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Proteinase 3 (PR3) is the major antigen for anti-neutrophil cytoplasmic antibodies (ANCAs) in the systemic autoimmune vasculitis, granulomatosis with polyangiitis (GPA). PR3 anti-neutrophil cytoplasmic antibodies (PR3-ANCAs) recognize different epitopes on PR3. We aimed to study the effect of mutations on PR3 antigenicity.The recombinant PR3 variants, iPR3 (clinically used to detect PR3-ANCAs) and iHm5 (containing three point mutations in Epitope 15 generated for epitope mapping studies, immunoassays and serum samples from patients enrolled in ANCA-associated vasculitis (AAV) trials were used to screen the differential PR3-ANCA binding. A patient-derived monoclonal ANCA (moANCA518) that selectively binds to iHm5 within the mutation-free Epitope 3 and distant from the point mutations of iHm5 was used as a gauge of remote epitope activation. Selective binding was determined by inhibition experiments.Rather than reduced binding of PR3-ANCAs to iHm5, we found substantially increased binding of the majority of PR3-ANCAs to iHm5 compared with iPR3. This differential binding of PR3-ANCA to iHm5 is similar to the selective moANCA518 binding to iHm5. Binding of iPR3 to monoclonal antibody MCPR3-2 also induced recognition by moANCA518.The preferential binding of PR3-ANCAs from patients like the selective binding of moANCA518 to iHm5 is conferred by increased antigenicity of Epitope 3 on iHm5. This can also be induced on iPR3 when captured by monoclonal antibody MCPR-2. This previously unrecognized characteristic of PR3-ANCA interactions with its target antigen has implications for studying antibody-mediated autoimmune diseases, understanding of variable performance characteristics of immunoassays and design of potential novel treatment approaches. This article is protected by copyright. All rights reserved.

© Published by Oxford University Press on behalf of the British Society for Rheumatology 2022. This work is written by US Government employees and is in the public domain in the US., Objectives: To assess whether data from 18F-fluorodeoxyglucose (FDG) PET should be incorporated into eligibility criteria for clinical trials in Takayasu's arteritis (TAK). Methods: The study was conducted in two parts. Part one was an international online survey among physicians with experience managing TAK to determine, using clinical vignettes, whether FDG-PET data influence decisions about enrolment in trials. Part two used patient data from an observational cohort study in TAK to assess agreement regarding decisions about enrolment into trials, based on clinical assessment with and without incorporation of FDG-PET data. Results: In part one, 68 physicians responded to the survey. Most physicians had used FDG-PET to diagnose TAK (82%) or monitor disease activity (66%). In vignettes representing active clinical disease, FDG-PET findings increased physician confidence in disease assessment and reduced outlier assessments. The greatest variability in decisions regarding enrolment into trials was observed in vignettes representing constitutional symptoms alone and elevated acute-phase reactants. In these cases, FDG-PET findings influenced decisions about enrolment and improved physician confidence. In multivariable models, FDG-PET findings were 1.29 times more strongly associated with enrolment decisions compared with levels of acute-phase reactants. In part two, incorporation of FDG-PET data significantly improved agreement about enrolment decisions between raters [inter-rater reliability (IRR) = 0.68 (95% CI 0.67, 0.69) to IRR = 0.88 (95% CI 0.87, 0.89); P < 0.01]. Conclusions: Incorporation of FDG-PET data into assessment of TAK influences decisions about enrolment of patients into trials, improves physician confidence about clinical assessment and could help reduce variability in study populations. Future trials in TAK should consider incorporating FDG-PET data into eligibility criteria.

Objectives Rituximab is a standard of care therapy for patients with ANCA-associated vasculitis. When rituximab is contraindicated, or in the case of refractory disease, other treatments are needed. Obinutuzumab is another anti-CD20 antibody for the treatment of haematological malignancies that may induce a deeper B cell depletion compared with rituximab. This article reviews three cases of patients with ANCA-associated vasculitis who were treated with obinutuzumab due to their history of anaphylactic reactions to rituximab. Methods Case series of three patients with ANCA-associated vasculitis treated with obinutuzumab. Results One female patient with microscopic polyangiitis and two male patients with granulomatosis with polyangiitis received obinutuzumab. The treatment was well-tolerated in all patients despite previous anaphylactic reaction to rituximab. Treatment with obinutuzumab was effective in (i) inducing disease remission, (ii) inducing total B cell depletion, and (iii) resulting in undetectable serum titres of ANCA. All three patients were re-treated with obinutuzumab for maintenance of remission. Conclusion Obinutuzumab appears to be a safe and efficacious therapy for patients with ANCA-associated vasculitis who have had refractory disease or a history of anaphylaxis to rituximab. Prospective studies comparing rituximab to obinutuzumab in ANCA-associated vasculitis patients are warranted.

Objective To study the prevalence, risk and clinical associations of hypothyroidism among several forms of vasculitis. Methods Patients with GCA, Takayasu’s arteritis (TAK), PAN and the three forms of ANCA-associated vasculitis [AAV; granulomatosis with polyangiitis (GPA), microscopic polyangiitis and eosinophilic granulomatosis with polyangiitis (EGPA)] enrolled in a prospective, multicentre, longitudinal study were included. Results The study included data on 2085 patients [63% female, 90% White] with a mean age of 54.6 years (s.d. 17.2). Diagnoses were GCA (20%), TAK (11%), PAN (5%), GPA (42%), microscopic polyangiitis (8%) and EGPA (14%). Hypothyroidism was present in 217 patients (10%) (83% female), with a mean age 59.8 years (s.d. 14.5). Age- and sex-adjusted risk of hypothyroidism was GCA, odds ratio (OR) 0.61 (95% CI 0.41, 0.90); TAK, OR 0.57 (95% CI 0.31, 1.03); PAN, OR 0.59 (95% CI 0.25, 1.38); GPA, OR 1.51 (95% CI 1.12, 2.05); microscopic polyangiitis, OR 1.81 (95% CI 1.18, 2.80) and EGPA, OR 0.82 (95% CI 0.52, 1.30). Among patients with AAV, age- and sex-adjusted risk of hypothyroidism was higher with positive MPO-ANCA [OR 1.89 (95% CI 1.39, 2.76)]. The clinical manifestations of vasculitis were similar in patients with and without hypothyroidism, except transient ischaemic attacks, which were more frequently observed in patients with GCA and hypothyroidism (12% vs 2%; P = 0.001). Conclusions Differences in the risk of hypothyroidism among vasculitides may be due to genetic susceptibilities or immune responses. This study confirms an association of hypothyroidism with MPO-ANCA.

