Hypereosinophilic Syndrome

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

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

Idiopathic Hypereosinophilic Syndrome Presenting With Embolic Stroke

Hypereosinophilic syndrome is a rare condition characterized by eosinophilia associated with organ damage, most commonly affecting the skin, lung, gastrointestinal, cardiovascular and central nervous system. The idiopathic form is characterized by the absence of other conditions associated with hypereosinophilia such as allergies, infectious, hematological, immunological, endocrine or neoplasm diseases. The authors present a clinical case of a 70-year-old man with no relevant history, who went to the emergency department for neurological deficits and nonspecific chest pain. Laboratory tests revealed marked eosinophilia, elevation of cardiac enzymes with normal electrocardiogram. Computed tomography of the head showed multiple bilateral ischemic lesions. Upon further investigation for the cerebrovascular disease, transesophageal echocardiogram showed a thrombus at the aortic arch, as a probable embolic source. Despite anticoagulant therapy and corticosteroids, the patient's status deteriorated, with multiple successive ischemic strokes and worsening neurological deficits. After a thorough investigation, the diagnosis of idiopathic eosinophilia was established.

Eosinophils in Health and Disease: A State-of-the-Art Review

Eosinophils play a homeostatic role in the body's immune responses. These cells are involved in combating some parasitic, bacterial, and viral infections and certain cancers and have pathologic roles in diseases including asthma, chronic rhinosinusitis with nasal polyps, eosinophilic gastrointestinal disorders, and hypereosinophilic syndromes. Treatment of eosinophilic diseases has traditionally been through nonspecific eosinophil attenuation by use of glucocorticoids. However, several novel biologic therapies targeting eosinophil maturation factors, such as interleukin (IL)-5 and the IL-5 receptor or IL-4/IL-13, have recently been approved for clinical use. Despite the success of biologic therapies, some patients with eosinophilic inflammatory disease may not achieve adequate symptom control, underlining the need to further investigate the contribution of patient characteristics, such as comorbidities and other processes, in driving ongoing disease activity. New research has shown that eosinophils are also involved in several homeostatic processes, including metabolism, tissue remodeling and development, neuronal regulation, epithelial and microbiome regulation, and immunoregulation, indicating that these cells may play a crucial role in metabolic regulation and organ function in healthy humans. Consequently, further investigation is needed into the homeostatic roles of eosinophils and eosinophil-mediated processes across different tissues and their varied microenvironments. Such work may provide important insights into the role of eosinophils not only under disease conditions but also in health. This narrative review synthesizes relevant publications retrieved from PubMed informed by author expertise to provide new insights into the diverse roles of eosinophils in health and disease, with particular emphasis on the implications for current and future development of eosinophil-targeted therapies.

Safety and efficacy of mepolizumab in hypereosinophilic syndrome: an open-label extension study

BACKGROUND

A double-blind, placebo-controlled Phase III study (200622) showed that mepolizumab reduces disease flares for patients with uncontrolled FIP1L1-PDGFRA-negative hypereosinophilic syndrome (HES) and ≥2 flares in the previous year.

OBJECTIVES

To further characterize the safety, clinical benefit, and pharmacodynamics of mepolizumab.

METHODS

Eligible patients from both treatment arms of the double-blind study could enter an open-label extension (OLE) study (205203; NCT03306043) to receive 4-weekly mepolizumab (300 mg subcutaneously) plus background therapy for 20 weeks. Primary endpoints were safety-based; other endpoints included flare rates and changes from baseline in mean daily oral corticosteroid (OCS) dose and blood eosinophil count (BEC).

RESULTS

Of 104 patients who completed the double-blind study, 98% (previous placebo n=52; previous mepolizumab n=50) enrolled in the OLE. Overall, 66 (65%) patients reported adverse events (AEs); 15 (15%) reported treatment-related AEs and 9 (9%) reported serious AEs. No events were fatal. The annualized flare rate (95% confidence interval) in the previous placebo and previous mepolizumab groups was 0.37 (0.16, 0.86) and 0.14 (0.04, 0.49) events/year, respectively. Of 72 patients receiving OCS during Weeks 0-4, 20 (28%; previous placebo, n=14; previous mepolizumab, n=6) achieved ≥50% reductions in mean daily dose during Weeks 16-20. At Week 20, BEC was reduced by 89% in patients previously receiving placebo and remained reduced for those previously receiving mepolizumab.

CONCLUSION

Extended mepolizumab treatment was associated with a positive benefit:risk profile. Continued control of disease flares and blood eosinophil counts, plus reductions in OCS use, were observed with mepolizumab in patients with FIP1L1-PDGFRA-negative HES.

The increasing incidence and prevalence of hypereosinophilic syndrome in the United Kingdom

Introduction

Data on the burden of hypereosinophilic syndrome (HES) are limited. This study investigated the incidence and prevalence of HES using real‐world data from patients in the United Kingdom.

Methods

Primary care data from the Clinical Practice Research Datalink were analyzed. The patients of interest were identified using medical codes specific for HES. Annual incidence rates and prevalence were estimated for the years 2010–2018 (inclusive) using patients observed for a minimum period of one year.

