Clinical features and outcome of microscopic polyangiitis under a new consensus algorithm of ANCA-associated vasculitides in Korea

Thoracic Manifestations of ANCA-associated Vasculitis: Review of the 2022 American College of Rheumatology-European Alliance of Associations of Rheumatology Classification Criteria

Antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) is a rare disease that manifests as necrotizing vasculitis involving small vessels without immune complex deposition. Granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA), and microscopic polyangiitis (MPA) are included in this disease entity. Diagnosis and differentiation of AAV is challenging because of the diverse and overlapping clinical manifestations and lack of pathognomonic findings. Therefore, AAV classification criteria have been developed to increase the likelihood of diagnosis using multidisciplinary approaches, including clinical, radiologic, laboratory, and pathologic findings. The new American College of Rheumatology and European Alliance of Associations for Rheumatology classification criteria were released in 2022 to classify AAVs using weighted criteria and threshold scores. They are expected to make the classification of GPA, EGPA, and MPA more accurate in the setting of suspected small-vessel vasculitis. The criteria present key thoracic imaging discriminators of GPA as "pulmonary nodules, masses, or cavitation" and MPA as "interstitial fibrosis," whereas, radiologic criteria of EGPA are not present. ANCA positivity and eosinophil count are included as key laboratory discriminators. It is essential for radiologists to familiarize themselves with imaging findings of each AAV and know the key imaging discriminators to aid in the differential diagnosis of AAVs. By reviewing the radiologic findings of thoracic manifestations of each AAV and applying the new criteria in a series of cases, the authors aim to provide a practical and stepwise approach to AAV for radiologists. ©RSNA, 2025 Supplemental material is available for this article.

Prediction model for respiratory-related mortality in microscopic polyangiitis with interstitial lung disease: multicentre REVEAL cohort study

OBJECTIVE

This study aimed to establish prediction models for respiratory-related mortality in microscopic polyangiitis (MPA) complicated by interstitial lung disease (ILD) using clinical characteristics.

METHODS

We enrolled patients with MPA with ILD between May 2005 and June 2021 in a multicentre cohort of Japanese patients with MPA (REVEAL cohort). We evaluated the demographic, clinical, laboratory, radiological findings, treatments and the presence of honeycombing 1 cm above the diaphragm using chest high-resolution CT (HRCT) on admission. We explored the risk factors predictive of respiratory-related mortality.

RESULTS

Of 115 patients, 26 cases died of respiratory-related diseases during a median follow-up of 3.8 years. Eighteen patients (69%) died due to respiratory infection, three (12%) had diffuse alveolar haemorrhage, and five (19%) had exacerbation of ILD. In univariate analysis, older age, lower percent forced vital capacity (%FVC), lower percent diffusing capacity of carbon monoxide (%DLCO), and the presence of honeycombing in the right lower lobe were identified as risk factors. Additionally, in multivariate analysis adjusted for age and treatment, %FVC, %DLCO and the presence of honeycombing in the right lower lobe were independently associated with respiratory-related mortality. We created prediction models based on the values of %FVC, %DLCO and presence of honeycombing on chest HRCT (termed "MPF model"). The 5-year respiratory-related death-free rate was significantly different between patients with MPA with ILD stratified by the number of risk factors based on the MPF model.

CONCLUSIONS

Our study indicates that the MPF model may help predict respiratory-related death in patients with MPA with ILD.

HRCT imaging of pulmonary involvement in granulomatosis with polyangiitis and microscopic polyangiitis at disease onset and during follow-up

BACKGROUND

The pulmonary involvement in patients with microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) is well known at disease onset but data during follow-up (after the induction regimen and when the first relapse occurs) are limited. Our goal was to analyze chest high-resolution computed tomography (HRCT) findings of (ANCA)-associated vasculitis patients.

METHOD

All consecutive unselected AAV patients over eighteen with positive ANCA status and with HRCT chest performed at the diagnosis were retrospectively enrolled between 2004 and 2019 at the Toulouse University Hospital (France). Two experienced pulmonologists and one expert respiratory radiologist reviewed independently HRCT chest scans.

RESULTS

A total of 157 AAV patients were included in the study. Two-thirds of AAV patients had pulmonary involvement at diagnosis. Diffuse alveolar hemorrhage (DAH) was observed in 31.2 % of cases, nodules and masses in 18.5 %, bronchial airway involvement in 13.4 %, and interstitial involvement in 12.7 %. Following the induction regimen, chest HRCT scans over a two-year period demonstrated significant improvement in DAH and nodular manifestations, whereas bronchial airway involvement exhibited variability and half of cases of interstitial lung disease (ILD) had progressive course. Outcomes and survival rates are better for nodular and bronchial involvement. DAH was the most frequent cause of deaths. Progressive fibrotic changes in ILD over time could impact prognosis despite AAV remission.

