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

Tumefactive eosinophil-rich non-granulomatous small vessel vasculitis in the cerebrum in a patient with idiopathic hypereosinophilic syndrome

The definite diagnosis of central nervous system vasculitis requires pathological verification by biopsy or surgical resection of the lesion, which may not always be feasible. A 74-year-old woman with a history of allergic rhinitis, but not asthma, presented with slowly progressive left hemiparesis. Magnetic resonance imaging of the head revealed a heterogeneously enhancing mass involving the right internal capsule and corona radiata. Histological examination of the resected specimen revealed eosinophil-rich non-granulomatous small vessel vasculitis with no neutrophil infiltration or foci of microbial infection. Epstein-Barr virus in situ hybridization was negative, and polymerase chain reaction tests for both T-cell receptor gamma and immunoglobulin heavy-chain variable region genes did not show rearrangements, excluding the possibility of lymphoma and lymphoproliferative disorders. Blood hypereosinophilia and elevated erythrocyte sedimentation rate were observed; however, anti-neutrophil cytoplasmic antibodies were not detected. A biopsy of the erythema in the hips and thighs revealed perivasculitis with eosinophilic infiltration within the dermis. Chest computed tomography revealed multiple small nodules in the lungs. Her symptoms, aside from hemiparesis, disappeared after corticosteroid administration. The clinicopathological features were similar to eosinophilic granulomatosis with polyangiitis but did not meet its current classification criteria and definition. This patient is the first reported case of idiopathic eosinophilic vasculitis or idiopathic hypereosinophilic syndrome-associated vasculitis affecting the small vessels in the brain. Further clinicopathological studies enrolling similar cases are necessary to establish the disease concept and unravel the underlying pathogenesis.

X-linked hyper IgM syndrome with severe eosinophilia: a case report and review of the literature

Background

Hyper IgM syndromes (HIGMS) are a group of rare primary immunodeficiency disorders. There are limited reports about HIGMS combined with severe eosinophilia.

Case presentation

In this report, we described a 2-year-old boy with chronic cough and symptoms of hypoxia. Lung computed tomography (CT) scan showed that diffuse ground-glass changes and eosinophils in peripheral blood increased significantly. Subsequent tests revealed a notable decrease in serum IgG and IgA. The lymphocyte subgroup classification was basically normal. Pneumocystis jirovecii were detected from the bronchoalveolar lavage fluid (BALF) of the patient by metagenomic next-generation sequencing (mNGS). After treatments of caspofungin combined with sulfamethoxazole, intravenous immunoglobulin (IVIG) replacement and anti-inflammatory steroid, the clinical symptoms and pulmonary imaging noticeably improved. The absolute eosinophil count (AEC) also returned to normal range. X-linked hyper IgM syndrome was confirmed by gene test. Two months after the diagnosis, the patient underwent allogeneic stem cell transplantation (HSCT) and has recovered well.

Conclusions

Children with HIGMS are prone to opportunistic infections such as Pneumocystis jirovecii pneumonia (PJP). Diffuse interstitial lung disease and hypoglobulinemia in a young child predict the diagnosis of a primary immunodeficiency (PID). mNGS has obvious advantages for obtaining etiological diagnosis of children with PIDs. Severe eosinophilia is rarely reported in this kind of PIDs. Considering literature review and the corresponding reaction to steroid, we proposed that eosinophilia in HIGMS might be related to infections. Steroid therapy can quickly relieve eosinophilia but is easy to rebound if the reduction is too fast. Once the diagnosis of HIGMS is confirmed, the earlier the HSCT, the better the prognosis.

Pancarditis as the Clinical Presentation of Eosinophilic Granulomatosis with Polyangiitis: A Multimodality Approach to Diagnosis

Eosinophilic pancarditis (EP) is a rare, often unrecognized condition caused by endomyocardial infiltration of eosinophil granulocytes (referred as eosinophilic myocarditis, EM) associated with pericardial involvement. EM has a variable clinical presentation, ranging from asymptomatic cases to acute cardiogenic shock requiring mechanical circulatory support (MCS) or chronic restrictive cardiomyopathy at high risk of progression to dilated cardiomyopathy (DCM). EP is associated with high in-hospital mortality, particularly when associated to endomyocardial thrombosis, coronary arteries vasculitis or severe left ventricular systolic dysfunction. To date, there is a lack of consensus about the optimal diagnostic algorithm and clinical management of patients with biopsy-proven EP. The differential diagnosis includes hypersensitivity myocarditis, eosinophil granulomatosis with polyangiitis (EGPA), hypereosinophilic syndrome, parasitic infections, pregnancy-related hypereosinophilia, malignancies, drug overdose (particularly clozapine) and Omenn syndrome (OMIM 603554). To our knowledge, we report the first case of pancarditis associated to eosinophilic granulomatosis with polyangiitis (EGPA) with negative anti-neutrophil cytoplasmic antibodies (ANCA). Treatment with steroids and azathioprine was promptly started. Six months later, the patient developed a relapse: treatment with subcutaneous mepolizumab was added on the top of standard therapy, with prompt disease activity remission. This case highlights the role of a multimodality approach for the diagnosis of cardiac involvement associated to systemic immune disorders.

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.

From DREAM to REALITI-A and beyond: Mepolizumab for the treatment of eosinophil-driven diseases

Effective treatment of inflammatory diseases is often challenging owing to their heterogeneous pathophysiology. Understanding of the underlying disease mechanisms is improving and it is now clear that eosinophils play a complex pathophysiological role in a broad range of type 2 inflammatory diseases. Standard of care for these conditions often still includes oral corticosteroids (OCS) and/or cytotoxic immune therapies, which are associated with debilitating side effects. Selective, biological eosinophil‐reducing agents provide treatment options that improve clinical symptoms associated with eosinophilic inflammation and reduce OCS use. Mepolizumab is a humanized monoclonal antibody that binds to and neutralizes interleukin‐5, the major cytokine involved in eosinophil proliferation, activation, and survival. Mepolizumab is approved for the treatment of severe eosinophilic asthma, eosinophilic granulomatosis with polyangiitis and hypereosinophilic syndrome. Additionally, the efficacy of add‐on mepolizumab has been observed in patients with severe chronic rhinosinusitis with nasal polyposis and chronic obstructive pulmonary disease with an eosinophilic phenotype. Here, we review the development, approval, and real‐world effectiveness of mepolizumab for the treatment of patients with severe eosinophilic asthma, from the DREAM to REALITI‐A studies, and describe how knowledge from this journey extended to the use of mepolizumab and other biologics across a broad spectrum of eosinophilic diseases.

