Hypereosinophilic Syndrome

From Gut Microbiomes to Infectious Pathogens: Neurological Disease Game Changers

Gut microbiota and infectious diseases affect neurological disorders, brain development, and function. Compounds generated in the gastrointestinal system by gut microbiota and infectious pathogens may mediate gut-brain interactions, which may circulate throughout the body and spread to numerous organs, including the brain. Studies shown that gut bacteria and disease-causing organisms may pass molecular signals to the brain, affecting neurological function, neurodevelopment, and neurodegenerative diseases. This article discusses microorganism-producing metabolites with neuromodulator activity, signaling routes from microbial flora to the brain, and the potential direct effects of gut bacteria and infectious pathogens on brain cells. The review also considered the neurological aspects of infectious diseases. The infectious diseases affecting neurological functions and the disease modifications have been discussed thoroughly. Recent discoveries and unique insights in this perspective need further validation. Research on the complex molecular interactions between gut bacteria, infectious pathogens, and the CNS provides valuable insights into the pathogenesis of neurodegenerative, behavioral, and psychiatric illnesses. This study may provide insights into advanced drug discovery processes for neurological disorders by considering the influence of microbial communities inside the human body.

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.

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms. Part II diagnosis and management

Drug-induced hypersensitivity syndrome, also known as drug reaction with eosinophilia and systemic symptoms, is a severe cutaneous adverse reaction characterized by an exanthem, fever, and hematologic and visceral organ involvement. The differential diagnosis includes other cutaneous adverse reactions, infections, inflammatory and autoimmune diseases, and neoplastic disorders. Three sets of diagnostic criteria have been proposed; however, consensus is lacking. The cornerstone of management is immediate discontinuation of the suspected drug culprit. Systemic corticosteroids remain first-line therapy, but the literature on steroid-sparing agents is expanding. Longitudinal evaluation for sequelae is recommended. Adjunctive tests for risk stratification and drug culprit identification remain under investigation. Part II of this continuing medical education activity begins by exploring the differential diagnosis and diagnosis of drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms and concludes with an evidence-based overview of evaluation and treatment.

[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.

Cardiac Magnetic Resonance Imaging Used to Determine a Rare Etiology of a Layered Left Ventricular Apical Thrombus

Eosinophilic myocarditis (EM) is a rare disease, often associated with hypereosinophilic syndrome (HES). Historically, the diagnostic gold standard was endomyocardial biopsy (EMB). We present a unique case of a 58-year-old female who presents after a syncopal episode and was found to have a layered left ventricular (LV) thrombus. Using laboratory studies and cardiac magnetic resonance imaging (MRI), we were able to delineate the etiology, avoiding any invasive testing.

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

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

Human germline gain-of-function in STAT6: from severe allergic disease to lymphoma and beyond

Signal transducer and activator of transcription (STAT)-6 is a transcription factor central to pro-allergic immune responses, although the function of human STAT6 at the whole-organism level has long remained unknown. Germline heterozygous gain-of-function (GOF) rare variants in STAT6 have been recently recognized to cause a broad and severe clinical phenotype of early-onset, multi-system allergic disease. Here, we provide an overview of the clinical presentation of STAT6-GOF disease, discussing how dysregulation of the STAT6 pathway causes severe allergic disease, and identifying possible targeted treatment approaches. Finally, we explore the mechanistic overlap between STAT6-GOF disease and other monogenic atopic disorders, and how this group of inborn errors of immunity (IEIs) powerfully inform our fundamental understanding of common human allergic disease.

B-cell acute lymphoblastic leukemia associated with hypereosinophilia: a case report and brief literature review

Few cases of B-cell acute lymphoblastic leukemia (B-ALL)-eosinophilia (ALL-eo) association have been reported. The lack or absence of blasts in the peripheral blood smear (PBS) along with urticarial rash, fever, arthralgia, myalgia, sweating, and dyspnea are common features of this condition. Herein, we report a 16-year-old male patient admitted to the emergency department with urticaria and generalized itching. PBS was examined, and eosinophils (90%) were seen in different fields. However, blast cells were not seen in PBS. In a bone marrow examination, terminal deoxynucleotidyl transferase-positive and CD20-positive lymphoid blasts were reported along with eosinophilia. Eventually, the B-ALL diagnosis was confirmed for the patient, and he was started on the Berlin-Frankfurt-Münster chemotherapy regimen. The association of B-ALL with hypereosinophilia is a rare condition. We hope this case report and literature review can help clinicians to manage this rare condition properly.

Moderate-High Blood Eosinophilia Is Associated with Increased Hospitalization and Other Asthma Comorbidities

(1) Background: Eosinophilia has traditionally been linked to eosinophilic asthma, for which it is the gold-standard prognostic biomarker. However, the association between eosinophilia and the presence of other diseases and comorbidities is yet unclear. (2) Methods: For this retrospective study, we reviewed the electronic medical records of 49,909 subjects with blood eosinophilia to gather data on the presence of asthma, COPD, sleep apnea, tuberculosis, dyslipidemia, hypertension, and other cardiovascular diseases and severe CRSwNP among these subjects. Demographic features including age, sex, and smoking habits were collected, as well as the number of hospitalizations and emergency department visits. T-tests, ANOVA, Fisher test, and logistic regression models were used. (3) Results: For all age groups studied, eosinophilia was significantly more prevalent among asthmatic subjects than nonasthmatics, especially in patients also presenting CRSwNP, hypertension, and dyslipidemia. The likelihood of developing asthma, COPD, and CRSwNP, and hospitalization, was increased when BEC was above 600 eosinophils/μL. The association between asthma, CRSwNP, and BEC was corroborated by multiple logistic regressions models. (4) Conclusions: We demonstrated the association of having over 600 blood eosinophils/μL with a higher number of hospitalizations and comorbidities (CRSwNP and COPD), which proves that BEC is a highly useful parameter to consider in subjects who present blood eosinophilia.

