Eosinophilia and thrombophilia in churg strauss syndrome: a clinical and pathogenetic overview

Ocular manifestations in ANCA-associated vasculitis: a comprehensive analysis from Chinese medical centers

INTRODUCTION

This study aimed to explore ocular manifestations in ANCA-associated vasculitis (AAV), focusing on granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA), and microscopic polyangiitis (MPA) and to examine the associations with laboratory parameters and other systemic manifestations.

METHODS

This retrospective study reviewed data from 533 AAV patients across two major Chinese medical centers from January 2016 to November 2023. Data including diagnosis, cranial manifestations of disease, ocular complications, and laboratory parameters were analyzed. Univariate and multivariable logistic regression analyses assessed associations across disease manifestations. Machine learning models were also utilized to predict the risk of retinal/eye involvement in AAV patients.

RESULTS

Among 533 patients (210 GPA, 217 MPA, 99 EGPA, and 7 unclassified AAV), ocular complications were observed in 20.64% of them, with a distribution of 36.67% in GPA, 7.37% in MPA, and 18.18% in EGPA. The most common ocular manifestations included scleritis and retro-orbital mass/dacryocystitis, which were notably prevalent in GPA patients. Retinal involvement was observed in 9.09% of EGPA cases. The machine learning models yielded that eosinophil percentage (EOS%), high-sensitivity C-reactive protein (hsCRP), and CD4 + T cell/CD8 + T cell ratio (T4/T8) can predict retinal involvement. Furthermore, the white blood cell, EOS%, APTT, IgA, hsCRP, PR3-ANCA, and T4/T8 can predict eye involvement.

CONCLUSION

Ocular manifestations are a prevalent complication across all forms of AAV. Predictive models developed through machine learning offer promising tools for early intervention and tailored patient care. This necessitates a multidisciplinary approach, integrating rheumatology and ophthalmology expertise for optimal patient outcomes.

Cardiovascular disease and thrombosis: Intersections with the immune system, inflammation, and the coagulation system

The coagulation and immune system, both essential physiological systems in the human body, are intricately interconnected and play a critical role in determining the overall health of patients. These systems collaborate via various shared regulatory pathways, such as the Tissue Factor (TF) Pathway. Immunological cells that express TF and generate pro-inflammatory cytokines have the ability to affect coagulation. Conversely, coagulation factors and processes have a reciprocal effect on immunological responses by stimulating immune cells and regulating their functions. These interconnected pathways play a role in both preserving well-being and contributing to a range of pathological disorders. The close relationship between blood clotting and inflammation in the development of vascular disease has become a central focus of clinical study. This research specifically examines the crucial elements of this interaction within the contexts of cardiovascular disease and acute coronary syndrome. Tissue factor, the primary trigger of the extrinsic coagulation pathway, has a crucial function by inducing a proinflammatory reaction through the activation of coagulation factors. This, in turn, initiates coagulation and subsequent cellular signalling pathways. Protease-activated receptors establish the molecular connection between coagulation and inflammation by interacting with activated clotting factors II, X, and VII. Thrombosis, a condition characterised by the formation of blood clots, is the most dreaded consequence of cardiovascular disorders and a leading cause of death globally. Consequently, it poses a significant challenge to healthcare systems. Antithrombotic treatments efficiently target platelets and the coagulation cascade, but they come with the inherent danger of causing bleeding. Furthermore, antithrombotics are unable to fully eliminate thrombotic events, highlighting a treatment deficiency caused by a third mechanism that has not yet been sufficiently addressed, namely inflammation. Understanding these connections may aid in the development of novel approaches to mitigate the harmful mutual exacerbation of inflammation and coagulation. Gaining a comprehensive understanding of the intricate interaction among these systems is crucial for the management of diseases and the creation of efficacious remedies. Through the examination of these prevalent regulatory systems, we can discover novel therapeutic approaches that specifically target these complex illnesses. This paper provides a thorough examination of the reciprocal relationship between the coagulation and immune systems, emphasising its importance in maintaining health and understanding disease processes. This review examines the interplay between inflammation and thrombosis and its role in the development of thrombotic disorders.

COVID-19 vaccine adverse events: Evaluating the pathophysiology with an emphasis on sulfur metabolism and endotheliopathy

In this narrative review, we assess the pathophysiology of severe adverse events that presented after vaccination with DNA and mRNA vaccines against COVID-19. The focus is on the perspective of an undersulfated and degraded glycocalyx, considering its impact on immunomodulation, inflammatory responses, coagulation and oxidative stress. The paper explores various factors that lead to glutathione and inorganic sulfate depletion and their subsequent effect on glycocalyx sulfation and other metabolites, including hormones. Components of COVID-19 vaccines, such as DNA and mRNA material, spike protein antigen and lipid nanoparticles, are involved in possible cytotoxic effects. The common thread connecting these adverse events is endotheliopathy or glycocalyx degradation, caused by depleted glutathione and inorganic sulfate levels, shear stress from circulating nanoparticles, aggregation and formation of protein coronas; leading to imbalanced immune responses and chronic release of pro-inflammatory cytokines, ultimately resulting in oxidative stress and systemic inflammatory response syndrome. By understanding the underlying pathophysiology of severe adverse events, better treatment options can be explored.

Acute aortoiliac thrombosis and mitral valve regurgitation as acute onset of eosinophilic granulomatosis with polyangiitis in a 26-year-old patient

We present a rare case of eosinophilic granulomatosis with polyangiitis (EGPA), involving a 26-year-old woman with a history of asthma and nasal polyps. The patient presented with acute aortoiliac thrombosis and mitral insufficiency, which was successfully treated with thrombolysis, aortic thromboendarterectomy, and valve replacement. Peripheral hypereosinophilia with eosinophilic infiltration of the heart led to the diagnosis of antineutrophilic cytoplasmic antibody-negative EGPA. Treatment with prednisone and mepolizumab was started, resulting in a positive outcome. This case showcases an unusual manifestation of EGPA with large size vessel involvement and requiring surgical and pharmacological treatment. It also highlights the importance of early detection for timely intervention and an improved prognosis.

