Risk of relapse of ANCA-associated vasculitis among patients homozygous for the proteinase 3 gene Val119Ile polymorphism.

BACKGROUND: The 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. METHODS: DNA 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-Ile119 or PRTN3-Val119. RESULTS: Whole 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-Val119 and 13 homozygous for PRTN3-Ile119. The frequency of severe flares at 18 months in homozygous PRTN3-Ile119 was significantly higher when compared with homozygous PRTN3-Val119 (46.2% vs 19.6%, p=0.048). Multivariate analysis identified homozygous PR3-Ile119 as main predictor of severe relapse (HR 4.67, 95% CI 1.16 to 18.86, p=0.030). CONCLUSION: In 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.

Autoreactive Plasmablasts After B Cell Depletion With Rituximab and Relapses in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis.

OBJECTIVE: Autoreactive B cells are responsible for antineutrophil cytoplasmic antibody (ANCA) production in ANCA-associated vasculitis (AAV). Rituximab (RTX) depletes circulating B cells, including autoreactive B cells. We aimed to evaluate changes and associations with relapse of the circulating autoreactive B cell pool following therapeutic B cell depletion in AAV. METHODS: Sequential flow cytometry was performed on 148 samples of peripheral blood mononuclear cells from 23 patients with proteinase 3 (PR3)-ANCA-positive AAV who were treated with RTX for remission induction and monitored after stopping therapy during long-term follow-up in a prospective clinical trial. PR3 was used as a ligand to target autoreactive PR3-specific (PR3+) B cells. B cell recurrence was considered as the first blood sample with ≥10 B cells/µl after RTX treatment. RESULTS: At B cell recurrence, PR3+ B cell frequency among B cells was higher than baseline (P < 0.01). Within both PR3+ and total B cells, frequencies of transitional and naive subsets were higher at B cell recurrence than at baseline, while memory subsets were lower (P < 0.001 for all comparisons). At B cell recurrence, frequencies of B cells and subsets did not differ between patients who experienced relapse and patients who remained in remission. In contrast, the plasmablast frequency within the PR3+ B cell pool was higher in patients who experienced relapse and associated with a shorter time to relapse. Frequencies of PR3+ plasmablasts higher than baseline were more likely to be found in patients who experienced relapse within the following 12 months compared to those in sustained remission (P < 0.05). CONCLUSION: The composition of the autoreactive B cell pool varies significantly following RTX treatment in AAV, and early plasmablast enrichment within the autoreactive pool is associated with future relapses.

Activation of a Latent Epitope Causing Differential Binding of Antineutrophil Cytoplasmic Antibodies to Proteinase 3.

OBJECTIVE: Proteinase 3 (PR3) is the major antigen for antineutrophil cytoplasmic antibodies (ANCAs) in the systemic autoimmune vasculitis, granulomatosis with polyangiitis (GPA). PR3-targeting ANCAs (PR3-ANCAs) recognize different epitopes on PR3. This study was undertaken to study the effect of mutations on PR3 antigenicity. METHODS: The recombinant PR3 variants, iPR3 (clinically used to detect PR3-ANCAs) and iHm5 (containing 3 point mutations in epitopes 1 and 5 generated for epitope mapping studies) immunoassays and serum samples from patients enrolled in ANCA-associated vasculitis (AAV) trials were used to screen for differential PR3-ANCA binding. A patient-derived monoclonal ANCA 518 (moANCA518) that selectively binds to iHm5 within the mutation-free epitope 3 and is distant from the point mutations of iHm5 was used as a gauge for remote epitope activation. Selective binding was determined using inhibition experiments. RESULTS: Rather than reduced binding of PR3-ANCAs to iHm5, we found substantially increased binding of the majority of PR3-ANCAs to iHm5 compared to 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. CONCLUSION: The preferential binding of PR3-ANCAs from patients, such as 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 MCPR2. This previously unrecognized characteristic of PR3-ANCA interactions with its target antigen has implications for studying antibody-mediated autoimmune diseases, understanding variable performance characteristics of immunoassays, and design of potential novel treatment approaches.