Objectives ANCA-associated vasculitis (AAV) is a group of multisystem diseases that can have several ocular manifestations. There are published data on ocular manifestations of granulomatosis with polyangiitis (GPA), but few for eosinophilic granulomatosis with polyangiitis (EGPA) or microscopic polyangiitis (MPA). There is little information concerning chronicity, complications, and association with other cranial manifestations of AAV. Methods This study retrospectively analysed longitudinal multicentre cohorts of individuals with AAV followed between 2006 and 2022. Data included diagnosis, demographics, cranial manifestations of disease, presence of manifestations at onset of disease and/or follow-up, and ocular complications of disease. Univariate and multivariable logistic regression analysis assessed associations across disease manifestations. Results Data from 1441 patients were analysed, including 395 with EGPA, 876 with GPA, and 170 with MPA. Ocular manifestations were seen within 23.1% of patients: 39 (9.9%) with EGPA, 287 (32.7%) with GPA, and 12 (7.1%) with MPA at any time in the disease course. There were more ocular manifestations at onset (n = 224) than during follow-up (n = 120). The most common disease-related manifestations were conjunctivitis/episcleritis and scleritis. In multivariable analysis, dacryocystitis, lacrimal duct obstruction, and retro-orbital disease were associated with sinonasal manifestations of GPA; ocular manifestations were associated with hearing loss in MPA. The most common ocular complications and/or damage seen were cataracts (n = 168) and visual impairment (n = 195). Conclusion Ocular manifestations occur in all forms of AAV, especially in GPA. Clinicians should be mindful of the wide spectrum of ocular disease in AAV, caused by active vasculitis, disease-associated damage, and toxicities of therapy.

Autoreactive B cells are responsible for ANCA production in ANCA-associated vasculitis (AAV). Rituximab depletes circulating B cells including autoreactive ones. We aimed to evaluate changes and associations with relapse of the circulating autoreactive B cell pool following therapeutic B cell depletion in AAV.Sequential flow-cytometry was performed on 148 samples of peripheral blood mononuclear cells from 23 proteinase-3 (PR3)-ANCAAt B cell recurrence, PR3The composition of autoreactive B cell pool varies significantly following rituximab treatment in AAV, and early plasmablast enrichment within the autoreactive pool is associated with future relapses.

Objective To provide evidence-based recommendations and expert guidance for the management of antineutrophil cytoplasmic antibody-associated vasculitis (AAV), including granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). Methods Clinical questions regarding the treatment and management of AAV were developed in the population, intervention, comparator, and outcome (PICO) format (47 for GPA/MPA, 34 for EGPA). Systematic literature reviews were conducted for each PICO question. The Grading of Recommendations Assessment, Development and Evaluation methodology was used to assess the quality of evidence and formulate recommendations. Each recommendation required ≥70% consensus among the Voting Panel. Results We present 26 recommendations and 5 ungraded position statements for GPA/MPA, and 15 recommendations and 5 ungraded position statements for EGPA. This guideline provides recommendations for remission induction and maintenance therapy as well as adjunctive treatment strategies in GPA, MPA, and EGPA. These recommendations include the use of rituximab for remission induction and maintenance in severe GPA and MPA and the use of mepolizumab in nonsevere EGPA. All recommendations are conditional due in part to the lack of multiple randomized controlled trials and/or low-quality evidence supporting the recommendations. Conclusion This guideline presents the first recommendations endorsed by the American College of Rheumatology and the Vasculitis Foundation for the management of AAV and provides guidance to health care professionals on how to treat these diseases.

Objective To provide evidence-based recommendations and expert guidance for the management of giant cell arteritis (GCA) and Takayasu arteritis (TAK) as exemplars of large vessel vasculitis. Methods Clinical questions regarding diagnostic testing, treatment, and management were developed in the population, intervention, comparator, and outcome (PICO) format for GCA and TAK (27 for GCA, 27 for TAK). Systematic literature reviews were conducted for each PICO question. The Grading of Recommendations Assessment, Development and Evaluation methodology was used to rate the quality of the evidence. Recommendations were developed by the Voting Panel, comprising adult and pediatric rheumatologists and patients. Each recommendation required ≥70% consensus among the Voting Panel. Results We present 22 recommendations and 2 ungraded position statements for GCA, and 20 recommendations and 1 ungraded position statement for TAK. These recommendations and statements address clinical questions relating to the use of diagnostic testing, including imaging, treatments, and surgical interventions in GCA and TAK. Recommendations for GCA include support for the use of glucocorticoid-sparing immunosuppressive agents and the use of imaging to identify large vessel involvement. Recommendations for TAK include the use of nonglucocorticoid immunosuppressive agents with glucocorticoids as initial therapy. There were only 2 strong recommendations; the remaining recommendations were conditional due to the low quality of evidence available for most PICO questions. Conclusion These recommendations provide guidance regarding the evaluation and management of patients with GCA and TAK, including diagnostic strategies, use of pharmacologic agents, and surgical interventions.

This systematic review compares treatment options for patients with giant cell arteritis (GCA) and evaluates the test accuracy of studies used in diagnosing and monitoring GCA. These studies were used to inform evidence‐based recommendations for the American College of Rheumatology (ACR)/Vasculitis Foundation (VF) vasculitis management guidelines. A systematic review and search of articles in English in Ovid Medline, PubMed, Embase, and the Cochrane Library was conducted. Articles were screened for suitability, and studies presenting the highest level of evidence were given preference. Three hundred ninety‐nine full‐text articles addressing GCA questions were reviewed to inform 27 Population, Intervention, Comparison, and Outcome questions. No benefit was found with intravenous glucocorticoids (GCs) compared with high‐dose oral GCs in patients with cranial ischemic symptoms (27.4% vs 12.3%; odds ratio [OR] 2.39 [95% confidence interval (CI) 0.75‐7.62], [very low certainty of evidence]). Weekly tocilizumab with a 26‐week GC taper was superior to a 52‐week GC taper in patients achieving remission (risk ratio 4.00 [95% CI 1.97‐8.12], [low certainty of evidence]). Non‐GC immunosuppressive therapies with GCs compared with GCs alone showed no statistically significant in relapse at 1 year (OR 0.87 [95% CI 0.73‐1.04], [moderate certainty of evidence]) or serious adverse events (OR 0.81 [95% CI 0.54‐1.20]; [moderate certainty of evidence]). Temporal artery biopsy has a sensitivity of 61% (95% CI 38%‐79%) and a specificity of 98% (95% CI 95%‐99%) in patients with a clinical diagnosis of suspected GCA. This comprehensive systematic review synthesizes and evaluates the benefits and harms of different treatment options and the accuracy of commonly used tests for the diagnosis and monitoring of GCA.

BackgroundThe frequency of proteinase 3 gene (PRTN3) polymorphisms in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is not fully characterised. We hypothesise that the presence of a PRTN3 gene polymorphism (single nucleotide polymorphism (SNP) rs351111) is relevant for clinical outcomes.MethodsDNA variant calling for SNP rs351111 (chr.19:844020, c.355G>A) in PRTN3 gene assessed the allelic frequency in patients with PR3-AAV included in the Rituximab in ANCA-Associated Vasculitis trial. This was followed by RNA-seq variant calling to characterise the mRNA expression. We compared clinical outcomes between patients homozygous for PRTN3-Ile119or PRTN3-Val119.ResultsWhole blood samples for DNA calling were available in 188 patients. 75 patients with PR3-AAV had the allelic variant: 62 heterozygous PRTN3-Val119Ile and 13 homozygous for PRTN3-Ile119. RNA-seq was available for 89 patients and mRNA corresponding to the allelic variant was found in 32 patients with PR3-AAV: 25 heterozygous PRTN3-Val119Ile and 7 homozygous for PRTN3-Ile119. The agreement between the DNA calling results and mRNA expression of the 86 patients analysed by both methods was 100%. We compared the clinical outcomes of 64 patients with PR3-AAV: 51 homozygous for PRTN3-Val119and 13 homozygous for PRTN3-Ile119. The frequency of severe flares at 18 months in homozygous PRTN3-Ile119was significantly higher when compared with homozygous PRTN3-Val119(46.2% vs 19.6%, p=0.048). Multivariate analysis identified homozygous PR3-Ile119as main predictor of severe relapse (HR 4.67, 95% CI 1.16 to 18.86, p=0.030).ConclusionIn patients with PR3-AAV, homozygosity for PRTN3-Val119Ile polymorphism appears associated with higher frequency of severe relapse. Further studies are necessary to better understand the association of this observation with the risk of severe relapse.