Toxocarosis in a patient with autism spectrum disorder presenting with severe hypereosinophilia and acute respiratory distress: a case report

A boy with known autism spectrum disorder was transferred to our department due to a rapidly worsening respiratory situation. The patient's history revealed previous treatment with albendazole against a Toxocara infection 2 weeks prior in Poland. Blood analysis showed such severe eosinophilia and markedly elevated levels of IgE that, initially, a hematologic malignancy was suspected. However, diagnostic workup including autoimmune diagnostic, molecular genetic testing, fluorescence in situ hybridization (FISH), bone marrow aspiration, and parasitological testing led to the diagnosis of an insufficiently treated Toxocara infection. Treatment with albendazole and prednisone (six cycles for 4 weeks each) was administered. This treatment regime led to prompt improvement of symptoms and normalization of laboratory findings.

A case of atypical IgG4-related disease presenting hypereosinophilia, polyneuropathy, and liver dysfunction

Ig (immunoglobulin) G4-related disease (Ig4-RD) affects several organs, including salivary glands, lacrimal glands, pancreas, biliary ducts, and retroperitoneum. A 72-year-old woman was examined for hypereosinophilia, high levels of IgG4, polyneuropathy, liver dysfunction, enlargement of lymph nodes and lacrimal glands, and beaded dilation of the bile ducts. We diagnosed Ig4-RD based on biopsies of the lymph nodes, liver, and submandibular gland. The symptoms of the patient improved after glucocorticoid treatment. This was a novel and atypical case of Ig4-RD that was difficult to differentiate from other diseases, including eosinophilic granulomatosis with polyangiitis, idiopathic hypereosinophilic syndrome, and polyneuropathy, organomegaly, endocrinopathy, monoclonal plasma cell disorder, skin changes syndrome. This case report highlights the importance of biopsies in differentiating Ig4-RD.

Neurological Manifestations of Infectious Diseases: Insights From Recent Cases

This narrative review examines the complex connection between infectious diseases and their neurological effects. It provides a detailed analysis of recent instances and insights derived from various pathogens. As we explore the realm of infectious agents, including viruses, bacteria, parasites, and fungi, a thorough and diverse analysis reveals the intricacies of neurological problems. The review begins by examining viral infections, specifically focusing on how viruses invade the neurological system and its subsequent effects. Significant instances from recent widespread disease outbreaks function as instructive benchmarks, highlighting the progressing comprehension of these ever-changing interconnections. The article examines the complex pathophysiology of neurological problems caused by bacterial infections. It presents current cases that illustrate the various ways these complications might manifest and the difficulties faced in their therapeutic management. Parasitic and fungal infections, which are typically overlooked, are being carefully examined to emphasize their distinct role in causing neurological complications. The mentioned cases highlight the importance of being thoroughly aware of these less-explored areas ranging from protozoan parasites to opportunistic fungal infections. In addition to the immediate effects caused by infectious agents, the review investigates autoimmune responses activated by infections. It provides a detailed examination of specific instances that shed light on the complex relationship between viral triggers and future neurological problems. This text elaborates on the intricacy of autoimmune-related neurological issues, highlighting the necessity for a comprehensive approach to diagnosing and treating them. The narrative next redirects its attention to the diagnostic difficulties that arise when interpreting the neurological symptoms of viral disorders. This article provides a thorough examination of existing diagnostic tools, along with an investigation into new technologies that have the potential to improve our capacity to identify and comprehend complex presentations. This debate connects to the following examination of treatment methods, where current cases that showcase successful interventions are carefully examined to extract valuable insights into good clinical management. The discussion focuses on the public health implications of preventive efforts against infectious infections, including their neurological consequences. The story emphasizes the link between infectious diseases and overall societal health, advocating for a proactive strategy to reduce the impact of neurological complications. The abstract concludes by providing a prospective viewpoint, highlighting areas of research that still need to be addressed, and suggesting potential future avenues. This narrative review seeks to provide a comprehensive resource for physicians, researchers, and public health professionals dealing with the complex field of neurological manifestations in infectious diseases. It combines recent examples, synthesizes current information, and offers a holistic perspective.

An algorithm-based approach to ascertain patients with rare diseases in electronic health records using hypereosinophilic syndrome as an example

PURPOSE

Improved hypereosinophilic syndrome (HES) ascertainment in electronic health record (EHR) databases may improve disease understanding and management. An algorithm to ascertain and characterize this rare condition was therefore developed and validated.

METHODS

Using the UK clinical practice research datalink (CPRD)-Aurum database linked to the hospital episode statistics database (Admitted Patient Care data) from Jan 2012 to June 2019, this cross-sectional study ascertained patients with a specific HES code (index). Patients with HES were matched (age, sex and index date) 1:29 with a non-HES cohort. An algorithm was developed by identifying pre-defined variables differing between cohorts; model-fitting using Firth logistic regression and statistical determination of the top-five performing models; and internal validation using Leave-One-Out Cross Validation. Final model sensitivity and specificity were determined at an 80% probability threshold.

