Value of ANCA measurements during remission to predict a relapse of ANCA-associated vasculitis--a meta-analysis

Avacopan's potential to decrease MPO-ANCA titres concurrent with ameliorated activity in ANCA-associated vasculitis

Avacopan, an orally administered C5a receptor antagonist, is effective in microscopic polyangiitis via the inhibition of neutrophil priming induced by C5a. However, the exact effect of avacopan on the production of myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) is yet to be clearly established. This report presents a microscopic polyangiitis patient without major organ damage where high levels of MPO-ANCA persisted with high-dose steroid therapy and azathioprine, but the addition of avacopan led to a reduction in MPO-ANCA titres. The present case implies that avacopan-mediated inhibition of C5a may lead to a reduction in MPO-ANCA levels, thereby potentially ameliorating the pathophysiology of ANCA-associated vasculitis. Nevertheless, the impact of avacopan on MPO-ANCA production cannot be asserted solely based on this report; therefore, further examination is necessary through subgroup analysis using data from larger-scale studies.

[Eosinophilic granulomatosis with polyangiitis: a review article]

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare form of ANCA-associated vasculitis (AAV) within the group of small vessel vasculitides. It is defined by vasculitis of small and medium-sized vessels with granulomatous inflammation and blood and tissue eosinophilia. Almost all patients have allergic symptoms with bronchial asthma and rhinosinusitis symptoms. Further clinical manifestations vary depending on the localisation, severity, and type of disease manifestation. Eosinophilic infiltration and inflammation may result in rhinosinusitis, pneumonitis, gastrointestinal involvement, and cardiomyopathy. The latter, in particular, is associated with a worse prognosis. As a necrotising pauci-immune small-vessel vasculitis, EGPA, similar to the other AAVs, can cause pulmonary infiltrates with alveolar haemorrhage, glomerulonephritis, cutaneous vasculitis with purpura as well as central and peripheral neurologic injuries. The presence of perinuclear ANCA (pANCA) with specificity against myeloperoxidase (MPO) is observed in approximately one-third of patients but is not specific to EGPA. MPO-ANCA-positive patients are more likely to have peripheral neurologic involvement and glomerulonephritis, whereas ANCA-negative patients are more likely to have cardiac and pulmonary involvement. What is frequently challenging in the clinical routine is to differentiate EGPA from the hypereosinophilic syndrome (HES). The therapeutic approach to EGPA depends on whether the severity of the disease is potentially organ or life-threatening. For severe forms of EGPA, acute therapy mainly includes glucocorticoids in combination with cyclophosphamide. Rituximab has come to be mentioned as an alternative treatment option in the guidelines. Various immunosuppressive therapies are available for remission maintenance. In EGPA without severe organ involvement, IL-5 blockade with mepolizumab is an approved treatment.

Computable phenotype for real-world, data-driven retrospective identification of relapse in ANCA-associated vasculitis

OBJECTIVE

ANCA-associated vasculitis (AAV) is a relapsing-remitting disease, resulting in incremental tissue injury. The gold-standard relapse definition (Birmingham Vasculitis Activity Score, BVAS>0) is often missing or inaccurate in registry settings, leading to errors in ascertainment of this key outcome. We sought to create a computable phenotype (CP) to automate retrospective identification of relapse using real-world data in the research setting.

METHODS

We studied 536 patients with AAV and >6 months follow-up recruited to the Rare Kidney Disease registry (a national longitudinal, multicentre cohort study). We followed five steps: (1) independent encounter adjudication using primary medical records to assign the ground truth, (2) selection of data elements (DEs), (3) CP development using multilevel regression modelling, (4) internal validation and (5) development of additional models to handle missingness. Cut-points were determined by maximising the F1-score. We developed a web application for CP implementation, which outputs an individualised probability of relapse.

RESULTS

Development and validation datasets comprised 1209 and 377 encounters, respectively. After classifying encounters with diagnostic histopathology as relapse, we identified five key DEs; DE1: change in ANCA level, DE2: suggestive blood/urine tests, DE3: suggestive imaging, DE4: immunosuppression status, DE5: immunosuppression change. F1-score, sensitivity and specificity were 0.85 (95% CI 0.77 to 0.92), 0.89 (95% CI 0.80 to 0.99) and 0.96 (95% CI 0.93 to 0.99), respectively. Where DE5 was missing, DE2 plus either DE1/DE3 were required to match the accuracy of BVAS.

CONCLUSIONS

This CP accurately quantifies the individualised probability of relapse in AAV retrospectively, using objective, readily accessible registry data. This framework could be leveraged for other outcomes and relapsing diseases.

Clinical features and prognosis of ANCA-associated vasculitis patients who were double-seropositive for myeloperoxidase-ANCA and proteinase 3-ANCA

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) patients with dual positivity for proteinase 3-ANCA (PR3-ANCA) and myeloperoxidase-ANCA (MPO-ANCA) are uncommon. We aimed to investigate these idiopathic double-positive AAV patients' clinical features, histological characteristics, and prognosis. We reviewed all the electronic medical records of patients diagnosed with AAV to obtain clinical data and renal histological information from January 2010 to December 2020 in a large center in China. Patients were assigned to the MPO-AAV group or PR3-AAV group or idiopathic double-positive AAV group by ANCA specificity. We explored features of idiopathic double-positive AAV. Of the 340 patients who fulfilled the study inclusion criteria, 159 (46.76%) were female, with a mean age of 58.41 years at the time of AAV diagnosis. Similar to MPO-AAV, idiopathic double-positive AAV patients were older and had more severe anemia, lower Birmingham Vasculitis Activity Score (BVAS) and C-reactive protein (CRP) levels, less ear, nose, and throat (ENT) involvement, higher initial serum creatinine and a lower estimated glomerular filtration rate (eGFR) when compared with PR3-AAV (P < 0.05). The proportion of normal glomeruli of idiopathic double-positive AAV was the lowest among the three groups (P < 0.05). The idiopathic double-positive AAV patients had the worst remission rate (58.8%) among the three groups (P < 0.05). The relapse rate of double-positive AAV (40.0%) was comparable with PR3-AAV (44.8%) (P > 0.05). Although there was a trend toward a higher relapse rate of idiopathic double-positive AAV (40.0%) compared with MPO-AAV (23.5%), this did not reach statistical significance (P > 0.05). The proportion of patients who progressed to ESRD was 47.1% and 44.4% in the idiopathic double-positive AAV group and MPO-AAV group respectively, without statistical significance. Long-term patient survival also varied among the three groups (P < 0.05). Idiopathic double-positive AAV is a rare clinical entity with hybrid features of MPO-AAV and PR3-AAV. MPO-AAV is the "dominant" phenotype in idiopathic double-positive AAV.

Urinary CD4 + T Cells Predict Renal Relapse in ANCA-Associated Vasculitis

SIGNIFICANCE STATEMENT

Early identification of patients at risk of renal flares in ANCA vasculitis is crucial. However, current clinical parameters have limitations in predicting renal relapse accurately. This study investigated the use of urinary CD4 + T lymphocytes as a predictive biomarker for renal flares in ANCA vasculitis. This study, including urine samples from 102 patients, found that the presence of urinary CD4 + T cells was a robust predictor of renal relapse within a 6-month time frame, with a sensitivity of 60% and a specificity of 97.8%. The diagnostic accuracy of urinary CD4 + T cells exceeded that of ANCA titers, proteinuria, and hematuria. Monitoring urinary CD4 + T lymphocytes could help assess the risk of future renal relapse, enabling early preventive measures and tailored treatment strategies.

BACKGROUND

In ANCA-associated vasculitis, there is a lack of biomarkers for predicting renal relapse. Urinary T cells have been shown to differentiate active GN from remission in ANCA-associated vasculitis, but their predictive value for renal flares remains unknown.

METHODS

The PRE-FLARED study was a prospective multicenter biomarker study including 102 individuals with ANCA-associated vasculitis in remission aimed to predict renal relapse by quantifying urinary CD4 + T-cell subsets using flow cytometry at baseline and monitoring clinical outcomes over a 6-month follow-up.