CONCLUSION

Employing a pattern-based approach with HRCT chest scans to assess lung involvement could be valuable in predicting treatment response, relapse, mortality, and could improved the management of AAV patients.

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.

Changing Phenotypes and Clinical Outcomes Over Time in Microscopic Polyangiitis

Introduction

Diagnosis and management of microscopic polyangiitis (MPA) have evolved considerably over the past decades, but it is unknown whether clinical and histological presentation and patient and renal outcomes have changed accordingly.

Methods

We compared clinical and histopathological characteristic at diagnosis, risk of death, end-stage kidney disease (ESKD), and relapse rate in patients diagnosed with MPA between 1980 and 2022, after grouping them in 2 periods (p): p1980-2001 and p2002-2022. We compared the mortality rate between the 2 periods using Kaplan-Meier estimator and Cox-regression, and competing risks of ESKD and death using the Aalen-Johansen estimator, Fine-Gray multiple regression, and multistate models.

Results

Out of 187 patients, 77 were in p1980-2001 and 110 in p2002 to 2022. Patients in p2002 to 2022 were older (66.2 ± 14.0 SD vs. 57.7 ± 15.8; P < 0.001), had a better kidney function (estimated glomerular filtration rate [eGFR] 25.9 ± 24.8 vs. 21.5 ± 28.2 ml/min per 1.73 m2; P = 0.011) and a lower prevalence of the Berden sclerotic class (5.9 vs. 20.9%; P = 0.011). Despite a similar crude and adjusted patient survival, the risk of ESKD decreased during p2002 to 2022 (subdistribution hazard ratio [HR] 0.30, 95% confidence interval [CI]: 0.16-0.57; P < 0.001). The results remained significant after accounting for death after ESKD and after adjusting for potential confounders (HR 0.33 [95% CI: 0.18-0.63; P < 0.001]). The risk of relapse was numerically higher during p2002 to 2022 (subdistribution-HR 1.64 [95% CI: 0.95-2.83; P = 0.075]).

Conclusion

MPA kidney involvement has become less severe over the past decades, leading to a reduced risk of ESKD and a higher relapse rate, despite a comparable risk of death.

Role of bronchoscopy for respiratory involvement in granulomatosis with polyangiitis and microscopic polyangiitis

Objectives

This study describes data from bronchoscopy performed at the diagnosis of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).

Methods

We conducted a retrospective study between 2004 and 2019 in patients aged >18 years with a diagnosis of microscopic polyangiitis (MPA) or granulomatosis with polyangiitis (GPA) who underwent bronchoscopy at onset of the disease. We collected bronchoalveolar lavage (BAL) and histological findings obtained during bronchoscopy.

Results

274 patients with AAV were identified. Among 92 bronchoscopies, 62 were performed at diagnosis, and 58 procedures were finally analysed. Cough was more frequent in patients with MPA than GPA (p=0.02). The presence of endobronchial lesions (24.1%) was found to be significantly associated with GPA (p<0.0001) and proteinase 3-ANCA (p=0.01). The most frequent endobronchial lesions were inflammation and hyperaemia of the bronchial mucosa (50%), followed by stenoses (28%), ulcerations (21%) and mass-like granulomatosis (7%). The diagnostic yield of bronchial biopsies was useful for visible lesions (66.6% versus 0%; p=0.006). On BAL, diffuse alveolar haemorrhage (DAH) was detected in 31 (53.4%) patients and was more frequent in MPA patients (70.4% versus 38.7%; p=0.016). In 16.1% of DAH cases, BAL confirmed the diagnosis despite the absence of clinical or biological arguments. The incidence of microbial infections on BAL (38%) was similar between MPA and GPA (p=0.54).

Conclusion

Bronchoscopy is an informative procedure at the onset of AAV disease in patients with respiratory manifestations. Endobronchial lesions are more frequently found in GPA and should be biopsied. BAL can be used to confirm DAH or diagnose superadded infection.

Interstitial Lung Disease in ANCA-Associated Vasculitis: Pathogenic Considerations and Impact for Patients' Outcomes

PURPOSE OF REVIEW

This review provides an update on recent advances in the diagnosis, pathogenesis, clinical presentation, histopathological findings, and treatment approaches for antineutrophil cytoplasmic antibody (ANCA) vasculitis-associated interstitial lung disease (AAV-ILD) with a focus on literature published in the last 3 years.

