Eosinophilic Tissue Infiltration Research Articles

S2412 A Case of Idiopathic Hypereosinophilic Syndrome Involving the Gastrointestinal Tract

Introduction: Hypereosinophilia (HE) is defined by an absolute eosinophil count greater than 1.5 k/mcL taken one month apart or by histologic confirmation of eosinophilic infiltration of the tissues. Hypereosinophilic syndrome (HES) occurs when HE causes organ damage. Complications from eosinophilic gastrointestinal (GI) disease include perforation, ischemic colitis, and portal vein thrombosis. Here we present a case of idiopathic HES involving multiple organs including the GI tract. Case Description/Methods: A 39-year-old male presented to the hospital with 3 weeks of burning epigastric pain and diarrhea associated with fever; chills; fatigue; shortness of breath, and macular rash to the lower extremities. This began days after initiating a 12-day prednisone taper starting at 20 mg twice daily for presumed insect bite reaction. Eosinophils were 6.0 k/mcL on admission. Skin biopsy performed on lower extremities showed diffuse eosinophilic infiltration without evidence of vasculitis. Bronchoscopy revealed eosinophilic infiltration (92% eosinophils) without infection. ANA, anti-dsDNA, SSA, SSB, scleroderma antibody, C3, C4, RF, IgM, IgE, urine histoplasma antigen, serum coccidioides antibody, and antiphospholipid antibodies were within normal limits. With eosinophilic tissue infiltration associated with organ dysfunction and absolute eosinophil count >1.5 k/mcL, the patient met criteria for HES. Two doses of intravenous methylprednisolone 125 mg were administered before starting oral prednisone 60 mg AM and 20 mg PM for 90 days. The patient’s epigastric pain, shortness of breath, and pruritus resolved. Eosinophilia levels trended down from 9.3 k/mcL to 0.4 k/mcL within 3 days. Discussion: While HES is primarily an immunological condition, it is important for physicians to be aware of eosinophilic manifestations of the GI tract. The patient’s severe epigastric pain and diarrhea were suggestive of eosinophilic gastroenteritis. He had skin and bronchial biopsies (Figure) along with peripheral eosinophilia and multiorgan involvement meeting criteria for idiopathic HES. Esophagogastroduodenoscopy and tissue sampling from the GI tract was not obtained as the patient responded well to treatment, hence adding an extra procedure wouldn't have altered the course of management. Early recognition of our patient’s symptoms led to a minimally invasive patient experience and a rapid response to therapy.Figure 1.: Biopsy of bronchial mucosa showing dense infiltration of eosinophils beneath the bronchial epithelium (greater than 50 per high power field). The granular pink cells are the eosinophils, largely on the left-hand side of the image (400X magnification, H&E stain).

Serum IL-5, POSTN and IL-33 levels in chronic rhinosinusitis with nasal polyposis correlate with clinical severity

BackgroundChronic rhinosinusitis (CRS) is a group of heterogeneous diseases characterized by epithelial inflammation and tissue eosinophilic infiltration. IL-5, POSTN, and IL-33 are important factors that act as chemoattractants for eosinophils, and a tissue-remodeling protein positively correlated with eosinophils in blood and mediators of eosinophilic infiltration. The aim of the study was to determine the expression of IL-5, POSTN and IL-33, at the gene and protein levels, in eosinophilic CRS with nasal polyps (CRSwNP) and without nasal polyps (CRSsNP), and to correlate this expression with clinical severity.Materials and methodsThe study included 40 CRSwNP patients and 53 CRSsNP patients and 40 control subjects. The expression of IL-5, POSTN and IL-33 mRNA was determined in sinonasal mucosal samples and in nasal polyp tissue by real-time PCR. Protein levels in the serum of CRSwNP patients were measured by ELISA. Computed tomography was evaluated according to Lund–Mackay scores, and visual analog scale scores were assessed.ResultsNP tissue demonstrated significantly higher IL-5 and POSTN mRNA expression than the sinonasal tissue in the CRSsNP and CRSwNP groups. CRS groups demonstrated elevated IL-33 mRNA expression in comparison to controls irrespective of the presence of NP. No correlation was found between IL-5, POSTN and IL-33 mRNA expression and disease severity. CRSwNP group demonstrated significantly higher serum IL-5, POSTN and IL-33 protein levels than controls, and this corresponds to disease severity.ConclusionSerum IL-5, POSTN and IL-33 levels may be important markers for classification of eosinophilic CRSwNP patients, along with disease severity.

Helminth infection modulates number and function of adipose tissue Tregs in high fat diet-induced obesity.

BackgroundEpidemiological and experimental studies have shown a protective effect of helminth infections in weight gain and against the development of metabolic dysfunctions in the host. However, the mechanisms Treg cells exert in the helminth-obesity interface has been poorly investigated. The present study aimed to verify the influence of Heligmosomoides polygyrus infection in early stages of high fat diet-induced obesity.Principal findingsThe presence of infection was able to prevent exacerbated weight gain in mice fed with high fat diet when compared to non-infected controls. In addition, infected animals displayed improved insulin sensitivity and decreased fat accumulation in the liver. Obesity-associated inflammation was reduced in the presence of infection, demonstrated by lower levels of leptin and resistin, lower infiltration of Th1 and Th17 cells in adipose tissue, higher expression of IL10 and adiponectin, increased infiltration of Th2 and eosinophils in adipose tissue of infected animals. Of note, the parasite infection was associated with increased Treg frequency in adipose tissue which showed higher expression of cell surface markers of function and activation, like LAP and CD134. The infection could also increase adipose Treg suppressor function in animals on high fat diet.ConclusionThese data suggest that H. polygyrus modulates adipose tissue Treg cells with implication for weight gain and metabolic syndrome.