RESULTS

The HES and non-HES cohorts included 88 and 2552 patients, respectively; 270 models with four variables each (treatment used for HES, asthma code, white blood cell condition code, and blood eosinophil count [BEC] code) plus age and sex variables were tested. Of the top five models, the sensitivity model performed best (sensitivity, 69% [95% CI: 59%, 79%]; specificity, >99%). The strongest predictors of HES versus non-HES cases (odds >1000 times greater) were an ICD-10 code for white blood cell disorders and a BEC ≥1500 cells/μL in the 24 months pre-index.

CONCLUSIONS

Using a combination of medical codes, prescribed treatments data and laboratory results, the algorithm can help ascertain patients with HES from EHR databases; this approach may be useful for other rare diseases.

GEMA 5.3. Spanish Guideline on the Management of Asthma

The Spanish Guideline on the Management of Asthma, better known by its acronym in Spanish GEMA, has been available for more than 20 years. Twenty-one scientific societies or related groups both from Spain and internationally have participated in the preparation and development of the updated edition of GEMA, which in fact has been currently positioned as the reference guide on asthma in the Spanish language worldwide. Its objective is to prevent and improve the clinical situation of people with asthma by increasing the knowledge of healthcare professionals involved in their care. Its purpose is to convert scientific evidence into simple and easy-to-follow practical recommendations. Therefore, it is not a monograph that brings together all the scientific knowledge about the disease, but rather a brief document with the essentials, designed to be applied quickly in routine clinical practice. The guidelines are necessarily multidisciplinary, developed to be useful and an indispensable tool for physicians of different specialties, as well as nurses and pharmacists. Probably the most outstanding aspects of the guide are the recommendations to: establish the diagnosis of asthma using a sequential algorithm based on objective diagnostic tests; the follow-up of patients, preferably based on the strategy of achieving and maintaining control of the disease; treatment according to the level of severity of asthma, using six steps from least to greatest need of pharmaceutical drugs, and the treatment algorithm for the indication of biologics in patients with severe uncontrolled asthma based on phenotypes. And now, in addition to that, there is a novelty for easy use and follow-up through a computer application based on the chatbot-type conversational artificial intelligence (ia-GEMA).

Highlighting Fibroblasts Activation in Fibrosis: The State-of-The-Art Fibroblast Activation Protein Inhibitor PET Imaging in Cardiovascular Diseases

Fibrosis is a common healing process that occurs during stress and injury in cardiovascular diseases. The evolution of fibrosis is associated with cardiovascular disease states and causes adverse effects. Fibroblast activation is responsible for the formation and progression of fibrosis. The incipient detection of activated fibroblasts is important for patient management and prognosis. Fibroblast activation protein (FAP), a membrane-bound serine protease, is almost specifically expressed in activated fibroblasts. The development of targeted FAP-inhibitor (FAPI) positron emission tomography (PET) imaging enabled the visualisation of FAP, that is, incipient fibrosis. Recently, research on FAPI PET imaging in cardiovascular diseases increased and is highly sought. Hence, we comprehensively reviewed the application of FAPI PET imaging in cardiovascular diseases based on the state-of-the-art published research. These studies provided some insights into the value of FAPI PET imaging in the early detection of cardiovascular fibrosis, risk stratification, response evaluation, and prediction of the evolution of left ventricular function. Future studies should be conducted with larger populations and multicentre patterns, especially for response evaluation and outcome prediction.

Case report: Probable toxocariasis in a Swiss adult patient with hypereosinophilic syndrome and multiorgan involvement

Hypereosinophilic syndromes are a heterogeneous group of rare diseases characterized by eosinophil-related organ damage and peripheral blood hypereosinophilia. Hypereosinophilic syndromes may occur secondary to a variety of clinical entities, for example, drug hypersensitivity reactions, parasitic infections, autoimmune disorders, and malignancies. Toxocariasis is a parasitic infection caused by the larval stage of the Toxocara species. It is usually a childhood disease and invades organs such as the liver but can affect any organ. Hypereosinophilic syndrome and multiorgan involvement are very rare manifestations of Toxocara infection, especially in adults. However, the disease may be underdiagnosed because of different factors, including a lack of laboratory infrastructure in some countries, a lack of uniform case definitions, and limited surveillance infrastructure, with its estimation constituting a challenge. We, therefore, present a probable case of hypereosinophilic syndrome with multiorgan involvement secondary to infection with Toxocara canis in a 79-year-old Swiss female patient with a medical history of ischemic cerebrovascular insult and a curatively resected non-small-cell bronchial carcinoma, successfully treated with albendazole and steroids.

Idiopathic hypereosinophilic syndrome with hepatic sinusoidal obstruction syndrome: A case report and literature review

BACKGROUND

Hypereosinophilic syndrome (HES) is classified as primary, secondary or idiopathic. Idiopathic HES (IHES) has a variable clinical presentation and may involve multiple organs causing severe damage. Hepatic sinusoidal obstruction syndrome (HSOS) is characterized by damage to the endothelial cells of the hepatic sinusoids of the hepatic venules, with occlusion of the hepatic venules, and hepatocyte necrosis. We report a case of IHES with HSOS of uncertain etiology.