Results

Between 2010 and 2018, 93 patients were identified with HES. During the study period the incidence of HES ranged from less than 0.04, 95% confidence interval (CI) (0.01–0.07) to 0.17, 95% CI (0.10–0.26) per 100,000 person‐years and the prevalence ranged from 0.15, 95% CI (0.10–0.25) to 0.89, 95% CI (0.74–1.09) cases per 100,000 persons. Sensitivity analyses varying the minimum observation period required to identify HES patients gave similar results.

Conclusion

These results provide estimates of the burden of HES in the United Kingdom and indicate that whilst HES is a very rare disease, there is evidence that is increasingly being recorded in UK primary care.

Transcutaneous neurostimulatory treatment for peripheral polyneuropathy induced by hypereosinophilic syndrome - A case report

Background

Hypereosinophilic syndrome is a rare disease that increases the number of circulating eosinophils in the body. It has many complications, including peripheral polyneuropathy. Peripheral polyneuropathy often does not respond well to conventional therapies. Transcutaneous neurostimulatory treatment, also known as scrambler therapy, is an alternative modality for the treatment of chronic retractable pain.

Case

A 47-year-old female presented with complaints of bilateral calf pain. She had been under treatment for peripheral polyneuropathy induced by hypereosinophilic syndrome for 7 years. Pharmacologic treatment did not affect the patient’s symptoms.

Conclusions

Transcutaneous neurostimulatory treatment was administered to the patient. It was effective on her symptoms, and the effect of pain alleviation continued for 3 months.

A Phase 1 study of the long-acting anti-IL-5 monoclonal antibody GSK3511294 in patients with asthma

Aims

GSK3511294 is a humanized anti‐interleukin (IL)‐5 monoclonal antibody (mAb) engineered for extended half‐life and improved IL‐5 affinity versus other anti‐IL‐5 mAbs. This study examined its safety, tolerability, pharmacokinetics (PK) and effect on blood eosinophil counts.

Methods

This was a double‐blind, parallel‐group, single‐ascending‐dose, multicenter, Phase 1 study (205 722;NCT03287310) in patients with asthma and a blood eosinophil count ≥200 cells μL⁻¹. Patients were randomized 3:1 within dose cohorts to receive a single subcutaneous dose of GSK3511294 (2, 10, 30, 100 or 300 mg) or placebo and followed for up to 40 weeks to assess safety (primary endpoint), ratio to baseline in blood eosinophil count, plasma PK parameters and frequency/titers of binding antidrug antibodies (all secondary).

Results

Forty‐eight patients received the study drug and completed the study. Adverse events (AEs) occurred in 92% of placebo‐treated and 81% of GSK3511294‐treated patients. There were no AEs leading to study withdrawal or serious AEs; hypersensitivity (one event in one patient) and injection‐site reaction (three events in two patients) occurred infrequently. Marked reductions (>48%) in blood eosinophil count were seen from 24 hours post‐dose with all GSK3511294 doses but not placebo; suppression was maintained for longer with increasing dose (82% and 83% adjusted reductions vs placebo with 100 and 300 mg, respectively, at week 26). PK were linear and dose proportional over the dose range; terminal half‐life was 38‐53 days.

Conclusions

GSK3511294 was well tolerated, with linear and dose proportional PK, extended half‐life and blood eosinophil count reduction, supporting less frequent dosing versus other anti‐IL‐5 mAbs.

A Retrospective Review of 193 Cases of Severe Eosinophilia in the Northeast United States

BACKGROUND

This retrospective review evaluated the causes of severe eosinophilia (≥5000 eosinophils/L). Higher eosinophilia levels are more likely to cause tissue damage and may reflect disease severity.

METHODS

We reviewed 193 cases of patients seen at Beth Israel Deaconess Medical Center in Boston, Massachusetts, and at the University of Vermont Medical Center in Burlington, Vermont, between January 2015 to May 2020 who had a peak absolute eosinophil count of at least 5000/μL.

RESULTS

Thirty-nine percent of cases were attributable to a hematologic or oncologic cause. These cases had the highest mean peak absolute eosinophil count at 11,698/μL. Twenty percent of cases were secondary to drug reactions, of which 90% took place in an inpatient setting. Three percent of cases were from helminthic infection, the majority of which were in returning travelers.

CONCLUSIONS

In our region of study, hematologic and oncologic cases are important causes of severe eosinophilia, drug reactions are a common etiology in the inpatient setting, and infections are a rare cause.

Eosinophils and eosinophil-associated disorders: immunological, clinical, and molecular complexity

Eosinophils and their mediators play a crucial role in various reactive states such as bacterial and viral infections, chronic inflammatory disorders, and certain hematologic malignancies. Depending on the underlying pathology, molecular defect(s), and the cytokine- and mediator-cascades involved, peripheral blood and tissue hypereosinophilia (HE) may develop and may lead to organ dysfunction or even organ damage which usually leads to the diagnosis of a HE syndrome (HES). In some of these patients, the etiology and impact of HE remain unclear. These patients are diagnosed with idiopathic HE. In other patients, HES is diagnosed but the etiology remains unknown — these patients are classified as idiopathic HES. For patients with HES, early therapeutic application of agents reducing eosinophil counts is usually effective in avoiding irreversible organ damage. Therefore, it is important to systematically explore various diagnostic markers and to correctly identify the disease elicitors and etiology. Depending on the presence and type of underlying disease, HES are classified into primary (clonal) HES, reactive HES, and idiopathic HES. In most of these patients, effective therapies can be administered. The current article provides an overview of the pathogenesis of eosinophil-associated disorders, with special emphasis on the molecular, immunological, and clinical complexity of HE and HES. In addition, diagnostic criteria and the classification of eosinophil disorders are reviewed in light of new developments in the field.

