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

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.

Cardiac endothelial sarcoma with hypereosinophilia of children: a case report

Cardiac malignancies in children are extremely rare and they with hypereosinophilia are rather relatively uncommon. The majority of individuals may survive over the long term even with heart tumors provided they don't have any significant symptoms and their hemodynamics are unaffected. But we should nevertheless be aware of them, especially when they are coupled with persistent hypereosinophilia and the development of a hemodynamic anomaly. The case of a malignant heart tumor with hypereosinophilia in a 13-year-old girl is presented in this paper. She exhibited an echocardiographic deficit and a heart murmur. Additionally, it was difficult to treat her hypereosinophilia. Nevertheless, it was resolved the day after the operation. We presume that there is a certain relationship between them. This study gives clinicians a wide range of options for analyzing the connections between malignancy and hypereosinophilia.

Diagnostic spectrum of hypereosinophilia based on bone marrow pathology: 10 years' experience at a tertiary care hospital

BACKGROUND

Hypereosinophilia (HE) is defined as peripheral blood (PB) eosinophil count exceeding 1.5 × 10⁹ /L. As the causes of HE can be diverse, the work-up of patients was complicated. In this study, we aimed to categorize the underlying diseases associated with HE and demonstrate minimum diagnostic approach.

METHODS

Cases presenting with HE within 7 days of bone marrow (BM) examination conducted between 2008 and 2019 were selected. Cases were classified by the revised 2022 WHO and ICC classification. We also assessed morphologic features of unclassified persisting HE (>4 weeks) patients according to the morphologic criteria suggested a previous study by Wang et al. RESULTS: A total of 364 patients were included. The work-up confirmed primary HE in 38.7%, secondary HE in 48.9%, HE patients with insufficient evaluation in 13.7%. When conducted a slide review of HE patients with sustained HE more than 4 weeks among HE patients with insufficient evaluation, the morphological features showed abnormal eosinophils in PB/BM (69.0%/81.0%), hypercellularity (26.2%), myelofibrosis (7.1%), increased M:E ratio (5.3%), and dysmegakaryopoiesis (4.8%). Of these patients, 14 patients who met all morphologic criteria were suspected of CEL.

CONCLUSIONS

This study demonstrates that HE is associated with variable conditions. BM morphological assessment based on a robust criterion can help to confirm a MN irrespective of the presence of clonal markers. The work-up of patients in whom ruled out the common secondary causes of HE requires a systematic but sufficient approach including at a minimum BM karyotyping, PDGFRA testing, lymphocyte immunophenotyping and TCR gene rearrangement.

Gene therapy in a murine model of chronic eosinophilic leukemia-not otherwise specified (CEL-NOS)

Chronic eosinophilic leukemia-not otherwise specified (CEL-NOS) is a rare, aggressive, fatal disease characterized by blood eosinophilia and dysfunction of organs infiltrated with eosinophils. Clinically, the disease manifests with weight loss, cough, weakness, diarrhea, and multi-organ dysfunction that is unresponsive to therapy. We developed a one-time gene therapy for CEL-NOS using an adeno-associated virus (AAV) expressing an anti-eosinophil monoclonal antibody (AAVrh.10mAnti-Eos) to provide sustained suppression of eosinophil numbers in blood, thus reducing eosinophil tissue invasion and organ dysfunction. A novel CEL-NOS model was developed in NOD-scid IL2rγ^null (NSG) mice by administration of AAV expressing the cytokine IL5 (AAVrh.10mIL5), resulting in marked peripheral and tissue eosinophilia of the heart, lung, liver, and spleen, and eventually death. Mice were administered AAVrh.10mAnti-Eos (10¹¹ genome copies) 4 wk after administration of AAVrh.10mIL5 and evaluated for anti-eosinophil antibody expression, blood eosinophil counts, organ eosinophil invasion, and survival. AAVrh.10mAnti-Eos expressed persistent levels of the anti-eosinophil antibody for >24 wk. Strikingly, CEL-NOS treated mice had markedly lower blood eosinophil levels and reduced mortality when compared with control treated mice. These results suggest that a single treatment with AAVrh.10mAnti-Eos has the potential to provide substantial therapeutic benefit to patients with CEL-NOS, a fatal malignant disorder.

