Relapse in Anti-Neutrophil Cytoplasm Antibody (ANCA)-Associated Vasculitis

Neutrophil single-cell analysis identifies a type II interferon-related subset for predicting relapse of autoimmune small vessel vasculitis

To identify the dynamics of neutrophil autoimmunity, here we focus on anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis and perform single-cell transcriptome and surface proteome analyses on peripheral white blood cells from patients with new-onset microscopic polyangiitis (MPA). Compared with controls, two neutrophil populations, immature neutrophils and neutrophils with type II interferon signature genes (Neu_T2ISG), are increased in patients with MPA. Trajectory and cell-cell interaction analyses identify Neu_T2ISG as a subset that differentiates from mature neutrophils upon stimulation with IFN-γ and TNF, which synergize to induce myeloperoxidase and Fcγ receptors expression on the neutrophil cell surface and promote ANCA-induced neutrophil extracellular trap formation. Case-by-case analysis indicates that patients with a high proportion of the Neu_T2ISG subset are associated with persistent vasculitis symptoms. A larger cohort analysis shows that serum IFN-γ levels at disease onset correlate with susceptibility to disease relapse. Our findings thus identify neutrophil diversity at the single cell level and implicate a biomarker for predicting relapse in small vessel vasculitis.

Relapses and serious adverse events during rituximab maintenance therapy in ANCA-associated vasculitis: a multicentre retrospective study

OBJECTIVES

There are limited real-life data regarding the efficacy and safety of rituximab (RTX) as a remission maintenance agent in microscopic polyangiitis (MPA) and granulomatosis-with-polyangiitis (GPA). We aimed to estimate the incidence and risk factors for relapses, as well for serious adverse events (SAEs) in MPA/GPA patients during RTX maintenance.

METHODS

A retrospective cohort of newly diagnosed/relapsing GPA/MPA patients who received RTX maintenance (≥1 RTX cycle, ≥6 months follow-up) following complete remission (BVAS version-3 = 0 plus prednisolone ≤7.5 mg/day) with induction regimens. SAEs included serious infections, COronaVIrus-Disease 2019 (COVID-19)-associated hospitalizations, deaths, cardiovascular events, malignancies and hypogammaglobulinemia. The incidence rates (IRs) and relapse-free survival were estimated through Kaplan-Meier plots. Cox regression was conducted to investigate factors associated with the time-to-relapse.

RESULTS

A total of 101 patients were included: 48% females, 69% GPA, 53% newly diagnosed, median age 63 years. During follow-up (294.5 patient-years, median: 3 RTX cycles), 30 relapses (57% major) occurred among 24 patients (24%, IR 10.2/100 patient-years). Kidney involvement (adjusted hazard ratio/aHR: 0.20; 95% CI: 0.06-0.74, P = 0.016), prior induction with RTX plus CYC (vs RTX monotherapy: aHR = 0.02; 95% CI: 0.001-0.43, P = 0.012) and shorter time interval until complete remission (aHR = 1.07; 95% CI: 1.01-1.14, P = 0.023) were associated with decreased relapse risk. We recorded 17 serious infections (IR 5.8/100 patient-years), 11 COVID-19-associated hospitalizations (IR 3.7/100 patient-years), 4 malignancies (IR 1.4/100 patient-years), 6 cardiovascular events (IR 2/100 patient-years) and 10 deaths (IR 3.4/100 patient-years).

CONCLUSION

In this real-world study, relapses during RTX maintenance occurred in approximately 1 out of 4 patients. Kidney involvement, induction with RTX plus CYC, and earlier achievement of complete remission were associated with lower relapse risk. The serious infections rate was consistent with previous reports, whereas an increased rate of COVID-19-associated hospitalizations was observed.

Effectiveness and safety of rituximab in severely relapsed antineutrophil cytoplasmic antibody-associated vasculitis: a retrospective analysis of a Japanese multicentre cohort from the J-CANVAS