Hematopoietic and eosinophil-specific LNK(SH2B3) deficiency promotes eosinophilia and arterial thrombosis

ABSTRACT

Increased eosinophil counts are associated with cardiovascular disease and may be an independent predictor of major cardiovascular events. However, the causality and underlying mechanisms are poorly understood. Genome-wide association studies have shown an association of a common LNK variant (R262W, T allele) with eosinophilia and atherothrombotic disorders. LNK(TT) reduces LNK function, and Lnk-deficient mice display accelerated atherosclerosis and thrombosis. This study was undertaken to assess the role of eosinophils in arterial thrombosis in mice with hematopoietic Lnk deficiency. Hematopoietic Lnk deficiency increased circulating and activated eosinophils, JAK/STAT signaling in eosinophils, and carotid arterial thrombosis with increased eosinophil abundance and extracellular trap formation (EETosis) in thrombi. Depletion of eosinophils by anti-Siglec-F antibody or by the ΔdbIGata1 mutation eliminated eosinophils in thrombi and markedly reduced thrombosis in mice with hematopoietic Lnk deficiency but not in control mice. Eosinophil depletion reduced neutrophil abundance and NETosis in thrombi without altering circulating neutrophil counts. To assess the role of Lnk specifically in eosinophils, we crossed Lnkf/f mice with eoCre mice. LnkΔeos mice displayed isolated eosinophilia, increased eosinophil activation, and accelerated arterial thrombosis associated with increased EETosis and NETosis in thrombi. DNase I infusion abolished EETs and neutrophil extracellular traps (NETs) in thrombi and reversed the accelerated thrombosis. Human induced pluripotent stem cell-derived LNK(TT) eosinophils showed increased activation and EETosis relative to isogenic LNK(CC) eosinophils, demonstrating human relevance. These studies show a direct link between eosinophilia, EETosis, and atherothrombosis in hematopoietic Lnk deficiency and an essential role of eosinophil LNK in suppression of arterial thrombosis.

Renal damage and old age: risk factors for thrombosis in patients with ANCA-associated vasculitis

INTRODUCTION

Thrombosis in ANCA-associated vasculitis (AAV) was prevalent and has been neglected in Chinese patients. This study tried to describe the clinical characteristics, identify the risk factors, and investigate the causal relationship between AAV and venous thromboembolism (VTE) by two-sample Mendelian randomization (MR) analysis.

METHODS

In this retrospective, observational study, we included all hospitalized AAV patients from Jan 2013 to Apr 2022 in Peking Union Medical College Hospital. We collected their clinical data for multivariate regression analysis to determine the risk factors for thrombosis. The nomogram was constructed by applying these risk factors to predict thrombosis in AAV patients. As for MR analysis, we selected single nucleotide polymorphisms (SNPs) related to AAV from published genome-wide association studies and extracted the outcome data containing deep vein thrombosis (DVT) and pulmonary embolism (PE) from the UK biobank.

RESULTS

1203 primary AAV patients were enrolled, and thrombosis occurred in 11.3%. Multivariate regression suggested that older than 65 years, EGPA, neurological involvement, lung involvement, significantly elevated serum creatinine (> 500µmol/L), and elevated D-dimer were associated with thrombosis in AAV patients. The model demonstrated satisfied discrimination with an AUC of 0.769 (95% CI, 0.726-0.812). MR analysis showed that EGPA could increase the risk of developing DVT and PE (OR = 1.0038, 95%CI = 1.0035-1.0041, P = 0.009).

CONCLUSION

Thrombosis was not rare in Chinese patients with AAV. Renal damage and old age emerged as critical risk factors for thrombosis. EGPA might have a potential causal relationship with DVT and PE.

PATHOPHYSIOLOGICAL MECHANISMS OF DEEP VEIN THROMBOSIS

Deep venous thrombosis is a frequent multifactorial disease and most of the time is triggered by the interaction between acquired risk factors, particularly immobility, and hereditary risk factors such as thrombophilias. The mechanisms underlying deep venous thrombosis are not fully elucidated; however, in recent years the role of venous flow, endothelium, platelets, leukocytes, and the interaction between inflammation and hemostasis has been determined. Alteration of venous blood flow produces endothelial activation, favoring the adhesion of platelets and leukocytes, which, through tissue factor expression and neutrophil extracellular traps formation, contribute to the activation of coagulation, trapping more cells, such as red blood cells, monocytes, eosinophils, lymphocytes. The coagulation factor XI-driven propagation phase of blood coagulation plays a major role in venous thrombus growth, but a minor role in hemostasis. In this work, the main mechanisms involved in the pathophysiology of deep vein thrombosis are described.

Complement Factor I Gene Variant in an Atypical Hemolytic Uremic Syndrome Triggered by Hypereosinophilia Syndrome

Atypical hemolytic uremic syndrome (aHUS) is a condition characterized by acute kidney injury (AKI), thrombocytopenia, and microangiopathic hemolytic anemia secondary to complement pathway dysregulation. Several triggers have been identified as causing aHUS in genetically susceptible patients; however, hypereosinophilia syndrome (HES)-triggered aHUS has not been reported. In this article, we present a case of aHUS presented with generalized urticarial rashes and angioedema. The initial investigations revealed hypereosinophilia (maximal absolute eosinophil count of 6,840 cells/µL) with normal bone-marrow analyses; hence, idiopathic HES was diagnosed. During hospitalization, the patient developed convulsion, stuporous, and full-blown thrombotic microangiopathy (TMA), with AKI requiring temporary hemodialysis. A kidney biopsy confirmed the existence of renal TMA. Next-generation sequencing of the coding regions of aHUS-related genes was performed, revealing an underlying complement factor I (CFI) deficiency, a heterozygous variant p.P64L of CFI gene. The patient was successfully treated with high-dose steroids and extended duration of plasmapheresis.

Fatal cerebral venous sinus thrombosis with preceding thrombocytopenia in a patient with new-onset eosinophilic granulomatosis with polyangiitis

A previously healthy, 44-year-old, female patient was hospitalised for acute abdominal pain and bilateral pneumonia. Eosinophilic granulomatosis with polyangiitis (EGPA) was diagnosed on the basis of eosinophilia, eosinophilic tissue inflammation, polyneuropathy, and bilateral pneumonia. She had a fatal cerebral venous sinus thrombosis following thrombocytopenia, which was apparently caused by platelet consumption. It may have been possible to prevent the deterioration of the venous thrombosis by starting immunosuppressive or anticoagulant therapy earlier. If a patient with EGPA presents with unexplained thrombocytopenia, the physician should assess for physical findings or laboratory abnormalities suggestive of thrombosis. Additionally, if the patient complains of headache or nausea with normal head computed tomography findings, magnetic resonance imaging or magnetic resonance venography should be performed to assess for cerebral venous sinus thrombosis.

