Overall survival, renal survival and relapse in patients with microscopic polyangiitis: a systematic review of current evidence

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.

Risk prediction model for mortality in microscopic polyangiitis: multicentre REVEAL cohort study

BACKGROUND

To establish refined risk prediction models for mortality in patients with microscopic polyangiitis (MPA) by using comprehensive clinical characteristics.

METHODS

Data from the multicentre Japanese registry of patients with vasculitis (REVEAL cohort) were used in our analysis. In total, 194 patients with newly diagnosed MPA were included, and baseline demographic, clinical, laboratory, and treatment details were collected. Univariate and multivariate analyses were conducted to identify the significant risk factors predictive of mortality.

RESULTS

Over a median follow-up of 202.5 (84-352) weeks, 60 (30.9%) of 194 patients died. The causes of death included MPA-related vasculitis (18.3%), infection (50.0%), and others (31.7%). Deceased patients were older (median age 76.2 years) than survivors (72.3 years) (P < 0.0001). The death group had shorter observation periods (median 128.5 [35.3-248] weeks) than the survivor group (229 [112-392] weeks). Compared to survivors, the death group exhibited a higher smoking index, lower serum albumin levels, higher serum C-reactive protein levels, higher Birmingham Vasculitis Activity Score (BVAS), higher Five-Factor Score, and a more severe European Vasculitis Study Group (EUVAS) categorization system. Multivariate analysis revealed that higher BVAS and severe EUVAS independently predicted mortality. Kaplan-Meier survival curves demonstrated lower survival rates for BVAS ≥20 and severe EUVAS, and a risk prediction model (RPM) based on these stratified patients into low, moderate, and high-risk mortality groups.

CONCLUSIONS

The developed RPM is promising to predict mortality in patients with MPA and provides clinicians with a valuable tool for risk assessment and informed clinical decision-making.

[Pharmacological and clinical profiles of avacopan (TAVNEOS® capsule), a selective C5a receptor antagonist]

Avacopan (TAVNEOS® capsules) is an orally available selective C5a receptor (C5aR) antagonist. It has been approved in Japan since 2021 for the treatment of microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA), the two major subtypes of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). The current standard therapy combining glucocorticoids (GC) and immunosuppressants has greatly improved the prognosis of AAV, however, issues such as side effects associated with GC use remain to be resolved. Avacopan suppresses priming of neutrophils induced by the complement component C5a, a process deeply involved in the pathogenesis of AAV. In pre-clinical studies, avacopan inhibited chemotaxis and priming of neutrophils induced by C5a-C5aR signaling. It also significantly suppressed nephritis and renal damage in an ANCA-induced glomerulonephritis mouse model. In the global phase 3 study "ADVOCATE", avacopan achieved both primary endpoints being 1) non-inferior to prednisone in inducing remission at week 26 and 2) superior in sustained remission at week 52 for MPA and GPA patients. Additionally, with avacopan, GC toxicity score was significantly lower and fewer adverse events possibly related to GC were observed. Furthermore, avacopan increased estimated glomerular filtration rate (eGFR) more than prednisone indicating improved renal function. Thus, the novel mechanism of avacopan targeting the complement system is a promising new therapeutic option for AAV with fewer GC-related side effects and better improvement of renal function.

Efficacy and safety of low- versus high-dose glucocorticoid regimens for induction of remission of anti-neutrophil cytoplasm antibody-associated vasculitis: a systematic review and meta-analysis

OBJECTIVE

Glucocorticoids (GCs) remain a cornerstone of the initial management of anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV), but have several dose-dependent side effects, in particular infections. The optimal dosing and tapering of oral GCs for remission induction are unknown. A systematic review and meta-analysis was undertaken to determine the efficacy and safety of low- versus high-dose GC regimens.

METHOD

A systematic search of MEDLINE, Embase, and PubMed databases was conducted. Clinical studies using a GC-based induction protocol were selected. A daily dose of 0.5 mg/kg or < 30 mg/day oral prednisolone equivalent by the start of week 4 of the induction tapering schedule marked the threshold between high- and low-dose GCs. Risk ratios (RRs) were calculated by the random effects model for outcomes of remission and infection. Relapse events were summarized using risk differences with 95% confidence intervals (CIs).

RESULTS

In total, 1145 participants were included in three randomized controlled trials and two observational studies, of whom 543 were assigned to the low-dose GC group and 602 to the high-dose GC group. A low-dose GC regimen was non-inferior to high-dose GCs with respect to outcomes of remission (RR 0.98, 95% CI 0.95-1.02, p = 0.37; I2 = 0%) and relapse (risk difference 0.03, 95% CI -0.01 to 0.06, p = 0.15; I2 = 12%), while significantly reducing the incidence of infection (RR 0.60, 95% CI 0.39-0.91, p = 0.02; I2 = 65%).

CONCLUSION

Studies with low-dose GC regimens in AAV are associated with fewer infections while obtaining equivalent efficacy.

Renal Recovery for Patients with ANCA-Associated Vasculitis and Low eGFR in the ADVOCATE Trial of Avacopan

Introduction

In the 330-patient ADVOCATE trial of avacopan for the treatment of antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis, in which 81% of patients had renal involvement, estimated glomerular filtration rate (eGFR) increased on average 7.3 ml/min per 1.73 m² in the avacopan group and 4.1 ml/min per 1.73 m² in the prednisone group (P = 0.029) at week 52. This new analysis examines the results in the patient subgroup with severe renal insufficiency at enrollment into the trial, i.e., eGFR ≤20 ml/min per 1.73 m².

Methods

eGFR was determined at baseline and over the course of the trial. Changes in eGFR were compared between the 2 treatment groups.

Results

In ADVOCATE, 27 of 166 patients (16%) in the avacopan group and 23 of 164 patients (14%) in the prednisone group had a baseline eGFR ≤20 ml/min per 1.73 m². At week 52, eGFR increased on average 16.1 and 7.7 ml/min per 1.73 m² in the avacopan and prednisone groups, respectively (P = 0.003). The last eGFR value measured during the 52-week treatment period was ≥2-fold higher than baseline in 41% of patients in the avacopan group compared to 13% in the prednisone group (P = 0.030). More patients in the avacopan group versus prednisone group had increases in eGFR above 20, 30, and 45 ml/min per 1.73 m², respectively. Serious adverse events occurred in 13 of 27 patients (48%) in the avacopan group and 16 of 23 patients (70%) in the prednisone group.

