS). Lymphocyte-variant HE is an aberrant T-cell clone-driven reactive eosinophila, and idiopathic hypereosinophilic syndrome (HES) is a diagnosis of exclusion.

RISK-ADAPTED THERAPY

The goal of therapy is to mitigate eosinophil-mediated organ damage. For patients with milder forms of eosinophilia (eg, < 1.5 × 10⁹ /L) without symptoms or signs of organ involvement, a watch and wait approach with close follow-up may be undertaken. Identification of rearranged PDGFRA or PDGFRB is critical because of the exquisite responsiveness of these diseases to imatinib. Corticosteroids are first-line therapy for patients with lymphocyte-variant HE and HES. Hydroxyurea and interferon-α have demonstrated efficacy as initial treatment and in steroid-refractory cases of HES. Mepolizumab, an interleukin-5 (IL-5) antagonist monoclonal antibody, was recently approved by the US Food and Drug Administration for patients with idiopathic HES. The use of the IL-5 receptor antibody benralizumab, as well as other targeted therapies such as JAK2 and FGFR1 inhibitors, is under active investigation.

Loeffler endocarditis with intracardiac thrombus: case report and literature review

Background

Loeffler endocarditis is a relatively rare and potentially life-threatening heart disease. This study aimed to identify the characteristic features of Loeffler endocarditis with intracardiac thrombus on a background of hypereosinophilic syndrome (HES).

Case presentation

We described a 57-year-old woman with Loeffler endocarditis and intracardiac thrombus initially presenting with neurological symptoms, who had an embolic stroke in the setting of HES. After cardiac magnetic resonance (CMR), corticosteroids and warfarin were administered to control eosinophilia and thrombi, respectively. During a 10-month follow-up, the patient performed relatively well, with no adverse events. We also systematically searched PubMed and Embase for cases of Loeffler endocarditis with intracardiac thrombus published until July 2021. A total of 32 studies were eligible and included in our analysis. Further, 36.4% of recruited patients developed thromboembolic complications, and the mortality rate was relatively high (27.3%). CMR was a powerful noninvasive modality in providing diagnostic and follow-up information in these patients. Steroids were administered in 81.8% of patients, achieving a rapid decrease in the eosinophil count. Also, 69.7% of patients were treated with anticoagulant therapy, and the thrombus was completely resolved in 42.4% of patients. Heart failure and patients not treated with anticoagulation were associated with poor outcomes.

Conclusions

Cardiac involvement in HES, especially Loeffler endocarditis with intracardiac thrombus, carries a pessimistic prognosis and significant mortality. Early steroids and anticoagulation therapy may be beneficial once a working diagnosis is established. Further studies are needed to provide evidence-based evidence for managing this uncommon manifestation of HES.

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.

Normalization of left ventricular filling pressure after cardiac surgery for the Loeffler's endocarditis: a case report

Background

Loeffler endocarditis is a rare restrictive cardiomyopathy, characterized by hypereosinophilia and fibrous thickening of the endocardium causing progressive onset of heart failure and appearance of thrombi on the walls of the heart chambers.

Case summary

A 72-year-old man known for hypertension and dyslipidaemia consults for progressive dyspnoea up to New York Heart Association (NYHA) Classes 2–3 over 3 weeks. The biological balance sheet shows a high eosinophil level and an echocardiography shows a mild echodensity fixed to the left apex. After exclusion of a secondary cause of hypereosinophilia, diagnosis of endomyocardial fibrosis in the context of a hypereosinophilic syndrome (HES) is therefore retained. The patient’s clinical presentation with cardiac involvement leads us to start a treatment with corticosteroids. The patient is then regularly followed every 6 months with an initially stable course without complications. Two years later, he develops progressive signs of heart failure. Transthoracic echocardiography shows a left ventricular (LV) dilatation with a normal ejection fraction, but decreased volume due to a large echodense mass in the apex, and moderate aortic regurgitation caused by myocardial infiltration. In view of this rapid evolution, resection of the LV mass with concomitant aortic valve replacement is performed. Pathology confirms eosinophilic infiltration. The clinical course is very good with a patient who remains stable with dyspnoea NYHA Classes 1–2, and echocardiography at 1 year shows a normalization of LV filling pressure.