Portal Vein Thrombosis as a Cause of Undetermined Thrombocytopenia with Liver Dysfunction in a Patient with Eosinophilic Granulomatosis with Polyangiitis

We herein report a 20-year-old woman who developed eosinophilic granulomatosis with polyangiitis (EGPA) and portal vein thrombosis (PVT). EGPA was diagnosed based on the patient's history of asthma, hypereosinophilia, and mononeuritis complex. Thrombocytopenia and liver dysfunction were observed, necessitating contrast-enhanced computed tomography (CECT), which revealed PVT. Her symptoms soon improved with glucocorticoids and anticoagulation therapy. As patients with EGPA often suffer from asthma, they can be hesitant to undergo CECT. However, if patients with EGPA show uncertain thrombocytopenia with liver dysfunction, a further evaluation using CECT is warranted to detect PVT.

At the Heart of Eosinophilic Granulomatosis with Polyangiitis: into Cardiac and Vascular Involvement

PURPOSE OF REVIEW

To provide an overview of existing literature on pathogenetic and clinical aspects of cardiac and vascular involvement in eosinophilic granulomatosis with polyangiitis (EGPA).

RECENT FINDINGS

In EGPA, cardiac and vascular involvement are more common than previously thought. However, no international recommendations on the topic are available yet. Herein, we summarize the existing evidence on the topic and propose a diagnostic approach for cardiac involvement in EGPA. The prevalence of cardiovascular involvement in patients with EGPA varies greatly among published studies, ranging between 3.1-18.7% for occlusive arterial disease, 5.8-30% for venous thrombosis and 17-92% for heart involvement. Cardiac involvement in EGPA is associated with high mortality even though manifestations are heterogeneous. In principle, every anatomical structure of the heart can be involved, and EGPA-related heart disease may be completely asymptomatic at first. A careful diagnostic work-up for early detection and prompt treatment initiation is therefore required. While cardiac manifestations are more common in anti-neutrophil cytoplasmic antibodies (ANCA)-negative patients, arterial and venous thrombotic events are not linked to ANCA status but correlate closely with disease activity and accumulate at disease onset. Thrombotic events (mainly venous) are considerably more frequent in EGPA than in the general population contributing substantially to morbidity and highlighting the importance of developing specific prevention strategies for patients who are diagnosed with EGPA.

Cardiac Magnetic Resonance in Rheumatology to Detect Cardiac Involvement Since Early and Pre-clinical Stages of the Autoimmune Diseases: A Narrative Review

Autoimmune diseases (ADs) encompass multisystem disorders, and cardiovascular involvement is a well-known feature of autoimmune and inflammatory rheumatic conditions. Unfortunately, subclinical and early cardiovascular involvement remains clinically silent and often undetected, despite its well-documented impact on patient management and prognostication with an even more significant effect on severe and future MACE events as the disease progresses. Cardiac magnetic resonance imaging (MRI), today, commands a unique position of supremacy versus its competition in cardiac assessment and is the gold standard for the non-invasive evaluation of cardiac function, structure, morphology, tissue characterization, and flow with the capability of evaluating biventricular function; myocardium for edema, ischemia, fibrosis, infarction; valves for thickening, large masses; pericardial inflammation, pericardial effusions, and tamponade; cardiac cavities for thrombosis; conduction related abnormalities and features of microvascular and large vessel involvement. As precise and early detection of cardiovascular involvement plays a critical role in improving the outcome of rheumatic and autoimmune conditions, our review aims to highlight the evolving role of CMR in systemic lupus erythematosus (SLE), antiphospholipid syndrome (APS), rheumatoid arthritis (RA), systemic sclerosis (SSc), limited sclerosis (LSc), adult-onset Still's disease (AOSD), polymyositis (PM), dermatomyositis (DM), eosinophilic granulomatosis with polyangiitis (EGPA) (formerly Churg-Strauss syndrome), and DRESS syndrome (DS). It draws attention to the need for concerted, systematic global interdisciplinary research to improve future outcomes in autoimmune-related rheumatic conditions with multiorgan, multisystem, and cardiovascular involvement.

Rituximab and dupilumab improve eosinophilic granulomatosis with polyangiitis with multiple pulmonary thrombi

Background

Eosinophilic granulomatosis with polyangiitis (EGPA) is characterized by a necrotizing vasculitis with tissue and peripheral blood eosinophilia affecting small and medium-sized arteries, capillaries, and veins. Venous thromboembolic events are uncommon in EGPA. Moreover, there are only a few reported cases of EGPA complicated by pulmonary embolism or infarction.

Case presentation

We report the case of a 43-year-old woman with eosinophilic granulomatosis with polyangiitis and acute respiratory and heart failure due to bilateral pulmonary artery thrombosis and left femoral vein thrombosis 12 years after disease onset. She also had cardiac involvement (myocarditis, pericardial effusion, and diastolic dysfunction), gastrointestinal symptoms, and peripheral neuropathy. The condition was refractory to treatment with systemic corticosteroids, intravenous cyclophosphamide, and mepolizumab, but the thrombosis and associated acute cardiac failure, as well as the cardiac and gastrointestinal symptoms and multiple polyneuropathy, improved after a switch to rituximab. However, the heart failure did not improve sufficiently and the patient continued to need inhaled oxygen at 1 L/min and asthma exacerbations occurred. We then swapped the patient’s mepolizumab treatment for dupilumab. Not only did she have no further asthma attacks after switching to dupilumab, but also her vasculitis symptoms improved. Oxygen therapy was discontinued as the heart failure improved 5 months after starting the dupilumab.

Conclusions

This may be the first case report of the successful treatment by rituximab of pulmonary thromboembolism associated with EGPA. In addition, in this patient, treatment with dupilumab was effective not only for the asthma symptoms but also for the symptoms of vasculitis and heart failure.

Increased Circulating Cell-Free DNA in Eosinophilic Granulomatosis With Polyangiitis: Implications for Eosinophil Extracellular Traps and Immunothrombosis

Background

Endogenous DNA derived from nuclei or mitochondria is released into the blood circulation as cell-free DNA (cfDNA) following cell damage or death. cfDNA is associated with various pathological conditions; however, its clinical significance in antineutrophil cytoplasmic antibody-associated vasculitis (AAV) remains unclear. This study aimed to evaluate the clinical significance of cfDNA in AAV.

Methods

We enrolled 35 patients with AAV, including 10 with eosinophilic granulomatosis with polyangiitis (EGPA), 13 with microscopic polyangiitis, and 12 with granulomatosis with polyangiitis. Serum cf-nuclear DNA (cf-nDNA) and cf-mitochondrial DNA (cf-mtDNA) levels were measured by quantitative polymerase chain reaction before and after the initiation of immunosuppressive therapy. Tissue samples from EGPA patients were examined by immunofluorescence and transmission electron microscopy. The structure of eosinophil extracellular traps (EETs) and neutrophil extracellular traps (NETs) and stability against DNase were assessed in vitro. Platelet adhesion of EETs were also assessed.