Conclusion

Among patients with baseline eGFR ≤20 ml/min per 1.73 m² in the ADVOCATE trial, eGFR improved more in the avacopan group than in the prednisone group.

Long-term clinical course and outcomes of patients with microscopic polyangiitis-associated interstitial lung disease

Background: Interstitial lung disease (ILD) is a significant complication associated with microscopic polyangiitis (MPA) that has a poor prognosis. However, the long-term clinical course, outcomes, and prognostic factors of MPA-ILD are not well defined. Hence, this study aimed to investigate the long-term clinical course, outcomes, and prognostic factors in patients with MPA-ILD. Methods: Clinical data of 39 patients with MPA-ILD (biopsy proven cases, n = 6) were retrospectively analyzed. High resolution computed tomography (HRCT) patterns were assessed based on the 2018 idiopathic pulmonary fibrosis diagnostic criteria. Acute exacerbation (AE) was defined as the worsening of dyspnea within 30 days, with new bilateral lung infiltration that is not fully explained by heart failure or fluid overload and that does not have identified extra-parenchymal causes (pneumothorax, pleural effusion, or pulmonary embolism). Results: The median follow-up period was 72.0 months (interquartile range: 44-117 months). The mean age of the patients was 62.7 years and 59.0% were male. Usual interstitial pneumonia (UIP) and probable usual interstitial pneumonia patterns on high resolution computed tomography were identified in 61.5 and 17.9% of the patients, respectively. During the follow-up, 51.3% of patients died, and the 5- and 10-year overall survival rates were 73.5% and 42.0%, respectively. Acute exacerbation occurred in 17.9% of the patients. The non-survivors had higher neutrophil counts in bronchoalveolar lavage (BAL) fluid and more frequent acute exacerbation than the survivors. In the multivariable Cox analysis, older age (hazard ratio [HR], 1.07; 95% confidence interval [CI], 1.01-1.14; p = 0.028) and higher BAL counts (HR, 1.09; 95% CI, 1.01-1.17; p = 0.015) were found to be the independent prognostic factors associated with mortality in patients with MPA-ILD. Conclusion: During the 6 years-follow-up, about half of patients with MPA-ILD died and approximately one-fifth experienced acute exacerbation. Our results suggest that older age and higher BAL neutrophil counts mean poor prognosis in patients with MPA-ILD.

Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis in Kidney Transplantation

Due to complex comorbidity, high infectious complication rates, an elevated risk of relapsing for primary renal disease, as well as inferior recipient and allograft survivals, individuals with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAVs) are often considered as poor transplant candidates. Although several aspects of recurrent and de novo AAVs remain unclear, recent evidence suggests that kidney transplantation (KT) represents the best option, which is also the case for this particular subgroup of patients. Special counselling and individualized approaches are strongly recommended at the time of enlistment and during the entire post-transplant follow-up. Current strategies include avoiding transplantation within one year of complete clinical remission and thoroughly assessing the recipient for early signs of renal or systemic vasculitis. The main clinical manifestations of allograft AAV are impaired kidney function, proteinuria, and hematuria with ANCA positivity in most cases. Mixed results have been obtained using high-dose steroids, mycophenolate mofetil, or cyclophosphamide. The aim of the present review was to summarize the available literature on AAVs in KT, particularly focusing on de novo pauci-immune glomerulonephritis.

Rapidly worsening pneumonia in a middle-aged woman: a rare diagnosis and a crucial management decision

A 54-year-old Indian female presented to the hospital with a 4-day history of fever, shortness of breath and blood-streaked sputum. Chest radiograph showed consolidation and she was admitted as a case of bilateral bronchopneumonia. She was started on broad-spectrum antibiotics and antivirals but she continued to deteriorate clinically with increasing oxygen requirement and worsening lung infiltrates. Since lab investigations also revealed significant anaemia and renal impairment, vasculitic workup for pulmonary renal haemorrhagic syndrome was ordered even though she had no haemoptysis in the hospital and haemoglobin was stable after initial blood transfusion. High-resolution computed tomography scan was done on day 5 to assess progression and for any clue to diagnosis. It showed extensive bilateral air space consolidation and ground-glass opacities with suggested radiological differential diagnosis of cryptogenic organising pneumonia or pulmonary haemorrhage. Pulmonology team did not recommend bronchoscopy at the time.In view of the clinical features of rapidly progressing pneumonia despite standard treatment, history of haemoptysis, anaemia, renal impairment and CT scan findings suggestive of pulmonary haemorrhage, pulse intravenous Methylprednisolone was initiated. The patient showed marked clinical and radiological improvement. The vasculitic workup later revealed positive myeloperoxidase antibody and a definitive diagnosis of microscopic polyangiitis was made. She was discharged in a stable condition and advised to follow-up in rheumatology where she continues to follow-up 2 years after her initial diagnosis.This is the first case reported in literature, where treatment was initiated for this rare disease entity within a week of presentation based on highly suggestive clinical, laboratory and radiological evidence without waiting for a confirmatory diagnosis. Delay in this rapidly deteriorating patient could have been fatal and our prompt action was crucial in securing a favourable outcome.

Avacopan for the Treatment of ANCA-Associated Vasculitis

BACKGROUND

The C5a receptor inhibitor avacopan is being studied for the treatment of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis.

METHODS

In this randomized, controlled trial, we assigned patients with ANCA-associated vasculitis in a 1:1 ratio to receive oral avacopan at a dose of 30 mg twice daily or oral prednisone on a tapering schedule. All the patients received either cyclophosphamide (followed by azathioprine) or rituximab. The first primary end point was remission, defined as a Birmingham Vasculitis Activity Score (BVAS) of 0 (on a scale from 0 to 63, with higher scores indicating greater disease activity) at week 26 and no glucocorticoid use in the previous 4 weeks. The second primary end point was sustained remission, defined as remission at both weeks 26 and 52. Both end points were tested for noninferiority (by a margin of 20 percentage points) and for superiority.