Eosinophils as Major Player in Type 2 Inflammation: Autoimmunity and Beyond

Eosinophils are a subset of differentiated granulocytes which circulate in peripheral blood and home in several body tissues. Along with their traditional relevance in helminth immunity and allergy, eosinophils have been progressively attributed important roles in a number of homeostatic and pathologic situations. This review aims at summarizing available evidence about eosinophils functions in homeostasis, infections, allergic and autoimmune disorders, and solid and hematological cancers.Their structural and biological features have been described, along with their physiological behavior. This includes their chemokines, cytokines, granular contents, and extracellular traps. Besides, pathogenic- and eosinophilic-mediated disorders have also been addressed, with the aim of highlighting their role in Th2-driven inflammation. In allergy, eosinophils are implicated in the pathogenesis of atopic dermatitis, allergic rhinitis, and asthma. They are also fundamentally involved in autoimmune disorders such as eosinophilic esophagitis, eosinophilic gastroenteritis, acute and chronic eosinophilic pneumonia, and eosinophilic granulomatosis with polyangiitis. In infections, eosinophils are involved in protection not only from parasites but also from fungi, viruses, and bacteria. In solid cancers, local eosinophilic infiltration is variably associated with an improved or worsened prognosis, depending on the histotype. In hematologic neoplasms, eosinophilia can be the consequence of a dysregulated cytokine production or the result of mutations affecting the myeloid lineage.Recent experimental evidence was thoroughly reviewed, with findings which elicit a complex role for eosinophils, in a tight balance between host defense and tissue damage. Eventually, emerging evidence about eosinophils in COVID-19 infection was also discussed.

Crusted Scabies Induced Hypereosinophilic Syndrome

Crusted scabies causes extensive hyperkeratotic skin lesions, crusting, and scaling and is common in elderly and institutionalized patients. We present a case of crusted scabies in a patient with encephalopathy and diffuse exfoliative erythroderma. After extensive workup, the patient’s condition was attributed to hypereosinophilic syndrome due to crusted scabies. Skin condition, mental status, and eosinophilia improved with high-dose steroids in conjunction with topical permethrin and oral ivermectin.

What does elevated TARC/CCL17 expression tell us about eosinophilic disorders?

Eosinophilic disorders encompass a large spectrum of heterogeneous diseases sharing the presence of elevated numbers of eosinophils in blood and/or tissues. Among these disorders, the role of eosinophils can vary widely, ranging from a modest participation in the disease process to the predominant perpetrator of tissue damage. In many cases, eosinophilic expansion is polyclonal, driven by enhanced production of interleukin-5, mainly by type 2 helper cells (Th2 cells) with a possible contribution of type 2 innate lymphoid cells (ILC2s). Among the key steps implicated in the establishment of type 2 immune responses, leukocyte recruitment toward inflamed tissues is particularly relevant. Herein, the contribution of the chemo-attractant molecule thymus and activation-regulated chemokine (TARC/CCL17) to type 2 immunity will be reviewed. The clinical relevance of this chemokine and its target, C-C chemokine receptor 4 (CCR4), will be illustrated in the setting of various eosinophilic disorders. Special emphasis will be put on the potential diagnostic, prognostic, and therapeutic implications related to activation of the TARC/CCL17-CCR4 axis.

Episodic angioedema with eosinophilia (Gleich's syndrome) associated with urticarial vasculitis: a coincidence or a novel clinical entity?

Episodic angioedema with eosinophilia (EAE) is a rare condition characterized by recurrent attacks of angioedema and urticaria accompanied by a marked elevation of peripheral eosinophil count. We report the case of a young female patient diagnosed with EAE associated with urticarial vasculitis. A 40-year-old female patient was admitted to our institution due to recurrent episodes of cheek and eyelid angioedema in the previous year. Episodes of facial angioedema lasted for two months with spontaneous remission afterwards. In addition, she presented pruritic and painful skin eruptions of erythematous circles, which persisted for longer than 24 h, that were palpable, somewhat purplish, and more pronounced on the face, arms, and trunk. Laboratory investigation showed a sustained elevation of white cell counts with marked eosinophilia. Serum IgM, IgE, and IgA were normal; IgG was slightly elevated. C1-esterase inhibitor and tryptase test were normal. Reverse transcriptase-polymerase chain reaction was performed for detection of FIP1L1-PDGFRA and BCR-ABL rearrangements. None of these alterations were found. Skin biopsies were suggestive of urticarial vasculitis. The patient was submitted to esophagogastroduodenoscopy, which showed mild chronic gastritis, with no eosinophilic infiltration. Cardiac dimensions and function were normal. Abdominal ultrasound and total body CT-scan failed to show lymphadenopathy, organomegaly, and tumors. We report the first case of association between episodic angioedema with eosinophilia and urticarial vasculitis. It is possible that both conditions share a physiopathological mechanism, suggesting that it is not just a chance association.