Results

Serum cf-nDNA and cf-mtDNA levels were significantly higher in AAV than in healthy controls, with the highest levels in EGPA; however, serum DNase activities were comparable among all groups. cf-nDNA and cf-mtDNA decreased after treatment and were associated with disease activity only in EGPA. Blood eosinophil count and plasma D-dimer levels were significantly correlated with cf-nDNA in EGPA and cf-mtDNA. EGPA tissue samples showed lytic eosinophils and EETs in small-vessel thrombi. The structure of EETs showed bolder net-like chromatin threads in vitro and EETs showed greater stability against DNase than NETs. EETs provided a scaffold for platelet adhesion.

Conclusion

cfDNA was increased in EGPA, associated with disease activity. The presence of DNase-resistant EETs in small-vessel thrombi might contribute to higher concentration of cfDNA and the occurrence of immunothrombosis in EGPA.

Rare case of recurrent stroke in a patient with eosinophilic granulomatosis with polyangiitis: a case report

Background

Central nervous system involvement is rarely described in eosinophilic granulomatosis with polyangiitis (EGPA) and occurs in 5–9% of patients. Among central nervous system manifestations, cerebral infarctions are the most common. To the best of our knowledge, a recurrent stroke in patients with EGPA without cardiac risk factors during maintenance therapy so far has not been described.

Case presentation

A previously healthy 57-year-old female during the course of 1 year developed asthma, sinusitis, polyneuropathy, muscle weakness, and rash followed by fatigue, myalgia, arthralgia, and fever. After an initial diagnostic evaluation, elevated values of eosinophils, liver enzymes, creatine kinase, lactate dehydrogenase, and inflammatory markers (sedimentation rate and C-reactive protein) were found, and renal impairment was detected. On the third day of hospitalization, she developed left-sided hemiparesis due to an ischemic stroke in the right basal ganglia. She has been diagnosed with EGPA, and oral corticosteroid, immunosuppressive, and antiplatelet therapy were applied. Despite potent treatment and initial recovery, a few weeks later, she developed recurrent ischemic stroke in the left hemisphere and pulmonary embolism as rare and potentially severe complications of EGPA. Assuming that complete disease remission had not been established previously, oral prednisone was initially substituted with intravenous methylprednisolone pulses. During follow-up, immunosuppressive therapy was slowly discontinued, oral corticosteroid therapy was reduced to a maintenance dose, and thromboembolic events were well controlled by oral anticoagulant therapy.

Conclusion

Anticoagulant therapy, in addition to immunosuppressive maintenance therapy, should be considered in any EGPA patient who has had an ischemic stroke even without cardiac risk factors.

Venous thrombosis and predictors of relapse in eosinophil-related diseases

Eosinophils have widespread procoagulant effects. Eosinophilic cardiovascular toxicity mostly consists of endomyocardial damage or eosinophilic vasculitis, while reported cases of venous thrombosis (VT) are scarce. We aimed to report on the clinical features and treatment outcomes of patients with unexplained VT and eosinophilia, and to identify predictors of relapse. This retrospective, multicenter, observational study included patients aged over 15 years with VT, concomitant blood eosinophilia ≥ 1G/L and without any other moderate-to-strong contributing factors for VT. Fifty-four patients were included. VT was the initial manifestation of eosinophil-related disease in 29 (54%) patients and included pulmonary embolism (52%), deep venous thrombosis (37%), hepatic (11%) and portal vein (9%) thromboses. The median [IQR] absolute eosinophil count at VT onset was 3.3G/L [1.6-7.4]. Underlying eosinophil-related diseases included FIP1L1-PDGFRA-associated chronic myeloid neoplasm (n = 4), Eosinophilic Granulomatosis with Polyangiitis (n = 9), lymphocytic (n = 1) and idiopathic (n = 29) variants of hypereosinophilic syndrome. After a median [IQR] follow-up of 24 [10-62] months, 7 (13%) patients had a recurrence of VT. In multivariate analysis, persistent eosinophilia was the sole variable associated with a shorter time to VT relapse (HR 7.48; CI95% [1.94-29.47]; p = 0.015). Long-term normalization of eosinophil count could prevent the recurrence of VT in a subset of patients with unexplained VT and eosinophilia ≥ 1G/L.

Eosinophilic granulomatosis with polyangiitis: understanding the disease and its management

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

Interplay between inflammation and thrombosis in cardiovascular pathology

Thrombosis is the most feared complication of cardiovascular diseases and a main cause of death worldwide, making it a major health-care challenge. Platelets and the coagulation cascade are effectively targeted by antithrombotic approaches, which carry an inherent risk of bleeding. Moreover, antithrombotics cannot completely prevent thrombotic events, implicating a therapeutic gap due to a third, not yet adequately addressed mechanism, namely inflammation. In this Review, we discuss how the synergy between inflammation and thrombosis drives thrombotic diseases. We focus on the huge potential of anti-inflammatory strategies to target cardiovascular pathologies. Findings in the past decade have uncovered a sophisticated connection between innate immunity, platelet activation and coagulation, termed immunothrombosis. Immunothrombosis is an important host defence mechanism to limit systemic spreading of pathogens through the bloodstream. However, the aberrant activation of immunothrombosis in cardiovascular diseases causes myocardial infarction, stroke and venous thromboembolism. The clinical relevance of aberrant immunothrombosis, referred to as thromboinflammation, is supported by the increased risk of cardiovascular events in patients with inflammatory diseases but also during infections, including in COVID-19. Clinical trials in the past 4 years have confirmed the anti-ischaemic effects of anti-inflammatory strategies, backing the concept of a prothrombotic function of inflammation. Targeting inflammation to prevent thrombosis leaves haemostasis mainly unaffected, circumventing the risk of bleeding associated with current approaches. Considering the growing number of anti-inflammatory therapies, it is crucial to appreciate their potential in covering therapeutic gaps in cardiovascular diseases.