RESULTS

Among the participants, ten experienced renal relapses, two had non-renal flares, and 90 remained in stable remission. The median baseline urinary CD4 + T-cell count was significantly higher in patients who relapsed compared with those in remission. Receiver operating characteristic curve analysis of urinary CD4 + T-cell counts showed an area under the curve value of 0.88 for predicting renal flares, outperforming ANCA titers, hematuria, and proteinuria. Using a cutoff of 490 CD4 + T cells per 100 ml urine, the sensitivity and specificity in identifying patients with future renal flares were 60% and 97.8%, respectively. In a post hoc analysis, combining urinary CD4 + T-cell counts with proteinase-3 ANCA levels suggested improved predictive performance in the PR3 + subgroup. In addition, the number of urinary CD4 + T cells showed a limited correlation with a decline in GFR and an increase in proteinuria over the follow-up period.

CONCLUSIONS

This study concluded that urinary CD4 + T-cell counts could identify patients with ANCA-associated vasculitis at a substantial risk of renal relapse within 6 months. Combining these counts with ANCA levels further improved the prediction of relapse.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Urinary T Lymphocytes Predict Renal Flares in Patients With Inactive ANCA-associated Glomerulonephritis (PRE-FLARED), NCT04428398 .

Anti-LAMP-2 Antibody Seropositivity in Children with Primary Systemic Vasculitis Affecting Medium- and Large-Sized Vessels

Chronic primary systemic vasculitis (PSV) comprises a group of heterogeneous diseases that are broadly classified by affected blood vessel size, clinical traits and the presence (or absence) of anti-neutrophil cytoplasmic antibodies (ANCA) against proteinase 3 (PR3) and myeloperoxidase (MPO). In small vessel vasculitis (SVV), ANCA are not present in all patients, and they are rarely detected in patients with vasculitis involving medium (MVV) and large (LVV) blood vessels. Some studies have demonstrated that lysosome-associated membrane protein-2 (LAMP-2/CD107b) is a target of ANCA in SVV, but its presence and prognostic value in childhood MVV and LVV is not known. This study utilized retrospective sera and clinical data obtained from 90 children and adolescents with chronic PSV affecting small (SVV, n = 53), medium (MVV, n = 16), and large (LVV, n = 21) blood vessels. LAMP-2-ANCA were measured in time-of-diagnosis sera using a custom electrochemiluminescence assay. The threshold for seropositivity was established in a comparator cohort of patients with systemic autoinflammatory disease. The proportion of LAMP-2-ANCA-seropositive individuals and sera concentrations of LAMP-2-ANCA were assessed for associations with overall and organ-specific disease activity at diagnosis and one-year follow up. This study demonstrated a greater time-of-diagnosis prevalence and sera concentration of LAMP-2-ANCA in MVV (52.9% seropositive) and LVV (76.2%) compared to SVV (45.3%). Further, LAMP-2-ANCA-seropositive individuals had significantly lower overall, but not organ-specific, disease activity at diagnosis. This did not, however, result in a greater reduction in disease activity or the likelihood of achieving inactive disease one-year after diagnosis. The results of this study demonstrate particularly high prevalence and concentration of LAMP-2-ANCA in chronic PSV that affects large blood vessels and is seronegative for traditional ANCA. Our findings invite reconsideration of roles for autoantigens other than MPO and PR3 in pediatric vasculitis, particularly in medium- and large-sized blood vessels.

Unexpected Relapse: Insights Into Granulomatosis With Polyangiitis

Granulomatosis with polyangiitis (GPA) is a rare vasculitis that can pose a significant mortality risk given its multiorgan involvement and is the most common of the three anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitides. Cardinal pathological features include necrotizing granulomas of the respiratory tract, small and medium vessel vasculitis, and glomerulonephritis. Early treatment is imperative to reduce permanent organ damage such as end-stage kidney disease. We describe the first case of GPA relapse 38 years after the initial pulmonary presentation. The patient previously had isolated lung involvement with preserved renal function, but presented with an acute kidney injury, uremia, and several constitutional symptoms. The patient was treated with corticosteroids and intermittent hemodialysis and initiated on immunosuppressants; the clinical course is highlighted by eventual renal recovery. Our purpose is to highlight the importance of treating patients to complete immunological recovery, particularly in GPA vasculitis, to prevent unnecessary relapse and further loss of renal function.

Maintenance of remission of ANCA vasculitis by rituximab based on B cell repopulation versus serological flare: a randomised trial

OBJECTIVE

To compare two long-term remission maintenance strategies for antineutrophil cytoplasmic antibody (ANCA) vasculitis.

METHODS

We conducted a prospective, single-centre, open-label, randomised controlled trial of patients with ANCA vasculitis in remission after completing at least 2 years of fixed-schedule rituximab. In the B cell arm, rituximab was reinfused upon B cell repopulation; in the ANCA arm, rituximab was reinfused upon significant rise in ANCA level. Evaluations were conducted every 3 months. The primary endpoint was clinical relapse, defined as a modified BVAS/WG >0 by 36 months. Secondary endpoints included serious adverse events (SAEs) and rituximab exposure.

RESULTS

115 patients were enrolled. Median follow-up time was 4.1 years (IQR 2.5-5.0). By Kaplan-Meier analysis, 4.1% (95% CI 1.0 to 15.6) of patients had a clinical relapse in the B cell arm, compared with 20.5% (95% CI 11.9 to 34.1) in the ANCA arm, at 3 years after study entry (log-rank p=0.045). Total SAEs, including infectious SAEs, and deaths did not differ. The number of SAEs due to COVID-19 was higher in the B cell arm (p=0.049). In the B cell arm, patients received a mean of 3.6 (SD 2.4) infusions (3.6 g) per person over the median study follow-up time of 4.1 years, compared with 0.5 (SD 1.4) infusions (0.5 g) per patient in the ANCA arm (p<0.001).

CONCLUSIONS

Rituximab dosed for B cell repopulation results in fewer clinical relapses than when dosed for a rise in ANCA level in maintenance of remission for ANCA vasculitis. Overall safety was equivalent; SAEs due to COVID-19 and rituximab exposure were higher with the B cell strategy.

TRIAL REGISTRATION NUMBER

NCT02749292.

Non-invasive biomarkers of disease activity and organ damage in ANCA-associated vasculitis: a systematic review

BACKGROUND

In anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), histopathological assessment of affected tissue is often necessary for diagnosis and assessment of disease extent. There is a requirement for validated non-invasive biomarkers to avoid the need for serial tissue biopsies.

METHODS

A systematic review of scientific databases from 2012 until present was performed to identify studies fulfilling the inclusion criteria. Studies were assessed for quality using the Strengthening the Reporting of Observational Studies in Epidemiology checklist for cohort, case-control and cross-sectional studies and the Risk of Bias Assessment tool for Non-randomised Studies, or the Cochrane Risk of Bias tool 2.0 for randomised controlled trials. A descriptive synthesis of the data for non-invasive (blood-based or urinary) biomarkers of AAV-related disease activity and organ damage was performed.

RESULTS

Twenty-two high quality studies were included. These articles reported the value of blood-based and urinary biomarkers including anti-neutrophil cytoplasmic antibodies, immune cells, complement factors, gene expression profiles, cytokines, chemokines and other proteins in the assessment of disease activity and/or organ damage in patients with AAV. Many of these biomarkers involve the alternative complement pathway, neutrophil activation and macrophage activation.

CONCLUSION

This is the first contemporary systematic review synthesising the value of non-invasive biomarkers of AAV-related disease activity and organ damage. The incorporation of individual markers in combined biomarker profiles might enhance clinical decision-making. Many unmet needs were identified; few studies involve oeosinophilic granulomatosis with polyangiitis and patients with childhood-onset AAV. Further validation of the candidate biomarkers is warranted in large prospective studies to bridge the existing knowledge gaps and apply precision health to systemic vasculitis.

Risk factors for hypogammaglobulinemia and association with relapse and severe infections in ANCA-associated vasculitis: A cohort study

OBJECTIVES

B-cell depletion induced by rituximab (RTX) in ANCA-associated vasculitis (AAV) is a risk factor for hypogammaglobulinemia. Aggregating data on gammaglobulin levels kinetics during RTX and its association with the risk of relapse and severe infection is of interest.