Potent Anti-Inflammatory Effects of Tetracyclines on Human Eosinophils

Eosinophils are potent pro-inflammatory cells. Not only in allergic diseases but also in other diseases there is a need for treatment strategies to induce resolution of eosinophil-mediated inflammation. During the last years beneficial non-antibiotic activities of tetracyclines (TCNs) have been shown in different diseases in which eosinophils play a role, for example, asthma and bullous pemphigoid. The working mechanism of these effects remains to be clarified. Aim of the present study was to investigate the effects of TCNs on eosinophils. Flow cytometry analysis of apoptosis, mitochondrial membrane potential, activation of caspases, intracellular H₂O₂ and calcium, surface expression of eosinophil activation markers was performed in highly purified peripheral blood eosinophils of non-atopic donors. Tetracycline hydrochloride, minocycline and doxycycline significantly induced eosinophil apoptosis. All TCNs were able to significantly overcome the strong survival enhancing effects of pro-eosinophilic cytokines and staphylococcus aureus enterotoxins. Tetracycline hydrochloride induced eosinophil apoptosis was accompanied by intracellular production of hydrogen peroxide, loss of mitochondrial membrane potential and activation of caspases. Moreover, tetracycline hydrochloride significantly down regulated eosinophil surface expression of CD9 and CD45, and of the activation markers CD11b and CD69, but not of CD54, CD63, or CD95. Our data, propably for the first time, point to a potent anti-inflammatory role of TCNs on eosinophils.

Intermediate between Idiopathic Hypereosinophilia and Chronic Eosinophilic Leukemia: A Report of Two Hypereosinophilic Cases with Possible Novel Molecular Mutations

To distinguish a reactive eosinophilia from its malignant counterpart is challenging. Establishing clonality of the eosinophils is crucial and considered the determining factor for establishing a diagnosis. Cases of hypereosinophilia without clear reactive etiologies, no evidence of end-organ damage, normal cytogenetics, and no molecular mutations are termed as “Idiopathic Hypereosinophilia (IHE).” For cases which lie between the spectrum of chronic eosinophilic leukemia (CEL) and IHE, identification of underlying molecular abnormalities might be helpful in better understanding the disease process and prognosis. Here, we report two cases of hypereosinophilia in which five possible novel molecular mutations were identified by targeted next-generation sequencing (NGS) analysis. They were FBXW7, KM2A, TCF3, ERBB4, and MET. With multiple genetic mutations, these cases could be classified as chronic eosinophilic leukemia. Both these young patients responded well to steroid therapy. While targeted NGS is a useful tool in identifying new molecular mutation associated with hypereosinophilia, our cases raise the question of further investigating this entity and if there is a possibility of an intermediate category lying between the spectrum of CEL and IHE. Defining hypereosinophilia with clonal molecular abnormality as a malignant process may need to be revisited. Even though attempts are being made to identify mutations in IHE, it might be more significant clinically to differentiate them based on response to steroid therapy and prognosis.

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.

Eosinophilic pancreatitis: a review of the pathophysiology, diagnosis, and treatment

Eosinophilic pancreatitis (EP) is an extremely rare disease caused by purely eosinophilic infiltration of the pancreas. EP is prone to being misdiagnosed as pancreatic cancer, causing unnecessary economic and physical harm to the patient. We report three cases of EP that were cured by steroids without relapse from 2017 to now. The clinical data of the three patients, including clinical manifestations, serological manifestations, imaging (ultrasound, computed tomography, and MRI), pathological diagnosis and treatment, and telephone follow-up of all patients, were retrospectively analysed. In addition, a literature search was conducted on the Web of Science and PubMed databases using key terms related to EP, considering case reports with no restrictions on the date of publication or language. In conclusion, we analysed 19 cases and determined the diagnostic criteria for EP. The diagnostic algorithm for EP can be used to diagnose EP easily. We hope that our standards and algorithm can reduce the rate of misdiagnosis and contribute to clinical diagnosis and treatment. In addition, we expect to evaluate more EP cases to test our diagnostic criteria and design a systematic diagnostic flow chart.