The Maternal Leucocytes in Thrombophilia and Hypothyroidism and their Influence on Fetal Cells

The literature data show that thrombophilia and maternal dysfunction of thyroid gland during pregnancy are associated with an increased risk of miscarriage, placental abruption, hypertensive disorders and fetal growth retardation. It was shown that thyroid hormones and hypercoagulable states influence onto a leucocyte activity. The aim of this study has been to investigate maternal leucocytes changes and their correlation with frequency of fetal cells micronuclei in pregnant women with thrombophilia and hypothyroidism. The samples of blood and amniotic fluid were collected from healthy pregnant women and pregnant women with inherited thrombophilia and hypothyroidism (16 - 18 weeks of gestation). Hematological characteristics were determined by using standard hematological methods. The frequency of micronuclei was determined in fetal cells after amniocentesis by using standard cytogenetic methods. The results of this study showed significant higher levels of β-hCG, number of monocytes and eosinophils in blood of pregnant women with thrombophilia. A large number of eosinophils was documented in blood of pregnant women with hypothyroidism. Increased percentage distribution of eosinophils and basophils is shown in both investigated groups of pregnant women. The increased fetal cells micronuclei frequency and their correlation with percentage distribution of eosinophils and basophils were indicated in pregnant women with hypothyroidism. The obtained results suggest that an increased percentage of eosinophils and basophils in pregnant women with hypothyroidism contribute to a formation of micronuclei in fetal cells.

Eosinophil percentage as a new prognostic marker in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

Background

In addition to proinflammatory properties, eosinophils can stimulate platelet activation and enhance prothrombotic pathways. In this study, we aimed to investigate the association between the eosinophil percentage (EOS%) and major adverse cardiac events (MACE) in patients with ST-segment elevation myocardial infarction (STEMI).

Methods

This study enrolled a total of 1,909 patients who were diagnosed with STEMI. Ventricular arrhythmia, reinfarction, the need for cardiopulmonary resuscitation, target vessel revascularization, congestive heart failure, and cardiovascular mortality during index hospitalization were defined as MACE.

Results

Three hundred and eighty patients (19.7%) reached the combined endpoint with MACE. The rates of inhospital mortality and MACE were significantly higher in low EOS% group as compared to high EOS% group (4% vs. 1.1%, p < 0.01 and 32.8% vs. 11.3%, p < 0.01, respectively). On multivariate logistic regression analyses, EOS% (OR = 0.44, p < 0.01) was found to be one of the independent predictors of MACE. The EOS% lower than 0.60 on admission predicted inhospital MACE with a sensitivity of 68% and a specificity of 72% (AUC: 0.684, p < 0.01).

Conclusions

Low EOS% on admission may be associated with high inhospital MACE in STEMI patients. EOS% may be used as a novel biomarker for risk stratification of these patients.

Histopathological Study of a Broad Spectrum of Skin Dermatoses in Patients Affected or Highly Suspected of Infection by COVID-19 in the Northern Part of Italy: Analysis of the Many Faces of the Viral-Induced Skin Diseases in Previous and New Reported Cases

Skin manifestations of COVID-19 infections are diverse and are new to the dermatology community. We had the opportunity to examine the clinical and histopathological features of several patients who were divided into 3 groups. The first group included 8 COVID-19–positive patients who were hospitalized and quarantined at home. The second group included children and young adults who presented with chilblain erythema, erythema multiforme, and urticaria-like lesions. This group of patients was negative for the COVID-19 gene sequences by polymerase chain reaction but had a high risk of COVID-19 infection. The third group included clinically heterogeneous and challenging lesions. These patients were not subject to either polymerase chain reaction tests or serological analyses because they sought dermatological attention only for a dermatosis. The histopathological analysis of these cases showed a wide spectrum of histopathological patterns. What appears to be constant in all skin biopsies was the presence of prominent dilated blood vessels with a swollen endothelial layer, vessels engulfed with red blood cells, and perivascular infiltrates, consisting mainly of cytotoxic CD8+ lymphocytes and eosinophils. In 2 cases, there was diffuse coagulopathy in the cutaneous vascular plexus. In the early phases of the disease, there were numerous collections of Langerhans cells in the epidermis after being activated by the virus. The presence of urticarial lesions, chilblains, targetoid lesions (erythema multiforme–like lesions), exanthema, maculohemorrhagic rash, or chickenpox-like lesions associated with the histopathological features mentioned previously should cause clinical dermatologists to suspect the possibility of COVID-19 infection, especially in patients with fever and cough.

Retinal artery occlusion followed by contralateral amaurosis fugax in association with eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome)

Purpose

To describe two cases of retinal artery occlusion followed by contralateral amaurosis fugax associated with eosinophilic granulomatosis with polyangiitis (EGPA, formerly known as Churg-Strauss syndrome).

Observations

Case 1 is a 57 year-old male who presented with transient vision loss in the right eye two weeks after a cilioretinal artery occlusion in the left eye. Evaluation eventually led to a diagnosis of EGPA. The patient was treated with high-dose steroids followed by systemic immunomodulatory therapy. Vision in the right eye recovered to 20/20 with no further episodes of vision loss. Case 2 is a 55 year-old male with a known diagnosis of EGPA who presented with transient vision loss in the right eye four weeks after a central retinal artery occlusion of the left eye. This patient also successfully recovered vision in the right eye after treatment with high-dose steroids following a change in his systemic immunomodulatory therapy.

Conclusions and Importance

While ANCA-vasculitides are an uncommon cause of retinal artery occlusion and amaurosis fugax, it is important that they remain in the differential diagnosis, as good visual outcomes can be achieved with prompt initiation of appropriate therapies.

Combination of eosinophil percentage and high-sensitivity C-reactive protein predicts in-hospital major adverse cardiac events in ST-elevation myocardial infarction patients undergoing primary percutaneous coronary intervention

Background

Eosinophil levels predict prognosis in ST‐segment elevation myocardial infarction (STEMI) patients. Both eosinophils and high‐sensitivity C‐reactive protein (hs‐CRP) play a major role in the acute inflammatory response of myocardial infarction. The purpose of this study was to evaluate eosinophil percentage (EOS%) and hs‐CRP as prognostic markers for in‐hospital adverse events in STEMI patients undergoing primary percutaneous coronary intervention.

Methods

We retrospectively analyzed the clinical data of 518 patients. Major adverse cardiac events (MACEs) were defined as cardiac rupture, cardiac arrest, malignant arrhythmia, and cardiac death. Based on the receiver operating characteristic (ROC) analysis, all patients were regrouped into 3 groups (None, One, and Two) according to cutoff EOS% value (≤0.3%) and hs‐CRP value (>11.8 mg/L). Both Cox regression analyses and the KM (Kaplan‐Meier) survival curve were used to examine the prognostic role of combined hs‐CRP and EOS% in cardiovascular events.

Results

Of the 518 STEMI patients, 50 of them developed MACEs. Patients who developed MACEs had a significantly lower EOS% and higher hs‐CRP than patients who remained MACE‐free. In the multivariable Cox regression analysis, the highest risk of in‐hospital MACEs was constantly observed in patients with a combined low EOS% and elevated hs‐CRP. Patients with reduced EOS% and high hs‐CRP had significantly higher incidence rates of cardiac rupture (P = .001), cardiac arrest (P = .001), and malignant arrhythmia (P < .001); furthermore, they had the worst cumulative survival compared with the other two groups.