Discussion

HES represents a heterogeneous group of disorders characterized by overproduction of eosinophils. One of the major causes of mortality is associated cardiac involvement. Endocardial fibrosis and mural thrombosis are frequent cardiac findings. Echocardiography plays a crucial role in initial diagnosis of endomyocardial fibrosis, and for regular follow-up in order to adapt medical treatment and monitor haemodynamic evolution of the restrictive physiology and of valvular damage caused by the disease’s evolution. This case also shows that surgery can normalize filling pressure and allow a clear improvement on the clinical condition even at the terminal fibrotic state.

Hypereosinophilic syndrome: considerations for the cardiologist

Eosinophil-mediated endomyocardial damage is a well-known complication in patients with hypereosinophilic syndromes (HES). Although management and survival have improved significantly, some patients continue to develop severe cardiomyopathy as a direct consequence of uncontrolled hypereosinophilia. Cardiologists play a key role in early detection and treatment. At the early generally asymptomatic stage, related to subendocardial eosinophilic infiltrates, elevation of the biomarker of cardiac damage (serum troponin) and cardiac MRI are the best tools for diagnosis. As disease progresses, patients typically develop intracardiac mural thrombi and may experience variable degrees of heart failure due to valve damage and/or subendocardial fibrosis, all of which are more readily detectable with traditional echocardiographic investigation. New imaging modalities such as strain imaging and specific sequences in MRI offer the perspective of detecting subtle perturbations and distinguishing inflammatory versus fibrotic stages. Endomyocardial biopsy may help in difficult settings, namely, when blood eosinophilia is not prominent, but may be non-contributive due to sampling issues or eosinophil degranulation or replacement by fibrosis, and must always be performed after careful consideration of the risk:benefit ratio. Although treatment of the HES itself should be managed by clinicians with expertise in this rare disorder with the aim of lowering eosinophil counts to prevent and treat eosinophil-mediated organ damage and dysfunction, cardiologists play a key role in managing the associated cardiopathy. There are no consensual disease-specific guidelines for treating eosinophil-mediated thrombotic complications and cardiopathy, which should be managed according to classical international recommendations.

Bullous pemphigoid-like rash revealing hypereosinophilic syndrome

Hypereosinophilic syndrome (HES) is a rare haematologic disorder characterised by unexplained, persistent eosinophilia with organ involvement. We report the case of a 74-year-old patient who presented with a pemphigoid-like bullous rash as the only manifestation of an HES. This report highlights the importance of the dermatological manifestations of this potentially life-threating condition that may initially present as a skin-limited disease. Bullous pemphigoid (BP) is a very common autoimmune blistering dermatosis that may share common clinical and histological features or associate with an HES. HES should be considered when patients diagnosed with BP demonstrate atypical course under corticosteroids and/or recalcitrant blood eosinophilia.

Idiopathic hypereosinophilic syndrome with intracardiac atypical linear-shaped and floating thrombus presenting as embolic cerebral infarction

Knowledge of the multi-organ involvement in hypereosinophilic syndrome (HES) is important for the diagnosis and care of patients with this condition, even in cases with atypical presentation. This report aims to describe cerebral embolic infarction and intracardiac atypical linear-shaped thrombus in a patient with idiopathic HES and to discuss the approach of appropriate diagnosis and timely interventional management. A 55-year-old man presented with general weakness, including left-sided weakness, mild cognitive dysfunction, and mild exertional dyspnea for about 2 weeks. Initial magnetic resonance imaging for evaluating the brain showed multifocal acute to subacute infarction of both cerebral hemispheres and both cerebellums. Laboratory findings revealed leukocytosis (25,620 cells/mm³) and eosinophilia (54.9%). To evaluate the intracardiac embolic source, the patient underwent echocardiography, and a 1.5 cm linear thread-like and mobile mass was detected. Consequently, the patient was diagnosed with idiopathic HES. After bone marrow biopsy, corticosteroid and hydroxyurea were administered to control the eosinophilia. This case indicates that HES can present as a floating intracardiac atypical linear-shaped thrombus attached to the left ventricle. After appropriate diagnostic approaches, proper treatment could be given for the patient. <Learning objective: Idiopathic hypereosinophilic syndrome (HES) is a disorder characterized by persistent eosinophilia with heterogeneous clinical manifestations. Knowledge of the multi-organ involvement in HES is important for the diagnosis and care of patients with this condition, even in cases with atypical shaped thrombus as clinical presentation. Close monitoring combined with early treatment and diagnosis may help reduce mortality in HES patients.>.