Hypereosinophilic syndrome with multiorgan involvement: an interdisciplinary work-up

A previously healthy 40-year-old man was referred to our emergency department with pruritic skin lesions and dyspnoea. Laboratory investigation revealed hypereosinophilia. Further diagnostic work-up confirmed the diagnosis of idiopathic hypereosinophilic syndrome (iHES), a rare myeloproliferative disease with a heterogeneous clinical presentation. We describe a unique case with cardiac, pulmonary, hepatic and cutaneous involvement at time of presentation. This case accentuates the importance of an extensive multidisciplinary diagnostic work-up, since iHES is a condition with potential rapid progressive multiorgan failure which requires prompt analysis and treatment. In addition, this case emphasises the importance of being aware of tunnel vision, especially during the COVID-19 pandemic, which might give rise to an increased risk of missing rare diagnoses. Our patient was treated with prednisolone, after which both his clinical condition and eosinophil concentrations markedly improved.

Clinical and morphologic spectrum of renal involvement in idiopathic hypereosinophilic syndrome

BACKGROUND

To explore the clinical and pathological features of renal lesions in patients with kidney involvement in idiopathic hypereosinophilic syndrome (IHES).

METHODS

The demographic, clinical, and pathological characteristics and the treatment and follow-up data were analyzed.

RESULTS

We identified 18 patients with IHES and renal involvement. Eleven patients presented with nephrotic syndrome, and 6 patients had impaired renal function. 15 patients underwent renal biopsy, and the pathological findings included the following: membranoproliferative glomerulonephritis in 3 patients; minimal-change disease in 3; mesangial proliferative nephritis in two; IgA nephropathy in 2; membranous nephropathy in two; chronic interstitial nephritis in two; focal segmental sclerosis in one; and eosinophil infiltration into the renal interstitium in 11 and into the glomerulus in 3. After treatment with glucocorticoids, the eosinophil count decreased. 15 patients were followed up, and 14 showed a decrease in urinary protein or renal function recovery. When glucocorticoids were discontinued, eosinophil increased (8 cases), urine protein increased (1 case), and 1 patient progressed to end-stage renal disease.

CONCLUSIONS

Nephrotic syndrome with or without renal insufficiency is the main clinical manifestation. A wide spectrum of renal lesions can be observed in patients with IHES. Eosinophil infiltration into the renal interstitium was common in these patients. Most patients have a good prognosis after glucocorticoid therapy.

Gene Expression Comparison between Sézary Syndrome and Lymphocytic-Variant Hypereosinophilic Syndrome Refines Biomarkers for Sézary Syndrome

Sézary syndrome (SS), an aggressive cutaneous T-cell lymphoma (CTCL) with poor prognosis, is characterized by the clinical hallmarks of circulating malignant T cells, erythroderma and lymphadenopathy. However, highly variable clinical skin manifestations and similarities with benign mimickers can lead to significant diagnostic delay and inappropriate therapy that can lead to disease progression and mortality. SS has been the focus of numerous transcriptomic-profiling studies to identify sensitive and specific diagnostic and prognostic biomarkers. Benign inflammatory disease controls (e.g., psoriasis, atopic dermatitis) have served to identify chronic inflammatory phenotypes in gene expression profiles, but provide limited insight into the lymphoproliferative and oncogenic roles of abnormal gene expression in SS. This perspective was recently clarified by a transcriptome meta-analysis comparing SS and lymphocytic-variant hypereosinophilic syndrome, a benign yet often clonal T-cell lymphoproliferation, with clinical features similar to SS. Here we review the rationale for selecting lymphocytic-variant hypereosinophilic syndrome (L-HES) as a disease control for SS, and discuss differentially expressed genes that may distinguish benign from malignant lymphoproliferative phenotypes, including additional context from prior gene expression studies to improve understanding of genes important in SS.

Loeffler's Endocarditis and the Diagnostic Utility of Multimodality Imaging

Loeffler’s endocarditis is a rare form of restrictive cardiomyopathy associated with eosinophilia and endomyocardial fibrosis. It manifests most commonly as diastolic dysfunction or valvular abnormalities due to eosinophilic infiltration and degranulation. Herein, we chronicle a case of left ventricular involvement with Loeffler’s endocarditis. We emphasize the utility of multimodality imaging including two-dimensional echocardiography and cardiac magnetic resonance imaging in providing diagnostic information, as there is no standardized diagnostic criteria to date.

Colon perforation due to cytomegalovirus infection in a patient with idiopathic hypereosinophilic syndrome: a case report

Background

Hypereosinophilic syndrome (HES) is a very rare disease and usually treated with corticosteroids. Gastrointestinal (GI) cytomegalovirus (CMV) infection is also rare but frequent in patients with immunocompromised status. These two related diseases present with similar manifestations, and may result in a life-threatening complication: perforation. However, the treatment strategies differ greatly. Here, we report a case of colon perforation due to cytomegalovirus infection in a patient with idiopathic HES.

