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

11-Year-Old Boy With B-ALL-Induced Hypereosinophilic Syndrome Presenting as Acute Encephalopathy

Encephalopathy is a disturbance in neurologic function. It is commonly attributed to infectious and inflammatory etiologies but encompasses a wide differential. Hypereosinophilic syndrome (HES) is a rare cause of encephalopathy that is associated with underlying infection or malignancy. We present a pediatric patient who experienced several days of worsening encephalopathy and neurological deterioration associated with influenza B infection and hypereosinophilia. A thorough workup ultimately revealed a diagnosis of HES secondary to B cell acute lymphoblastic leukemia (B-ALL). This case exemplifies the importance of maintaining a broad approach to the diagnostic evaluation, treatment, and management of encephalopathy.

Exploring the Dynamics of Immune Checkpoint Inhibitor-Induced Eosinophilia in Advanced/Metastatic Melanoma: A Comprehensive Retrospective Analysis

BACKGROUND

Immune-related eosinophilia has emerged as an adverse event associated with immune checkpoint inhibitors (ICIs). Its prevalence, severity, duration, clinical significance, diagnostic approach, and management remain unexplored.

METHODS

We conducted a retrospective review of melanoma patient records at a university referral center. Our analysis encompassed the incidence of eosinophilia, baseline disease characteristics, treatment modalities, peak eosinophil counts, associated symptoms, diagnostic procedures, management strategies, disease course, and prognostic implications.

RESULTS

A total of 308 patients were included. Eosinophilia was present in 21.4%, and there was no association with gender, age, histologic type, stage, or BRAF mutation status. The median time interval from treatment initiation to the eosinophilia onset was 56 days, the median eosinophil count at first presentation was 0.70 × 109/L, and the maximum eosinophil count was 1.02 × 109/L. The rate of eosinophilia was significantly higher in patients treated with nivolumab plus bempegaldesleukin (50.0%), followed by nivolumab plus ipilimumab (21.7%). Symptomatic patients and/or patients with hypereosinophilia were assessed for organ involvement and for the identification of the cause of eosinophilia. Patients requiring medical intervention were managed with corticosteroids or antihistamines. Eosinophilia relapsed in 31.8% when rechallenged. While non-significant, there was a numeric trend for longer overall survival in patients with eosinophilia (42.6 vs. 27.9 months, p = 0.178).

CONCLUSIONS

This study marks the first comprehensive approach of the relationship between the type of immunotherapy and the incidence of eosinophilia in melanoma patients. It also delves into the patients' baseline characteristics, diagnostic assessment, management, and prognosis, providing useful guidance for physicians treating patients with ICIs.

Hypereosinophilia and Hypereosinophilic Syndromes: First Findings From a Nationwide Multicenter Cohort

BACKGROUND

Hypereosinophilic syndromes (HES) are a heterogenous group of eosinophilic disorders. To date, only retrospective studies of limited sample-size and/or follow-up duration are available.

METHODS

The COHESion study is a national prospective multicenter multidisciplinary cohort recruiting both adults or children with the spectrum of eosinophilic disorders (including reactive HE/HES [HE/HES-R], idiopathic HES [HES-I], lymphocytic HES [HES-L], neoplastic HE/HES [HE/HES-N], HE of unknown significance [HE-US], as well as IgG4-related disease [IgG4RD] or ANCA-negative eosinophilic granulomatosis with polyangiitis [EGPA] overlaps). Patients are followed-up yearly. All data about final diagnosis, organ involvement assessments, and outcome profiles in HES-I were captured and analyzed centrally by HES expert centers.

RESULTS

From May 2019 to November 2023, 779 patients were included. For this preliminary analysis, 550 cases were available for centralized review (mean ± SD age: 56 ± 18 years, 42% of female patients). The final diagnoses were HES-I (47%), HE/HES-R (16%), HE-US (15%), HE/HES-N (7%), HE/HES-L (6%), IgG4RD (2%), and ANCA-negative EGPA (7%). In the 258 HES-I patients, outcome profiles were classified as follows: 16.3% had a "single-flare" without further relapse, 28.3% had a "relapsing-remitting" disease when there was at least a 6-month period free of symptoms between two flares, 46.1% had a "persistent disease" requiring continuous treatment to avoid relapses (9.3% remained unclassified because of insufficient follow-up).

CONCLUSIONS

The COHESion cohort is the first nationwide prospective multicenter study collecting data on the full spectrum of HE/HES disorders. This preliminary analysis confirms that idiopathic HES patients have various outcome profiles, suggesting different underlying pathophysiological mechanisms and the need of patient-specific management.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04018118.

Malignant JAK-signaling: at the interface of inflammation and malignant transformation

The JAK pathway is central to mammalian cell communication, characterized by rapid responses, receptor versatility, and fine-tuned regulation. It involves Janus kinases (JAK1, JAK2, JAK3, TYK2), which are activated when natural ligands bind to receptors, leading to autophosphorylation and activation of STAT transcription factors [1, 2]. JAK-dependent signaling plays a pivotal role in coordinating cell communication networks across a broad spectrum of biological systems including development, immune responses, cell growth, and differentiation. JAKs are frequently mutated in the aging hematopoietic system [3, 4] and in hematopoietic cancers [5]. Thus, dysregulation of the pathway results in various diseases, including cancers and immune disorders. The binding of extracellular ligands to class I and II cytokine receptors initiates a critical signaling cascade through the activation of Janus kinases (JAKs). Upon ligand engagement, JAKs become activated and phosphorylate specific tyrosine residues on the receptor, creating docking sites for signal transducer and activator of transcription (STAT) proteins. Subsequent JAK-mediated phosphorylation of STATs enables their dimerization and nuclear translocation, where they function as transcription factors to modulate gene expression. Under physiological conditions, JAK-signaling is a tightly regulated mechanism that governs cellular responses to external cues, such as cytokines and growth factors, ensuring homeostasis and maintaining the functional integrity of tissues and organs. Highly defined regulation of JAK-signaling is essential for balancing cellular responses to inflammatory stimuli and growth signals, thus safeguarding tissue health. In contrast, dysregulated JAK-signaling results in chronic inflammation and unrestrained cellular proliferation associated with various diseases. Understanding the qualitative and quantitative differences at the interface of physiologic JAK-signaling and its aberrant activation in disease is crucial for the development of targeted therapies that precisely tune this pathway to target pathologic activation patterns while leaving homeostatic processes largely unaffected. Consequently, pharmaceutical research has targeted this pathway for drug development leading to the approval of several substances with different selectivity profiles towards individual JAKs. Yet, the precise impact of inhibitor selectivity and the complex interplay of different functional modules within normal and malignant cells remains incompletely understood. In this review, we summarize the current knowledge on JAK-signaling in health and disease and highlight recent advances and future directions in the field.