CASE SUMMARY

A 70-year-old male patient was admitted to our hospital with pruritus and a rash on the extremities for > 5 mo. He had previously undergone antiallergic treatment and herbal therapy in the local hospital, but the symptoms recurred. Relevant examinations were completed after admission. Bone marrow aspiration biopsy showed a significantly higher percentage of eosinophils (23%) with approximately normal morphology. Ultrasound-guided hepatic aspiration biopsy indicated HSOS. Contrast-enhanced computed tomography (CT) of the upper abdomen showed hepatic venule congestion with hydrothorax and ascites. The patient was initially diagnosed with IHES and hepatic venule occlusion. Prednisone, low molecular weight heparin and ursodeoxycholic acid were given for treatment, followed by discontinuation of low molecular weight heparin due to ecchymosis. Routine blood tests, biochemical tests, and imaging such as enhanced CT of the upper abdomen and pelvis were reviewed regularly.

CONCLUSION

Hypereosinophilia may play a facilitating role in the occurrence and development of HSOS.

HES and EGPA: Two Sides of the Same Coin

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

The multidisciplinary approach to eosinophilia

Eosinophilic granulocytes are normally present in low numbers in the bloodstream. Patients with an increased number of eosinophilic granulocytes in the differential count (eosinophilia) are common and can pose a clinical challenge because conditions with eosinophilia occur in all medical specialties. The diagnostic approach must be guided by a thorough medical history, supported by specific tests to guide individualized treatment. Neoplastic (primary) eosinophilia is identified by one of several unique acquired genetic causes. In contrast, reactive (secondary) eosinophilia is associated with a cytokine stimulus in a specific disease, while idiopathic eosinophilia is a diagnosis by exclusion. Rational treatment is disease-directed in secondary cases and has paved the way for targeted treatment against the driver in primary eosinophilia, whereas idiopathic cases are treated as needed by principles in eosinophilia originating from clonal drivers. The vast majority of patients are diagnosed with secondary eosinophilia and are managed by the relevant specialty-e.g., rheumatology, allergy, dermatology, gastroenterology, pulmonary medicine, hematology, or infectious disease. The overlap in symptoms and the risk of irreversible organ involvement in eosinophilia, irrespective of the cause, warrants that patients without a diagnostic clarification or who do not respond to adequate treatment should be referred to a multidisciplinary function anchored in a hematology department for evaluation. This review presents the pathophysiology, manifestations, differential diagnosis, diagnostic workup, and management of (adult) patients with eosinophilia. The purpose is to place eosinophilia in a clinical context, and therefore justify and inspire the establishment of a multidisciplinary team of experts from diagnostic and clinical specialties at the regional level to support the second opinion. The target patient population requires highly specialized laboratory analysis and therapy and occasionally has severe eosinophil-induced organ dysfunction. An added value of a centralized, clinical function is to serve as a platform for education and research to further improve the management of patients with eosinophilia. Primary and idiopathic eosinophilia are key topics in the review, which also address current research and discusses outstanding issues in the field.

Management of eosinophil-associated inflammatory diseases: the importance of a multidisciplinary approach

Elevated eosinophil counts in blood and tissue are a feature of many pathological processes. Eosinophils can migrate and accumulate in a wide variety of tissues and, by infiltrating a target organ, can mediate the development of several inflammatory diseases. The normalization of eosinophilia is a common biomarker of a treatable trait and can also be used as a prognostic and predictive biomarker since it implies a reduction in type 2 inflammation that contributes to disease pathogenesis. Biological therapies targeting this cell type and its proinflammatory mediators have been shown to be effective in the management of a number of eosinophilic diseases, and for this reason they constitute a potential common strategy in the treatment of patients with various multimorbidities that present with type 2 inflammation. Various biological options are available that could be used to simultaneously treat multiple target organs with a single drug, bearing in mind the need to offer personalized treatments under the umbrella of precision medicine in all patients with eosinophil-associated diseases (EADs). In addition to reviewing these issues, we also discuss a series of perspectives addressing the management of EAD patients from a multidisciplinary approach, with the collaboration of health professionals from different specialties who manage the different multimorbidities that frequently occur in these patients. We examine the basic principles of care that this multidisciplinary approach must cover and present a multidisciplinary expert opinion regarding the ideal management of patients with EADs, from diagnosis to therapeutic approach and follow-up.

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

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

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

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

Hyepereosiniphilic syndrome and COVID-19: 2 case reports

BACKGROUND

Nearly half of the patients with hypereosinophilic syndrome (HES) have cardiovascular involvement, a major cause of mortality. COVID-19 infection can lead to cardiac involvement, negatively impacting the clinical course and prognosis. We reported two patients with HES complicated by COVID-19, with cardiac involvement and valve replacement.

CASE PRESENTATION

Our first patient was a 27-year-old woman admitted due to dyspnea and signs of heart failure. She had severe mitral stenosis and mitral regurgitation on the echocardiogram. Corticosteroid therapy improved her symptoms initially, but she deteriorated following a positive COVID-19 test. A repeated echocardiogram showed right ventricular failure, severe mitral regurgitation, and torrential tricuspid regurgitation and, she underwent mitral and tricuspid valve replacement. Our second patient was a 43-year-old man with HES resulted in severe tricuspid stenosis, which was improved with corticosteroid treatment. He underwent tricuspid valve replacement due to severe valvular regurgitation. He was admitted again following tricuspid prosthetic mechanical valve thrombosis. Initial workups revealed lung involvement in favor of COVID-19 infection, and his PCR test was positive.

CONCLUSION

COVID-19 infection can change the clinical course of HES. It may result in a heart failure exacerbation due to myocardial injury and an increased risk of thrombosis in prosthetic valves or native vessels due to hypercoagulability.