Serum Biomarkers of Disease Activity in Longitudinal Assessment of Patients with ANCA-Associated Vasculitis.

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-2Rα 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.

Circulating autoreactive proteinase 3+ B cells and tolerance checkpoints in ANCA-associated vasculitis.

BACKGROUNDLittle 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.METHODSMulticolor 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).RESULTSThe 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).CONCLUSIONThis 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 registrationClinicalTrials.gov NCT00104299.FundingThe Vasculitis Foundation, the National Institute of Allergy and Infectious Diseases of the NIH, and the Mayo Foundation for Education and Research.

Fc receptor-like 5 and anti-CD20 treatment response in granulomatosis with polyangiitis and microscopic polyangiitis.

BACKGROUNDBaseline expression of FCRL5, a marker of naive and memory B cells, was shown to predict response to rituximab (RTX) in rheumatoid arthritis. This study investigated baseline expression of FCRL5 as a potential biomarker of clinical response to RTX in granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA).METHODSA previously validated quantitative PCR-based (qPCR-based) platform was used to assess FCRL5 expression in patients with GPA/MPA (RAVE trial, NCT00104299).RESULTSBaseline FCRL5 expression was significantly higher in patients achieving complete remission (CR) at 6, 12, and 18 months, independent of other clinical and serological variables, among those randomized to RTX but not cyclophosphamide-azathioprine (CYC/AZA). Patients with baseline FCRL5 expression ≥ 0.01 expression units (termed FCRL5hi) exhibited significantly higher CR rates at 6, 12, and 18 months as compared with FCRL5lo subjects (84% versus 57% [P = 0.016], 68% versus 40% [P = 0.02], and 68% versus 29% [P = 0.0009], respectively).CONCLUSIONOur data taken together suggest that FCRL5 is a biomarker of B cell lineage associated with increased achievement and maintenance of complete remission among patients treated with RTX and warrant further investigation in a prospective manner.FUNDINGThe analysis for this study was funded by Genentech Inc.

Combined Brain/Heart Magnetic Resonance Imaging in Systemic Lupus Erythematosus.

Cardiovascular Disease (CVD) in Systemic Lupus Erythematosus (SLE) and Neuropsychiatric SLE (NPSLE) has an estimated prevalence of 50% and 40%, respectively and both constitute major causes of death among SLE patients. In this review, a combined brain/heart Magnetic Resonance Imaging (MRI) for SLE risk stratification has been proposed. The pathophysiologic background of NPSLE includes microangiopathy, macroscopic infarcts and accelerated atherosclerosis. Classic brain MRI findings demonstrate lesions suggestive of NPSLE in 50% of the NPSLE cases, while advanced MRI indices can detect pre-clinical lesions in the majority of them, but their clinical impact still remains unknown. Cardiac involvement in SLE includes myo-pericarditis, valvular disease/endocarditis, Heart Failure (HF), coronary macro-microvascular disease, vasculitis and pulmonary hypertension. Classic and advanced Cardiovascular Magnetic Resonance (CMR) indices allow function and tissue characterization for early diagnosis and treatment follow-up of CVD in SLE. Although currently, there are no clinical data supporting the combined use of brain/heart MRI in asymptomatic SLE, it may have a place in cases with clinical suspicion of brain/heart involvement, especially in patients at high risk for CVD/stroke such as SLE with antiphospholipid syndrome (SLE/APS), in whom concurrent cardiac and brain lesions have been identified. Furthermore, it may be of value in SLE with multi-organ involvement, NPSLE with concurrent cardiac involvement, and recent onset of arrhythmia and/or heart failure.

The association of serum interleukin-6 levels with clinical outcomes in antineutrophil cytoplasmic antibody-associated vasculitis.

