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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.

Introduction/aims Intracellular congophilic inclusions within muscle fibers, although nonspecific, are one of the pathological hallmarks of sporadic inclusion body myositis (sIBM). Extracellular amyloid deposits in muscle, on the other hand, are the canonical findings of amyloid myopathies, which occur with or without systemic amyloidosis. Methods We reviewed the muscle biopsy database (1998-2020) to identify sIBM patients with extracellular amyloid deposits. Clinical and laboratory data were reviewed. Results We identified five sIBM patients (three clinicopathologically defined and two clinically defined) with extracellular amyloid deposits in muscle. Mean age at diagnosis was 74.8 y (range, 68-84 y). All patients had a typical sIBM pattern of weakness without associated sensory or autonomic symptoms. None had electrophysiological evidence of peripheral neuropathy. Only one patient had a monoclonal gammopathy (immunoglobulin M-lambda, IgM-λ) with normal bone marrow biopsy. This patient with monoclonal gammopathy and three other patients underwent abdominal fat pad aspirate and were negative for amyloid. Cardiac evaluation was unrevealing in the four patients tested. Three patients without monoclonal gammopathy had normal transthyretin gene sequencing and inconclusive mass spectrometry-based analysis. The patient with monoclonal gammopathy died of pneumosepsis 5 y after diagnosis and autopsy revealed multi-organ transthyretin amyloidosis. Discussion Detection of extracellular amyloid deposition in muscle should trigger an aggressive search for systemic amyloidosis independently from other associated myopathological abnormalities. Amyloid subtyping is crucial for early therapy and mortality prevention. An isolated monoclonal gammopathy should not halt a search for non-hematological causes of systemic amyloidosis.

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.

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.

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.

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.

ObjectivesEvaluate risk of major adverse cardiovascular events (MACE) with tofacitinib versus tumour necrosis factor inhibitors (TNFi) in patients with rheumatoid arthritis (RA) with or without a history of atherosclerotic cardiovascular disease (ASCVD) in ORAL Surveillance.MethodsPatients with RA aged ≥50 years with ≥1 additional CV risk factor received tofacitinib 5 mg or 10 mg two times per day or TNFi. Hazard rations (HRs) were evaluated for the overall population and by history of ASCVD (exploratory analysis).ResultsRisk of MACE, myocardial infarction and sudden cardiac death were increased with tofacitinib versus TNFi in ORAL Surveillance. In patients with history of ASCVD (14.7%; 640/4362), MACE incidence was higher with tofacitinib 5 mg two times per day (8.3%; 17/204) and 10 mg two times per day (7.7%; 17/222) versus TNFi (4.2%; 9/214). HR (combined tofacitinib doses vs TNFi) was 1.98 (95% confidence interval (CI) 0.95 to 4.14; interaction p values: 0.196 (for HR)/0.059 (for incidence rate difference)). In patients without history of ASCVD, MACE HRs for tofacitinib 5 mg two times per day (2.4%; 30/1251) and 10 mg two times per day (2.8%; 34/1234) versus TNFi (2.3%; 28/1237) were, respectively, 1.03 (0.62 to 1.73) and 1.25 (0.76 to 2.07).ConclusionsThis post hoc analysis observed higher MACE risk with tofacitinib versus TNFi in patients with RA and history of ASCVD. Among patients without history of ASCVD, all with prevalent CV risk factors, MACE risk did not appear different with tofacitinib 5 mg two times per day versus TNFi. Due to the exploratory nature of this analysis and low statistical power, we cannot exclude differential MACE risk for tofacitinib 5 mg two times per day versus TNFi among patients without history of ASCVD, but any absolute risk excess is likely low.Trial registration numberNCT02092467.