Objective The aim of this systemic review is to compare different treatments for patients with granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA) to inform evidence-based recommendations for the American College of Rheumatology (ACR)/Vasculitis Foundation (VF) Vasculitis Management Guidelines. Methods A systemic review was conducted by searching articles in English using OVID Medline, PubMed, Embase, and the Cochrane Library. Articles were screened for suitability in addressing PICO questions, with studies presenting the highest level of evidence given preference. Results A total of 729 full-text articles addressing GPA and MPA PICO questions were reviewed. For remission induction, rituximab was shown to be noninferior to cyclophosphamide (CYC) (odds ratio [OR]: 1.55, moderate certainty of evidence). The addition of plasma exchange to induction therapy in severe disease did not improve the composite end point of death or end stage renal disease (hazard ratio [HR]: 0.86 [95% confidence interval CI: 0.65, 1.13], moderate certainty of evidence). In nonsevere disease, methotrexate was noninferior to CYC for induction of remission (remission at 6 months of 90% vs. 94%). For maintenance of remission, methotrexate and azathioprine showed no difference in the risk of relapse over a mean follow-up of 29 months (HR: 0.92, [95% CI: 0.52, 1.65]low certainty of evidence). As maintenance therapy, rituximab was superior to a tapering azathioprine strategy in major relapse-free survival at 28 months (HR: 6.61, [95% CI: 1.56, 27.96], moderate certainty of evidence). In two randomized trials, longer-term azathioprine maintenance therapy (>24 months) is associated with fewer relapses without an increase in adverse events. Conclusion This comprehensive systematic review synthesizes and evaluates the benefits and toxicities of different treatment options for GPA and MPA.

OBJECTIVE. Deficiency of adenosine deaminase 2 (DADA2) is a monogenic form of vasculitis that can resemble polyarteritis nodosa (PAN). This study was undertaken to identify potential disease-causing sequence variants in ADA2 in patients with idiopathic PAN, granulomatosis with polyangiitis (GPA), or microscopic polyangiitis (MPA). METHODS. Patients with idiopathic PAN (n = 118) and patients with GPA or MPA (n = 1,107) were screened for rare nonsynonymous variants in ADA2 using DNA sequencing methods. ADA-2 enzyme activity was assessed in selected serum samples. RESULTS. Nine of 118 patients with PAN (7.6%) were identified as having rare nonsynonymous variants in ADA2. Four patients (3.4%) were biallelic for pathogenic or likely pathogenic variants, and 5 patients (4.2%) were monoallelic carriers for 3 variants of uncertain significance and 2 likely pathogenic variants. Serum samples from 2 patients with PAN with biallelic variants were available and showed markedly reduced ADA-2 enzyme activity. ADA-2 enzyme testing of 86 additional patients revealed 1 individual with strongly reduced ADA-2 activity without detectable pathogenic variants. Patients with PAN and biallelic variants in ADA2 were younger at diagnosis than patients with 1 or no variant in ADA2, with no other clinical differences noted. None of the patients with GPA or MPA carried biallelic variants in ADA2. CONCLUSION. A subset of patients with idiopathic PAN meet genetic criteria for DADA2. Given that tumor necrosis factor inhibition is efficacious in DADA2 but is not conventional therapy for PAN, these findings suggest that ADA-2 testing should strongly be considered in patients with hepatitis B virus–negative idiopathic PAN.

OBJECTIVE Eosinophilic granulomatosis with polyangiitis (EGPA) is part of a group of vasculitides commonly referred to as antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), in addition to granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and renal-limited vasculitis. Patients with EGPA characteristically have asthma and marked peripheral eosinophilia with only approximately 30% to 35% of patients being myeloperoxidase (MPO)-ANCA positive, distinguishing it from other forms of AAV (1,2). The aim of this systematic review is to support the development of the American College of Rheumatology/Vasculitis Foundation guideline for the management of EGPA. METHODS A systematic review was conducted of the literature for seven forms of primary systemic vasculitis (GPA, MPA, EGPA, polyarteritis nodosa, Kawasaki disease, giant cell arteritis, and Takayasu arteritis). The search was done for articles in English using Ovid Medline, PubMed, Embase, and the Cochrane Library. Articles were screened for suitability in addressing population/patients, intervention, comparator, and outcomes (PICO) questions, with studies presenting the highest level of evidence given preference. Two independent reviewers conducted a title/abstract screen and full-text review for each eligible study. RESULTS The initial search, conducted in August 2019, included 13 800 articles, of which 2596 full-text articles were reviewed. There were 190 articles (addressing 34 PICO questions) reporting on the diagnosis and management of EGPA. CONCLUSION This comprehensive systematic review synthesizes and evaluates the accuracy of commonly used tests for EGPA as well as benefits and toxicities of different treatment options.

Takayasu arteritis is a rare inflammatory disease of large arteries. We performed a genetic study in Takayasu arteritis comprising 6,670 individuals (1,226 affected individuals) from five different populations. We discovered HLA risk factors and four non-HLA susceptibility loci in VPS8, SVEP1, CFL2, and chr13q21 and reinforced IL12B, PTK2B, and chr21q22 as robust susceptibility loci shared across ancestries. Functional analysis proposed plausible underlying disease mechanisms and pinpointed ETS2 as a potential causal gene for chr21q22 association. We also identified >60 candidate loci with suggestive association (p < 5 x 10(-s)) and devised a genetic risk score for Takayasu arteritis. Takayasu arteritis was compared to hundreds of other traits, revealing the closest genetic relatedness to inflammatory bowel disease. Epigenetic patterns within risk loci suggest roles for monocytes and B cells in Takayasu arteritis. This work enhances understanding of the genetic basis and pathophysiology of Takayasu arteritis and provides clues for potential new therapeutic targets., National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of Arthritis & Musculoskeletal & Skin Diseases (NIAMS) [R01 AR070148]; National Institute of Arthritis and Musculoskeletal and Skin DiseasesUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of Arthritis & Musculoskeletal & Skin Diseases (NIAMS) [U54 AR057319, U01 AR51874 04]; National Center for Research ResourcesUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Center for Research Resources (NCRR) [U54 RR019497]; Office of Rare Diseases Research of the National Center for Advancing Translational Sciences; Imperial College, National Institute for Health Research, Biomedical Research Centre; Wellcome TrustWellcome TrustEuropean Commission [WT107881]; Medical Research CouncilUK Research & Innovation (UKRI)Medical Research Council UK (MRC)European Commission [MC_UU_00002/4], This work was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health grant R01 AR070148 to A.H.S. The Vasculitis Clinical Research Consortium has received support from the National Institute of Arthritis and Musculoskeletal and Skin Diseases (U54 AR057319 and U01 AR51874 04), the National Center for Research Resources (U54 RR019497), and the Office of Rare Diseases Research of the National Center for Advancing Translational Sciences. J.C.M., A.P.K., and R.M.M. acknowledge support from the Imperial College, National Institute for Health Research, Biomedical Research Centre. C.W. and G.R. acknowledge support from The Wellcome Trust (WT107881) and the Medical Research Council (MC_UU_00002/4). This work was supported by the use of study data downloaded from the dbGaP website, under dbGaP: phs000272.v1.p1, phs000431.v2.p1, phs000583.v1.p1, and phs000444.v1.p1.