Eosinophil-Driven vs. Eosinophil-Associated Severe Asthma: Practical Implications for Target Treatment

Severe asthma (SA) is a chronic inflammatory condition affecting approximately 10% of asthmatic patients, and eosinophils are considered key pathogenetic actors in a significant number of patients. Biological therapies have been demonstrated to improve asthma control by decreasing exacerbation rates and reducing the use of oral corticosteroids. In this context, phenotyping and endotyping patients with SA is essential for selecting the most effective therapeutic approach. For this purpose, biomarkers such as IgE, absolute blood eosinophil count, and fractional exhaled nitric oxide (FeNO) are crucial in defining a patient's inflammatory profile. Their integration provides a framework for classifying asthma into T2-high, T2-mild, or T2-low categories, guiding personalized treatment strategies. By incorporating multiple biomarkers into a unified model, it is possible to better stratify patients and optimize biologic therapy selection, paving the way for improved outcomes in SA management. This review aims to evaluate the role of phenotyping and endotyping SA patients, with particular attention to the impact of eosinophilic inflammation and combinatory biomarkers on decision-making processes for the selection of biological therapies.

Profiling Blood Hypereosinophilia in Patients on Dupilumab Treatment for Respiratory Conditions: A Real-Life Snapshot

BACKGROUND

A transient and usually asymptomatic increase in blood eosinophil count (BEC) associated with dupilumab treatment has been described. Predicting factors related to the increase in BEC and the occurrence of symptoms are still poorly investigated.

OBJECTIVE

To investigate frequency, timing, duration, clinical relevance, and potential predictors of the increase in BEC in a real-life multicenter cohort of patients affected by asthma and/or chronic rhinosinusitis with nasal polyps (CRSwNP) treated with dupilumab.

METHODS

BEC and clinical conditions at baseline and every 3 months after the start of dupilumab treatment were assessed. Any adverse drug reaction was also recorded. Remission of dupilumab-associated eosinophilia was defined by follow-up BEC values <0.5 × 109 cells/L.

RESULTS

Overall, 108 of 195 (55%) patients experienced an increased BEC after dupilumab initiation, but only 29 of 195 (14.9%) showed hypereosinophilia. BEC peak occurred 6 months after the start of treatment and resolved after 9 months (median time). The probability of developing hypereosinophilia was 3.3 times higher in patients with the baseline BEC between 0.5 × 109 and 1.5 × 109 cells/L. The occurrence of symptoms during BEC peak was higher in patients with comorbidities and in patients showing any increase in BEC.

CONCLUSIONS

In a real-life setting, dupilumab treatment in patients with asthma and/or CRSwNP was often associated with a transient increase in BEC, but hypereosinophilia rarely occurred. Onset of symptoms co-occurring with BEC peak was observed in a minority of subjects. BEC should not preclude dupilumab initiation or continuation but should be monitored for at least 8 months after treatment begins, particularly in the case of baseline eosinophilia/hypereosinophilia and/or comorbidities.

Head and Neck Classic Hodgkin, T and NK Lymphomas with Eosinophilia

Eosinophilia is a notable feature in various hematological malignancies, including specific types of leukemias and lymphomas that may occur in the head and neck. In hematologic malignancies, eosinophilia can be primary, driven by genetic abnormalities, or secondary, resulting from cytokine and chemokine production by the neoplastic cells or the tumor microenvironment. This review examines the association between eosinophilia and head and neck hematolymphoid malignancies including Classic Hodgkin lymphoma, T-cell lymphoblastic leukemia, mature T and NK-cell lymphomas, and Langerhans cell histiocytosis. It explores the underlying mechanisms of eosinophilia in these malignancies, highlighting the role of chemokines and cytokines such as IL-5, TARC, and eotaxin. Recognition of eosinophilia may aid in the diagnosis of these conditions and understanding the mechanisms of eosinophilia may provide insights into potential prognostic implications and treatment strategies.

Case Report: Loeffler endocarditis as a cause of left ventricular thrombosis in young women: a case study and literature review

It is unusual for young patients without any underlying diseases to experience sudden cerebral infarction and heart failure. Here, we report a rare case of a 28-year-old female patient who presented with chest tightness and dizziness. Left ventricular thrombus formation and cardiac insufficiency were evident on echocardiogram, while multiple acute or subacute cerebral infarctions were visible on brain magnetic resonance imaging. We preliminarily determined that this was a different manifestation of the same disease. After investigating the cause, we diagnosed the patient with Loeffler endocarditis caused by idiopathic eosinophilia syndrome involving the heart. Although no endocardial biopsy was performed, this diagnosis was confirmed through cardiac magnetic resonance imaging (CMR). After drug treatment consisting of corticosteroids and anticoagulants, the eosinophil count decreased significantly; however, the thrombus did not completely disappear, as assessed in multiple follow-up echocardiogram sessions. Further exploration of the tissue composition of the patient's left ventricular mass suggested that the mass was a mixture of thrombus and eosinophilic granulation tissue. The addition of imatinib to the treatment plan had a good therapeutic effect, and the patient's left ventricular mass completely disappeared. Loeffler endocarditis progresses rapidly and requires early identification and intervention by clinicians. This case emphasizes that, despite the lack of an endocardial biopsy, the early diagnosis of Loeffler endocarditis can be made through CMR, while avoiding the occurrence of irreversible endocardial fibrosis. We also explored the nature of the patient's cardiac mass and proposed different insights. The nature of cardiac mass varies in different stages of Loeffler endocarditis, and individualized treatment strategies are needed.

Successful novel use of dupilumab for gastrointestinal involvement of idiopathic hypereosinophilic syndrome: case report and review of the literature

Hypereosinophilic syndrome (HES) is characterized by blood and tissue hypereosinophilia leading to organ damage. Gastrointestinal involvement is the third most common manifestation. We present a patient with idiopathic HES with secondary eosinophilic esophagitis (EoE), gastritis, and enteritis, corticosteroids-dependent, azathioprine- and mepolizumab-refractory. The patient achieved clinical and histopathologic remission following dupilumab treatment. A 28 year-old female presented with chronic episodic nausea and emesis since childhood and initial diagnosis of primary eosinophilic gastrointestinal disease (EGID), improved with corticosteroids, refractory to azathioprine. She was found to have peripheral eosinophilia and multifactorial anemia, with iron, B12, and folate deficiencies. Esophageal, gastric, duodenal, and terminal ileum biopsies showed significant eosinophilic infiltrate. Bone marrow biopsy at age 31 confirmed HES diagnosis. By age 32, she became total parental nutrition (TPN)-dependent. She failed trials of benralizumab and mepolizumab [anti-interleukin (IL)-5 inhibitors], and cromolyn (mast-cell stabilizer). After developing new esophageal stricture, we initiated dupilumab (IL-4/13 inhibitor), recently FDA-approved for EoE. After 9 weeks, esophageal stricture, gut tissue eosinophilia, and prior intestinal ulcerations resolved. She ceased TPN and is tolerating a non-restricted diet, with complete symptom resolution. Our patient's complete remission with dupilumab shows promise for broadening its use in treating GI involvement in HES, along with primary EGIDs.

Eosinophilic myocarditis: from etiology to diagnostics and therapy

Eosinophilic myocarditis (EM) is a rare, potentially life-threatening, form of inflammatory heart disease characterized by eosinophilic infiltration of the myocardium. Different diseases are involved in its etiopathogeneses, such as eosinophilic granulomatosis with polyangiitis (or Churg-Strauss Syndrome), hypereosinophilic syndromes, parasitic infections, drug reactions, paraneoplastic syndromes and primary immunodeficiencies (e.g. Omenn Syndrome). There is a wide spectrum of clinical pictures at presentation ranging from chronic restrictive cardiomyopathy (Loeffler cardiomyopathy) to acute necrotizing myocarditis with cardiogenic shock. The genetic contribution and the environmental interplay, such as SARS-CoV-2 infection and related vaccines, are fields not well studied yet. Many non-invasive tools, mainly echocardiography and cardiac magnetic resonance imaging, along with invasive procedures, such as endomyocardial biopsy, are the crucial steps in the diagnostic workup. The correct diagnosis is a challenge but mandatory for timely and appropriate immunosuppressive therapy.