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 (rs = 0.36,p < 0.01), but not with levels of myeloperoxidase (MPO)-ANCA (rs = -0.17,p = 0.47). Higher baseline sIL-6 levels were associated with PR3-ANCA positivity, fever, pulmonary nodules/cavities, conductive deafness, and absence of urinary red blood cell casts (p < 0.05). Baseline sIL6 levels did not predict CR at month 6 (p = 0.71), and the median sIL-6 level declined from baseline with induction therapy, regardless of CR achievement. An increase in sIL-6 during CR was a predictor for subsequent severe relapse in RTX-treated patients (hazard ratio (HR):7.24,p = 0.01), but not in CYC/AZA-treated patients (HR:0.62,p = 0.50). In contrast, a sIL-6 increase did not predict B cell repopulation or ANCA titer increase in either treatment arm (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.

Association of Pulmonary Hemorrhage, Positive Proteinase 3, and Urinary Red Blood Cell Casts With Venous Thromboembolism in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis.

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

Disease Activity, Antineutrophil Cytoplasmic Antibody Type, and Lipid Levels in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis.

OBJECTIVE: Patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) have an elevated risk of cardiovascular disease (CVD). This study was undertaken to develop a clearer understanding of the association between changes in disease activity and lipid levels in AAV, which may inform CVD risk stratification in this population. METHODS: Lipid levels were assessed in stored serum samples (obtained at baseline and month 6) from the Rituximab for ANCA-Associated Vasculitis (RAVE) trial, which randomized patients to receive either rituximab or cyclophosphamide followed by azathioprine. Paired t-tests and multivariable linear regression were used to assess changes in lipid levels. RESULTS: Of the 142 patients with serum samples available, the mean ± SD age was 52.3 ± 14.7 years, 72 (51%) were male, 95 (67%) were proteinase 3 (PR3)-ANCA positive, 72 (51%) had received a new diagnosis of AAV, and 75 (53%) were treated with rituximab. Several lipid levels increased between baseline and month 6, including total cholesterol (+12.4 mg/dl [95% confidence interval (95% CI) +7.1, +21.0]), low-density lipoprotein (+10.3 mg/dl [95% CI +6.1, +17.1]), and apolipoprotein B (+3.5 mg/dl [95% CI +1.0, +8.3]). These changes were observed among newly diagnosed and PR3-ANCA-positive patients but not among those with relapsing disease or myeloperoxidase-ANCA-positive patients. There was no difference in change in lipid levels between rituximab-treated patients and cyclophosphamide-treated patients. Changes in lipid levels correlated with changes in erythrocyte sedimentation rate but not with other inflammatory markers or glucocorticoid exposure. CONCLUSION: Lipid levels increased during remission induction among patients with newly diagnosed AAV and those who were PR3-ANCA positive. Disease activity and ANCA type should be considered when assessing lipid profiles to stratify CVD risk in patients with AAV.

The net effect of ANCA on neutrophil extracellular trap formation.

The formation of neutrophil extracellular traps induced by antineutrophil cytoplasmic autoantibodies has been implicated in the pathogenesis of antineutrophil cytoplasmic autoantibody-associated vasculitis. Kraaij et al. now provide evidence that excessive neutrophil extracellular trap formation in vitro induced by sera from patients with antineutrophil cytoplasmic autoantibody-associated vasculitis is associated with active disease but is not dependent on the presence of antineutrophil cytoplasmic autoantibodies.

Brief Report: Circulating Cytokine Profiles and Antineutrophil Cytoplasmic Antibody Specificity in Patients With Antineutrophil Cytoplasmic Antibody-Associated Vasculitis.