ObjectivesWe investigated whether soluble immune checkpoints (sICPs) predict treatment resistance, relapse and infections in patients with antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV).MethodsPlasma sICP concentrations from available samples obtained during conduct of the RAVE trial were measured by immunoabsorbent assays from patients with either proteinase 3 (PR3) or myeloperoxidase (MPO)-ANCA vasculitis and were correlated with clinical outcomes, a set of biomarkers and available flow cytometry analyses focusing on T cell subsets. Log-rank test was used to evaluate survival benefits, and optimal cut-off values of the marker molecules were calculated using Yeldons J.ResultsAnalysis of 189 plasma samples at baseline revealed higher concentrations of sTim-3, sCD27, sLag-3, sPD-1 and sPD-L2 in patients with MPO-ANCA vasculitis (n=62) as compared with PR3-ANCA vasculitis (n=127). Among patients receiving rituximab induction therapy (n=95), the combination of lower soluble (s)Lag-3 (3000 pg/mL) predicted therapy failure. Twenty-four out of 73 patients (32.9%) in the rituximab arm reaching remission at 6 months relapsed during follow-up. In this subgroup, high baseline values of sTim-3 (>1200 pg/mL), sCD27 (>1250 pg/mL) and sBTLA (>1000 pg/mL) were associated with both sustained remission and infectious complications. These findings could not be replicated in 94 patients randomised to receive cyclophosphamide/azathioprine.ConclusionsPatients with AAV treated with rituximab achieved remission less frequently when concentrations of sLag-3 were low and concentrations of sCD27 were high. Higher concentrations of sTim-3, sCD27 and sBTLA at baseline predicted relapse in patients treated with rituximab. These results require confirmation but may contribute to a personalised treatment approach of AAV.

Takayasu's arteritis (TAK) is a clinically heterogenous disease. Patterns of clinical presentation in TAK at diagnosis have not been well described, and a "triphasic pattern" of constitutional symptoms evolving into vascular inflammation and fibrosis has been reported but never systematically evaluated.Patients with TAK were prospectively recruited from the National Institutes of Health (NIH) and the Vasculitis Clinical Research Consortium (VCRC). Based on clinical presentation at diagnosis, patients were divided into five categories: (1) constitutional symptoms alone, (2) carotidynia, (3) other vascular-associated symptoms, (4) major ischemic event, or (5) asymptomatic. Associated clinical characteristics were evaluated in each category. Preceding symptoms were also assessed to determine the presence of a triphasic disease pattern.A total of 275 patients with TAK were included (VCRC=208; NIH=67). Similar heterogeneity of clinical presentation was identified in each cohort: constitutional symptoms (8%), carotidynia (13-15%), other vascular symptoms (43-47%), major ischemic event (28-30%), and asymptomatic (2-6%). An increased relative proportion of males was seen in patients who presented with constitutional symptoms or were asymptomatic at diagnosis (p0.01). Patients who presented with constitutional symptoms and major ischemic events were youngest at diagnosis. Patients in the asymptomatic group were oldest at diagnosis and often were not treated (p0.01). Relapse was most frequent in patients who presented with carotidynia (p0.01). A minority of patients (19%) who presented with a major ischemic event reported a triphasic pattern of disease.There are diverse clinical presentations at diagnosis in TAK. Patients do not necessarily progress sequentially through phases of disease.

Glucocorticoids (GCs) are the gold standard for treatment of giant cell arteritis (GCA); however, there is a need for studies on GC-sparing agents, given that up to 85% of patients receiving GC only develop adverse events. Previous randomised controlled trials (RCTs) have applied different primary endpoints, limiting the comparison of treatment effects in meta-analyses and creating an undesired heterogeneity of outcomes. The harmonisation of response assessment is therefore an important unmet need in GCA research. In this viewpoint article, we discuss the challenges and opportunities with the development of new, internationally accepted response criteria. A change of disease activity is a fundamental component of response; however, it is debatable whether the ability to taper GC and/or the maintenance of a disease state for a specific time period, as applied in recent RCTs, should be part of response assessment. The role of imaging and novel laboratory biomarkers as possible objective markers of disease activity needs further investigation but might be a possibility when drugs directly or indirectly influence the levels of traditional acute-phase reactants such as erythrocyte sedimentation rate and C reactive protein. Futures response criteria might be constructed as a multidomain set, but the questions about which domains will be included and what their relative weights will be still need to be answered.

BACKGROUND Little is known about the autoreactive B cells in antineutrophil cytoplasmic antibody–associated (ANCA-associated) vasculitis (AAV). We aimed to investigate tolerance checkpoints of circulating antigen-specific proteinase 3–reactive (PR3+) B cells. METHODS Multicolor flow cytometry in combination with bioinformatics and functional in vitro studies were performed on baseline samples of PBMCs from 154 well-characterized participants of the RAVE trial (NCT00104299) with severely active PR3-AAV and myeloperoxidase-AAV (MPO-AAV) and 27 healthy controls (HCs). Clinical data and outcomes from the trial were correlated with PR3+ B cells (total and subsets). RESULTS The frequency of PR3+ B cells among circulating B cells was higher in participants with PR3-AAV (4.77% median [IQR, 3.98%–6.01%]) than in participants with MPO-AAV (3.16% median [IQR, 2.51%–5.22%]) and participants with AAV compared with HCs (1.67% median [IQR, 1.27%–2.16%], P < 0.001 for all comparisons), implying a defective central tolerance checkpoint in patients with AAV. Only PBMCs from participants with PR3-AAV contained PR3+ B cells capable of secreting PR3-ANCA IgG in vitro, proving they were functionally distinct from those of participants with MPO-AAV and HCs. Unsupervised clustering identified subtle subsets of atypical autoreactive PR3+ memory B cells accumulating through the maturation process in patients with PR3-AAV. PR3+ B cells were enriched in the memory B cell compartment of participants with PR3-AAV and were associated with higher serum CXCL13 levels, suggesting an increased germinal center activity. PR3+ B cells correlated with systemic inflammation (C-reactive protein and erythrocyte sedimentation rate, P < 0.05) and complete remission (P < 0.001). CONCLUSION This study suggests the presence of defective central antigen-independent and peripheral antigen-dependent checkpoints in patients with PR3-AAV, elucidating the selection process of autoreactive B cells. Trial registration ClinicalTrials.gov NCT00104299. Funding The Vasculitis Foundation, the National Institute of Allergy and Infectious Diseases of the NIH, and the Mayo Foundation for Education and Research.