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 To describe the differences in clinical characteristics and outcome between adult- and childhood-onset biopsy-proven IgA vasculitis (IgAV) in North America. Patients and Methods Patients with IgAV diagnosed from January 1, 1997, through December 31, 2016, were retrospectively identified. Data were abstracted from direct medical record review. Kaplan-Meier methods were used to estimate survival rates. Results A total of 243 patients with IgAV were included (227 [93.4%] white, 141 [58.0%] male); 174 patients were adults (≥21 years), and 69 were younger than 21 years. Compared with patients younger than 21 years, adults at baseline more frequently had ulcerative skin lesions (19 [10.9%] vs 1 [1.4%]; P=.02) and nephrotic-range proteinuria (21 of 96 [21.9%] vs 1 of 38 [2.6%]; P=.007) but less commonly had abdominal pain (59 [33.9%] vs 42 [60.9%]; P Conclusion IgA vasculitis in adults is associated with more severe skin/kidney involvement and poorer renal outcome. Among adults with IgAV, patients aged 51 years or older at diagnosis have significantly higher mortality (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.

Objective.To characterize the indication, outcomes, and adverse effects of rituximab (RTX) treatment in a large single-center cohort of patients with systemic rheumatoid vasculitis (RV).Methods.We retrospectively reviewed the medical charts of 17 patients treated with RTX for systemic RV from 2000 to 2017. Clinical characteristics, outcomes, and adverse effects were analyzed.Results.At RV diagnosis, mean age was 59 years, 59% were female, 94% were white, and 82% had positive rheumatoid factor. At the time of initiating RTX, median Birmingham Vasculitis Activity Score for rheumatoid arthritis was 4.0 (interquartile range 2.0–7.5). RV presented in the skin in 8 patients (47%), as mononeuritis multiplex in 2 (12%), inflammatory ocular disease in 2 (12%), and affected multiple organ systems in 5 (29%). RTX was used for induction therapy in 8 patients (47%), relapsing RV in 4 (24%), second-line therapy in 2 (12%), and salvage therapy or in combination with another agent in 3 (18%). At 3 months, 2 (13%) of 15 patients with available followup information achieved complete remission (CR), and 10 (67%) achieved partial response (PR). At 6 months, 6 patients (40%) achieved CR, 8 (53%) achieved PR, and one had no response. At 12 months, 8 of 13 patients with available records (62%) had CR and 5 patients (38%) had PR.Conclusion.Systemic RV is difficult to treat effectively. CR of RV was achieved in 62% and PR in 38% of patients within 12 months of RTX use. Further evidence is needed to inform treatment for patients with RV.

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 Cigarette smoking is associated with immune-mediated disorders. We explored the contribution of smoking to polymyositis (PM) and dermatomyositis (DM) phenotypes and attempted to determine whether cigarette smoking effects differ by race and genotype. Methods Associations of tobacco smoking with disease features, autoantibodies, HLA types, and race were evaluated using multiple logistic regressions in 465 patients. Results Caucasian ever-smokers (n = 140) were more likely to have PM (adjusted OR = 2.24, 95% CI: 1.41\x963.57), anti-synthetase (adjusted OR = 1.93, 95% CI: 1.12\x963.34) and anti-Jo-1 autoantibodies (adjusted OR = 1.94, 95% CI: 1.08\x963.46) and less likely to have anti-p155/140 autoantibodies (adjusted OR = 0.36, 95% CI: 0.14\x960.92). In Caucasians, ever-smokers had a greater interstitial lung disease (ILD) frequency than never-smokers, while in African-Americans this relationship was inverted, but neither trend reached statistical significance. Pack-years of cigarette smoking showed significant positive associations with PM (adjusted OR = 1.02, 95% CI: 1.002\x961.04) and ILD (adjusted OR = 1.02, 95% CI: 1.001\x961.03) and was inversely associated with anti-p155/140 autoantibodies (adjusted OR = 0.93, 95% CI: 0.87\x960.99) in Caucasians. Caucasian heavy smokers (=20 pack-years) were more likely to have PM (adjusted OR = 2.52, 95% CI: 1.25\x965.09), ILD (adjusted OR = 2.48, 95% CI: 1.23\x965.00) and anti-Jo-1 autoantibodies (adjusted OR = 2.65, 95% CI: 1.16\x966.08) than never-smokers. In Caucasians, compared to never-smokers without HLA-DRB1*03:01 allele, ever-smokers with HLA-DRB1*03:01 allele had the highest odds of PM, ILD, ASA, and anti-Jo-1 autoantibodies. Risks for those with only one of these two factors were intermediate. An inverse pattern was observed regarding anti-p155/140 autoantibodies. Conclusion Tobacco smoking was associated with clinical and autoantibody phenotypes in Caucasians. Our findings also suggest possible interactions among HLA-DRB1*03:01 and smoking on the risk of PM and ILD, as well as, anti-synthetase, anti-Jo-1, and anti-p155/140 autoantibodies in Caucasians.