The roles of eosinophils and interleukin-5 in the pathophysiology of chronic rhinosinusitis with nasal polyps.

Chronic rhinosinusitis with nasal polyps (CRSwNP) is generally associated with eosinophilic tissue infiltration linked to type 2 inflammation and characterized by elevated levels of interleukin (IL)-5 and other type 2 inflammatory mediators. Although distinct and overlapping contributions of eosinophils and IL-5 to CRSwNP pathology are still being explored, they are both known to play an important role in NP inflammation. Eosinophils secrete numerous type 2 inflammatory mediators including granule proteins, enzymes, cytokines, chemokines, growth factors, lipids, and oxidative products. IL-5 is critical for the differentiation, migration, activation, and survival of eosinophils but is also implicated in the biological functions of mast cells, basophils, innate lymphoid cells, B cells, and epithelial cells. Results from clinical trials of therapeutics that target type 2 inflammatory mediators (including but not limited to anti-IL-5, anti-immunoglobulin-E, and anti-IL-4/13) may provide further evidence of how eosinophils and IL-5 contribute to CRSwNP. Finally, the association between eosinophilia/elevated IL-5 and greater rates of NP recurrence after endoscopic sinus surgery (ESS) suggests that these mediators may have utility as biomarkers of NP recurrence in diagnosing and assessing the severity of CRSwNP. This review provides an overview of eosinophil and IL-5 biology and explores the literature regarding the role of these mediators in CRSwNP pathogenesis and NP recurrence following ESS. Based on current published evidence, we suggest that although eosinophils play a key role in CRSwNP pathophysiology, IL-5, a cytokine that activates these cells, also represents a pertinent and effective treatment target in patients with CRSwNP.

Clinical Evidence of Type 2 Inflammation in Non-allergic Rhinitis with Eosinophilia Syndrome: a Systematic Review.

Non-allergic rhinitis (NAR) includes different subtypes, among which NAR with eosinophilia syndrome (NARES) is the most important because of severity of symptoms and the high risk of comorbidities. Its pathophysiology is still object of debate, but a crucial role of chronic eosinophilic inflammation has been recognized. The aim of this review is to critically analyze the current evidence regarding the hypothesis that NARES may be considered a type 2 inflammatory disorder. The definition and diagnostic criteria for NARES are not universally shared and adopted, thus generating difficulties in reproducing the results. At present, there is extreme heterogeneity in sampling methods and disagreement in the cut-off of local eosinophilic count to determine a diagnosis of NARES. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) standard was applied to identify English-language experimental and clinical articles regarding NARES. The search was performed in April 2021. Twenty-six articles were included. Our data suggest a particular heterogeneity regarding sampling and specific cut-offs adopted for diagnosis of NARES and consensus should be reached. We suggest that eosinophil count should be reported as an absolute value for at least 10 observed rich fields in order to increase the level of standardization. Consensus among authors on this topic should be reached with particular attention to the cut-off for diagnosis. In the future, this limitation may be overcome by the identification of repeatable biomarkers to refine diagnosis and prognosis of NARES. Furthermore, our data strongly suggest that NARES have numerous similarities with clinical features of the most common type 2 diseases such as eosinophilic asthma and chronic rhinosinusitis with nasal polyps (CRSwNP): late onset, association with type 2 comorbidities, selective eosinophilic tissue infiltration, remarkable response to oral and intranasal corticosteroids, and progression in a type 2 CRSwNP.

Cardiac Involvement in Churg-Strauss Syndrome

Introduction: The Churg-Strauss syndrome is a very rare systemic disease affecting people between 40-60 years old. It is recognized by the combination of blood eosinophilia, eosinophilic tissue infiltration, extravascular fibrinoid necrotizing (allergic) epithelioid and eosinophilic granuloma formation, and disseminated necrotizing vasculitis occurring in asthmatic patients. The diagnosis is based on well-defined criteria. The relation between blood eosinophilia and heart disease is well recognized with very heterogeneous damage. Mortality is associated with the cardiac manifestation of CSS in 50% of case. We conducted the current study to determine the prevalence and clinical impact of cardiac involvement in CSS patients. Methods: This was a retrospective and descriptive study about 11 patients followed in the Department of Internal Medicine of CHU Mohamed VI for Churg Strauss syndrome between the year 2017 and 2021. Results: The average age of our patients was 50 years. The sex ratio was 0, 57. The main cardiovascular risk factors were age, male sex, diabetes and hypertension, with a history of rhinitis in two patients and thyroidectomy in one patient. The diagnosis of CHURG-STRAUSS was based on the diagnostic criteria established by the American College of Rheumatology. The echocardiography was the basic examination to objectify the cardiac involvement with the following results: detection of a pericardial effusion in 2 cases, dilated cardiomyopathy in one patient and severe alteration of the ventricular function in one patient. The extracardiac injuries were divided into renal and neurological injuries. Corticosteroid therapy with Endoxan was the cornerstone of the treatment, with non-specific treatment depending on the clinical presentation.