Objective: ANCA-associated vasculitis (AAV) is characterized by fluctuating levels of disease activity, but no formal criteria exist to measure response to treatment. This Delphi exercise aimed to reach consensus about which measures are considered by patients and physicians to be most important when assessing response to treatment in clinical trials of AAV. Methods: An international 3-round online Delphi exercise was conducted. Survey participants included patients with AAV and physicians with expertise in AAV. Survey participants were asked to rate (on a scale of 1–9) the importance of each item when assessing response to treatment in AAV. Items scored 7–9 by ≥70% participants were considered highly important. Results: 89 patients and 176 physicians completed three rounds of the Delphi exercise. The most highly rated items of response involved disease activity [extent of organ involvement, physician global assessment], mortality [survival], and patient-reported outcomes [patient global assessment and health-related quality of life measures]. Achievement of specific BVAS scores were highly rated only by physicians. Items highly rated only by patients included laboratory measures [changes on urinalysis and acute phase reactants], pain, and fatigue. Additional items related to damage and adverse events were highly rated by both groups. Conclusion: There is consensus between patients and physicians on many items considered important to measure when assessing response to treatment in AAV. There are some items considered important by only patients or only physicians. These data will inform the next steps in the development criteria of response to treatment in AAV.

To provide evidence-based recommendations and expert guidance for the management of Kawasaki disease (KD), focusing on clinical scenarios more commonly addressed by rheumatologists.Sixteen clinical questions regarding diagnostic testing, treatment, and management of KD were developed in the Patient/Population, Intervention, Comparison, and Outcomes (PICO) question format. Systematic literature reviews were conducted for each PICO question. We used the Grading of Recommendations, Assessment, Development and Evaluation method to assess the quality of evidence and formulate recommendations. Each recommendation required consensus from at least 70% of the Voting Panel.We present 1 good practice statement, 11 recommendations, and 1 ungraded position statement to guide the management of KD and clinical scenarios of suspected KD. These recommendations for KD are focused on situations in which input from rheumatologists may be requested by other managing specialists, such as in cases of treatment-refractory, severe, or complicated KD. The good practice statement affirms that all patients with KD should receive initial treatment with intravenous immunoglobulin (IVIG). In addition, we developed 7 strong and 4 conditional recommendations for the management of KD or suspected KD. Strong recommendations include prompt treatment of incomplete KD, treatment with aspirin, and obtaining an echocardiogram in the setting of unexplained macrophage activation syndrome or shock. Conditional recommendations include use of IVIG with other adjuvant agents for patients with KD and high-risk features of IVIG resistance and/or coronary artery aneurysms. These recommendations endorse minimizing risk to the patient by using established therapy promptly at disease onset and identifying situations in which adjunctive therapy may be warranted.These recommendations provide guidance regarding diagnostic strategies, use of pharmacologic agents, and use of echocardiography in patients with suspected or confirmed KD.

Objective Improved biomarkers of current disease activity and prediction of relapse are needed in antineutrophil cytoplasmic antibody-associated vasculitis (AAV). For clinical relevance, biomarkers must perform well longitudinally in patients on treatment and in patients with nonsevere flares. Methods Twenty-two proteins were measured in 347 serum samples from 74 patients with AAV enrolled in a clinical trial. Samples were collected at Month 6 after remission induction, then every 3 months until Month 18, or at the time of flare. Associations of protein concentrations with concurrent disease activity and with future flare were analyzed using mixed-effects models, Cox proportional hazards models, and conditional logistic regression. Results Forty-two patients had flares during the 12-month follow-up period, and 32 remained in remission. Twenty-two patients had severe flares. Six experimental markers (CXCL13, IL-6, IL-8, IL-15, IL-18BP, and matrix metalloproteinase-3 [MMP-3]) and ESR were associated with disease activity using all three methods (P < 0.05, with P < 0.01 in at least one method). A rise in IL-8, IL-15, or IL-18BP was associated temporally with flare. Combining C-reactive protein (CRP), IL-18BP, neutrophil gelatinase-associated lipocalin (NGAL), and sIL-2R alpha improved association with active AAV. CXCL13 and MMP-3 were increased during treatment with prednisone, independent of disease activity. Marker concentrations during remission were not predictive of future flare. Conclusion Serum biomarkers of inflammation and tissue damage and repair have been previously shown to be strongly associated with severe active AAV were less strongly associated with active AAV in a longitudinal study that included mild flares and varying treatment. Markers rising contemporaneously with flare or with an improved association in combination merit further study.

We appreciate the insights and concerns shared by Dr. Jain et al. regarding the use of rituximab (RTX) and cyclophosphamide (CYC) for the treatment of granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA), as outlined in the American College of Rheumatology/Vasculitis Foundation (ACR/VF) guideline for the treatment of ANCA-associated vasculitis (AAV) [1]. These concerns are timely given the ongoing COVID-19 pandemic.

Objectives To develop and replicate, using data-driven methods, a novel classification system in Takayasu’s arteritis based on distribution of arterial lesions. Methods Patients were included from four international cohorts at major academic centres: India (Christian Medical College Vellore); North America (National Institutes of Health, Vasculitis Clinical Research Consortium and Cleveland Clinic Foundation). All patients underwent whole-body angiography of the aorta and branch vessels, with categorization of arterial damage (stenosis, occlusion or aneurysm) in 13 territories. K-means cluster analysis was performed to identify subgroups of patients based on pattern of angiographic involvement. Cluster groups were identified in the Indian cohort and independently replicated in the North American cohorts. Results A total of 806 patients with Takayasu’s arteritis from India (n = 581) and North America (n = 225) were included. Three distinct clusters defined by arterial damage were identified in the Indian cohort and replicated in each of the North American cohorts. Patients in cluster one had significantly more disease in the abdominal aorta, renal and mesenteric arteries (P < 0.01). Patients in cluster two had significantly more bilateral disease in the carotid and subclavian arteries (P < 0.01). Compared with clusters one and two, patients in cluster three had asymmetric disease with fewer involved territories (P < 0.01). Demographics, clinical symptoms and clinical outcomes differed by cluster. Conclusion This large study in Takayasu’s arteritis identified and replicated three novel subsets of patients based on patterns of arterial damage. Angiographic-based disease classification requires validation by demonstrating potential aetiological or prognostic implications.

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

Objective.We evaluated potential circulating biomarkers of disease activity in giant cell arteritis (GCA), Takayasu arteritis (TA), polyarteritis nodosa (PAN), and eosinophilic granulomatosis with polyangiitis (EGPA).Methods.A panel of 22 serum proteins was tested in patients enrolled in the Vasculitis Clinical Research Consortium Longitudinal Studies of GCA, TA, PAN, or EGPA. Mixed models were used for most analyses. A J48 classification tree method was used to find the most relevant markers to differentiate between active and inactive GCA.Results.Tests were done on 418 samples from 152 patients (60 GCA, 29 TA, 26 PAN, 37 EGPA), during both active vasculitis and remission. In GCA, these showed significant (p < 0.05) differences between disease states: B cell–attracting chemokine 1 (BCA)-1/CXC motif ligand 13 (CXCL13), erythrocyte sedimentation rate (ESR), interferon-γ—induced protein 10/CXC motif chemokine 10, soluble interleukin 2 receptor α (sIL-2Rα), and tissue inhibitor of metalloproteinase-1 (TIMP-1). In EGPA, these showed significant increases during active disease: granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage—CSF, interleukin (IL)-6, IL-15, and sIL-2Rα. BCA-1/CXCL13 also showed such increases, but only after adjustment for treatment. In PAN, ESR and matrix metalloprotease (MMP)-3 showed significant differences between disease states. Differences in biomarker levels between diseases were significant for 11 markers and were more striking (all p < 0.01) than differences related to disease activity. A combination of lower values of TIMP-1, IL-6, interferon-γ, and MMP-3 correctly classified 87% of samples with inactive GCA.Conclusion.We identified novel biomarkers of disease activity in GCA and EGPA. Differences of biomarker levels between diseases, independent of disease activity, were more apparent than differences related to disease activity. Further studies are needed to determine whether these serum proteins have potential for clinical use in distinguishing active disease from remission or in predicting longer-term outcomes.