Objectives: Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis of medium-sized visceral vessels. However, cutaneous arteritis (CA) and gastrointestinal (GI) vasculitis are forms of single organ vasculitis having indistinguishable histopathological findings from PAN. The aim of this study was to evaluate and compare the clinical characteristics, treatment, and outcomes of patients with systemic PAN, CA and GI vasculitis. Methods: Retrospective cohorts were assembled of patients with PAN, CA and GI vasculitis between 1980 and 2014. The demographics, clinical characteristics, treatment and outcomes of patients were abstracted from medical records. Results: We included 48 patients with PAN, 41 patients with CA, and 19 patients with GI vasculitis. One patient presenting as CA evolved to systemic PAN during the disease course. At diagnosis, 94% of patients with PAN, 93% of patients with CA and 67% of patients with GI vasculitis were treated with glucocorticoids. Additional immunosuppressive agents were used in 67% of PAN, 37% of GI vasculitis and 32% of CA. The five-year cumulative relapse rate was 45.2% in CA, and only 9.6% in PAN during follow-up of about 6 years.No deaths were observed in the CA group.Survival at 10-years was 66% in the PAN and 61% in GI vasculitis group. Conclusion: Systemic PAN, CA and GI vasculitis demonstrate different clinical courses and therefore may be different diseases rather than a spectrum of the same disease. Progression of CA to systemic PAN is very rare. Relapse risk is low during follow-up in PAN. Patients with CA have a higher relapse rate compared to those with systemic PAN, possibly due to lower use of immunosuppressive therapy in the former group. This article is protected by copyright. All rights reserved.

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

ObjectiveTo develop and validate new classification criteria for adult and juvenile idiopathic inflammatory myopathies (IIM) and their major subgroups.MethodsCandidate variables were assembled from published criteria and expert opinion using consensus methodology. Data were collected from 47 rheumatology, dermatology, neurology and paediatric clinics worldwide. Several statistical methods were used to derive the classification criteria.ResultsBased on data from 976 IIM patients (74% adults; 26% children) and 624 non-IIM patients with mimicking conditions (82% adults; 18% children), new criteria were derived. Each item is assigned a weighted score. The total score corresponds to a probability of having IIM. Subclassification is performed using a classification tree. A probability cut-off of 55%, corresponding to a score of 5.5 (6.7 with muscle biopsy) ‘probable IIM’, had best sensitivity/specificity (87%/82% without biopsies, 93%/88% with biopsies) and is recommended as a minimum to classify a patient as having IIM. A probability of ≥90%, corresponding to a score of ≥7.5 (≥8.7 with muscle biopsy), corresponds to ‘definite IIM’. A probability of ConclusionsThe European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria for IIM have been endorsed by international rheumatology, dermatology, neurology and paediatric groups. They employ easily accessible and operationally defined elements, and have been partially validated. They allow classification of ‘definite’, ‘probable’ and ‘possible’ IIM, in addition to the major subgroups of IIM, including juvenile IIM. They generally perform better than existing criteria.