Pediatric Acute Lymphoblastic Leukemia With Hypereosinophilia and IDH2 Gene Mutation: A Case Report and Literature Review

Eosinophilia is a rare presentation of acute lymphoblastic leukemia (ALL) within the pediatric population. In this report, we present a patient with pre-B ALL and eosinophilia in the setting of an isocitrate dehydrogenase-2 gene mutation. These mutations have been described in patients with acute myeloid leukemia but in very few patients with ALL.

OUP accepted manuscript

Background

This review summarizes the case studies of PCM1-JAK2 fusion tyrosine kinase gene-related neoplasia. Recommended treatment includes JAK2 inhibitors and hematologic stem cell transplantation (HSCT), although the small number of patients has limited study of their efficacy. Herein, we present all available cases in the current searchable literature with their demographics, diagnoses, treatments, and outcomes.

Methods

PubMed, ScienceDirect, Publons, the Cochrane Library, and Google were searched with the following terms: PCM1-JAK2, ruxolitinib and myeloid/lymphoid.

Results

Sixty-six patients (mean age = 50, 77% male) had an initial diagnosis of myeloproliferative neoplasm (MPN) in 40, acute leukemia in 21 and T-cell cutaneous lymphoma in 5. Thirty-five patients (53%) had completed 5-year follow-up. The 5-year survival for the MPN, acute myelogenous leukemia (AML), acute lymphocytic leukemia, and lymphoma groups are 62.7, 14.9%, 40.0%, and 100%, respectively. Too few patients have been treated with ruxolitinib to draw conclusions regarding its effect on survival while the 5-year survival for MPN patients with or without HSCT was 80.2% (40.3%-94.8%) versus 51.5% (22.3%-74.6%), respectively. The T-cell cutaneous lymphoma patients have all survived at least 7 years.

Conclusion

This rare condition may be increasingly detected with wider use of genomics. Ruxolitinib can yield hematologic and molecular remissions. However, HSCT is, at this time, the only potentially curative treatment. Useful prognostic markers are needed to determine appropriate timing for HSCT in patients with MPN. Patients presenting with acute leukemia have a poor prognosis.

Biallelic TERT variant leads to Hoyeraal-Hreidarsson syndrome with additional dyskeratosis congenita findings

Short telomere syndromes constitute a heterogeneous group of clinical conditions characterized by short telomeres and impaired telomerase activity due to pathogenic variants in the essential telomerase components. Dyskeratosis congenita (DC) is a rare, multisystemic telomere biology disorder characterized by abnormal skin pigmentation, oral leukoplakia and nail dysplasia along with various somatic findings. Hoyeraal-Hreidarsson syndrome (HHS) is generally an autosomal recessively inherited subgroup showing growth retardation, microcephaly, cerebellar hypoplasia and severe immunodeficiency. We here report on a consanguineous family from Turkey, in which a missense variant in the reverse transcriptase domain of the TERT gene segregated with short telomere lengths and was associated with full-blown short telomere syndrome phenotype in the index; and heterogeneous adult-onset manifestations in heterozygous individuals.

Pulmonary Eosinophils at the Center of the Allergic Space-Time Continuum

Eosinophils are typically a minority population of circulating granulocytes being released from the bone-marrow as terminally differentiated cells. Besides their function in the defense against parasites and in promoting allergic airway inflammation, regulatory functions have now been attributed to eosinophils in various organs. Although eosinophils are involved in the inflammatory response to allergens, it remains unclear whether they are drivers of the asthma pathology or merely recruited effector cells. Recent findings highlight the homeostatic and pro-resolving capacity of eosinophils and raise the question at what point in time their function is regulated. Similarly, eosinophils from different physical locations display phenotypic and functional diversity. However, it remains unclear whether eosinophil plasticity remains as they develop and travel from the bone marrow to the tissue, in homeostasis or during inflammation. In the tissue, eosinophils of different ages and origin along the inflammatory trajectory may exhibit functional diversity as circumstances change. Herein, we outline the inflammatory time line of allergic airway inflammation from acute, late, adaptive to chronic processes. We summarize the function of the eosinophils in regards to their resident localization and time of recruitment to the lung, in all stages of the inflammatory response. In all, we argue that immunological differences in eosinophils are a function of time and space as the allergic inflammatory response is initiated and resolved.

Renal Involvement as Rare Acute Tubulointerstitial Nephritis in a Patient with Eosinophilic Disorder Treated with Early Add-on Administration of Mepolizumab

A 39-year-old man presented with peripheral eosinophilia, pulmonary eosinophilic infiltrate, and renal failure due to acute tubulointerstitial nephritis (TIN). He had experienced childhood asthma and was negative for anti-neutrophil cytoplasmic antibody (ANCA). He was tentatively diagnosed with ANCA-negative eosinophilic granulomatous polyangiitis (EGPA) or idiopathic hypereosinophilic syndrome (HES). Renal involvement of isolated TIN with eosinophil infiltration is rare in EGPA and HES and does not seem to have a good prognosis in the literature. However, his condition improved well with corticosteroids and mepolizumab. The revised classification of EGPA based on the etiology should dictate the proper treatment in suspected EGPA patients with nonsystemic vasculitis.