METHODS

Gammaglobulin levels were collected before induction therapy and during RTX maintenance therapy. We used different definitions of gammaglobulin decline: 1/gammaglobulin levels <6 g/L after induction; 2/>25 % decline in gammaglobulin levels between induction and maintenance, and 3/both. Our primary objective was the impact of gammaglobulin decline on the risk of relapse and severe infections.

RESULTS

We included 98 patients. Patients with gammaglobulin level <6 g/L after induction and gammaglobulin decline >25 % were older (OR 3.9; 95%CI 1.1-16.1), had more frequently baseline gammaglobulin levels <10 g/L (OR 6.0; 95%CI 1.7-25.8) and received more frequent pulses of methylprednisolone at induction (OR 4.6; 95%CI 1.3-18.5). Severe infection-free survival was significantly poorer in patients with both gammaglobulin <6 g/L and gammaglobulin decline >25 % (adjusted HR 2.3; 95%CI 1.0-5.1) and in those who received pulses of methylprednisolone (HR 5.6; 95%CI 2.3-13.4). Gammaglobulin decline was in contrast not associated with the risk of relapse.

CONCLUSION

Older age, low gammaglobulin levels and pulses of methylprednisolone at induction increase the likelihood of gammaglobulin decline after induction therapy. Such decline was associated with an increased risk of severe infections but not lower risk of vasculitis relapse. Pulses of methylprednisolone at induction had an independent negative impact on gammaglobulin levels and the risk of severe infections.

Management of antineutrophil cytoplasmic antibody-associated vasculitis with glomerulonephritis as proposed by the ACR 2021, EULAR 2022 and KDIGO 2021 guidelines/recommendations

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

Serum calprotectin and renal function decline in ANCA-associated vasculitides: a post hoc analysis of MAINRITSAN trial

OBJECTIVE

Serum calprotectin appears to be an interesting biomarker associated with renal vascular disease activity in antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV). The aim of this study was to assess whether serum calprotectin levels can predict decline in renal function in AAV patients receiving maintenance therapy.

METHODS

Serum calprotectin levels were assessed at inclusion and month 6 in AAV patients, in complete remission after induction therapy, randomly assigned to rituximab or azathioprine. Renal function decline was defined as a 25% decrease in estimated glomerular filtration rate (eGFR) and a change in the eGFR category, or a decrease of 15 mL/min/1.73 m2. Relapse was defined as a Birmingham Vasculitis Activity Score >0 attributable to active vasculitis.

RESULTS

Seventy-six AAV were included. Serum calprotectin increased from baseline to month 6 in patients with renal function decline (7940 (-226.0, 28 691) ng/ml vs -4800 (-18 777, 3708) ng/ml; p<0.001). An increase of calprotectin level was associated with a higher risk of subsequent renal function decline even after adjustment (OR 6.50 (95% CI 1.7 to 24.9) p=0.006). A significantly higher risk of relapse was observed in proteinase 3- AAV patients with an increase of serum calprotectin levels (OR 5.6 (95% CI 1.0 to 31.2), p=0.03).

CONCLUSION

An increase in serum calprotectin by month 6 compared with inclusion during remission-maintenance therapy in AAV was associated with a higher risk of renal function decline in the following 12 months.

TRIAL REGISTRATION NUMBER

NCT00748644.

Basic Investigations in Pediatric Rheumatology

The spectrum of pediatric rheumatological disorders is diverse and they are important differential diagnoses in a variety of clinical scenarios. Basic investigations not only provide supporting evidence for the diagnosis of a rheumatological illness but also help in exclusion of other diseases as well as for monitoring the activity of disease. Among these, complete blood count, biochemical assays including tests for inflammatory response, urine analysis, and various autoantibodies are often used. In addition, depending on the clinical features, imaging and tissue biopsies are used to confirm the diagnosis.

[Diagnosis and therapy of granulomatosis with polyangiitis and microscopic polyangiitis-2023: consensus of the Austrian society of nephrology (ÖGN) and Austrian society of rheumatology (ÖGR)]

ANCA-associated vasculitides (AAV) are rare, complex systemic diseases that are often difficult to diagnose, because of unspecific clinical symptoms at presentation. However, the clinical course may be very dramatic and even life-threatening, necessitating prompt diagnosis and treatment.Therefore, it is important to increase disease awareness among physicians and support colleagues who are not confronted with these rare diseases on a regular basis. Here, the Austrian Society of Nephrology (ÖGN) and the Austrian Society of Rheumatology (ÖGR) provide a joint consensus on how to best diagnose and manage patients with granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA).

Optimal management of ANCA-associated vasculitis before and during pregnancy: current perspectives

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are a group of systemic vasculitis characterized by autoantibodies against neutrophil cytoplasmic antigens (proteinase 3 PR3-ANCA and myeloperoxidase MPO-ANCA) and inflammation of small vessels. AAV include the diagnosis Granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (EGPA), which share many clinical and pathological features. Immunomodulatory therapies have significantly improved prognosis during the last decade. Nevertheless, especially in undiagnosed and thus uncontrolled AAV mortality due to renal impairment or pulmonary haemorrhages is still high. AAV are rare in fertile women, as the typical age of manifestation is above 50 years but there are women with AAV who are or want to become pregnant. This review focusses on how to manage patients with AAV planning to become pregnant and during their pregnancy.

KDOQI US Commentary on the 2021 KDIGO Clinical Practice Guideline for the Management of Glomerular Diseases

The KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases represents the first update to this set of recommendations since the initial set of KDIGO guideline recommendations was published in 2012. The pace of growth in our molecular understanding of glomerular disease has quickened and a number of newer immunosuppressive and targeted therapies have been introduced since the original set of guideline recommendations, making such an update necessary. Despite these updates, many areas of controversy remain. In addition, further updates since the publication of KDIGO 2021 have occurred which this guideline does not encompass. With this commentary, the KDOQI work group has generated a chapter-by-chapter companion opinion article that provides commentary specific to the implementation of the KDIGO 2021 guideline in the United States.

Challenges of defining renal response in ANCA-associated vasculitis: call to action?

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

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.

New Insights into Pathogenesis and Treatment of ANCA-Associated Vasculitis: Autoantibodies and Beyond

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis is a group of rare systemic diseases affecting small-caliber vessels. The damage caused by AAV mainly involves the lung and kidneys. AAV includes three different types: granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). Although the different phenotypic forms of AAV share common features, recent studies have shown that there are significant differences in terms of pathogenetic mechanisms involving both the adaptive and innate immune systems. Advances in our understanding of pathogenesis have enabled the development of immuno-targeted therapies. This review illustrates the characteristics of the various forms of AAV and the new therapies available for this disease that can have lethal consequences if left untreated.

Diagnostic accuracy of antineutrophil cytoplasmic antibodies (ANCA) in predicting relapses of ANCA-associated vasculitis: systematic review and meta-analysis

Relapse in antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) is associated with significant morbidity and mortality. Utility of ANCA for prediction of relapses is still controversial. PubMed/MEDLINE, Scopus, and WebOfScience were searched, screened and confirmed for inclusion [PROSPERO No: CRD42020220308]. Studies measuring serial ANCA by ELISA or indirect immunofluorescence (IF), reporting relapses with sufficient data to calculate sensitivity and specificity were included. Diagnostic odds ratio (OR), sensitivity, specificity and likelihood ratios (LR) were synthesized using a bivariate mixed-effect regression model. Sub-group analysis included a comparison between ELISA and IIF, anti-myeloperoxidase (MPO) and -proteinase 3(PR3), and type of rise in ANCA. For meta-analysis of survival outcomes, hazard ratios were synthesized using a random-effect model. QUADAS-2 was used for assessing quality of studies, I² statistic for heterogeneity Begg's test for publication bias. 2946 abstracts and 43 full-texts were reviewed to identify 26 eligible studies that included 2623 patients with AAV and 848 relapses. Overall heterogeneity was high [I² = 99%] and the overall risk of bias was low to moderate. ANCA positivity by either ELISA or immunofluorescence for predicting relapse of AAV had a sensitivity of 0.70(95% CI 0.58-0.81), specificity of 0.66(0.55-0.76), positive LR of 2.1(1.6-42.7) and negative LR of 0.44(0.30-0.60). ELISA performed marginally better [OR: 5(3-7)] than IIF [OR: 4(2-9)] with similar sensitivity, specificity, PLR and NLR. The area under the curve for PR3 was 0.74(0.7-0.77), while that for MPO was not computed as the number of eligible studies was only three. In the survival analysis, the hazard ratio for relapse was 3.11(1.7-5.65). The meta-analysis shows modest accuracy of ANCA in predicting relapses of ANCA vasculitis and supports the use of serial ANCA monitoring as a biomarker for relapse.