RECENT FINDINGS

Although there is no validated definition of AAV-ILD, which contributes to some of the heterogeneity seen in study results, there has been an increasing number of publications in recent years on this topic. Most patients with AAV-ILD have MPO-ANCA vasculitis, and this association appears to reduce their 5-year-survival to 60-66% (Sun et al. BMC Pulm Med 21(1), 2021, Maillet et al. J Autoimmun 106, 2020). Median age of diagnosis ranges from mid-60 s to mid-70 s (Ando et al. Respir Med 107(4), 2013), Kagiyama et al. BMJ Open Respir Res 2(1):1-9, 2015, Hozumi et al. Lung 194(2):235-42, 2016, Liu et al. Chest 156(4):715-23, 2019, Maillet et al. J Autoimmun 106, 2020, Wurmann et al. Sarcoidosis Vasc Diffuse Lung Dis 37(1):37-42, 2020, Watanabe et al. BMC Pulm Med 19(1), 2019). Computed tomography (CT) chest imaging for patients with AAV-ILD often shows a usual interstitial pneumonia (UIP) or nonspecific interstitial pneumonia (NSIP) pattern (12-58% and 13-61%, respectively) (Sun et al. BMC Pulm Med 21(1), 2021, Maillet et al. J Autoimmun 106, 2020, Wurmann et al. Sarcoidosis Vasc Diffuse Lung Dis 37(1):37-42, 2020, Watanabe et al. BMC Pulm Med 19(1), 2019, Baqir at al. Sarcoidosis Vasc Diffuse Lung Dis Off J WASOG 36(3):195-201, 2019). Additionally, lung biopsies typically do not demonstrate active inflammation, or capillaritis, questioning whether these patients should be treated with either immunotherapy or anti-fibrotic therapy, or both (Hozumi et al. Lung 194(2):235-42, 2016, Liu et al. Chest 156(4):715-23, 2019, Kitching at al. Nat Rev Dis Prim 6(1):71, 2020, Tanaka et al. Respir Med 106(12):1765-70, 2012). Besides immunosuppressive treatments, recent advances in anti-fibrotic therapy may offer patients with progressive AAV-ILD an alternative and/or more effective and individualized treatment option.

Antineutrophil cytoplasmic antibody-associated interstitial lung disease: a review

Over the past three decades, an increasing number of publications have reported the association between interstitial lung disease (ILD) and anti-neutrophil cytoplasmic antibody (ANCA) or ANCA-associated vasculitis (AAV). With this increased awareness, we have reviewed the literature to date and provide an update in this narrative review. The vast majority of cases of ILD have been shown to be in the setting of positive anti-myeloperoxidase antibody and can be present in up to 45% of patients of microscopic polyangiitis, though cases of ILD associated with proteinase 3 ANCA have rarely been reported. Pulmonary fibrosis and ANCA positivity can occur with or without systemic involvement. The pathogenetic mechanisms establishing the relationship between ANCA and the development of pulmonary fibrosis remain unclear. Histologic and radiographic features of ANCA-ILD most commonly reveal usual interstitial pneumonia or non-specific interstitial pneumonia patterns, though other atypical features such as bronchiolitis have been described. ILD in the setting of AAV has been associated with worse outcomes, and thus early identification and treatment in these patients is appropriate. We advocate that ANCA antibody testing be performed as a baseline evaluation in patients presenting with idiopathic interstitial pneumonia. Suggested treatment of ANCA-ILD includes immunosuppression and/or antifibrotic agents, though supporting data and clinical trials to substantiate use of these therapies are needed.

Survival in ANCA-Associated Vasculitides in a Peruvian Center: 28 Years of Experience

AIM

The aim of this study was to identify demographic and clinical risk factors for mortality in patients with antineutrophil cytoplasmic antibodies-associated vasculitides (AAVs) in a Peruvian tertiary referral hospital.

METHODS

Medical records of patients with AAV according to classification criteria or diagnosed by an experienced rheumatologist, covering the period between January 1990 and December 2018, were reviewed. Granulomatosis with polyangiitis, microscopic polyangiitis, eosinophilic granulomatosis with polyangiitis, and renal-limited vasculitis were included. Potential predictors of mortality were demographic factors, clinical manifestations, antineutrophil cytoplasmic antibodies status, diagnosis, disease categorization, the 2009 Five Factor Score (FFS), and treatment. Cox regression models were used to determine the risk factors for mortality. Univariable and multivariable analyses using a backward selection method were performed.

RESULTS

One hundred ninety-six patients were included; female-to-male ratio was 2:1. The median (interquartile range) age at diagnosis and follow-up were 60.0 (51.0-68.0) and 4.8 (1.3-11.6) years, respectively. One hundred forty-eight patients (75.5%) had microscopic polyangiitis, 37 (18.9%) granulomatosis with polyangiitis, 5 (2.6%) eosinophilic granulomatosis with polyangiitis, and 6 (3.0%) renal-limited vasculitis. Overall survival rates at 1, 5, and 10 years were 83.4%, 68.2%, and 51.7%, respectively. Ocular involvement was protective (hazards ratio [HR], 0.36; 95% confidence interval [CI], 0.17-0.74; p = 0.006), whereas renal (HR, 2.09; 95% CI, 1.33-3.28; p = 0.001) and lung involvement (HR, 2.07; 95% CI, 1.31-3.28; p = 0.002) and the 2009 FFSs were predictive of mortality (2009 FFS = 1: HR, 2.46; 95% CI, 1.50-4.04; p < 0.001; 2009 FFS = 2: HR, 3.07; 95% CI, 1.54-6.10; p = 0.001; 2009 FFS = 3: HR, 13.29; 95% CI, 3.69-47.88; p < 0.001).

