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Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis consists of two main diseases, granulomatosis with polyangiitis and microscopic polyangiitis, and remains among the most devastating and potentially lethal forms of autoimmune inflammatory disease. Granulomatosis with polyangiitis and microscopic polyangiitis are characterised by a necrotising vasculitis that can involve almost any organ, and have generally been studied together. The diseases commonly affect the kidneys, lungs, upper respiratory tract, skin, eyes, and peripheral nerves. Granulomatous inflammation and multinucleated giant cells are key pathological hallmarks of granulomatosis with polyangiitis, but are absent in microscopic polyangiitis. Many immune system events are essential to disease aetiopathogenesis, such as activation of the alternative complement pathway, neutrophil activation via complement receptors, and the influx of inflammatory cells, including monocytes and macrophages. These cells perpetuate inflammation and lead to organ damage. During the 21st century, the management of ANCA-associated vasculitis has moved away from reliance on cytotoxic medications and towards targeted biological medications for both the induction and maintenance of disease remission. Earlier diagnosis, partly the result of more reliable ANCA testing, has led to improved patient outcomes and better survival. Reductions in acute disease-related mortality have now shifted focus to long-term morbidities related to ANCA-associated vasculitis and their treatments, such as chronic kidney disease and cardiovascular disease. Therapeutic approaches in both clinical trials and clinical practice still remain too reliant on glucocorticoids, and continued efforts to reduce toxicity from glucocorticoids remain a priority in the development of new treatment strategies. [ABSTRACT FROM AUTHOR]

Objective To investigate the occurrence of venous thromboembolic events (VTE) in a large cohort of patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) across the European Union, Turkey, Russia, UK and North America. Methods Patients with a definite diagnosis of AAV who were followed for at least 3 months and had sufficient documentation were included. Data on VTE, including either deep vein thrombosis or pulmonary embolism, were collected retrospectively from tertiary vasculitis centres. Univariate and multivariate regression models were used to estimate odds ratios (ORs) and 95% CIs. Results Over a median follow-up of 63 (interquartile range: 29, 101) months, VTE occurred in 278 (9.7%) of 2869 AAV patients with a similar frequency across different countries (from 6.3% to 13.7%), and AAV subtype [granulomatosis with polyangiitis: 9.8% (95% CI: 8.3, 11.6%); microscopic polyangiitis: 9.6% (95% CI: 7.9, 11.4%); and eosinophilic granulomatosis with polyangiitis: 9.8% (95% CI: 7.0, 13.3%)]. Most VTE (65.6%) were reported in the first-year post-diagnosis. Multiple factor logistic regression analysis adjusted for sex and age showed that skin (OR 1.71, 95% CI: 1.01, 2.92), pulmonary (OR 1.78, 95% CI: 1.04, 3.14) and kidney [eGFR 15–60 ml/min/1.73 m2, OR 2.86 (95% CI: 1.27, 6.47); eGFR <15 ml/min/1.73 m2, OR 6.71 (95% CI: 2.94, 15.33)] involvement were independent variables associated with a higher occurrence of VTE. Conclusion Two-thirds of VTE occurred during the initial phase of active disease. We confirmed previous findings from smaller studies that a decrease in kidney function, skin involvement and pulmonary disease are independently associated with VTE. [ABSTRACT FROM AUTHOR]

Plasma exchange (PLEX) is capable of removing significant amounts of circulating antibodies. In anti-neutrophil cytoplasmic antibody-associated vasculitis, PLEX was reserved for patients with severe presentation forms such as rapidly progressive glomerulonephritis and pulmonary haemorrhage. The Plasma Exchange and Glucocorticoids in Severe ANCA-Associated Vasculitis (PEXIVAS) trial included all comers with a glomerular filtration rate <50 mL/min/1.73 m2 and thus aimed to answer the question of whether PLEX is an option for patients with no relevant kidney function impairment or not. PEXIVAS revealed that after a follow-up of almost 3 years, routine administration of PLEX does not provide an additional benefit to reduce the rate of a composite comprising end-stage kidney disease or death. In the absence of histological parameters, it is tempting to speculate whether PLEX is effective or not in those with a potential for renal recovery. A subset of patients presented with alveolar haemorrhage, and there was a trend towards a better outcome of such cases receiving PLEX. This would be in line with observational studies reporting a recovery of alveolar haemorrhage following extracorporeal treatment. In this PRO part of the debate, we highlight the shortcomings of the PEXIVAS trial and stimulate further research paths, which in our eyes are necessary before abandoning PLEX from the therapeutic armamentarium. [ABSTRACT FROM AUTHOR]