We aimed to clarify the long-term safety and efficacy of rituximab (RTX) as a remission induction therapy following severe relapse in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). We retrospectively collected the data of patients with severely relapsed AAV from a Japanese multicentre cohort. The primary exposure was RTX use; the primary outcome was complete remission (CR) proportions at week 24. Baseline characteristics were compared between the RTX and non-RTX groups. We performed multivariate logistic regression analysis and one-to-one propensity score matching analysis as a sensitivity analysis. Totally, 100 patients were enrolled: 52 in the RTX group and 48 in the non-RTX group. Baseline characteristics were comparable between the two groups, except for age, AAV subtype and ANCA serotype. The median age was 71 vs. 75 years, and the PR3-ANCA positivity rate was 44.2% vs. 18.8% in the RTX and non-RTX groups, respectively. No significant difference was observed in CR proportions at week 24 between the two groups (79.2% vs. 68.1%, p = 0.321), with an adjusted odds ratio of 1.27 (95% confidence interval [CI] 0.47-3.51). At week 48, CR proportions were significantly higher in the RTX group (91.7% vs. 64.9%, p = 0.005), with an adjusted odds ratio of 2.95 (95% CI 0.97-9.91). Serious infection rates were lower in the RTX group than in the non-RTX group, with no statistically significant difference. RTX was not superior to conventional immunosuppressive therapies at week 24 but showed significantly favourable results at week 48 for severely relapsed AAV.

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.

Rituximab as maintenance therapy for ANCA-associated vasculitides: pooled analysis and long-term outcome of 277 patients included in the MAINRITSAN trials

OBJECTIVE

To compare the long-term efficacy and safety of azathioprine (AZA), 18-month fixed-schedule rituximab (RTX), 18-month tailored RTX and 36-month RTX in preventing relapses in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis who achieved a complete remission after induction therapy. Patients treated with 36-month RTX received either a fixed or a tailored regimen for the first 18 months and a fixed regimen for the last 18 months (36-month fixed/fixed RTX and 36-month tailored/fixed RTX, respectively).

METHODS

The Maintenance of Remission using Rituximab in Systemic ANCA-associated Vasculitis (MAINRITSAN) trials sequentially compared: 18-month fixed-schedule RTX versus AZA (MAINRITSAN); 18-month fixed-schedule RTX versus 18-month tailored-RTX (MAINRITSAN2); and extended therapy to 36 months with four additional RTX infusions after MAINRITSAN2 versus placebo (MAINRITSAN3). Patients were then followed prospectively through month 84 and their data were pooled to analyse relapses and adverse events. The primary endpoint was relapse-free survival at month 84.

RESULTS

277 patients were enrolled and divided in 5 groups: AZA (n=58), 18-month fixed-schedule RTX (n=97), 18-month tailored-RTX (n=40), 36-month tailored/fixed RTX (n=42), 36-month fixed/fixed RTX (n=41). After adjustment for prognostic factors, 18-month fixed-schedule RTX was superior to AZA in preventing major relapses at month 84 (HR 0.38, 95% CI 0.20 to 0.71). The 18-month tailored-RTX regimen was associated with an increased risk of major relapse compared with fixed-schedule regimen (HR 2.92, 95% CI 1.43 to 5.96). The risk of major relapse was similar between 36-month fixed/fixed and 18-month fixed-RTX (HR 0.69, 95% CI 0.38 to 1.25).

CONCLUSIONS

According to these results, it appears that the 84-month remission rate is higher with an 18-month fixed RTX regimen compared with AZA and 18-month tailored RTX. Also, extending RTX to 36 months does not appear to reduce the long-term relapse rate compared with the 18-month fixed RTX regimen. However, as this study was underpowered to make this comparison, further prospective studies are needed to determine the potential long-term benefits of extending treatment in these patients.

ANCA-Associated Vasculitis: Practical Issues in Management

ANCA associated vasculitides are multi-system autoimmune diseases which are increasing in prevalence. In this review we will discuss the clinical manifestations and review the management options. We highlight the various trials of induction and maintenance therapy and discuss the areas of unmet need. These include understanding which patients are at highest risk of relapse, clinical adaptation of improved biomarkers of disease activity and tools to discuss long term prognosis.

Time to normalisation of C-reactive protein and incidence of relapse in microscopic polyangiitis: A medical records review study in Japan

OBJECTIVES

Despite the identification of risk factors for relapses in antineutrophil cytoplasmic antibody-associated vasculitis, the relationship between changes in C-reactive protein (CRP) levels after the initial treatment and the incidence of relapse remains unknown. This study aimed to assess the association between the time taken for normalisation of CRP levels and the incidence of relapse in Japanese adult patients with microscopic polyangiitis.

METHODS

This study included 85 consecutive patients with newly diagnosed microscopic polyangiitis who achieved remission after 6 months of immunosuppressive treatment at the Aichi Medical University Hospital between 2009 and 2017. The relationship between the time to normalisation of CRP after the initial immunosuppressive treatment and relapse incidences was evaluated using multivariable Cox proportional hazard models.