Case Report: Evolution of KIT D816V-Positive Systemic Mastocytosis to Myeloid Neoplasm With PDGFRA Rearrangement Responsive to Imatinib

Systemic mastocytosis (SM) is a rare neoplasm resulting from extracutaneous infiltration of clonal mast cells (MC). The clinical features of SM are very heterogenous and treatment should be highly individualized. Up to 40% of all SM cases can be associated with another hematological neoplasm, most frequently myeloproliferative neoplasms. Here, we present a patient with indolent SM who subsequently developed a myeloid neoplasm with PDGFRA rearrangement with complete response to low-dose imatinib. The 63-year-old patient presented with eosinophilia and elevated serum tryptase level. Bone marrow analysis revealed aberrant MCs in aggregates co-expressing CD2/CD25 and KIT D816V mutation (0.01%), and the FIP1L1-PDGFRA fusion gene was not identified. In the absence of ‘B’ and ‘C’ findings, we diagnosed an indolent form of SM. For 2 years after the diagnosis, the absolute eosinophil count progressively increased. Bone marrow evaluation showed myeloid hyperplasia and the FIP1L1-PDGFRA fusion gene was detected. Thus, the diagnosis of myeloid neoplasm with PDGFRA rearrangement was established. The patient was treated with imatinib 100 mg daily and rapidly obtained a complete molecular remission. The clinical, biological, and therapeutic aspects of SM might be challenging, especially when another associated hematological disease is diagnosed. Little is known about the underlying molecular and immunological mechanisms that can promote one entity prevailing over the other one. Currently, the preferred concept of SM pathogenesis is a multimutated neoplasm in which KIT mutations represent a “phenotype modifier” toward SM. Our patient showed an evolution from KIT mutated indolent SM to a myeloid neoplasm with PDGFRA rearrangement; when the eosinophilic component expanded, a regression of the MC counterpart was observed. In conclusion, extensive clinical monitoring associated with molecular testing is essential to better define these rare diseases and consequently their prognosis and treatment.

Eosinophilia characterized by a rare CCT6B mutation and responsive to tyrosine kinase inhibition: Case report and literature review

Hypereosinophilic syndrome is a rare disorder arising from neoplastic, or idiopathic causes. The availability of NGS panels has increasingly identified rare mutations as underlying pathogenic events and have led to reclassification of cases of idiopathic hypereosinophilic syndrome as chronic eosinophilic leukemia(CEL). In this report, we describe a case of a young man with hypereosinophilia whose disease initially did not fit the WHO criteria for CEL but harbored a rare mutation in CCT6B gene. We report our experience in successfully treating this patient with multiple tyrosine kinase inhibitors and provide literature review of this rare entity including potential treatment strategies.

Nanopore sequencing for the screening of myeloid and lymphoid neoplasms with eosinophilia and rearrangement of PDGFRα, PDGFRβ, FGFR1 or PCM1-JAK2

Eosinophilia represents a group of diseases with heterogeneous pathobiology and clinical phenotypes. Among the alterations found in primary Eosinophilia, gene fusions involving PDGFRα, PDGFRβ, FGFR1 or JAK2 represent the biomarkers of WHO-defined "myeloid and lymphoid neoplasms with eosinophilia". The heterogeneous nature of genomic aberrations and the promiscuity of fusion partners, may limit the diagnostic accuracy of current cytogenetics approaches. To address such technical challenges, we exploited a nanopore-based sequencing assay to screen patients with primary Eosinophilia. The comprehensive sequencing approach described here enables the identification of genomic fusion in 60 h, starting from DNA purified from whole blood.

Is strongyloidiasis currently autochthonous in Croatia? A retrospective study

BACKGROUND

Autochthonous human infections with Strongyloides stercoralis have been well documented in many European regions. By exploring patients' data, we aimed to find elements for its current endemicity in Croatia.

METHODS

This retrospective descriptive study analysed epidemiological and clinical data of patients treated for strongyloidiasis from January 2010 to May 2019 at a teaching hospital in Zagreb, Croatia. The diagnosis was made by direct methods using light microscopy and/or serology.

RESULTS

Among 65 patients with strongyloidiasis, 60% were men, and 78.5% were 50-79 y of age. The sensitivity of the examination of three stool samples after concentration, saline provocation and serology was 26.2, 80.7 and 86.2%, respectively. Clinical presentation included asymptomatic patients with eosinophilia (41.5%), chronic symptomatic infection (33.8%), acute infection (18.5%) and hyperinfection (6.2%). Twenty patients (30.8%) were immunosuppressed; among four of whom developed hyperinfection, two died. Initially 71.7% of patients were treated with albendazole and 13.3% with ivermectin, with an equal parasitological cure rate (72.2% and 75%; p=0.09). In 11 patients, acute infection was autochthonous in its origin.

CONCLUSIONS

Strongyloidiasis is currently endemic in Croatia and immunosuppressed travellers to this region should be advised to take precautions. Patients undergoing immunosuppression and organ donors from Croatia should be screened.

Persistent eosinophilia and associated organ involvement in Thai patients with systemic sclerosis: Data from the Siriraj scleroderma cohort

Objectives

This study aims to investigate the prevalence of persistent eosinophilia and associated organ complications in Thai patients with systemic sclerosis (SSc).

Patients and methods

This post-hoc study included 107 adult patients (23 males, 84 females; mean age: 50.4±11.6 years; range, 18 to 79 years) diagnosed with SSc between November 2013 and June 2017. Eosinophilia was defined as an absolute eosinophil count of >500/μL or a percentage count of >7%. Eosinophil levels collected at every visit over one year were categorized as persistently high (PH), persistently low (PL), high-to-low (HL), low-to-high (LH), or variable levels (VL). The study compared variables between PH and non-PH (PL+HL+LH+VL) groups. The patients with baseline eosinophilia were also identified and compared with the non-eosinophilia group.

Results

The median disease duration was 3.2 years. Of the patients, 79.4% had diffuse cutaneous SSc and 76.7% had anti-Scl-70 positivity. A total of 11.2%, 66.4%, 1.9%, 8.4%, and 12.1% of the patients were categorized into the PH, PL, HL, LH, and VL groups, respectively. Compared to non-PH groups, the PH group had a higher prevalence of anti-centromere antibody (ACA), higher baseline percent predicted total lung capacity, and lower baseline C-reactive protein and creatine phosphokinase (p<0.05 for all). The ACA positivity (odds ratio [OR]: 18.5; 95% confidence interval [CI]: 1.64-208.46) was associated with PH. The patients with baseline eosinophilia (17.8%) had a higher prevalence of non-specific interstitial pneumonia with periodic eosinophilia at the time of diagnosis (100% vs. 6.5%, p<0.0001; OR: 4.667; 95% CI: 1.712-12.724).