OBJECTIVE: To evaluate circulating cytokine profiles in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV), classified by antineutrophil cytoplasmic antibody (ANCA) specificity (proteinase 3 ANCA [PR3-ANCA] versus myeloperoxidase ANCA [MPO-ANCA]) or by clinical diagnosis (granulomatosis with polyangiitis [GPA] versus microscopic polyangiitis [MPA]). METHODS: A panel of 29 cytokines was tested in 186 patients with active AAV at inclusion into the Rituximab in AAV trial. Cytokine concentrations were compared between groups within each classification system. Multivariable analyses adjusted for age, sex, and renal insufficiency were performed, with each biomarker as a dependent variable and ANCA specificity and clinical diagnosis as explanatory variables of interest. RESULTS: Levels of 9 circulating cytokines (interleukin-6 [IL-6], granulocyte-macrophage colony-stimulating factor [GM-CSF], IL-15, IL-18, CXCL8/IL-8, CCL-17/thymus and activation-regulated chemokine [TARC], IL-18 binding protein [IL-18 BP], soluble IL-2 receptor α [sIL-2Rα], and nerve growth factor ß [NGFß]) were significantly higher in PR3-AAV than MPO-AAV, 4 cytokines (sIL6R, soluble tumor necrosis factor receptor type II [sTNFRII], neutrophil gelatinase-associated lipocalin [NGAL], and soluble intercellular adhesion molecule 1 [sICAM-1]) were higher in MPO-AAV than in PR3-AAV, 6 cytokines (IL-6, GM-CSF, IL-15, IL-18, sIL-2Rα, and NGFß) were higher in GPA than in MPA, and 3 cytokines (osteopontin, sTNFRII, and NGAL) were higher in MPA than in GPA (all P < 0.05). For nearly all cytokines, the difference between PR3-AAV and MPO-AAV was larger than that between GPA and MPA. The multivariate analysis showed that 8 cytokines (IL-15, IL-8, IL-18 BP, NGF-ß, sICAM-1, TARC, osteopontin, and kidney injury molecule 1 (P < 0.05) distinguished patients with AAV better (lower P values and larger effect sizes) when grouped by ANCA specificity than by clinical diagnosis. CONCLUSION: Distinct cytokine profiles were identified for PR3-AAV versus MPO-AAV and for GPA versus MPA. Differences in these circulating immune mediators are more strongly associated with ANCA specificity than with clinical diagnosis, suggesting that heterogeneity in the AAV subtypes extends beyond clinical phenotypes.

Combined brain and heart magnetic resonance imaging in systemic vasculitides: fiction or real need?

Systemic vasculitides (SVs) is a group of diseases characterised by inflammation/necrosis of the blood vessel wall in various organs. Simultaneous brain and heart involvement is a cause of increased morbidity/mortality in SV. We aimed to present evidence of concurrent brain/heart involvement in SV and the role of a combined brain/heart magnetic resonance imaging (MRI) in their risk stratification. Cerebral vasculitis (CV) can be presented as focal deficits, seizures, headache, neuropsychiatric manifestations or cognitive dysfunction and cardiovascular disease (CVD) as myocardial/vascular inflammation, perfusion/function defects and fibrosis. MRI is a non-invasive, non-radiating technique that allows the reliable identification of intraparenchymal brain lesions and the detection of myocardial/vascular inflammation and fibrosis. However, its use in SV is currently hampered by high cost, lack of availability/expertise and lack of awareness among the clinicians. Although there are no clinical data supporting the combined use of brain/heart MRI in asymptomatic SV, it would be called for in cases with clinical suspicion of brain/heart involvement, especially in those at high risk for CVD/stroke such as SLE/APS. Furthermore, it may be of value in SV with multi-organ involvement, cognitive dysfunction or other neuropsychiatric symptoms with concurrent cardiac involvement, presenting as typical or atypical symptoms with normal routine cardiac evaluation, new onset of arrhythmia and/or HF.

Review: What Is the Current Evidence for Disease Subsets in Giant Cell Arteritis?