RESULTS

During the follow-up period, 13 (30.2%), 7 (41.2%), and 16 (64.0%) patients relapsed (P = .025) within 1-14, 15-28, and ≥29 days of normalisation, respectively. The hazard ratios [95% confidence intervals (CIs)] for the time to normalisation of CRP of 1-14, 15-28, and ≥29 days were 1.00 (reference), 2.42 (95% CI: 0.92-6.39), and 3.48 (95% CI: 1.56-7.76), respectively.

CONCLUSIONS

A significant association between the time to normalisation of CRP and the relapse incidence in Japanese patients with microscopic polyangiitis was observed.

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.

Rituximab for the Treatment of Anti-glomerular Basement Membrane Disease with Isolated Diffuse Alveolar Hemorrhage

Anti-glomerular basement membrane (GBM) disease with isolated diffuse alveolar hemorrhage (DAH) is rare. We herein report a 91-year-old man admitted with hypoxia and diagnosed with anti-GBM disease with DAH based on positive bronchoalveolar lavage and serum antibody test results. There was no renal involvement. Although remission was achieved using glucocorticoids and plasmapheresis, the patient experienced DAH relapse one week after the last plasmapheresis. Rituximab 375 mg/m2 was administered 4 times weekly; thereafter, DAH relapse was not observed, and the glucocorticoid dosage was tapered. Rituximab was thus effective in treating anti-GBM disease with isolated DAH in an extremely elderly patient.

Management of antineutrophil cytoplasmic antibody-associated vasculitis: a review of recent guidelines

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is an autoimmune rheumatic disease consisting of three discrete diagnoses of microscopic polyangiitis, granulomatosis with polyangiitis, and eosinophilic granulomatosis with polyangiitis. Among diseases treated in a rheumatology department, AAV has poor clinical outcomes, with high rates of mortality and progression to end-stage renal disease and frequent disease relapse. Due to the frequent negative patient outcomes, optimal therapeutic strategies are essential in the management of AAV. In the present review, four guidelines for management of AAV are summarized: British Society for Rheumatology (BSR) and British Health Professionals in Rheumatology (BHPR) guideline for the management of adults with AAV; European League Against Rheumatism (EULAR)/European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) recommendation for the management of AAV; 2021 American College of Rheumatology (ACR)/Vasculitis Foundation Guideline for the Management of AAV; Kidney Disease: Improving Global Outcome (KDIGO) 2021 Clinical Practice Guideline for the Management of Glomerular Diseases, which will aid in clinicians' medical decisions. Finally, the summary of the 2022 Update of the EULAR Recommendations on the Management of AAV, presented in the EULAR Congress 2022 is also introduced.

Steroid sparing in vasculitis: Myth or reality?

Glucocorticoids are the cornerstone of therapy for all forms of vasculitis. However, glucocorticoid treatment carries with it the risk of glucocorticoid toxicity. Recent research efforts in vasculitis have emphasized investigation into strategies that reduce glucocorticoid exposure. These strategies include the adoption of rapid-acting steroid-sparing agents, reduced-dose glucocorticoid induction regimens, the early introduction of steroid-sparing agents for maintenance therapy, and the extension of maintenance therapy to minimize glucocorticoid exposure associated with disease relapse. These are critical advances to move us toward the goal of glucocorticoid-free treatment of vasculitis. The evidence supporting each of these strategies and directions for future research are explored.

Association of baseline soluble immune checkpoints with the risk of relapse in PR3-ANCA vasculitis following induction of remission

OBJECTIVES

We investigated whether soluble immune checkpoints (sICPs) predict treatment resistance, relapse and infections in patients with antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV).

METHODS

Plasma sICP concentrations from available samples obtained during conduct of the RAVE trial were measured by immunoabsorbent assays from patients with either proteinase 3 (PR3) or myeloperoxidase (MPO)-ANCA vasculitis and were correlated with clinical outcomes, a set of biomarkers and available flow cytometry analyses focusing on T cell subsets. Log-rank test was used to evaluate survival benefits, and optimal cut-off values of the marker molecules were calculated using Yeldons J.

RESULTS

Analysis of 189 plasma samples at baseline revealed higher concentrations of sTim-3, sCD27, sLag-3, sPD-1 and sPD-L2 in patients with MPO-ANCA vasculitis (n=62) as compared with PR3-ANCA vasculitis (n=127). Among patients receiving rituximab induction therapy (n=95), the combination of lower soluble (s)Lag-3 (<90 pg/mL) and higher sCD27 (>3000 pg/mL) predicted therapy failure. Twenty-four out of 73 patients (32.9%) in the rituximab arm reaching remission at 6 months relapsed during follow-up. In this subgroup, high baseline values of sTim-3 (>1200 pg/mL), sCD27 (>1250 pg/mL) and sBTLA (>1000 pg/mL) were associated with both sustained remission and infectious complications. These findings could not be replicated in 94 patients randomised to receive cyclophosphamide/azathioprine.