Objectives To evaluate large-vessel (LV) abnormalities on serial imaging in patients with giant cell arteritis (GCA) and discern predictors of new lesions. Methods Clinical and imaging data from patients with GCA (including subjects diagnosed by LV imaging) enrolled in a prospective, multicenter, longitudinal study and/or a randomized clinical trial were included. New arterial lesions were defined as a lesion in a previously unaffected artery. Results The study included 187 patients with GCA, 146 (78%) female, mean (±SD) age at diagnosis 68.5 ± 8.5 years; 39% diagnosed by LV imaging. At least one arterial lesion was present in 123 (66%) on the first study. The most frequently affected arteries were subclavian (42%), axillary (32%), and thoracic aorta (20%). In 106 patients (57%) with serial imaging, new arterial lesions were noted in 41 patients (39%), all of whom had a baseline abnormality, over a mean (±SD) follow-up of 4.39 (2.22) years. New abnormalities were observed in 33% patients by year 2; clinical features of active disease were present at only 50% of these cases. There were no differences in age, sex, temporal artery biopsy positivity, or disease activity in patients with or without new lesions. Conclusions In this cohort of patients with GCA, LV abnormalities on first imaging were common. Development of new arterial lesions occurred in patients with arterial abnormalities at first imaging, often in the absence of symptoms of active disease. Arterial imaging should be considered in all patients with GCA at diagnosis and serial imaging at least in patients with baseline abnormalities.

Objective The Outcome Measures in Rheumatology (OMERACT) Vasculitis Working Group aims to develop composite response criteria for ANCA-Associated Vasculitis (AAV). Methods The project follows the OMERACT approach for composite measures: (i) choose relevant domains; (ii) define high-quality instruments; (iii) decide on a scoring system approach; (iv) put through the OMERACT Filter 2.1 for validation. Results A systematic literature review of outcome measures used in clinical trials in AAV and an international Delphi exercise among patients with AAV and clinician-investigators with expertise in AAV have been completed to inform the candidate domains/instruments for the composite response criteria, which are the first two steps in the OMERACT approach for developing composite measures. Results of the systematic literature review and Delphi were presented at the OMERACT 2020 virtual workshop, and feedback was received on the next steps of the project, including the development of a scoring system approach. Conclusion The ultimate goal of this project is to develop validated composite response criteria for use in clinical trials of AAV.

OBJECTIVE. Only a few small case series, case reports, and one small clinical trial suggested some benefit of leflunomide (LEF) in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis and other vasculitides. We analysed the clinical efficacy and tolerability of LEF in a large cohort of patients with various vasculitides. METHODS. This was a retrospective analysis of patients who received LEF for treatment of their vasculitis enrolled in the Vasculitis Clinical Research Consortium (VCRC) Longitudinal Study and in 3 additional centres from the Canadian vasculitis research network (CanVasc). RESULTS. Data for 93 patients were analysed: 45 had granulomatosis with polyangiitis (GPA), 8 microscopic polyangiitis (MPA), 12 eosinophilic granulomatosis with polyangiitis (EGPA), 14 giant-cell arteritis (GCA), 9 Takayasu’s arteritis (TAK), and 5 polyarteritis nodosa (PAN). The main reason for initiation of LEF was active disease (89%). LEF was efficacious for remission induction or maintenance at 6 months for 62 (67%) patients (64% with GCA, 89% with TAK, 80% with PAN, 69% with GPA, 75% with MPA, 33% with EGPA); 20% discontinued LEF before achieving remission because of persistent disease activity. Overall, 22 adverse events (gastrointestinal symptoms being the most common) led to drug discontinuation in 18 (19%) patients, of which 12 stopped LEF before month 6, before showing any benefit in 8/12 of these patients. CONCLUSION. Leflunomide can be an effective therapeutic option for various vasculitides, especially for non-severe refractory or relapsing ANCA-associated vasculitis or large-vessel vasculitis. No new safety signals for LEF were identified in this population.

Objective To provide evidence-based recommendations and expert guidance for the management of systemic polyarteritis nodosa (PAN). Methods Twenty-one clinical questions regarding diagnostic testing, treatment, and management were developed in the population, intervention, comparator, and outcome (PICO) format for systemic, non-hepatitis B-related PAN. Systematic literature reviews were conducted for each PICO question. The Grading of Recommendations Assessment, Development and Evaluation methodology was used to assess the quality of evidence and formulate recommendations. Each recommendation required ≥70% consensus among the Voting Panel. Results We present 16 recommendations and 1 ungraded position statement for PAN. Most recommendations were graded as conditional due to the paucity of evidence. These recommendations support early treatment of severe PAN with cyclophosphamide and glucocorticoids, limiting toxicity through minimizing long-term exposure to both treatments, and the use of imaging and tissue biopsy for disease diagnosis. These recommendations endorse minimizing risk to the patient by using established therapy at disease onset and identify new areas where adjunctive therapy may be warranted. Conclusion These recommendations provide guidance regarding diagnostic strategies, use of pharmacologic agents, and imaging for patients with PAN.

ObjectivesEvaluation of rituximab and glucocorticoids as therapy to induce remission after relapse in ANCA-associated vasculitis (AAV) in a prospective observational cohort of patients enrolled into the induction phase of the RITAZAREM trial.MethodsPatients relapsing with granulomatosis with polyangiitis or microscopic polyangiitis were prospectively enrolled and received remission-induction therapy with rituximab (4×375 mg/m2) and a higher or lower dose glucocorticoid regimen, depending on physician choice: reducing from either 1 mg/kg/day or 0.5 mg/kg/day to 10 mg/day by 4 months. Patients in this cohort achieving remission were subsequently randomised to receive one of two regimens to prevent relapse.Results188 patients were studied: 95/188 (51%) men, median age 59 years (range 19–89), prior disease duration 5.0 years (range 0.4–34.5). 149/188 (79%) had previously received cyclophosphamide and 67/188 (36%) rituximab. 119/188 (63%) of relapses had at least one major disease activity item, and 54/188 (29%) received the higher dose glucocorticoid regimen. 171/188 (90%) patients achieved remission by 4 months. Only six patients (3.2% of the study population) did not achieve disease control at month 4. Four patients died in the induction phase due to pneumonia (2), cerebrovascular accident (1), and active vasculitis (1). 41 severe adverse events occurred in 27 patients, including 13 severe infections.ConclusionsThis large prospective cohort of patients with relapsing AAV treated with rituximab in conjunction with glucocorticoids demonstrated a high level of efficacy for the reinduction of remission in patients with AAV who have relapsed, with a similar safety profile to previous studies.