Plasma exchange as an adjunctive therapy in anti-neutrophil cytoplasm antibody-associated vasculitis

INTRODUCTION

We summarize evidence for the role of therapeutic plasma exchange (TPE) in the treatment of anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV). TPE rapidly removes ANCA IgG, complement and coagulation factors important in the pathogenesis of AAV. TPE has been used in patients with rapidly deteriorating renal function to achieve early disease control, allowing time for immunosuppressive agents to prevent resynthesis of ANCA. The PEXIVAS trial challenged the utility of TPE in AAV, as it did not show benefit of adjunctive TPE on a combined end point of end stage kidney disease (ESKD) and death.

AREAS COVERED

We analyze data from PEXIVAS and other trials of TPE in AAV, an up-to-date meta-analysis, and recently published large cohort studies.

EXPERT OPINION

There remains a role for the use of TPE in AAV in certain groups of patients, in particular those with severe renal involvement (Cr >500 μmol/L or dialysis-dependent). It should be considered in patients with Cr >300 μmol/L and rapidly deteriorating function, or with life-threatening pulmonary hemorrhage. A separate indication is patients double positive for anti-GBM antibodies and ANCA. TPE may have the greatest benefit as part of steroid-sparing immunosuppressive treatment strategies.

Circulating Calprotectin (cCLP) in autoimmune diseases

BACKGROUND AND AIM

Calprotectin (CLP) is a heterodimeric complex formed by two S100 proteins (S100A8/A9), which plays a pivotal role in innate immunity. Due to its intrinsic cytotoxic and proinflammatory properties, CLP controls cell differentiation, proliferation and NETosis and has been associated with a wide range of rheumatic diseases. Our review summarizes the widespread interest in circulating CLP (cCLP) as a biomarker of neutrophil-related inflammation, in autoimmune rheumatic disease (ARD) and non-ARD.

METHODS

A thorough literature review was performed using PubMed and EMBASE databases searching for circulating calprotectin and synonyms S100A8/A9, myeloid-related protein 8/14 (MRP8/MRP14), calgranulin A/B and L1 protein in addition to specific ARDs and autoimmune non-rheumatic diseases. We selected only English-language articles and excluded abstracts without the main text.

RESULTS

High cCLP serum levels are associated with worse structural outcomes in rheumatoid arthritis and to a lesser extent, in spondyloarthritis. In addition, cCLP can predict disease relapse in some autoimmune diseases including systemic lupus erythematosus (SLE), anti-neutrophil cytoplasmic antibodies-associated vasculitis (AAV) and some severe manifestations of connective tissue diseases, such as glomerulonephritis in SLE, AAV, juvenile idiopathic arthritis, adult-onset Still's disease and lung fibrosis in systemic sclerosis. Therefore, cCLP levels enable the identification of patients who need an accurate and tight follow-up. The clinical usefulness of cCLP as an inflammatory marker has been suggested for inflammatory/autoimmune non-rheumatic diseases, and especially for the monitoring of the inflammatory bowel diseases patients. Currently, there are only a few studies that evaluated the cCLP efficacy as a clinical biomarker in inflammatory/autoimmune non-rheumatic diseases with controversial results. Future studies are warranted to better clarify the role of cCLP in relation to the disease severity in myasthenia gravis, multiple sclerosis, chronic inflammatory demyelinating polyneuropathy, Graves' orbitopathy, autoimmune bullous diseases and uveitis.

CONCLUSION

Our literature review supports a relevant role of cCLP as potential prognostic biomarker mirroring local or systemic inflammation, especially in chronic inflammatory rheumatic diseases.

Clinical features and markers to identify pulmonary lesions caused by infection or vasculitis in AAV patients

OBJECTIVES

Pulmonary lesion is frequently seen in ANCA-associated vasculitis (AAV) patients primarily due to AAV lung involvement or infection, which are hard to differentiate due to their high similarity in clinical manifestations. We aimed to analyze the clinical features of pulmonary lesions consequent to AAV involvement or infection in AAV patients and further identify the markers for differential diagnosis.

METHODS

140 AAV patients who admitted to the Renmin Hospital of Wuhan University from January 2016 to July 2021 were included in this study. According to the nature of lung conditions, these patients were divided into the non-pulmonary lesion group, the lung infection group and the non-pulmonary infection group, and their demographics, clinical symptoms, imaging features, as well as laboratory findings were compared. A receiver operating characteristic (ROC) curve was drawn, and the diagnostic efficacy of single biomarker and composite biomarkers on pulmonary infection was then evaluated.

RESULTS

The patients in the lung infection group were significantly older than those in the no lesion group (63.19 ± 14.55 vs 54.82 ± 15.08, p = 0.022). Patients in the lung infection group presented more frequent symptoms and more obvious pulmonary image findings. Compared with patients in the non-pulmonary infection group, patients in the lung infection group showed a higher symptom incidence of fever, chest tightness, cough and expectoration, and hemoptysis (52.94% vs 16.00%, 61.76% vs 40.00%, 72.06% vs 46.00%, 27.94% vs 8.00%, p < 0.05, respectively), and more changes in pulmonary CT scanning images in terms of patched/striped compact opacity, alveolar hemorrhage, bronchiectasis, pleural effusion, as well as mediastinal lymphadenopathy (89.71% vs 52.00%, 11.76% vs 2.00%, 22.06% vs 8.00%, 50.00% vs 20.00%, 48.53% vs 24.00%, p < 0.05, respectively). In addition, patients in the lung infection group had significantly higher levels of serum pro-calcitonin (PCT), C-reactive protein (CRP), amyloid A (SAA), blood neutrophil-to-lymphocyte ratio (NLCR), erythrocyte sedimentation rate (ESR), as well as Birmingham vasculitis activity score (BVAS) than patients in the other two groups (p < 0.05). Among all biomarkers, PCT exhibited the highest diagnostic efficacy (0.928; 95%CI 0.89-0.97) for pulmonary infected AAV patients at a cut-off score of 0.235 ng/ml with 85.3% sensitivity and 84% specificity. Moreover, the composite biomarker of PCT-CRP-NLCR showed more diagnostic efficacy (0.979; 95% CI 0.95-1.00) in distinguishing the infectious and non-infectious lung injuries in AAV patients.

CONCLUSIONS

AAV patients with lung infection manifested more clinical symptoms and prominent lung image changes. The PCT and composite biomarker PCT-CRP-NLCR showed high diagnostic efficacy for a lung infection in AAV patients. Pulmonary lesion caused by either infection or AAV involvement is commonly seen and difficult to distinguish. We aim to identify the biomarkers that can be applied in the differentiation diagnosis of pulmonary lesions in AAV patients.

Metabolomics combined with clinical analysis explores metabolic changes and potential serum metabolite biomarkers of antineutrophil cytoplasmic antibody-associated vasculitis with renal impairment

Background

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is an autoimmune systemic disease, and the majority of AAV patients have renal involvement presenting as rapid progressive glomerulonephritis (GN). Currently, the clinically available AAV markers are limited, and some of the newly reported markers are still in the nascent stage. The particular mechanism of the level changes of various markers and their association with the pathogenesis of AAV are not well defined. With the help of metabolomics analysis, this study aims to explore metabolic changes in AAV patients with renal involvement and lay the foundation for the discovery of novel biomarkers for AAV-related kidney damage.

Methods

We performed liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based on serum samples from patients with AAV (N = 33) and healthy controls (N = 33) in order to characterize the serum metabolic profiling. The principal component analysis (PCA) and orthogonal partial least-squares-discriminant analysis (OPLS-DA) were used to identify the differential metabolites. Least Absolute Shrinkage and Selection Operator (LASSO) and eXtreme Gradient Boosting (XGBoost) analysis were further conducted to identify the potential diagnostic biomarker. A receiver operating characteristic (ROC) curve analysis was conducted to evaluate the diagnostic performance of the identified potential biomarker.