CONCLUSIONS

Patients with AAV treated with rituximab achieved remission less frequently when concentrations of sLag-3 were low and concentrations of sCD27 were high. Higher concentrations of sTim-3, sCD27 and sBTLA at baseline predicted relapse in patients treated with rituximab. These results require confirmation but may contribute to a personalised treatment approach of AAV.

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.

The neutrophil: A key resourceful agent in immune‐mediated vasculitis

The term "vasculitis" refers to a group of rare immune-mediated diseases characterized by the dysregulated immune system attacking blood vessels located in any organ of the body, including the skin, lungs, and kidneys. Vasculitides are classified according to the size of the vessel that is affected. Although this observation is not specific to small-, medium-, or large-vessel vasculitides, patients show a high circulating neutrophil-to-lymphocyte ratio, suggesting the direct or indirect involvement of neutrophils in these diseases. As first responders to infection or inflammation, neutrophils release cytotoxic mediators, including reactive oxygen species, proteases, and neutrophil extracellular traps. If not controlled, this dangerous arsenal can injure the vascular system, which acts as the main transport route for neutrophils, thereby amplifying the initial inflammatory stimulus and the recruitment of immune cells. This review highlights the ability of neutrophils to "set the tone" for immune cells and other cells in the vessel wall. Considering both their long-established and newly described roles, we extend their functions far beyond their direct host-damaging potential. We also review the roles of neutrophils in various types of primary vasculitis, including immune complex vasculitis, anti-neutrophil cytoplasmic antibody-associated vasculitis, polyarteritis nodosa, Kawasaki disease, giant cell arteritis, Takayasu arteritis, and Behçet's disease.

The frequency of Treg subsets distinguishes disease activity in ANCA vasculitis

Objectives

T regulatory cells (Tregs) are a heterogeneous group of immunoregulatory cells that dampen self-harming immune responses and prevent the development of autoimmune diseases. In anti-neutrophil cytoplasmic autoantibody (ANCA) vasculitis, Tregs possess diminished suppressive capacity, which has been attributed to the expression of a FOXP3 splice-variant lacking exon 2 in T cells (FOXP3Δ2 CD4+ T cells). However, the suppressive capacity of Tregs varies between subsets. We evaluated the frequency of Treg subsets in ANCA vasculitis as a potential explanation for diminished suppressive capacity.

Methods

We developed a custom mass cytometry panel and performed deep immune profiling of Tregs in healthy controls, patients with active disease and in remission. Using these data, we performed multidimensional reduction and discriminant analysis to identify associations between Treg subsets and disease activity.

Results

Total Tregs were expanded in ANCA vasculitis, which was associated with remission and the administration of rituximab and/or prednisone. The frequency of FOXP3Δ2 CD4+ T cells did not distinguish disease activity and this population had high expression levels of CD127 and lacked both CD25 and Helios, suggesting that they are not conventional Tregs. The frequency of CXCR3+, CD103+ and CCR7+ Tregs distinguished disease activity, and the combination of the frequency of these three Treg subsets segregated active patients from patients in remission and healthy controls. From these three subsets, the frequency of CXCR3+ Tregs distinguished patients with active disease with renal involvement.

Conclusion

Treg heterogeneity can discriminate disease activity and should be explored as a biomarker of disease activity in ANCA vasculitis.

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.

BVAS version 3 and BVAS/GPA: standing on the same line?

INTRODUCTION/OBJECTIVES

Birmingham vasculitis activity score (BVAS) version 3 (BVAS 3.0) and BVAS/granulomatosis with polyangiitis (BVAS/GPA) are used as indicators of disease activity in anti-neutrophil cytoplasmic antibody-associated vasculitis. We evaluated the association between these indices and the significance in patients with GPA and microscopic polyangiitis (GPA/MPA).

METHODS

We retrospectively reviewed the records of 203 patients with GPA/MPA in our hospital. The correlation between BVAS 3.0 and BVAS/GPA with the five-factor score (FFS) and laboratory data was investigated. The episodes of all-cause mortality, end-stage renal disease, and disease relapse were counted as adverse clinical outcomes. Multivariate Cox hazard analyses were performed to assess the relationships between both indices and patient outcomes.