Idiopathic hypereosinophilic syndrome: A rare diagnosis in children

Idiopathic hypereosinophilic syndrome (IHES) is one of numerous hypereosinophilic syndromes. The incidence of IHES among children is unknown, but it is considered a rare disease. We report a pediatric case of IHES and the challenges to finding an effective treatment. The patient described here was responsive to prednisolone and thalidomide.

Gastrointestinal Manifestations of Hypereosinophilic Syndromes and Mast Cell Disorders: a Comprehensive Review

Hypereosinophilic syndrome and mastocytosis are relatively rare proliferative diseases encountered in the general population. However, allergists frequently consider these disorders in the differential of patients presenting with gastrointestinal, pulmonary, cutaneous, and allergic symptoms. Gastrointestinal symptoms are some of the most frequent and/or debilitating aspects of both disease states and in many cases lead to poor quality of life and functional limitation for the patient. They are the third most common clinical manifestation in hypereosinophilic syndrome and have been found to be the most distressful aspect of the disorder in those with systemic mastocytosis. Both eosinophils and mast cells play integral parts in normal gut physiology, but when and how exactly their effector functionality translates into clinically significant disease remains unclear, and the available literature regarding their pathophysiology remains sparse. Eosinophils and mast cells even, in fact, may not necessarily function in isolation from each other but can participate in bidirectional crosstalk. Both are affected by similar mediators and can also influence one another in a paracrine fashion. Their interactions include both production of soluble mediators for specific eosinophil and mast cell receptors (for example, eosinophil recruitment and activation by mast cells releasing histamine and eotaxin) as well as direct physical contact. The mechanistic relationship between clonal forms of hypereosinophilia and systemic mastocytosis has also been explored. The nature of gastrointestinal symptomatology in the setting of both hypereosinophilic syndrome and mast cell disease is frequently manifold, heterogeneous, and the lack of better targeted therapy makes diagnosis and management challenging, especially when faced with a substantial differential. Currently, the management of these gastrointestinal symptoms relies on the treatment of the overall disease process. In hypereosinophilia patients, systemic corticosteroids are mainstay, although steroid-sparing agents such as hydroxyurea, IFN-α, methotrexate, cyclosporine, imatinib, and mepolizumab have been utilized with varying success. In mastocytosis patients, anti-mediator therapy with antihistamines and mast cell stabilization with cromolyn sodium can be considered treatments of choice, followed by other therapies yet to be thoroughly studied, including the role of the low-histamine diet, corticosteroids, and treatment of associated IBS symptoms. Given that both eosinophils and mast cells may have joint pathophysiologic roles, they have the potential to be a combined target for therapeutic intervention in disease states exhibiting eosinophil or mast cell involvement.

Acute kidney injury secondary to thrombotic microangiopathy associated with idiopathic hypereosinophilic syndrome: a case report and review of the literature

Background

Renal involvement in idiopathic hypereosinophilic syndrome is uncommon. The mechanism of kidney damage can be explained as occurring via two distinct pathways: (1) thromboembolic ischemic changes secondary to endocardial disruption mediated by eosinophilic cytotoxicity to the myocardium and (2) direct eosinophilic cytotoxic effect to the kidney.

Case presentation

We present a case of a 63-year-old Caucasian man who presented to our hospital with 2 weeks of progressively generalized weakness. He was diagnosed with idiopathic hypereosinophilic syndrome with multiorgan involvement and acute kidney injury with biopsy-proven thrombotic microangiopathy. Full remission was achieved after 8 weeks of corticosteroid therapy.

Conclusion

Further studies are needed to investigate if age and absence of frank thrombocytopenia can serve as a prognostic feature of idiopathic hypereosinophilic syndrome, as seen in this case.

World Health Organization-defined eosinophilic disorders: 2019 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

The eosinophilias encompass a broad range of non-hematologic (secondary or reactive) and hematologic (primary, clonal) disorders with potential for end-organ damage.

DIAGNOSIS

Hypereosinophilia has generally been defined as a peripheral blood eosinophil count greater than 1.5 × 10⁹ /L, and may be associated with tissue damage. After exclusion of secondary causes of eosinophilia, diagnostic evaluation of primary eosinophilias relies on a combination of various tests. They include morphologic review of the blood and marrow, standard cytogenetics, fluorescence in situ-hybridization, flow immunophenotyping, and T-cell clonality assessment to detect histopathologic or clonal evidence for an acute or chronic hematolymphoid neoplasm.

