Risk of acute arterial and venous thromboembolic events in eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome)

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.

Benralizumab for eosinophilic granulomatosis with polyangiitis: a retrospective, multicentre, cohort study

BACKGROUND

Interleukin-5 (IL-5) inhibitors represent novel therapies for eosinophilic granulomatosis with polyangiitis (EGPA). This study assessed the effectiveness and safety of the IL-5 receptor inhibitor benralizumab in a European cohort of patients with EGPA.

METHODS

This retrospective cohort study included patients with EGPA from 28 European referral centres of the European EGPA Study Group across six countries (Italy, France, UK, Russia, Spain, and Switzerland) who received benralizumab as any line of treatment between Jan 1, 2019, and Sep 30, 2022. We assessed the rates of complete response, defined as no disease activity (Birmingham Vasculitis Activity Score [BVAS] of 0) and a prednisone dose of up to 4 mg/day, in contrast to partial response, defined as a BVAS of 0 and a prednisone dose greater than 4 mg/day. Active disease manifestations, pulmonary function, variation in glucocorticoid dose, and safety outcomes were also assessed over a 12-month follow-up.

FINDINGS

121 patients with relapsing-refractory EGPA treated with benralizumab at the dose approved for eosinophilic asthma were included (64 [53%] women and 57 [47%] men; median age at the time of beginning benralizumab treatment 54·1 years [IQR 44·2-62·2]). Complete response was reported in 15 (12·4%, 95% CI 7·1-19·6) of 121 patients at month 3, 25 (28·7%, 19·5-39·4) of 87 patients at month 6, and 32 (46·4%, 34·3-58·8) of 69 patients at month 12; partial response was observed in an additional 43 (35·5%, 27·0-44·8) patients at month 3, 23 (26·4%, 17·6-37·0) at month 6, and 13 (18·8%, 10·4-30·1) at month 12. BVAS dropped from 3·0 (IQR 2·0-8·0) at baseline to 0·0 (0·0-2·0) at months 3 and 6, and to 0·0 (0·0-1·0) at month 12. The proportion of patients with systemic manifestations, active peripheral neurological disease, ear, nose, and throat involvement, and pulmonary involvement decreased, with an improvement in lung function tests. Six patients relapsed after having a complete response. The oral prednisone (or equivalent) dose decreased from 10·0 mg/day (5·0-12·5) at baseline to 5·0 mg/day (3·6-8·5) at month 3 (p<0·01), to 5·0 mg/day (2·5-6·3) at month 6, and to 2·5 mg/day (0·0-5·0) at month 12 (p<0·0001). 19 (16%) of 121 patients had adverse events and 16 (13%) discontinued benralizumab.

INTERPRETATION

These data suggest that benralizumab could be an effective treatment for EGPA in real-life clinical practice. Further clinical trials are required to confirm the efficacy of benralizumab in patients with a higher baseline disease activity.

FUNDING

None.

Eosinophilic Granulomatosis with Polyangiitis: Latest Findings and Updated Treatment Recommendations

Eosinophilic granulomatosis with polyangiitis (EGPA) causes necrotizing vasculitis and eosinophil-rich granulomatous inflammation in small- to medium-sized vessels, resulting in multiple organ damage. EGPA is classified as an antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, with myeloperoxidase-ANCA detected in approximately one-third of the patients. Conventional treatment of EGPA relies on systemic glucocorticoids (GCs) in combination with cyclophosphamide when poor prognostic factors are present; however, the dilemma between disease control and drug-related adverse effects has long been a challenge. Recent studies have revealed that the genetic background, pathophysiology, and clinical manifestations differ between ANCA-positive and ANCA-negative patients; however, mepolizumab, an interleukin (IL)-5 inhibitor, is effective in both groups, suggesting that the IL-5-eosinophil axis is deeply involved in the pathogenesis of both ANCA-positive and ANCA-negative EGPA. This review summarizes the latest knowledge on the pathophysiology of EGPA and focuses on the roles of eosinophils and ANCA. We then introduce the current treatment recommendations and accumulated evidence for mepolizumab on EGPA. Based on current unmet clinical needs, we discuss potential future therapeutic strategies for EGPA.