Transcriptomic and Lipidomic Profiles in Nasal Polyps of Glucocorticoid Responders and Non-Responders: Before and After Treatment.

Background: The pathogenesis of chronic rhinosinusitis with nasal polyps (CRSwNP) and mechanisms underlying different responses to systemic glucocorticoids (GC) remain unclear. The major aim of this study was to explore the transcriptomic and oxidative lipidomic signatures and the effects of GC in patients with different clinical responses. Methods: Nasal polyp biopsies were obtained before and after 14-day oral GC treatment from 16 patients with CRSwNP, and normal nasal mucosa specimens were collected from 12 control subjects. RNA sequencing and oxidative lipidomics were performed, and differential gene expression analysis was conducted in the Responder and Non-responder groups at baseline and after treatment. Results: In the Responder group, GC significantly improved clinical symptoms and reduced tissue eosinophil infiltration. Meanwhile, GC led to a pronounced transcriptomic reversion with robust suppression of inflammatory responses and abnormal metabolism of extracellular matrix, as well as restoration of cilia function. However, non-responders were mainly characterized by epithelial hyperplasia and keratinization, with much less transcriptomic improvement after GC treatment. Higher expression of type 2 inflammatory molecules (CCL13, IGHE, CCL18, CCL23, CCR3, and CLC) with lower levels of LACRT, PPDPFL, DES, C6, MUC5B, and SCGB3A1 were related to a stronger clinical response to GC. Besides decreased prostaglandins and increased leukotrienes, increased dysregulation in other oxylipid mediators derived from polyunsaturated fatty acids was determined in nasal polyps, which was ameliorated by GC treatment. Conclusion: Systemic GC exert anti-inflammatory effects, improve tissue remodeling, restore cilia function, and ameliorate dysregulation of oxylipid mediator pathway in CRSwNP. GC-responders exhibited different transcriptomic signatures from non-responders.

Kimura Disease with Colli Dextra Tumor Manifestation: A Case Report

Abstract Kimura disease (KD) is a rare chronic inflammatory disease characterized by a triad of painless head and subcutaneous neck masses with regional lymphadenopathy, tissue and serum eosinophil infiltration, and elevated serum immunoglobulin E (IgE). It is a benign condition of unknown aetiology that usually affects young Asian men.1,2 We report a case of a 19-year-old woman with a neck lump for the past 3 months said to be enlarged. A less characteristic manifestation with a rare prevalence, Kimura disease, can be considered a differential diagnosis in a colli tumour. In this case, it was established after histopathological biopsy. Treatment for Kimura disease is still under observation in several studies. The treatments that have been tested include surgery, radiotherapy, and administration of corticosteroids and immunosuppressants, or a combination. In this case, surgical therapy was initiated, followed by steroids and radiotherapy.

Эозинофильный гастрит у ребенка. Как заподозрить? Критерии диагностики

Objective of the Review: To analyze current data on eosinophilic lesions of the stomach in children with the analysis of a clinical case. Key points. Diseases of the gastrointestinal tract associated with primary tissue eosinophilia are a heterogeneous group of changes characterized by inflammation, with predominantly eosinophilic tissue infiltration in the absence of other known causes. Clinical manifestations of allergic inflammatory diseases of the gastrointestinal tract are most often nonspecific. Depending on the level of the lesion, eosinophils are distinguished: gastritis (EoG), enteritis, and colitis. In recent years, more and more attention of experts has been directed to research in this area, but so far there are no general epidemiological data on the prevalence of this pathology in the population, both adults and children. Conclusion. Currently, there are no clear morphological criteria for diagnosing eosinophilic lesions of the stomach, small and large intestine in children, and clinical manifestations, especially in young children, are nonspecific. When making a diagnosis of EoG, it is necessary to take into account a family allergic history, a set of laboratory diagnostic data (eosinophilia in a clinical blood test and a high level of total IgE) and a morphological study of a biopsy of the gastric mucosa. Keywords: children, eosinophilic gastritis, eosinophilia, tissue eosinophilia, food allergy.

Применение эозинофильно-нейтрофильного индекса ЭНИ и показателя степени интенсивности воспалительной инфильтрации для оценки воспалительного процесса при полипозном риносинусите

