[Modern Perspectives on Peripheral Neuropathology].

Recent advances in genetic and antibody testing have limited pathological examination of peripheral nerve specimens. However, when examining peripheral neuropathological findings from a modern perspective, there is often an opportunity to comprehend previously unnoticed observations upon re-examining the same specimen. For example, electron microscopy studies have suggested that the components that distinguish between nodal regions and internodes play a pivotal role in the behavior of macrophages that initiate myelin phagocytosis in the demyelinating form of Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy (CIDP). Conversely, some patients previously diagnosed with CIDP were found to possess distinctive mechanisms initiated by autoantibodies against paranodal junction proteins such as neurofascin 155 leading to the emergence of the concept of autoimmune nodopathy. In vasculitis, the roles of neutrophils in antineutrophil cytoplasmic antibody-associated vasculitis, eosinophils in eosinophilic granulomatosis with polyangiitis, and complements in nonsystemic vasculitic neuropathy in tissue damage have also been demonstrated when viewed from a modern perspective. Furthermore, mechanisms attributable to predominant small-fiber loss in hereditary transthyretin amyloidosis have been clarified at an ultrastructural level.

The role of anti-eosinophilic therapies in eosinophilic granulomatosis with polyangiitis: a systematic review.

Eosinophilic granulomatosis with polyangiitis (EGPA) is an antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, mostly affecting small-sized arteries and usually occurring in patients with an allergic background. Eosinophils seem to play a significant role in the pathogenesis of the disease and, therefore, biologics targeting interleukin 5 (IL5), a cytokine tightly linked to eosinophils, have emerged as a promising therapeutic tool. A systematic review of Medline was conducted from 2007 to 2022 to search for data regarding the use of anti-IL5 therapies in patients with EGPA. Ongoing or unpublished trials were also searched in ClinicalTrials.gov and the World Health Organization trials portal. The efficacy and safety of mepolizumab, an anti-IL5 monoclonal antibody (mAb), was confirmed by a randomized controlled trial (RCT), although a significant proportion of patients did not respond to this treatment. Other studies showed that both doses of 100 mg and 300 mg of mepolizumab are almost equally effective in EGPA. Benralizumab, an anti-IL5 receptor mAb has preliminary promising results and an RCT is planned to be conducted. Apart from their clinical efficacy in EGPA, anti-IL5 therapies may have steroid-sparing properties. Anti-IL5 therapies seem to be effective and safe in patients with refractory/relapsing EGPA and can be used as a steroid-sparing treatment. Nevertheless, more research is needed to clarify the pathophysiology of the disease; this may potentially lead to the identification of biomarkers to pinpoint patients most likely to respond to anti-IL5-blockade.

Systemic eosinophilic disease presenting as dacryoadenitis.

Eosinophilic disease with orbital involvement is rare. We present two patients with dacryoadenitis associated with local and systemic eosinophilia. A 32-year-old man presented with episodic dacryoadenitis, lower respiratory inflammation and peripheral eosinophilia. Lung and lacrimal gland biopsies demonstrated eosinophilic infiltrate without granuloma, necrosis, or vasculitis. He improved with oral corticosteroids and Mepolizumab, an IL-5 inhibitor. The second case involved a 33-year-old man who similarly presented with episodic dacryoadenitis, pulmonary inflammation and pain/swelling in the hands and feet. Lacrimal gland biopsy demonstrated a predominantly eosinophilic infiltrate without granuloma or vasculitis. Symptoms improved with oral corticosteroids. Although neither patient was provided a definitive diagnosis, both were determined to have an eosinophilic condition on the spectrum of eosinophilic asthma or eosinophilic granulomatosis with polyangiitis.

Clinical characteristics of eosinophilic granulomatosis with polyangiitis involving the lung in 13 patients. / 13ä¾‹ç´¯åŠè‚ºéƒ¨çš„å—œé ¸æ€§è‚‰èŠ½è‚¿æ€§å¤šè¡€ç®¡ç‚Žçš„ä¸´åºŠç‰¹å¾.