Mepolizumab therapy improves the most bothersome symptoms in patients with hypereosinophilic syndrome

Background

Hypereosinophilic syndrome (HES) is characterized by persistent elevated blood and/or tissue eosinophil levels and eosinophil-mediated organ damage. Presentation is highly heterogenous; patients may experience symptoms affecting multiple organ systems.

Objectives

To assess the effects of mepolizumab, which targets interleukin-5, on HES-related symptom burden, based on HES daily symptoms (HES-DS) questionnaire data collected during the Phase III (ClinicalTrials.gov ID: NCT02836496) study of mepolizumab in patients with HES.

Methods

Each of the six HES-related symptoms were rated (0–10) daily by patients, recalling worst symptom experience in the prior 24 hours; change from baseline at Week 32 was also calculated for mepolizumab versus placebo.

Results

Mepolizumab versus placebo reduced HES-related symptom burden severity in patients with HES at Week 32. Improvements in the median change from baseline scores were seen across all symptom groups except skin for patients treated with mepolizumab; greatest improvement from baseline was observed for breathing symptoms.

Conclusion

These data highlight the considerable symptom burden associated with HES and further support the clinical benefits of mepolizumab treatment for these patients.

Hypereosinophilic Syndrome Following the BNT162b2 (BioNTech/Pfizer) Vaccine Successfully Treated with Mepolizumab: A Case Report and Review of the Literature

Although an increasing number of real-life data confirm large-scale clinical trial findings on the efficacy and safety of SARS-CoV-2 vaccines, rare but severe adverse reactions have begun to emerge. Here, we report a full-blown hypereosinophilic syndrome (HES) following a BNT162b2 (BioNTech/Pfizer) vaccine. A 48-year-old man developed, 5 days after the first shot of the SARS-CoV-2 vaccine, erythematous and painful nodular lesions in the lower and upper limbs accompanied by widespread itching, acrocyanosis with gangrenous lesions at the tips of the first and fourth fingers of the right hand, as well as paresthesia in the right hand and foot. Investigations revealed isolated eosinophilia, occlusion of the right ulnar artery, and electromyography alteration compatible with multifocal sensory neuropathy, as well as minimal accentuation of the interstitial texture with some ground glass appearance. Despite treatment with prednisone in combination with warfarin, he developed thrombosis of the left ulnar artery. Therefore, therapy with an IL-5 inhibitor and acetylsalicylic was successfully added. Given the time interval between the onset of clinical manifestations and the vaccine shot, we believe that the mRNA vaccine triggered the eosinophilic response. This case evidences a possible link between HES and the SARS-CoV-2 vaccination. Mepolizumab, an IL-5 inhibitor, might be considered in steroid refractory cases.

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

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

Recurrent cutaneous eosinophilic vasculitis characterized by annular purpuric lesions: A case report

A 71-year-old woman presented with a persistent, intensely pruritic cutaneous eruption localized on the palmoplantar regions, lips and palate. The histological findings allowed to make the diagnosis of recurrent cutaneous eosinophilic vasculitis, a very rare cutaneous vasculitis characterized clinically by multiple erythematous or purpuric erythematous papules or plaques or angioedema with a relapsing course in the absence of systemic involvement and histologically by a necrotizing vasculitis of the dermal small vessels with a dominant eosinophilic infiltration. The patient was treated with oral methylprednisolone and pentoxifylline which led to a rapid resolution of the cutaneous lesions.

Proposed refined diagnostic criteria and classification of eosinophil disorders and related syndromes

Eosinophilia and eosinophil activation are recurrent features in various reactive states and certain hematologic malignancies. In patients with hypereosinophilia (HE), HE-induced organ damage is often encountered and may lead to the diagnosis of a hypereosinophilic syndrome (HES). A number of known mechanisms and etiologies contribute to the development of HE and HES. Based on these etiologies and the origin of eosinophils, HE and HES are divided into primary forms where eosinophils are clonal cells, reactive forms where an underlying reactive or neoplastic condition is detected and eosinophils are considered to be "non-clonal" cells, and idiopathic HE and HES in which neither a clonal nor a reactive underlying pathology is detected. Since 2012, this classification and the related criteria have been widely accepted and regarded as standard. However, during the past few years, new developments in the field and an increasing number of markers and targets have created a need to update these criteria and the classification of HE and HES. To address this challenge, a Working Conference on eosinophil disorders was organized in 2021. In this conference, a panel of experts representing the relevant fields, including allergy, dermatology, hematology, immunology, laboratory medicine, and pathology, met and discussed new markers and concepts as well as refinements in definitions, criteria and classifications of HE and HES. The outcomes of this conference are presented in this article and should assist in the diagnosis and management of patients with HE and HES in daily practice and in the preparation and conduct of clinical trials.

Insights from Social Media on the Patient Experience of Living With Rare Eosinophil-Driven Diseases

Eosinophilic granulomatosis with polyangiitis (EGPA) and hypereosinophilic syndrome (HES) are driven by persistently high eosinophil numbers, causing damage to tissues and organs. As rare diseases, they are often underappreciated by healthcare professionals. Using a social listening analysis, we collected patient and caregiver comments relating to EGPA and HES made on online social platforms between 1 January 2019 and 31 May 2020, in English, French, and German. Results were classified into key areas of interest. In total, 746 comments with consent to publish were collected mentioning EGPA, and 39 were identified mentioning HES. The most common theme was sharing of personal experiences (EGPA: 77%; HES: 100%). Diagnosis, including diagnosis delays and misdiagnosis, was mentioned in 33% of comments for EGPA, and 82% for HES. Other common themes included seeking and giving advice, symptoms, and treatments. These insights highlight the views and unmet needs of people living with EGPA and HES. Further work should improve disease awareness and effective communications among healthcare professionals and patients with these conditions.