[Multiple cerebral infarctions in the deep perforator regions in a case of idiopathic hypereosinophilic syndrome]

A 61-year-old man was admitted to our hospital due to cerebral infarction in the pons and the right putamen. On admission (day 3 from symptom onset), laboratory testing showed a white blood cell count of 13,100/μl with hypereosinophilia of 3,734/μl. As deep vein thrombosis was detected on contrast-enhanced CT, we started anticoagulation therapy. There were no cardio-embolic sources, including right-to-left shunt, but eosinophil infiltration was found in biopsy specimens of the gastric mucosa. These findings allowed us to diagnose multiple perforator infarction due to idiopathic hypereosinophilic syndrome (idiopathic HES). After the administration of oral prednisolone was started on day 10, his hypereosinophilia rapidly improved, and no recurrence of deep perforator infarction occurred other than a symptomatic infarction in the left putamen at day 19. There are a few reports of idiopathic HES with multiple infarctions developing in deep perforator regions. The current case suggests that idiopathic HES could cause multiple cerebral infarction restricted to deep perforator areas.

Investigating Febrile Polyserositis: An Unusual Case of Idiopathic Hypereosinophilic Syndrome

Hypereosinophilic syndrome (HES) is a heterogenous group of diseases characterized by abnormal accumulation of eosinophils in the blood or peripheral tissues. It can affect all organs and therefore clinical manifestations are highly variable. We describe the case of a 38-year-old man admitted for febrile polyserositis. He developed cardiac tamponade requiring pericardiocentesis complicated by left ventricle perforation which was successfully repaired. He presented mild peripheral eosinophilia. Bronchoalveolar lavage evidenced eosinophilic alveolitis, and pleural and pericardium histopathology revealed the presence of abundant eosinophils. All other causes of tissue eosinophilia were excluded and the diagnosis of idiopathic HES was made. The patient was started on glucocorticoids with resolution of symptoms. This case report describes a rare but potentially fatal presentation of HES and demonstrates the difficulty and delay in diagnosis when peripheral hypereosinophilia is absent.

LEARNING POINTS

Hypereosinophilic syndrome (HES) is characterized by abnormal accumulation of eosinophils in the blood or peripheral tissues.The clinical manifestations of HES are highly variable.It may be difficult to diagnose HES when peripheral hypereosinophilia is absent.

Eosinophilic granulomatosis with polyangiitis: understanding the disease and its management

Eosinophilic granulomatosis with polyangiitis is characterized by asthma, blood and tissue eosinophilia and small-vessel vasculitis. The clinical presentation is variable, but two main clinic-pathologic subsets can be distinguished: one hallmarked by positive ANCA and predominant 'vasculitic' manifestations (e.g. glomerulonephritis, purpura and mononeuritis multiplex) and the other by negative ANCA and prominent 'eosinophilic' manifestations (e.g. lung infiltrates and cardiomyopathy). The pathogenesis is not fully understood but probably results from the interplay between T and B cells and eosinophils. Eosinophilic granulomatosis with polyangiitis must be differentiated from several conditions, including hypereosinophilic syndromes and other small-vessel vasculitides. The overall survival is good; however, patients frequently relapse and have persistent symptoms. The recently developed monoclonal antibodies targeting B cells and eosinophilopoietic cytokines such as IL-5 are emerging as valid alternatives to conventional immunosuppressive therapies. In this review, we discuss the essential features of eosinophilic granulomatosis with polyangiitis, with particular respect to the most relevant issues concerning clinical presentation and management.

Hypereosinophilic syndrome with multiorgan involvement: an interdisciplinary work-up

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

Efficacy and safety of mepolizumab in hypereosinophilic syndrome: A phase III, randomized, placebo-controlled trial

BACKGROUND

Anti-IL-5 therapy is a potential treatment for patients with hypereosinophilic syndrome (HES), although its clinical efficacy is unclear.

OBJECTIVE

We sought to investigate the clinical efficacy and safety of mepolizumab versus placebo in patients with HES.

METHODS

This randomized, multicenter, double-blind, placebo-controlled, phase III trial was conducted across 39 centers in 13 countries. Eligible patients had FIP1L1-PDGFRA-negative HES, experienced 2 or more flares (worsening of HES-related symptoms or blood eosinophil count requiring therapeutic escalation) in the previous 12 months, and had a screening blood eosinophil count greater than or equal to 1000 cells/μL. Patients were randomized (1:1) to subcutaneous mepolizumab (300 mg) or placebo every 4 weeks for 32 weeks, plus existing HES therapy. The primary outcome was the proportion of patients with 1 or more flares (worsening of HES-related symptoms necessitating therapy escalation or ≥2 courses of blinded rescue oral corticosteroids) during the study; in addition, patients who withdrew early from the study were counted as having a flare. Safety end points were also assessed.

RESULTS

The proportion of patients experiencing 1 or more flares/withdrawing from the study was 50% lower with mepolizumab versus placebo (15 of 54 [28%] vs 30 of 54 [56%]; P = .002). Logistic regression analysis was consistent with the primary analysis (odds ratio, 0.28; 95% CI, 0.12-0.64; P = .003). Similar proportions of patients in the mepolizumab and placebo groups experienced on-treatment adverse events (48 of 54 [89%] vs 47 of 54 [87%]).

CONCLUSIONS

Compared with placebo, mepolizumab significantly reduced the occurrence of flares in patients with HES, with no new safety signals identified.

Multiple Biological Aspects of Eosinophils in Host Defense, Eosinophil-Associated Diseases, Immunoregulation, and Homeostasis: Is Their Role Beneficial, Detrimental, Regulator, or Bystander?