OBJECTIVES: Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare systemic vasculitis, which often starts with respiratory symptoms such as asthma, and it is difficult to make early clinical diagnosis.This study aims to improve the therapeutic level of EGPA with lung involvement via analyzing the clinical characteristics, diagnosis, and treatment . METHODS: We retrospectively analyzed the clinical data of 13 EGPA patients with lung involvement who were diagnosed from February 1, 2014 to July 31, 2021 in the Second Xiangya Hospital, Central South University. RESULTS: The ratio of male to female in 13 patients was 7꞉6. The patients were diagnosed at median age 52 (46-68) years old and 6 had been diagnosed as "bronchial asthma". Pulmonary clinical manifestations mainly included cough, expectoration, wheezing, and shortness of breath; while extra-pulmonary manifestations mainly included rash and subcutaneous mass, fever, limb numbness, muscle and joint pain, abdominal pain, etc. Peripheral blood tests of all patients showed that 11 patients had eosinophils ≥10%, 10 had elevated inflammatory indicators, and 3 were anti-neutrophil cytoplasmic antibody (ANCA) positive. The major lung imaging features were patches or strips of increased density, multiple nodules, bronchiectasis, bronchial wall thickening, exudation, mediastinal lymph nodes, and so on. Eight patients had sinusitis and 9 with abnormal electromyography. Extravascular eosinophil infiltration was found in 9 patients. Six patients with lung biopsy showed eosinophil, lymphocyte, and plasma cell infiltration, 3 patients were involved in small blood vessels, and 1 had granuloma. Pulmonary function tests were performed in 7 patients, 5 of them showed different degrees of pulmonary ventilation dysfunction, and 4 of them had diffusion dysfunction. Almost all patients respond well to glucocorticoid and immunosuppressant. CONCLUSIONS: EGPA is rare in clinical, often involving multiple systems with great harm and may combine with asthmatic manifestations. Pulmonary involvement is relatively common. However, due to insufficient recognition of this disease and huge heterogeneity of pulmonary imaging manifestations, misdiagnosis and missed diagnosis are easy to occur. Relevant laboratory, imaging, and biopsy examination should be performed as early as possible with comprehensive consideration of extrapulmonary involvement. Early identification has great significance to improve the diagnosis rate and prognosis of diseases.

Updates in ANCA-associated vasculitis.

Antineutrophil cytoplasm antibody (ANCA)-associated vasculitides (AAV) are small-vessel vasculitides that include granulomatosis with polyangiitis (formerly Wegener's granulomatosis), microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis (Churg - Strauss syndrome). Renal-limited AAV can be considered a fourth entity. Despite their rarity and still unknown cause(s), research into AAV has been very active over the past decades and has allowed for the development of new therapeutic regimens. The pathogenesis is a complex process of immune dysregulations with genetic and environmental influences. Recent genome-wide association studies have identified multiple genetic predisposing variants, especially at the major histocompatibility complex region. The pathogenic role of antimyeloperoxidase ANCA (MPO-ANCA) is well supported by several animal models, but that of antiproteinase 3 ANCA (PR3-ANCA) is not as strongly demonstrated. B cells likely play a major role in the pathogenesis because they produce ANCAs, as do neutrophil abnormalities, imbalances in T-cell subtypes, and/or cytokine - chemokine networks. The role of the alternative complement pathway was established more recently, and studies of the antagonist of human C5a receptor (avacopan) in AAV have just been completed, with promising results. The current standard management of severe AAV still consists of remission induction therapy with glucocorticoids combined with rituximab or, less often now, cyclophosphamide. Several studies showed that reduced-dose regimens of glucocorticoids are noninferior to the previously used heavier regimens, for therefore less cumulative exposure to glucocorticoids. Avacopan use may even lead to new steroid-free therapeutic approaches, at least for some selected patients. Several trials and studies have now shown the superiority of rituximab over azathioprine or methotrexate as maintenance therapy. However, the optimal dosing regimen and duration for maintenance remain to be better defined, at the individual patient level. Many changes have occurred in the standard of care for AAV over the past decades, and more are expected soon, including with use of avacopan, but also, likely, a few other agents under investigation or development.

[A Case of Transverse Colon Cancer Complicated by Eosinophilic Granulomatosis with Polyangiitis].