Imatinib is effective in some PDGFRA/B-negative hypereosinophilic syndromes: A step closer to unveiling underlying mechanisms

Hypereosinophilic syndromes (HES) comprise different clonal, reactive, or idiopathic disorders characterized by elevated eosinophil levels and subsequent organ damage. Kim et al. in a multicentre, single-arm, prospective phase II study, treated 32 patients with PDGFRA/B-negative HES with imatinib at the dose of 100-400 mg daily. Respective overall and complete haematological response rates were 46.9% and 18.8%, and the median time to response was 1.5 months. The molecular basis of responses was identified by using whole-exome and whole-transcriptome sequencing in 11 patients. STAT5B::RARA, PAK2::PIGX, and FIP1L1::CHIC2 fusions were identified in responders, whereas RNF130::BRAF and WNK1::KDM5A were identified in non-responders. Imatinib could be a therapeutic option for some, possibly clonal, PDGFRA/B-negative HES. Commentary on: Kim et al. Phase II trial of imatinib mesylate in patients with PDGFRA/B-negative hypereosinophilic syndrome. Br J Haematol 2024; 205:2305-2314.

Delineation of features, responses, outcomes, and prognostic factors in pediatric PDGFRB-positive acute lymphoblastic leukemia patients: A retrospective multicenter study

BACKGROUND

PDGFRB fusions in acute lymphoblastic leukemia (ALL) is rare. The authors identified 28 pediatric PDGFRB-positive ALL. They analyzed the features, outcomes, and prognostic factors of this disease.

METHODS

This multicenter, retrospective study included 6457 pediatric patients with newly diagnosed PDGFRB fusion ALL according to the CCCG-ALL-2015 and CCCG-ALL-2020 protocols from April 2015 to April 2022 in 20 hospitals in China. Of these patients, 3451 were screened for PDGFRB fusions.

RESULTS

Pediatric PDGFRB-positive ALL accounted for only 0.8% of the 3451 cases tested for PDGFRB. These patients included 21 males and seven females and 24 B-ALL and 4 T-ALL; the median age was 10 years; and the median leukocyte count was 29.8 × 109/L at baseline. Only one patient had eosinophilia. Three patients had an IKZF1 deletion, three had chromosome 5q31-33 abnormalities, and one suffered from a complex karyotype. The 3-year event-free survival (EFS), overall survival (OS), and cumulative incidence of relapse (CIR) were 33.1%, 65.5%, and 32.1%, respectively, with a median follow-up of 25.5 months. Twenty patients were treated with chemotherapy plus tyrosine-kinase inhibitors (TKIs) and eight were treated without TKI. Complete remission (CR) rates of them were 90.0% and 63.6%, respectively, but no differences in EFS, OS, or CIR. Univariate analyses showed patients with IKZF1 deletion or measurable residual disease (MRD) ≥0.01% after induction had inferior outcomes (p < .05).

CONCLUSIONS

Pediatric PDGFRB-positive ALL has a poor outcome associated with high-risk features. Chemotherapy plus TKIs can improve the CR rate, providing an opportunity for lower MRD levels and transplantation. MRD ≥0.01% was a powerful adverse prognostic factor, and stratified treatment based on MRD may improve survival for these patients.

PLAIN LANGUAGE SUMMARY

Pediatric acute lymphoblastic leukemia patients with PDGFRB fusions are associated with high-risk clinical features such as older age, high white blood cell count at diagnosis, high measurable residual disease after induction therapy, and increased risk of leukemia relapse. Chemotherapy plus tyrosine-kinase inhibitors can improve the complete remission rate and provide an opportunity for lower measurable residual disease (MRD) levels and transplantation for pediatric PDGFRB-positive acute lymphoblastic leukemia (ALL) patients. The MRD level was also a powerful prognostic factor for pediatric PDGFRB-positive ALL patients.

Non-episodic angioedema with eosinophilia as a differential diagnosis of eosinophilia in young females

Background

Episodic angioedema with eosinophilia, also known as Gleich's syndrome, is a differential diagnosis in patients with recurrent angioedema with higher blood eosinophils. Meanwhile, less has been elucidated regarding non-episodic angioedema with eosinophilia (NEAE). This study aimed to examine the prevalence, clinical characteristics, and disease course of NEAE.

Methods

By reviewing the electronic medical records, we identified patients with NEAE among those referred to allergy clinics due to eosinophilia from January 2021 to December 2023 at Asan Medical Center.

Results

Among 687 patients with eosinophilia, 58 (8.4%) were diagnosed with and treated for NEAE. All patients were females, with a mean age of 31.79 years. The mean absolute blood eosinophil count was 4468.76 cells/μL. All patients reported symmetric angioedema of the lower legs, and 37 (63.8%) had additional angioedema of the upper arms. Twenty-five (43.1%) patients reported a preceding event prior to onset of angioedema. Systemic corticosteroids (mean total dose 1745 ± 508.49 mg) were prescribed to all patients, with a treatment duration of approximately 40 days to achieve resolution. Following the resolution of angioedema, 6 patients experienced persistent arthralgia, 1 developed chronic spontaneous urticaria, and 1 developed hypereosinophilic syndrome.

Conclusions

NEAE is an essential differential diagnosis in young female patients with eosinophilia, particularly those presenting with symmetric peripheral angioedema.

A Storm of Polyserositis: Unravelling Multisystem Effusions in Hypereosinophilic Syndrome

Idiopathic hypereosinophilic syndrome (i-HES) is a rare disorder characterized by persistent eosinophilia and organ involvement, without an identifiable secondary cause. This case report describes a 42-year-old man with no significant medical history, who initially presented with symptoms resembling community-acquired pneumonia, including fever, shortness of breath, and pleuritic chest pain. Despite antibiotic treatment, his condition rapidly progressed to polyserositis, characterized by bilateral pleural effusions, pericardial tamponade, and ascites. Extensive diagnostic evaluation excluded the secondary causes of hypereosinophilia, leading to a final diagnosis of i-HES. Prompt initiation of high-dose corticosteroids resulted in dramatic clinical improvement, with resolution of the fever, pleural effusion, and pericardial effusion. This case highlights the diagnostic challenges associated with the atypical presentations of i-HES and emphasizes the importance of early recognition, comprehensive evaluation, and appropriate corticosteroid therapy. It also raises awareness of the potential for i-HES to present with life-threatening complications, underscoring the need for multidisciplinary management.