RISK STRATIFICATION

Disease prognosis relies on identifying the subtype of eosinophilia. After evaluation of secondary causes of eosinophilia, the 2016 World Health Organization endorses a semi-molecular classification scheme of disease subtypes. This includes the major category "myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRA, PDGFRB, or FGFR1 or with PCM1-JAK2", and the MPN subtype, "chronic eosinophilic leukemia, not otherwise specified" (CEL, NOS). Lymphocyte-variant hypereosinophilia is an aberrant T-cell clone-driven reactive eosinophila, and idiopathic hypereosinophilic syndrome (HES) is a diagnosis of exclusion.

RISK-ADAPTED THERAPY

The goal of therapy is to mitigate eosinophil-mediated organ damage. For patients with milder forms of eosinophilia (eg, <1.5 × 10⁹ /L) without symptoms or signs of organ involvement, a watch and wait approach with close-follow-up may be undertaken. Identification of rearranged PDGFRA or PDGFRB is critical because of the exquisite responsiveness of these diseases to imatinib. Corticosteroids are first-line therapy for patients with lymphocyte-variant hypereosinophilia and HES. Hydroxyurea and interferon-alfa have demonstrated efficacy as initial treatment and in steroid-refractory cases of HES. In addition to hydroxyurea, second line cytotoxic chemotherapy agents, and hematopoietic stem cell transplantation have been used for aggressive forms of HES and CEL, with outcomes reported for limited numbers of patients. The use of antibodies against interleukin-5 (IL-5) (mepolizumab), the IL-5 receptor (benralizumab), as well as other targets on eosinophils remains an active area of investigation.

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

Eosinophilic disorders represent a group of pathologic conditions with highly heterogeneous pathophysiology and clinical presentation and variable prognosis, ranging from asymptomatic or mild, to severe and complex cases, with fatal outcome. Interest in this group of disorders has increased during the last two decades, with consistent progress made regarding understanding of molecular mechanisms, refining of diagnostic criteria, classification and evaluation of therapeutic options. There are still many gaps and difficulties in evaluating eosinophilic syndromes and diseases in medical practice. The disease prognosis depends mainly on the cause and mechanism of eosinophilia, on severity of organ dysfunction and on accurate diagnosis and response to treatment. Besides primary hypereosinophilic syndromes and secondary (reactive) eosinophilias, many associated or idiopathic forms have been described, making this topic a complex and difficult medical entity. An important aim of the experts in the field is to agree upon a more clear and practically useful classification, a better characterization of various phenotypes and endotypes of eosinophilic diseases and to identify novel biomarkers and more effective therapies. The aim of this paper is to review recent data from the literature regarding definition, classification and diagnosis criteria of eosinophilic diseases and to propose a revised and updated diagnostic algorithm useful in clinical practice.

Thrombosis in the portal venous system caused by hypereosinophilic syndrome: A case report

RATIONALE

Extensive thrombosis in the portal venous system caused by hypereosinophilic syndrome (HES) is rare, and there is no consensus on anticoagulant and thrombolytic treatments for arteriovenous thrombosis caused by HES.

PATIENT CONCERNS

The clinical data of a patient with extensive thrombosis in his portal venous system (superior mesenteric, splenic, hepatic, and portal veins), renal artery thrombosis, and mesenteric thrombosis caused by HES with secondary gastrointestinal bleeding and intestinal necrosis were retrospectively analyzed. Before admission, his eosinophil count increased to 7.47 × 10/L, and HES had been confirmed via bone marrow cytology. The patient experienced fever, cough, abdominal pain, massive hematemesis, and hematochezia that developed in succession. Abdominal computed tomography showed portal vein and superior mesenteric vein thromboses.

DIAGNOSIS

Hypereosinophilic syndrome; extensive thrombosis in the portal venous system; acute eosinophil-associated pneumonia; gastrointestinal bleeding; intestinal necrosis.

INTERVENTIONS

The patient was first treated with methylprednisolone, plasma exchange/hemofiltration, and single or combined use of unfractionated heparin and argatroban for anticoagulation. He was also administered alteplase and urokinase, successively, for thrombolytic treatment. Once the thromboses finally disappeared, the patient underwent surgery to excise a necrotic intestinal canal.

OUTCOMES

The thromboses disappeared with these treatments, and the patient recovered after the necrotic intestinal canal was excised.