RESULTS

A total of 331 patients underwent randomization; 166 were assigned to receive avacopan, and 165 were assigned to receive prednisone. The mean BVAS at baseline was 16 in both groups. Remission at week 26 (the first primary end point) was observed in 120 of 166 patients (72.3%) receiving avacopan and in 115 of 164 patients (70.1%) receiving prednisone (estimated common difference, 3.4 percentage points; 95% confidence interval [CI], -6.0 to 12.8; P<0.001 for noninferiority; P = 0.24 for superiority). Sustained remission at week 52 (the second primary end point) was observed in 109 of 166 patients (65.7%) receiving avacopan and in 90 of 164 patients (54.9%) receiving prednisone (estimated common difference, 12.5 percentage points; 95% CI, 2.6 to 22.3; P<0.001 for noninferiority; P = 0.007 for superiority). Serious adverse events (excluding worsening vasculitis) occurred in 37.3% of the patients receiving avacopan and in 39.0% of those receiving prednisone.

CONCLUSIONS

In this trial involving patients with ANCA-associated vasculitis, avacopan was noninferior but not superior to prednisone taper with respect to remission at week 26 and was superior to prednisone taper with respect to sustained remission at week 52. All the patients received cyclophosphamide or rituximab. The safety and clinical effects of avacopan beyond 52 weeks were not addressed in the trial. (Funded by ChemoCentryx; ADVOCATE ClinicalTrials.gov number, NCT02994927.).

Clinical Significance of Interstitial Lung Disease and Its Acute Exacerbation in Microscopic Polyangiitis

BACKGROUND

Presence of interstitial lung disease (ILD) is thought to be associated with mortality in microscopic polyangiitis (MPA); however, evidence on MPA-ILD remains lacking. Acute exacerbation (AE) refers to rapidly progressive, fatal respiratory deterioration that may develop in patients with various ILDs. No study has investigated the clinical significance of AE in MPA-ILD.

RESEARCH QUESTION

We aimed to determine the clinical picture and prognostic factors, the incidence of AE, and the risk factors in patients with MPA-ILD.

STUDY DESIGN AND METHODS

Eighty-four consecutive patients with MPA-ILD and 95 patients with MPA-non-ILD were analyzed. We also compared 80 patients with MPA-ILD and 80 patients with idiopathic interstitial pneumonia without myeloperoxidase-antineutrophil cytoplasmic antibody positivity (ILD alone), who were matched for age, sex, and chest high-resolution CT scan pattern.

RESULTS

The MPA-ILD group had a higher frequency of men and smokers and was associated with higher mortality than the MPA-non-ILD group. The matched MPA-ILD group had a higher mortality rate than the matched ILD alone group. There was no significant difference in AE incidence between the matched MPA-ILD and ILD alone groups (1-year AE cumulative incidence rate, 7.5% and 5.2%, respectively; P = .75). In the MPA-ILD group, a lower percent predicted FVC (%FVC) was independently associated with a higher mortality rate (hazard ratio [HR], 0.96 per 1% increase; P < .01) and a higher AE incidence rate (HR, 0.96 per 1% increase; P = .01). On multivariable Cox regression analysis with time-dependent covariates, developing AE during their clinical course was strongly associated with shorter survival (HR, 17.1; P < .001).

INTERPRETATION

MPA-ILD represented a distinct phenotype with poor prognosis. Lower %FVC was an independent prognostic factor. Patients with lower %FVC had a risk of developing AE, which was a strong prognostic determinant. The specific management for MPA-ILD and AE should be established.

Evaluation of the Safety and Efficacy of Avacopan, a C5a Receptor Inhibitor, in Patients With Antineutrophil Cytoplasmic Antibody-Associated Vasculitis Treated Concomitantly With Rituximab or Cyclophosphamide/Azathioprine: Protocol for a Randomized, Double-Blind, Active-Controlled, Phase 3 Trial

Background

Antineutrophil cytoplasmic antibody (ANCA)–associated vasculitis is a serious, often life-threatening disease. In new-onset disease or a relapse, the standard treatment is immunosuppressive therapy with glucocorticoids; these therapies are associated with substantial short- and long-term toxicity. Complement component 5a (C5a) binding to C5a receptor (C5aR) may play a central role in the pathogenesis of ANCA-associated vasculitis. Avacopan is a novel, orally bioavailable, and highly selective antagonist of human C5aR. Avacopan does not interfere with the production of C5b or the membrane attack complex (ie, terminal complement complex) and does not block C5a binding to a second receptor, C5L2 (also called C5aR2), shown to be protective in antimyeloperoxidase glomerulonephritis. This trial will evaluate if avacopan replaces the need for chronic glucocorticoids in the treatment of ANCA-associated vasculitis.

Objective

The aim of this study is to determine the proportions of patients in remission at week 26 and with sustained remission at week 52, defined as Birmingham Vasculitis Activity Score=0, and not taking glucocorticoids within the 4 weeks before week 26 and week 52, respectively.

Methods

The Avacopan Development in Vasculitis to Obtain Corticosteroid elimination and Therapeutic Efficacy study is a randomized, double-blind, active-comparator (prednisone), 2-arm study evaluating the safety and efficacy of avacopan versus prednisone, administered in combination with other immunosuppressive therapy. Eligible subjects will have active disease requiring induction of remission. Subjects are stratified based on the type of immunosuppressive therapy, ANCA subtype, and new or relapsing disease. Target sample size is 300 patients, enrolled at over 200 sites globally. All authors and local ethics committees approved the study design. All patients will provide informed consent.

Results

Enrollment of patients was completed in Q4 2018. Topline results are anticipated to be published by Q3 2020.

Conclusions

Results will be released irrespective of whether the findings are positive or negative.

Trial Registration

ClinicalTrials.gov NCT02994927; https://clinicaltrials.gov/ct2/show/NCT02994927

International Registered Report Identifier (IRRID)

DERR1-10.2196/16664

Long-term outcome of renal transplantation in childhood-onset anti-neutrophil cytoplasmic antibody-associated vasculitis

BACKGROUND

There have been a few reports of RTx for AAV in children; however, post-transplant recurrence rate and long-term prognosis remain unclear. Here, we describe the long-term outcomes of RTx in childhood-onset AAV.

METHODS

We conducted a retrospective study of children who underwent RTx for AAV between 1999 and 2017 and had a follow-up period of >2 years.