Targeted inhibition of the IL5 axis for immune checkpoint inhibitors eosinophilic-induced adverse events

Given the broad implementation of immune checkpoint inhibitors (ICI) for cancer therapy, we encounter a variety of immune-related adverse events (irAE) including immune-related blood eosinophilia. Eosinophilia demonstrated a potential positive predictive marker for a beneficial clinical response to ICI. However, there are reports of eosinophil-induced adverse events (Eo-irAE) with organ dysfunction requiring initiation of oral glucocorticoid therapy and discontinuation of ICI.We aim to assess the efficacy and safety of interleukin (IL) 5-axis inhibition in Eo-irAE secondary to ICI therapy.We present three cases of Eo-irAE referred to our allergy and clinical immunology unit at Hadassah Hebrew University Medical Center following therapy with pembrolizumab and nivolumab, monoclonal antibodies that target the programmed cell death 1 (PD-1) receptor, for two cases of melanoma and one metastatic non-small cell lung carcinoma. Following informed consent and committee approval, two patients were treated with 1-3 doses of mepolizumab, 100 mg, monoclonal IgG1 kappa anti-IL-5 antibody, and one patient received up-to-date 9 doses of benralizumab, 30 mg, monoclonal IgG1 kappa antibody directed against the alpha chain of the interleukin-5 receptor, both administered subcutaneously. Patients were carefully followed and treatment response was assessed by physical examinations and laboratory tests.Hypereosinophilia at the level of 2300-8000 K/UL was observed 8-12 months following therapy accompanied by symptoms of dyspnea, arthralgia, myalgia, fasciitis, 'morphea'-like lesions, fatigue, abdominal discomfort, pruritus, and chest pain. ICI discontinuation did not improve symptoms, two patients were resistant to glucocorticoids and therefore biological treatment was initiated to inhibit the IL5 axis. Patients demonstrated rapid clinical response and a decrease in peripheral blood eosinophil levels with long-term symptoms remission. There were no signals of negative impacts, such as tumor progression following IL5 axis inhibition.Eosinophilia secondary to ICI therapy can lead to organ dysfunction. Discontinuation of ICI might not be effective and symptoms may be refractory to steroid therapy hence targeted inhibition of the IL5 axis should be considered.

Cardiac Abnormalities in Hypereosinophilic Syndromes

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

Red flags for clinical suspicion of eosinophilic granulomatosis with polyangiitis (EGPA)

BACKGROUND

Eosinophilic granulomatosis with polyangiitis (EGPA), is a rare ANCA-associated systemic vasculitis. Its overlapping features with other vasculitic or eosinophilic diseases, and the wide and heterogeneous range of clinical manifestations, often result in a delay to diagnosis.

OBJECTIVE

To identify red flags that raise a suspicion of EGPA to prompt diagnostic testing and to present an evidence-based clinical checklist tool for use in routine clinical practice.

METHODS

Systematic literature review and expert consensus to identify a list of red flags based on clinical judgement. GRADE applied to generate a strength of recommendation for each red flag and to develop a checklist tool.

RESULTS

86 studies were included. 40 red flags were identified as relevant to raise a suspicion of EGPA and assessed by the experts as being clinically significant. Experts agreed that a diagnosis of EGPA should be considered in a patient aged ≥6 years with a blood eosinophil level >1000 cells/µL if untreated and >500 cells/µL if previously treated with any medication likely to have altered the blood eosinophil count. The presence of asthma and/or nasal polyposis should reinforce a suspicion of EGPA. Red flags of asthma, lung infiltrates, pericarditis, cardiomyopathy, polyneuropathy, biopsy with inflammatory eosinophilic infiltrates, palpable purpura, digital ischaemia and ANCA positivity, usually anti-myeloperoxidase, among others, were identified.

CONCLUSION

The identification of a comprehensive set of red flags could be used to raise a suspicion of EGPA in patients with eosinophilia, providing clinicians with an evidence-based checklist tool that can be integrated into their practice.

Acute Liver Injury and Bilateral Pulmonary Artery Thrombosis Due to Hypereosinophilic Syndrome

A 46-year-old Japanese man was referred to our hospital because of a marked increase in his eosinophil count (22,870/μL) and elevated liver enzyme levels. Computed tomography (CT) showed thrombi measuring approximately 8 cm in both femoral veins. A liver biopsy revealed eosinophilic infiltration, hepatocyte necrosis, fibrosis, and multiple thrombi. We suspected acute liver injury and deep vein thrombosis associated with hypereosinophilic syndrome and initiated steroids and heparin treatment. Four days after starting treatment, the patient experienced sudden chest pain and cardiopulmonary arrest. CT revealed bilateral pulmonary artery thrombosis, and despite administration of a tissue plasminogen activator, the patient died.

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

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

Myeloproliferative neoplasm with eosinophilia and coexisting BCR::ABL1 and PDGFRB rearrangement: favorable and rapid response to imatinib

Here, we present a rare case of myeloproliferative neoplasms (MPN) with eosinophilia harboring both BCR::ABL1 and PDGFRB rearrangements, posing a classification dilemma. The patient exhibited clinical and laboratory features suggestive of chronic myeloid leukemia (CML) and myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions (MLN-TK), highlighting the diagnostic challenges associated with overlapping phenotypes. Despite the complexity, imatinib treatment swiftly achieved deep molecular remission, underscoring the therapeutic efficacy of tyrosine kinase inhibitors in such scenarios. Furthermore, the rapid attainment of deep remission by this patient in response to imatinib closely resembles that observed in MLN-TK patients with PDGFRB rearrangements. Further research is warranted to elucidate the underlying mechanisms driving the coexistence of multiple oncogenic rearrangements in MPNs and to optimize therapeutic strategies for these complex cases.

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

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

Atypical chronic myeloid leukemia found in a patient with eosinophilia for six years: a case report

BACKGROUND

Atypical chronic myeloid leukemia (aCML) is a highly aggressive type of blood cancer that falls under the category of myelodysplastic/myeloproliferative neoplasms (MDS/MPN). In the fifth edition of the WHO classification of tumors, this category has been renamed MDS/MPN with neutrophilia. Although eosinophilia is commonly observed in blood cancers, it is rarely seen in aCML.

CASE PRESENTATION

This study presents a case of aCML that was diagnosed six years after the patient developed eosinophilia. The patient had undergone tests to rule out other primary and secondary diseases, but the eosinophilia remained unexplained. Treatment with corticosteroids and hydroxyurea had proven ineffective. Six years later, the patient experienced an increase in white blood cells, primarily neutrophils. After ruling out other possible diagnoses, a combination of morphologic and molecular genetic findings led to the diagnosis of aCML. The patient responded well to treatment with azacitidine.

CONCLUSIONS

This study summarizes the current state of aCML diagnosis and management and discusses the possible connection between eosinophilia and aCML.

Blood and local eosinophil levels in chronic rhinitis: Observations during seasonal allergen exposure and non-exposure

Background

Allergic rhinitis (AR) is a typical type 2 inflammatory disease and eosinophils play a critical role of cardinal effectors in type 2 inflammation. However, the distribution of eosinophils in patients with different subtypes of rhinitis and the effect of allergen exposure on them remain understudied. The aim of this study was to investigate the characteristics and factors influencing the distribution of systemic and local eosinophils in patients with non-AR (NAR), perennial AR (PAR), and seasonal AR (SAR), as well as the effect of seasonal allergen exposure levels on eosinophils.

Methods

This was a population-based, cross-sectional observational study of consecutive chronic rhinitis (CR) outpatients who volunteered to participate in the survey during the spring pollen season and non-pollen season of 2023 in Beijing. All participants underwent serum allergen testing, blood routine examination, and nasal secretion smear cytology, and completed questionnaires mainly involving basic information, history review, and symptom assessment. Spring pollen dispersal concentration were considered.