A man in his 50s had undergone steroid therapy for eosinophilic granulomatosis with polyangiitis(EGPA). Since an examination for malignant tumors revealed type 0-Ⅰsp(cT1aN0M0)and type 2(cT2N0M0)lesions in the proximal and mid- transverse colon, respectively, he was referred to our department. Endoscopic resection was performed on the proximal lesion. After the confirmation of curative resection, laparoscopic partial colectomy(transverse colon)and D3 lymph node dissection were performed on the mid-transverse lesion. Because of the patient's favorable postoperative course, he was discharged from the hospital on POD17. Since steroids and immunosuppressants may cause immunological abnormalities and malignant tumors, such patients should be strictly followed up.

Eosinophilic granulomatosis with polyangiitis: Cutaneous clinical and histopathologic differential diagnosis.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare, but severe systemic vasculitis that can affect skin and other organ systems. Diagnostic criteria have evolved, and many attempts have been made to classify the vasculitides based on clinical and/or histopathologic features, with an aim to develop standardized criteria. According to the EGPA Consensus Task Force recommendations, EGPA is a syndrome of asthma, eosinophilia, pulmonary infiltrates, and extrapulmonary vasculitis (such as cutaneous involvement with purpura). Histopathologic evidence of vasculitis in EGPA may be associated with eosinophilic infiltration and/or perivascular granulomatous inflammation. We review clinicopathologic criteria of this enigmatic vasculopathy.

A role for IL-33-activated ILC2s in eosinophilic vasculitis.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare but serious disease with poorly understood mechanisms. Here, we report that patients with EGPA have elevated levels of TSLP, IL-25, and soluble ST2, which are well-characterized cytokine "alarmins" that activate or modulate type 2 innate lymphoid cells (ILC2s). Patients with active EGPA have a concurrent reduction in circulating ILC2s, suggesting a role for ILC2s in the pathogenesis of this disease. To explore the mechanism of these findings in patients, we established a model of EGPA in which active vasculitis and pulmonary hemorrhage were induced by IL-33 administration in predisposed, hypereosinophilic mice. In this model, induction of pulmonary hemorrhage and vasculitis was dependent on ILC2s and signaling through IL4Rα. In the absence of IL4Rα or STAT6, IL-33-treated mice had less vascular leak and pulmonary edema, less endothelial activation, and reduced eotaxin production, cumulatively leading to a reduction of pathologic eosinophil migration into the lung parenchyma. These results offer a mouse model for use in future mechanistic studies of EGPA, and they suggest that IL-33, ILC2s, and IL4Rα signaling may be potential targets for further study and therapeutic targeting in patients with EGPA.

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.

Neutrophil infiltrates and eosinophil aggregates in chronic rhinosinusitis with nasal polyps and EGPA.

INTRODUCTION/OBJECTIVES: The histopathological study of inflammatory cells and their tendency to form aggregates in chronic rhinosinusitis with nasal polyps (CRSwNP) has shown promising results in determining the pathogenesis and predicting clinical outcome. Bilateral nasal polyps also occur in over 70% of patients with eosinophilic granulomatosis with polyangiitis (EGPA). The study aim was to investigate neutrophil infiltrates and eosinophil aggregates in CRSwNP and EGPA tissues of Caucasian patients. METHOD: A histopathological study was performed on surgical specimens of nasal polyps from 144 adults (15 with allergic fungal rhinosinusitis; 19 with nonsteroidal anti-inflammatory drugs-exacerbated respiratory disease (NERD); 16 with intrinsic asthma; 21 with extrinsic asthma; 21 with allergy; 22 with eosinophil CRSwNP (ECRSwNP); 17 with non-ECRSwNP; 13 with EGPA). RESULTS: Focusing on the presence of tissue eosinophil aggregates, NERD and ECRSwNP were the sub-cohorts with the highest rate. Neutrophil infiltrate rate was significantly higher in EGPA sub-cohort than in all CRSwNP sub-cohorts apart from non-ECRSwNP. CONCLUSIONS: Structured histopathology is increasingly identifying the different histotypes of CRSwNP. This analysis can be used to better understand CRSwNP endotypes and develop targeted therapies. The response to therapy and therefore control of CRSwNP relapses definitely depends on our ability to act on the underlying inflammatory pattern. Key points • Systematic analysis of how neutrophil infiltrates and eosinophilic aggregates are distributed in the different phenotypes of CRSwNP and EGPA. • Neutrophil infiltrates and eosinophil aggregates are strong risk factors for nasal polyps' refractoriness. • NERD and ECRSwNP are the sub-cohorts of CRSwNP with the highest rate of tissue eosinophil aggregates. • Neutrophil infiltrates are significantly higher in EGPA.