Conclusion

Combined reduced EOS% and elevated hs‐CRP were valuable tools for identifying patients at risk of in‐hospital MACEs.

Eosinophil-platelet interactions promote atherosclerosis and stabilize thrombosis with eosinophil extracellular traps

Clinical observations implicate a role of eosinophils in cardiovascular diseases because markers of eosinophil activation are elevated in atherosclerosis and thrombosis. However, their contribution to atherosclerotic plaque formation and arterial thrombosis remains unclear. In these settings, we investigated how eosinophils are recruited and activated through an interplay with platelets. Here, we provide evidence for a central importance of eosinophil-platelet interactions in atherosclerosis and thrombosis. We show that eosinophils support atherosclerotic plaque formation involving enhanced von Willebrand factor exposure on endothelial cells and augmented platelet adhesion. During arterial thrombosis, eosinophils are quickly recruited in an integrin-dependent manner and engage in interactions with platelets leading to eosinophil activation as we show by intravital calcium imaging. These direct interactions induce the formation of eosinophil extracellular traps (EETs), which are present in human thrombi and constitute a substantial part of extracellular traps in murine thrombi. EETs are decorated with the granule protein major basic protein, which causes platelet activation by eosinophils. Consequently, targeting of EETs diminished thrombus formation in vivo, which identifies this approach as a novel antithrombotic concept. Finally, in our clinical analysis of coronary artery thrombi, we identified female patients with stent thrombosis as the population that might derive the greatest benefit from an eosinophil-inhibiting strategy. In summary, eosinophils contribute to atherosclerotic plaque formation and thrombosis through an interplay with platelets, resulting in mutual activation. Therefore, eosinophils are a promising new target in the prevention and therapy of atherosclerosis and thrombosis.

Do blood eosinophils strictly reflect airway inflammation in COPD? Comparison with asthmatic patients

Introduction

Airway eosinophilic inflammation is a characteristic of asthmatic patients and of a sub group of COPD subjects. Blood eosinophils are deemed as a good surrogate marker of sputum eosinophilic inflammation; however, controversial data have been published particularly in COPD. The aim of our study was to compare blood and sputum eosinophils in COPD and asthmatic patients in “real life”.

Methods

Sputum was induced in stable patients with COPD or asthma with hypertonic saline solution and blood eosinophils were evaluated. Frequency of comorbidities was recorded. Correlations were performed stratifying patients by disease and comorbidities.

Results

146 patients, 57 with COPD and 89 with asthma were evaluated. Blood and sputum eosinophils expressed as percentages were correlated in COPD (rho = 0.40; p = 0.004), but the entity of correlation was lower compared with asthmatic subjects (rho = 0.71; p < 0.0001). When blood eosinophils were expressed as counts the correlation was slightly lower than when expressed as percentages in COPD (rho = 0.35; p = 0.01) and in asthmatic patients (rho = 0.68; p < 0.0001). In COPD patients older than 73 years or with blood eosinophils higher than the median value (210.6 eos/μl), or co-diagnosed with hypertension, ischemic heart disease or atrial fibrillation no correlation between blood and sputum eosinophils was found.

However, the effect of ischemic heart disease and atrial fibrillation could be driven by hypertension since most of these patients have this comorbidity.

Conclusion

Blood eosinophils correlated with sputum eosinophils to a lesser degree in COPD than in asthmatic patients. Older age, high blood eosinophils and hypertension affected the correlation between blood and sputum eosinophils, more studies are needed to evaluate the role of other cardiac comobidities.

A delayed diagnosis of eosinophilic granulomatosis with polyangiitis complicated with extensive artery occlusion of lower extremities in children: case report and literature review

BACKGROUND

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare systemic vasculitis in children. A delayed or missed diagnosis of pediatric EGPA is common, owing to the atypical clinical manifestation and limited recognition of this disorder. The vasculitis in EGPA typically involves small to medium size vessels. Extensive occlusion of arteries in the extremities was being extremely rare and has never been reported in children.

CASE PRESENTATION

A 10-year and 10-month-old girl with recurrent wheezing and breathlessness during exercise, was initially diagnosed with asthma at the age of five years. Despite unexplained manifestations, including intermittent remarkably increased eosinophilia, uncontrolled allergic rhinitis, and recurrent petechia, from the onset of asthma through to its remission, the consideration of EGPA was completely ignored until the patient presented with aggravated petechia and severe ulceration of the lower extremities, associated with extensive stenosis and/or occlusion of the arteries of the shank and foot. Given her history of asthma, eosinophilia, allergic rhinitis, mononeuropathy, pulmonary infiltrates, and vasculitis confirmed by the skin biopsy, the diagnosis of EGPA was ultimately confirmed. Regrettably, the initial inappropriate and irrational use of corticosteroid failed to relieve the symptoms until more aggressive treatment with intravenous methylprednisolone was started. This was followed by methotrexate treatment, with tapering of prednisone, without relapse over a six-month follow-up.

CONCLUSIONS

Pediatric rheumatologists should be alert to the possibility of EGPA in children with refractory asthma associated with unexplained manifestations, and should be aware of the thromboembolic complications as vascular sequelae of EGPA.

Behçet's syndrome as a tool to dissect the mechanisms of thrombo-inflammation: clinical and pathogenetic aspects

Behçet's syndrome (BS) is a complex disease with different organ involvement. The vascular one is the most intriguing, considering the existence of a specific group of patients suffering from recurrent vascular events involving the venous and, more rarely, the arterial vessels. Several clinical clues suggest the inflammatory nature of thrombosis in BS, especially of the venous involvement, thus BS is considered a model of inflammation-induced thrombosis. Unique among other inflammatory conditions, venous involvement (together with the arterial one) is currently treated with immunosuppressants, rather than with anti-coagulants. Although many in-vitro studies have suggested the different roles of the multiple players involved in clot formation, in-vivo models are crucial to study this process in a physiological context. At present, no clear mechanisms describing the pathophysiology of thrombo-inflammation in BS exist. Recently, we focused our attention on BS patients as a human in-vivo model of inflammation-induced thrombosis to investigate a new mechanism of clot formation. Indeed, fibrinogen displays a critical role not only in inflammatory processes, but also in clot formation, both in the fibrin network and in platelet aggregation. Reactive oxygen species (ROS)-derived modifications represent the main post-translational fibrinogen alterations responsible for structural and functional changes. Recent data have revealed that neutrophils (pivotal in the pathogenetic mechanisms leading to BS damage) promote fibrinogen oxidation and thrombus formation in BS. Altogether, these new findings may help understand the pathogenetic bases of inflammation-induced thrombosis and, more importantly, may suggest potential targets for innovative therapeutic approaches.