Conclusion

The PH was seldom (11%) in patients with SSc compared to periodic eosinophilia, which was more prevalent (18%). It may be related to ACA positivity and better pulmonary outcomes, whereas periodic eosinophilia may involve interstitial lung disease.

Comprehensive characterization of central BCL-2 family members in aberrant eosinophils and their impact on therapeutic strategies

Purpose

Hypereosinophilia represents a heterogenous group of severe medical conditions characterized by elevated numbers of eosinophil granulocytes in peripheral blood, bone marrow or tissue. Treatment options for hypereosinophilia remain limited despite recent approaches including IL-5-targeted monoclonal antibodies and tyrosine kinase inhibitors.

Methods

To understand aberrant survival patterns and options for pharmacologic intervention, we characterized BCL-2-regulated apoptosis signaling by testing for BCL-2 family expression levels as well as pharmacologic inhibition using primary patient samples from diverse subtypes of hypereosinophilia (hypereosinophilic syndrome n = 18, chronic eosinophilic leukemia not otherwise specified n = 9, lymphocyte-variant hypereosinophilia n = 2, myeloproliferative neoplasm with eosinophilia n = 2, eosinophilic granulomatosis with polyangiitis n = 11, reactive eosinophilia n = 3).

Results

Contrary to published literature, we found no difference in the levels of the lncRNA Morrbid and its target BIM. Yet, we identified a near complete loss of expression of pro-apoptotic PUMA as well as a reduction in anti-apoptotic BCL-2. Accordingly, BCL-2 inhibition using venetoclax failed to achieve cell death induction in eosinophil granulocytes and bone marrow mononuclear cells from patients with hypereosinophilia. In contrast, MCL1 inhibition using S63845 specifically decreased the viability of bone marrow progenitor cells in patients with hypereosinophilia. In patients diagnosed with Chronic Eosinophilic Leukemia (CEL-NOS) or Myeloid and Lymphatic Neoplasia with hypereosinophilia (MLN-Eo) repression of survival was specifically powerful.

Conclusion

Our study shows that MCL1 inhibition might be a promising therapeutic option for hypereosinophilia patients specifically for CEL-NOS and MLN-Eo.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-021-03827-9.

Hypereosinophilia with cerebral venous sinus thrombosis and intracerebral hemorrhage: A case report and review of the literature

BACKGROUND

Hypereosinophilia (HE) is defined as a peripheral blood eosinophil count of > 1.5 × 10⁹/L and may be associated with tissue damage. The clinical presentations of HE vary; however, myocardial fibrosis and thrombosis can threaten the lives of patients with sustained eosinophilia. Cerebral venous sinus thrombosis (CVST) in the setting of eosinophil-related diseases has seldom been reported. Here, we review the literature on HE with CVST to increase knowledge and encourage early diagnosis.

CASE SUMMARY

A previously healthy 41-year-old man was admitted to hospital with diarrhea and abdominal pain. He was treated with antibiotics for suspected acute colitis. Three days later, he experienced headache and vomiting. Brain computed tomography (CT) revealed thrombosis of the left jugular vein to the left transverse sinus vein. Platelet (PLT) count decreased to 60 × 10¹²/L, and absolute eosinophil count (AEC) increased to 2.41 × 10⁹/L. He was treated with low-molecular-weight heparin. PLT count progressively decreased to 14 × 10⁹/L, and we terminated anticoagulation and performed PLT transfusion. Six days after admission, he complained of a worsening headache. Brain CT revealed right temporal lobe and left centrum semiovale intracerebral hemorrhage, and AEC increased to 7.65 × 10⁹/L. We used prednisolone for HE. The level of consciousness decreased, so emergency hematoma removal and decompressive craniectomy for right cerebral hemorrhage were performed. The patient was alert 2 d after surgery. He was treated with anticoagulation again 2 wk after surgery. Corticosteroids were gradually tapered without any symptomatic recurrence or abnormal laboratory findings.

CONCLUSION

HE can induce CVST, and we need to focus on eosinophil counts in patients with CVST.

Hypereosinophilia: a rare cause of stroke and multiorgan dysfunction

Eosinophilia can occur due to a plethora of allergic, infective, neoplastic and idiopathic conditions. Hypereosinophilic syndrome (HES) is characterised by sustained eosinophilia and multiorgan dysfunction in the absence of an identifiable cause. It may range from a self-limiting condition to a rapidly progressive life-threatening disorder, of which ischaemic stroke is a rare presentation. Such episodes can rarely be the presenting manifestation, and may develop before any other laboratory abnormality or organ involvement. We report a case of HES presented with multiorgan (neurological and renal) involvement, managed successfully with steroids and cytoreductive therapy. High initial absolute eosinophil count can be a clue to the diagnosis and early treatment should be initiated in such patients, to prevent fatal outcomes.

Inborn errors of immunity with eosinophilia

Monogenic diseases of the immune system, also known as inborn errors of immunity (IEIs), are caused by single-gene mutations and result in immune deficiency and dysregulation. More than 400 monogenic diseases have been described to date, and this number is rapidly expanding. The increasing availability of next-generation sequencing is now facilitating the diagnosis of IEIs. It is known that IEIs can predispose a person to not only infectious diseases but also cancer and immune disorders, such as inflammatory, autoimmune, and atopic diseases. IEIs with eosinophilia and atopic diseases can occur in several disorders. IEIs with eosinophilia have provided insights into human immunity and the pathogenesis of allergic diseases. Eosinophilia is not a rare finding in clinical practice, and it often poses problems in terms of etiologic research and differential diagnoses. Secondary eosinophilia is the most common form. The main underlying conditions are infectious diseases such as parasitic infections, allergic disorders, drug reactions, and of course IEIs. In clinical settings, the recognition of IEIs in the context of an allergic phenotype with eosinophilia is critical for prompt diagnosis and appropriate treatment aimed at modulating pathophysiological mechanisms and improving clinical symptoms.