Results

A total of 558 CR patients eligible for enrollment were collected, including 198 NAR, 204 PAR, and 156 SAR patients. PAR had the highest blood eosinophil levels and the most severe overall nasal and ocular symptoms of SAR. Compared with subjects with blood eosinophil counts <0.3 × 109/L, those with ≥0.3 × 109/L had significantly more severe nasal and ocular symptoms and a significantly higher rate of comorbid asthma and allergic conjunctivitis. Blood eosinophil levels were significantly higher in SAR patients during the pollen season compared to the non-pollen season, and pollen concentrations were positively correlated with systemic and local eosinophil levels.

Conclusions

Blood eosinophil levels varied in patients with different subtypes of rhinitis. Patients with high blood eosinophil levels had more severe overall nasal and ocular symptoms, and that blood eosinophils levels were significantly higher in patients with asthma or allergic conjunctivitis than patients without comorbidities. There was a positive trend between allergen exposure and systemic and local eosinophil levels. Further longitudinal cohort studies are still needed to better analyze the influence of eosinophil levels on the clinical traits of AR.

An Unusual Case of Immune Complex-Mediated Membranoproliferative Glomerulonephritis as Renal Manifestation of Idiopathic Hypereosinophilic Syndrome: A Case Report and Literature Review

BACKGROUND

Idiopathic hypereosinophilic syndrome (IHES) is a disorder characterized by abnormal and persistent peripheral blood hypereosinophilia (eosinophil count ≥ 1.5 × 109/L and ≥10% eosinophils) with duration ≥ 6 months, associated organ damage, and/or dysfunction attributable to tissue eosinophilic infiltrate of unknown cause. IHES affects different organs such as the heart, lungs, nervous system, and skin, with renal involvement being rare in this condition.

CASE PRESENTATION

We present a case of a young patient with IHES and immune complex-mediated membranoproliferative glomerulonephritis with nephrotic syndrome, as a rare renal manifestation. We discuss the clinical, analytical, and histopathologic renal and hematologic features, comparing them with other reported cases in the literature.

Hypereosinophilia and Left Ventricular Thrombus: A Case Report and Literature Review

Left ventricular thrombus (LVT) has historically been reported as a complication of acute left ventricular (LV) myocardial infarction. It is most commonly observed in cases of LV systolic dysfunction attributed to ischemic or nonischemic etiologies. Conversely, the occurrence of LVT in normal LV systolic function is an exceptionally rare presentation and is predominantly associated with conditions such as hypereosinophilic syndrome (HES), cardiac amyloidosis, left ventricular noncompaction, hypertrophic cardiomyopathy (HCM), hypercoagulability states, immune-mediated disorders, and malignancies. Notably, hypereosinophilia (HE) has been linked with thrombotic events. Intracardiac thrombus is a well-known complication of eosinophilic myocarditis (EM) or Loeffler endomyocarditis, both of which are considered clinical manifestations of HES. We present a case of a 63-year-old male with normal LV systolic function, HE, and noncontributory hypercoagulability workup, who presented with thromboembolic complications arising from LVT. Interestingly, the diagnostic evaluation for EM and Loeffler endocarditis was nonconfirmatory. Additionally, we performed a literature review to delineate all similar cases. This article also outlines the pathophysiology, diagnosis, and treatment approaches for hypereosinophilic cardiac involvement with a specific focus on LVT.

All-cause mortality and related factors in patients with varying degrees of peripheral blood eosinophilia

The aim of this study was to investigate all-cause mortality rates and related factors in patients with different levels of eosinophilia. This retrospective cohort study was conducted between January 2020 and December 2022 in the Internal Medicine Department of Dr Sadi Konuk Training and Research Hospital, Istanbul, Turkiye. A total of 161 patients with eosinophilia (at least 3 times) were included and divided into groups with absolute eosinophil counts of 500-999/µL (mild), 1000-1500/µL (moderate), and >1500/µL (severe). The mean age of patients was 65.67 ± 16.64 years at the time of admission, and 45 patients (57.8%) were male. The rates of mortality, oncological disease, and organ involvement were significantly higher in the severe group (P < .05). Increased serum total immunoglobulin E and vitamin B12, hematocrit value, eosinophil-to-lymphocyte ratio, and leukocyte were observed in eosinophilic patients. Decreased lymphocyte count, hemoglobin and hematocrit values were higher in deceased patients than in survivors (P < .05). Increased eosinophil-to-lymphocyte ratio, C-reactive protein, vitamin B12, and lactate dehydrogenase (LDH) activity were observed in participants who died compared to those who survived (P < .05). Multivariable logistic regression revealed that advanced age and higher LDH activity were independently associated with greater mortality risk while receiving non-steroid anti-inflammatory drugs or proton-pump inhibitors were associated with reduced mortality risk (P < .05). Advanced age and increased LDH activity were independently associated with greater risk for mortality, whereas absolute eosinophil counts was not. Considering the literature on this topic, our results show the need for further clinical and fundamental research to understand the role of eosinophils in human disease.

Severe hypereosinophilia in a patient treated with dupilumab and shift to mepolizumab: the importance of multidisciplinary management. A case report and literature review

Type 2 inflammation is a heterogeneous condition due to the complex activation of different immunological pathways. Rapid progress in research to evaluate the efficacy of biologics for chronic rhinosinusitis with nasal polyps and asthma has led to the availability of effective therapeutic options. These drugs are safe, but temporary iatrogenic hypereosinophilia may sometimes be associated with clinical symptoms or organ damage. Here, we describe a case of severe hypereosinophilia in a patient with chronic rhinosinusitis with nasal polyps and asthma treated with dupilumab and a subsequent therapeutic shift to mepolizumab that led to maintenance of symptom control and concomitant normalization of blood eosinophil count.

[Eosinophils in otorhinolaryngology: friend or foe?]

This article summarizes the essential aspects of current knowledge about eosinophils, classifies eosinophilia in terms of the dimensions healthy or harmful reaction, takes a specific look at eosinophils in the field of otorhinolaryngology, and gives recommendations for diagnostic workup and therapeutic intervention in case of proven eosinophilia, particularly as an adverse drug reaction. The thoughts are inspired by communications at the 29th Congress of the European Rhinologic Society in Sofia, Bulgaria, 2023.

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

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

Post-marketing safety of anti-IL-5 monoclonal antibodies (mAbs): an analysis of the FDA Adverse Event Reporting System (FAERS)

BACKGROUND

Anti-IL-5 monoclonal antibodies (mAbs) targeting IL-5 or IL-5 R α (including mepolizumab, benralizumab, and reslizumab) are widely used for inflammatory diseases such as asthma, eosinophilia, and polyangiitis. However, real-world data regarding its safety in a large sample population are incomplete. So, we evaluated the safety of anti-IL-5 mAbs by pharmacovigilance analyzes based on related adverse events (AEs) from the FDA Adverse Event Reporting System (FAERS).

METHODS

In disproportionality analysis, four algorithms were employed to detect the signals of anti-IL-5 mAbs from the FAERS between 2016 and 2022. In addition, we also used MYSQL 8.0, Navicat Premium 15, and Microsoft EXCEL 2019 to analyze the signals of anti-IL-5 mAbs systematically.