CONCLUSIONS

Ocular involvement was protective, whereas 2009 FFS ≥ 1 and renal and lung involvement were predictive factors of mortality in Peruvian AAV patients.

Interstitial Lung Disease and Diffuse Alveolar Hemorrhage, the Two Key Pulmonary Manifestations in Microscopic Polyangiitis

Microscopic polyangiitis (MPA) is an antineutrophil cytoplasmic antibody (ANCA)‒associated necrotizing vasculitis, which mainly affects small vessels in various organs, especially the lungs. The two key pulmonary manifestations, interstitial lung disease (ILD) and diffuse alveolar hemorrhage (DAH), increase the morbidity and death rate of patients with MPA. ILD is more common in MPA than in other ANCA-associated vasculitis subsets and is primarily associated with myeloperoxidase-ANCA. Unlike alveolar hemorrhage due to pulmonary capillaritis, ILD can initially manifest as isolated pulmonary fibrosis. Of note, its most frequent radiographic pattern is the usual interstitial pneumonia pattern, similar to the characteristic pattern seen in idiopathic pulmonary fibrosis. In this review we present the pathogenesis, clinical manifestations, and radiographic and histopathologic features of ILD and DAH in MPA. We also briefly summarize the outcome and therapeutic options for the two conditions.

Impact of interstitial lung disease on mortality in ANCA-associated vasculitis: A systematic literature review and meta-analysis

Several retrospectivee described the association of interstitial lung disease (ILD) and ANCA-associated vasculitis (AAV). However, the relationship between the ILD and mortality in AAV patients have not been established so far. This study aims to estimate the relevance of AAV-associated-ILD (AAV-ILD) and mortality risk by conducting a systematic review and meta-analysis.A comprehensive systematic review was conducted in accordance with the guidelines of PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses). PubMed, Embase.com and the Cochrane Library (Wiley) were searched for original observational studies. Summary estimates were derived with a random-effects model and reported as risk ratio (RR), tested for publication bias and heterogeneity. Ten retrospective cohort studies were included, comprising 526 AAV-ILD patients enrolled from 1974 to 2018. Meta-analysis yielded a pooled RR of 2.90 (95% confidence interval 1.77–4.74) for death among those with AAV-ILD compared to control group. UIP pattern was associated with an even poorer prognosis in comparison to non-UIP pattern (RR 4.36, 95% confidence interval 1.14–16.78). Sensitivity analysis suggested that the meta-RR result was not skewed by a single dominant study. ILD might be associated with a higher mortality risk in AAV patients.

Interstitial lung disease and microscopic polyangiitis in chilean patients

Objective:

To describe the clinical and serological patients characteristics with Microscopic Polyangiitis (MPA) and Interstitial lung disease (ILD).

Methods:

Of all the patients with AAV diagnosed between 2007-2017 at the Hospital Clinico Universidad de Chile, those with MPA and ILD were selected and studied retrospectively.

Results:

All patients were Hispanic; median age at diagnosis 65 years (32-84). 59% were female. All were positive for p-ANCA, 16 patients for MPO. Most common manifestations were constitutional symptoms, weight loss and fever. CT-Scans patterns were Usual Interstitial Pneumonia (UIP) in 10 patients, Nonspecific Interstitial Pneumonia (NSIP) in 6 and fibrosis not UIP or NSIP pattern in 1. In 6 cases, ILD was diagnosed 0.5-14 years before MPA and concomitantly in 11.

Conclusions:

Although infrequent, Microscopic Polyangiitis should be suspected in patients with ILD particularly if extra-pulmonary manifestations that rise the possibility of a systemic illness are present, regardless of the time elapsed between the latter and the diagnosis of this type of lung involvement. (Sarcoidosis Vasc Diffuse Lung Dis 2020; 37 (1): 37-42)

Clinical characteristics and outcomes in microscopic polyangiitis patients with renal involvement: a study of 124 Chinese patients

BACKGROUND

Microscopic polyangiitis (MPA) is a systemic autoimmune disease, and renal involvement is frequently present in MPA. MPA patients with renal involvement may have a worse prognosis. In this study, we aimed to evaluate the prognostic factors associated with all-cause death and renal survival in MPA patients with renal involvement.

METHODS

A retrospective observational cohort study was performed. One hundred twenty-four patients newly diagnosed with MPA with renal involvement excluding end-stage renal disease (ESRD) who were hospitalized at the First Affiliated Hospital of Chongqing Medical University from January 2012 to July 2017 were included. All the survivors were followed up with until July 2018. The clinical and laboratory data at the time of the initial MPA diagnosis were collected, and the predictive values of the variables for mortality and renal outcome were analysed.