Since the first description of infections with severe acute respiratory syndrome coronavirus 2 (SARSCoV- 2) in China in December 2019, it has evolved into a pandemic and emerged as an unprecedented worldwide crisis overwhelming healthcare systems globally. Analysis of the available literature to date suggests that, in addition to older age, patients with underlying co-morbidities including hypertension, diabetes, heart disease are at higher risk for severe disease with increased mortality. Practitioners around the world also have become increasingly concerned that immunosuppressed patients including those with autoimmune diseases may be at increased risk for developing Coronavirus Disease 2019 (COVID-19) with serious complications. Very little is known about how anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis modifies the susceptibility, clinical presentation and disease course of COVID-19. In this review, we discuss the mechanism of action and challenges of the current therapeutic armamentarium of ANCA-associated vasculitis and outline approaches to management of ANCA-associated vasculitis during the COVID-19 pandemic. [ABSTRACT FROM AUTHOR]

The prognosis of patients with ANCA-associated vasculitis has improved over the past decades, but overall survival rates are still unsatisfactory. Recent research has focused on complications of immunosuppressive measures and comorbidities of ANCA-associated vasculitis. This review focuses on thromboembolic and cardiovascular events. A considerably increased risk of thromboembolic events has been reported, which is associated with active disease and impaired coagulation factors. There is mounting evidence that a hypercoagulable state is present even in patients in remission, and studies investigating the impact of tailored anticoagulation are needed to reduce the burden of thromboembolism. Cardiovascular mortality is one of the leading causes of death and accelerated atherosclerosis is frequently observed in patients with ANCA-associated vasculitis. A high frequency of patients develops hypertension, diabetes mellitus and hypercholesterolaemia, either as a consequence of immunosuppression or associated with the underlying disease. The current control of modifiable cardiovascular risk factors is insufficient and thorough reviews should be performed periodically. Treatment of these risk factors should be adopted according to current recommendations related to individual cardiovascular risk prediction. [ABSTRACT FROM AUTHOR]

Objective: To assess the frequency of venous thromboembolism (VTE) events in the Rituximab in Antineutrophil Cytoplasmic Antibody (ANCA)–Associated Vasculitis (RAVE) trial and identify novel potential risk factors. Methods: VTE events in 197 patients enrolled in the RAVE trial were analyzed. Baseline demographic and clinical characteristics were recorded, and univariate and multivariate analyses were performed to identify factors associated with VTE in ANCA‐associated vasculitis (AAV). Results: VTE occurred in 16 patients (8.1%) with an overall average time to event of 1.5 months (range 1.0–2.75). In univariate analyses with calculation of hazard ratios (HRs) and 95% confidence intervals (95% CIs), heart involvement (HR 17.408 [95% CI 2.247–134.842]; P = 0.006), positive proteinase 3 (PR3)–ANCA (HR 7.731 [95% CI 1.021–58.545]; P = 0.048), pulmonary hemorrhage (HR 3.889 [95% CI 1.448–10.448]; P = 0.008), and the presence of red blood cell casts (HR 15.617 [95% CI 3.491–69.854]; P < 0.001) were associated with the onset of VTE. In multivariate models adjusted for age and sex, the significant associations between VTE events and heart involvement (HR 21.836 [95% CI 2.566–185.805]; P = 0.005), PR3‐ANCA (HR 9.12 [95% CI 1.158–71.839]; P = 0.036), pulmonary hemorrhage (HR 3.91 [95% CI 1.453–10.522]; P = 0.007), and urinary red blood cell casts (HR 16.455 [95% CI 3.607–75.075]; P < 0.001) remained. Conclusion: Patients diagnosed as having AAV with pulmonary hemorrhage, positive PR3‐ANCA, heart involvement, and the presence of red blood cell casts are at an increased risk to develop VTE. Further studies are needed to confirm and expand these findings and to explore the mechanisms of hypercoagulability in these patients with the aim of informing potential targets for therapeutic intervention. [ABSTRACT FROM AUTHOR]