RESULTS

There are 9,476,351 reports collected from the FAERS database, of which 22,174 reports listed anti-IL-5 mAbs as the 'primary suspected (PS)' drug. A total of 59 (20 new signals, mepolizumab) and 62 (19 new signals, benralizumab) significant disproportionality preferred terms (PTs) conforming to the four algorithms were retained synchronously. Finally, we detected that the anti-IL-5 mAbs-induced AEs occurred in 31 organ systems (mepolizumab) and 30 organ systems (benralizumab). For mepolizumab and reslizumab, unexpected and new significant PTs of AEs were found, such as asthmatic crisis, chronic obstructive pulmonary disease (COPD), pneumonia, COVID-19, pneumothorax, adrenal insufficiency and so on. Notably, the risk signal of asthmatic crisis for mepolizumab was stronger than benralizumab (ROR 108.04 [95%CI, 96.09-121.47] vs 26.83 [95%CI, 18.91-38.06]). Comparing with mepolizumab and benralizumab, we found the proportion of serious adverse events in mepolizumab was both greater than benralizumab in each age group (≤20, 20-65, and ≥ 65). The median onset time of mepolizumab was 280 days (interquartile range [IQR] 1-367 days).

CONCLUSION

Analysis of FAERS data identified anti-IL-5 mAbs-associated AEs, and our findings supported continuous clinical monitoring, pharmacovigilance, and further studies of anti-IL-5 mAbs. In addition, clinicians may be more aware of the limitations of use in package inserts of anti-IL-5 mAbs: Not for relief of acute bronchospasm or status asthmaticus. Because of some limitations in the FAERS such as self-reports from patients and other confounding factors, the safety of anti-IL-5 mAbs needed more studies in different dimensions, especially the risk of cancer.

Approach to Acute Myeloid Leukemia with Increased Eosinophils and Basophils

There is remarkable morphologic and genetic heterogeneity in acute myeloid leukemia (AML). In a small percentage of cases of AML, increased eosinophils and/or basophils are present in the bone marrow and sometimes in the peripheral blood. This is often a puzzling diagnostic situation but also an important finding that requires special investigation. Unique chromosomal rearrangements have been correlated with an increased number of eosinophils and basophils in AML. The identification of the underlying genetic lesion that promotes eosinophilia and basophilia can dramatically change both the prognosis and the treatment of the patient. Thus, clinicians must be vigilant in searching for the cause of eosinophilia and basophilia in patients with AML, since the different causes may lead to different treatments and survival outcomes. In this article, we examine the significance of increased eosinophils and/or basophils in the context of AML, provide guidance that simplifies the differential diagnosis, and give prognostic and therapeutic information about specific subtypes of AML associated with eosinophilia and/or basophilia. Evidence supporting personalized (molecularly targeted) therapy for these patients is also presented.

Pseudo-Meigs' Syndrome With Eosinophilic Pleural Effusion

We present a rare case of a 45-year-old woman with pseudo-Meigs' syndrome and eosinophilic pleural effusion (EPE). She experienced cough, sputum, and dyspnea with a large right pleural effusion. Laboratory tests showed eosinophilia in the blood and pleural fluid. An ovarian tumor and ascites were also detected. After left salpingo-oophorectomy, the tumor was diagnosed as a mature cystic teratoma of the left ovary. The right-sided pleural effusion gradually resolved. Pseudo-Meigs' syndrome is characterized by benign ovarian tumor, ascites, and pleural effusion. Typically, it is associated with exudate pleural effusion characterized by a predominance of mononuclear cells. The occurrence of eosinophilic pleural effusion in our patient may be exceptionally rare.

Eosinophilic Patterns in Patients with Seasonal Allergy Affected by Bronchial Asthma and Rhinitis/Rhinosinusitis: Efficacy of Benralizumab in Patients with the Persistent Pattern

BACKGROUND

Eosinophilia can be influenced by multiple factors. This study aims to set a protocol for monitoring blood absolute eosinophil count (AEC) in patients with seasonal allergy affected by bronchial asthma (BA), allergic rhinitis (AR), or chronic rhinosinusitis with or without nasal polyposis (CRSw/sNP).

METHODS

We planned a total of four annual blood samples to measure AEC in- and out-seasonal pollen exposure (i.e., one measurement every three months for one year).

RESULTS

We identified two distinct groups of patients (non-eosinophilic and eosinophilic). Patients in the eosinophilic group presented with four different patterns (episodic, transient, floating, and persistent). Most patients with episodic, transient, and floating patterns were affected by mild allergy and the increase in eosinophils was related to allergen exposure. In contrast, patients with the persistent pattern mostly presented with more severe allergy (i.e., severe BA and relapsing CRSwNP) and the eosinophilia was unrelated to allergen exposure. The subgroup of patients with severe BA, relapsing CRSwNP, and persistent eosinophilc pattern were treated with benralizumab, which induced a noteworthy improvement in both severe BA and CRSwNP.

CONCLUSIONS

Multiple AEC measurements in patients with seasonal allergy can better reflect patient's eosinophilic status and help define the relationship of AEC enhancement with allergen exposure.

Case report: Rare benign obstructive disease of the biliary tract-a rare case of eosinophilic cholangitis

Objective

Eosinophilic cholangitis (EC) is an uncommon form of benign biliary obstruction. It frequently eludes accurate clinical diagnosis, leading to inappropriate treatment methods. It is our aspiration that this clinical report will impart comprehensive insights into EC and, specifically, the critical role of tomographic examination.

Case summary

A 34-year-old man was urgently admitted to the hospital due to excruciating abdominal distress persisting for several hours. Following a six-day course of anti-inflammatory therapy, his symptoms displayed marginal improvement, prompting his discharge. He returned to the hospital a month later for re-examination on doctor's orders. Based on the results of the re-examination, the patient refused steroid hormone shock therapy and subsequently underwent laparoscopic left-lateral hepatic lobectomy in order to confirm the diagnosis. The preoperative absolute counts of eosinophils in the peripheral blood were documented as 2.3 × 109/L, 3.06 × 109/L, and 1.50 × 109/L consecutively; concurrently, the corresponding percentages of eosinophils were quantified at levels of 21.90%, 30.70%, and 19.20%. The subsequent postoperative pathological assessment unveiled EC as the definitive diagnosis. The patient has since remained free from disease recurrence and is presently alive.

Conclusion

When encountering a patient presenting with persistent elevation in absolute eosinophil count in peripheral blood, coupled with imaging manifestations suggestive of intrahepatic periductal inflammation, diagnosis of EC should be highly suspected. The most optimal diagnostic and therapeutic workflow for EC could entail CT-guided liver lesion biopsy, ensued by glucocorticoid pulse therapy, and finally, short-term monitoring utilizing CT or MRI (including T1WI, T2WI, DWI, CEMRI) techniques.

[Guideline of the diagnosis and treatment of eosinophilic disorders (2024)]

The eosinophilias encompass a broad range of nonhematologic (secondary or reactive) and hematologic (primary or clonal) disorders with potential for end-organ damage. Based on new clinical data and increased understanding of disease molecular genetics, the World Health Organization (WHO) and the international consensus classification (ICC) has provided updated criteria and classifications for eosinophilic disorders in 2022. This guideline represents an update of Chinese expert consensus on the diagnosis and treatment of eosinophilia published in 2017 and aim to provide Chinese hematologist with clear guidance on management for eosinophilic disorders.