A novel activating JAK1 mutation in chronic eosinophilic leukemia

Hypereosinophilia (HE) has been defined as persistent eosinophilia >1.5 × 109/L; it is broadly divided into primary HE (clonal or neoplastic; HEN), secondary/reactive HE (HER), or HE of undetermined significance (HEUS) when no cause is identified. The use of myeloid next-generation sequencing (NGS) panels has led to the detection of several mutations in patients previously diagnosed with HEUS, reassigning some patients to the category of HEN, specifically the World Health Organization category of chronic eosinophilic leukemia, not otherwise specified (CEL, NOS). Here, we describe a novel somatic JAK1 pseudokinase domain mutation (R629_S632delinsSA) in a patient with HE that had initially been characterized as a variant of uncertain significance. We performed functional studies that demonstrated that this mutation results in growth factor independence of Ba/F3 cells in vitro and activation of the JAK-STAT pathway. These effects were abrogated by the JAK1/JAK2 inhibitor ruxolitinib. R629_S632delinsSA is the first known somatic mutation in JAK1 linked to a clonal eosinophilic neoplasm, and highlights the importance of the JAK-STAT pathway in eosinophil survival.

Chronic Eosinophilic Leukaemia Associated with JAK2 Exon 13 Insertion/Deletion Mutations

Chronic eosinophilic leukaemia, not otherwise specified (CEL, NOS), is a diagnosis of exclusion made in cases in which there is clonal eosinophilia but an absence of genetic aberrations that define other disease subtypes. There is a need for further characterization of these cases in order to inform risk stratification and management. The importance of JAK2 mutations in myeloproliferative neoplasms (MPN) as a whole is well established, although their role specifically in eosinophilic disorders is less clear, with only a minority of cases demonstrating JAK2 abnormalities. Here, we report 2 cases with an exon 13 insertion-deletion (indel) mutation in JAK2: one with CEL-NOS and the second with an unspecified eosinophilic disorder. JAK2 indels were not detected in a screen of suspected MPN cases (n = 592) without eosinophilia that tested negative for common MPN driver mutations. Our findings thus provide further evidence for a specific association between this rare mutation and clonal eosinophilic disorders.

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.

Prominent Role of Type 2 Immunity in Skin Diseases-Beyond Atopic Dermatitis

Type 2 immunity, illustrated by T helper 2 lymphocytes (Th2) and downstream cytokines (IL-4, IL-13, IL-31) as well as group 2 innate lymphoid cells (ILC2), is important in host defense and wound healing.¹ The hallmark of type 2 inflammation is eosinophilia and/or high IgE counts and is best recognized in atopic diathesis. Persistent eosinophilia, such as seen in hypereosinophilic syndromes, leads to fibrosis and hence therapeutic Type 2 inhibition in fibrotic diseases is of high interest. Furthermore, as demonstrated in cutaneous T cell lymphoma, advanced disease is characterized by Th1 to Th2 switch allowing cancer progression and immunosuppression. Development of targeted monoclonal antibodies against IL-4Rα (eg, dupilumab) led to a paradigm shift for the treatment of atopic dermatitis (AD) and stimulated research to better understand the role of Type 2 inflammation in other skin conditions. In this review, we summarize up to date knowledge on the role of Type 2 inflammation in skin diseases other than AD and highlight whether the use of Type 2 targeted therapies has been documented or is being investigated in clinical trials. This manuscript reviews the role of Type 2 inflammation in dermatitis, neurodermatitis, IgE-mediated dermatoses (eg, bullous pemphigoid, chronic spontaneous urticaria), sclerodermoid conditions and skin neoplasms.

Organ-Specific Hypereosinophilic Syndrome Presenting as Eosinophilic Gastroenteritis

Gastrointestinal (GI) diseases have a substantial impact on the population health and healthcare resources of the United States. They constitute billions of dollars in expenditure and millions of office and hospital visits. With advancing diagnostic and treatment modalities, rare diseases are increasingly recognized and managed. However, after close to 80 years since the first description, eosinophilic GI disorders (EGID) are still uncommon, and only around 300 cases have been reported to date. Hypereosinophilic syndrome (HES) is well studied, but there are still no guidelines to direct management. We report the case of a 56-year-old female who presented with gastroenteritis and a persistent eosinophil count above 7 x 10⁹/L. Imaging was suggestive of bowel wall thickening, and endoscopy revealed normal-appearing mucosa. However, histologic examination revealed eosinophilic infiltration of the GI tract. She was diagnosed with HES and treated with oral prednisone with remarkable improvement of her symptoms.

T-Cell Lymphoblastic Lymphoma Arising in the Setting of Myeloid/Lymphoid Neoplasms with Eosinophilia: LMO2 Immunohistochemistry as a Potentially Useful Diagnostic Marker

Simple Summary

Rarely, T-lymphoblastic lymphoma (T-LBL) may develop in the setting of myeloid/lymphoid neoplasms with eosinophilia. Given important therapeutic implications, it is crucial to identify T-LBL arising in this particular context. LIM domain only 2 (LMO2) is known to be overexpressed in almost all sporadic T-LBL and not in immature TdT-positive T-cells in the thymus and in indolent T-lymphoblastic proliferations. We retrospectively evaluated the clinical, morphological, immunohistochemical and molecular features of 11 cases of T-LBL occurring in the setting of myeloid/lymphoid neoplasms with eosinophilia and investigated the immunohistochemical expression of LMO2 in this setting of T-LBL. Interestingly, 9/11 cases were LMO2 negative, with only 2 cases showing partial expression. In our study, we would suggest that LMO2 immunostaining, as part of the diagnostic panel for T-LBL, may represent a useful marker to identify T-LBL developing in the context of myeloid/lymphoid neoplasms with eosinophilia.