The authors discuss a report on the description of clinical features and disease course of orbital masses in ANCA-associated vasculitis (AAV). Topics discussed include factors predicting the onset of orbital masses in the context of AAV, a diagnostic pathway to minimize diagnostic delay and improve the management of subset of patients, and comparison of first-line treatment of a cyclophosphamide- to a rituximab-based regimen.

Objective. To assess potential associations for the development of venous thromboembolic events in patients with ANCA-associated vasculitides (AAV). Methods. Four hundred and seventeen patients enrolled to participate in randomized controlled trials conducted by the European Vasculitis Society were identified. Univariate and multivariate analyses were performed to validate previously proposed and identify novel risks associated with venous thromboembol-ism (VTE) in AAV. Results. VTE occurred in 41 of 417 (9.8%) patients. Uncorrected univariate analysis identified BVAS (odds ratio, OR = 1.05, 95% CI: 1.01, 1.10; P = 0.013), subsequent development of malignancy (OR = 2.6, 95% CI: 1.19, 5.71; P = 0.017), mucous membrane or eye involvement (OR = 2.13, 95% CI: 1.10, 4.11; P = 0.024) and baseline creatinine (OR = 1.08, 95% CI: 0.99, 1.18; P = 0.037) as being associated with the development of VTE. Multivariate analysis highlighted CRP (per 10mg/l increase, OR = 1.05, 95% CI: 1.01, 1.09; P = 0.025), cutaneous involvement (OR = 4.83, 95% CI: 1.63, 14.38; P = 0.005) and gastrointestinal involvement (OR = 6.27, 95% CI: 1.34, 29.37; P = 0.02) among the BVAS items as well as baseline creatinine (per 100 mmol/l increase, OR = 1.17, 95% CI: 1.02, 1.35; P = 0.029) as being associated with VTEs. Conclusion. Our results highlight a role of CRP, baseline creatinine, and cutaneous and gastrointestinal involvement in the risk stratification as being associated with thromboembolic events. Moreover, there might be an association between VTEs and subsequent development of malignancy and disease activity in general. [ABSTRACT FROM AUTHOR]

Background. Studies in anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV) have revealed promising biomarkers. The aim of our study was to validate the most encouraging markers of granulomatosis with polyangiitis and microscopic polyangiitis identified by literature search and to create biomarker panels. Methods. A systematic literature review was performed and we identified 161 marker molecules that were ranked by their quantitative differential expression between active and inactive disease. Enzyme-linked immunosorbent assays were used to validate the results in a cross-sectional cohort of patients with renal involvement. Active vasculitis as assessed by the Birmingham Vasculitis Score version 3 (BVAS v3) was defined as BVAS v3 ≥1 and inactive disease as BVAS v3 = 0. Statistical analysis was performed with SPSS version 21 and the Salford Predictive Modeler 7.0 was used to generate a predictive biomarker panel. Results. The review indicated abundant expression of sC5bC9, C3a, C5a and monocyte chemotactic protein (MCP)-1 in urine, whereas granulocyte macrophage colony-stimulating factor, Creactive protein (CRP), soluble fms-like tyrosine kinase-1, interleukin-17A (IL-17A), C5a, hyaluronan, C3a and interleukin- 18 binding protein (IL-18BP) were identified to be highly diverse in active and inactive disease in blood samples. Our cross-sectional analysis revealed significant up-regulation of CRP, C5a, C3a, IL-18BP in blood and C5a and MCP-1 in urine samples during active AAV (all P < 0.05). Creation of a biomarker panel comprising CRP and urinary MCP-1 yielded a sensitivity and specificity of 76% (area under the curve 0.89). Conclusions. We identified promising biomarkers in a literature- based review that were in part corroborated as has been shown for CRP, C3a, C5a, IL-18BP in blood and MCP-1 and C5a in urine samples. Moreover, we propose a biomarker panel comprising CRP and urinary MCP-1 in patients with AAV and renal involvement. Further investigations to confirm our preliminary results are clearly warranted, including the reliability to predict disease relapses. [ABSTRACT FROM AUTHOR]