Case presentation

A 41-year-old man with a history of HES was transferred to our hospital due to an acute onset of abdominal pain. During the treatment course of HES, this patient received CMV-DNA test with a result of < 2000 copies/ml. Computed tomography (CT) suggested colon perforation. An emergency surgery was performed immediately. Pathological diagnosis revealed CMV infection and infiltration of eosinophils. This patient received both anti-CMV therapy and immunosuppression therapy. Subsequently, the patient recovered and was discharged 25 days after the operation.

Conclusion

During the course of HES treatment, CMV infection should be reconsidered if digestive symptoms relapse.

Updates for the treatment of EGPA

Eosinophilic granulomatosis with polyangiitis (EGPA, formerly Churg-Strauss syndrome) is the least frequent antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV). Major advances of our knowledge on its pathophysiology have revealed features of both AAV and eosinophilic disorders. The development of targeted biotherapies for both diseases opened new possibilities for EGPA management. In this review, we highlight the rationale underlying the routine treatment strategy, which relies mainly on corticosteroids, with immunosuppressant adjunction for severe disease. However, novel therapies are still needed for refractory/relapsing disease and to alleviate the corticosteroid-dependence of asthma and chronic rhinosinusitis. At present, the most promising biotherapies target either eosinophil biology, like mepolizumab, an anti-interleukin-5, or the B-cell compartment, with rituximab. Recent clinical data on new treatment options are discussed and therapeutic strategies are proposed.

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.

Hypereosinophilia with Concurrent Venous Thromboembolism: Clinical Features, Potential Risk Factors, and Short-term Outcomes in a Chinese Cohort

Idiopathic hypereosinophilia (IHE) and hypereosinophilic syndrome (HES) are benign haematological disorders. Studies have suggested that venous thromboembolism (VTE) is a rare but sometimes fatal complication of hypereosinophilia; however, data are limited. We retrospectively analysed clinical features and short-term outcomes of 63 consecutive patients (82.5% men; mean age, 40.92 ± 10.89 years) with IHE or HES with concurrent VTE from January 1998 through December 2018. Risk factors for pulmonary embolism (PE) were explored by multivariate logistic analysis. DVT and/or PE was detected by imaging in all patients. Independent risk factors for PE were a body mass index of >24.1 kg/m² (odds ratio [OR]: 5.62, 95% confidence interval [CI]: 1.21–26.13, P = 0.028), peak absolute eosinophil count of >6.3 × 10⁹/L (OR: 5.55, 95% CI: 1.292–23.875, P = 0.021), and >13.9-month duration of hypereosinophilia (OR: 4.51, 95% CI: 1.123–18.09, P = 0.034). All patients were treated with corticosteroids and anticoagulants. The short-term hypereosinophilia remission rate was 100%; no recurrent VTE or major bleeding was observed. Hypereosinophilia is a potential risk factor for VTE. PE in patients with IHE/HES and DVT is associated with a higher body mass index, higher peak absolute eosinophil count, and longer duration of hypereosinophilia. Corticosteroids and anticoagulants provided effective short-term control of hypereosinophilia and VTE.

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.

Interferon-α action in cytokine profile in eosinophilic nasal polyp cultures

Introduction

Chronic rhinosinusitis is currently classified into two types: chronic rhinosinusitis without nasal polyps and chronic rhinosinusitis with nasal polyps. In the West, approximately 80% of chronic rhinosinusitis with nasal polyps cases are characterized by a predominantly eosinophilic cell infiltrate and a Th2 cytokine pattern.

Objective

To evaluate the effect of Interferon-α on cytokine levels of the eosinophilic nasal polyp cell culture supernatant.

Methods

Cell cultures were performed based on nasal polypoid tissue samples collected from 13 patients with eosinophilic chronic rhinosinusitis with nasal polyps. Polyps were considered eosinophilic according to the histopathological examination. Cell cultures were stimulated with 3000 IU of interferon-α. Before and after the stimulus, concentrations of Interferon-γ, tumor necrosis factor αand IL 2, 4, 6 and 10, using cytometric bead array, were assessed.

Results

Cell samples from eosinophilic nasal polyps from 13 patients were included in the study. Twenty-four hours after interferon-α stimulation, eosinophilic nasal polyp culture supernatants showed significantly decreased IL-4 concentrations and increase in interferon-γ, IL-10 and IL-6 concentrations compared to controls. There were no significant differences in tumor necrosis factor -α and IL-2 concentrations.