Distinct features of hypereosinophilic syndrome with neuropathy from eosinophilic granulomatosis with polyangiitis

BACKGROUND AND OBJECTIVES

Hypereosinophilic syndrome (HES) and eosinophilic granulomatosis with polyangiitis (EGPA) have overlapping clinical considerations, which frequently involve peripheral neuropathy. The current study aimed to discriminate between the clinicopathological features of HES and EGPA, focusing on the mechanism of peripheral nerve damage.

METHODS

A total of 53 patients who underwent nerve biopsies at our laboratory were examined: nine patients with idiopathic HES (iHES), three patients with reactive HES, 14 patients with myeloperoxidase-anti-neutrophil cytoplasmic antibody (ANCA)-positive EGPA, and 27 patients with negative EGPA. Nerve biopsies were performed using light and electron microscopy.

RESULTS

Polyneuropathy was more common than mononeuritis multiplex in iHES, which differed from that in ANCA-negative EGPA groups (p = 0.012). Nerve biopsies showed that iHES was associated with neuropathy features such as rare vasculitis and non-vasculitic eosinophilic infiltrates, which differed from those of ANCA-negative EGPA. Fibrinoid necrosis was found only in the reactive HES and ANCA-positive groups. The percentage of endoneurial vessels occluded with eosinophils tended to be higher in iHES (1.8%) than in ANCA-positive EGPA (0%) and negative EGPA (0.7%). In a patient with ANCA-negative EGPA, the endoneurial vessels were occluded with platelets, fibrinoid materials, and eosinophils, demonstrating the morphology of eosinophil extracellular traps.

CONCLUSION

iHES with neuropathy showed a pattern more similar to polyneuropathy than mononeuritis multiplex, which is dominant in ANCA-negative EGPA, and tended to show vasculitis in the peripheral nerves less frequently compared with EGPA. Eosinophilic infiltration and endoneurial vascular occlusion by eosinophils may cause nerve damage.

The hypereosinophilic syndrome - an unusual cause of myocarditis and cardioembolic strokes

Hypereosinophilic syndrome is a rare disorder characterized by excessive peripheral eosinophilia and eosinophil associated end-organ damage. Clinical presentations are heterogenous and can involve skin, pulmonary, cardiac and neurologic dysfunction. Eosinophilic myocarditis is a life-threatening complication that increases the risk of cardiac microemboli, which can subsequently lead to embolic strokes. Secondary to changes in blood viscosity, impaired clearance of microemboli, impaired cerebral blood flow, and pro-thrombotic conditions in the setting of hypereosinophilia, infarcts often present in vascular border zone regions. Here we present two cases of cardioembolic strokes involving borderzone regions in the setting of hypereosinophilic syndrome.

Left Ventricular Assist Device Evaluation for Congestive Heart Failure With Hypereosinophilic Syndrome in a 76-Year-Old Male

Hypereosinophilic syndrome, a rare condition, is characterized by eosinophilia with associated organ infiltration and organ failure. The most commonly involved sites include the cardiovascular, gastrointestinal, and central nervous systems. Infiltration of eosinophils into the myocytes may result in congestive heart failure warranting the use of a left ventricular assist device (LVAD). The authors describe a case of a 76-year-old male with dyspnea and a consistently elevated eosinophil count. Initially diagnosed with adult-onset asthma, he failed to improve despite his adherence to recommended pharmacological treatment. The exacerbation of dyspnea combined with the signs of congestive heart failure led to the evaluation of LVAD therapy in this patient.

Mechanisms and Neuroimaging Patterns of Hypereosinophilia-Related Ischemic Stroke: A Narrative Review through Three Cases

Background: Hypereosinophilic syndromes (HES) are a group of relatively rare disorders in which neurological manifestations, including ischemic stroke, are common. The hypothesized pathophysiological mechanisms are hypercoagulability, cardioembolism (mainly mediated by myocardial involvement) and damage to the endothelium. A variable ischemic pattern has been described, including an association of territorial and border zone ischemic stroke. Methods: Three patients who presented to our department with acute stroke were selected aiming to show these three different mechanisms inferred from the stroke pattern on brain Magnetic Resonance Imaging (MRI) and to simultaneously illustrate the three main causes of HES. Results and Discussion: The first patient is a 55-year-old man with an abrupt onset of aphasia due to an acute ischemic stroke involving the left parietal lobule and the angular gyrus; recent lab test had shown hypereosinophilia. An extensive workup excluded primary and secondary causes of hypereosinophilia so a diagnosis of idiopathic hypereosinophilia was done and he was treated with high doses of steroids. The second patient had severe hypereosinophilia and developed multiple small, scattered ischemic lesions, mainly in border zone zones. The history of severe asthma and recurrent sinusitis supported the diagnosis of EGPA (Eosinophilic Granulomatosis with Polyangiitis); considering the severe clinical conditions and the presumptive role of hypereosinophilia in determining her symptoms, steroid treatment was promptly started, with good clinical response. The third patient also presented with multiple metachronous ischemic lesions, both in cortical and border zone distribution and marked eosinophilia; the diagnostic work-up found an ovarian cancer. She was treated with steroids and then underwent surgery and adjuvant chemotherapy. Conclusions: HES should be considered in stroke etiological evaluation, although it is a rare disorder, and border zones pattern without large artery steno-occlusion on neuroimaging may help to raise the suspicion in the neurovascular diagnostic pathway. A thorough research of the sources of hypereosinophilia should be performed to select the appropriate therapy.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