RESULTS

Seven patients consisting of three children with MPA and four with RLV were analyzed. Age at Dx was 5.9 (median; range, 4.1-14.5) years. PD was instituted in all patients, and median time on dialysis was 26 (range, 14-63) months. Age at RTx was 12.8 (median; range, 8.7-16.3) years. There were no recurrences of AAV noted during the median follow-up period of 7.0 (range, 2.7-18.8) years after RTx. Graft loss occurred in one patient due to non-adherence. Estimated glomerular filtration rate of the remaining patients at the last follow-up was 73.0 (median; range, 50.7-93.9) mL/min/1.73 m² . No malignancies and deaths occurred during the observational period.

CONCLUSIONS

Our study suggests that RTx for AAV with ESRD is a potentially safe and effective treatment choice for children with AAV.

ANCA associated vasculitis: The journey to complement-targeted therapies

ANCA associated vasculitis is a serious, very often recurrent disease that despite the current standard treatment with high-dose glucocorticoids and either cyclophosphamide or rituximab, patients have a nine-fold increased mortality risk in the first year compared with healthy controls, attributed to infections, vasculitis activity, and renal disease. During the last few years, novel findings have suggested that activation of the complement system, in particular the alternative complement system, has a significant role in ANCA associated vasculitis pathogenesis. Detection of several components of this system in the circulation and urine reflects disease activity, and thus may be useful for clinical prognosis and to set up personalised treatments. In fact, some components of the complement system, such as C5a, might be potential targets for therapy. In this Review an update on clinical evidence for the role of complement activation in AAV is provided and subsequently we discuss potential therapeutic strategies that target complement components and open the way for clinical use of this target therapy in the near future.

Prevalence and Risk Factors for Major Infections in Patients with Antineutrophil Cytoplasmic Antibody-associated Vasculitis: Influence on the Disease Outcome

OBJECTIVE

To analyze the role that infections play on the antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) outcome.

METHODS

A retrospective study of adult patients with AAV diagnosed in a tertiary center. Clinical features, laboratory findings, treatment, relapses, major infections, and outcome were evaluated.

RESULTS

Included were 132 patients [51 microscopic polyangiitis (MPA), 52 granulomatosis with polyangiitis (GPA), 29 eosinophilic GPA (EGPA)] with a mean followup of 140 (96-228) months. ANCA were positive in 85% of cases. A total of 300 major infections, mainly bacterial (85%), occurred in 60% patients during the followup. Lower respiratory tract (64%) and urinary tract infections (11%) were the most frequent, followed by bacteremia (10%). A total of 7.3% opportunistic infections were observed, most due to systemic mycosis. Up to 46% of all opportunistic infections took place in the first year of diagnosis, and 55% of them under cyclophosphamide (CYC) treatment. Bacterial infections were associated with Birmingham Vasculitis Activity Score (version 3) > 15 at the disease onset, a total cumulative CYC dose > 8.65 g, dialysis, and development of leukopenia during the followup. Leukopenia was the only factor independently related to opportunistic infections. Forty-four patients died, half from infection. Patients who had major infections had an increased mortality from any cause.

CONCLUSION

Our results confirm that major infections are the main cause of death in patients with AAV.

Prognostic nutritional index is associated with disease severity and relapse in ANCA-associated vasculitis

AIM

The prognostic nutritional index (PNI), calculated by serum albumin and peripheral blood lymphocyte count, is considered to reflect immune-related nutritional status. In this study, we first investigated the clinical significance of PNI in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV).

METHOD

Medical records of 160 patients classified as AAV from October 2000 to September 2017 were reviewed. We calculated the Birmingham vasculitis activity score (BVAS) and collected laboratory data including erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, white blood cell, lymphocyte, and platelet counts, and serum albumin, aspartate aminotransferase, and alanine aminotransferase levels at diagnosis. PNI at diagnosis was calculated as (10 × serum albumin [g/dL] + 0.005 × lymphocyte count [/mm³ ]). Associations between laboratory variables, PNI, and BVAS were assessed by linear regression analyses, and Cox proportional hazard analysis was used to evaluate factors associated with disease relapse.

RESULTS

The mean age was 55.2 years and 48 patients (30.0%) were male. In univariable linear regression analysis, BVAS was positively correlated with ESR and CRP and negatively with lymphocyte count, serum albumin, and PNI (r = -0.307). In multivariable linear regression analysis, among ESR, CRP, and PNI, PNI was associated with BVAS (β = -0.299). PNI also significantly correlated with the included laboratory data. In Cox proportional hazard analysis, myeloperoxidase-antineutrophil cytoplasmic antibody positivity (odds ratio [OR] 2.875, P = 0.003) and PNI ≤36.75 (OR 2.066, P = 0.042) revealed to be independent predictors of disease relapse during the follow-up period.

CONCLUSIONS

Prognostic nutritional index at diagnosis might be useful for assessing disease severity and predicting the prognosis of AAV patients.

Clinical features of kidney involvement in microscopic microscopic polyangiitis

AIM

To evaluate clinical features and outcomes of renal involvement in patients with microscopic polyangiitis (MPA).

MATERIALS AND METHODS

We enrolled 99 patients with MPA, diagnosed in accordance with the algorithm of the European Medicines Evaluation Agency (EMEA) and the Chapel Hill consensus conference definition (2012). Serum creatinine (sCr), estimated glomerular filtration rate (eGFR), hematuria and proteinuria were estimated. Frequency of rapidly progressive renal failure (a twofold increase in the sCr level in ≤3 months) was regarded as the clinical equivalent of rapidly progressive glomerulonephritis (RPGN).

RESULTS

Renal involvement was present in 92 (92.9%) patients. RPGN developed in 51 (55,4%) patients. The most common features of kidney involvement were hematuria and subnephrotic proteinuria. Arterial hypertension was revealed in 32 (34.7%) patients and was associated with RPGN (p&lt;0.004). End-stage renal disease (ESRD) developed in 11 (11.9%) patients. Despite effective induction therapy disease relapses occurred in 20 (21.1%) patients during the 1st year, including renal relapses in 12 (13.3%) cases. During 5-year follow up 34 (37.1%) patients developed disease relapses, including renal relapses in 22 (24.4%) patients.

CONCLUSION

Renal involvement is one of the most common manifestations of MPA with a high frequency of RPGN. More than one third of patients develop disease relapses despite adequate therapy.