Background: Leukocytoclastic vasculitis has been reported in patients with inflammatory bowel disease (IBD) but cases of IgA vasculitis (IgAV) in IBD are considered rare. Objectives: The purpose of this study was to describe the baseline characteristics and outcome of a series of patients with IBD and IgAV. Methods: Biopsy-proven IgAV-patients with prior history of IBD were identified retrospectively at Mayo Clinic, Rochester, MN. Data were abstracted from direct medical chart review. Each IBD-IgAV case was matched to two controls with IgAV but without IBD history based on age, sex and baseline renal function at time of IgAV onset. Results: A total of 9 patients were included in the study group (6 male, 3 female). Crohn’s disease (CD) and Ulcerative Colitis (UC) were present in 7 and 2 patients, respectively. The mean length of time between IBD diagnosis and onset of IgAV was 17.3±19.9 years. For patients on biologic treatment for IBD, the mean length of time between initiation of biologic and onset of IgAV was 3.3±3.8 years (range 0-12 years). Active IBD at IgAV-onset was present in 56% (5/9) of patients. Tumor necrosis factor inhibitors (TNFi) were the most frequent biologics used for IBD (8, 89%); infliximab was the most common (7, 78%). At IgAV-onset, only 5 patients were on treatment with TNFi; two subsequently discontinued, two switched to another TNFi (adalimumab), and one patient continued. At last follow-up, two of three patients that remained on TNFi had full resolution of IgAV despite ongoing TNFi use. Comparison of baseline characteristics between cases with IBD-IgAV and matched non-IBD IgAV controls is demonstrated in Table 1. No differences were seen in regards to development of end-stage renal disease, resolution of hematuria and/or proteinuria, time to complete IgAV response or first IgAV relapse. Conclusion: Baseline characteristics and outcomes of patients with IBD-IgAV are similar to those with IgAV without IBD. Development of IgAV is not limited to patients with clinically active IBD. Whether use of TNFi is related to the pathogenesis of IgAV in some patients with IBD remains unclear. Further research into the pathophysiologic connection between IBD and IgAV is needed. References [1] Saint Marcoux B, De Bandt M. Vasculitides induced by TNFalpha antagonists: a study in 39 patients in France. Joint, bone, spine : revue du rhumatisme. 2006;73(6):710-3. [2] Sy A, Khalidi N, Dehghan N, Barra L, Carette S, Cuthbertson D, et al. Vasculitis in patients with inflammatory bowel diseases: A study of 32 patients and systematic review of the literature. Seminars in arthritis and rheumatism. 2016;45(4):475-82. [3] Ko JS, Uberti G, Napekoski K, Patil DT, Billings SD. Cutaneous manifestations in inflammatory bowel disease: a single institutional study of non-neoplastic biopsies over 13 years. Journal of cutaneous pathology. 2016;43(11):946-55. [4] Ozen S, Pistorio A, Iusan SM, Bakkaloglu A, Herlin T, Brik R, et al. EULAR/PRINTO/PRES criteria for Henoch-Schonlein purpura, childhood polyarteritis nodosa, childhood Wegener granulomatosis and childhood Takayasu arteritis: Ankara 2008. Part II: Final classification criteria. Ann Rheum Dis. 2010;69(5):798-806. [5] Laresche C, Locatelli F, Biver-Dalle C, Nachury M, Heyd B, Koch S, et al. Severe Henoch-Schonlein purpura complicating infliximab therapy for ulcerative colitis. Cutis. 2017;99(1):E20-e2. Disclosure of Interests: None declared