The immunologic mechanisms promoting eosinophilic granulomatosis with polyangiitis (EGPA) are unclear. To characterize the mechanisms underlying pulmonary EGPA, we examined and compared EGPA paraffin-embedded lung biopsies with normal lung biopsies, using immunostaining, RNA sequencing, and RT-PCR. The results revealed novel type 2 as well as immuneregulatory features. These features included basophils and increased mast cell contents; increased immunostaining for tumor necrosis factor ligand superfamily member 14; sparse mast cell degranulation; numerous forkhead box protein P3 (FoxP3)+ regulatory T cells and IgG4 plasma cells; and abundant arachidonate 15-lipoxygenase and 25-hydroxyvitamin D-1 α hydroxylase, mitochondrial. Significantly decreased 15-hydroxyprostaglandin dehydrogenase [NAD((+))], which degrades eicosanoids, was observed in EGPA samples. In addition, there was significantly increased mRNA for chemokine (C-C motif) ligands 18 and 13 and major collagen genes, IgG4-rich immune complexes coating alveolar macrophages, and increased immunostaining for phosphorylated mothers against decapentaplegic homolog 2/SMAD2, suggesting transforming growth factor-β activation. These findings suggest a novel self-promoting mechanism of activation of alveolar macrophages by arachidonate 15-lipoxygenase–derived eicosanoids to express chemokines that recruit a combined type 2/immunoregulatory immune response, which produces these eicosanoids. These results suggest that the pulmonary EGPA immune response resembles the immune response to a tissue-invasive parasite infection.

BACKGROUND: A comprehensive review of outcome measures used in randomized controlled trials (RCTs) of ANCA-associated vasculitis (AAV) could advance trial conductance for this disease.METHODS: A systematic literature review of outcome measures (as specified in methods section as primary and/or secondary outcomes) in RCTs of AAV was conducted. Medline, Cochrane CENTRAL, and ClinicalTrials.gov were searched from inception until April 30, 2019 for RCTs enrolling patients with granulomatosis with polyangiitis and/or microscopic polyangiitis. Outcome measures were organized according to domains (e.g. disease activity) and instruments [e.g. Birmingham Vasculitis Activity Score (BVAS)].RESULTS: Out of 1101 identified records, 68 RCTs were eligible. Disease activity was an outcome domain collected in 67 (98%) of the RCTs. The BVAS was the most widely used instrument for disease assessment but definitions for remissions and relapse varied for the purpose of primary endpoint definitions. Damage, most often assessed by the Vasculitis Damage Index, was an outcome in 30 (44%) of the RCTs. Mortality was specified as an outcome in 26 (38%) studies. The following outcome domains were assessed: patient-reported outcomes (PROs) in 28 (41%), drug exposure/safety in 58 (85%), and biomarkers [acute phase reactants, ANCA levels] in 24 (35%). Timing for outcome assessment differed substantially, with 3, 6, or 12 months being the most frequent time points.CONCLUSION: Outcome measures used in trials in AAV commonly included vasculitis-specific tools for disease assessment, but with heterogeneity in endpoint-definitions and timing of assessments. Other core outcomes in AAV, including PROs, and damage measures, are often omitted in AAV trials.

Objectives. To study the determinants of the pharmacokinetics (PK) of rituximab (RTX) in patients with ANCA-associated vasculitis (AAV) and its association with clinical outcomes.Methods. This study included data from 89 patients from the RTX in AAV trial who received the full dose of RTX (four weekly infusions of 375 mg/m(2)). RTX was quantified at weeks 2, 4, 8, 16 and 24, and summarized by computing the trapezoidal area under the curve. We explored potential determinants of the PK-RTX, and analysed its association with clinical outcomes: achievement of remission at 6 months, duration of B-cell depletion and time to relapse in patients who achieved complete remission.Results. RTX serum levels were significantly lower in males and in newly diagnosed patients, and negatively correlated with body surface area, baseline B-cell count and degree of disease activity. In multivariate analyses, the main determinants of PK-RTX were sex and new diagnosis. Patients reaching complete remission at month 6 had similar RTX levels compared with patients who did not reach complete remission. Patients with higher RTX levels generally experienced longer B-cell depletion than patients with lower levels, but RTX levels at the different time points and area under the curve were not associated with time to relapse.Conclusion. Despite the body-surface-area-based dosing protocol, PK-RTX is highly variable among patients with AAV, its main determinants being sex and newly diagnosed disease. We did not observe any relevant association between PK-RTX and clinical outcomes. The monitoring of serum RTX levels does not seem clinically useful in AAV.

Objective To identify risk alleles relevant to the causal and biologic mechanisms of antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis (AAV). Methods A genome-wide association study and subsequent replication study were conducted in a total cohort of 1,986 cases of AAV (patients with granulomatosis with polyangiitis [Wegener's] [GPA] or microscopic polyangiitis [MPA]) and 4,723 healthy controls. Meta-analysis of these data sets and functional annotation of identified risk loci were performed, and candidate disease variants with unknown functional effects were investigated for their impact on gene expression and/or protein function. Results Among the genome-wide significant associations identified, the largest effect on risk of AAV came from the single-nucleotide polymorphism variants rs141530233 and rs1042169 at the HLA–DPB1 locus (odds ratio [OR] 2.99 and OR 2.82, respectively) which, together with a third variant, rs386699872, constitute a triallelic risk haplotype associated with reduced expression of the HLA–DPB1 gene and HLA–DP protein in B cells and monocytes and with increased frequency of complementary proteinase 3 (PR3)–reactive T cells relative to that in carriers of the protective haplotype. Significant associations were also observed at the SERPINA1 and PTPN22 loci, the peak signals arising from functionally relevant missense variants, and at PRTN3, in which the top-scoring variant correlated with increased PRTN3 expression in neutrophils. Effects of individual loci on AAV risk differed between patients with GPA and those with MPA or between patients with PR3-ANCAs and those with myeloperoxidase-ANCAs, but the collective population attributable fraction for these variants was substantive, at 77%. Conclusion This study reveals the association of susceptibility to GPA and MPA with functional gene variants that explain much of the genetic etiology of AAV, could influence and possibly be predictors of the clinical presentation, and appear to alter immune cell proteins and responses likely to be key factors in the pathogenesis of AAV.