LESSONS

The clinical manifestations of HES are complex and varied, and this condition can cause severe and extensive arteriovenous thrombosis. Anticoagulation therapy and thrombolysis are necessary interventions, and appear to be safe and effective.

Imatinib for the treatment of hypereosinophilic syndromes

INTRODUCTION

Hypereosinophilic syndromes (HES) encompass a group of disorders defined by sustained peripheral blood hypereosinophilia >1500/mm³ and evidence of eosinophilia-associated organ impairment. Approximately 10% of HES patients may harbor a cryptic deletion on chromosome 4 leading to formation of the FIP1L1-PDGFRA (F/P) fusion gene; these patients are diagnosed as F/P-mutated myeloid/lymphoid neoplasms with eosinophilia (MLN-eo). Areas covered: This review discusses the results of IM treatment in HES depending on mutation status. The literature on IM therapy in HES by searching PubMed for the terms 'imatinib mesylate', 'hypereosinophilic syndromes' and 'FIP1L1-PDGFRA' has been reviewed. The author's publications as well as his own experience in the field of HES treatment remain a significant contribution to this work. Expert commentary: Imatinib mesylate, a first generation tyrosine kinase inhibitor, has revolutionized the therapeutic approach to patients with hypereosinophilic syndromes and detectable F/P fusion gene. The response to IM in F/P-mutated MLN-eo is universal with minimal side effects. IM at 100mg per day induces complete molecular remission and even lower doses can be efficient to maintain durable response. Some patients may remain in continued remission after IM discontinuation. Resistance to IM is associated with dismal prognosis. IM is less effective in F/P-unmutated HES with short-lived response.

Eosinophil Development, Disease Involvement, and Therapeutic Suppression

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

World Health Organization-defined eosinophilic disorders: 2017 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

The eosinophilias encompass a broad range of nonhematologic (secondary or reactive) and hematologic (primary, clonal) disorders with potential for end-organ damage.

DIAGNOSIS

Hypereosinophilia has generally been defined as a peripheral blood eosinophil count greater than 1500/mm³ and may be associated with tissue damage. After exclusion of secondary causes of eosinophilia, diagnostic evaluation of primary eosinophilias relies on a combination of morphologic review of the blood and marrow, standard cytogenetics, fluorescent in situ-hybridization, flow immunocytometry, and T-cell clonality assessment to detect histopathologic or clonal evidence for an acute or chronic myeloid or lymphoproliferative disorder.

RISK STRATIFICATION

Disease prognosis relies on identifying the subtype of eosinophilia. After evaluation of secondary causes of eosinophilia, the 2016 World Health Organization endorses a semi-molecular classification scheme of disease subtypes which includes the major category "myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRA, PDGFRB, or FGFR1 or with PCM1-JAK2," and the "MPN subtype, chronic eosinophilic leukemia, not otherwise specified" (CEL, NOS). Lymphocyte-variant hypereosinophilia is an aberrant T-cell clone-driven reactive eosinophila, and idiopathic hypereosinophilic syndrome (HES) is a diagnosis of exclusion.

RISK-ADAPTED THERAPY

The goal of therapy is to mitigate eosinophil-mediated organ damage. For patients with milder forms of eosinophilia (e.g., < 1500/mm³ ) without symptoms or signs of organ involvement, a watch and wait approach with close-follow-up may be undertaken. Identification of rearranged PDGFRA or PDGFRB is critical because of the exquisite responsiveness of these diseases to imatinib. Corticosteroids are first-line therapy for patients with lymphocyte-variant hypereosinophilia and HES. Hydroxyurea and interferon-alpha have demonstrated efficacy as initial treatment and steroid-refractory cases of HES. In addition to hydroxyurea, second line cytotoxic chemotherapy agents and hematopoietic cell transplant have been used for aggressive forms of HES and CEL with outcomes reported for limited numbers of patients. The use of antibodies against interleukin-5 (IL-5) (mepolizumab), the IL-5 receptor (benralizumab), and CD52 (alemtuzumab), as well as other targets on eosinophils remains an active area of investigation.