Thrombotic microangiopathy in a patient with eosinophilic granulomatosis with polyangiitis: case-based review

The correct diagnosis, classification and therapeutic management of thrombotic microangiopathies (TMA) continue to be a challenge for the clinician. We report a rare case of eosinophilic granulomatosis with polyangiitis (EGPA) as a trigger for complement-mediated TMA in a 57-year-old man who was successfully treated with corticoids, cyclophosphamide and therapeutic plasma exchange. Additionally, we review few other cases reported in the literature and the pathophysiological pathway of association between TMA and EGPA. We found that the mutual relationships between the inflammation triggered by vasculitis, the exacerbated complement activation, together with hypereosinophilia and endothelial damage seem to be the key in explaining the connection between both entities. We suggest that an understanding of the multi-causal nature of TMAs is crucial for the correct diagnosis and treatment of these patients.

Portal Vein Thrombosis and Thrombocytopenia in Eosinophilic Granulomatosis with Polyangiitis: A Paradox?

A 36-year-old woman with eosinophilic granulomatosis with polyangiitis (EGPA) presented with necrotic skin lesions and pulmonary infiltrates. There was eosinophilic vasculitis on skin biopsy, and substantial tissue eosinophilia in her bone marrow. She had unexplained worsening thrombocytopenia, which prompted a thrombophilia work-up. However, abnormalities in liver enzymes led to the extraordinary finding of portal vein thrombosis. Thrombocytopenia resolved with treatment with low molecular weight heparin. This case highlights the risk of hypercoagulability in eosinophilia specifically, and in EGPA. We suggest that thrombosis should be ruled out in all cases of EGPA.

Pulmonary embolism and deep vein thrombosis in eosinophilic granulomatosis with polyangiitis successfully treated with rivaroxaban

A 41-year-old woman presented complaining of cough and purpura for one month. On her first visit, a blood test demonstrated peripheral blood eosinophilia, but chest radiography showed no abnormalities. However, 2 days after the first visit, she went to the emergency room because of fever and right-sided chest pain. Contrast-enhanced computed tomography of the chest showed pulmonary embolism and air space consolidation. Thrombosis was present in the popliteal vein. Bronchoscopy revealed alveolar hemorrhage and increased eosinophils in the bronchoalveolar lavage fluid, and a skin biopsy demonstrated a perivascular eosinophilic infiltrate. The patient was diagnosed with eosinophilic granulomatosis with polyangiitis (EGPA). We started steroid therapy and low-molecular-weight heparin (LMWH). The chest pain and fever disappeared, and the peripheral eosinophil count normalized. However, the thrombosis in the leg worsened. It was dramatically improved by changing from LMWH to oral rivaroxaban. The thrombogenic risk of eosinophilia should be recognized. This case suggests that oral rivaroxaban is useful when thrombosis is uncontrolled by LMWH in a patient with EGPA.

Enzymatic lipid oxidation by eosinophils propagates coagulation, hemostasis, and thrombotic disease

Blood coagulation is essential for physiological hemostasis but simultaneously contributes to thrombotic disease. However, molecular and cellular events controlling initiation and propagation of coagulation are still incompletely understood. In this study, we demonstrate an unexpected role of eosinophils during plasmatic coagulation, hemostasis, and thrombosis. Using a large-scale epidemiological approach, we identified eosinophil cationic protein as an independent and predictive risk factor for thrombotic events in humans. Concurrent experiments showed that eosinophils contributed to intravascular thrombosis by exhibiting a strong endogenous thrombin-generation capacity that relied on the enzymatic generation and active provision of a procoagulant phospholipid surface enriched in 12/15-lipoxygenase-derived hydroxyeicosatetraenoic acid-phosphatidylethanolamines. Our findings reveal a previously unrecognized role of eosinophils and enzymatic lipid oxidation as regulatory elements that facilitate both hemostasis and thrombosis in response to vascular injury, thus identifying promising new targets for the treatment of thrombotic disease.

Limb-Threatening Arterial Thrombosis in a Patient with Eosinophilic Granulomatosis with Polyangiitis

Eosinophilic granulomatosis (EGPA), or Churg-Strauss syndrome, is a rare and necrotizing systemic vasculitis, which affects small-to-medium-sized vessels and often manifests with severe asthma and eosinophilia. We report a case of a 72 year-old male with a two-year lung-biopsy proven history of EGPA who presented with retiform purpura and patchy necrosis on his bilateral shins, which progressed to sharply demarcated, stellate ulcerations with surrounding erythema within two weeks. Laboratory work up revealed elevated anti-Cardiolipin IgM, rheumatoid factor, erythrocyte sedimentation rate, and C-reactive protein, although P-neutrophil cytoplasmic antibody (P-ANCA) and C-neutrophil cytoplasmic antibody (C-ANCA) were negative. Vascular studies revealed long anterior tibial and dorsalis pedis artery occlusion and severe small vessel disease in plantar digital arteries. Despite treatment with intravenous cyclophosphamide, pulse-dose methylprednisolone, and pentoxifylline, the patient experienced disease progression and limb threatening arterial thrombosis. This case highlights the importance of vascular and neuropathic sequelae that may result from untreated or undertreated EGPA in P-ANCA-negative patients without active pulmonary symptoms.

Aggressive eosinophilic granulomatosis with polyangiitis and transverse sinus thrombosis

We report a case of a patient with eosinophilic granulomatosis with polyangiitis (EGPA, previously known as Churg-Strauss syndrome) who succumbed to respiratory failure complicated by sepsis, pneumonitis and transverse sinus thrombosis. In the absence of antineutrophilic cytoplasmic antibodies positivity, a clinical diagnosis was made based on The American College of Rheumatology-1990 criteria. Glucocorticoids, cyclophosphamide, rituximab and intravenous immunoglobulin were administered at different stages. The patient recovered momentarily after each cycle of treatment, but his vasculitis progressed and he eventually died. Cardiac or renal involvement, which is more commonly associated with an adverse outcome, was not present.

Unfavorably Altered Fibrin Clot Properties in Patients with Eosinophilic Granulomatosis with Polyangiitis (Churg-Strauss Syndrome): Association with Thrombin Generation and Eosinophilia

Objectives

Given reports on the increased prevalence of thromboembolic incidents in patients with eosinophilic granulomatosis with polyangiitis (EGPA; Churg-Strauss syndrome), we investigated whether fibrin clot properties are unfavorably altered in EGPA.