Conclusion

We demonstrated that interferon-α in vitro alters the pattern of cytokines in cell cultures of eosinophilic nasal polyps. Analysis of these alterations suggests that interferon-α promotes a rebalancing of inflammatory profiles in cell cultures, favoring the expression of Th1 and regulatory cytokines over Th2 cytokines.

Erythrophagocytosis by blasts in a case of de novo acute monoblastic leukemia with rare but characteristic t(8;16)

Erythrophagocytosis by leukemic blasts is a rare phenomenon. We report a case of a female diagnosed with acute monoblastic leukemia with leukemic blasts that were CD34 and CD117 negative, showing erythrophagocytosis, vacoulations, and a rare t(8;16) on bone marrow karyotype which is associated with a poor prognosis despite intensive chemotherapy. Meticulous bone marrow examination in such a scenario may point towards the presence of t(8;16) and help clinicians take a well-informed clinical decision.

Cutaneous adverse drug reactions in patients with peripheral blood eosinophilia during antituberculosis treatment

BACKGROUND/AIMS

Peripheral eosinophilia during tuberculosis (TB) treatment is common, but has not been fully evaluated. The aim of this study was to determine the prevalence and clinical significance of peripheral blood eosinophilia in patients undergoing anti-TB treatment.

METHODS

We retrospectively reviewed the clinical and laboratory data of patients who received anti-TB treatment and had peripheral blood eosinophilia (> 5% of the total white blood cell count) at the Chonnam National University Hospital between January 2010 and December 2014.

RESULTS

Of all 2,234 patients with TB who received anti-TB treatment, 397 (17.8%) had peripheral blood eosinophilia. Of the 397 with eosinophilia, we reviewed the data of 262 (66%), and cutaneous adverse drug reactions (CADRs) were observed in 161 (61.5%). Of the 161 with CADRs, itching (47.2%) and skin rash (47.8%) were common. Older age, abnormal liver function, and higher peak blood eosinophil percentage were associated with CADRs in multivariate analysis. There was a significant relationship between increased peak eosinophil counts and the degree of severity of CADRs.

CONCLUSION

Peripheral blood eosinophilia is a relatively common occurrence during anti-TB treatment. Peripheral blood eosinophil counts were higher according to the degree of severity of CADRs.

Hypereosinophilia and severe bone disease in an African child: an unexpected diagnosis

Hypereosinophilic syndromes are rare in children. Sporadic, mild-severity FIP1L1-platelet-derived growth factor receptor α (PDGFRα) rearrangement cases have been reported, mainly in boys. We present the case of a 5-year-old girl referred from her African country of birth, due to severe constitutional symptoms, multifocal bone pain, headache, gastrointestinal complaints, cardiomyopathy and unexplained hypereosinophilia. She presented multiple end-organ diseases and striking bone involvement. Although she had a positive serology for Strongyloides stercoralis, extensive evaluation detected a FIP1L1-PDGFRA fusion gene. Systemic corticosteroids and low-dose imatinib were started and the child became asymptomatic. After 9 months of treatment, FIP1L1-PDGFRA was no longer detected.

Severe Eosinophilia in Myelodysplastic Syndrome With a Defined and Rare Cytogenetic Abnormality

Myelodysplastic syndromes (MDS) are a heterogeneous group clonal disorders of hematopoietic stem cells (HSC) characterized by ineffective hematopoiesis that lead to variable grades of impaired blood cell production. Chromosomal aberrations are often detected in MDS patients and thus cytogenetic analysis is useful for the diagnosis of these disorders. Common recurring chromosomal defects, such as the −5/5q- and −7/7q- are relatively well characterized cytogenetic abnormalities in MDS, however, the biological significance of uncommon cytogenetic alterations is unknown. We report here, two cases of peripheral blood and bone marrow hypereosinophilia in patients with MDS harboring the unbalanced translocation der(1;7)(q10;p10), a poorly characterized cytogenetic abnormality that is found in certain myeloid malignancies, including MDS. The patients reported here presented hypereosinophilia that was refractory to steroids and cytotoxic therapy, leading to severe target tissue damage that ultimately resulted in fatal end-organ failure. Potential roles of the der(1;7)(q10;p10) aberrations in the pathogenesis of aggressive eosinophilia and disease prognosis are discussed here.