OBJECTIVE To identify and validate, using computer-driven methods, patterns of arterial disease in Takayasu arteritis (TAK) and giant cell arteritis (GCA). METHODS Patients with TAK or GCA were studied from the Diagnostic and Classification Criteria for Vasculitis (DCVAS) cohort and a combined North American cohort. Case inclusion required evidence of large-vessel involvement, defined as stenosis, occlusion, or aneurysm by angiography/ultrasonography, or increased 18 F-fluorodeoxyglucose (FDG) uptake by positron emission tomography (PET) in at least 1 of 11 specified arterial territories. K-means cluster analysis identified groups of patients based on the pattern of arterial involvement. Cluster groups were identified in the DCVAS cohort and independently validated in the North American cohort. RESULTS A total of 1,068 patients were included (DCVAS cohort: TAK = 461, GCA = 217; North American cohort: TAK = 225, GCA = 165). Six distinct clusters of patients were identified in DCVAS and validated in the North American cohort. Patients with TAK were more likely to have disease in the abdominal vasculature, bilateral disease of the subclavian and carotid arteries, or focal disease limited to the left subclavian artery than GCA (P < 0.01). Patients with GCA were more likely to have diffuse disease, involvement of bilateral axillary/subclavian arteries, or minimal disease without a definable pattern than TAK (P < 0.01). Patients with TAK were more likely to have damage by angiography, and patients with GCA were more likely to have arterial FDG uptake by PET without associated vascular damage. CONCLUSION Arterial patterns of disease highlight both shared and divergent vascular patterns between TAK and GCA and should be incorporated into classification criteria for large-vessel vasculitis.

ObjectiveProteinase 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.MethodsThe recombinant PR3 variants, iPR3 which is clinically used to detect PR3-ANCAs and iHm5 which contains three point mutations in Epitope 1 and 5 generated for epitope mapping studies, immunoassays and serum samples from patients enrolled in ANCA-associated vasculitis (AAV) clinical trials were used to screen the differential PR3-ANCA binding. Selective binding was determined by inhibition experiments.ResultsRather than a reduced binding of PR3-ANCAs to iHm5, we found substantially increased binding of the majority of PR3-ANCAs to iHm5 compared with iPR3. A monoclonal ANCA (moANCA518) from a patient with GPA was found to selectively bind to iHm5 within the mutation-free Epitope 3 and distant from the point mutations of iHm5 contained in Epitope 1 and 5. Binding of iPR3 to monoclonal antibody MCPR3-2 also induced recognition by moANCA518.ConclusionThe 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 it is 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.

Objectives To describe tracheobronchial disease in patients with granulomatosis with polyangiitis (GPA) and evaluate the utility of dynamic expiratory CT to detect large-airway disease. Methods Demographic and clinical features associated with the presence of subglottic stenosis (SGS) or endobronchial involvement were assessed in a multicentre, observational cohort of patients with GPA. A subset of patients with GPA from a single-centre cohort underwent dynamic chest CT to evaluate the airways. Results Among 962 patients with GPA, SGS and endobronchial disease were identified in 95 (10%) and 59 (6%) patients, respectively. Patients with SGS were more likely to be female (72% vs 53%, P < 0.01), younger at time of diagnosis (36 vs 49 years, P < 0.01), and have saddle-nose deformities (28% vs 10%, P < 0.01), but were less likely to have renal involvement (39% vs 62%, P < 0.01). Patients with endobronchial disease were more likely to be PR3-ANCA positive (85% vs 66%, P < 0.01), with more ENT involvement (97% vs 77%, P < 0.01) and less renal involvement (42% vs 62%, P < 0.01). Disease activity in patients with large-airway disease was commonly isolated to the subglottis/upper airway (57%) or bronchi (32%). Seven of 23 patients screened by dynamic chest CT had large-airway pathology, including four patients with chronic, unexplained cough, discovered to have tracheobronchomalacia. Conclusion SGS and endobronchial disease occur in 10% and 6% of patients with GPA, respectively, and may occur without disease activity in other organs. Dynamic expiratory chest CT is a potential non-invasive screening test for large-airway involvement in GPA.