Evidence-Based Guideline for the diagnosis and management of eosinophilic granulomatosis with polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, characterized by asthma, eosinophilia and granulomatous or vasculitic involvement of several organs. The diagnosis and management of EGPA are often challenging and require an integrated, multidisciplinary approach. Current practice relies on recommendations and guidelines addressing the management of ANCA-associated vasculitis and not specifically developed for EGPA. Here, we present evidence-based, cross-discipline guidelines for the diagnosis and management of EGPA that reflect the substantial advances that have been made in the past few years in understanding the pathogenesis, clinical subphenotypes and differential diagnosis of the disease, as well as the availability of new treatment options. Developed by a panel of European experts on the basis of literature reviews and, where appropriate, expert opinion, the 16 statements and five overarching principles cover the diagnosis and staging, treatment, outcome and follow-up of EGPA. These recommendations are primarily intended to be used by healthcare professionals, pharmaceutical industries and drug regulatory authorities, to guide clinical practice and decision-making in EGPA. These guidelines are not intended to limit access to medications by healthcare agencies, nor to impose a fixed order on medication use.

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

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

Risk of acute myocardial infarction, stroke, and venous thromboembolism among patients with anti-neutrophil cytoplasmic antibody-associated vasculitis in South Korea: A nationwide population-based study

OBJECTIVES

To investigate the incidence and risk of cerebro-cardiovascular comorbidities (stroke, acute myocardial infarction, venous thromboembolism, and pulmonary embolism) in anti-neutrophil cytoplasmic antibody-associated vasculitis using nationwide Korean population-based medical claims data.

METHODS

We identified 1905 patients with newly diagnosed anti-neutrophil cytoplasmic antibody-associated vasculitis during 2009-2019. Incidence rates and hazard ratios with 95% confidence intervals were calculated to estimate the risk of cerebro-cardiovascular comorbidities in these patients and compared to age- and sex-matched controls (1:10) using the Cox proportional hazards model.

RESULTS

Most patients had microscopic polyangiitis (42.5%), followed by granulomatosis with polyangiitis (29.1%) and eosinophilic granulomatosis with polyangiitis (28.4%). The annual incidence rate of anti-neutrophil cytoplasmic antibody-associated vasculitis in 2019 was 0.55 per 100,000 person-years. Cerebro-cardiovascular comorbidities occurred in 12.6%. Stroke was most common (64.6%), followed by venous thromboembolism (34.6%), pulmonary embolism (18.3%), and acute myocardial infarction (5.4%). Korean patients with anti-neutrophil cytoplasmic antibody-associated vasculitis were at a significantly (2.3 times) higher overall risk for cerebro-cardiovascular comorbidities than the general population (adjusted hazard ratios, 4.5, 3.1, and 2.0 times higher for pulmonary embolism, venous thromboembolism, and stroke, respectively). These findings were similar for patients with each subtype of anti-neutrophil cytoplasmic antibody-associated vasculitis.

CONCLUSIONS

This is the first nationwide population-based study to demonstrate a significant risk of cerebro-cardiovascular comorbidities as complications of anti-neutrophil cytoplasmic antibody-associated vasculitis in Korean patients. Knowing these risks may enable personalized patient care and improve overall survival.

Evidence of subclinical atherosclerosis in eosinophilic granulomatosis with polyangiitis

OBJECTIVES

Patients affected by eosinophilic granulomatosis with polyangiitis (EGPA) display an increased risk of atherothrombotic events compared with the general population. An increased frequency of subclinical markers of atherosclerosis has been observed in other ANCA-associated vasculitis, but no specific study focused on EGPA. We therefore evaluated subclinical atherosclerosis in EGPA patients and in a control population.

METHODS

Forty EGPA patients and 80 controls matched by age, sex and traditional cardiovascular risk factors underwent sonographic assessment of common carotid artery (CCA) intima-media thickness (IMT). The presence of plaques of the CCA was also investigated. The correlation between CCA-IMT and clinical and laboratory features was also assessed.

RESULTS

Median CCA-IMT was significantly higher in EGPA patients compared with controls (P = 0.002). Also, the proportion of subjects with increased CCA-IMT and with presence of plaques was significantly higher among EGPA patients (P < 0.001 for both). Moreover, within the EGPA cohort, CCA-IMT tended to increase with disease duration (P = 0.034) and corticosteroid cumulative dose (P = 0.004). No significant associations were found between CCA-IMT, ANCA status, other clinical features and therapeutic regimens. Notably, the prevalence of traditional cardiovascular risk factors was comparable in patients with vs without an increased CCA-IMT.

CONCLUSION

Ultrasound markers of subclinical atherosclerosis are increased in EGPA patients as compared with controls, independently of traditional cardiovascular risk factors.