Idiopathic Purpura With Gray Platelets: an Acquired Form of Gray Platelet Syndrome

An acquired, transient bleeding disorder that predominantly affects children in Southeast Asia has been reported for the last 4 decades. The condition has been named idiopathic purpura with gray platelets (IPGP) or acquired platelet dysfunction with eosinophilia. In a retrospective review from a private pediatric clinic over an 8-year period, 10 consecutive children were diagnosed as IPGP with a mean age of 8.4 (3.7 to 16.2) years. Eosinophilia (>0.5×10/L) was absent in 1, while gray platelets were consistently found in all cases with a mean proportion of 64.5% (40% to 80%). Platelet aggregation tests were performed in 9 patients with abnormal responses consistent with platelet storage pool defect. All children recovered completely and spontaneously from 1 to 4 months after diagnosis without specific therapy. In an otherwise well child who presents abruptly with easy bruising and a platelet count >100×10/L, IPGP can be readily recognized as an acquired form of gray platelet syndrome. Eosinophilia is common but not mandatory for diagnosis.

Idiopathic hypereosinophilic syndrome with cutaneous involvement: a comparative review of 32 cases

Although idiopathic hypereosinophilic syndrome (HES) is uncommon, we studied the clinical characteristics of this disorder in patients with cutaneous involvement. We chronicle the case of a patient with diffuse skin rash due to idiopathic HES from our clinical experience. Furthermore, a systematic literature search of the medical databases PubMed and Google Scholar was conducted. A total of 32 cases fulfilled the inclusion criteria. The data on patients' characteristics, epidemiology, clinical features, diagnosis, treatment and outcome were collected and analysed. This review illustrates that physicians should maintain a high index of clinical suspicion for idiopathic HES in patients presenting with dermatological lesions and hypereosinophilia, without an obvious cause. Randomised clinical trials are warranted to outline a generalised and efficient therapeutic approach in these patients. Additionally, this paper highlights the need for population-based studies to delineate the magnitude and scope of this association.

A multimodality work-up of patients with Hypereosinophilia

The work-up of patients with hypereosinophilia (HE) is complex. Following the recently revised World Health Organization criteria, we retrospectively reviewed 125 patients who were referred to us to exclude a neoplastic cause of HE (2003-2016). The clinical laboratory work-up confirmed secondary HE in 25 (20%) patients; myeloid/lymphoid neoplasms with rearrangements of PDGFRA (n = 9) or PDGFRB (n = 2) (9%); HE associated with a well-defined myeloid neoplasm in 8 (6%); and abnormal bone marrow and/or molecular genetic abnormalities consistent with chronic eosinophilic leukemia (CEL), not otherwise specified (NOS) in 21 (17%) patients. For the remaining 60 (48%) patients, a specific diagnosis was not identified, and 56 patients had HE related findings consistent with idiopathic hypereosinophilic syndrome (HES), while 4 patients who were asymptomatic. With a median follow up of 35.3 months (range, <1-104), patients with CEL, not otherwise specified (NOS) had a median OS of 26.1 months, significantly inferior to patients with idiopathic HES (not reached, P < .01). Thus, our experience in a single tertiary cancer center shows that the work-up of HE following WHO recommendations requires a multimodality-based approach; and a correct diagnosis determines risk stratification and proper patient management. However, the causes of HE remain unknown in approximately half of referred patients, indicating the need for further studies.

A Test Utilization Approach to the Diagnostic Workup of Isolated Eosinophilia in Otherwise Morphologically Unremarkable Bone Marrow: A Single Institutional Experience

OBJECTIVES

Determine ancillary test utilization for the workup of isolated eosinophilia in otherwise morphologically unremarkable bone marrow (BM).

METHODS

We evaluated BM ancillary testing performed in cases with isolated eosinophilia and otherwise morphologically unremarkable BM. Cases with abnormal morphology (eg, dysplasia, basophilia) and/or findings suggestive of a disorder (eg, unexplained thromboses, lymphoma) are specifically excluded.

RESULTS

A total of 132 cases met inclusion criteria. Ten cases had an ancillary testing abnormality that warranted a more specific hematologic diagnosis: four cases of lymphocytic variant of hypereosinophilic syndrome, three cases of myeloid neoplasm with PDGFRA rearrangement, and one case each of myeloid neoplasm with PDGFRB rearrangement, chronic eosinophilic leukemia, and morphologically occult systemic mastocytosis. No cases revealed a cryptic PDGFRB or BCR/ABL1 rearrangement or JAK2 V617F mutation.