Clinical Predictors of Outcome in Patients with Anti-neutrophil Cytoplasmic Autoantibody-related Renal Vasculitis: Experiences from a Single-center

Background:

Primary anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) is a chronic autoimmune disease associated with multisystem dysfunction. Renal involvement is common and closely associated with outcome. The purpose of this study was to investigate the clinical determinants of mortality of patients with AAV-related renal injury in the first 2 years after diagnosis in a single West Chinese center.

Methods:

Demographic and laboratory parameters of 123 consecutive patients with AAV-related renal injury diagnosed in Renal Division and Institute of Nephrology, Sichuan Provincial People's Hospital between 2004 and 2012 were collected retrospectively. All patients were followed up for 2 years after diagnosis. Survivors were compared with nonsurvivors to identify the clinical baseline variables associated with mortality. Multivariate Cox regression model was used to determine the independent predictors of mortality.

Results:

Of the 123 patients, 46 (37.4%) died by the end of 2 years after diagnosis, with 41 (33.3%) patients dying within the first 12 months. In comparison with the survivors, Birmingham Vasculitis Activity Score (BVAS), the incidence of pulmonary hemorrhage and digestive system (DS) involvement, serum creatinine, and erythrocyte sedimentation rate were significantly higher in nonsurvivors, whereas lymphocyte counts, hemoglobin, and complement 3 (C3) were significantly lower. Renal replacement therapy was more common in nonsurvivors. High BVAS (hazard ratio [HR] = 1.058, 95% confidence interval [CI]: 1.002–1.117; P = 0.042), pulmonary hemorrhage (HR = 1.970, 95% CI: 1.033–3.757; P = 0.04), DS involvement (HR = 2.911, 95% CI: 1.212–6.911; P = 0.017), and serum creatinine >400 μmol/L (HR = 2.910, 95% CI: 1.271–6.664; P = 0.012) were independent predictors of death in patients with AAV-related renal injury.

Conclusions:

Patients with AAV-related renal injury have high early mortality. Those with high BVAS (particularly with pulmonary or DS involvement) and serious renal dysfunction should receive aggressive therapy and careful monitoring to reduce the occurrence of adverse events and improve prognosis.

Negative anti-neutrophil cytoplasm antibody at switch to maintenance therapy is associated with a reduced risk of relapse

BACKGROUND

Relapse of disease is frequent in anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV). It is unclear whether persistent ANCA when starting maintenance therapy increases the risk of relapse. We examined the association between ANCA status and relapse in two randomised controlled trials.

METHODS

ANCA-positive patients in two trials, CYCLOPS and IMPROVE, were switched from cyclophosphamide to maintenance therapy after achieving clinical remission. We classified patients as being either ANCA-positive or ANCA-negative at the time they started maintenance therapy. We compared the risk of relapse in ANCA-positive and ANCA-negative patients.

RESULTS

Of 252 patients included, 102 (40%) experienced at least one relapse during the follow-up period. At the time of the switch from induction to maintenance therapy, 111 were ANCA-positive, of whom 55 (50%) relapsed, compared to 141 patients who were ANCA-negative, of whom 47 (33%) relapsed. In multivariable time-to-event analysis, a reduced risk of relapse was associated with having become ANCA-negative at the time of switching to maintenance therapy (hazard ratio 0.63, 95% confidence interval 0.42-0.95; p = 0.026). In addition, initial proteinase 3 (PR3)-ANCA, younger age, lower serum creatinine, pulsed cyclophosphamide for remission induction, and mycophenolate mofetil for remission maintenance were all associated with an increased risk of relapse.

CONCLUSIONS

Becoming ANCA-negative before the switch to maintenance is associated with a reduced risk of relapse.

TRIAL REGISTRATION

CYCLOPS: ClinicalTrials.gov, NCT00430105 . Registered retrospectively on 31 January 2007.

IMPROVE

ClinicalTrials.gov, NCT00307645 . Registered retrospectively on 27 March 2006.

Mortality in ANCA-associated vasculitis: ameta-analysis of observational studies

Objective

To determine the magnitude of all-cause mortality risk in patients with antineutrophil cytoplasmic antibodies-associated vasculitis (AAV) compared with the general population through a meta-analysis of observational studies.

Methods

We searched Medline and Embase databases from their inception to April 2015. Observational studies that met the following criteria were assessed by two researchers: (1) clearly defined AAV identified by either the American College of Rheumatology 1990 classification criteria or the 2012 Chapel Hill Consensus Conference disease definitions, and (2) reported standardised mortality ratios (SMR) and 95% CI. We calculated weighted-pooled summary estimates of SMRs (meta-SMRs) for all-cause mortality using random-effects model, tested for publication bias and heterogeneity.

Results

Ten studies met the inclusion criteria, comprising 3338 patients with AAV enrolled from 1966 to 2009, and a total of 1091 observed deaths. Overall, we found a 2.7-fold increased risk of death in patients with AAV when compared with the general population (meta-SMR: 2.71 (95% CI 2.26 to 3.24)). Analysis on studies that included only granulomatosis with polyangiitis cases also indicated a similar mortality risk (meta-SMR: 2.63 (95% CI 2.02 to 3.43)). There was no significant publication bias or small-study effect. Subgroup analyses showed that mortality risks were higher in older cohorts, with a trend towards improvement over time (ie, those with their midpoint of enrolment periods that were between 1980–1993 and 1994–1999, vs 2000–2005).

Conclusion

Published data indicate there is a 2.7-fold increase in mortality among patients with AAV compared with the general population.

Elevated serum levels of immunoglobulin A correlate with the possibility of readmission in patients with microscopic polyangiitis

BACKGROUND

The evidence for the short-term prognosis of patients with microscopic polyangiitis (MPA) is weak, and the objective of this study was to analyze the clinical features of the disease and evaluate the risk factors for readmission in patients with MPA.

METHODS

Fifty-seven patients with MPA were recruited into this study. The clinical data of these MPA patients were collected. Clinical manifestations, laboratory results, and imaging results were analyzed. Patients who were readmitted to our hospital within 6 months after their first diagnosis and treatment of MPA were defined as the readmission group; the remaining patients were defined as the control group.