Rituximab has enriched our armamentarium in the treatment of anti-neutrophil cytoplasmic antibody (ANCA)- associated vasculitis. Two randomised controlled trials have shown that rituximab is non-inferior compared with cyclophosphamide followed by azathioprine for the induction of remission. The newly diagnosed patients in the Rituximab in ANCA-Associated Vasculitis (RAVE) and Rituximab Versus Cyclophosphamide in ANCA-Associated Vasculitis (RITUXVAS) trials had a numerically higher response rate in the cyclophosphamide/azathioprine arm, and the number of such patients treated with rituximab numbered <90.We are arguing that in newly diagnosed patients, the evidence for rituximab requires further confirmation and the length of experience with a cyclophosphamide-based induction therapy supports it continuing as the preferred first choice for induction. Also, there is an absence of information regarding rituximab as 'sole' remission induction along with steroids in patients with advanced renal presentations or lung haemorrhage. Reported side effects were similar in both trials; however, the number of participants with at least one serious adverse event following rituximab induction treatment was numerically higher in the RAVE trial. In addition, hypogammaglobulinaemia with the need of substitution in some cases and late-onset neutropaenia are complications not seen with cyclophosphamide. Over the longer term it is unclear what relapse prevention strategy should be employed after rituximab, and there was a trend to a higher relapse risk after rituximab in the RITUXVAS trial at 2 years. Further health economic studies are required to understand all the costs associated with rituximab. In the context of concomitant underlying infectious complications, in terms of fertility concerns, especially in young patients, and when malignancy is underlying we would recommend the use of rituximab as first-line therapy. [ABSTRACT FROM AUTHOR]

Background Antineutrophil cytoplasm antibody (ANCA)-associated vasculitides are potentially life-threatening disorders. Materials and methods Even though immunosuppressive therapy improves the prognosis, adverse events, either attributable to persistent disease activity or side effects of treatment remain a challenge. Infectious complications are the leading cause of death in the first year after diagnosis and a major cause of morbidity and mortality thereafter. Results Their incidence in clinical trials varies considerably but opportunistic and life-threatening infections, such as Pneumocystis jirovecii pneumonia or systemic cytomegalovirus infections, are frequent and thus predisposing/risk factors need to be defined. Pneumocystis jirovecii pneumonia has been associated with a lymphocyte count below 300/mm3. Additionally, besides the aggressiveness of the immunosuppressive regimen administered (especially the cumulative dose of steroids and cyclophosphamide), an elevated serum creatinine or dialysis dependency, older age and pulmonary involvement increase the rate of infectious complications. Conclusions We suggest to routinely prescribe trimethoprim-sulfamethoxazole or antimicrobial agents such as pentamidine in case of intolerance or contraindication in the early phase of induction therapy irrespective of the immunosuppressive strategy used and to continue therapy, together with other targeted measures (antiviral, antimycotic or antibiotic) in the presence of risk factors for a prolonged period of time. Finally, there is an urgent need to standardize the reporting of infectious complications in clinical trials to enable comparing the adverse event spectrum of distinct treatment approaches more appropriately. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective Data on ANCA-associated vasculitis (AAV) induced by anti-thyroid drugs (ATD) are scarce. We aimed to describe the characteristics and outcome of these patients in comparison to primary AAV. Methods We performed a retrospective multicentre study including patients with ATD-induced AAV. We focused on ATD-induced microscopic polyangiitis (MPA) and compared them with primary MPA by matching each case with four controls by gender and year of diagnosis. Results Forty-five patients with ATD-induced AAV of whom 24 MPA were included. ANCA were positive in 44 patients (98%), including myeloperoxidase (MPO)-ANCA in 21 (47%), proteinase 3 (PR3)-ANCA in six (13%), and double positive MPO- and PR3-ANCA in 15 (33%). Main clinical manifestations were skin involvement (64%), arthralgia (51%) and glomerulonephritis (20%). ATD was discontinued in 98% of cases, allowing vasculitis remission in seven (16%). All the remaining patients achieved remission after glucocorticoids, in combination with rituximab in 11 (30%) or cyclophosphamide in four (11%). ATD were reintroduced in seven cases (16%) without any subsequent relapse. Compared with 96 matched primary MPA, ATD-induced MPA were younger at diagnosis (48 vs 65 years, P  < 0.001), had more frequent cutaneous involvement (54 vs 25%, P  = 0.007), but less frequent kidney (38 vs 73%, P  = 0.02), and a lower risk of relapse (adjusted HR 0.07; 95% CI 0.01, 0.65, P  = 0.019). Conclusion ATD-induced AAV were mainly MPA with MPO-ANCA, but double MPO- and PR3-ANCA positivity was frequent. The most common manifestations were skin and musculoskeletal manifestations. ATD-induced MPA were less severe and showed a lower risk of relapse than primary MPA. [ABSTRACT FROM AUTHOR]