Objective To identify predictors of respiratory failure and to evaluate the therapeutic efficacy of plasma exchange (PE) and of rituximab versus cyclophosphamide in a cohort of patients with diffuse alveolar hemorrhage (DAH) secondary to antineutrophil cytoplasmic antibody–associated vasculitis (AAV) with or without respiratory failure. Methods We performed a single-center historical cohort study of all consecutive patients with AAV-associated DAH who were evaluated over a 16-year period. Logistic regression models were developed to examine the predictive role of the baseline clinical characteristics for the development of respiratory failure, and for the effect of PE and remission induction therapy on the main outcome (complete remission at 6 months). Results Seventy-three patients with DAH were identified, and 34 of them experienced respiratory failure. The degree of hypoxemia upon initial presentation, a higher percentage of neutrophils in the bronchoalveolar lavage fluid cell count, and higher C-reactive protein levels were independently associated with the development of respiratory failure. PE was not associated with achieving complete remission at 6 months, with an odds ratio (OR) of 0.49 (95% confidence interval [95% CI] 0.12–1.95) (P = 0.32). Rituximab treatment was independently associated with achieving complete remission at 6 months (OR 6.45 [95% CI 1.78–29], P = 0.003). Conclusion Our findings indicate that the most important predictor of respiratory failure in patients with DAH secondary to AAV is the degree of hypoxemia upon presentation. No clear benefit of the addition of PE to standard remission induction therapy was demonstrated. Complete remission by 6 months was achieved at a higher rate with rituximab than with cyclophosphamide in patients with DAH secondary to AAV, including those needing mechanical ventilation.

Objective.To evaluate the performance of the Birmingham Vasculitis Activity Score (BVAS) in the assessment of disease activity in giant cell arteritis (GCA).Methods.Patients with GCA enrolled in a prospective, multicenter, longitudinal study with symptoms of active vasculitis during any visit were included. Spearman’s rank correlation was used to explore the association of the BVAS with other measures of disease activity.Results.During a mean (SD) followup of 2.3 (1.6) years, symptoms of active GCA were present in 236 visits in 136 subjects (100 female, 74%). Median (range) BVAS1 (new/worse symptoms) was 1 (0–10) and median (range) BVAS2 (persistent symptoms) was 0 (0–5). Median (range) physician’s global assessment (PGA) was 4 (0–9) for disease activity in the past 28 days and 2 (0–9) for activity on the day of the visit. Important ischemic manifestations of active vasculitis not recorded by the BVAS included tongue/jaw claudication (27%), upper extremity claudication (15%), lower extremity claudication (5%), carotidynia (7%), and ischemic retinopathy (5%). During 25 visits (11%) with active disease, all symptoms of active vasculitis were placed in the “Other” category yet still resulted in a BVAS1 and BVAS2 of 0. BVAS1 moderately correlated with PGA for the past 28 days (Spearman’s correlation 0.50) and physician-rated disease activity for the past 28 days (Spearman’s correlation 0.46).Conclusion.The BVAS has limited utility in GCA. Patients with active GCA can have a BVAS of 0. Many important ischemic symptoms attributable to active vasculitis are not included in the composite score.

Background Prior work has shown that urinary soluble CD163 (usCD163) displays excellent biomarker characteristics for detection of active renal vasculitis using samples that included new diagnoses with highly active renal disease. This study focused on the use of usCD163 in the detection of the more clinically relevant state of mild renal flare and compared results of usCD163 testing directly to testing of urinary monocyte chemoattractant protein-1 (uMCP-1). Methods Patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV, n = 88) were identified within a serially sampled, longitudinal and multicentre cohort. Creatinine-normalized usCD163 and uMCP-1 levels were measured by enzyme-linked immunosorbent assay and, both alone and in combination, were compared between times of active renal AAV and during remission and/or active non-renal AAV. Results Samples from 320 study visits included times of active renal vasculitis (n = 39), remission (n = 233) and active extrarenal vasculitis (n = 48). Median creatinine levels were 0.9 mg/dL [interquartile range (IQR) 0.8–1.2] in remission and 1.4 mg/dL (IQR 1.0–1.8) during renal flare. usCD163 levels were higher in patients with active renal vasculitis compared with patients in remission and those with active extrarenal vasculitis, with median values of 162 ng/mmol (IQR 79–337), 44 (17–104) and 38 (7–76), respectively (P Conclusion A combination of usCD163 and uMCP-1 measurements appears to be useful in identifying the diagnosis of subtle renal vasculitis flare.