[Clinical characteristics and long- term therapeutic effects of 60 patients with idiopathic hypereosinophilic syndrome in a single center]

Objective: To analyze the long term outcome of patients with hypereosinophilic syndrome(HES). Methods: The clinical characteristics and efficacy of 60 newly diagnosed HES patients who received corticosteroids(CS)monotherapy were retrospectively analyzed. The survival and death causes of patients were obtained by follow- up. Results: Of all 60 HES patients, 45 were male and 15 female. The median age was 38(11-80)years old. The most frequent organ involvement of HES occurred in cutaneous(55.0%), gastrointestinal(40.0%), pulmonary(35.0%), cardiac(13.3%), vascular(10.0%)and neuromuscular system(10.0%). Single organ involvement was observed in 45.0% of the patients, two or at least three organ involvements were observed in 36.7% and 18.3%, respectively. The median daily dose of prednisone equivalent was 30(15-60)mg. The total response rate(CR plus PR)was 88.3%, and the rate was elevated to 93.3% after receiving alterative or combined treatment regimens. Thirty- eight patients with response to treatment received corticosteroid(CS)as mono(33 cases)or combined(5 cases)maintenance treatment with a median duration of 51(5-92)months; the median maintenance daily dose of prednisone equivalent was 5(1.25-40)mg. Twenty patients experienced cessation of CS. The main causes of patients' withdrawal were poor compliance after CR or ineffective treatment. The 5-year overall survival was(90.0±4.3)%, and the main cause of mortality was cardiac dysfunction. Conclusion: CS was highly effective on HES with manageable side effects. Most patients who have not obtained satisfactory effect could improve response via combination therapy. Cardiac dysfunction was the most common cause of mortality.

Chronic Eosinophilic Leukemia Presenting Predominantly with Cutaneous Manifestations

A 37-year-old male presented with severe oral and genital mucosal ulcers, lichenoid eruption and twenty-nail dystrophy. Systemic examination was normal, except for anemia. On investigations, he was found to have persistently elevated peripheral eosinophilia, absolute eosinophil count >5000/mm³, bone marrow showing increased eosinophilic precursors, and infiltration by atypical cells. The serum vitamin B12 levels were grossly elevated, and Philadelphia chromosome study was negative. Thus, a diagnosis of chronic eosinophilic leukemia was made. The patient showed excellent response to imatinib mesylate. We are reporting a rare type of leukemia presenting with predominantly cutaneous manifestations.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Biventricular thrombus in hypereosinophilic syndrome presenting with shortness of breath

A 48 years old male presented to clinic with 12 months of low grade fever with shortness of breath which has progressively worsened with no associated weight loss, night sweats or loss of appetite. There was no prior history of chronic illness before the current illness. Laboratory workup revealed a high white blood cell count with predominant eosinophils. Chest X-ray was normal. Transthoracic echocardiography and Cardiac Magnetic Resonance showed biventricular thrombi. On further extensive workup the findings were consistent with hypereosinophilic syndrome. The patient was started on oral steroids, hydroxyurea, imatanib mesylate and oral anticoagulation. The patient responded to the treatment with complete resolution of his symptoms over the course of few months. The repeat Echocardiogram after a year showed normal left ventricular systolic and diastolic function with complete resolution of biventricular thrombi.

World Health Organization-defined eosinophilic disorders: 2015 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

The eosinophilias encompass a broad range of non-hematologic (secondary or reactive) and hematologic (primary, clonal) disorders with potential for end-organ damage.

DIAGNOSIS

Hypereosinophilia has generally been defined as a peripheral blood eosinophil count greater than 1,500/mm(3) and may be associated with tissue damage. After exclusion of secondary causes of eosinophilia, diagnostic evaluation of primary eosinophilias relies on a combination of morphologic review of the blood and marrow, standard cytogenetics, fluorescent in situ-hybridization, flow immunocytometry, and T-cell clonality assessment to detect histopathologic or clonal evidence for an acute or chronic myeloid or lymphoproliferative disorder.

RISK STRATIFICATION

Disease prognosis relies on identifying the subtype of eosinophilia. After evaluation of secondary causes of eosinophilia, the 2008 World Health Organization establishes a semi-molecular classification scheme of disease subtypes including 'myeloid and lymphoid neoplasms with eosinophilia and abnormalities of PDGFRA, PDGFRB, or FGFR1', chronic eosinophilic leukemia, not otherwise specified, (CEL, NOS), lymphocyte-variant hypereosinophilia, and idiopathic hypereosinophilic syndrome (HES), which is a diagnosis of exclusion.