RESULTS

Sixty-five (32.0%) and 138 (68.0%) patients with GPA and MPA were included. The median BVAS 3.0 was significantly higher in patients with MPA than in those with GPA (13.0 vs. 11.0, p = 0.015), whereas BVAS/GPA was higher in patients with GPA (4.0 vs. 3.0, p = 0.001). BVAS 3.0 and BVAS/GPA correlated significantly (r = 0.670, p < 0.001); both BVAS 3.0 and BVAS/GPA were shown to be associated with the outcomes investigated in separate Cox models. However, the correlation between BVAS 3.0 and BVAS/GPA was especially higher in a subgroup of patients with MPA than in those with GPA (MPA: r = 0.817, p < 0.001 vs. GPA: r = 0.570, p < 0.001) and with renal involvement (r = 0.676, p < 0.001).

CONCLUSIONS

Although both BVAS 3.0 and BVAS/GPA significantly correlated and predicted outcomes well in those with GPA/MPA, a discord was observed based on disease subtypes and organ involvement. Key Points • BVAS 3.0 and BVAS/GPA significantly correlated and predicted outcomes in those with GPA/MPA. • A discordance was also observed based on disease subtypes and organ involvement.

Diagnostic and Therapeutic Approach in ANCA-Associated Glomerulonephritis: A Review on Management Strategies

Anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis is a destructive small vessel vasculitis affecting multiple organs. Renal involvement often leads to end-stage renal disease and increases mortality. Prompt diagnosis and initiation of adequate immunosuppressive therapy are critical for the best patient and kidney outcomes. However, considerable heterogeneity in symptoms and severity across the patients frequently hinder the diagnosis and management. The objective of this review is to emphasize the heterogeneity of the ANCA-associated vasculitis, facilitate the recognition and give guidance to the therapeutical possibilities. We present epidemiologic and risk factors, pathogenesis, and provide comprehensive clinical features of the disease. This article also focuses on the currently available therapeutic options and emerging cellular and molecular targets for the management of systemic and especially renal disease. We conducted extensive literature research published on PubMed and Google Scholar. We systematically reviewed, analyzed, and assembled databases, covering a broad spectrum of aspects of the disease. We compared and summarized the recommendations of two recent guidelines on ANCA-associated vasculitis. The incidence of ANCA-associated vasculitis, hence glomerulonephritis shows a steady increase. Familiarity with the presenting symptoms and laboratory abnormalities are necessary for rapid diagnosis. Early initiation of treatment is the key aspect for favorable patient and renal outcomes. A better understanding of the pathogenesis constantly leads to more targeted and therefore more efficient and less toxic treatment.

Anti-Citrullinated Peptide Antibody Expression and Its Association with Clinical Features and Outcomes in Patients with Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

Background and objectives: Anti-citrullinated peptide antibody (ACPA), a characteristic antibody detected in rheumatoid arthritis, could be linked to antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) via the formation of neutrophil extracellular traps. We investigated the rate of ACPA positivity in patients with AAV and evaluated the association of ACPAs with their clinical features and outcomes. Materials and Methods: A total of 168 AAV patients with both ACPA and ANCA results at diagnosis were identified. Clinical and laboratory variables, including the disease-specific indices of Birmingham Vasculitis Activity Score (BVAS) and Five-Factor Score (FFS), were investigated. All-cause mortality, relapse, and end-stage renal disease, as well as interstitial lung disease (ILD) were evaluated as outcomes of the patients, and the Kaplan–Meier survival analysis was used to compare the event-free survival rates of the groups. Results: Fifteen (8.9%) and 135 (80.4%) patients were positive for ACPA and ANCA, respectively. There were no significant differences in the baseline variables of ACPA-negative and ACPA-positive patients. The absolute titre of ACPAs also did not significantly correlate with BVAS, FFS, erythrocyte sedimentation rate, or C-reactive protein. In addition, there was no difference noted regarding overall, relapse-free, and ESRD-free survival rates between ACPA-negative and ACPA-positive AAV patients. However, when the patients were divided into four groups according to ACPA and ANCA status, differences were present in the outcomes, and the ACPA-positive ANCA-positive group exhibited the lowest cumulative relapse-free survival rate, while no significant difference was present in the relapse between the ANCA-positive ANCA-positive, ACPA-positive ANCA-negative, and ACPA-negative ANCA-positive groups. Finally, the cumulative ILD-free survival rates were comparable between ACPA-positive and ACPA-negative AAV patients. Conclusions: The detection of ACPA expression is not uncommon in AAV. However, the presence of ACPA did not influence patients’ basal characteristics and outcomes, suggesting that further exploration of the role of this antibody is needed in patients with AAV.