A Review of Anti-IL-5 Therapies for Eosinophilic Granulomatosis with Polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA), previously known as Churg-Strauss syndrome, is a systemic disorder characterized by asthma, eosinophilia, and vasculitis primarily affecting small vessels. Although this disease is classified as an anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis along with microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA), observations suggest that eosinophils play a vital role in the pathophysiology of EGPA. Therefore, biopsy specimens derived from patients with EGPA demonstrated an increase in eosinophils within the vascular lumen and extravascular interstitium, especially in patients negative for ANCA. In addition, active secretion of eosinophil intracellular components by cytolysis and piecemeal degranulation occurs in the extravascular interstitium and bloodstream. Although the treatment for EGPA is described in the context of ANCA-associated vasculitis along with MPA and GPA, a therapeutic approach to suppress eosinophils is also considered. Monoclonal antibodies directed against interleukin-5 (IL-5) or its receptors are good therapeutic agents because IL-5 plays an important role in eosinophil growth, activation, and survival. Currently, mepolizumab (Nucala), reslizumab (Cinqair), and benralizumab (Fasenra) have been studied for use in patients with EGPA. These monoclonal antibodies were initially approved for use in patients with severe eosinophilic asthma. Mepolizumab is now approved for treating EGPA following the success of phase 3 randomized controlled trial. Therefore, further studies are needed to clarify long-term safety and efficacy of anti-IL-5 agents and establish indications of individual therapeutic agents tailored to individual conditions of patients with EGPA.

Peripheral Eosinophil Count Is Associated With the Prognosis of Patients With Type B Aortic Dissection Undergoing Endovascular Aortic Repair: A Retrospective Cohort Study

Background Eosinophil count (EOS) has been proposed to provide prognostic information in multiple cardiovascular disorders. However, few researchers have investigated the predictive value of EOS for patients with type B aortic dissection who had thoracic endovascular repair. Methods and Results The authors reviewed the records of 912 patients with type B aortic dissection who were treated with thoracic endovascular repair in Changhai Hospital, Shanghai. By using receiver operating characteristic curve analysis, patients were divided into 2 groups based on the admission EOS cutoff value (<7.4×10⁶/L [n=505] and ≥7.4×10⁶/L [n=407]). To reduce selection bias, propensity score matching was applied. Multivariable regression analysis and Kaplan-Meier curves were performed to assess the association between EOS and long-term outcomes. Furthermore, we investigated nonlinear correlations between EOS and outcomes using general additive models with restricted cubic splines. In the matched population, lower EOS was associated with significantly higher 30-day mortality (4.1% vs 0%, P=0.007). There was no statistically difference in 30-day adverse events between the 2 groups (all P>0.05). Kaplan-Meier analysis revealed that patients with an EOS <7.4×10⁶/L had a higher incidence of 1-year all-cause death (7.95% vs. 2.34%, P=0.008) and aortic-related death (5.98% vs 1.81%, P=0.023) than those with higher EOS. Multivariable Cox analysis showed that continuous EOS was independently associated with 1-year mortality (hazard ratio, 3.23 [95% CI, 1.20-8.33], P=0.019). In addition, we discovered a nonlinear association between EOS and 1-year outcomes. Conclusions Lower admission EOS values predict higher short- and long-term mortality after thoracic endovascular repair.

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.

Arterial and venous thromboembolism risk associated with blood eosinophils: A systematic review and meta-analysis

The association between blood eosinophil (EOS) counts and arterial/venous thrombosis is unclear. We aim to explore whether EOS count is a risk factor for thrombosis. We searched several databases and preprint platforms using core terms ‘eosinophil’, ‘myocardial infarction’, ‘ischemic stroke’, and ‘venous thromboembolism’ (VTE), among others. Studies comparing the odds ratios (ORs) or risk ratios (RRs) of EOSs with the abovementioned diseases were eligible. Overall, 22 studies were included. A high EOS count was associated with acute coronary artery thrombosis events (OR: 1.23, 95% CI: 1.15–1.32), short‐term cerebral infarction and mortality (RR: 2.87, 95% CI: 1.49–5.51). The short‐term risk of VTE was more common in patients with EOS‐related diseases (RR: 6.52, 95% CI: 2.42–17.54). For coronary artery disease, a high EOS count was a protective factor against 6‐month to 1‐year mortality (RR: 0.56, 95% CI: 0.45–0.69) but was associated with long‐term mortality (RR: 1.64, 95% CI: 1.25–2.14). Therefore, we conclude that for coronary artery thrombosis, EOS count is not associated with AMI events in general population. It may be associated with NSTEMI and STEMI in CAD patients, but more studies are needed to confirm this. In addition, EOS count is associated with an increased risk of both short‐ and long‐term mortality but is not predictive of the composite endpoints. For cerebral artery thrombosis, EOS count may be associated with cerebral infarction and could lead to an increased risk of poor short‐term prognosis. For VTEs, EOS count was a risk factor for some patients, especially those with acute‐phase EOS‐related diseases.