RESULTS

Among the 124 patients, 52 were men (41.9%) and 72 were women (58.1%), and the age range was from 25 to 85 years (63.9±10.6 years). Seventy-six patients (61.3%) had pulmonary involvement. Multivariate Cox analysis revealed that age≥65 years (HR: 2.437; P=0.021), serum creatinine≥500 μmol/L (HR=2.207; P=0.009) and interstitial lung disease (ILD) (HR=2.366; P=0.013) were associated with mortality. Cox multivariate analysis identified that serum creatinine≥500 μmol/L (HR=8.236; P<0.001) and ILD (HR=2.649; P=0.001) were independent detrimental factors for renal survival, and immunosuppressive treatment was a protective factor for renal survival (HR=0.349; P=0.001). The area under the ROC curve (AUC) of the serum creatinine level at diagnosis was 0.705 for mortality and 0.870 for progression to ESRD or the doubling of serum creatinine.

CONCLUSIONS

Age, serum creatinine level at diagnosis and ILD were independent predictors of mortality in MPA patients with renal involvement. Serum creatinine level at diagnosis, ILD and immunosuppressive treatment were independently related to renal survival.

Overview of the Vasculitides

The systemic vasculitides are heterogeneous clinicopathologic disorders that share the common feature of vascular inflammation. The resulting disorder can vary depending on involvement of specific organs, caliber of blood vessels, the underlying inflammatory process, and individual host factors. The cumulative result is diminished blood flow, vascular alterations, and eventual occlusion with variable ischemia, necrosis, and tissue damage. An international revised nomenclature system provides the necessary nosology and findings relevant to classify each of the vasculitides. This article is an introduction and overview of the clinical presentation, differential diagnosis, laboratory evaluation, and treatment of systemic and nervous system vasculitides.

Stroke due to Vasculitis in Children and Adults

The vasculitides are diseases characterized by inflammation of blood vessels and inflammatory leukocytes in vessel walls. There is an increased propensity for ischemic stroke, resulting from compromise of vessel lumina with distal tissue ischemia; and hemorrhagic or nonhemorrhagic stroke, and aneurysmal formation and bleeding, due to loss of vessel integrity.

Antineutrophil Cytoplasmic Antibody-Associated Vasculitis in Korea: A Narrative Review

Antineutrophil cytoplasmic antibody-associated vasculitis (AAV) is a group of systemic necrotising vasculitides, which often involve small vessels, and which lead to few or no immune deposits in affected organs. According to clinical manifestations and pathological features, AAV is classified into three variants: microscopic polyangiitis, granulomatosis with polyangiitis (GPA), and eosinophilic GPA. The American College of Rheumatology 1990 criteria contributed to the classification of AAV, although currently the algorithm suggested by the European Medicines Agency in 2007 and the Chapel Hill Consensus Conference Nomenclature of Vasculitides proposed in 2012 have encouraged physicians to classify AAV patients properly. So far, there have been noticeable advancements in studies on the pathophysiology of AAV and the classification criteria for AAV in Western countries. However, studies analysing clinical features of Korean patients with AAV have only been conducted and reported since 2000. One year-, 5 year-, and 10 year-cumulative patient survival rates are reported as 96.1, 94.8, and 92.8%. Furthermore, initial vasculitis activity, prognostic factor score, age and specific organ-involvement have been found to be associated with either all-cause mortality or poor disease course. The rate of serious infection is 28.6%, and 1 year-, 5 year- and 10 year-cumulative hospitalised infection free survival rates range from 85.1% to 72.7%. The overall standardised incidence ratio of cancer in AAV patients was deemed 1.43 compared to the general Korean population.

ANCA-Associated Vasculitis Pathogenesis: A Commentary

PURPOSE OF REVIEW

The ANCA-associated vasculitides are a group of small vessel vasculitides characterized by autoantibodies recognizing the neutrophil cytoplasmic antigens PR3 and MPO. We examine the current clinical and molecular immunology understanding of ANCA-associated vasculitides and discuss the current needs in our understanding of the pathogenic mechanisms of these rare diseases.

RECENT FINDINGS

The majority of efforts to understand the pathogenesis of these diseases have focused on dissecting neutrophil biology because the neutrophil is the primary expressor of ANCA autoantigens. However, a number of important genetic, clinical, and cellular biology observations suggest that attempts to understand the pathogenesis of ANCA vasculitides should move away from emphasis on the role of the neutrophil and instead re-focus on the potential role of other immune cell mediators. Whether or not neutrophils are the key determinant of ANCA-associated vasculitis pathogenesis should be revisited in detail. A neutrophil-centric view of the pathogenesis of these diseases cannot fully account for important genetic, clinical, and cellular biology observations that implicate important and under-appreciated roles for monocytes and T cells. Refocusing on these findings will likely lead to new discovery of novel therapeutic targets and the identification of clinically useful biomarkers for disease activity.