Clinical Trial Registration

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

Imaging patterns of cerebral ischemia in hypereosinophilic syndrome: case report and systematic review

INTRODUCTION

Ischemic stroke is a potential complication of hypereosinophilic syndromes (HES), and little is known about underlying pathophysiological mechanisms. We aimed to describe the imaging patterns of cerebral ischemia in patients with HES.

METHODS

An individual case is reported. A systematic PubMed review of all records reporting adult patients with HES who suffered ischemic stroke and for whom neuroimaging details of ischemic lesions were available was performed.

RESULTS

A 60-year-old man presented with progressive subacute gait difficulty and psychomotor slowing as well as an absolute eosinophilia (2.2 × 109/L) at admission. Brain magnetic resonance tomography revealed multiple acute and subacute internal and external border zone infarcts. Cardiac diagnostic suggested the presence of endomyocarditis. After extensive diagnostic workup, idiopathic HES was diagnosed. The systematic review yielded 183 studies, of which 40 fulfilled the inclusion criteria: a total of 64 patients (31.3% female), with mean age 51.1 years and a median absolute eosinophile count at diagnosis of 10.2 × 109/L were included in the analyses. A border zone pattern of cerebral ischemic lesions was reported in 41 patients (64.1%). Isolated peripheral infarcts were reported in 7 patients (10.9%). Sixteen patients had multiple acute infarcts with no border zone distribution (25.0%). An intracardiac thrombus was reported in 15/60 patients (25%), and findings suggestive of endomyocarditis or endomyocardial fibrosis were found in 31/60 patients (51.7%).

CONCLUSIONS

Border zone distribution of cerebral ischemia without hemodynamic compromise is the most frequent imaging pattern in patients with HES, occurring in 2/3 of patients who develop ischemic stroke.

Current and emerging biologic therapies targeting eosinophilic disorders

Eosinophilic disorders include a wide array of conditions in which eosinophils play a primary pathophysiologic role. While historically treated with corticosteroids and immunosuppressants, knowledge of eosinophil biology has led to the development of several biologics targeting eosinophils. In this review, we discuss the current US Food and Drug Administration (FDA) approved eosinophil-specific biologics targeting IL-5 (mepolizumab and reslizumab) and IL-5R (benralizumab) along with biologics under investigation targeting siglec-8 (lirentelimab). We discuss efficacy and safety data from trials of these medications in conditions including eosinophilic asthma, hypereosinophilic syndrome (HES), eosinophilic granulomatosis with polyangiitis (EGPA), chronic rhinosinusitis with nasal polyposis (CRSwNP), eosinophilic esophagitis (EoE), and eosinophilic gastrointestinal disease (EGID). Additionally, we discuss case reports utilizing these medications in conditions including drug reaction with eosinophilia and systemic symptoms (DRESS), allergic bronchopulmonary aspergillosis (ABPA), and eosinophilic pneumonia, among others. While eosinophilic targeting biologic therapy has been successful in eosinophilic asthma, HES, EGPA, and CRSwNP leading to FDA approval for these conditions, trials treating EoE and EGID have been disappointing to date. Given the increasing number of trials utilizing these biologics, it will be imperative for the allergist-immunologist to stay up to date on the latest treatment options to provide the most optimal care for eosinophilic disorders.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Rare Case of a Young Male Presented with Abdominal Pain, Solid Colon Tumors, and Eosinophilia, Followed by Tremendous Thromboembolic Complications and Eventually Diagnosed with Idiopathic Hypereosinophilic Syndrome

Hypereosinophilic syndrome (HES) is a rare condition characterized by profound peripheral eosinophilia and various organ dysfunction. Diagnostic criteria and classification of this challenging medical entity changed over time. Elevated absolute eosinophil count with extensive tissue infiltration and signs of organ damage of unknown origin is termed idiopathic HES. Hypereosinophilia is a highly hypercoagulable state; thus, a variety of thromboembolic complications may occur. Only a few reports of idiopathic HES patients with different forms of thrombosis are being published. We document a case of a young male presented with persistent abdominal pain with two eosinophilic colon tumors. The patient suffered from phlegmasia cerulea dolens and portal vein thrombosis, followed by pulmonary embolism and overt disseminated intravascular coagulation (DIC). Corticosteroids successfully reduced and controlled eosinophil level while skilled anticoagulation and supportive management overcome DIC-associated complications.