Introduction. Identification of the cellular composition of polyps in polypous rhinosinusitis (PRS) is important. In practice, to determine the quantitative indicators of the number and ratio of eosinophilic and neutrophilic leukocytes in polyp tissue, the eosinophil-neutrophil index (ENI) was introduced, which is equal to the ratio of the arithmetic mean number of eosinophils to the arithmetic mean number of neutrophils in 10 considered fields of view at a magnification of the microscope ×400, and the indicator degree of cellular inflammatory infiltration. Objective. To conduct a pathomorphological study of the tissue of resected nasal polyps with the determination of ENI parameters and the degree of cellular inflammatory infiltration in various PRS phenotypes and evaluate the possibility of using these indicators as predictors of PRS drug control. Materials and methods. We examined 292 people (126 men, 166 women), mean age 52.12±13.04 years, with bilateral PRS, which were divided into 4 phenotypic groups: I group: PRS without concomitant bronchial asthma (BA) and respiratory allergies; IIa group: PRS + allergic BA (aBA) and allergic rhinitis (AR); IIb group: PRS + AR without BA; III group: PRS + nonallergic BA (nBA). During pathological examination, polyps were divided into 3 histological types: «eosinophilic,» «neutrophilic,» and «mixed»; the ENI index was determined, 3 degrees of inflammatory infiltration were established: weak (I degree) when the arithmetic mean of eosinophils, lymphocytes, neutrophils, macrophages, histiocytes, and mast cells in 10 representative fields of view does not exceed 200 cells; moderate (II degree) when the arithmetic mean varies from 201 to 400 cells; and significant (III degree) where the arithmetic mean is > 400 cells. In the PRS+BA groups, the state of BA control was determined using the ACQ-7 (Asthma Control Questionnaire). An analysis of the dynamics of ENI indicators and the degree of inflammatory infiltration was carried out depending on the effectiveness of conservative therapy with topical glucocorticoids (GCs) during the observation period of 1 year. The patients were divided into 3 groups: group 1, patients with positive dynamics, with a decrease in the degree of nasal polyps; group 2, the severity of polyps remained at the same level; group 3, the prevalence of polyps was higher than a year ago. Results. In all phenotypes of PRS, the eosinophilic type of inflammation prevails. The minimum indicators of ENI (11 [6;16]) and the degree of inflammatory infiltration (1 [1; 1]) were in the PRS +AR group, the highest intensity of inflammation was found in the PRS+nBA group (2.03 [2; 2]). According to the cellular composition of polyps in group 1, eosinophilic polyps were 87%; neutrophilic, 8%; mixed type, 5%; in group 2a, 97% of eosinophilic and 3% of mixed type in the absence of neutrophilic polyps, in group 2b ORS + AR, eosinophilic polyps were detected in 100%; in group 3, eosinophilic 88%, neutrophilic 6%, and mixed polyps 6% were diagnosed. Changes in ENI parameters and the intensity of inflammatory infiltration depending on the effectiveness of conservative therapy were revealed. In the group with positive dynamics, there was a decrease in these two indicators after 6 months of using intranasal GCs, in the absence of dynamics during therapy there were no changes in these indicators, and with low drug control, their increase was noted, which after the next 12 months was manifested by aggressive growth of polyps. At the same time, a correlation was found between the increase in the magnitude of indicators of local inflammation of the tissue of nasal polyps with a deterioration in the degree of control of BA of any etiology and the absence of significant correlations between blood eosinophilia and the level of eosinophilic infiltration of polypous tissue. Conclusions. 1. During the pathological examination of the surgical material, it is necessary to establish the histological type of nasal polyps (eosinophilic, neutrophilic, and mixed) to determine the further tactics of treating patients with PRS. 2. Pathological determination of the density of the inflammatory infiltrate in the tissue of resected nasal polyps with the calculation of ENI in clinical practice is necessary to control the dynamics of the course of inflammation, predict the possibility of relapse, and adjust the treatment of patients with PRS. 3. Correlation analysis in patients with PRS did not reveal a significant relationship between the severity of tissue eosinophilic infiltration of polyp tissue and the level of eosinophils in the peripheral blood, so the determination of peripheral blood eosinophilia is not enough to characterize local inflammation in PRS. 4. A decrease in ENI and the degree of density of the inflammatory infiltrate in nasal polyps in dynamics indicates the effectiveness of the ongoing conservative therapy. 5. An increase in the intensity of inflammatory infiltration in the tissues of polyps is accompanied by a deterioration in the medical control of asthma in phenotypes of PRS in combination with aBA and nBA.

Recurrent abdominal pain, peritoneal effusion, and eosinophilia in a boy aged 17 years.

A boy, aged 17 years, was admitted again due to abdominal pain, diarrhea, and eosinophilia for 3 years, which worsened for 3 days. Three years ago, the boy suffered from abdominal pain and diarrhea after eating yogurt; color Doppler ultrasound showed a large amount of peritoneal effusion, and routine blood test, bone marrow cell morphology, and ascites histological examination showed a large number of eosinophils. Three days ago, he was admitted again due to abdominal pain and diarrhea. The gastrointestinal endoscopy showed eosinophil infiltration in the angle of stomach. The boy was diagnosed with eosinophilic gastrointestinal disease (eosinophilic gastroenteritis). He was improved after the treatment with glucocorticoids and dietary avoidance, and no recurrence was observed during the one-year follow-up. It is concluded that for children who attend the hospital due to gastrointestinal symptoms such as abdominal pain and diarrhea, if there is an increase in peripheral blood eosinophils, it is necessary to consider the possibility of eosinophilic gastrointestinal disease, and eosinophil infiltration and abnormal eosinophil count in gastrointestinal tissue based on endoscopic biopsy may be the key to diagnosis.