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.

Comparing Presenting Clinical Features in 48 Children With Microscopic Polyangiitis to 183 Children Who Have Granulomatosis With Polyangiitis (Wegener's): An ARChiVe Cohort Study

OBJECTIVE

To uniquely classify children with microscopic polyangiitis (MPA), to describe their demographic characteristics, presenting clinical features, and initial treatments in comparison to patients with granulomatosis with polyangiitis (Wegener's) (GPA).

METHODS

The European Medicines Agency (EMA) classification algorithm was applied by computation to categorical data from patients recruited to the ARChiVe (A Registry for Childhood Vasculitis: e-entry) cohort, with the data censored to November 2015. The EMA algorithm was used to uniquely distinguish children with MPA from children with GPA, whose diagnoses had been classified according to both adult- and pediatric-specific criteria. Descriptive statistics were used for comparisons.

RESULTS

In total, 231 of 440 patients (64% female) fulfilled the classification criteria for either MPA (n = 48) or GPA (n = 183). The median time to diagnosis was 1.6 months in the MPA group and 2.1 months in the GPA group (ranging to 39 and 73 months, respectively). Patients with MPA were significantly younger than those with GPA (median age 11 years versus 14 years). Constitutional features were equally common between the groups. In patients with MPA compared to those with GPA, pulmonary manifestations were less frequent (44% versus 74%) and less severe (primarily, hemorrhage, requirement for supplemental oxygen, and pulmonary failure). Renal pathologic features were frequently found in both groups (75% of patients with MPA versus 83% of patients with GPA) but tended toward greater severity in those with MPA (primarily, nephrotic-range proteinuria, requirement for dialysis, and end-stage renal disease). Airway/eye involvement was absent among patients with MPA, because these GPA-defining features preclude a diagnosis of MPA within the EMA algorithm. Similar proportions of patients with MPA and those with GPA received combination therapy with corticosteroids plus cyclophosphamide (69% and 78%, respectively) or both drugs in combination with plasmapheresis (19% and 22%, respectively). Other treatments administered, ranging in decreasing frequency from 13% to 3%, were rituximab, methotrexate, azathioprine, and mycophenolate mofetil.

CONCLUSION

Younger age at disease onset and, perhaps, both gastrointestinal manifestations and more severe kidney disease seem to characterize the clinical profile in children with MPA compared to those with GPA. Delay in diagnosis suggests that recognition of these systemic vasculitides is suboptimal. Compared with adults, initial treatment regimens in children were comparable, but the complete reversal of female-to-male disease prevalence ratios is a provocative finding.

[Microscopic polyangiitis associated with antineutrophil cytoplasmic antibodies: clinical features]

AIM

To study the clinical features of early- and extended-stage microscopic polyangiitis (MPA) and its outcomes on the basis of a long-term follow-up in a rheumatologist's practice.

SUBJECTS AND METHODS

The clinical features of early- and extended-stage MPA were studied in detail and the premorbid background and possible precipitating factors were analyzed in 70 patients with MPA and the proven hyperproduction of antineutrophil cytoplasmic antibodies (anti-proteinase-3 (anti-PR3) antibodies in 55% and anti-myeloperoxidase (anti-MPO) antibodies in 45%) who had been followed up for more than a year.

RESULTS

There is evidence for the nosological unity of the two immunological types of MPA associated with anti-PR-3 or anti-MPO antibodies. MPA has been demonstrated to be an aggressive, polysyndromic disease prone to recurrences (52%), the typical manifestation of which is glomerulonephritis (94%) that is rapidly progressive in every four cases and accompanied by hemorrhagic alveolitis (69%) and involvement of other organs. ENT organs and lungs have been noted to be commonly involved in early-stage MPA, which was observed in 61% of the patients in the premorbid period, and to become the first manifestation of MPA (63%) concurrent with body temperature rises (64%), arthralgia or arthritis (41%). Respiratory tract involvement in MPA may be asymptomatic. Anti-PR-3-associated MPA may manifest itself more aggressively and in the first 2 years it is characterized by a poorer prognosis than of anti-MPO-associated MPA (survival rates, 82 and 94%, respectively; p = 0.04). With time, the differences were levelled off; recurrences in the patients with anti-PR-3 and anti-MPO develop equally frequently and proceed showing the similar clinical picture; the survival curves converge by age 3. Anti-MPO-associated MPA is characterized by the highest rate of lung involvement in the clinical phase of the disease (61%) and by a propensity to develop hemorrhagic alveolitis, diffuse interstitial (22%) or circumscribed pulmonary fibrosis in the outcome. CONCLUSION. The findings emphasize how important to diagnose MPA early and to prescribe long-term active treatment using the entire current arsenal of medications as soon as possible until severe injury to organs and systems develops. To specify regularities in the development of MPA may be of value for the better diagnosis of the disease and the further elaboration of optimal treatment policy.