Results

A total of 455 metabolites were detected by LC-MS analysis. PCA and OPLS-DA demonstrated a significant difference between AAV patients with renal involvement and healthy controls, and 135 differentially expressed metabolites were selected, with 121 upregulated and 14 downregulated. Ninety-two metabolic pathways were annotated and enriched based on the KEGG database. N-acetyl-L-leucine, Acetyl-DL-Valine, 5-hydroxyindole-3-acetic acid, and the combination of 1-methylhistidine and Asp-phe could accurately distinguish AAV patients with renal involvement from healthy controls. And 1-methylhistidine was found to be significantly associated with the progression and prognosis of AAV with renal impairment. Amino acid metabolism exhibits significant alternations in AAV with renal involvement.

Conclusion

This study identified metabolomic differences between AAV patients with renal involvement and non-AAV individuals. Metabolites that could accurately distinguish patients with AAV renal impairment from healthy controls in this study, and metabolites that were significantly associated with disease progression and prognosis were screened out. Overall, this study provides information on changes in metabolites and metabolic pathways for future studies of AAV-related kidney damage and lays a foundation for the exploration of new biomarkers of AAV-related kidney damage.

Maintenance of Remission and Risk of Relapse in Myeloperoxidase-Positive ANCA-Associated Vasculitis with Kidney Involvement

BACKGROUND

The optimal strategy for remission-maintenance therapy in patients with myeloperoxidase-ANCA (MPO-ANCA)-associated vasculitis is not established. Defining parameters to guide maintenance therapy is required.

METHODS

This was a retrospective cohort study of all patients with MPO-ANCA-associated vasculitis (microscopic with polyangiitis and granulomatosis with polyangiitis) and GN followed at the Mayo Clinic between 1996 and 2015. Relapse rate, MPO-ANCA status, and remission-maintenance therapies were reviewed. Logistic regression models, Kaplan-Meier method, and Cox proportional hazards regression models were applied.

RESULTS

We analyzed 159 patients with active MPO-ANCA-associated vasculitis with GN. Sixty-six (42%) patients had at least one relapse, and 52 (33%) relapsed before 60 months. Patients with MPO-ANCA who became persistently negative did not relapse (hazard ratio [HR], 0.03; 95% confidence interval [95% CI], 0.002 to 0.431; P =0.01). The reappearance of MPO-ANCA was associated with a higher risk of relapse (HR, 1.91; 95% CI, 1.109 to 3.293; P =0.02). Immunosuppression was withdrawn in 80 (50%) patients, and this was less likely in those who received cyclophosphamide for remission induction or in patients with persistently positive MPO-ANCA (odds ratio [OR], 0.44; 95% CI, 0.228 to 0.861; P =0.02 and OR, 0.42; 95% CI, 0.213 to 0.820; P =0.01, respectively). Relapse frequency was not different between patients with persistently positive MPO-ANCA and patients with MPO-ANCA reappearance (44% versus 39%, P =0.49), irrespective of remission-maintenance treatment. Ear, nose, and throat involvement (OR, 6.10; 95% CI, 1.280 to 29.010; P =0.02) and MPO-ANCA reappearance (OR, 9.25; 95% CI, 3.126 to 27.361; P <0.001) were independently associated with relapse after treatment withdrawal.

CONCLUSIONS

Patients persistently MPO-ANCA negative are at low risk for relapse even without remission-maintenance therapy. Persistence or subsequent reappearance of MPO-ANCA is associated with a higher risk of relapse.

PODCAST

This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast.aspx?p=CJASN&e=2023_01_10_CJN06460622.mp3.

Old known and possible new biomarkers of ANCA-associated vasculitis

Antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV) comprises a group of multisystem disorders involving severe, systemic, small-vessel vasculitis with short- and long term serious and life-threating complications. Despite the simplification of treatment, fundamental aspects concerning assessment of its efficacy and its adaptation to encountered complications or to the relapsing/remitting/subclinical disease course remain still unknown. The pathogenesis of AAV is complex and unique, and despite the progress achieved in the last years, much has not to be learnt. Foremost, there is still no accurate marker enabling us to monitoring disease and guide therapy. Therefore, the disease management relays often on clinical judgment and follows a" trial and error approach". In the recent years, an increasing number of new molecules s have been explored and used for this purpose including genomics, B- and T-cell subpopulations, complement system factors, cytokines, metabolomics, biospectroscopy and components of our microbiome. The aim of this review is to discuss both the role of known historical and clinically established biomarkers of AAV, as well as to highlight potential new ones, which could be used for timely diagnosis and monitoring of this devastating disease, with the goal to improve the effectiveness and ameliorate the complications of its demanding therapy.

Eosinophile Granulomatose mit Polyangiitis – ein Übersichtsartikel

Die eosinophile Granulomatose mit Polyangiitis (EGPA) ist eine seltene Form der ANCA-assoziierten Vaskulitiden (AAV) aus der Gruppe der Kleingefäßvaskulitiden. Sie ist definiert als eine Vaskulitis kleiner und mittelgroßer Gefäße mit granulomatöser Entzündung sowie Blut- und Gewebseosinophilie. Fast alle Patienten haben allergische Symptome mit Asthma bronchiale und rhinosinusitischen Beschwerden. Das sonstige klinische Spektrum variiert je nach Lokalisation, Schweregrad und Art der Krankheitsmanifestation. Durch die eosinophile Infiltration und Inflammation kann es zu Rhinosinusitis, Pneumonitis, gastrointestinaler Beteiligung und Kardiomyopathie kommen. Insbesondere Letztere ist mit einer schlechteren Prognose assoziiert. Als nekrotisierende pauci-immune Kleingefäßvaskulitis kann die EGPA, ähnlich wie die anderen AAV, pulmonale Infiltrate mit alveolärer Hämorrhagie, eine Glomerulonephritis, kutane Vaskulitis mit Purpura, sowie zentrale und periphere neurologische Schädigungen verursachen. Das Auftreten perinukleärer ANCA (pANCA), mit Spezifität gegen die Myeloperoxidase (MPO) wird in etwa einem Drittel der Fälle beobachtet, ist allerdings nicht spezifisch für die EGPA. MPO-ANCA-positive Patienten haben häufiger eine periphere neurologische Beteiligung und eine Glomerulonephritis, während ANCA-negative Patienten häufiger eine kardiale und pulmonale Beteiligung aufweisen. Eine differentialdiagnostische Herausforderung im klinischen Alltag stellt die Abgrenzung zum hypereosinophilen Syndrom (HES) dar. Das Therapiekonzept der EGPA hängt davon ab, ob der Schweregrad der Erkrankung potentiell Organ- oder lebensbedrohlich ist. Bei schweren Formen der EGPA werden in der Akuttherapie hauptsächlich Glukokortikoide in Kombination mit Cyclophosphamid eingesetzt. Rituximab wird mittlerweile als alternative Behandlungsoption in den Leitlinien genannt. Zur Remissionserhaltung stehen verschiedene immunsuppressive Therapien zur Verfügung. Bei EGPA ohne schwere Organbeteiligung ist die IL-5 Blockade mit Mepolizumab zugelassen.

The effect of achieving serological remission on subsequent risk of relapse, end-stage renal disease and mortality in ANCA-associated vasculitis: a target trial emulation study

OBJECTIVE

To evaluate the effect of achieving a negative postinduction antineutrophil cytoplasmic antibody ANCA) assay on the risk of relapse, end-stage renal disease (ESRD) and death in ANCA-associated vasculitis (AAV).

METHODS

We emulated a target trial using observational data from the Mass General Brigham AAV cohort comparing patients who achieved versus did not achieve serological remission (negative ANCA assay) within 180 days of induction. Outcomes were relapse, ESRD or death within 5 years, obtained from medical records, the US Renal Data System and the National Death Index. We placed a 'clone' of each patient in both trial arms, censored those deviating from their assigned protocol and weighted each by the inverse probability of censoring. Outcomes were assessed by pooled logistic regression.

RESULTS

The study included 506 patients with AAV. The mean age was 61 years (SD 18) and the majority were women (58%), white (87%), myeloperoxidase-ANCA+ (72%) and had renal involvement (68%). Rituximab (59%) or cyclophosphamide (33%) was most often used for induction treatment. Within 5 years, 81 (16%) died, 51 (10%) had ESRD and 64 (13%) had relapse. Patients treated to a negative ANCA assay within 180 days had HR 0.55 (95% CI 0.38 to 0.81) for relapse and HR 0.87 (95% CI 0.61 to 1.25) for the composite of ESRD or death within 5 years.