Eosinophils are innate immune leukocytes and play important roles as terminal effector cells owing to their mediators, such as tissue-destructive cationic proteins, cytokines, chemokines, and lipid mediators. Historically, they are not only considered an important player in host defense against parasitic, viral, fungal, and bacterial infections but also implicated in the pathogenesis of eosinophil-associated diseases, such as allergic rhinitis, asthma, eosinophilic chronic rhinosinusitis, esophagitis, atopic dermatitis, myopathies, and hypereosinophilic syndrome. Moreover, recent studies have shown that eosinophils have an immune regulatory and homeostatic function. Interestingly, there is emerging evidence that eosinophils are accumulated through adoptive T-helper 2 (Th2) and innate Th2 responses, mechanisms of the classical allergen-specific immunoglobulin E (IgE)-mediated response, and group 2 innate lymphoid cell-derived interleukin-5, respectively. Furthermore, in agreement with current concepts of eosinophil subtypes, it has been shown that resident and phenotypically distinct eosinophils, i.e., resident and recruited inflammatory eosinophils, exist in inflamed sites, and each has different functions. Thus, the classical and novel studies suggest that eosinophils have multiple functions, and their roles may be altered by the environment. In this article, we review multiple biological aspects of eosinophils (novel and classical roles), including their beneficial and detrimental effects, immunoregulation, and homeostatic function.

Hypersensitivity pneumonitis, allergic bronchopulmonary aspergillosis and other eosinophilic lung diseases

Hypersensitivity pneumonitis (HP) is traditionally classified into acute, subacute and chronic forms. A high index of suspicion and a detailed investigation into the patient's environment is the key to diagnosis and treatment of HP. Eosinophilic lung diseases can be broadly categorized as idiopathic (acute eosinophilic pneumonia, chronic eosinophilic pneumonia, eosinophilic granulomatosis with polyangiitis and hypereosinophilic syndromes), those with known cause (allergic bronchopulmonary aspergillosis, drugs, parasitic and non-parasitic infections), and those associated with other known lung diseases (asthma, interstitial lung diseases and lung cancers). A detailed review of drug intake, toxin exposures, and travel history is essential in the differential diagnosis of eosinophilic lung diseases.

The emerging role of Janus kinase inhibitors in the treatment of autoimmune and inflammatory diseases

Autoimmune and inflammatory diseases are common and diverse, and they can affect nearly any organ system. Much of the pathogenesis of these diseases is related to dysregulated cytokine activity. Historically, autoimmune and inflammatory diseases have been treated with medications that nonspecifically suppress the immune system. mAbs that block the action of pathogenic cytokines emerged 2 decades ago and have become widely useful. More recently, agents that simultaneously block multiple pathogenic cytokines via inhibition of the downstream Janus kinase (JAK)-signal transducer and activator of transcription pathway have emerged and are becoming increasingly important. These small-molecule inhibitors, collectively termed JAK inhibitors, are US Food and Drug Administration-approved in a few autoimmune/inflammatory disorders and are being evaluated in many others. Here, we review the biology of the JAK-signal transducer and activator of transcription pathway and the use of JAK inhibitors to treat autoimmune and inflammatory diseases across medical subspecialties.

Acute progressive stroke with middle cerebral artery occlusion caused by idiopathic hypereosinophilic syndrome: a case report

Background

Idiopathic hypereosinophilic syndrome (IHES) is associated with various organ system dysfunctions. Neurologic abnormalities have been previously noted in this syndrome. Cerebral infarction secondary to occlusion of large cerebral artery is rarely reported. Here we described a patient with IHES presented progressive multiple cerebral infarctions caused by bilateral middle cerebral artery occlusion.

Case presentation

A 55-year-old Chinese woman presented to our hospital with acute onset of right limbs weakness and slurred speech. Laboratory tests showed a significant eosinophilia of 5.29 × 10⁹/L (normal, < 0.5), 49.9% of leukocytes. Brain magnetic resonance imaging (MRI) revealed multiple acute cerebral ischemic lesions. Magnetic resonance angiography (MRA) demonstrated stenosis in horizontal segment of right middle cerebral artery. A pretibial skin biopsy revealed eosinophilic infiltration around the capillaries in deep dermis and adipose tissue. The patient was given oral dual anti platelet agents and intravenous methylprednisolone. However, one week later, the patient presented significant neurological deterioration with right-sided hemiparesis and totally motor aphasia. Brain MRI and computed tomography perfusion (CTP) demonstrated new acute cerebral ischemia in left hemisphere. Digital subtraction angiography (DSA) revealed left middle cerebral artery completely occluded. The patient received a high-dose of intravenous methylprednisolone 500 mg per day and the eosinophil count quickly fell to normal within 2 days. She was transferred to a rehabilitation center and her neurological symptoms improved with modified Ranking Scale from 4 to 2.

Conclusions

IHES is one of the rare causes of acute ischemic stroke with large cerebral artery occlusion. An early high-dose of corticosteroids therapy should be considered in cases of IHES patients. Our case study is benefit to clinical diagnosis and treatment of cerebral infarction with IHES.