Abstract

Background: Rarely, T-lymphoblastic lymphoma (T-LBL) may develop in the setting of myeloid/lymphoid neoplasms with eosinophilia (M/LNs-Eo), a group of diseases with gene fusion resulting in overexpression of an aberrant tyrosine kinase or cytokine receptor. The correct identification of this category has relevant therapeutic implications. LIM domain only 2 (LMO2) is overexpressed in most T-LBL, but not in immature TdT-positive T-cells in the thymus and in indolent T-lymphoblastic proliferations (iT-LBP). Methods and Results: We retrospectively evaluated 11 cases of T-LBL occurring in the context of M/LNs-Eo. Clinical, histological, immunohistochemical and molecular features were collected and LMO2 immunohistochemical staining was performed. The critical re-evaluation of these cases confirmed the diagnosis of T-LBL with morphological, immunohistochemical and molecular features consistent with T-LBL occurring in M/LNs-Eo. Interestingly, LMO2 immunohistochemical analysis was negative in 9/11 cases, whereas only 2 cases revealed a partial LMO2 expression with a moderate and low degree of intensity, respectively. Conclusions: LMO2 may represent a potentially useful marker to identify T-LBL developing in the context of M/LNs-Eo. In this setting, T-LBL shows LMO2 immunohistochemical profile overlapping with cortical thymocytes and iT-LBP, possibly reflecting different molecular patterns involved in the pathogenesis of T-LBL arising in the setting of M/LNs-Eo.

Systemic hypereosinophilic syndromes: when autoimmunity is Th2 mediated

PURPOSE OF REVIEW

Clinical conditions associated with hypereosinophilia represent a field of particular interest, taking into account the epidemiological impact of the different primary and secondary forms. In addition to a classical Th1 response, also Th2 cells can be involved in the pathogenesis of autoimmune diseases, among them eosinophilic forms such as eosinophilic granulomatosis with polyangiitis.

RECENT FINDINGS

In patients with severe asthma, recent evidence highlights the role of pathogenic autoantibodies against autologous eosinophil proteins (e.g. eosinophil peroxidase) suggest the role of autoimmune mechanisms, particularly in patients in which asthma is included in eosinophilic vasculitis with antineutrophilic autoantibody positivity. Is now evident that in addition to Th2 cells, also type 2 innate lymphoid cells and Th1/Th17 cells play a central role in the pathogenesis of hypereosinophilic syndrome.

SUMMARY

The definition of cellular and molecular mechanisms and the critical role of specific cytokines involved in the pathogenesis of hypereosinophilic syndrome open the way to new therapeutic strategies by using biological agents targeting these specific factors.

Detection of cryptogenic malignancies from metagenomic whole genome sequencing of body fluids

BACKGROUND

Metagenomic next-generation sequencing (mNGS) of body fluids is an emerging approach to identify occult pathogens in undiagnosed patients. We hypothesized that metagenomic testing can be simultaneously used to detect malignant neoplasms in addition to infectious pathogens.

METHODS

From two independent studies (n = 205), we used human data generated from a metagenomic sequencing pipeline to simultaneously screen for malignancies by copy number variation (CNV) detection. In the first case-control study, we analyzed body fluid samples (n = 124) from patients with a clinical diagnosis of either malignancy (positive cases, n = 65) or infection (negative controls, n = 59). In a second verification cohort, we analyzed a series of consecutive cases (n = 81) sent to cytology for malignancy workup that included malignant positives (n = 32), negatives (n = 18), or cases with an unclear gold standard (n = 31).

RESULTS

The overall CNV test sensitivity across all studies was 87% (55 of 63) in patients with malignancies confirmed by conventional cytology and/or flow cytometry testing and 68% (23 of 34) in patients who were ultimately diagnosed with cancer but negative by conventional testing. Specificity was 100% (95% CI 95-100%) with no false positives detected in 77 negative controls. In one example, a patient hospitalized with an unknown pulmonary illness had non-diagnostic lung biopsies, while CNVs implicating a malignancy were detectable from bronchoalveolar fluid.

CONCLUSIONS

Metagenomic sequencing of body fluids can be used to identify undetected malignant neoplasms through copy number variation detection. This study illustrates the potential clinical utility of a single metagenomic test to uncover the cause of undiagnosed acute illnesses due to cancer or infection using the same specimen.

A case of hypereosinophilia with digital ischaemia successfully treated with intravenous prostaglandin E1

In the therapeutic management of eosinophilic disorder, it is important to prevent hypereosinophilia (HE)-related organ damage even in the process of diagnosis. We describe here a unique clinical and histopathological findings of the patient with HE accompanied with digital ischaemia. Treatment with intravenous prostaglandin E1 was essential for digital ischaemia in our case while benralizumab, humanized monoclonal antibody against interleukin-5 receptorα, did not affect. Our case suggests an earlier intervention for digital ischaemia in the therapeutic management of eosiniphilic disorder.

FIP1L1-PDGFRA fusion gene in a patient with asthma and rhinitis

Eosinophilia in asthma or rhinitis is usually considered to be reactive to the allergic diseases. We report a 33-year-old man with asthma and rhinitis, and progressive hypereosinophilia. Fluorescence in situ hybridization analysis detected interstitial chromosomal deletion at 4q12 in cells of the bone marrow. The patient was diagnosed as myeloproliferative neoplasm with a FIP1L1-PDGFRA fusion gene, and successfully treated with the tyrosine kinase inhibitor, imatinib. Clonal expansion of eosinophils due to the FIP1L1-PDGFRA fusion gene could underlie refractory mechanisms in patients with bronchial asthma or allergic rhinitis.

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.

Non-Specific Binding, a Limitation of the Immunofluorescence Method to Study Macrophages In Situ

Advances in understanding tissue regenerative mechanisms require the characterization of in vivo macrophages as those play a fundamental role in this process. This characterization can be approached using the immuno-fluorescence method with widely studied and used pan-markers such as CD206 protein. This work investigated CD206 expression in an irradiated-muscle pig model using three different antibodies. Surprisingly, the expression pattern during immunodetection differed depending on the antibody origin and could give some false results. False results are rarely described in the literature, but this information is essential for scientists who need to characterize macrophages. In this context, we showed that in situ hybridization coupled with hybridization-chain-reaction detection (HCR) is an excellent alternative method to detect macrophages in situ.