Pulmonary involvements of anti-neutrophil cytoplasmic autoantibody-associated renal vasculitis in Japan

BACKGROUND

Pulmonary involvement is one of the hallmark lesions of anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) as well as rapidly progressive glomerulonephritis (RPGN). However, the pulmonary involvement of AAV patients seems to differ between Europe and Japan, as does the ANCA serotype.

METHODS

This retrospective and prospective multicenter cohort study collected the clinical data of the features and outcomes of 1772 RPGN patients treated from 1989 to 2007 in Japan. Based on this nationwide RPGN survey, we analyzed the cases of 1147 AAV patients.

RESULTS

We found that 52.3% of the AAV patients had pulmonary involvements: 15.4% of the AAV patients had alveolar hemorrhage (AH), 26.2% had interstitial lung disease (ILD), 2.8% had bronchial asthma, 2.4% had pulmonary granuloma and 12.8% had a chest X-ray abnormality without AH, ILD or pulmonary granuloma. Patient survival was significantly different among the following six groups: the 5-year survival rate was 41.5% in the patients with AH, 50.2% in those with ILD, 67.9% in those with bronchial asthma, 62.5% in those with pulmonary granuloma, 55.8% in those with chest X-ray abnormality and 73.3% in those without pulmonary involvement. AH was one of the predictors of 1- and 5-year mortality for patient survival in AAV, and ILD was added as one of the predictors of 5-year mortality.

CONCLUSION

In these AAV patients, not only AH but also ILD was frequently observed. AH was associated with the prognosis, but ILD was associated with the long-term prognosis of AAV.

Usual interstitial pneumonia following resolution of cavitated pulmonary masses in a patient with ANCA-associated vasculitis

A 72-year-old woman with slight pulmonary interstitial reticular markings was initially diagnosed with microscopic polyangiitis (MPA). Two years later, cavitated pulmonary masses appeared, and a biopsy specimen revealed granulomas. Granulomatosis with polyangiitis (GPA) was diagnosed. The masses resolved with treatment. Ten years later, the usual interstitial pneumonia (UIP) pattern appeared on chest computed tomography (CT). The diagnosis of lung toxicity from methotrexate (MTX) or cyclophosphamide (CYC) was precluded by the clinical course. Despite treatment with prednisolone (PSL), the UIP progressed. The change of pulmonary pathology from masses to UIP is rare in patients with GPA.

Histopathological classification of pauci-immune glomerulonephritis and its impact on outcome

Rapidly progressive renal failure is a common but severe feature of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. A histopathological classification for ANCA-associated pauci-immune glomerulonephritis was developed for prognostication of these patients. The present study aims to classify patients of pauci-immune glomerulonephritis according to this classification and its impact on outcome. Eighty-six subjects with pauci-immune glomerulonephritis between July 2006 and October 2012 were included in the study. Their renal biopsies were reviewed and classified into focal, crescentic, sclerotic and mixed class as per the new classification. The outcomes were analyzed after 6 months of treatment. Of the 86 subjects, 34 (39.53 %) were granulomatosis with polyangiitis, 36 (41.86 %) microscopic polyangiitis, 1 eosinophilic granulomatosis with polyangiitis, while the rest (17.44 %) were unclassifiable. Thirteen (15.5 %), 43 (51.2 %), 12 (14.3 %) and 16 (19 %) patients were classified as focal, crescentic, sclerotic and mixed class, respectively. The mean serum creatinine at baseline was 280.23, 659.46, 573.72 and 542.78 µmol/L in focal, crescentic, sclerotic and mixed class, respectively. The probability of improvement in renal functions at 6 months decreased from focal to crescentic to mixed to sclerotic class, while the probability of death was highest in the sclerotic class followed by the mixed class. This difference in outcome was maintained irrespective of the clinical diagnosis or the Birmingham Vasculitis Activity Score. Our study has shown that the histopathological classification can be used to predict the severity of renal dysfunction as well as the treatment outcomes in pauci-immune glomerulonephritis.

Classification and characteristics of Japanese patients with antineutrophil cytoplasmic antibody-associated vasculitis in a nationwide, prospective, inception cohort study

Introduction

We investigated the clinical and serological features of patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) in Japan using data from a nationwide, prospective, inception cohort study.

Methods

In total, 156 Japanese patients with newly diagnosed AAV were classified according to the European Medicines Agency (EMEA) algorithm with exploratory surrogate markers for AAV-related non-granulomatous pulmonary lesions, predefined as alveolar haemorrhage and interstitial lung disease (ILD), and their clinical and serological features were evaluated.