RESULTS

Respiratory symptoms, including cough, dyspnea (87.72%), and hemoptysis (3.51%), seemed to be the initial symptoms in many patients with MPA. Systemic symptoms included fever (71.93%), hearing loss (12.28%), vision loss (3.51%), and joint involvement (5.27%). The D-dimer levels of 43 patients (75.44%) were >500 ng/dL, and only three of these patients had venous thrombosis. Age and immunoglobulin A (IgA) were the risk factors for readmission in patients with MPA, with odds ratios (ORs) of 1.162 [95% confidence interval (CI): 1.025-1.317, P=0.019] and 1.010 (95% CI: 1.001-1.018, P=0.028). The days of hospitalization and the a2-globulin level were protective factors with ORs of 0.849 (95% CI: 0.725-0.993 P=0.041) and 0.789 (95% CI: 0.64-0.971, P=0.025), respectively. IgA levels were positively correlated with the number of hospitalizations, with a correlation coefficient of 0.428 (P=0.002). Receiver operating characteristic curve analysis showed that the possibility of readmission increases when the serum levels of IgA were >217.5 mg/dL.

CONCLUSION

The level of serum IgA is a risk factor for the readmission of patients with MPA, and correlated with the number of hospitalizations in these patients.

Pre-existing chronic interstitial pneumonia is a poor prognostic factor of Goodpasture's syndrome: a case report and review of the literature

BACKGROUND

Goodpasture's syndrome is a rare disease that is characterized by rapidly progressive glomerulonephritis and diffuse alveolar hemorrhage.

CASE PRESENTATION

A 71-year-old Japanese man who had chronic interstitial pneumonia was diagnosed as having Goodpasture's syndrome. Both anti-glomerular basement membrane antibody and myeloperoxidase anti-neutrophil cytoplasmic antibody were increased. Despite intensive treatments, including mechanical ventilation, he died from respiratory failure. Pathological findings at autopsy showed rapidly progressive glomerulonephritis in his kidneys, diffuse alveolar hemorrhage, hyaline membranes, and fibroblastic foci in his lungs. The cause of death was diagnosed as respiratory failure as a result of diffuse alveolar damage induced by a combination of diffuse alveolar hemorrhage and exacerbation of interstitial pneumonia.

CONCLUSIONS

We report a case of Goodpasture's syndrome complicated with pre-existing chronic interstitial pneumonia and positive myeloperoxidase anti-neutrophil cytoplasmic antibody. We reviewed six similar cases reported in the literature and concluded that Goodpasture's syndrome with pre-existing interstitial pneumonia and myeloperoxidase anti-neutrophil cytoplasmic antibody is related to a poor prognosis.

Randomized Trial of C5a Receptor Inhibitor Avacopan in ANCA-Associated Vasculitis

Alternative C activation is involved in the pathogenesis of ANCA-associated vasculitis. However, glucocorticoids used as treatment contribute to the morbidity and mortality of vasculitis. We determined whether avacopan (CCX168), an orally administered, selective C5a receptor inhibitor, could replace oral glucocorticoids without compromising efficacy. In this randomized, placebo-controlled trial, adults with newly diagnosed or relapsing vasculitis received placebo plus prednisone starting at 60 mg daily (control group), avacopan (30 mg, twice daily) plus reduced-dose prednisone (20 mg daily), or avacopan (30 mg, twice daily) without prednisone. All patients received cyclophosphamide or rituximab. The primary efficacy measure was the proportion of patients achieving a ≥50% reduction in Birmingham Vasculitis Activity Score by week 12 and no worsening in any body system. We enrolled 67 patients, 23 in the control and 22 in each of the avacopan groups. Clinical response at week 12 was achieved in 14 of 20 (70.0%) control patients, 19 of 22 (86.4%) patients in the avacopan plus reduced-dose prednisone group (difference from control 16.4%; two-sided 90% confidence limit, -4.3% to 37.1%; P=0.002 for noninferiority), and 17 of 21 (81.0%) patients in the avacopan without prednisone group (difference from control 11.0%; two-sided 90% confidence limit, -11.0% to 32.9%; P=0.01 for noninferiority). Adverse events occurred in 21 of 23 (91%) control patients, 19 of 22 (86%) patients in the avacopan plus reduced-dose prednisone group, and 21 of 22 (96%) patients in the avacopan without prednisone group. In conclusion, C5a receptor inhibition with avacopan was effective in replacing high-dose glucocorticoids in treating vasculitis.

Renal vasculitis presenting with acute kidney injury

Renal failure secondary to ANCA-associated vasculitis represents a clinical and therapeutic challenge. In this study, we aimed to assess the treatment response rates and long-term outcomes of vasculitis patients presenting with renal failure. This retrospective study included 151 patients with renal vasculitis from three hospitals who underwent a renal biopsy between 1997 and 2014. Patients with renal failure which required dialysis at the onset were compared to those presenting with more preserved renal function. The primary end point was treatment response and patient surivival. Patients with severe renal involvement had a lower response to treatment compared to those having preserved renal function (26.6 versus 93.4%; p < 0.001). Dialysis-dependent patients who received plasmapheresis in addition to immune suppressants associated a higher rate of renal recovery (41.6 versus 12.5%; p = 0.05). A higher incidence of severe infections was observed among patients with severe renal involvement (38.4 versus 18.1%, p = 0.01). The mortality rate was significantly higher among vasculitis patients presenting with renal failure (53.8 versus 22.2%, p = 0.001). Global survival at 1 and 5 years was 60 and 47% in patients requiring dialysis compared with 90 and 80% among those with more preserved renal function (p < 0.001). After multivariate adjustment, the need for dialysis remained as an independent predictor of death (HR 2.5; 95% CI 1.1-5.7; p = 0.03). The presence of severe renal dysfunction represents an independent risk factor for patient survival in renal vasculitis. Patients requiring dialysis associate a lower response rate to immunosuppressive therapy and a higher incidence of severe infections.

Simple, readily available clinical indices predict early and late mortality among patients with ANCA-associated vasculitis

Background

The early identification of patients with ANCA-associated vasculitis (AAV) who are at increased risk for inferior clinical outcome at the time of diagnosis might help to optimize the immunosuppressive therapy. In this study we wanted to determine the predictive value of simple clinical characteristics, which may be applicable for early risk-stratification of patients with AAV.

Methods

We retrospectively analyzed the outcome of 101 consecutive patients with AAV receiving a protocolized immunosuppressive therapy. Baseline Birmingham Vasculitis Activity Score (BVAS) and non-vasculitic comorbidities were computed, then predictors of early (<90 days) and late (>90 days) mortality, infectious death, relapse and end stage kidney disease (ESKD) were evaluated.