CONCLUSIONS

In this emulated target trial from a large AAV cohort, achieving serological remission within 180 days of induction was associated with lower risk of relapse, but no statistically significant difference in ESRD or mortality outcomes.

Neutrophils in ANCA-associated vasculitis: Mechanisms and implications for management

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of systemic autoimmune diseases, which is typified by inflammatory necrosis predominantly affecting the small vessels and often accompanied by positive ANCA. Clinically, AAV primarily includes microscopic polyangiitis (MPA), granulomatosis with polyangiitis (GPA), and eosinophilic granulomatosis with polyangiitis (EGPA). It has been found that in AAV pathogenesis, both innate and adaptive immunity are related to neutrophil function mutually. Many proteins, such as myeloperoxidase (MPO) and proteinase 3 (PR3), in neutrophil cytoplasm lead to the production of proteins such as MPO-ANCA and PR3-ANCA by activating adaptive immunity. In addition, through the process of neutrophil extracellular trap (NET) formation, activation of an alternative complement pathway and the respiratory burst can stimulate the neutrophils close to vascular endothelial cells and will participate the vessel inflammation. This review aims to reveal the potential mechanisms regulating the association between the neutrophils and various types of AAVs and to emphasize the results of recent findings on these interactions. Moreover, multiple underlying signaling pathways involved in the regulation of neutrophils during AAV processes have also been discussed. The ultimate goal of this review is to identify novel biomarkers and therapeutic targets for AAV management in the future.

How best to manage relapse and remission in ANCA-associated vasculitis

INTRODUCTION

A 2-stage therapeutic approach is now applied as standard-of-care to treat ANCA-associated vasculitides (AAVs): first, glucocorticoids (GCs) combined with cyclophosphamide (CYC) or rituximab (RTX) to induce remission, then relapse prevention with remission-maintenance therapy. Nonetheless, a substantial risk of relapse persists.

AREAS COVERED

The authors provide an overview of the current state of maintenance therapies, and discuss new strategies recommended to prevent and treat relapses, focusing on granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA).

EXPERT OPINION

For remission-induction after GPA or MPA relapse with organ-threatening manifestations, reintroduction or intensification of the GC dose in combination with CYC or RTX cycle is recommended; we prefer RTX in light of its superior responses obtained in patients with relapsing disease. Rapid tapering of GCs has been shown not to alter AAV evolution while decreasing the risk of serious infections. In contrast, for non-severe, active MPA, we recommend GCs alone as first-line therapy. For patients whose MPA remains uncontrolled by GCs alone, immunosuppressant adjunction can be a GC-sparing option or to counter GC intolerance. Once remission is achieved, we recommend prolonged maintenance therapy with preemptive low-dose (500 mg) RTX infusion biannually.

Association between kinetic of Anti-Neutrophil Cytoplasmic Antibody (ANCA), renal survival and relapse risk in ANCA-glomerulonephritis

BACKGROUND

Anti-neutrophil cytoplasmic antibody (ANCA) kinetic in ANCA-associated vasculitis with glomerulonephritis (AAV-GN) has been suggested to be associated with AAV relapse. Few studies focused on its association with renal prognosis. Thus, we aimed to investigate the relationship between i) ANCA specificity and evolutive profile, and ii) renal outcomes.

METHODS

This multicentric retrospective study included patients diagnosed with ANCA-GN since 01/01/2000. Patients without ANCA at diagnosis and with fewer than 3 ANCA determinations during follow-up were excluded. We analyzed eGFR variation, renal-free and relapse-free survival according to three ANCA profiles (negative, recurrent, persistent) and to ANCA specificity (MPO or PR3).

RESULTS

Over a follow-up of 56 [34-101] months, a median of 19 [13-25] ANCA determinations were performed for the 134 included patients. Patients with a recurrent/persistent ANCA profile had a lower relapse-free (p = 0.019) survival and tended to have a lower renal survival (p = 0.053) compared to those with negative ANCA profile. Patients with a recurrent/persistent MPO-ANCA profile had the shortest renal survival (p = 0.015) and those with recurrent/persistent PR3-ANCA profile had the worst relapse-free survival (p = 0.013) compared to other profiles. The negative ANCA profile was associated with a greater eGFR recovery. In multivariate regression analysis, it was an independent predictor of a two-fold increase of eGFR at 2-year (OR = 6.79, 95% CI [1.78, 31.4], p = 0.008).

CONCLUSION

ANCA kinetic after ANCA-GN diagnosis is associated with outcomes. MPO-ANCA recurrence/persistence identifies patients with a lower potential of renal recovery and a higher risk of kidney failure, while PR3-ANCA recurrence/persistence identifies patients with a greater relapse risk. Thus, ANCA kinetic may help identify patients with a smoldering disease.

ANCA Associated Vasculitis (AAV): A Review for Internists

Anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) compromise a rare group of necrotizing small to medium vessel vasculitides that constitute three distinct disorders: granulomatosis with polyangiitis (GPA) (formerly known as Wegener's granulomatosis), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA) (formerly known as Churg-Strauss syndrome).AAV is characterized by the usual presence of circulating autoantibodies to the neutrophil proteins leukocyte proteinase 3 (PR3-ANCA) or myeloperoxidase (MPO-ANCA). These antibodies can activate neutrophils and the complement system resulting in vessel wall inflammation and damage.The clinical presentation of AAV varies from non-severe (non-life threatening) to severe often with potentially life-threatening multi-organ involvement. Early recognition and diagnosis are crucial. In the past two decades, advances in understanding the pathophysiology of AAV have led to development of new treatments and resulted in significant improvement in general outcomes and survival rates.This narrative review will focus on GPA and MPA. We will highlight clinical manifestations, diagnosis, disease monitoring, and treatment strategies in patients with AAV.

Do Relapses Follow ANCA Rises? A Systematic Review and Meta-Analysis on the Value of Serial ANCA Level Evaluation

Objectives

ANCA-vasculitis (AAV) patients frequently suffer from relapses and risk subsequent organ damage. There is much debate on the value of serial ANCA level evaluation to monitor disease activity. We aimed to evaluate the association between ANCA rises and disease relapses at (I) moment of the rise, (II) within 6 months or (III) within a year from the rise.

Methods

3 databases (MEDLINE, EMBASE, COCHRANE) were searched from 1993 through September 2021. We included studies that reported relapse incidence within 12 months after an ANCA rise measured by antigen-specific immunoassays in peripheral blood of AAV patients in remission. Quality assessment was performed using QUADAS-2. Finally, a meta-analysis was carried out to estimate average OR using a random effects model.

Results

Twenty unique studies were included. The methodological quality was limited due to risk of selection bias. An ANCA rise often preceded a disease relapse within 6 months (OR 3.65, 95% CI 1.66–8.03) and less often within 12 months (OR 2.88, 95% CI 1.21–6.88), while it was not indicative of a concurrent relapse (OR 0.13, 95% CI 0.03–0.53). Once a relapse is diagnosed, ANCA is significantly more often present than not (OR 10.80, 95% CI 3.82–30.55). As expected based on clinical, technical and methodological variability between studies, there was substantial heterogeneity across studies in all analyses (I2 = 70–87%).

Conclusion

In previously ANCA-positive patients, the ANCA test is often positive upon clinical suspicion of a disease relapse. Patients with a rise in ANCA are at risk of encountering disease relapses in the upcoming 6 or 12 months.