A number of genome-wide association studies (GWASs) and meta-analyses of genetic variants have been performed in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. We reinterpreted previous studies using false-positive report probability (FPRP) and Bayesian false discovery probability (BFDP). This study searched publications in PubMed and Excerpta Medica Database (EMBASE) up to February 2018. Identification of noteworthy associations were analyzed using FPRP and BFDP, and data (i.e., odds ratio (OR), 95% confidence interval (CI), p-value) related to significant associations were separately extracted. Using filtered gene variants, gene ontology (GO) enrichment analysis and protein–protein interaction (PPI) networks were performed. Overall, 241 articles were identified, and 7 were selected for analysis. Single nucleotide polymorphisms (SNPs) discovered by GWASs were shown to be noteworthy, whereas only 27% of significant results from meta-analyses of observational studies were noteworthy. Eighty-five percent of SNPs with borderline p-values (5.0 × 10−8 < p < 0.05) in GWASs were found to be noteworthy. No overlapping SNPs were found between PR3-ANCA and MPO-ANCA vasculitis. GO analysis revealed immune-related GO terms, including "antigen processing and presentation of peptide or polysaccharide antigen via major histocompatibility complex (MHC) class II", "interferon-gamma-mediated (IFN-γ) signaling pathway". By using FPRP and BFDP, network analysis of noteworthy genetic variants discovered genetic risk factors associated with the IFN-γ pathway as novel mechanisms potentially implicated in the complex pathogenesis of ANCA-associated vasculitis. [ABSTRACT FROM AUTHOR]

Updated guidelines on the management of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) were released in 2021 by the American College of Rheumatology jointly with the Vasculitis Foundation and, subsequently, in 2022 by the European Alliance of Associations for Rheumatology. In addition, in 2021, the Kidney Disease: Improving Global Outcomes had released updated recommendations on the treatment of AAV with glomerulonephritis (AAV-GN). Kidney involvement is particularly relevant in microscopic polyangiitis and granulomatosis with polyangiitis, but is less frequent in eosinophilic granulomatosis with polyangiitis. The management of AAV-GN has been a focus for drug development and change over the past 10 years. Avoidance of progression to end-stage kidney disease (ESKD) or kidney failure is one of the main unmet needs in the management of AAV, with ESKD having a major impact on morbidity, health costs and mortality risk. Relevant changes in AAV-GN management are related to remission-induction treatment of patients with severe kidney disease, the use of glucocorticoids and avacopan, and remission-maintenance treatment. All the documents provide guidance in accordance with the evidence-based standard of care available at the time of their release. With our work we aim to (i) show the progress made and identify the differences between guidelines and recommendations, (ii) discuss the supporting rationale for those, and (iii) identify gaps in knowledge that could benefit from additional research and should be revised in subsequent updates. [ABSTRACT FROM AUTHOR]