Results

The baseline comorbidity score independently predicted early mortality (HR 1.622, CI 1.006–2.614), and showed association with infectious mortality (HR 2.056, CI 1.247–3.392). Patients with BVAS at or above median (=21) had worse early mortality in univariable analysis (HR 3.57, CI 1.039–12.243) (p = 0.031), and had more frequent relapses (p = 0.01) compared to patients with BVAS below median.

Conclusions

Assessing baseline comorbidities, beside clinical indices characterizing the severity and extension of AAV, might help clinicians in risk-stratification of patients. Future prospective studies are needed to investigate whether therapies based on risk-stratification could improve both short term and long term survival.

Therapy and prognosis of ANCA-associated vasculitis from the clinical nephrologist's perspective

This paper reviews the recently published scientific information regarding ANCA-associated vasculitis (AAV), aiming to highlight the most important data from the clinical nephrologists' perspective. The classification, pathomechanism, recent achievements of the treatment, short-term and long-term outcomes of the disease, and the difficulties nephrologists face when taking care for patients with AAV are summarized. There has been significant progress in the understanding of the genetic and pathologic background of the disease in the last years, and results of histological studies guide us to predict long-term renal function. Findings of several multicentered trials with reasonable number of participants provide comparison of the efficacy and safety of different remission induction and maintenance therapies, and evaluate recently introduced immunosuppressive agents. Although the clinical outcome of patients with AAV has improved significantly since modern immunosuppressive drugs are available, the treatment-related complications still contribute to the morbidity and mortality. To improve the survival and quality of life of patients with AAV further, knowledge of the predictors of relapse, end-stage kidney disease, and mortality, also prevention of infections and other treatment-related adverse events are important. The eligibility for renal transplantation and the option for successful pregnancies for young women are also important factors which influence the patients' quality of life. In order to provide favorable outcome, the clinicians need to establish personalized treatment strategies to optimize the intensity and minimize the toxicity of the immunosuppressive therapy.

Plasma exchange for paediatric kidney disease-indications and outcomes: a single-centre experience

BACKGROUND

Outcome data in paediatrics regarding the use of plasmapheresis for immunological kidney disease are scarce.

OBJECTIVES

We aimed to evaluate the role of plasmapheresis in children presenting with severe renal impairment secondary to immunological kidney diseases.

METHODS

A retrospective chart review of children admitted between January 2009 and August 2013 to the Paediatric Nephrology Unit, Christian Medical College, Vellore, India, and requiring plasma exchange was undertaken. Demographic and clinical data were studied and descriptive statistics applied for analysis.

RESULTS

Sixteen children underwent plasmapheresis with a male:female ratio of 10:6 and a mean age of 10.2 years (range 5-15 years). Twelve children had atypical haemolytic uraemic syndrome, two had anti-glomerular basement disease and one each had lupus nephritis with neurological manifestation and anti-nuclear cytoplasmic antibody-associated vasculitis. The mean serum creatinine at presentation was 6.52 [interquartile range (IQR) 4.96-7.85] mg/dL with a mean eGFR of 43 (IQR 27.54-56.7) mL/min/1.73 m(2). Other presenting features included nephrotic range proteinuria (69%), gross haematuria (27%), hypertension (94%) and seizures (37.5%). All children received 1.5 times plasma volume plasmapheresis (mean 11 sessions, range 5-26), dialysis and immunosuppressive therapy. The mean duration of follow-up was 4 months (range 2-24 months) with a majority of the children (15/16, 93.75%) surviving acute illness. One child died of overwhelming sepsis and another was lost to follow-up. Of the survivors, eight had eGFR >60 mL/min/1.73 m(2), while eGFR was 15-60 mL/min/1.73 m(2) in the remaining six children. Eight children were still requiring antihypertensive medications and two were continuing peritoneal dialysis at the last follow-up. Thus early introduction of plasmapheresis along with other supportive therapy in immunological kidney disease may improve outcome.

Clinical presentation and long-term outcome of 144 patients with microscopic polyangiitis in a monocentric German cohort

OBJECTIVE

To evaluate the clinical presentation and long-term outcome of a vasculitis centre cohort of patients with microscopic polyangiitis (MPA) with respect to organ manifestations, treatment, chronic damage and mortality.

METHODS

We performed a retrospective chart review at our vasculitis referral centre. MPA patients admitted between 1991 and 2013 classified by a modified European Medicines Agency algorithm were diagnosed and treated according to a standardized interdisciplinary approach.

RESULTS

Comprehensive data from standardized interdisciplinary workups was available for 144 patients (median follow-up 72 months). The overall standardized mortality ratio was 1.40 (95% CI 0.91, 2.07; P = 0.13). We observed a higher mortality [hazard ratio (HR) 4.04 (95% CI 1.21, 13.45), P = 0.02] in 17 patients with MPA-associated fibrosing interstitial lung disease (ILD) and 56 patients with peripheral nervous system involvement [HR 5.26 (95% CI 1.10, 25.14), P = 0.04] at disease onset. One hundred and fifteen patients (79.9%) responded to the initial treatment. Sixty-one (42.3%) achieved complete remission and 54 (37.5%) achieved partial remission. Twenty (13.9%) showed a refractory disease course.

CONCLUSION

MPA patients at our tertiary rheumatology referral centre seemed to have a less severe phenotype resulting in a less severe disease course and better outcome than reported in other cohorts. Fibrosing ILD was significantly associated with mortality in this cohort.

[Prognosis and therapy of inflammatory rheumatic diseases : Impact of renal manifestations]

BACKGROUND

Inflammatory rheumatic diseases and their treatment cause various renal manifestations requiring modification of treatment.

OBJECTIVES

Discussion of renal manifestations in selected rheumatic diseases, including their impact on general prognosis and therapy.

MATERIALS AND METHODS

Basic literature and expert opinions are analyzed and discussed.

RESULTS

Inflammatory rheumatic diseases and their treatment cause various renal manifestations, including glomerular, tubular, interstitial, and vascular damage. The type of damage determines both, associated clinical symptoms (i.e. hematuria, proteinuria, loss of kidney function) and the renal and overall survival as will be discussed here for rheumatoid arthritis, systemic lupus erythematosus, scleroderma, Sjögrens syndrome, cryoglobulinemia and ANCA-associated vasculitis.