Profile of circulating extracellular vesicles microRNA correlates with the disease activity in granulomatosis with polyangiitis

Granulomatosis with polyangiitis is a chronic systemic inflammation of small vessels characterized by circulating anti-proteinase 3 antibodies. MicroRNAs are short transcripts specifically inhibiting protein translation. Neutrophils can release extracellular vesicles (EVs). In this study, we characterized profile of microRNA trafficked by EVs in GPA. Fifty patients with GPA were enrolled in the study, 25 at acute phase and 25 in remission. EVs were isolated from the blood serum, characterized by their number, size distribution. Following unbiased screening for microRNA expression, differentially expressed candidates were measured by quantitative real-time PCR. Circulating DNA-myeloperoxidase complexes and apoptosis-related transcripts in peripheral blood neutrophils were quantified. We identified four differentially expressed microRNAs from EVs in granulomatosis with polyangiitis (GPA). MirRs-223-3p, 664a-3p, and 200b-3p were overexpressed and miR-769-5p suppressed in the disease. A distinction between GPA and healthy controls was the best for miR-223-3p, whereas miR-664a-3p discriminated between active vs. remission of GPA. Correct classification of the disease based on multivariate discriminant analysis was between 92% for acute phase and 85% for all study participants. Bioinformatics tools identified genes transcripts potentially targeted by the microRNAs belonging to pathways of focal adhesion, mTOR signaling and neutrophil extracellular traps formation. Two microRNAs positively correlating with the disease activity were involved in neutrophil extracellular traps formation and apoptosis inhibition. A comprehensive characteristics of microRNAs trafficked in bloodstream inside EVs correlates well with our understanding of the mechanisms of GPA and suggests the importance of EVs in progression of the disease.

Utility of interval kidney biopsy in ANCA-associated vasculitis

OBJECTIVES

ANCA-associated vasculitis (AAV) is a rare autoimmune disorder that commonly involves the kidney. Early identification of kidney involvement, assessing treatment-response and predicting outcome are important clinical challenges. Here, we assessed the potential utility of interval kidney biopsy in AAV.

METHODS

In a tertiary referral centre with a dedicated vasculitis service, we identified patients with AAV who had undergone interval kidney biopsy, defined as a repeat kidney biopsy (following an initial biopsy showing active AAV) undertaken to determine the histological response in the kidney following induction immunosuppression. We analysed biochemical, histological and outcome data, including times to kidney failure and death for all patients.

RESULTS

We identified 57 patients with AAV who underwent at least one interval kidney biopsy (59 interval biopsies in total; median time to interval biopsy ∼130 days). Of the 59 interval biopsies performed, 24 (41%) patients had clinically suspected active disease at time of biopsy which was confirmed histologically in only 42% of cases; 35 (59%) patients were in clinical disease-remission, and this was correct in 97% of cases. The clinician's impression was incorrect in one in four patients. Hematuria at interval biopsy did not correlate with histological activity. Interval biopsy showed fewer acute lesions and more chronic damage compared with initial biopsy and led to immunosuppressive treatment-change in 75% (44/59) of patients. Clinical risk prediction tools tended to operate better using interval biopsy data.

CONCLUSION

Interval kidney biopsy is useful for determining treatment-response and subsequent disease management in AAV. It may provide better prognostic information than initial kidney biopsy and should be considered for inclusion into future clinical trials and treatment protocols for patients with AAV.

Is There Still a Role of Plasma Exchange in the Current Management of ANCA-Associated Vasculitides?

Purpose of Review

Plasma exchange (PLEX) is often recommended as an adjunctive therapy for patients with ANCA-associated vasculitis (AAV) in the setting of rapidly progressive glomerulonephritis or diffuse alveolar haemorrhage. Since ANCAs are pathogenic, it seems a reasonable and justified approach to remove them through therapeutic PLEX, as despite advances in immunosuppressive therapy regimens, AAV is associated with significant morbidity and death. However, the association between ANCA levels and mortality or disease activity is uncertain. In addition, any treatment must be judged on the potential risks and benefits of its use. Here, we summarise the current data on PLEX usage in patients with AAV.

Recent Findings

The largest randomised trial to date the Plasma Exchange and Glucocorticoids in Severe ANCA-Associated Vasculitis (PEXIVAS) study failed to show added benefit for PLEX on the prevention of death or end-stage renal failure (ESRF) for the management of patients with severe AAV. However, there is a possibility that PLEX delays dialysis dependence and ESRF in the early stages of the disease. Regardless of whether this is only for 3 to 12 months, this could be of clinical significance and a substantial improvement in patient’s quality of life.

Summary

Cost utility analysis and trials including patient-centred outcomes are required to evaluate the use of PLEX. Furthermore, ascertaining those at high risk of developing ESRF could help identify those who may benefit from PLEX the most, and further insights are required in setting of diffuse alveolar haemorrhage.

Psychometric properties of outcome measurement instruments for ANCA-associated vasculitis: a systematic literature review

OBJECTIVES

To systematically review the psychometric properties of outcome measurement instruments used in ANCA-associated vasculitis (AAV).

METHODS

Medline, EMBASE, Cochrane, Scopus and Web of Science were searched from inception to 14 July 2020 for validation studies of instruments used in AAV. Following the COnsensus-based Standards for the selection of health status Measurement INstruments (COSMIN) and OMERACT frameworks, different psychometric properties (validity, reliability, responsiveness and feasibility) were summarized. Risk of bias was assessed according to the COSMIN checklist.

RESULTS

From 2505 articles identified, 32 met the predefined selection criteria, providing information on 22 instruments assessing disease activity (n = 7), damage (n = 2), activity and damage (n = 1), health-related quality of life (HRQoL; n = 9) and function (n = 3). Most of the instruments were tested in AAV as a group or in granulomatosis with polyangiitis only.The BVAS, any version, the Vasculitis Damage Index (VDI) and the AAV-Patient-Reported Outcome (AAV-PRO) have been more extensively validated than the other instruments. BVAS for Wegener Granulomatosis (BVAS/WG) has been shown to be valid for measuring disease activity [correlation with Physician global assessment (r = 0.90)], reliability (inter-observer intraclass correlation coefficient = 0.97), responsiveness and feasibility. For damage, VDI was shown to be moderately valid (correlations with BVAS version 3 at 6 months r = 0.14, BVAS/WG at 1 year r = 0.40 and 5 years r = 0.20), and feasible. For HRQoL, AAV-PRO demonstrated validity (correlations of the six AAV-PRO domains with EQ-5D-5L: -0.78 to -0.55; discrimination between active disease and remission, P < 0.0001 for all comparisons). The overall performance of instruments assessing function was low-to-moderate.

CONCLUSION

Among the 22 outcome measurement instruments used for AAV, BVAS (any version), VDI and AAV-PRO had the strongest psychometric properties.

A glance into the future of anti-neutrophil cytoplasmic antibody-associated vasculitis

In the past decade, unprecedented progress has been made in understanding the pathogenesis, diagnosis, assessment, and treatment of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs). International collaborations and input from several fields (e.g. immunology, rheumatology, and nephrology) have been critical for analyzing demographics, disease manifestations, and outcomes in clinical research studies. Such efforts opened new avenues for generating novel questions and rationale to design better clinical trials. In addition, clinical research has been a source of several biological discoveries and the starting point for knowledge seeking on the pathophysiology of AAV. Interestingly, the blending of clinical and basic research provides a platform for personalized medicine. Despite recent revisions on AAV classification, the incorporation of new findings on disease genetics and immunologic responses may soon result in changes in clinical practice. These advances will enhance the selection of more specific and targeted therapies. However, current unmet needs in the management of AAV are still sizable and heavily impact long-term survival. Especially, frequent relapses, damage accrual, and high morbidity contribute to poor outcomes. Finally, the lack of defined biomarkers for disease activity and the prognosis is a permanent challenge in AAV research. Our work provides an overview of the current state of the art in AAV literature and suggests bridges for the remaining knowledge gaps. It offers potential future directions for the clinical assessment, management, and research in the field toward a more personalized medicine approach.

Pathogenesis-based new perspectives of management of ANCA-associated vasculitis

While the pathogenesis of anti-neutrophil cytoplasmic autoantibody associated vasculitis (AAV) is still not fully elucidated, there is a mounting evidence that it is initiated by inflammation and activation of innate immunity in the presence of predisposing factors, innate immunity, aberrant responses of the adaptive immune system, and complement system activation. Biologics targeting inflammation-related molecules in the immune system have been explored to treat AVV, and these treatments have provided revolutionary advances. When focusing on the pathogenic mechanisms of AVV, this review presents the new findings regarding novel therapeutic approaches for the management of these conditions.

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.