ANALYSIS OF TISSUE EOSINOPHILS IN THE STRUCTURE OF GASTRI C POLYPS

A study of the diagnostic value of tissue eosinophil infiltration in the structure of polyps of the human gastrointestinal tract and surrounding tissues was carried out. We investigated intestinal biopsies from 189 patients aged 40–90 years with polyps, cancer, metastases. This retrospective study allows us to note the possibility of using eosinophils in the development of criteria for early malignancy and a promising outcome of neoplasms in the mucous membrane. Eosinophils are important players in intercellular interactions within the polyp structure and the tissues around it. The complete absence of eosinophils in the tissue of malignant polyps indicates the malignancy of the neoplasm. We revealed relationship between apoptosis and eosinophilic infiltration; both of them affect the outcome and prognosis of polyp development. Apoptosis induction by eosinophils and programmed cambium necrosis in tumor progression need to be further researched.

Response to mepolizumab according to disease manifestations in patients with eosinophilic granulomatosis with polyangiitis

BackgroundEosinophilic granulomatosis with polyangiitis (EGPA) is a relapsing disease with frequent glucocorticoid dependence. Mepolizumab has been demonstrated to reduce flares and spare glucocorticoids (GC). However, EGPA is a heterogeneous condition and the effects of mepolizumab on specific disease manifestations has not been completely delimitated. ObjectivesTo analyse the impact of mepolizumab on manifestations derived from small-vessel vasculitis, ENT (ear, nose and throat) symptoms, asthma, eosinophilic tissue infiltration and anti-neutrophil cytoplasmic antibody (ANCA) status in a single-centre cohort of EGPA patients. MethodsMedical charts of EGPA patients treated with mepolizumab were retrospectively reviewed by the authors to describe demographics, clinical characteristics, steroid dose at the initiation of mepolizumab and during follow-up, flares, disease activity, damage accrual and laboratory results. Results and conclusionsAmong 56 patients with EGPA regularly controlled at our department, 11 patients were treated with mepolizumab because of corticodependence and unsatisfactory disease control. The mean time of treatment was 38 months (range: 3-66 months). Patients with persistent symptoms improved their asthma control, but 3 of them persisted with recurrent ENT symptoms in spite of treatment with mepolizumab. None of the patients developed vasculitic manifestations (cutaneous, neurological, gastrointestinal, renal) during treatment. All patients achieved a Birmingham Vasculitis Activity Score (BVAS) of 0 points at 12 months or earlier. In general, patients reduced the number of flares, which tended to be milder, and all related to asthma or ENT manifestations. The improvement in disease activity allowed notable glucocorticoid tapering.

POS0121 RESPONSE OF EOSINOPHILIC GRANULOMATOSIS WITH POLYANGIITIS TO MEPOLIZUMAB ACCORDING TO DISEASE MANIFESTATIONS. A SINGLE CENTRE EXPERIENCE

Background:Eosinophilic granulomatosis with polyangiitis (EGPA) is a relapsing disease with frequent glucocorticoid (GC) dependence. Mepolizumab (MEPO) has been demonstrated to reduce flares and spare GC. However, EGPA is a heterogeneous disease and the effects of MEPO on specific disease manifestations has not been completely delimitated.Objectives:To analyze the impact of MEPO on manifestations derived from small-vessel vasculitis, ENT symptoms, asthma, eosinophilic tissue infiltration and ANCA status in a single-centre cohort of EGPA patients.Methods:Medical chart of EGPA patients treated with MEPO were reviewed to describe demographics, clinical characteristics, steroid dose at the initiation of MEPO and during follow-up, flares, disease activity, damage accrual and laboratory results.Results:Among 52 EGPA patients regularly controlled in our department, 11 patients were treated with MEPO. MEPO was prescribed when a) patients required prednisone (PDN) at ≥ 7.5 mg/d to maintain stability, or b) when maintained with < 7.5mg/d, presented at least 4 exacerbations/year requiring an increase in PDN dose. 6 were males and 5 females, with a mean age of 54 years at MEPO initiation. Baseline characteristics of the patients and course under treatment are presented in Table 1. ENT involvement, followed by asthma and eosinophil-related tissue-infiltration (ETI) were the most common symptoms when prescribing MEPO. Regarding treatment, patients received MEPO at 100-300mg SC monthly. The definition of flare was the same used in the MIRRA trial1. The mean time of treatment with MEPO was 34 months. All patients achieved a BVAS score of 0 points at 12 months or earlier. In general, patients reduced the number of flares, which tended to be milder, and all related to asthma or ENT manifestations. All improved their asthma control, but 3 of them persisted with recurrent ENT symptoms in spite of treatment with MEPO. None of them had vasculitic manifestations (cutaneous, neurological, gastrointestinal, renal) manifestations during treatment. All patients were able to tapper their PDN dose to ≤5 mg/day or less, except 3 patients. Of the 3 patients who required ≥5mg/d, 1 had severe asthma, but diminished the previous PDN dose (22.5 mg/d pre-MEPO, 10 mg/d currently) and the yearly rate of flares (8.2 pre-MEPO, 0.64 under-MEPO). The other one notably improved his asthma, but had ENT symptoms that responded unsatisfactorily to MEPO and required a maintenance PDN dose of 7.5 mg/d. The last one, improved her asthma control and was able to begin PDN tapering, but persisted with ENT symptoms. Regarding damage accrual, 6 patients remained stable during treatment, and 5 worsened. Two of three ANCA positive patients remained positive in spite of treatment.Table 1.Baseline characteristics at diagnosisAt mepolizumab initiationAfter mepolizumab (last follow-up)Age, median (range) years49 (23-67)54 (35-69)-Male/Female, n (%)6/5 (54.5%/45.5%)--BVAS, median (range)11 (2-20)2 (0-6)0FFS, value (n, %)1 (1, 9.1%)--VDI, mean (range)-1.7 (0-5)2.3 (0-5)Asthma, n (%)11 (100%)3 (27.3%)0 (0%)ENT, n (%)10 (90%)4 (36.4%)3 (27.3%)SVV, n (%)4 (36.4%)0 (0%)0 (0%)ETI signs/symptoms, n (%)7 (63.6%)2 (18.2%)0 (0%)Constitutional symptoms, n (%)4 (36.4%)0 (0%)0 (0%)Eosinophils, mean (range) cells x1095500 (600-8850)240 (0-600)55 (0-200)ANCA positivity (IIF)7 (77.8%)32Anti-MPO titers, mean (range)286 (93-740)88 (3-739)7 (3-37)Yearly rate of flares-1,750.51Immunosuppressants, n-31Prednisone dose, mg/d (range)8 (7.5-25)11.4 (5-22.5)5.125 (0-10)Conclusion:MEPO was effective for the treatment of patients with EGPA, with a reduction in the number and severity of flares and a decrease in PDN doses. A worse response of ENT involvement was observed. No vasculitic flares were observed in spite of GC reduction. Mepolizumab did not prevent damage accrual during the treatment period.