Eosinophilic Dermatoses: Recognition and Management

Eosinophilic dermatoses encompass a broad spectrum of diseases of different etiologies hallmarked by eosinophilic infiltration of the skin and/or mucous membranes, with or without associated blood eosinophilia. The wide range of dermatological manifestations of this spectrum, including nodules and plaques, pustules, blisters, ulcers, and urticarial lesions, is reflected in a non-univocal classification system. We identified six groups of eosinophilic dermatoses based on the predominant anatomic level of involvement: (1) epidermal; (2) of the dermal-epidermal junction; (3) dermal; (4) of the hypodermis and muscle fascia; (5) of the pilosebaceous unit; and (6) vascular/perivascular. We review clinicopathologic features and management of diseases belonging to each group, particularly: (1) pemphigus herpetiformis and atopic dermatitis as prototypes of the epidermal group; (2) bullous pemphigoid as prototypic eosinophilic dermatosis of the dermal-epidermal junction; (3) eosinophilic cellulitis (Wells syndrome), hypereosinophilic syndromes, Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) syndrome, eosinophilic dermatosis of hematologic malignancy and chronic spontaneous urticaria as paradigmatic dermal eosinophilic dermatoses; (4) eosinophilic fasciitis as an eosinophilic dermatosis with predominant involvement of the hypodermis and muscle fascia; (5) eosinophilic pustular folliculitis as a model of the pilosebaceous unit involvement; and (6) granuloma faciale, angiolymphoid hyperplasia with eosinophilia, and eosinophilic granulomatosis with polyangiitis, belonging to the vascular/perivascular group.

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

Background

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

Case presentation

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

Conclusion

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

Diagnostic procedure for idiopathic eosinophilic pleural effusion: a single-center experience

Background

Eosinophilic pleural effusion (EPE) is attributed to several well-recognised causes. However, some patients remain idiopathic, even after thorough clinical work-up. The present study aimed to better characterize idiopathic EPE (IEPE) and to outline the diagnostic procedure for this disease.

Methods

Complete clinical data of 11 consecutive patients with IEPE were prospectively collected and analysed. Preliminary diagnostic procedure of IEPE in our hospital was performed.

Results

All the 11 patients had respiratory symptoms and unilateral pleural effusion (PE) occurred in 4 patients. The mean percentage of eosinophils in PE was 22.4% (range, 12.4–50.5%). Lactate dehydrogenase, adenosine deaminase, proteins and carcinoembryonic antigen in PE were 246.0 U/L (range, 89.8–421.9 U/L), 13.8 U/L (range, 1.8–24.0 U/L), 42.6 g/dl (range, 32.8–52.6 g/dl) and 2.17 mg/mL (range, 0.46–4.31 mg/mL), respectively. Parasite-specific IgG antibody in blood and parasite eggs in stool were both negative. No evidence of tuberculosis or malignancy was observed in pleural biopsy. Symptoms and abnormal pulmonary imaging were eliminated after glucocorticoid use.

Conclusions

IEPE is a diagnosis of exclusion. Patients with EPE without a clear cause should be asked to provided complete medical, surgical and drug-related histories. A thorough work-up is essential. Moreover, we recommend follow-up after the use of glucocorticoid until effusion resolves.

Trial registration

GYFYY. Registration No: GYFYY20150901221. Registered time: 1 September 2015. Date of enrolment of the first participant to the trial: 22 January 2016.

Left Ventricular Cavity Obliteration From Eosinophilic Myocarditis in a Patient With Classic Hodgkin Lymphoma

A 43-year-old female with a history of hypereosinophilia developed acutely decompensated heart failure. Prototypical features of eosinophilic myocarditis, including a distinctive left ventricular mass and severe mitral regurgitation, were identified on a transthoracic echocardiogram. The patient's eosinophilia was subsequently attributed to Hodgkin lymphoma, and chemotherapy resolved her heart failure symptoms. (Level of Difficulty: Intermediate.).

Eosinophilic esophagitis, gastroenteritis, and colitis in a patient with prior parasite exposure

Eosinophilic gastrointestinal disorders (EGID) comprise a spectrum of inflammatory diseases that can affect any segment of the gastrointestinal tract. The pathogenesis of these conditions is complex; differentiating between primary and secondary forms of these disorders can be clinically challenging. We report a case of primary EGID in a patient with remote parasite exposure, whose symptoms were initially attributed to irritable bowel syndrome. Endoscopy revealed the rare finding of EGID involving the entire gastrointestinal tract; symptoms improved with an elimination diet. This case raises the possibility of a link between prior parasite exposure and development of EGID, and underscores the necessity of exploring alternative diagnoses in patients with presumed IBS who present with severe symptoms.

Rare manifestation of hypereosinophilic syndrome: Diffuse-type hair loss with massive perifollicular eosinophils

A 46-year-old woman consulted our hospital with diffuse alopecia and blood eosinophilia. Histological examination of the scalp revealed dense eosinophilic infiltration around the hair follicles and in the surrounding subcutis. Oral corticosteroid was effective to reduce hair loss and blood eosinophilia, but these conditions immediately relapsed after ending treatment. In addition to alopecia, she had diarrhea and colitis showing histological findings of dense eosinophilic infiltrations in the submucosa. We diagnosed hypereosinophilic syndrome based on hypereosinophilia of blood and tissue with clinical symptoms of alopecia and diarrhea. We suppose diffuse alopecia showing massive eosinophilic infiltration around the hair follicle is a rare symptom of hypereosinophilic syndrome.