Relapse rate and renal prognosis in ANCA-associated vasculitis according to long-term ANCA patterns.

Long-term observation of patients with ANCA-associated vasculitis (AAV) allows the identification of different longitudinal patterns of ANCA levels during follow-up. This study aimed to characterize these patterns and to determine their prognostic significance. All ANCA determinations performed in two university hospitals during a 2-year period were retrospectively reviewed. Patients were included in the analysis if they had high titers of anti-myeloperoxidase (anti-MPO) or anti-proteinase 3 (anti-PR3) antibodies at least once, ≥ 5 serial ANCA determinations and AAV diagnosed by biopsy or American College of Rheumatology (ACR) classification criteria. Patients' time-course ANCA patterns were classified as monophasic, remitting, recurrent or persistent. Associations between ANCA patterns and prognostic variables (relapse rate and renal outcome) were analysed by univariate and multivariate statistics. A total of 99 patients [55 with microscopic polyangiitis (MPA), 36 with granulomatosis with polyangiitis (GPA) and eight with eosinophilic granulomatosis with polyangiitis (EGPA)] were included. Median follow-up was 9 years. Among patients diagnosed with MPA or GPA, recurrent or persistent ANCA patterns were associated with a higher risk of clinical relapse [hazard ratio (HR) = 3·7, 95% confidence interval (CI) = 1·5-9·1 and HR = 2·9, 95% CI = 1·1-8·0, respectively], independently of clinical diagnosis or ANCA specificity. In patients with anti-MPO antibodies, the recurrent ANCA pattern was associated with worsening renal function [odds ratio (OR) = 5·7, 95% CI = 1·2-26·0]. Recurrent or persistent ANCA patterns are associated with a higher risk of clinical relapse. A recurrent ANCA pattern was associated with worsening renal function in anti-MPO-associated vasculitis.

Renal involvement in eosinophilic granulomatosis with polyangiitis (EGPA): a multicentric retrospective study of 63 biopsy-proven cases.

OBJECTIVE: Eosinophilic granulomatosis with polyangiitis (EGPA) is a systemic small-vessel vasculitis characterized by asthma, hypereosinophilia and ANCA positivity in 40% of patients. Renal involvement is rare and poorly described, leading to this renal biopsy-proven based study in a large EGPA cohort. METHODS: We conducted a retrospective multicentre study including patients fulfilling the 1990 ACR criteria and/or the 2012 revised Chapel Hill Consensus Conference criteria for EGPA and/or the modified criteria of the MIRRA trial, with biopsy-proven nephropathy. RESULTS: Sixty-three patients [27 women, median age 60 years (18-83)] were included. Renal disease was present at vasculitis diagnosis in 54 patients (86%). ANCA were positive in 53 cases (84%) with anti-MPO specificity in 44 (83%). All patients had late-onset asthma. Peripheral neuropathy was present in 29 cases (46%), alveolar haemorrhage in 10 (16%). The most common renal presentation was acute renal failure (75%). Renal biopsy revealed pauci-immune necrotizing GN in 49 cases (78%). Membranous nephropathy (10%) and membranoproliferative GN (3%) were mostly observed in ANCA-negative patients. Pure acute interstitial nephritis was found in six cases (10%); important interstitial inflammation was observed in 28 (44%). All patients received steroids with adjunctive immunosuppression in 54 cases (86%). After a median follow-up of 51 months (1-296), 58 patients (92%) were alive, nine (14%) were on chronic dialysis and two (3%) had undergone kidney transplantation. CONCLUSION: Necrotizing pauci-immune GN is the most common renal presentation in ANCA-positive EGPA. ANCA-negative patients had frequent atypical renal presentation with other glomerulopathies such as membranous nephropathy. An important eosinophilic interstitial infiltration was observed in almost 50% of cases.

Myocardial involvement in eosinophilic granulomatosis with polyangiitis evaluated with cardiopulmonary magnetic resonance.