RISK-ADAPTED THERAPY

The goal of the therapy is to mitigate eosinophil-mediated organ damage. For patients with milder forms of eosinophilia (e.g. < 1,500/mm(3) ) without symptoms or signs of organ involvement, a watch and wait approach with close-follow-up may be undertaken. Identification of rearranged PDGFRA or PDGFRB is critical because of the exquisite responsiveness of these diseases to imatinib. Corticosteroids are first-line therapy for patients with lymphocyte-variant hypereosinophilia and HES. Hydroxyurea and interferon-alpha have demonstrated efficacy as initial treatment and steroid-refractory cases of HES. In addition to hydroxyurea, second line cytotoxic chemotherapy agents and hematopoietic cell transplant have been used for aggressive forms of HES and CEL with outcomes reported for limited numbers of patients. Although clinical trials have been performed with anti IL-5 (mepolizumab) and anti-CD52 (alemtuzumab) antibodies, their therapeutic role in primary eosinophilic diseases and HES has yet to be established.

Atypical Presentation of Intracardiac Floating Thrombi in Hypereosinophilic Syndrome Complicated With Stroke and Systemic Embolization: A Case Report

Hypereosinophilic syndrome (HES) describes a disorder characterized by persistent peripheral blood eosinophilia with evidence of multiple target organs damage caused by eosinophilia. HES most commonly involves the heart, and cardiac involvement typically presents in the form of endomyocarditis or myocarditis with apical mural thrombus formation.We present a case with atypical cardiac presentation with massive intracardiac fragile thrombi, causing peripheral emboli and strokes.HES can present as floating thrombi with thin attachment to the left ventricle, and clinicians should also be vigilant of thromboembolic complications and initiate early therapy to prevent or reduce the potential complications of HES.

A Rare Case of Aortic Valve Thrombosis in Patient with Idiopathic Hypereosinophilic Syndrome

Idiopathic hypereosinophilic syndrome (HES) is characterized by persistent eosinophilia and eosinophil-mediated organ-system damage. Cardiac thrombosis and thromboembolic complications represent common causes of morbidity and mortality and usually involve cardiac ventricles or mitral and prosthetic valves, while the involvement of the aortic valve is extremely rare in HES. Here we report peculiar multimodality images of an atypical case of extended thrombosis of the aortic valve, complicated by myocardial ischemia and asymptomatic cerebral ischemia, likely due to thrombus embolization, occurring in a 48-year-old man with HES. Prompt anticoagulant and steroid therapy lead to rapid and complete resolution of the thrombotic lesions, allowing preserving the native valve and preventing further embolic events.

Reversible Severe Eosinophilic Endomyocardial Fibrosis During Pregnancy: A Case Report

Idiopathic hypereosinophilic syndrome (HES) is a condition of unknown origin characterized by clinical manifestations attributable to eosinophilia and eosinophilic infiltration of tissues. Cardiac involvement is rare and threatening accounting for 33% to 43% of death in HES. Management of pregnant patients with HES is challenging and have rarely been reported, particularly in the setting of heart failure.We here report on the case of a 29-year-old woman with HES who developed severe endomyocardial fibrosis with heart failure during pregnancy. Outcome was favorable under treatment with prednisone and azathioprine.This case illustrates a favorable outcome of endomyocardial fibrosis during pregnancy.

CCR2 deficiency leads to increased eosinophils, alternative macrophage activation, and type 2 cytokine expression in adipose tissue

Adipose tissue (AT) inflammation during obesity is mediated by immune cells and closely correlates with systemic insulin resistance. In lean AT, eosinophils are present in low but significant numbers and capable of promoting alternative macrophage activation in an IL-4/IL-13-dependent manner. In WT mice, obesity causes the proportion of AT eosinophils to decline, concomitant with inflammation and classical activation of AT macrophages. In this study, we show that CCR2 deficiency leads to increased eosinophil accumulation in AT. Furthermore, in contrast to WT mice, the increase in eosinophils in CCR2(-/-) AT is sustained and even amplified during obesity. Interestingly, a significant portion of eosinophils is found in CLSs in AT of obese CCR2(-/-) mice, which is the first time eosinophils have been shown to localize to these inflammatory hot spots. CCR2(-/-) bone marrow precursors displayed increased expression of various key eosinophil genes during in vitro differentiation to eosinophils, suggesting a potentially altered eosinophil phenotype in the absence of CCR2. In addition, the proportion of eosinophils in AT positively correlated with local expression of Il5, a potent eosinophil stimulator. The increase in eosinophils in CCR2(-/-) mice was detected in all white fat pads analyzed and in the peritoneal cavity but not in bone marrow, blood, spleen, or liver. In AT of CCR2(-/-) mice, an increased eosinophil number positively correlated with M2-like macrophages, expression of the Treg marker Foxp3, and type 2 cytokines, Il4, Il5, and Il13. This is the first study to link CCR2 function with regulation of AT eosinophil accumulation.