Giant cell arteritis (GCA) is an autoimmune vasculitis affecting large and medium-sized arteries. Ample evidence indicates that GCA is a heterogeneous disease in terms of symptoms, immune pathology, and response to treatment. In the current review, we discuss the evidence for disease subsets in GCA. We describe clinical and immunologic characteristics that may impact the risk of cranial ischemic symptoms, relapse rates, and long-term glucocorticoid requirements in patients with GCA. In addition, we discuss both proven and putative immunologic targets for therapy in patients with GCA who have an unfavorable prognosis. Finally, we provide recommendations for further research on disease subsets in GCA.

The Utility of Urinalysis in Determining the Risk of Renal Relapse in ANCA-Associated Vasculitis.

BACKGROUND AND OBJECTIVES: The significance of persistent hematuria or proteinuria in patients with ANCA-associated vasculitis who are otherwise in clinical remission is unclear. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A post hoc analysis was conducted using participants enrolled in two randomized, placebo-controlled clinical trials who had active GN due to ANCA-associated vasculitis, had positive ANCA, and achieved remission by month 6. Dipstick and microscopic urinalyses were performed at each visit. Persistent hematuria or proteinuria for at least 6 months and the cumulative duration of hematuria were examined. Renal relapse was defined as new or worsening red blood cell casts and/or worsening kidney function according to the Birmingham Vasculitis Activity Score for Granulomatosis with Polyangiitis. RESULTS: There were 149 patients included in this study: 42% had persistent hematuria, and 43% had persistent proteinuria beyond 6 months. Persistent hematuria was associated with a significantly higher risk of relapse, even after adjusting for potential confounders (subdistribution hazard ratio, 3.99; 95% confidence interval, 1.20 to 13.25; P=0.02); persistent proteinuria was not associated with renal relapse (subdistribution hazard ratio, 1.44; 95% confidence interval, 0.47 to 4.42; P=0.53). Furthermore, greater cumulative duration of hematuria was significantly associated with a higher risk of renal relapse (adjusted subdistribution hazard ratio, 1.08 per each month; 95% confidence interval, 1.03 to 1.12; P<0.01). The median time to renal relapse was 22 months. CONCLUSIONS: In patients with ANCA-associated vasculitis and kidney involvement who achieve remission after induction therapy, the presence of persistent hematuria, but not proteinuria, is a significant predictor of future renal relapse.

Pharmacokinetics of rituximab and clinical outcomes in patients with anti-neutrophil cytoplasmic antibody associated vasculitis.

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/m2). 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.

Towards precision medicine in ANCA-associated vasculitis.

ANCA-associated vasculitis (AAV) is characterized by inflammation and destruction of small and medium-sized vessels. Current management strategies for AAV have been validated in large groups of patients. However, recent insights indicate that distinct patient subsets may actually exist within AAV, thereby justifying the development of more personalized treatment strategies. In this review, we discuss current evidence for a better classification of AAV based on ANCA type. We describe how thus defined categories of AAV patients may differ in genetic background, clinical presentation, immune pathology, response to treatment and disease outcome. We also explore how these insights may provide a rationale for targeted treatments in different categories of AAV patients. Finally, we provide recommendations on how to further establish precision medicine in AAV.

The BVAS is an independent predictor of cardiovascular events and cardiovascular disease-related mortality in patients with ANCA-associated vasculitis: A study of 504 cases in a single Chinese center.