Patients with eosinophilic granulomatosis with polyangiitis (EGPA) most commonly die from cardiac causes, however, cardiac involvement remains poorly characterised and the relationship between cardiac and pulmonary disease is not known. This study aimed to characterise myocardial and pulmonary manifestations of EGPA, and their relationship. Prospective comprehensive cardiopulmonary investigation, including a novel combined cardiopulmonary magnetic resonance imaging (MRI) technology, was performed in 13 patients with stable EGPA. Comparison was made with 11 prospectively recruited matched healthy volunteers. Stable EGPA was associated with focal replacement and diffuse interstitial myocardial fibrosis (myocardial extracellular volume 26.9% vs. 24.7%; p = 0.034), which drove a borderline increase in left ventricular mass (56  ±  9 g/m2 vs. 49  ±  8 g/m2; p = 0.065). Corrected QT interval was significantly prolonged and was associated with the severity of myocardial fibrosis (r = 0.582, p = 0.037). Stable EGPA was not associated with increased myocardial capillary permeability or myocardial oedema. Pulmonary tissue perfusion and capillary permeability were normal and there was no evidence of pulmonary tissue oedema or fibrosis. Forced expiratory volume in one second showed a strong inverse relationship with myocardial fibrosis (r = -0.783, p = 0.038). In this exploratory study, stable EGPA was associated with focal replacement and diffuse interstitial myocardial fibrosis, but no evidence of myocardial or pulmonary inflammation or pulmonary fibrosis. Myocardial fibrosis was strongly associated with airway obstruction and abnormal cardiac repolarisation. Further investigation is required to determine the mechanisms underlying the association between heart and lung disease in EGPA and whether an immediate immunosuppressive strategy could prevent myocardial fibrosis formation.

Immunopathogenesis of ANCA-Associated Vasculitis.

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis is an autoimmune disorder which affects small- and, to a lesser degree, medium-sized vessels. ANCA-associated vasculitis encompasses three disease phenotypes: granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). This classification is largely based on clinical presentations and has several limitations. Recent research provided evidence that genetic background, risk of relapse, prognosis, and co-morbidities are more closely related to the ANCA serotype, proteinase 3 (PR3)-ANCA and myeloperoxidase (MPO)-ANCA, compared to the disease phenotypes GPA or MPA. This finding has been extended to the investigation of biomarkers predicting disease activity, which again more closely relate to the ANCA serotype. Discoveries related to the immunopathogenesis translated into clinical practice as targeted therapies are on the rise. This review will summarize the current understanding of the immunopathogenesis of ANCA-associated vasculitis and the interplay between ANCA serotype and proposed disease biomarkers and illustrate how the extending knowledge of the immunopathogenesis will likely translate into development of a personalized medicine approach in the management of ANCA-associated vasculitis.

Updates for the treatment of EGPA.

Eosinophilic granulomatosis with polyangiitis (EGPA, formerly Churg-Strauss syndrome) is the least frequent antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV). Major advances of our knowledge on its pathophysiology have revealed features of both AAV and eosinophilic disorders. The development of targeted biotherapies for both diseases opened new possibilities for EGPA management. In this review, we highlight the rationale underlying the routine treatment strategy, which relies mainly on corticosteroids, with immunosuppressant adjunction for severe disease. However, novel therapies are still needed for refractory/relapsing disease and to alleviate the corticosteroid-dependence of asthma and chronic rhinosinusitis. At present, the most promising biotherapies target either eosinophil biology, like mepolizumab, an anti-interleukin-5, or the B-cell compartment, with rituximab. Recent clinical data on new treatment options are discussed and therapeutic strategies are proposed.

Lung involvement in ANCA-associated vasculitis.

Lung involvement is one of the most common clinical features in ANCA-associated vasculitides (AAV), including granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). In this review, we detail the five main presentations of pulmonary involvement in AAV: necrotizing granulomatous inflammation, tracheobronchial inflammation, pulmonary capillaritis, interstitial lung disease (ILD) and asthma with their clinical, radiological and therapeutic characteristics. The prevalence of these manifestations is variable according to the subtype of AAV, necrotizing granulomatous inflammation and tracheobronchial inflammation being defining features of GPA whereas ILD is primarily seen in patients with MPA, especially in association with ANCA directed against myeloperoxydase (MPO-ANCA), and asthma is characteristic of EGPA. Despite recent progresses in the diagnosis and management of these conditions, several questions remain and are discussed here, including local treatments for subglottic stenosis, the uncertain efficacy of plasma exchanges for alveolar hemorrhage, the potential role of antifibrotic agents in ILD associated with MPA, and the use of novel anti-IL-5 strategies in EGPA.