Rates of Thrombotic Events in Hypereosinophilic Syndrome and the Effect of Molecular Aberrations in Thrombotic Risk

Background: Idiopathic hypereosinophilia and hypereosinophilic syndrome (HES) comprise a rare, heterogeneous group of hematologic disorders characterized by the overproduction of eosinophils leading to tissue eosinophilic infiltration and damage. Hypereosinophilia can be primary - due to a clonal or malignant process - or secondary to a non-clonal process. Primary eosinophilia can be accompanied by clonal markers, such as in myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRA/B, FGFR1 or PCM1-JAK2, genetic mutations or chromosomal abnormalities leading to a diagnosis of chronic eosinophilic leukemia. Without easily identifiable clonal markers, a diagnosis of idiopathic HES is made after secondary causes are excluded. Thrombotic complications in clonal eosinophilic disorders have been described in case reports but the prevalence of thrombosis has not been extensively studied. We hypothesized that HES is associated with an increased thrombotic risk compared to the general population. Additionally, given the known increased thrombotic risk in patients with clonal hematopoiesis of indeterminate potential, we also hypothesized that the risk of thrombosis is greatest in HES patients with evidence of an underlying clonal process. Methods: Using an institutional database, we retrospectively analyzed 44 patients with HES who had undergone molecular testing with a DNA based next generation sequencing (NGS) assay (Heme SnapShot) and an RNA based NGS assay (Heme fusion) as part of their work up for HES at Massachusetts General Hospital from 2016 to 2020. Patients with secondary eosinophilia were excluded. We used Fisher's exact test to compare rates of thrombotic events or death between patients with and without molecular aberration. Relative risk and corresponding 95% CI was estimated by fitting a log-binomial regression model. Results: Among the 44 patients analyzed, 16 (36.4%) had a molecular aberration detected on NGS. Of the patients with molecular aberrations detected, 4 (25%) had PGFRA, PGFRB, or FGFR1 fusions. Other pathogenic mutations were as follows - 1 (6.3%) JAK2 mutation, 3 (18.8%) TET2, 1 (6.3%) DNMT3A and 9 (56.4%) had mutations in other genes. White blood cell count, absolute eosinophil count, hematocrit, platelet count, tryptase and vitamin B12 levels at diagnosis of HES were similar between the two groups. After a median follow-up time of 29 months (IQR 19.3, 52), 9 (20.5%) of all HES patients had a thrombotic event after diagnosis of HES (4 venous and 5 arterial) with a median time to first thrombotic event of 14.0 months (IQR 3.5, 28.0). HES patients with a molecular aberration had increased number of thrombotic events compared to HES patients with no molecular aberrations, 37.5% versus 10.7% respectively (p = 0.053, risk ratio 3.5, 95% CI 1.01 - 12.12). Three patients with molecular aberrations died versus 1 patient with no molecular aberrations (p = 0.129, risk ratio 5.25, 95% CI 0.59 - 46.36). Among patients with at least 12 months of follow-up (n = 40, 14 with and 26 without molecular aberrations), the one-year cumulative incidence of thrombotic events was 42.9% in patients with molecular aberrations vs 11.5% without (p = 0.044, RR 3.7 95% CI 1.2-12.0). HES patients who had thrombotic events had an increased risk of death compared to those without thrombotic events (p = 0.0226, RR 11.7, 95% CI 1.8 - 75.2). Conclusions: Thrombotic complications are common in the current study of patients with HES and are associated with an increased risk of death. Although our patient cohort was small, presence of molecular aberrations had increased rates of thrombotic events and mortality, suggesting an area of further study including possible therapeutic trials. Figure 1 Disclosures Brunner: Takeda: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; AstraZeneca: Research Funding; Forty-Seven Inc: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Al-Samkari:Argenx: Consultancy; Amgen: Research Funding; Dova: Consultancy, Research Funding; Agios: Consultancy, Research Funding; Rigel: Consultancy. Rosovsky:Bristol-Myers Squibb, Janssen: Research Funding; Bristol-Myers Squibb, Dova, Janssen, Portola: Consultancy. Fathi:PTC Therapeutics: Consultancy; Takeda: Consultancy; TrovaGene: Consultancy; Amgen: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Astellas: Consultancy; Novartis: Consultancy; NewLink Genetics: Consultancy, Honoraria; Daiichi Sankyo: Consultancy; Forty Seven: Consultancy; Jazz: Consultancy, Honoraria; Kite: Consultancy, Honoraria; Trillium: Consultancy; Seattle Genetics: Consultancy, Research Funding; Pfizer: Consultancy; Kura: Consultancy; Boston Biomedical: Consultancy; Blue Print Oncology: Consultancy; AbbVie: Consultancy; Agios: Consultancy, Research Funding; Amphivena: Consultancy, Honoraria. Weitzman:Abbvie: Consultancy. Hobbs:Incyte: Research Funding; Bayer: Research Funding; Novartis: Honoraria; Celgene/BMS: Honoraria; Merck: Research Funding; Constellation: Honoraria, Research Funding; Jazz: Honoraria.