Genetics of ANCA-associated vasculitis: role in pathogenesis, classification and management

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) comprises granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (EGPA), that share features of pauci-immune small-vessel vasculitis and the positivity of ANCA targeting proteinase-3 (PR3-ANCA) or myeloperoxidase (MPO-ANCA). AAV syndromes are rare, complex diseases and their aetio-pathogenesis is mainly driven by the interaction between environmental and genetic factors. In patients with GPA and MPA, the genetic associations are stronger with ANCA specificity (PR3- versus MPO-ANCA) than with the clinical diagnosis, which, in keeping with the known clinical and prognostic differences between PR3-ANCA-positive and MPO-ANCA-positive patients, supports an ANCA-based re-classification of these disorders. EGPA is also made up of genetically distinct subsets, which can be stratified on ANCA-status (MPO ANCA-positive versus ANCA-negative); these subsets differ in clinical phenotype and possibly in their response to treatment. Interestingly, MPO-ANCA-positive patients with either MPA or EGPA have overlapping genetic determinants, thus strengthening the concept that this EGPA subset is closely related to the other AAV syndromes. The genetics of AAV provides us with essential information to understand its varied phenotype. This Review discusses the main findings of genetic association studies in AAV, their pathogenic implications and their potential effect on classification, management and prognosis.

In vivo visualization of eosinophil secretion in eosinophilic granulomatosis with polyangiitis: An ultrastructural study

BACKGROUND

Although eosinophilic granulomatosis with polyangiitis (EGPA) has been considered as a single disease entity belonging to anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, several studies have suggested that in addition to the mechanisms associated with ANCA, those associated with eosinophils play a vital role in tissue damage. Nevertheless, the morphological bases underlying eosinophil-associated lesions have not been completely elucidated.

METHODS

We investigated the electron microscopic findings of sural nerve biopsy specimens obtained from 18 patients with EGPA by focusing on the behavior of eosinophils, particularly the mode of secretion.

RESULTS

Eosinophils tended to be located at sites close to endothelial cells within the lumina of epineurial small vessels. Attachment of eosinophils to endothelial cells was observed, particularly at the junction between neighboring endothelial cells, and some of these eosinophils appeared to escape from the vascular lumen to migrate into the extravascular interstitium. Furthermore, we observed eosinophil degranulation via piecemeal degranulation and cytolysis. Degranulating eosinophils were identified in both intravascular and extravascular compartments. Some of the small vessels appeared to be occluded by numerous eosinophils, and eosinophils attached by platelets were also observed, suggesting that coagulopathy occurs in EGPA.

CONCLUSIONS

Both extravascular and intravascular eosinophils can induce tissue damage unrelated to classical necrotizing vasculitis associated with ANCA in patients with EGPA. Further research is necessary to elucidate the molecular basis of the induction of these fine structural changes, which will contribute to the development of targeted therapies based on specific mechanisms of eosinophil-related diseases.

Eosinophilic granulomatosis with polyangiitis: an unusual cause of stroke

Stroke has become increasingly common with the rise in hyperlipidaemia, hypertension and other metabolic disorders. In this case, a 69-year-old man with several weeks of non-specific symptoms and no history of metabolic disorders presents with unilateral weakness and supraventricular tachycardia. Kidney biopsy confirmed a diagnosis of eosinophilic granulomatosis with polyangiitis. He responded well to rituximab infusions.

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.