Predicting relapse in anti-neutrophil cytoplasmic antibody-associated vasculitis: a Systematic review and meta-analysis

Objectives

Relapses affect 30–50% of patients with ANCA-associated vasculitis (AAV) over 5 years, necessitating long-term treatment. Although there have been studies looking at predictors of relapse in AAV, this research has yet to translate clinically into guidance on tailored therapy. The aim of this systematic review was to identify and meta-analyse existing risk factors from the literature and produce a model to calculate individualised patient risk of relapse.

Method

A search strategy was developed to include all studies identifying predictors of AAV relapse using multivariate analysis. Individual risk factors were extracted and pooled hazard ratios (HRs) calculated. A model to predict the time to first relapse based on identified risk factors was tested retrospectively using a cohort of patients with AAV.

Results

The review of 2674 abstracts identified 117 papers for full text review, with 16 eligible for inclusion. Pooled HRs were calculated from significant risk factors, including anti-PR3 ANCA positivity [HR 1.69 (95% CI 1.46, 1.94)], cardiovascular involvement [HR 1.78 (95% CI 1.26, 2.53)], creatinine >200 µmol/l (relative to creatinine ≤100) [HR 0.39 (95% CI 0.22, 0.69)] and creatinine 101–200 µmol/l [HR 0.81 (95% CI 0.77, 0.85)]. Using data from 182 AAV patients to validate the model gave a C-statistic of 0.61.

Conclusion

Anti-PR3 ANCA positivity, lower serum creatinine and cardiovascular system involvement are all associated with an increased risk of relapse, and a combination of these risk factors can be used to predict the individualised risk of relapse. In order to produce a clinically useful model to stratify risk, we need to identify more risk factors, with a focus on robust biomarkers.

ANCA status and renal parameters at month 12 post-diagnosis can help predict subsequent relapses in patients with granulomatosis with polyangiitis

OBJECTIVE

To determine the predictive value of disease characteristics at 12-month follow-up after the diagnosis of GPA for subsequent relapses in a cohort of patients followed at a tertiary vasculitis clinic.

METHODS

Demographic, clinical, and biological data at diagnosis and during follow-up from patients with GPA followed for at least 24 months at the Mount Sinai Hospital Vasculitis Clinic in Toronto, Canada were extracted from the Canadian Vasculitis Research Network (CanVasc) database and analyzed. The association between ANCA status and type (PR3- or MPO-ANCA), presence of microscopic hematuria, or serum creatinine level at follow-up month 12 ± 3 (M12) and relapses after M12 were assessed using Cox proportional hazard models.

RESULTS

A total of 113 GPA patients were included in this study (50 ANCA positive, 63 ANCA negative at M12). Patient demographics and disease characteristics were similar at diagnosis, including the treatments used for induction and at M12. The global 5-year relapse rate was 55.8%, without any difference in the relapse rates after M12 between those ANCA-positive or negative at M12. However, in multivariate analyses, MPO-ANCA positivity at M12 was predictive of increased relapses after M12 (hazard ratio [HR] 3.54, P=0.01), as was the presence of microhematuria at M12 (HR 1.91, P=0.04). In contrast, higher serum creatinine levels at M12 were associated with a decreased risk of subsequent relapse (HR 0.99, P=0.04).

CONCLUSION

In this cohort of patients with GPA, MPO-ANCA positivity and persistent microscopic hematuria at M12 were associated with increased risk of subsequent relapse, and could thus have value to predict disease outcome during follow-up.

Anti-Neutrophil Cytoplasmic Antibodies: To Care or Not to Care

Anti-neutrophil cytoplasmic antibodies (ANCA) associated vasculitis is a disease process with a wide range of presentations, from asymptomatic or minimally symptomatic disease with positive laboratory testing, to florid acute end-organ damage. Consensus has not been established as to the frequency and/or protocol by which ANCA testing should be repeated. We present the case of a 53-year-old woman who initially came to medical attention with persistent dyspnea and pulmonary infiltrates presumed to be due to acute exacerbation of chronic diastolic congestive heart failure. Extensive infectious disease testing was negative, but ANCA testing was positive. However, because antinuclear antibody (ANA) interference in the original sample rendered the test result difficult to interpret, the test was not repeated. The patient presented eight months after the initial hospitalization with acute hypoxemic respiratory failure requiring intubation, with an ANCA titer of 1:1280 with a negative ANA titer, and renal biopsy-proven severe crescentic glomerulonephritis. In the discussion of our case, we review the importance of interpreting ANCA testing in the correct clinical context. The ANCA laboratory testing requires cautious interpretation, and diagnosed ANCA-associated vasculitis (AAV) requires vigilance for prompt and proactive treatment.

Indications and diagnostic outcome of antineutrophil cytoplasmic antibody testing in hospital medicine: a pattern of over-screening

INTRODUCTION/OBJECTIVE

Antineutrophil cytoplasmic antibodies (ANCA) serology can aid in the diagnosis and classification of ANCA-associated vasculitides (AAV). However, it is often ordered in patients without clinical manifestations of vasculitis. In this retrospective chart review, we aim to better understand the clinical practices on ANCA testing.

METHODS

We retrospectively reviewed patients' charts for the indications and diagnostic outcomes of ANCA tests. All ANCA tests ordered at two Canadian hospitals (a community hospital and an academic tertiary hospital) between January and December 2016 were included in the study. Descriptive statistics are used.

RESULTS

A total of 302 ANCA tests were included. The majority (n = 198, 65.6%) were ordered without an indication for testing. For those patients with at least 1 clinical manifestation of AAV (n = 104), 25% were ANCA positive and 18.3% resulted in a diagnosis of AAV. In comparison, among those without a clinical manifestation of AAV (n = 198), only 1.5% were ANCA positive and none was diagnosed with AAV. All patients diagnosed with AAV had at least 1 indication for ANCA testing. The three most common clinical presentations in patients with a final diagnosis of AAV were glomerulonephritis (81.8%), pulmonary hemorrhage (45.5%), and multiple lung nodules (31.8%).

CONCLUSION

To our knowledge, this is the first study that evaluates patients with both positive and negative ANCA test results in an inpatient setting. We demonstrated a low rate of ANCA positivity and AAV diagnosis in patients without clinical manifestations of AAV. Overall, there is a high rate of ANCA testing without an indication at our academic institution. This over-testing may be curbed by strategies such as a gating policy, culture changes, and clinician education. Key Points • AAV is a clinical-pathological diagnosis, and despite the usefulness of ANCA testing, it does not confirm nor rule out AAV. • ANCA testing for the diagnosis of AAV is generally only indicated when there is a clear manifestation of AAV. • Although patients with AAV may occasionally present without classic signs and symptoms, the diagnostic utility of ANCA serology in this setting is low, and testing is more likely to result in a false-positive or false-negative test. • If clinical suspicion remains high despite negative ANCA testing, clinicians should seek consultation with a rheumatologist.

2021 American College of Rheumatology/Vasculitis Foundation Guideline for the Management of Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

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.

2021 American College of Rheumatology/Vasculitis Foundation Guideline for the Management of Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

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.

New therapeutic strategies in lung vasculitis

PURPOSE OF REVIEW

To summarize the latest publications and provide a practical overview of treatment strategies for lung vasculitis associated with antineutrophil cytoplasmic antibodies (ANCAs).

RECENT FINDINGS

In patients with severe ANCA-associated vasculitis, plasma exchange, as adjunctive therapy to standard treatment, is not associated with improved survival or reduced risk of end-stage kidney disease. A regimen with reduced dose of glucocorticoids is equally effective to induce remission as a standard regimen. In patients without organ or life-threatening disease, mycophenolate mofetil can be used in combination with oral glucocorticoid therapy to induce remission, however, with a higher risk of relapse than when using rituximab or cyclophosphamide. For maintenance of remission, a tailored regimen of rituximab infusion was equivalent to a fixed regimen, with fewer perfusions. Belimumab, a human IgG1(Equation is included in full-text article.)monoclonal antibody against B-lymphocyte stimulator, did not decrease the relapse rate when added to azathioprine and glucocorticoids. Avacopan, a complement C5a receptor inhibitor, was effective in replacing high-dose glucocorticoids in achieving complete remission of vasculitis.

SUMMARY

Significant advances have been made in the treatment strategy to both induce remission and maintain remission in patients with ANCA-associated vasculitis. The choice should take into consideration efficacy, cost-effectiveness, safety profile, ease of use, and possibility of individual tailoring of treatment.