CONCLUSIONS

Findings from our institutional experience support initial testing in isolated eosinophilia with otherwise unremarkable BM to include PDGFRA rearrangement, tryptase/CD25 immunohistochemistry, cytogenetics, and T-cell flow cytometry/receptor gene rearrangement. This approach achieves diagnostic quality and test utilization efficiency in our clinical practice.

Endomyocardial Fibrosis With End-Stage Heart Failure as a Consequence of a Myeloproliferative Neoplasm With Hypereosinophilia

Hypereosinophilic syndrome is characterized by an overproduction of eosinophils that infiltrate and damage multiple organs. Cardiac dysfunction occurs frequently and is a main cause of morbidity and mortality. We describe the case of a middle-aged man diagnosed with a myeloproliferative neoplasm associated with hypereosinophilia and treated with imatinib. He was diagnosed with cardiac involvement by hypereosinophilic syndrome at a late stage, with an established restrictive cardiomyopathy. Because of end-stage heart failure, he successfully received a heart transplant. This disease might not be considered a contraindication for heart transplantation.

FIP1L1-PDGFRA fusion-negative hypereosinophilic syndrome with uncommon cardiac involvement responding to imatinib treatment: A case report

Hypereosinophilic syndrome is a rare, chronic hematological disease characterized by a persistently elevated eosinophil count exceeding 1.5×10⁹/l, following the exclusion of other potential etiologies. The systemic involvement of the disease causes tissue damage through eosinophil infiltration, and may affect various organs; cardiac complications are observed in 50-60% of cases, which are predominately attributed to endomyocardial fibrosis. The treatment is based initially on determining the presence of the FIP1L1-PDGFRA fusion. Patients with positive results for this mutation tend to achieve a complete response with imatinib treatment, which is thus the first line of treatment for this condition. However, patients who are negative for this mutation initially undergo treatment with corticosteroids. This study reports the case of a male 53-year-old patient diagnosed with hypereosinophilic syndrome in 2012, with negative results for the FIP1L1-PDGFRA mutation, and persistently high eosinophil levels, despite receiving the second line of standard treatment for this condition with hydroxyurea, and having already used corticosteroids without success. At the time of admission, the patient presented with acute decompensated heart failure due to severe mitral regurgitation, without any evidence of prior myocardial fibrosis or restrictive cardiomyopathy, and without suggestion of an associated ventricular hypertrophy. This clinical presentation is uncommon, as valvular involvement usually appears in the third stage of the development of cardiac involvement, and is usually associated with fibrosis and thrombotic events. Alternative therapeutic possibilities were evaluated due to the significant progression of the disease, and it was decided to attempt the use of imatinib, despite its use being preferably recommended for FIPIL1-PDGFRA-positive patients. The patient exhibited an evident and immediate response to imatinib, with normalization of the eosinophil count within 24 h of the first dose, which was maintained for at least the next 19 months. This clinical presentation is uncommon, as patients negative for FIPIL1-PDGFRA fusion do not frequently respond to imatinib treatment, and symptomatic heart failure usually appears in the third stage of disease progression.

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.

Oncogenic kinase fusions: an evolving arena with innovative clinical opportunities

Cancer biology relies on intrinsic and extrinsic deregulated pathways, involving a plethora of intra-cellular and extra-cellular components. Tyrosine kinases are frequently deregulated genes, whose aberrant expression is often caused by major cytogenetic events (e.g. chromosomal translocations). The resulting tyrosine kinase fusions (TKFs) prompt the activation of oncogenic pathways, determining the biological and clinical features of the associated tumors. First reported half a century ago, oncogenic TKFs are now found in a large series of hematologic and solid tumors. The molecular basis of TKFs has been thoroughly investigated and tailored therapies against recurrent TKFs have recently been developed. This review illustrates the biology of oncogenic TKFs and their role in solid as well as hematological malignancies. We also address the therapeutic implications of TKFs and the many open issues concerning their clinical impact.

CT and MRI findings in focal eosinophilic infiltration of the liver

OBJECTIVES

To investigate the findings of computed tomography (CT) and magnetic resonance imaging (MRI) of focal eosinophilic infiltration (FEI) of the liver.