ANCA-Associated Vasculitic Neuropathies: A Review

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis is a systemic disorder that frequently affects the peripheral nervous system and consists of three distinct conditions: microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA, previously Wegener’s granulomatosis), and eosinophilic granulomatosis with polyangiitis (EGPA, previously Churg-Strauss syndrome). The neuropathic features associated with this condition usually include mononeuritis multiplex, which reflects the locality of lesions. Findings suggestive of vasculitis are usually found in the epineurium and occur diffusely throughout the nerve trunk. Nerve fiber degeneration resulting from ischemia is sometimes focal or asymmetric and tends to become conspicuous at the middle portion of the nerve trunk. The attachment of neutrophils to endothelial cells in the epineurial vessels is frequently observed in patients with ANCA-associated vasculitis; neutrophils play an important role in vascular inflammation by binding of ANCA. The positivity rate of ANCA in EGPA is lower than that in MPA and GPA, and intravascular and tissue eosinophils appear to participate in neuropathy. Immunotherapy for ANCA-associated vasculitis involves the induction and maintenance of remission to prevent the relapse of the disease. A combination of glucocorticoids along with cyclophosphamide, rituximab, methotrexate, or mycophenolate mofetil is considered depending on the severity of the condition of the organ to induce remission. A combination of low-dose glucocorticoids and azathioprine, rituximab, methotrexate, or mycophenolate mofetil is recommended to maintain remission. The efficacy of anti-interleukin-5 therapy (i.e., mepolizumab) was demonstrated in the case of refractory or relapsing EGPA. Several other new agents, including avacopan, vilobelimab, and abatacept, are under development for the treatment of ANCA-associated vasculitis. Multidisciplinary approaches are required for the diagnosis and management of the disorder because of its systemic nature. Furthermore, active participation of neurologists is required because the associated neuropathic symptoms can significantly disrupt the day-to-day functioning and quality of life of patients with ANCA-associated vasculitis.

Mepolizumab for Eosinophilic Granulomatosis with Polyangiitis (EGPA): a European multicenter observational study

OBJECTIVE

Mepolizumab proved efficacious for eosinophilic granulomatosis with polyangiitis (EGPA, former Churg-Strauss) at the dosage of 300mg/4 weeks in the randomized controlled MIRRA trial. Few successful real-life experiences with the dosage approved for severe eosinophilic asthma (100mg/4 weeks) were recently reported. We retrospectively assessed the effectiveness and safety of mepolizumab 100 and 300mg/4 weeks in a large European EGPA cohort.

METHODS

We included all EGPA patients treated with mepolizumab at the recruiting centres in 2015-2020. Treatment response was evaluated from month 3 through 24 (T3-T24) after mepolizumab starting. Complete response (CR) was defined as no disease activity (Birmingham Vasculitis Activity Score, BVAS=0) and a prednisone dose ≤4mg/day. Respiratory outcomes included asthma and ear-nose-throat (ENT) exacerbations.

RESULTS

We included 203 patients, of whom 191 at stable dosage (158 mepolizumab 100mg/4 weeks, 33 300mg/4 weeks). At T3, 25 patients (12.3%) had a CR. CR rates increased to 30.4% and 35.7% at T12 and T24 and were comparable between mepolizumab 100 and 300mg/4 weeks. Mepolizumab led to a significant reduction in BVAS, prednisone dose, eosinophil counts from T3 through T24, with no significant differences between 100 and 300 mg/4weeks. Eighty-two patients (40.4%) experienced asthma exacerbations [57/158 (36%) on 100mg/4 weeks; 17/33 (52%) on 300mg/4 weeks]. Thirty-one (15.3%) experienced ENT exacerbations. Forty-four patients (21.7%) experienced adverse events, most being non-serious (38/44).

CONCLUSION

Mepolizumab both at 100 and 300mg/4 weeks is effective for EGPA. The two dosages should be compared in the setting of a controlled trial.

Eosinophilic Granulomatosis With Polyangiitis: Dissecting the Pathophysiology

Eosinophilic Granulomatosis with Polyangiitis (EGPA) is a rare multisystemic disease classified both amongst hypereosinophilic disorders and ANCA-associated vasculitis. Vessel inflammation and eosinophilic proliferation are the hallmarks of the disease and main effectors of organ damage. Two distinct disease phenotypes have classically been described according to ANCA-status: the ANCA-negative subset with eosinophil-driven manifestation and the ANCA-positive one with vasculitic manifestations. An analogous dichotomization has also been backed by histological findings and a distinct genetic background. EGPA is typically consider a Th2-mediated disease and blood and tissue eosinophilia represent the cornerstone of diagnosis. Besides, ANCA are known for inducing endothelial injury and vascular inflammation by activating the circulating neutrophils. Thus, the pathogenesis of EGPA seems to be mediated by two coexisting mechanisms. However, the verbatim application of this strict dualism cannot always be translated into routine clinical practice. In the present review we describe the current knowledge on the eosinophilic and ANCA-mediated aspects of EGPA pathogenesis. Finally, we review the rationale of the currently proposed EGPA dichotomy and future research perspectives.