Precision medicine in myeloid malignancies

Myeloid malignancies have always been at the forefront of an improved understanding of the molecular pathogenesis of cancer. In accordance, over the last years, basic research focusing on the aberrations underlying malignant transformation of myeloid cells has provided the basis for precision medicine approaches and subsequently has led to the development of powerful therapeutic strategies. In this review article, we will recapitulate what has happened since in the 1980s the use of all-trans retinoic acid (ATRA), as a first targeted cancer therapy, has changed one of the deadliest leukemia subtypes, acute promyelocytic leukemia (APL), into one that can be cured without classical chemotherapy today. Similarly, imatinib, the first molecularly designed cancer therapy, has revolutionized the management of chronic myeloid leukemia (CML). Thus, targeted treatment approaches have become the paradigm for myeloid malignancy, but many questions still remain unanswered, especially how identical mutations can be associated with different phenotypes. This might be linked to the impact of the cell of origin, gene-gene interactions, or the tumor microenvironment including the immune system. Continuous research in the field of myeloid neoplasia has started to unravel the molecular pathways that are not only crucial for initial treatment response, but also resistance of leukemia cells under therapy. Ongoing studies focusing on leukemia cell vulnerabilities do already point to novel (targetable) "Achilles heels" that can further improve myeloid cancer therapy.

Real-Life Experience of Monoclonal Antibody Treatments in Chronic Rhinosinusitis with Nasal Polyposis

INTRODUCTION

Few studies assess biologicals such as, omalizumab, mepolizumab, benralizumab, and dupilumab in patients suffering from chronic rhinosinusitis with nasal polyposis (CRSwNP). The reported success rate in these studies differ, and it remains uncertain if there are any biomarkers to predict successful therapy. Our aim was to analyze the therapeutic outcome in a real life setting and to identify predictive biomarkers for successful treatment.

METHODS

Data from patients with CRSwNP treated with a monoclonal antibody between November 2014 and January 2020 were analyzed retrospectively. Improvement in the polyp score and clinical symptoms like nasal obstruction, sense of smell, nasal discharge, and facial pain were evaluated. Other characteristics, including use of nasal or systemic steroids, comorbidities, previous history of sinus surgery, eosinophilia tissue, blood values (eosinophils, total immunoglobulin E, eosinophilic cationic protein, and interleukin 5), and allergic sensitization in serum were also investigated to identify possible predictive biomarkers.

RESULTS

Forty-eight treatments in 29 patients (m/f = 15/14) aged 27-70 years were reviewed. Treatments with mepolizumab showed the best success rates (78.9%), followed by omalizumab (50%) and benralizumab treatments (50%). However, a correlation between biomarkers and treatment success could not be found.

DISCUSSION/CONCLUSION

Treatment of CRSwNP with biologicals is a promising option for severe cases not responding to conventional therapy, including difficult-to-treat patients. Predictive biomarkers for a successful treatment could not be identified, but the reduction of eosinophilic cationic protein was linked with the response.

Eosinophilic pericardial effusion in a cat with complex systemic disease and associated peripheral eosinophilia

An 11-year-old domestic shorthair cat was referred for investigation of dry cough of 1-week duration and cardiomegaly. Echocardiography revealed pericardial effusion, and eosinophils were identified as the predominant cell type in fluid collected by pericardiocentesis. Thoracic computed tomography imaging and bronchoscopy were supportive of mild lower airway disease, while bronchoalveolar lavage confirmed eosinophilic inflammation and concurrent Mycoplasma felis infection. A few months after the initial presentation, there was clinical deterioration, and further investigation suggested intestinal lymphoma. It was hypothesized that pericardial effusion and lower airway inflammation were an early manifestation of hypereosinophilic syndrome, possibly as a paraneoplastic consequence of lymphoma.

Myeloid/Lymphoid Neoplasms Associated With Eosinophilia and Rearrangements of PDGFRA, PDGFRB, or FGFR1 or With PCM1-JAK2

OBJECTIVES

To summarize cases submitted to the 2019 Society for Hematopathology/European Association for Haematopathology Workshop under the category of myeloid/lymphoid neoplasms with eosinophilia and PDGFRA, PDGFRB, or FGFR1 or with PCM1-JAK2 rearrangements, focusing on recent updates and relevant practice findings.

METHODS

The cases were summarized according to their respective gene rearrangement to illustrate the spectrum of clinical, laboratory, and histopathology manifestations and to explore the appropriate molecular genetic tests.

RESULTS

Disease presentations were heterogeneous, including myeloproliferative neoplasms (MPNs), myelodysplastic syndromes (MDSs), MDS/MPN, acute myeloid leukemia, acute B- or T-lymphoblastic lymphoma/acute lymphoblastic lymphoma (ALL/LBL), or mixed-lineage neoplasms. Frequent extramedullary involvement occurred. Eosinophilia was common but not invariably present. With the advancement of RNA sequencing, cryptic rearrangements were recognized in genes other than PDGFRA. Additional somatic mutations were more frequent in the FGFR1-rearranged cases. Cases with B-ALL presentations differed from Philadelphia-like B-ALL by the presence of an underlying MPN. Cases with FLT3 and ABL1 rearrangements could be potential candidates for future inclusion in this category.

CONCLUSIONS

Accurate diagnosis and classification of this category of myeloid/lymphoid neoplasms has important therapeutic implications. With the large number of submitted cases, we expand our understanding of these rare neoplasms and improve our ability to diagnose these genetically defined disorders.

A case of hypereosinophilic syndrome with STAT5b N642H mutation

Hypereosinophilia is defined as persistent eosinophilia (>1.5 × 10⁹/L). Hypereosinophilic syndrome (HES) is a term used to describe a group of disorders characterized by sustained hypereosinophilia associated with end-organ damage. Based on underlying molecular mechanism of eosinophilia, there are different subtypes of HES. Diagnosis of HES subtype can be challenging, especially in the absence of overt lymphoid/myeloid neoplasms or discernable secondary causes. Long-term outpatient follow-up with periodic complete blood count and repeated bone marrow biopsy may be needed to monitor disease activity. Somatic signal transducer and activation transcription 5b (STAT5b) N642H mutation was recently found to be associated with myeloid neoplasms with eosinophilia. We report a case of HES who presented with pulmonary embolism and acute eosinophilic pneumonia, found to have recurrent STAT5b N642H mutation by next-generation sequencing, suggesting possible underlying myeloid neoplasm.