[Differential diagnosis of hypereosinophilia]

Eosinophilia is defined as an elevated absolute number of eosinophilic leukocytes in peripheral blood or tissue. Its absolute number also defines the grade of eosinophilia. The main causes are allergic (including drug side effects) and infectious triggers but malignant and autoimmune diseases can also result in eosinophilia. Severe eosinophilia with the number of eosinophils >5000/µl are mostly caused by myeloproliferative disorders, eosinophilic granulomatosis with polyangiitis or during tissue migration in parasitic tissue infections. Hypereosinophilic syndrome is defined as eosinophilia with >1500 eosinophils/µl and a duration of more than 6 months by exclusion of parasitic infections, allergies or other causes of tissue eosinophilia with end-organ damage. For the diagnosis of a persistent eosinophilia a detailed medical history and physical examination should be followed by early organ screening, infection diagnostics especially for helminth infections and hematological laboratory analyses including bone marrow investigations.

Hypereosinophilic syndrome complicated by severe vascular damage and gangrene

Hypereosinophilic syndrome (HES) is a complex multisystem disease characterized by sustained overproduction of eosinophils. A 40-year-old woman presented with digital ischemia and gangrene on her distal fingers and toes. We diagnosed HES on the basis of marked eosinophilia, accumulation of eosinophils in organs, and cutaneous eosinophilic vasculitis after having excluded all differential diagnoses. On digital subtraction angiography, occlusion of several arteries of both lower legs was noted. HES may be associated with severe vascular damage including gangrene. The occurrence of digital gangrene is a differential diagnostic challenge that should also include investigations of blood parameters, such as eosinophils.

Eosinophilic Granulomatosis with Polyangiitis: Experiences in Korean Patients

Eosinophilic granulomatosis with polyangiitis (EGPA) is one form of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Identical to what has been called Churg-Strauss syndrome, EGPA exhibits both allergic and vasculitis features. EGPA was first described as a syndrome consisting of asthma, fever, eosinophilia, and organ involvement including heart failure, neuropathy, and kidney damage, by Churg and Strauss in 1951. On the basis of the 2012 Chapel Hill Consensus Conferences Nomenclature of Vasculitis, EGPA comprises three typical allergic components, including asthma, peripheral eosinophilia, and eosinophil-rich granuloma of the respiratory tracts. EGPA has three clinical and histological stages. The first is an allergic stage composed of asthma and sinusitis, and the second is an eosinophilic stage characterised by peripheral hypereosinophilia and intra-organ infiltration of eosinophils. The last is a vasculitic stage, including necrotising inflammation of small vessels and end-organ damage. In this review, we describe the classification criteria for EGPA and recommendations for the evaluation and management of EGPA with conventional and newly suggested drugs for EGPA. Also, we discuss a variety of clinical aspects such as predictive values for prognosis and associations with other Th2-mediated diseases and hepatitis B virus.

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

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

Targeting eosinophils: severe asthma and beyond

Recent research in the field of bronchial asthma has mainly focused on eosinophilic disease phenotype. Several trials proved the efficacy and safety profile of eosinophils and interleukin (IL)-5 targeting molecules, currently approved for severe asthma and available on the market. They include mepolizumab and reslizumab, IL-5 blocking molecules, and benralizumab, targeting the IL-5 receptor and eliciting a NK cell-mediated antibody-dependent cellular cytotoxicity against eosinophils. Eosinophilic inflammation represents the common pathophysiological background of several conditions, providing the rationale for the use of the same biologics beyond asthma. Although with different evidence grade, from clinical trials to case reports, anti-IL-5 biologics have been investigated in eosinophilic granulomatosis with polyangitis, allergic bronchopulmonary aspergillosis, chronic eosinophilic pneumonia, nasal polyposis, hypereosinophilic syndrome, and eosinophilic esophagitis. However, non-negligible differences between asthma and other eosinophilic diseases, particularly in eosinophils homing (blood and/or tissues), target organs and thus clinical features, probably account for the different response to the same drug in different clinical conditions and highlights the need for tailoring the therapeutic approach by modulating the drug dose and/or by combination therapy with multiple drugs. The optimal safety and tolerability profile of anti-IL-5 drugs warrants further and larger experimental and real-life investigations, which are needed especially in the field of non-asthma eosinophilic diseases. This review aims at summarizing the rationale for the use of biologics in eosinophilic diseases and their mechanisms of action. The current efficacy and safety evidence about eosinophils and IL-5 targeting molecules in asthma and in eosinophilic conditions beyond bronchi is also discussed.

Could hypereosinophilia at diagnosis estimate the current activity or predict relapse in systemic immunosuppressive drug-naïve patients with eosinophilic granulomatosis with polyangiitis?