BACKGROUND/OBJECTIVES: Serum S100A8/S100A9 and S100A12 levels have been shown to be elevated in giant cell arteritis (GCA). This study aimed to determine if levels of serum S100 proteins perform as markers in a comparable fashion to standard markers of disease activity in large-vessel vasculitis. METHODS: Serum samples were obtained from the Vasculitis Clinical Research Consortium (VCRC) Longitudinal Prospective Cohort Study of GCA and Takayasu’s arteritis (TAK). A mixed effects model compared S100 proteins during active and inactive disease states. Receiver operating characteristic curves compared models using S100 proteins to models using ESR and CRP. RESULTS: There were 106 samples (50 during active disease) from patients with GCA and 32 samples (16 during active disease) from patients with TAK. In GCA, S100A8/S100A9 and S100A12 were significantly elevated during active disease (1445.6 ng/mL vs. 1095.7 ng/mL, p = 0.003;163.2 ng/mL vs. 116.6ng/mL, p=0.016, respectively). There were weak correlations between levels of S100 proteins and ESR or CRP. A model including S100A8/S100A9, S100A12, ESR, and CRP was a better indicator of disease activity compared to ESR and CRP together. In TAK, there were no significant differences between active and inactive disease for either the S100 proteins or ESR/CRP. CONCLUSIONS: Serum levels of S100A8/S100A9 and S100A12 are elevated during active disease and perform comparably to ESR and CRP as measures of disease activity in giant cell arteritis.

OBJECTIVE To examine the association between macrophage migration inhibitory factor (MIF) promoter polymorphisms and granulomatosis with polyangiitis (GPA) in human subjects, and to assess the role of MIF in a murine model of granulomatous vasculitis. METHODS The human study involved 1,077 patients with GPA and healthy controls whose serum was genotyped by capillary electrophoresis for the MIF -794 CATT5-8 promoter microsatellite (rs5844572). MIF promoter, CATT-length-dependent gene expression in response to β-glucan was assessed by gene reporter assays. In mouse studies, granulomatous disease was induced by injection of Candida albicans β-glucan into wild-type (WT) or Mif-knockout (Mif-KO) C57BL/6 mice and C57BL/6 mice transgenically overexpressing Mif in lung epithelium (Mif lung-Tg2.1). Mice were treated with a neutralizing anti-MIF antibody and analyzed for the density of pulmonary granulomas, expression of inflammatory chemokines, and frequency of mortality. RESULTS The percentage of human subjects carrying >5 CATT repeats in each MIF allele (high genotypic MIF expressers) was 60.2% among patients with GPA and 53.9% among healthy controls (adjusted P = 0.049). In response to granulomatous stimulation, human MIF gene expression increased proportionally with CATT length. Mif lung-Tg2.1 mice exhibited more pulmonary granulomas than WT mice, which in turn showed more granulomas than Mif-KO mice. A significantly higher percentage of Mif lung-Tg2.1 mice, compared to Mif-KO or WT mice, died when injected with Candida albicans β-glucan, and treatment of these mice with an anti-MIF monoclonal antibody protected against a lethal outcome. Levels of MIF-dependent neutrophil/macrophage chemokines were elevated in the bronchoalveolar lavage fluid or plasma of Mif lung-Tg2.1 mice. CONCLUSION Patients with GPA have an increased frequency of high MIF expression CATT alleles. Higher Mif expression increases the incidence of mortality and pulmonary granulomas in Mif lung-Tg2.1 mice, while anti-MIF treatment protects these mice against death. Blockade of MIF in high genotypic MIF expressers may therefore offer a selective pharmacologic therapy for GPA.