Management and Outcomes of ANCA-Associated Vasculitis at a Tertiary Healthcare Facility

Results

Thirty-six patients were included in the final study. Cyclophosphamide was used in 24 patients (66.7%) and, comparatively, rituximab in 7 patients (19.4%) for induction. Seven patients (19.4%) had a documented relapse, and six patients (85.7%) had rituximab as induction therapy for relapse. The majority of patients were on azathioprine (61.1%, 57.1% relapse population) as maintenance therapy. Progression to ESRD occurred in 11 (30.6%), death in 4 (11.1%), established CKD in 15 (41.7%), and preservation of renal function in 6 (16.7%) patients by the end of the follow-up period.

Conclusions

While cyclophosphamide remains the choice of induction immunosuppression therapy, we favour rituximab as an induction agent in the relapse of AAV. Despite aggressive immunosuppression therapy, the incidence of ESRD and death remains high in these patients.

Induction and maintenance of remission with mycophenolate mofetil in ANCA-associated vasculitis: A systematic review and meta-analysis

BACKGROUND

Uncertainties exist about the use of mycophenolate mofetil (MMF) in anti-neutrophil cytoplasmatic antibody (ANCA)-associated vasculitis (AAV), particularly for remission maintenance.

METHODS

Systematic review and meta-analysis of phase II and III trials assessing the use of MMF in AAV (granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA)). A comprehensive search of several databases (Medline, EMBASE, Cochrane, Web of Science, Scopus) from inception to May 5th, 2020 has been conducted. Trial data were extracted to estimate odds ratios (ORs) and estimates (ES) for MMF efficacy (remission-induction and maintenance). Severe adverse effects (SAEs) were collected.

RESULTS

From 565 articles captured, 10 met the predefined criteria, five phase II and five III trials, 4 assessed remission-induction, 3 remission-maintenance, 3 both. The pooled OR for remission-induction at 6 months was 1.06 (95% CI: [0.74, 1.52]), with no significant difference by subgroup meta-analysis of trials stratified by different study-level features (i.e. kidney disease, MPA, myeloperoxidase-ANCA-positivity, newly diagnosed disease) (p > 0.05).The overall ES for remission-maintenance at the end of follow-up ranged between 51%-91% (I2 = 74.8%). Subgroup meta-analysis identified kidney involvement as a possible source of heterogeneity, yielding a significantly higher rate of sustained remission in trials enrolling only patients with kidney involvement (92% [76%-100%]) versus those enrolling patients with and without kidney involvement (56% [45%-66%]). Results were similar in multiple sensitivity analyses.During follow-up, the frequency of SAEs in MMF-based treatment arms was 31.8%.

CONCLUSIONS

In AAV, MMF use significantly associated with higher sustained remission rates in trials enrolling only patients with kidney involvement. These findings might influence clinical practice.

Predictors of renal and patient outcomes in anti-neutrophil cytoplasmic antibody-associated vasculitis: Our single-center, tertiary care experience

Objectives

This study aims to assess the different predictors of renal and patient prognosis in anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) patients with and without renal involvement.

Patients and methods

A total of 79 patients (51 males, 28 females; mean age: 57.3±14.2 years; range, 18 to 71 years) with AAV between January 2006 and November 2019 were retrospectively analyzed. Demographic and laboratory data including the complement 3 (C3) serum levels and renal biopsy findings were extracted from the electronic and printed medical records of the hospital registry. Survival, renal survival, remission, and relapse outcomes were analyzed.

Results

A total of 35% of the patients with renal involvement progressed to end-stage renal disease (ESRD). The dialysis requirement at the time of admission (hazard ratio [HR]: 21.95 [2.93-164.22]; p=0.003), estimated glomerular filtration rate (eGFR) (HR: 0.97 [0.94-0.99]; p=0.024) and Five-Factor Score (FFS) ≥2 at the time of diagnosis (HR: 3.59 [1.08-11.94]; p=0.037) were the predictors of ESRD. The five-year patient survival rate was 87.1%. The only predictor of mortality was age (HR: 1.07 [1.01-1.14]; p=0.024). The patients with hypocomplementemia (22%) had a lower remission rate (p=0.049), FFS ≥2 at the time of diagnosis (p=0.026), and higher levels of hematuria (p=0.004) and proteinuria (p=0.037). The FFS ≥2 at the time of diagnosis was an independent predictor of relapse (HR: 8.9 [1.02-77.36]; p=0.047).

Conclusion

Our study suggests that the baseline renal function and FFS ≥2 at the time of diagnosis are the major prognostic factors for progression to ESRD in AAV patients. In addition, AAV patients with hypocomplementemia may have a lower remission rate.