Hematological Neoplasms with Eosinophilia

Eosinophils in peripheral blood account for 0.3-5% of leukocytes, which is equivalent to 0.05-0.5 × 109/L. A count above 0.5 × 109/L is considered to indicate eosinophilia, while a count equal to or above 1.5 × 109/L is defined as hypereosinophilia. In bone marrow aspirate, eosinophilia is considered when eosinophils make up more than 6% of the total nuclear cells. In daily clinical practice, the most common causes of reactive eosinophilia are non-hematologic, whether they are non-neoplastic (allergic diseases, drugs, infections, or immunological diseases) or neoplastic (solid tumors). Eosinophilia that is associated with a hematological malignancy may be reactive or secondary to the production of eosinophilopoietic cytokines, and this is mainly seen in lymphoid neoplasms (Hodgkin lymphoma, mature T-cell neoplasms, lymphocytic variant of hypereosinophilic syndrome, and B-acute lymphoblastic leukemia/lymphoma). Eosinophilia that is associated with a hematological malignancy may also be neoplastic or primary, derived from the malignant clone, usually in myeloid neoplasms or with its origin in stem cells (myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions, acute myeloid leukemia with core binding factor translocations, mastocytosis, myeloproliferative neoplasms, myelodysplastic/myeloproliferative neoplasms, and myelodysplastic neoplasms). There are no concrete data in standardized cytological and cytometric procedures that could predict whether eosinophilia is reactive or clonal. The verification is usually indirect, based on the categorization of the accompanying hematologic malignancy. This review focuses on the broad differential diagnosis of hematological malignancies with eosinophilia.

Expert consensus on the use of systemic glucocorticoids for managing eosinophil-related diseases

Eosinophil-related diseases represent a group of pathologic conditions with highly heterogeneous clinical presentation and symptoms ranging from mild to critical. Both systemic and localized forms of disease are typically treated with glucocorticoids. The approval of novel biologic therapies targeting the interleukin-5 pathway can help reduce the use of systemic glucocorticoids (SGC) in eosinophilic diseases and reduce the risk of SGC-related adverse effects (AEs). In this article, a panel of experts from different medical specialties reviewed current evidence on the use of SGC in two systemic eosinophilic diseases: Eosinophilic Granulomatosis with PolyAngiitis (EGPA) and HyperEosinophilic Syndrome (HES); and in two single-organ (respiratory) eosinophilic diseases: Chronic RhinoSinusitis with Nasal Polyps (CRSwNP) and Severe Asthma with Eosinophil Phenotype (SA-EP), and contrasted it with their experience in clinical practice. Using nominal group technique, they reached consensus on key aspects related to the dose and tapering of SGC as well as on the initiation of biologics as SGC-sparing agents. Early treatment with biologics could help prevent AEs associated with medium and long-term use of SGC.

Retrospective Analysis of 397 Dermatoses Inpatients Associated with Blood Eosinophilia

Background

Blood eosinophilia is often associated with various dermatoses, such as atopic eczema, urticaria, drug eruption, bullous pemphigoid, and hypereosinophilic syndrome (HES). Differential diagnosis is very challenging due to the similarities of clinical and pathological characteristics.

Purpose

To investigate and analyze the clinical characteristics of dermatoses associated with blood eosinophilia (DABE) to further optimize disease management.

Patients and Methods

We conducted a retrospective analysis on 397 DABE patients with blood absolute eosinophil count (AEC) greater than or equal to 0.5×109/L. Clinical characteristics, laboratory values, treatment course, and associated diagnoses were evaluated. All DABE patients were grouped based on the severity of eosinophilia as mild group (0.5 ≤ AEC×109/L < 1.5), moderate group (1.5 ≤ AEC×109/L < 3), and severe group (AEC×109/L ≥ 3).

Results

Our study revealed three distinct patterns: (1) Mild eosinophilia associated with localized skin lesions, atopic history, mildly elevated total serum IgE level, diagnosed with eczema/dermatitis, and frequent antihistamines use. (2) Moderate eosinophilia has the characteristics of both mild group and severe group. (3) The severe eosinophilia group had a high proportion of elderly people without atopic history, but with acute onset, generalized skin lesions, and high level of lactate dehydrogenase, and the majority of them were diagnosed with systemic diseases (HES or tumor).

Conclusion

We summarize the clinical rules of dermatoses associated with blood eosinophilia, hoping to facilitate the diagnosis and treatment for patients.

Myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase fusion genes: A workshop report with focus on novel entities and a literature review including paediatric cases

Myeloid/lymphoid neoplasms with eosinophilia (M/LN-eo) and tyrosine kinase (TK) gene fusions are a rare group of haematopoietic neoplasms with a broad range of clinical and morphological presentations. Paediatric cases have increasingly been recognised. Importantly, not all appear as a chronic myeloid neoplasm and eosinophilia is not always present. In addition, standard cytogenetic and molecular methods may not be sufficient to diagnose M/LN-eo due to cytogenetically cryptic aberrations. Therefore, additional evaluation with fluorescence in-situ hybridisation and other molecular genetic techniques (array-based comparative genomic hybridisation, RNA sequencing) are recommended for the identification of specific TK gene fusions. M/LN-eo with JAK2 and FLT3-rearrangements and ETV6::ABL1 fusion were recently added as a formal member to this category in the International Consensus Classification (ICC) and the 5th edition of the WHO classification (WHO-HAEM5). In addition, other less common defined genetic alterations involving TK genes have been described. This study is an update on M/LN-eo with TK gene fusions with focus on novel entities, as illustrated by cases submitted to the Bone Marrow Workshop, organised by the European Bone Marrow Working Group (EBMWG) within the frame of the 21st European Association for Haematopathology congress (EAHP-SH) in Florence 2022. A literature review was performed including paediatric cases of M/LN-eo with TK gene fusions.

Functional activity of blood eosinophils in patients with <i>Opisthorchis felineus</i> invasion

Aim. To study the functional activity of blood eosinophils in patients with Opisthorchis felineus (O. felineus) invasion.

Material and methods. A total of 328 patients with O. felineus invasion (120 men and 208 women, mean age 40.3 years) and 34 practically healthy patients (14 men and 20 women, mean age 41.1 years) aged 18 to 70 years were examined. The main method for diagnosing opisthorchiasis was the determination of eggs or bodies of adult parasites in the duodenal contents and/or feces, which was used in all 328 patients with opisthorchiasis. All patients underwent a complete blood count and biochemical blood test, esophagogastroduodenoscopy and ultrasound examination of the abdominal organs. The study of the functional activity of blood eosinophils was carried out in 42 patients with opisthorchiasis and 34 healthy individuals from the control group by chemiluminescent analysis with the measurement of the intensity of production of reactive oxygen species in spontaneous and zymosan-induced reactions in lucigenin- and luminol-dependent processes.

Results. The frequency of eosinophils in the complete blood count above 5% in the examined patients with opisthorchiasis was 19.5%. An increase in the content of eosinophils in the blood in patients with opisthorchiasis was associated with an increase in the frequency of complaints of pain in the right hypochondrium, pruritus, skin rashes, an increase in the proportion of leukopenia and neutropenia, an increase in the level of gamma-glutamyl transpeptidase in the blood, and an increase in the frequency of ultrasound signs of cholecystitis. At the same time, a pronounced increase in the functional activity of blood eosinophils, determined by the chemiluminescent method, was observed in patients with O. felineus invasion.