Benralizumab for severe DRESS in two COVID-19 patients

Drug rash with eosinophilia and systemic symptoms (DRESS) is a rare severe hypersensitivity reaction that clinically manifests with exanthema, facial edema, enlarged lymph nodes, fever, and organ damage at variable degrees.1 Eosinophil expansion in blood is a hallmark of DRESS, and eosinophil tissue infiltration a main contributor to the observed organ damage and dysfunction.2 Although high-dose systemic glucocorticoids have not been evaluated in randomized clinical trials, they are currently the first-line therapy for DRESS with organ involvement.

Mepolizumab 100 mg in severe asthmatic patients with EGPA in remission phase

Eosinophilic granulomatosis with polyangiitis (EGPA) and severe eosinophilic asthma share some pathophysiological key features related to the vascular and tissue eosinophilic infiltration and the cytokine cascade it mediates.1,2 Given the consistent reduction in blood eosinophils and their pathogenic effects in patients with severe asthma treated with mepolizumab at the dose of 100 mg/4 wk, the same drug has been explored in patients with EGPA.1 The US Food and Drug Administration recently approved mepolizumab 300 mg/4 wk for EGPA.

Abstract 4507: TransConTM IL-2 β/γ: a novel long-acting prodrug of receptor-biased IL-2 designed for improved pharmocokinetics and optimal activation of T cells for the treatment of cancer

Abstract Background: Recombinant Interleukin-2 (IL-2, aldesleukin) is an approved immunotherapy for metastatic melanoma and renal cell carcinoma. However, treatment with IL-2 can induce severe side effects, such as vascular leak syndrome (VLS) and eosinophilic infiltration of cardiac and pulmonary tissues. IL-2 promotes the survival, proliferation and anti-tumor functions of CD8+ cytotoxic T cells, CD4+ effector T cells and natural killer cells, which mostly express the dimeric IL-2Rβγ receptor with low IL-2Rα levels. However, IL-2 also potently activates IL-2Rα+ immunosuppressive regulatory T cells as well as IL-2Rα+ eosinophils, type 2 innate lymphoid cells and endothelial cells, which may promote VLS. Aldesleukin is rapidly cleared with elimination T1/2 of 85 minutes requiring thrice daily dosing and resulting in large fluctuations in serum exposure, likely contributing to its toxicity. Thus, IL-2 has two critical drawbacks for cancer immunotherapy: 1) potent activation of undesired cells types expressing IL-2Rα and 2) high Cmax with rapid clearance. Methods: We developed TransCon (transient conjugation) IL-2 β/γ, a novel sustained release prodrug of a receptor-biased IL-2 (IL-2 β/γ) to optimally address each of these drawbacks. First, to block IL-2Rα binding yet retain IL-2Rβγ activity, we created IL2 β/γ by permanently attaching a small PEG moiety to an engineered cysteine placed at the IL-2Rα binding site. Second, to improve PK properties, we attached the receptor-biased IL-2 β/γ to a TransCon PEG carrier via a TransCon linker, shielding bioactivity and creating a prodrug. Under physiological conditions, TransCon IL-2 β/γ was designed for sustained release of the bioactive IL-2 β/γ from the PEG carrier, aiming for a much lower Cmax and longer effective half-life of released IL-2 β/γ compared to aldesleukin. Results: In binding and cell-based functional assays, free IL-2 β/γ demonstrated desirable IL-2 receptor selectivity maintaining IL-2Rβγ potency while losing IL2Rα potency. In vitro, TransCon IL-2 β/γ showed expected slow-release kinetics, supporting a half-life in humans of 2-3 days. In mouse tumor models, TransCon IL2 β/γ promoted CD8 and NK cell proliferation and activation. In cynomolgus monkeys, a single dose of TransCon IL-2 β/γ was well tolerated and induced a more robust CD8+ T cell and NK cell expansion relative to CD4+ T cells or eosinophils as compared to daily aldesleukin treatment. Consistent with these observations, TransCon IL-2 β/γ induced lower levels of systemic inflammatory cytokines and endothelial activity biomarkers when compared to aldesleukin. Summary: The data presented here provide evidence that TransCon IL-2 β/γ may promote anti-tumor immune effector function with improved tolerability. TransCon IL-2 β/γ was designed as a novel long-acting, receptor-biased IL-2 prodrug that has the potential to overcome the challenges of existing IL-2 treatments. Citation Format: David Brian Rosen, Burkhardt Laufer, Thomas Knappe, Meike Schnabel, Diana Begaliew, Joachim Zettler, Mathias Krusch, Ana Bernhard, Stefan Heinig, Valentino Konjik, Thomas Wegge, Vibeke Breinholt, Mohammad Tabrizi, Kennett Sprogoe, Juha Punnonen. TransConTM IL-2 β/γ: a novel long-acting prodrug of receptor-biased IL-2 designed for improved pharmocokinetics and optimal activation of T cells for the treatment of cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4507.