Results

Using the EMEA algorithm, we identified 14 patients (9.0%) with eosinophilic granulomatosis with polyangiitis (EGPA), 33 (21.2%) with granulomatosis with polyangiitis (GPA), 78 (50.0%) with microscopic polyangiitis and renal-limited vasculitis (MPA/RLV), and 31 (19.9%) with unclassifiable vasculitis. The average ages of patients with EGPA (male/female, 5/9), GPA (12/21), and MPA/RLV (35/43) and unclassifiable (9/22) were 58.0, 63.6, 71.1, and 70.6 years, respectively. Myeloperoxidase (MPO)-ANCA and proteinase-3 ANCA positivity was 50.0% and 0% for EGPA, 54.6% and 45.5% for GPA, 97.4% and 2.6% for MPA/RLV, and 93.5% and 3.2% for unclassifiable, respectively. According to the Birmingham Vasculitis Activity Score (BVAS), cutaneous (71.4%) and nervous system (92.9%) manifestations were prominent in EGPA and ear, nose, and throat manifestations (84.9%) and chest manifestations (66.7%) in GPA. Renal manifestations developed frequently in MPA/RLV (91.0%) and GPA (63.6%). The average serum creatinine levels were 0.71 mg/dL for EGPA, 1.51 mg/dL for GPA, 2.46 mg/dL for MPA/RLV, and 0.69 mg/dL for unclassifiable. The percentages of patients with ILD were 14.3% for EGPA, 9.0% for GPA, 47.4% for MPA/RLV, and 61.3% for unclassifiable. Patients with ILD (n = 61) had significantly lower BVAS (P = 0.019) with fewer ear, nose, and throat and cardiovascular manifestations than patients without ILD (n = 95).

Conclusions

MPO-ANCA-positive MPA/RLV is the most common form of AAV in Japanese patients, and one-half of patients with GPA were positive for MPO-ANCA. ILD is an important clinical manifestation in Japanese patients with AAV. Unclassifiable vasculitis with MPO-ANCA positivity and ILD may represent a novel variant of MPA.

Trial Registration

The University Hospital Medical Information Network Clinical Trials Registry: UMIN000001648. Registered 28 February 2009.

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.

ANCA-associated vasculitis: report from Korea

We investigated the clinical features of Korean patients with anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV) by reviewing the literature. The characteristics of AAV in Korean patients were as follows: (1) granulomatous and limited disease is prevalent in granulomatosis with polyangiitis (Wegener's) (GPA), (2) ANCA positivity is lower in GPA (56.6-68.9%) and eosinophilic granulomatosis with polyangiitis (EGPA) (5.9-8.3%), whereas it is higher in microscopic polyangiitis (MPA) (69-94%), (3) C-ANCA/proteinase 3 (PR3)-ANCA positivity is 71.5-100% in GPA and P-ANCA/myeloperoxidase (MPO)-ANCA positivity reached 94-100% in patients with MPA, (4) renal involvement or progression to end-stage renal disease was lower in Korean patients with GPA and EGPA than in Caucasians with GPA and EGPA (according to data provided in reports). The data provided here may need to be confirmed in large-scale studies.

Clinical outcomes of Japanese MPO-ANCA-related nephritis: significance of initial renal death for survival

OBJECTIVE

Anti-myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA)- related nephritis constitutes 60% of rapidly progressive glomerulonephritis (RPGN) in Japan. The reported 1-year survival rate is over 80%, however, the long-term prognosis remains unknown. We therefore investigated the prognosis and factors affecting the clinical course of patients.

METHODS

We retrospectively investigated 74 patients (female, n=42; median age, 73.0 years) with MPO-ANCA-related nephritis. The patients were admitted to Fukushima Medical University and two affiliated hospitals between 2000 and 2010.

RESULTS

Median estimated GFR (eGFR) was 12.1 mL/min/1.73 m2 at admission. The Birmingham Vasculitis Activity Score (BVAS version 3: max 63 points) at diagnosis and at 4 weeks after start of treatment were 15.0 and 5.0, respectively. Twenty-three patients (31%) died during a median observation period of 30.5 months. Sixteen patients (22%) presented with end-stage renal disease (ESRD) at the initial phase, and needed regular dialysis therapy. Multivariate Cox proportional hazards model analysis revealed that renal death at the initial phase was a significant risk factor for all-cause death (Hazard ratio, 5.72; 95% confidence interval, 2.49-13.09; p<0.001). Furthermore, BVAS>6, evaluated 4 weeks after start of treatment, is an independent risk factor for ESRD and patient survival.

CONCLUSION

This is the first investigation to demonstrate clinical features focusing on MPO-ANCA-related nephritis. Renal death at the initial phase of treatment is a powerful risk factor for all-cause death in patients with MPO-ANCA-related nephritis. Patients at high risk of death and ESRD could be stratified according to BVAS.