Drug Reaction with Eosinophilia and Systemic Symptoms (DReSS)/Drug-Induced Hypersensitivity Syndrome (DiHS)—Readdressing the DReSS

Drug reaction with eosinophilia and systemic symptoms (DReSS), also known as drug-induced hypersensitivity syndrome (DiHS), is a severe, systemic, T cell mediated drug reaction with combinations of cutaneous, hematologic, and internal organ involvement. Pathogenesis of DReSS is multi-factorial, involving drug-exposure, genetic predisposition through specific human leukocyte antigen (HLA) alleles and metabolism defects, viral reactivation, and immune dysregulation. Clinical features of this condition are delayed, stepwise, and heterogenous, making this syndrome challenging to recognize and diagnose. Two sets of validated diagnostic criteria exist that can be employed to diagnose DReSS/DiHS. Methods to improve early recognition of DReSS and predict disease severity has been a recent area of research focus. In vitro and in vivo tests can be employed to confirm the diagnosis and help identify culprit drugs. The mainstay treatment of DReSS is prompt withdrawal of the culprit drug, supportive treatment, and immunosuppression depending on the severity of disease. We present a comprehensive review on the most recent research and literature on DReSS, with emphasis on pathogenesis, clinical features, diagnosis, confirmatory testing modalities, and treatment. Additionally, this summary aims to highlight the differing viewpoints on this severe disease and broaden our perspective on the condition known as DReSS.

Hypereosinophilic syndrome presenting as acute ischemic stroke, myocardial infarction, and arterial involvement: A case report

BACKGROUND

Simultaneous cerebral and myocardial infarction with arterial involvement has not been reported in hypereosinophilic syndrome (HES). Here, we report a patient with HES that was also associated with acute ischemic stroke, myocardial infarction, and arterial involvement of the left common carotid artery, vertebral arteries, posterior cerebral artery, and coronary artery.

CASE SUMMARY

A 64-year-old male patient was admitted with headache and right lower extremity weakness. Laboratory tests indicated eosinophilia. Brain magnetic resonance imaging (MRI) showed bilateral and multiple acute infarcts in the border zones. Electrocardiography revealed that T wave was inverted and that the concentration of troponin I was significantly elevated above normal levels. Cardiac echocardiography showed an ejection fraction of 69% with mitral and tricuspid mild regurgitation. Computed tomography angiography detected multiple and localized instances of mild stenosis in the left common carotid artery bifurcation, bilateral vertebral arteries (V5 segment), and the posterior cerebral artery (P2 segment). These were observed together with multiple non-calcified and mixed plaques as well as luminal stenosis in the left circumflex artery, left anterior descending artery, and right coronary artery. The patient was treated with oral methylprednisolone and clopidogrel, after which the absolute eosinophil count fell rapidly to a normal level. After one month, a second brain MRI showed a partial reduction in the size and number of the lesions.

CONCLUSION

HES can masquerade as ischemic stroke, myocardial infarction, and arterial vascular involvement. The patient reported here recovered very quickly when his eosinophil blood count returned to normal. Early diagnosis and rapid reduction of eosinophils may lead to a good prognosis.

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

Background

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

Methods

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

Results

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

Conclusions

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

Clinical Trial Registration

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

Hypereosinophilic syndrome presenting as coagulopathy

Background

Hypereosinophilic syndrome (HES) is an extremely uncommon group of disorders. It rarely presents with coagulopathy without cardiac involvement.

Case presentation

A 33-year-old previously healthy male with no history of atopic disease presented with abdominal pain, hematochezia, peripheral eosinophilia as high as 10,000 eos/µL, right and left portal vein, mesenteric, and splenic vein thrombi with ischemic colitis resulting in hemicolectomy and small bowel resection. Despite an extensive workup for primary and secondary etiologies of hypereosinophilia by hematology/oncology, infectious disease, rheumatology and allergy/immunology, no other clear causes were identified, and the patient was diagnosed with idiopathic HES. His eosinophilia was successfully treated with high-dose oral corticosteroids (OCS) and subsequently transitioned to anti-IL-5-receptor therapy with benralizumab. He has continued this treatment for over a year with no recurrence of eosinophilia or thrombosis while on benralizumab.

Conclusion

In patients with an unexplained coagulopathy and eosinophilia, eosinophilic disorders such as HES should be considered. Corticosteroid-sparing agents, such as benralizumab show promise for successfully treating these patients.

Eosinophilic airway diseases: basic science, clinical manifestations and future challenges

Eosinophils have a broad range of functions, both homeostatic and pathological, mediated through an array of cell surface receptors and specific secretory granules that promote interactions with their microenvironment. Eosinophil development, differentiation, activation, survival and recruitment are closely regulated by a number of type 2 cytokines, including interleukin (IL)-5, the key driver of eosinophilopoiesis. Evidence shows that type 2 inflammation, driven mainly by interleukin (IL)-4, IL-5 and IL-13, plays an important role in the pathophysiology of eosinophilic airway diseases, including asthma, chronic rhinosinusitis with nasal polyps, eosinophilic granulomatosis with polyangiitis and hypereosinophilic syndrome. Several biologic therapies have been developed to suppress type 2 inflammation, namely mepolizumab, reslizumab, benralizumab, dupilumab, omalizumab and tezepelumab. While these therapies have been associated with clinical benefits in a range of eosinophilic diseases, their development has highlighted several challenges and directions for future research. These include the need for further information on disease progression and identification of treatable traits, including clinical characteristics or biomarkers that will improve the prediction of treatment response. The Nordic countries have a long tradition of collaboration using patient registries and Nordic asthma registries provide unique opportunities to address these research questions. One example of such a registry is the NORdic Dataset for aSThmA Research (NORDSTAR), a longitudinal population-based dataset containing all 3.3 million individuals with asthma from four Nordic countries (Denmark, Finland, Norway and Sweden). Large-scale, real-world registry data such as those from Nordic countries may provide important information regarding the progression of eosinophilic asthma, in addition to clinical characteristics or biomarkers that could allow targeted treatment and ensure optimal patient outcomes.