Avoiding end-stage kidney disease in patients with anti-neutrophil cytoplasmic antibody–associated vasculitis (AAV) has a high therapeutic priority. Although renal response is a crucial measure to capture clinically relevant changes, clinal trials have used various definitions and no well-studied key surrogate markers to predict renal outcome in AAV exist. Differences in clinical features and histopathologic and therapeutic approaches will influence the course of kidney function. Its assessment through traditional surrogates (i.e. serum creatinine, glomerular filtration rate, proteinuria, hematuria and disease activity scores) has limitations. Refinement of these markers and the incorporation of novel approaches such as the assessment of histopathological changes using cutting-edge molecular and machine learning mechanisms or new biomarkers could significantly improve prognostication. The timing is favourable since large datasets of trials conducted in AAV are available and provide a valuable resource to establish renal surrogate markers and, likely, aim to investigate optimized and tailored treatment approaches according to a renal response score. In this review we discuss important points missed in the assessment of kidney function in patients with AAV and point towards the importance of defining renal response and clinically important short- and long-term predictors of renal outcome. [ABSTRACT FROM AUTHOR]

The approval of avacopan as a treatment for anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) by the US Food and Drug Administration (FDA) in 2021 and the European Medicines Agency (EMA) in 2022 represents an important therapeutic advance. Of the patients receiving avacopan, 13.3% suffered serious infections versus 15.2% in those in the prednisone group, and serious opportunistic infections were less common in patients receiving avacopan (3.6% in the avacopan group, 6.7% in the prednisone group) [[10]]. Insights from the ADVOCATE study: respiratory tract involvement in patients with ANCA-associated vasculitis in a randomized, double-blind, placebo-controlled, phase 3 trial of avacopan. Recovery of renal function among ANCA-associated vasculitis patients with baseline eGFR <=20 in the avacopan ADVOCATE trial. [Extracted from the article]

Objective: To develop and validate new classification criteria for Takayasu arteritis (TAK). Methods: Patients with vasculitis or comparator diseases were recruited into an international cohort. The study proceeded in 6 phases: 1) identification of candidate criteria items, 2) collection of candidate items present at diagnosis, 3) expert panel review of cases, 4) data‐driven reduction of candidate items, 5) derivation of a points‐based classification score in a development data set, and 6) validation in an independent data set. Results: The development data set consisted of 316 cases of TAK and 323 comparators. The validation data set consisted of an additional 146 cases of TAK and 127 comparators. Age ≤60 years at diagnosis and imaging evidence of large‐vessel vasculitis were absolute requirements to classify a patient as having TAK. The final criteria items and weights were as follows: female sex (+1), angina (+2), limb claudication (+2), arterial bruit (+2), reduced upper extremity pulse (+2), reduced pulse or tenderness of a carotid artery (+2), blood pressure difference between arms of ≥20 mm Hg (+1), number of affected arterial territories (+1 to +3), paired artery involvement (+1), and abdominal aorta plus renal or mesenteric involvement (+3). A patient could be classified as having TAK with a cumulative score of ≥5 points. When these criteria were tested in the validation data set, the model area under the curve was 0.97 (95% confidence interval [95% CI] 0.94–0.99) with a sensitivity of 93.8% (95% CI 88.6–97.1%) and specificity of 99.2% (95% CI 96.7–100.0%). Conclusion: The 2022 American College of Rheumatology/EULAR classification criteria for TAK are now validated for use in research. [ABSTRACT FROM AUTHOR]