Summary Anti-neutrophil cytoplasmic antibodies (ANCA) appear to play an important role in the pathogenesis of ANCA-associated vasculitis (AAV). However, ANCA alone are not sufficient to generate disease, and some evidence suggests that infectious triggers may serve as inciting events for AAV disease activity. Antibodies of the immunoglobulin (Ig)M isotype often serve as markers of recent infection, and IgM ANCA have been identified previously in patients with AAV, although the frequency and clinical relevance of IgM ANCA is not well established. We sought to characterize IgM ANCA more clearly by creating a novel enzyme-linked immunosorbent assay (ELISA) for IgM antibodies to proteinase 3 [IgM proteinase 3 (PR3)–ANCA], which we applied to two large, clinically well-characterized trial cohorts of patients with granulomatosis with polyangiitis and microscopic polyangiitis. In the first cohort, IgM PR3–ANCA occurred with a frequency of 15·0%, and were associated with a higher degree of disease severity and a trend towards a higher rate of alveolar haemorrhage (29·6 versus 15·7%, P = 0·10). Analysis of follow-up samples in this cohort showed that the presence of IgM PR3–ANCA was transient, but could recur. In the second cohort, IgM PR3–ANCA occurred with a frequency of 41·1%, and were also associated with a higher degree of disease severity. A higher rate of alveolar haemorrhage was observed among those with IgM PR3–ANCA (45·3 versus 15·8%; P

Background: Immunopathologic features predict renal function at baseline and follow-up in antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (GN). The interstitial infiltrate consists predominantly of T lymphocytes, but their pathophysiologic significance is unclear, especially in light of the success of B-cell-directed therapy. Methods: Renal biopsies from 33 patients treated with cyclophosphamide (CYC; n = 17) or rituximab (RTX; n = 16) in the RTX in ANCA-associated vasculitis (RAVE) trial were classified according to the new ANCA GN classification. T- and B-cell infiltration in the interstitium was assessed by immunostaining for CD3 and CD20. Correlations of clinical and histologic parameters with renal function at set time points were examined. Results: The mean (SD) baseline estimated glomerular filtration rate was 36 (20) mL/min/1.73 m2. ANCA GN class distribution was 46% focal, 33% mixed, 12% sclerotic and 9% crescentic. The interstitial infiltrate consisted of >50% CD3 positive cells in 69% of biopsies, but >50% CD20 positive cells only in 8% of biopsies. In a multiple linear regression model, only baseline glomerular filtration rate (GFR) correlated with GFR at 6, 12, and 18 months. Interstitial B- and T-cell infiltrates had no significant impact on long-term prognosis, independent of the treatment limb. A differential effect was noted only at 6 months, where a dense CD3 positive infiltrate predicted lower GFR in the RTX group and a CD20 positive infiltrate predicted higher GFR in the CYC group. Conclusions: In ANCA-associated GN, the interstitial infiltrate contains mainly T lymphocytes. However, it is neither reflecting baseline renal function nor predictive of response to treatment, regardless of the immunosuppression regimen employed.

Objective S100A8/A9 (calprotectin) has shown promise as a biomarker for predicting relapse in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). This study was undertaken to investigate serum S100A8/A9 level as a biomarker for predicting future relapse in a large cohort of patients with severe AAV.Methods Serum levels of S100A8/A9 were measured at baseline and months 1, 2, and 6 following treatment initiation in 144 patients in the Rituximab in ANCA-Associated Vasculitis trial (cyclophosphamide/azathioprine versus rituximab [RTX] for induction of remission) in whom complete remission was attained.Results Patients were divided into 4 groups: proteinase 3 (PR3)-ANCA with relapse (n=37), PR3-ANCA without relapse (n=56), myeloperoxidase (MPO)-ANCA with relapse (n=6), and MPO-ANCA without relapse (n=45). Serum S100A8/A9 level decreased in all groups during the first 6 months of treatment. The percentage reduction from baseline to month 2 was significantly different between patients who experienced a relapse and those who did not in the PR3-ANCA group (P=0.046). A significantly higher risk of relapse was associated with an increase in S100A8/A9 level between baseline and month 2 (P=0.0043) and baseline and month 6 (P=0.0029). Subgroup analysis demonstrated that patients treated with RTX who had increased levels of S100A8/A9 were at greatest risk of future relapse (P=0.028).Conclusion An increase in serum S100A8/A9 level by month 2 or 6 compared to baseline identifies a subgroup of PR3-ANCA patients treated with RTX who are at higher risk of relapse by 18 months. Since RTX is increasingly used for remission induction in PR3-ANCA-positive patients experiencing a relapse, S100A8/A9 level may assist in identifying those patients requiring more intensive or prolonged treatment.

Objective: To investigate serum IL-6 (sIL-6) levels during active disease, complete remission (CR), and relapse in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), and to explore the association of changes in sIL-6 with clinical outcomes.Methods: sIL-6 levels were measured at baseline and longitudinally over 18 months, in 78 patients with AAV enrolled in a randomized controlled trial comparing treatment with either rituximab (RTX) or cyclophosphamide (CYC)/azathioprine (AZA). Outcome variables included baseline clinical features, ANCA specificity, disease activity (active disease versus CR), time to relapse events, B cell repopulation, and ANCA titer increases.Results: At baseline, sIL6 levels were detectable in 81% of patients; 73% (n = 57) of subjects were proteinase 3 (PR3)-ANCA positive, sIL-6 levels were higher in subjects with PR3-ANCAs and positively correlated with their levels (r(s) = 0.36,p 0.05).Conclusion: At baseline, sIL-6 concentrations correlate with PR3-ANCA titers and are associated with specific clinical manifestations of AAV. Baseline sIL6 concentrations do not predict CR at 6 months, but the increase in sIL-6 concentrations during CR is associated with subsequent severe relapse among RTX-treated patients. Further investigation into the mechanistic role of IL6 in AAV might lead to identifying this pathway as a potential therapeutic target in this disease.

BACKGROUND: In a recent phase III trial (NCT02020889) 53% of mepolizumab-treated versus 19% of placebo-treated patients with eosinophilic granulomatosis with polyangiitis (EGPA) achieved protocol-defined remission. OBJECTIVE: We sought to investigate post hoc the clinical benefit of mepolizumab in patients with EGPA using a comprehensive definition of benefit encompassing remission, oral glucocorticoid (OGC) dose reduction, and EGPA relapses. METHODS: The randomized, placebo-controlled, double-blind, parallel-group trial recruited patients with relapsing/refractory EGPA receiving stable OGCs (prednisolone/prednisone, ≥7.5-50 mg/d) for 4 or more weeks. Patients received 300 mg of subcutaneous mepolizumab or placebo every 4 weeks for 52 weeks. Clinical benefit was defined post hoc as follows: remission at any time (2 definitions used), 50% or greater OGC dose reduction during weeks 48 to 52, or no EGPA relapses. The 2 remission definitions were Birmingham Vasculitis Activity Score of 0 plus OGC dose of 4 mg/d or less (remission 1/clinical benefit 1) or 7.5 mg/d or less (remission 2/clinical benefit 2). Clinical benefit was assessed in all patients and among subgroups with a baseline blood eosinophil count of less than 150 cells/μL, baseline OGC dosage of greater than 20 mg/d, or weight of greater than 85 kg. RESULTS: With mepolizumab versus placebo, 78% versus 32% of patients experienced clinical benefit 1, and 87% versus 53% of patients experienced clinical benefit 2 (both P < .001). Significantly more patients experienced clinical benefit 1 with mepolizumab versus placebo in the blood eosinophil count less than 150 cells/μL subgroup (72% vs 43%, P = .033) and weight greater than 85 kg subgroup (68% vs 23%, P = .005); in the OGC greater than 20 mg/d subgroup, results were not significant but favored mepolizumab (60% vs 36%, P = .395). CONCLUSION: When a comprehensive definition of clinical benefit was applied to data from a randomized controlled trial, 78% to 87% of patients with EGPA experienced benefit with mepolizumab.