In this study, we investigated whether hypereosinophilia (peripheral eosinophil ≥ 1500/mm³) at diagnosis could estimate the increased current activity and predict the poor prognosis during follow-up in patients with eosinophilic granulomatosis with polyangiitis (EGPA). We retrospectively reviewed the medical records of 42 patients with EGPA and finally included 30 systemic immunosuppressive drug-naïve patients. We obtained clinical and laboratory data including clinical manifestations, Birmingham vasculitis activity score (BVAS), five-factor score (FFS) (2009), and routine laboratory results. Hypereosinophilia was defined as peripheral eosinophil ≥ 1500/mm³. We divided EGPA patients based on hypereosinophilia and compared variables between the two groups. The cumulative relapse-free survival rates were compared by the Kaplan-Meier survival analysis. Patients with hypereosinophilia more commonly exhibited cutaneous manifestation than those without (50.0% vs. 14.3%, P = 0.038), but there were no significant differences in BVAS and FFS (2009) at diagnosis. Patients with hypereosinophilia showed the higher median WBC (14,200.0/mm³ vs. 7940.0/mm³) and CRP (17.6 mg/L vs. 2.0 mg/L) at diagnosis than those without. During follow-up, patients with hypereosinophilia at diagnosis exhibited the similar cumulative relapse-free survival rate to those without (P = 0.393). Whereas, patients with FFS (2009) at diagnosis ≥ 2, which was a well-known predictor of the poor prognosis of EGPA, exhibited the lower cumulative relapse-free survival rate than those with FFS (2009) < 2 (P = 0.030). Hypereosinophilia at diagnosis could neither estimate the current activity nor predict relapse in systemic immunosuppressive drug-naïve patients with EGPA unlike theoretical assumption.

Concurrent bilateral juvenile temporal arteritis and hypereosinophilic syndrome: a case report and review of the literature

Most of temporal arteritis occurs in the older patient over 50 years old, and the histopathologic finding shows a granulomatous inflammation, so this called giant cell arteritis. However, the young patients also present with a nodular lesion in their temple, and juvenile temporal arteritis (JTA) should be considered as one of the differential diagnosis, although it is very rare. For both diagnosis and treatment of JTA, excisional biopsy is essential. The pathologic finding of the temporal artery shows panarteritis with lymphoeosinophilic infiltrates, but no giant cell or granulomatous lesion. JTA is a localized disease with low level of systemic inflammatory marker, so the symptom is usually relieved by excision of affected lesion. Peripheral blood eosinophilia present in some cases of JTA, but its relation with clinical course and prognosis is not yet been known. Herein, we report the case of a 24-year-old man diagnosed with concurrent JTA and hypereosinophilic syndrome. We also reviewed the literature of JTA focusing on the impact of combined peripheral eosinophilia on the course of the disease. Combined peripheral eosinophilia may increase the risk of recurrence of JTA after local treatment such as excision only.

Structural Basis of Interleukin-5 Inhibition by the Small Cyclic Peptide AF17121

Interleukin-5 (IL-5) is a T-helper cell of subtype 2 cytokine involved in many aspects of eosinophil life. Eosinophilic granulocytes play a pathogenic role in the progression of atopic diseases, such as allergy, asthma and atopic dermatitis and hypereosinophilic syndromes. Here, eosinophils upon activation degranulate leading to the release of proinflammatory proteins and mediators stored in intracellular vesicles termed granula thereby causing local inflammation, which when persisting leads to tissue damage and organ failure. As a key regulator of eosinophil function, IL-5 therefore presents a major pharmaceutical target and approaches to interfere with IL-5 receptor activation are of great interest. Here we present the structure of the IL-5 inhibiting peptide AF17121 bound to the extracellular domain of the IL-5 receptor IL-5Rα. The small 18mer cyclic peptide snugly fits into the wrench-like cleft of the IL-5 receptor, thereby blocking access of key residues for IL-5 binding. While AF17121 and IL-5 seemingly bind to a similar epitope at IL-5Rα, functional studies show that recognition and binding of both ligands differ. Using the structure data, peptide variants with improved IL-5 inhibition have been generated, which might present valuable starting points for superior peptide-based IL-5 antagonists.

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

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

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

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

Unravelling the NERDS syndrome

A 22-year-old man presented with symmetric polyarthritis, pruritus and deviation of angle of mouth to the right side since the last 7 years. His symptoms were persistent despite receiving ayurvedic medications and symptomatic therapy. Examination revealed dry skin, cutaneous nodules, xanthelasma, periarticular non-tender swellings, pitting oedema of hands and feet and lower motor neuron type right facial palsy. Haematological investigations revealed eosinophilia and skin biopsy had cutaneous eosinophilic infiltration. The constellation of above findings comprises the nodules, eosinophilia, rheumatism, dermatitis and swelling syndrome. It a rare syndrome with few reported cases in literature. The patient was started on oral corticosteroids which was subsequently tapered and methotrexate therapy. His polyarthritis and skin rashes resolved with therapy. He has been followed-up for 2 years and is presently asymptomatic for the last 1 year.

Severe Multi-Organ Failure and Hypereosinophilia: When to Call It "Idiopathic"?

The hypereosinophilic syndrome is a rare disease characterized by the association between high absolute eosinophil count and eosinophil-mediated organ damage. We describe a case of a 70-year-old male with an absolute eosinophil count of 2130 cells/µL. Clinical symptoms and signs included the following: severe asthenia, axonal sensitive motor neuropathy, basal pleural effusion with signs of hypoventilation on chest radiography, and gastrointestinal symptoms such as severe diarrhea, weight loss (-10 kg in 6 months), abdominal pain, and vomiting. On physical examination he had an urticarial dermatitis on his back, abdomen, and lower limbs. An extensive instrumental and laboratory diagnostic workup was performed. When all causes of primary and secondary hypereosinophilic syndrome were excluded, treatment with solumedrol infusion and oral prednisone was started, with a rapid recover of clinical symptoms and normalization of laboratory parameters. A complete remission of the laboratory and clinical findings was achieved after 2 months and maintained over 1-year follow-up.