Background Uncertainties exist about the use of mycophenolate mofetil (MMF) in anti-neutrophil cytoplasmatic antibody (ANCA)-associated vasculitis (AAV), particularly for remission maintenance. Methods Systematic review and meta-analysis of phase II and III trials assessing the use of MMF in AAV, granulomatosis with polyangiitis and microscopic polyangiitis (MPA). A comprehensive search of several databases (Medline, EMBASE, Cochrane, Web of Science, Scopus) from inception to 5 May 2020 has been conducted. Trial data were extracted to estimate odds ratios (ORs) and estimates (ES) for MMF efficacy (remission-induction and maintenance). Severe adverse effects (SAEs) were collected. Results From 565 articles captured, 10 met the predefined criteria, 5 phase II and 5 III trials; 4 assessed remission-induction, 3 remission maintenance and 3 both. The pooled OR for remission-induction at 6 months was 1.06 (95% confidence interval 0.74, 1.52), with no significant difference by subgroup meta-analysis of trials stratified by different study-level features (i.e. kidney disease, MPA, myeloperoxidase-ANCA positivity, newly diagnosed disease) (P > 0.05). The overall ES for remission maintenance at the end of follow-up ranged between 51% and 91% (I2 = 74.8%). Subgroup meta-analysis identified kidney involvement as a possible source of heterogeneity, yielding a significantly higher rate of sustained remission in trials enrolling only patients with kidney involvement (92%, 76–100%) versus those enrolling patients with and without kidney involvement (56%, 45–66%). Results were similar in multiple sensitivity analyses. During follow-up, the frequency of SAEs in MMF-based treatment arms was 31.8%. Conclusions In AAV, MMF use was significantly associated with higher sustained remission rates in trials enrolling only patients with kidney involvement. These findings might influence clinical practice. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Patients with immune-mediated kidney diseases are at increased risk of severe coronavirus disease 2019 (COVID-19). The international rollout of COVID-19 vaccines has provided varying degrees of protection and enabled the understanding of vaccine efficacy and safety. The immune response to COVID-19 vaccines is lower in most patients with immune-mediated kidney diseases; either related to immunosuppression or comorbidities and complications caused by the underlying disease. Humoral vaccine response, measured by the presence of antibodies, is impaired or absent in patients receiving rituximab, mycophenolate mofetil (MMF), higher doses of glucocorticoids and likely other immunosuppressants, such as cyclophosphamide. The timing between the use of these agents and administration of vaccines is associated with the level of immune response: with rituximab, vaccine response can only be expected once B cells start to recover and patients with transient discontinuation of MMF mount a humoral response more frequently. The emergence of new COVID-19 variants and waning of vaccine-induced immunity highlight the value of a booster dose and the need to develop mutant-proof vaccines. COVID-19 vaccines are safe, exhibiting a very low risk of de novo or relapsing immune-mediated kidney disease. Population-based studies will determine whether this is causal or coincidental. Such cases respond to standard management, including the use of immunosuppression. The Immunonephrology Working Group and European Vasculitis Society recommend that patients with immune-mediated kidney diseases follow national guidance on vaccination. Booster doses based on antibody measurements could be considered. [ABSTRACT FROM AUTHOR]

Objective: To develop and validate classification criteria for microscopic polyangiitis (MPA). Methods: Patients with vasculitis or comparator diseases were recruited into an international cohort. The study proceeded in 5 phases: 1) identification of candidate items using consensus methodology, 2) prospective collection of candidate items present at the time of diagnosis, 3) data‐driven reduction of the number of candidate items, 4) expert panel review of cases to define the reference diagnosis, and 5) derivation of a points‐based risk score for disease classification in a development set using least absolute shrinkage and selection operator logistic regression, with subsequent validation of performance characteristics in an independent set of cases and comparators. Results: The development set for MPA consisted of 149 cases of MPA and 408 comparators. The validation set consisted of an additional 142 cases of MPA and 414 comparators. From 91 candidate items, regression analysis identified 10 items for MPA, 6 of which were retained. The final criteria and their weights were as follows: perinuclear antineutrophil cytoplasmic antibody (ANCA) or anti–myeloperoxidase‐ANCA positivity (+6), pauci‐immune glomerulonephritis (+3), lung fibrosis or interstitial lung disease (+3), sino‐nasal symptoms or signs (−3), cytoplasmic ANCA or anti–proteinase 3 ANCA positivity (−1), and eosinophil count ≥1 × 109/liter (−4). After excluding mimics of vasculitis, a patient with a diagnosis of small‐ or medium‐vessel vasculitis could be classified as having MPA with a cumulative score of ≥5 points. When these criteria were tested in the validation data set, the sensitivity was 91% (95% confidence interval [95% CI] 85–95%) and the specificity was 94% (95% CI 92–96%). Conclusion: The 2022 American College of Rheumatology/European Alliance of Associations for Rheumatology classification criteria for MPA are now validated for use in clinical research. [ABSTRACT FROM AUTHOR]