BACKGROUND: Cardiovascular diseases (CVD) are the major causes of death in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) during long-term follow-up. This study investigated risk factors for cardiovascular events (CVE) and CVD-related mortality in Chinese AAV patients. METHODS: Five hundred and four AAV patients in our center were retrospectively included. The predictive value of variables associated with CVE- and CVD-related mortality were analyzed. RESULTS: During follow-up of a median duration of 38 (range 1-228) months, 117 out of 504 patients had CVE. Independent predictors of CVE were age [increase by 10 years, hazard ratio (HR) 1.436, 95% confidence interval (CI) 1.187-1.736, p = 0.000], systolic blood pressure (increase by 10mmHg, HR = 1.171, 95% CI: 1.038-1.321, p = 0.010), estimated glomerular filtration rate (eGFR) (increase by 1mL/min/1.73m2, HR = 0.992, 95% CI: 0.984-0.999, p = 0.020), high-density lipoprotein level (HR = 0.530, 95% CI: 0.303-0.926, p = 0.026) and the Birmingham Vasculitis Activity Score (BVAS) (HR = 1.039, 95% CI: 1.011-1.067, p = 0.006). Forty-one patients died from CVD. Independent predictors of CVD-related mortality were age (increase by 10 years; HR = 1.732, 95% CI: 1.237-2.426, p = 0.001), eGFR (increase by 1mL/min/1.73m2, HR = 0.984, 95% CI: 0.970-0.997, p = 0.016), pre-existing CV disease (HR = 2.872, 95% CI: 1.503-5.487, p = 0.001) and BVAS (HR = 1.064, 95% CI: 1.018-1.113, p = 0.006). We further analyzed CVE- and CVD-related mortality after 2 years since diagnosis, and found BVAS were still an independent predictor of CVE- and CVD-related mortality. CONCLUSION: Besides the traditional risk factors, BVAS at presentation was an independent predictor of CVE- and CVD-related mortality in patients with AAV.

Genetic loci of Staphylococcus aureus associated with anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides.

The proteinase 3 (PR3)-positive anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) granulomatosis with polyangiitis (GPA) has been associated with chronic nasal S. aureus carriage, which is a risk factor for disease relapse. The present study was aimed at comparing the genetic make-up of S. aureus isolates from PR3-ANCA-positive GPA patients with that of isolates from patients suffering from myeloperoxidase (MPO)-ANCA-positive AAV, and isolates from healthy controls. Based on a DNA microarray-based approach, we show that not only PR3-ANCA-positive GPA patients, but also MPO-ANCA-positive AAV patients mainly carried S. aureus types that are prevalent in the general population. Nonetheless, our data suggests that MPO-ANCA-associated S. aureus isolates may be distinct from healthy control- and PR3-ANCA-associated isolates. Furthermore, several genetic loci of S. aureus are associated with either PR3-ANCA- or MPO-ANCA-positive AAV, indicating a possible role for pore-forming toxins, such as leukocidins, in PR3-ANCA-positive GPA. Contrary to previous studies, no association between AAV and superantigens was detected. Our findings also show that a lowered humoral immune response to S. aureus is common for PR3-ANCA- and MPO-ANCA-positive AAV. Altogether, our observations imply that the presence or absence of particular virulence genes of S. aureus isolates from AAV patients contributes to disease progression and/or relapse.

Position paper: Revised 2017 international consensus on testing of ANCAs in granulomatosis with polyangiitis and microscopic polyangiitis.

Anti-neutrophil cytoplasmic antibodies (ANCAs) are valuable laboratory markers used for the diagnosis of well-defined types of small-vessel vasculitis, including granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). According to the 1999 international consensus on ANCA testing, indirect immunofluorescence (IIF) should be used to screen for ANCAs, and samples containing ANCAs should then be tested by immunoassays for proteinase 3 (PR3)-ANCAs and myeloperoxidase (MPO)-ANCAs. The distinction between PR3-ANCAs and MPO-ANCAs has important clinical and pathogenic implications. As dependable immunoassays for PR3-ANCAs and MPO-ANCAs have become broadly available, there is increasing international agreement that high-quality immunoassays are the preferred screening method for the diagnosis of ANCA-associated vasculitis. The present Consensus Statement proposes that high-quality immunoassays can be used as the primary screening method for patients suspected of having the ANCA-associated vaculitides GPA and MPA without the categorical need for IIF, and presents and discusses evidence to support this recommendation.