Management of hypereosinophilia in tropical settings

Hypereosinophilia includes a group of commonly encountered clinical situations with symptoms ranging from mild and clinically innocuous to devastating presentations with high morbidity and mortality. The presentations and complications can be easily missed if the clinician is unaware of the diverse entities responsible for hypereosinophilia. The hypereosinophilic syndromes encompass entities that are associated with varying degrees of organ dysfunction either directly due to eosinophilic infiltration or as a result of substances secreted by the eosinophils. These conditions may be neoplastic or reactive in aetiology and a diligent search for secondary causes is essential. Evaluation and management algorithms in the tropical setting and in developing countries may differ from elsewhere. A review of hypereosinophilia and hypereosinophilic syndromes is presented with a diagnostic and therapeutic decision making algorithm modified for use in the tropical setting.

Recurrent severe acute hepatitis caused by hypereosinophilic syndrome associated with elevated serum immunoglobulin G4 levels

A 46-year-old male was admitted to our hospital with severe acute hepatitis, hypereosinophilia, and serum immunoglobulin G4 (IgG4) elevation. Plasma exchange was performed, and he was treated by prednisolone; however, his hepatitis recurred twice over the following twelve months. Transjuglar liver biopsy was performed at the third onset, which demonstrated extensive hepatocyte necrosis, congestion, and severe eosinophil infiltration. We diagnosed hypereosinophilic syndrome (HES)-related hepatitis. Although no cholangitis was detected by imaging and pathological diagnosis, IgG4-positive cells were detected in the liver and bone marrow. Furthermore, the elevation of serum IgG4 levels was associated with the eosinophil count and his clinical condition. After the addition of azathioprine to his treatment regimen, no reoccurrence was observed. IgG4-positive cells may have contributed to the severity and refractoriness of this recurrent acute HES-related hepatitis.

World Health Organization-defined eosinophilic disorders: 2014 update on diagnosis, risk stratification, and management

DISEASE OVERVIEW

The eosinophilias encompass a broad range of nonhematologic (secondary or reactive) and hematologic (primary, clonal) disorders with potential for end-organ damage.

DIAGNOSIS

Hypereosinophilia (HE) has generally been defined as a peripheral blood eosinophil count greater than 1,500/mm(3) and may be associated with tissue damage. After exclusion of secondary causes of eosinophilia, diagnostic evaluation of primary eosinophilias relies on a combination of morphologic review of the blood and marrow, standard cytogenetics, fluorescent in situ hybridization, flow immunocytometry, and T-cell clonality assessment to detect histopathologic or clonal evidence for an acute or chronic myeloid or lymphoproliferative disorder.

RISK STRATIFICATION

Disease prognosis relies on identifying the subtype of eosinophilia. After evaluation of secondary causes of eosinophilia, the 2008 World Health Organization establishes a semimolecular classification scheme of disease subtypes including "myeloid and lymphoid neoplasms with eosinophilia and abnormalities of PDGFRA, PDGFRB, or FGFR1', chronic eosinophilic leukemia, not otherwise specified" (CEL, NOS), lymphocyte-variant HE, and idiopathic hypereosinophilic syndrome (HES), which is a diagnosis of exclusion.

RISK-ADAPTED THERAPY

The goal of therapy is to mitigate eosinophil-mediated organ damage. For patients with milder forms of eosinophilia (e.g., <1,500/mm(3)) without symptoms or signs of organ involvement, a watch and wait approach with close-follow-up may be undertaken. Identification of rearranged PDGFRA or PDGFRB is critical because of the exquisite responsiveness of these diseases to imatinib. Corticosteroids are first-line therapy for patients with lymphocyte-variant HE and HES. Hydroxyurea and interferon-alpha have demonstrated efficacy as initial treatment and steroid-refractory cases of HES. In addition to hydroxyurea, second-line cytotoxic chemotherapy agents and hematopoietic cell transplant have been used for aggressive forms of HES and CEL with outcomes reported for limited number of patients. Although clinical trials have been performed with anti-IL-5 (mepolizumab) and anti-CD52 (alemtuzumab) antibodies, their therapeutic role in primary eosinophilic diseases and HES has yet to be established.