Objective Atypical manifestations have been described in patients with ANCA-associated vasculitides (AAV), such as pachymeningitis, orbital mass or chronic periaortitis. Because these manifestations have been associated to the spectrum of IgG4-related disease (IgG4-RD), we hypothesized that both diseases could overlap. Methods We conducted a European retrospective multicenter observational study including patients fulfilling ACR and Chapel Hill criteria for AAV and IgG4-RD Comprehensive Diagnostic Criteria. Results Eighteen patients were included (median age 55.5 years, 13 men). AAV and IgG4-RD were diagnosed concomitantly in 13/18 (72%) patients; AAV preceded IgG4-RD in 3/18 (17%) while IgG4-RD preceded AAV in 2/18 (11%). AAV diagnoses included granulomatosis with polyangiitis in 14 (78%), microscopic polyangiitis in 3 (17%), and eosinophilic granulomatosis with polyangiitis in one case. IgG4-RD diagnosis included definite IgG4-RD in 5 (28%) cases, probable IgG4-RD in 5 (28%) and possible IgG4-RD in 8 (44%). IgG4-RD manifestations were chronic periaortitis in 9/18 (50%) patients, orbital mass and tubulointerstitial nephritis in 4 (22%) cases, prevertebral fibrosis in 3 (17%), pachymeningitis and autoimmune pancreatitis in 2 (11%) cases. Patients required median number of 2 (range 0–4) lines of immunosuppressants in combination with glucocorticoids. During the follow-up (median 49,8 months, range 17,25–108 months), AAV manifestations relapsed in 10/18 (56%) cases and IgG4-RD lesions in 5/18 (28%). When used, mainly for relapses, rituximab showed response in all cases. Conclusion AAV and IgG4-RD may overlap. Clinicians should consider that atypical manifestations during AAV could be related to IgG4-RD rather than to refractory granulomatous or vasculitic lesions. [ABSTRACT FROM AUTHOR]

Peripheral blood eosinophilia (PBE), defined as 500 eosinophils or above per microliter (µL) blood, is a condition that is not uncommon but often neglected in the management of patients with chronic kidney disease (CKD), acute kidney injury (AKI), or patients on renal replacement therapy (RRT). The nature of PBE in the context of kidney diseases is predominantly secondary or reactive and has to be distinguished from primary eosinophilic disorders. Nonetheless, the finding of persistent PBE can be a useful clue for the differential diagnosis of underdiagnosed entities and overlapping syndromes, such as eosinophilic granulomatosis with polyangiitis (EGPA), IgG4-related disease (IgG4-RD), acute interstitial nephritis (AIN), or the hypereosinophilic syndrome (HES). For patients on RRT, PBE may be an indicator for bio-incompatibility of the dialysis material, acute allograft rejection, or Strongyloides hyperinfection. In a subset of patients with EGPA, eosinophils might even be the driving force in disease pathogenesis. This improved understanding is already being used to facilitate novel therapeutic options. Mepolizumab has been licensed for the management of EGPA and is applied with the aim to abrogate the underlying immunologic process by blocking interleukin-5. The current article provides an overview of different renal pathologies that are associated with PBE. Further scientific effort is required to understand the exact role and function of eosinophils in these disorders which may pave the way to improved interdisciplinary management of such patients. [ABSTRACT FROM AUTHOR]