Methods

Ex vivo plasma fibrin clot characteristics, including clot permeability, turbidimetry and efficiency of fibrinolysis using two assays, were investigated in 34 consecutive patients with remission in EGPA according to the Birmingham Vasculitis Activity Score version 3 (23 female, 11 male), aged 48 (range, 21–80) years. The control group comprised 34 age- and sex- matched volunteers.

Results

Compared with controls, patients with EGPA were characterized by denser fiber clots (estimated pore size, K_s, 7.30±0.93 vs 10.14±1.07 10⁻⁹ cm²), faster fibrin polymerization (lag phase in a turbidimetric curve, 41.8±3.6 vs 47.4±2.9 s), thicker fibrin fibers (maximum absorbance, ΔAbs, 0.87±0.09 vs 0.72±0.07), higher maximum levels of D-dimer released from clots (DD_max 4.10±0.46 vs 3.54±0.35 mg/L), and prolonged clot lysis time (t_50%; 9.50±1.45 vs 7.56±0.87 min); all p<0.0001. Scanning electron microscopy images confirmed denser plasma fibrin networks composed of thinner fibers formed in EGPA. Antineutrophil cytoplasmic antibody status and C-reactive protein did not affect clot variables. Multivariate analysis adjusted for fibrinogen showed that K_s was predicted by eosinophil count, peak thrombin generation, factor VIII, and soluble CD40 ligand, whereas eosinophil count, peak thrombin generation and antiplasmin predicted t_50%.

Conclusion

This study is the first to show that EGPA is associated with prothrombotic plasma fibrin clot phenotype, which may contribute to thromboembolic manifestations reported in this disease.

Thrombosis in vasculitis: from pathogenesis to treatment

In recent years, the relationship between inflammation and thrombosis has been deeply investigated and it is now clear that immune and coagulation systems are functionally interconnected.

Inflammation-induced thrombosis is by now considered a feature not only of autoimmune rheumatic diseases, but also of systemic vasculitides such as Behçet’s syndrome, ANCA-associated vasculitis or giant cells arteritis, especially during active disease.

These findings have important consequences in terms of management and treatment. Indeed, Behçet’syndrome requires immunosuppressive agents for vascular involvement rather than anticoagulation or antiplatelet therapy, and it is conceivable that also in ANCA-associated vasculitis or large vessel-vasculitis an aggressive anti-inflammatory treatment during active disease could reduce the risk of thrombotic events in early stages.

In this review we discuss thrombosis in vasculitides, especially in Behçet’s syndrome, ANCA-associated vasculitis and large-vessel vasculitis, and provide pathogenetic and clinical clues for the different specialists involved in the care of these patients.

Venous thromboembolism in systemic autoimmune diseases: A narrative review with emphasis on primary systemic vasculitides

Venous thromboembolism (VTE) is a prevalent multifactorial health condition associated with significant morbidity and mortality. Population-based epidemiological studies have revealed an association between systemic autoimmune diseases and deep venous thrombosis (DVT)/VTE. The etiopathogenesis of increased risk of VTE in systemic autoimmune diseases is not entirely clear but multiple contributors have been explored, especially in the context of systemic inflammation and disordered thrombogenesis. Epidemiologic data on increased risk of VTE in patients with primary systemic vasculitides (PSV) have accumulated in recent years and some of these studies suggest the increased risk while patients have active diseases. This could lead us to hypothesize that venous vascular inflammation has a role to play in this phenomenon, but this is unproven. The role of immunosuppressive agents in modulating the risk of VTE in patients with PSV is not yet clear except for Behçet’s disease, where most of the studies are retrospective. Sensitizing physicians to this complication has implications for prevention and optimal management of patients with these complex diseases. This review will focus on the epidemiology and available evidence regarding pathogenesis, and will attempt to summarize the best available data regarding evaluation and treatment of these patients.

Enhanced tissue factor expression by blood eosinophils from patients with hypereosinophilia: a possible link with thrombosis

Thrombotic risk is increased in eosinophil-mediated disorders, and several hypotheses have been proposed to link eosinophilia and thrombosis. In particular, eosinophils have been described as source of tissue factor (TF), the main initiator of blood coagulation; however, this aspect is still controversial. This study was aimed to evaluate whether TF expression varies in eosinophils isolated from normal subjects and patients with different hypereosinophilic conditions. Eosinophils were immunologically purified from peripheral blood samples of 9 patients with different hypereosinophilic conditions and 9 normal subjects. Western blot analysis and real-time polymerase chain reaction (RT-PCR) were performed to test eosinophil TF expression. For comparison, TF expression was evaluated in monocytes from blood donors and in human endothelial (ECV304) and fibroblast (IMR90) cell lines. Western blot analysis revealed a major band of 47,000 corresponding to native TF in homogenates of purified eosinophils with a higher intensity in the 9 patients than in the 9 controls (p<0.0001). According to RT-PCR cycle threshold (Ct), TF gene expression was higher in eosinophils from patients than in those from controls, median (range) 35.10 (19.45-36.50) vs 37.17 (35.33-37.87) (p = 0.002), and was particularly abundant in one patient with idiopathic hypereosinophilic syndrome and ischemic heart attacks (Ct: 19.45). TF gene expression was moderate in monocytes, Ct: 31.32 (29.82-33.49) and abundant in endothelial cells, Ct: 28.70 (27.79-29.57) and fibroblasts, Ct: 22.77 (19.22-25.05). Our results indicate that human blood eosinophils contain variable amounts of TF. The higher TF expression in patients with hypereosinophilic disorders may contribute to increase the thrombotic risk.

Eosinophils in vasculitis: characteristics and roles in pathogenesis

Eosinophils are multifunctional granular leukocytes that are implicated in the pathogenesis of a wide variety of disorders, including asthma, helminth infection, and rare hypereosinophilic syndromes. Although peripheral and tissue eosinophilia can be a feature of many types of small-vessel and medium-vessel vasculitis, the role of eosinophils has been best studied in eosinophilic granulomatosis with polyangiitis (EGPA), where eosinophils are a characteristic finding in all three clinical stages of the disorder. Whereas numerous studies have demonstrated an association between the presence of eosinophils and markers of eosinophil activation in the blood and tissues of patients with EGPA, the precise role of eosinophils in disease pathogenesis has been difficult to ascertain owing to the complexity of the disease process. In this regard, results of clinical trials using novel agents that specifically target eosinophils are providing the first direct evidence of a central role of eosinophils in EGPA. This Review focuses on the aspects of eosinophil biology most relevant to the pathogenesis of vasculitis and provides an update of current knowledge regarding the role of eosinophils in EGPA and other vasculitides.