Conclusions. Patients with O. felineus invasion with an increase in the content of eosinophils in the blood due to the likelihood of an aggressive course of the pathology deserve the close attention of practitioners with the need for a thorough comprehensive examination of patients, including immunological methods.

Acute myeloid leukemia with LRRFIP1::FGFR1 rearrangement and a complex karyotype

We report a case of a 20-year-old man who presented with splenomegaly, hyperleukocytosis, anemia, and thrombocytopenia. A diagnosis of acute myeloid leukemia (AML) with LRRFIP1::FGFR1 rearrangement with complex karyotype was determined. Chromosome analysis showed a male karyotype: 46,XY,i(1)(q10),t(2;8)(q37;p11.2),der(5)t(1;5) (p22;q13)[17]46,XY[3]. Fluorescence in situ hybridization (FISH) analysis using the Cytocell FGFR1 break apart/amplification probe detected FGFR1 rearrangement with t(2:8) in 126/200 cells analyzed. Other FISH probes including 1p36/ 1q25 probes, del(5q) deletion probe, TLX3 break apart probe, and PDGFRB break apart probe were also utilized to confirm the other karyotypic abnormalities. Next-generation sequencing (NGS) SureSelectXT Custom DNA Target Somatic Detection detected RUNX1 gene mutation. NGS Archer FusionPlex (RNA) confirmed the LRRFIP1::FGFR1 rearrangement. This is the second reported case of AML with LRRFIP1::FGFR1 rearrangement and the first with a complex karyotype.

Lymphomatoid papulosis associated with myeloid neoplasm with eosinophilia and FIP1L1::PDGFRA rearrangement: Successful imatinib treatment in two cases

Lymphomatoid papulosis (LyP) is a benign condition, listed among primary cutaneous CD30+ lymphoproliferative disorders. Its typical picture consists of relapsing-remitting papular lesions and it can be encountered in the course of a hematologic disease, at times representing its first manifestation. Hypereosinophilic syndromes are a heterogeneous group of disorders characterized by persistent peripheral blood hypereosinophilia that may lead to life-threatening organ damage. Among eosinophilic disorders, the subtype identified as myeloid/lymphoid neoplasm with eosinophilia and tyrosine kinase gene fusions has aroused particular interest due to its excellent response to tyrosine kinase inhibitors, including imatinib. Here, we described the case of two 33-year-old men presenting with LyP and myeloid neoplasm with eosinophilia and FIP1L1::PDGFRA rearrangement who achieved complete clinical and molecular remission of both conditions a few months after starting imatinib.

A Rare Presentation of Hypereosinophilic Syndrome With Loffler's Endomyocarditis, Encephalopathy, and Multiple Thromboembolic Strokes

Idiopathic hypereosinophilic syndrome is a disorder with a high eosinophilic count for which no identifiable cause is evident. Herein we report a case of a 47-year-old male with a background history of hypereosinophilia, who presented with sudden onset altered level of consciousness and drowsiness for 1-day duration associated with a gradual onset progressive memory loss for 1-month duration. Based on clinical, biochemical, and imaging studies, a diagnosis of Loffler's endomyocarditis was made for which he was treated with albendazole with diethylcarbamazine along with high-dose steroids. He made a successful recovery after 2 months of treatment.

FIP1L1-PDGFRA Clonal Hypereosinophilic Syndrome With Eosinophilic Myocarditis and Intracardiac Thrombus

A 45-year-old man from El Salvador with no past medical history presented with cough and chest pain. Investigations revealed 60% peripheral eosinophilia (absolute count 12.3 K/uL). Cardiac imaging was consistent with myocarditis with intracardiac thrombus formation. Endomyocardial biopsy confirmed eosinophilic infiltration of the myocardium, and bone marrow biopsy showed hypercellular marrow with 28% eosinophils. Cytogenetics/fluorescence in situ hybridization (FISH) confirmed positive FIP1L1-PDGFRA rearrangement. The patient was treated for FIP1L1-PDGFRA clonal hypereosinophilic syndrome with associated eosinophilic myocarditis and intracardiac thrombus. The treatment regimen consisted of a steroid taper, imatinib, and anticoagulation. Treatment was followed by normalization of the eosinophil count. At two-year follow-up, the patient was without recurrence of eosinophilia on maintenance imatinib and indefinite anticoagulation with warfarin.

Case Report: Off-label treatment of idiopathic hypereosinophilic syndrome with Omalizumab

Idiopathic hypereosinophilic syndrome (IHES) is a rare disease characterized by causeless persistent hypereosinophilia and eosinophilia-associated end-organ damage. Current treatment modalities don't meet the needs due to adverse events of steroids as first-line therapy and the limited efficacy of second-line treatments, underscoring the need for new therapeutic strategies. Here we presented two cases of IHES with different clinical manifestations that were both refractory to corticosteroids. Patient #1 experienced rashes, cough, pneumonia, and steroid-induced side effects. Patient #2 had severe gastrointestinal symptoms attributed to hypereosinophilia. They both had high levels of serum IgE, didn't respond well to second-line treatments of interferon-α (IFN-α) and imatinib, and Mepolizumab was not accessible. We then innovatively switched to Omalizumab, an anti-IgE monoclonal antibody approved for allergic asthma and chronic idiopathic urticaria. Patient #1 was treated with Omalizumab 600 mg per month for 20 months; his absolute eosinophil count (AEC) decreased significantly and has stabilized at around 1.0×10⁹/L for 17 months, with complete relief from erythra and cough. Patient #2 recovered promptly from severe diarrhea with a sharp drop in AEC after 3 months of treatment with omalizumab at 600 mg per month. Therefore, we concluded that Omalizumab may be a seminal therapeutic strategy for IHES patients who are refractory to corticosteroids, whether as long-term management of AEC or as an urgent intervention to address severe symptoms caused by eosinophilia.

Idiopathic Hypereosinophilic Syndrome: A Case Report

Idiopathic hypereosinophilic syndrome is a rare condition characterized by persistent severe eosinophilia and organ damage without any apparent cause. A 20-year-old male patient with no significant medical history was admitted to the Emergency Department with retrosternal chest pain, fatigue and asthenia. EKG showed ST elevation I, II, III, aVF, V4-V6 and blood tests showed elevated troponin levels. An echocardiogram was performed revealing severe global left ventricular systolic dysfunction. Further evaluations included cardiac magnetic resonance imaging and endomyocardial biopsy, confirming the diagnosis of eosinophilic myocarditis. The patient was started on systemic corticosteroid therapy, resulting in clinical improvement. The patient was discharged after 12 days of hospitalization, following a recovery of biventricular function and he was told to continue oral corticosteroid therapy at home. Further investigation ruled out other causes of hypereosinophilic syndromes, therefore the diagnosis of idiopathic hypereosinophilic syndrome was assumed. Despite the attempt to reduce corticosteroid therapy, the eosinophil count became elevated again, so the dosage was increased and associated with azathioprine with subsequent favorable analytical evolution. This case highlights the challenges in diagnosing and managing idiopathic hypereosinophilic syndrome and emphasizes the importance of prompt treatment initiation to prevent complications.