Microneedle-Mediated Allergen-Specific Immunotherapy for the Treatment of Airway Allergy in Mice.

Subcutaneous allergen-specific immunotherapy (SCIT) qualifies as a promising approach for the permanent cure of IgE-mediated airway allergies, which can often manifest into allergic rhinitis and other allergic respiratory diseases. SCIT entails repeated administration of a high allergen dose into the subcutaneous (sc) region using a hypodermic needle for many (3-5) years, which is inconvenient and painful and reduces patient compliance. To overcome these limitations, we hypothesized that microneedles (MNs), which are minimally invasive and painless, could provide a novel approach for allergen desensitization by depositing the allergen into the superficial layers of the skin. To test this hypothesis, we compared MNs and SCIT for allergen desensitization in a mouse model of ovalbumin (Ova)-induced airway allergy. Mice were first made allergic to Ova and then treated with MNs coated with Ova (with or without CpG as an adjuvant) or via SCIT-Ova + alum (subcutaneous Ova + alum injections) for comparison. Treatment with coated MNs significantly induced Ova-specific serum IgG antibodies in a manner comparable to SCIT-Ova + alum-treated group. To test the efficacy against allergen challenge, treated mice were challenged with Ova via the nasal route. Coated MNs with Ova and CpG (MN-Ova + CpG) considerably suppressed the airway inflammation in allergic mice, evidenced by downregulation of proinflammatory cytokines (IL-5 and IL-13), upregulation of anti-inflammatory cytokine IL-10, and activation of Ova-specific immune response in bronchoalveolar (BAL) fluid. The therapeutic capacity of MN-based allergy treatment was further validated by the reduction in eosinophil and mast cell infiltration in the lung tissues of mice treated with MN-Ova + CpG, and low deposition of mucus inside their lung bronchioles. Overall, coated MNs ameliorated the symptoms of airway allergy in mice similar to SCIT and could provide a novel means of painless allergen-specific immunotherapy.

Using Eosinophil Biomarkers From Rectal Epithelial Samples to Diagnose Food Protein-induced Proctocolitis: A Pilot Study.

The gold standard diagnostic procedure for food protein-induced proctocolitis (FPIP) requires flexible sigmoidoscopy (FS). To date there is no validated, noninvasive test to confirm FPIP diagnosis. Eosinophil-derived neurotoxin (EDN), a product of eosinophil (EOS) degranulation, has been shown to correlate with eosinophil infiltration in other tissues. Our objective was to compare EDN concentrations in rectal epithelial samples from infants with FPIP with those from a control population. Children who underwent routine FS at Arnold Palmer Hospital for Children were enrolled in an IRB-approved, prospective, open-label pilot study between July 2017 and May 2019. We obtained rectal epithelial samples via: rectal swab, cytology brushing through FS, and rectal biopsy through FS. We then measured EDN levels in the samples and compared levels found in infants with FPIP against levels found in the control group. FPIP was defined as more than 60 EOS per 10 high-power fields (HPF) in rectal epithelial tissue obtained via rectosigmoid biopsy. Twenty-four patients were enrolled. The control group (n = 13) included patients with normal histopathology (84% boys, mean age 19 months, SD 6 months) and the FPIP group (n = 11) included patients with FPIP confirmed via biopsy (45% boys, mean age 6.9 months, SD 9 months). EDN concentration was significantly higher in the FPIP group than in the control group, for 2 sampling methods: rectal biopsy (183.6 ± 114.6 vs 76.6 ± 71.0 μg/mL; P = 0.010) and rectal swab (66.2 ± 64.8 vs 20.4 ± 22.2 μg/mL; P = 0.025). EDN concentrations measured from rectal swab and rectal biopsy samples is elevated and may be a useful tool to screen for FPIP in children.