Risikostratifizierung bei ANCA-assoziierten Vaskulitiden

ANCA-assoziierte Vaskulitiden (AAV) sind nekrotisierende Vaskulitiden der kleinen bis mittelgroßen Gefäße, welche die Granulomatose mit Polyangiitis (GPA), die mikroskopische Polyangiitis (MPA) und die Eosinophile Granulomatose mit Polyangiitis (EGPA) umfassen. AAV gehen häufig mit Organfunktion-bedrohenden Manifestationen und einer entsprechend erhöhten Mortalität einher. Für die Planung von Diagnostik, Therapie und Langzeitbetreuung ist daher eine Risikostratifizierung im Hinblick auf Mortalität, Entwicklung schwerer Organinsuffizienzen, insbesondere einer terminalen Niereninsuffizienz, mögliche Therapieresistenz, Rezidive, Infektionen und Malignome erforderlich. Wichtige Risikofaktoren für erhöhte Mortalität und/oder terminale Niereninsuffizienz sind neben der renalen Beteiligung per se eine bereits zum Zeitpunkt der Diagnose deutlich eingeschränkte renale Funktion einschliesslich initialer Dialysepflichtigkeit, eine hohe initiale Aktivität der AAV gemessen am Birmingham Vaskulitis Activity Score, aber auch kardiale und gastrointestinale Manifestationen, Infektionen, Anämie sowie ein Alter von>65 Jahren. Histologisch ist der Nachweis chronischer irreversibler glomerulärer und tubulärer Läsionen in der Nierenbiopsie mit einer schlechten Prognose im Hinblick auf die Nierenfunktion assoziiert. Basierend auf der histopathologischen Klassifikation der ANCA-assoziierten Glomerulonephritis (GN) ist der Befund einer sklerosierenden GN mit einer besonders ungünstigen Prognose assoziiert, während die fokale GN sehr selten zur terminalen Niereninsuffizienz führt. MPO-ANCA zeigen eine Assoziation mit chronischen Läsionen in der Nierenbiopsie sowie erhöhter Mortalität und erhöhtem Risiko für terminale Niereninsuffizienz. Im Hinblick auf die pulmonale Beteiligung sind alveoläre Hämorrhagie und interstitielle Lungenerkrankung mit einer erhöhten Mortalität assoziiert. Bei EGPA wird die Prognose entscheidend durch die Kardiomyopathie bestimmt. Risikofaktoren für Rezidive weichen erheblich von denen für Mortalität und terminale Niereninsuffizienz ab. Ein erhöhtes Rezidivrisiko besteht bei Nachweis von PR3-ANCA, GPA und pulmonaler Beteiligung. Auch bei granulomatösen Läsionen, Beteiligung des oberen Respirationstraktes und kardiovaskulären Manifestationen wird ein erhöhtes Rezidivrisiko beschrieben. Im Gegensatz zur Assoziation einer initial schlechten Nierenfunktion mit Mortalität und terminaler Niereninsuffizienz, wurde für Patienten mit initial guter Nierenfunktion ein erhöhtes Rezidivrisiko gezeigt. Weitere Risikofaktoren für Rezidive sind Staphylokokken-Besiedelung der Nase, frühere Rezidive und ANCA-Positivität nach Remissionsinduktion. Titeranstieg oder Wiederauftreten von ANCA zeigen nur eine moderate Beziehung zum Rezidivrisiko. Der prädiktive Wert für Rezidive ist offenbar bei bestimmten Subgruppen, wie bei Patienten mit renaler Beteiligung und pulmonaler Hämorrhagie sowie bei mit Rituximab-behandelten Patienten besser als bei Patienten mit granulomatösen Manifestationen. Daher ist eine Therapieentscheidung allein auf Basis der Entwicklung der ANCA-Titer nicht möglich. Risikofaktoren für schwere Infektionen sind höher dosierte und prolongierte Glukokortikoidtherapie, Leuko- und Lymphopenie, höheres Lebenalter, Niereninsuffizienz und pulmonale Beteiligung. Die Malignomrate insbesondere für Nicht-Melanom-Hauttumoren, Harnblasenkarzinome und Leukämie ist bei AAV erhöht und zeigt eine Assoziation mit hohen kumulativen Cyclophosphamiddosen. Da insbesondere frühzeitige irreversible Organschäden die Prognose bestimmen und Rezidive die Entwicklung irreversibler Schäden treiben, sind frühestmögliche Diagnose und Therapie sowie rasches Erkennen und Vermeiden von Rezidiven essentiell für die Risikominimierung.