Molecular Pathogenesis and Treatment Perspectives for Hypereosinophilia and Hypereosinophilic Syndromes

Hypereosinophilia (HE) is a heterogeneous condition with a persistent elevated eosinophil count of >350/mm³, which is reported in various (inflammatory, allergic, infectious, or neoplastic) diseases with distinct pathophysiological pathways. HE may be associated with tissue or organ damage and, in this case, the disorder is classified as hypereosinophilic syndrome (HES). Different studies have allowed for the discovery of two major pathogenetic variants known as myeloid or lymphocytic HES. With the advent of molecular genetic analyses, such as T-cell receptor gene rearrangement assays and Next Generation Sequencing, it is possible to better characterize these syndromes and establish which patients will benefit from pharmacological targeted therapy. In this review, we highlight the molecular alterations that are involved in the pathogenesis of eosinophil disorders and revise possible therapeutic approaches, either implemented in clinical practice or currently under investigation in clinical trials.

Myeloid neoplasm with eosinophilia and rearrangement of platelet-derived growth factor receptor beta gene in children: Two case reports

BACKGROUND

Myeloid neoplasm (MN) with eosinophilia and rearrangement of platelet-derived growth factor receptor beta (PDGFRB) shows a good therapeutic response to imatinib in adults. MN is rarely found in children, and the efficacy of imatinib on pediatric patients remain unclear.

CASE SUMMARY

We report 2 pediatric cases diagnosed with MN with eosinophilia and PDGFRB rearrangement who were treated with imatinib. Case 1 was a 1-year-old girl admitted to the hospital because of “abdominal distension with hyperleukocytosis for 3 mo”. She had leukocytosis, anemia, and eosinophilia (the absolute eosinophil count (AEC) was 8960/μL), and her fluorescence in situ hybridization (FISH) test revealed that PDGFRB rearrangement was detected in 70% of 500 interphase cells. Case 2 was a 2-year-old girl admitted to the hospital because of “recurrent fever and rashes for 1 mo”. Her blood cell count showed an AEC of 3540/μL. The FISH test revealed that PDGFRB rearrangement was detected in 71% of 500 interphase cells. Both patients were diagnosed as MN with eosinophilia and PDGFRB rearrangement. Imatinib was added into their treatment regimen. As expected, complete hematologic remission was achieved after 1 mo of treatment, and symptoms disappeared.

CONCLUSION

Although MN with eosinophilia and PDGFRB rearrangement usually occurs in adults, it can be found in children. The therapeutic benefits of imatinib in these 2 pediatric patients were consistent with its reported effects in adult patients.

Hypereosinophilia with Hepatic Nodule Formation Caused by Ganoderma lucidum

A 61-year-old man who underwent surgery for rectal adenocarcinoma developed multiple hepatic nodules. The nodules were 1-3 cm without a capsular structure or contrast enhancement on computed tomography/magnetic resonance imaging, findings that were atypical for adenocarcinoma metastases. A biopsy showed the aggregation of eosinophils without larval bodies, ova, or granulomas. Laboratory tests showed a marked increase in eosinophils and a slight liver enzyme elevation. He had been taking the commercial herbal medicine Ganoderma lucidum for his liver function. After discontinuing G. lucidum, the eosinophil counts and liver enzyme levels rapidly resolved, and the nodules disappeared completely. This is a rare case of hypereosinophilia with hepatic nodules reactive to herbal medicine rather than a parasitic infection.

Mepolizumab in Hypereosinophilic Syndrome: A Systematic Review and Meta-analysis

We aimed to evaluate the efficacy and safety of mepolizumab (MEP) in the management of hypereosinophilic syndrome (HES). A systematic search was performed, and articles published until March 2021 were analyzed. The primary efficacy results evaluated were hospitalization rate related to HES, morbidity (new or worsening), relapses/failure, treatment-related adverse effects, prednisone dosage ≤10 mg/day for ≥8 weeks, and eosinophil count <600/μL for ≥8 weeks. A meta-analysis was conducted, when appropriate. Three randomized controlled trials (RCTs), with a total of 255 patients, were included. The studies contemplated the use of MEP 300 mg/SC or 750 mg/IV. According to the evaluation of the proposed outcomes, when relapse rates/therapeutic failures were assessed, there was a 26% reduction with MEP 300 mg/SC (RD=-0.26; 95% CI: -0.44 to -0.08; p=0.04) and 48% reduction with MEP 750 mg/IV (RD=-0.48; 95% CI: -0.67, -0.30; p<0.00001). For the outcomes, prednisone dosage ≤10 mg/day for ≥8 weeks was 48% (RD=0.48; 95% CI: 0.35 to 0.62; p<0.00001), and the eosinophil count <600/μL for ≥8 weeks was 51% (RD=0.51; 95% CI: 0.38 to 0.63; p<0.00001), both showed a reduction with MEP 300 mg/IV and 750 mg/IV. No statistically significant differences in treatment-related adverse effects outcomes were observed for either dosage (RD=0.09; 95% CI: -0.05 to 0.24; p=0.20; RD=0.09; 95% CI: -0.11 to 0.29; p=0.39). Despite the positive effects observed for the studied outcomes, the exact significance remains unclear.

Localized IgG4-related disease manifested on the tongue: a case report

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory condition that can affect multiple organs. IgG4-RD may show a variety of initial symptoms. In the oral mucosa, lesions present as inflammatory fibrosis with a large number of IgG4-positive plasma cells. Evaluating treatment is a well-known problem in IgG4-RD due to the absence of an established assessment system. There are difficulties in defining the severity of the disease, which is why treatment is primarily based on its clinical manifestations. We present a case report of localized IgG4-RD with ulcerative and proliferative manifestations on the tongue, which clinically mimicked oral squamous cell carcinoma. A tumor-like lesion on the tongue can indicate something else other than the malignant or reactive changes commonly found in the oral mucosa. Multiple differential diagnoses of these atypical oral lesions, including localized IgG4-RD, should be considered.

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.