METHODS

A retrospective study including 29 patients with confirmed FEI of the liver was performed. We evaluated the lesions' number, distribution, size, shape, margin, attenuation or signal intensity characteristics, the enhancement pattern, and some special features. Spearman correlation analysis was used to analyze the correlation between the number of lesions and the eosinophil counts in peripheral blood.

RESULTS

In all, 108 lesions were detected in 29 cases, including two cases with single lesion and the remaining 27 cases with multiple lesions. The mean size of all lesions was 34 mm (range, from 3 to 61 mm). 95 (88%) lesions were located in subcapsular parenchyma or surrounding the portal vein. Most (66%) subcapsular lesions were wedge shaped and all lesions surrounding portal vein were round shaped. However, the hepatic parenchymal lesions were irregular or round shaped. All lesions showed ill-defined margins. On pre-contrast CT images, the lesions showed slightly low attenuation or iso-attenuating. On T1-weighted and T2-weighted images, the lesions were slightly iso-/hypointense and hyperintense, respectively. A total of 23 (79.3%) cases were gradually enhanced. Branches of portal vein went through the lesions in all cases; 12 had 'stripe sign' and 16 had 'halo ring sign.' Spearman analysis indicated a significant correlation between the number of lesions and the increased eosinophils in peripheral blood (r = 0.627, p = 0.0003).

CONCLUSIONS

Special CT and MRI features and increased eosinophils may strongly suggest the diagnosis of FEI of the liver.

Idiopathic hypereosinophilia is clonal disorder? Clonality identified by targeted sequencing

Idiopathic hypereosinophilia (IHE)/idiopathic hypereosinophilic syndrome (IHES) has been defined by a persistent elevation of the blood eosinophil count exceeding 1.5×10³/μL, without evidence of reactive or clonal causes. While T-cell clonality assessment has been recommended for unexplained hypereosinophilia, this approach is not often applied to routine practice in the clinic. We hypothesized that the clonality would exist in a subset of IHE/IHES patients. We aimed to investigate the candidate mutations and T-cell clonality in IHE/IHES and to explore the role of mutations in eosinophil proliferation. We performed targeted capture sequencing for 88 genes using next-generation sequencing, T-cell receptor (TCR) gene rearrangement assays, and pathway network analysis in relation to eosinophil proliferation. By targeted sequencing, 140 variants in 59 genes were identified. Sixteen out of 30 patients (53.3%) harbored at least one candidate mutation. The most frequently affected genes were NOTCH1 (26.7%), SCRIB and STAG2 (16.7%), and SH2B3 (13.3%). Network analysis revealed that our 21 candidate genes (BIRC3, BRD4, CSF3R, DNMT3A, EGR2, EZH2, FAT4, FLT3, GATA2, IKZF, JAK2, MAPK1, MPL, NF1, NOTCH1, PTEN, RB1, RUNX1, TET2, TP53 and WT1) are functionally linked to the eosinophilopoietic pathway. Among the 21 candidate genes, five genes (MAPK1, RUNX1, GATA2, NOTCH1 and TP53) with the highest number of linkages were considered major genes. A TCR assay revealed that four patients (13.3%) had a clonal TCR rearrangement. NOTCH1 was the most frequently mutated gene and was shown to be a common node for eosinophilopoiesis in our network analysis, while the possibility of hidden T cell malignancy was indwelling in the presence of NOTCH1 mutation, though not revealed by aberrant T cell study. Collectively, these results provide new evidence that mutations affecting eosinophilopoiesis underlie a subset of IHE/IHES, and the candidate genes are inferred to act their potential roles in the eosinophilopoietic pathway.

Tyrosine Kinase Inhibitors in the Treatment of Eosinophilic Neoplasms and Systemic Mastocytosis

The World Health Organization's semimolecular classification of eosinophilias emphasizes neoplasms driven by fusion tyrosine kinases. More than 80% of patients with systemic mastocytosis carry the KIT D816V mutation, the primary driver of disease pathogenesis. Genetic annotation of these diseases is critical and affords opportunities for targeted therapy. This article discusses our understanding of the mutated tyrosine kinome of eosinophilic neoplasms and systemic mast cell disease, and the successes and limitations of available therapies. Use of tyrosine kinase inhibitors as a bridge to hematopoietic stem cell transplantation, and development of more selective and potent tyrosine kinase inhibitors is also highlighted.

How I Diagnose Hypereosinophilic Syndromes

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