Usefulness of tissue inhibitor of metalloproteinase 1 as a predictor of sustained remission in patients with antineutrophil cytoplasmic antibody-associated vasculitis

Background

We previously identified tissue inhibitor of metalloproteinase 1 (TIMP-1) as a biomarker of disease activity that distinguished mildly or highly active antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) from remission 6 months after the initiation of remission-induction therapy. In the present study, we investigated whether TIMP-1 is clinically useful as a predictor of relapse and sustained remission in AAV patients with microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) during maintenance therapy.

Methods

The relationship between serum TIMP-1 levels and clinical outcomes in AAV patients receiving maintenance therapy was assessed using the follow-up data of a Japanese large-cohort study (the RemIT-JAV-RPGN study) and data collected from AAV patients on maintenance therapy in our hospital (the MAAV-EU study).

Results

In the RemIT-JAV RPGN study, serum levels of TIMP-1 were significantly higher in mildly active AAV patients with MPA and GPA 6 months after the initiation of remission-induction therapy than in patients in remission. Regarding maintenance therapy, elevated levels of TIMP-1 in patients in remission were associated with relapse and/or difficulty reducing the glucocorticoid dosage after 6 to 12 months. In the MAAV-EU study, serum levels of TIMP-1 were elevated in relapsed patients 6 months before relapse, earlier than the increase in serum levels of CRP. Analyses of both studies revealed that approximately 30% of patients in remission with a serum TIMP-1 level ≥ 150 ng/mL relapsed after 6 to 12 months, while the majority of patients with a TIMP-1 level < 150 ng/mL sustained remission for at least 12 months.

Conclusion

We herein demonstrated that TIMP-1 is more useful as a predictive biomarker of sustained remission than as a predictor of relapse in maintenance therapy for AAV. TIMP-1 levels < 150 ng/mL are important for the long-term maintenance of remission and may be an indicator for the tapering or cessation of treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02471-5.

Association between sinusitis and relapse and changes in the myeloperoxidase-antineutrophil cytoplasmic antibody in microscopic polyangiitis

Previous studies have evaluated the risk factors for relapse of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and the biomarkers of AAV for predicting relapse. However, little is known about the association between the presence of sinusitis and relapse and changes in the ANCA levels in AAV. This single-center, retrospective cohort study included 104 consecutive patients who were newly diagnosed with myeloperoxidase (MPO)-ANCA-positive microscopic polyangiitis (MPA) between 2006 and 2018 and were treated at the Aichi Medical University Hospital in Japan. The relationships between sinusitis and relapse of vasculitis and elevated MPO-ANCA levels were assessed using multivariate Cox proportional hazards models that were adjusted for clinically relevant factors. During the entire follow-up period (median, 24 months; interquartile range, 7-54 months), 93 (89.4%) patients achieved remission. After achieving remission, 38 (40.9%) patients experienced at least one relapse (13 [65.0%] in the sinusitis group; 25 [34.3%] in the non-sinusitis group). Sinusitis was identified as a significant predictor of relapse (adjusted hazard ratio: 2.41, 95% confidence interval [CI]: 1.19-4.88; P = 0.015). Furthermore, sinusitis was more likely to be associated with elevated MPO-ANCA levels (adjusted hazard ratio: 2.59, 95% CI: 1.14-5.92; P = 0.024). In conclusion, sinusitis was associated with a higher risk of relapse and elevated MPO-ANCA levels in MPA patients, suggesting that careful management may be required to reduce the risk of relapse in patients with sinusitis. Further studies are needed to elucidate the optimal treatment strategy for these patients.

Immunopathogenesis of ANCA-Associated Vasculitis

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis is an autoimmune disorder which affects small- and, to a lesser degree, medium-sized vessels. ANCA-associated vasculitis encompasses three disease phenotypes: granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). This classification is largely based on clinical presentations and has several limitations. Recent research provided evidence that genetic background, risk of relapse, prognosis, and co-morbidities are more closely related to the ANCA serotype, proteinase 3 (PR3)-ANCA and myeloperoxidase (MPO)-ANCA, compared to the disease phenotypes GPA or MPA. This finding has been extended to the investigation of biomarkers predicting disease activity, which again more closely relate to the ANCA serotype. Discoveries related to the immunopathogenesis translated into clinical practice as targeted therapies are on the rise. This review will summarize the current understanding of the immunopathogenesis of ANCA-associated vasculitis and the interplay between ANCA serotype and proposed disease biomarkers and illustrate how the extending knowledge of the immunopathogenesis will likely translate into development of a personalized medicine approach in the management of ANCA-associated vasculitis.