CONCLUSION

Renal manifestations are generally indicators of high disease activity and usually require more intensive treatment of the underlying rheumatic disease. Early and rigorous treatment, which has to be adapted to renal function, is capable of improving renal and overall survival in many of the affected patients.

Renal transplantation in anti-neutrophil cytoplasmic antibody-associated vasculitis

Despite major advances in the management of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) achieved in the last decades, a large proportion of AAV patients still develop end-stage renal disease. The survival of AAV patients dependent on dialysis is significantly worse compared with dialysis-independent AAV patients, but is comparable to other non-diabetic patients requiring dialysis. Renal transplantation (RTx) is the method of choice among renal replacement therapies and there has been increasing evidence that it is a suitable method with favorable patient- and graft-survival also in AAV patients. It is recommended to perform RTx after ≥12 months of remission, and ANCA positivity at the time of RTx is generally not considered a contraindication. Even though the risk of relapse after RTx is relatively low with current post-transplant immunosuppressive regimens, disease recurrence may occur. Besides cyclophosphamide, rituximab might become a therapeutic alternative for post-transplant AAV recurrence in the near future but its efficacy and safety in this setting needs to be confirmed in larger studies.

Comparison of phenotype and outcome in microscopic polyangiitis between Europe and Japan

OBJECTIVE

There are differences between Europe and Japan in the incidence and antineutrophil cytoplasmic antibody (ANCA) serotype of patients with microscopic polyangiitis (MPA). However, differences in phenotype or outcome have not been explored. We aimed to identify differences in phenotype and outcome of MPA between Europe and Japan.

METHODS

Sequential cohorts of patients with MPA and renal limited vasculitis were collected from European and Japanese centers (n = 147 and n = 312, respectively). Trial databases from the European Vasculitis Society and the Japanese patients with Myeloperoxidase (MPO)-ANCA-Associated Vasculitis (JMAAV) trial were studied (n = 254 and n = 48, respectively). We evaluated baseline characteristics including ANCA status and organ involvement, treatment, survival, and renal survival. Differences in survival and renal survival were studied using multivariate analysis.

RESULTS

The non-trial cohorts showed patients with MPA in Japan had a higher age at onset, more frequent MPO-ANCA positivity, lower serum creatinine, and more frequent interstitial pneumonitis than those in Europe (all p < 0.01). Comparisons between the trial databases demonstrated similar results. Cumulative patient survival and renal survival rates were not different between Europe and Japan (p = 0.71 and p = 0.38, respectively). Multivariate analysis identified age at onset, serum creatinine, gastrointestinal, and respiratory involvement as factors with higher risk of death. For endstage renal failure, serum creatinine and use of plasma exchange were identified as factors with higher risk, and immunosuppressant use as lower risk factors.

CONCLUSION

Phenotypes in patients with MPA were different between Europe and Japan. However, the outcomes of patient survival and renal survival were similar.

Retrospective analysis of factors predicting end-stage renal failure or death in patients with microscopic polyangiitis with mainly renal involvement

BACKGROUND

The aim of this study was to identify risk factors for end-stage renal failure (ESRF) or death in Japanese patients with microscopic polyangiitis (MPA) with renal involvement.

METHODS

From 54 consecutive patients with systemic vasculitis based on Watt's algorithm, we retrospectively analyzed 39 MPA patients with renal involvement, including 19 (48.7 %) with renal-limited vasculitis.

RESULTS

Thirty-three of 39 patients (84.6 %) demonstrated rapidly progressive glomerulonephritis, and 13 (33.3 %) developed ESRF; 8 of 13 required dialysis within 1 week. Thirteen (33.3 %) died during follow-up of more than 12 months, and 7 died during the first 6 months, mainly because of opportunistic infections. Overall survival at 6 and 12 months was 79.5 and 71.1 %, respectively. Serum creatinine levels did not differ significantly between survivors and non-survivors (P = 0.092). The mean Birmingham Vasculitis Activity Score, version 3 (BVAS v.3), was 16.2 ± 6.5, with a renal subscore of over 12 points in 82.1 %, and BVAS v.3 was marginally higher in non-survivors than survivors (P = 0.045). An age- and sex-adjusted Cox proportional hazards analysis demonstrated that neither the serum creatinine level (P = 0.277) nor BVAS v.3 (P = 0.188) at initial diagnosis was a risk factor for overall survival. The baseline serum creatinine cutoff value for discriminating between ESRF and non-ESRF was 4.6 mg/dl, with a sensitivity and specificity of 92.3 and 84.6 %, respectively.

CONCLUSIONS

Survival rates do not relate to ESRF in MPA patients with mainly renal involvement. Although patients with ESRF required regular hemodialysis, longer survival can be achieved.

The immunodominant myeloperoxidase T-cell epitope induces local cell-mediated injury in antimyeloperoxidase glomerulonephritis

Microscopic polyangiitis is an autoimmune small-vessel vasculitis that often manifests as focal and necrotizing glomerulonephritis and renal failure. Antineutrophil cytoplasmic Abs (ANCAs) specific for myeloperoxidase (MPO) play a role in this disease, but the role of autoreactive MPO-specific CD4(+) T cells is uncertain. By screening overlapping peptides of 20 amino acids spanning the MPO molecule, we identified an immunodominant MPO CD4(+) T-cell epitope (MPO(409-428)). Immunizing C57BL/6 mice with MPO(409-428) induced focal necrotizing glomerulonephritis similar to that seen after whole MPO immunization, when MPO was deposited in glomeruli. Transfer of an MPO(409-428)-specific CD4(+) T-cell clone to Rag1(-/-) mice induced focal necrotizing glomerulonephritis when glomerular MPO deposition was induced either by passive transfer of MPO-ANCA and LPS or by planting MPO(409-428) conjugated to a murine antiglomerular basement membrane mAb. MPO(409-428) also induced biologically active anti-MPO Abs in mice. The MPO(409-428) epitope has a minimum immunogenic core region of 11 amino acids, MPO(415-426), with several critical residues. ANCA-activated neutrophils not only induce injury but lodged the autoantigen MPO in glomeruli, allowing autoreactive anti-MPO CD4(+) cells to induce delayed type hypersensitivity-like necrotizing glomerular lesions. These studies identify an immunodominant MPO T-cell epitope and redefine how effector responses can induce injury in MPO-ANCA-associated microscopic polyangiitis.