Prevalence and Responsiveness to Treatment of Lung Abnormalities on Chest Computed Tomography in Patients With Microscopic Polyangiitis: A Multicenter, Longitudinal, Retrospective Study of One Hundred Fifty Consecutive Hospital-Based Japanese Patients

Latent class analysis of chest CT abnormalities to define subphenotypes in patients with MPO-ANCA-positive microscopic polyangiitis

BACKGROUND

Patients with microscopic polyangiitis (MPA) and positive myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) may present with various abnormalities in chest computed tomography (CT). This study aimed to identify subphenotypes using latent class analysis (LCA) and to explore the relationship between the subphenotypes and clinical patterns, as well as compare the clinical characteristics of these subphenotypes in patients with MPO-ANCA-positive MPA (MPO-MPA).

METHODS

The study identified subphenotypes using LCA based on chest CT findings in 178 patients with MPO-MPA and pulmonary involvement from June 2014 to August 2022.

RESULTS

LCA identified 27 participants (15.2%) in class 1, 43 (24.1%) in class 2, 35 (19.7%) in class 3, and 73 (41.0%) in class 4. Class 1 was characterized by prominent inflammatory exudation, class 2 by fibrosis and architectural distortion, class 3 by predominantly bronchiectasis, and class 4 by lesions mixed with inflammation and fibrosis. Class 1 had the highest level of extrapulmonary disease activity, with 77.8% of patients experiencing diffuse alveolar hemorrhage. Class 2 had the lowest level of extrapulmonary disease activity, with 41.9% of patients showing usual interstitial pneumonia. Class 3 patients were more likely to have complications involving the ear, nose, and throat, as well as pulmonary infections before treatment, and they exhibited the best outcomes. The characteristics and outcomes of class 4 were intermediate among the four classes.

CONCLUSIONS

These findings suggest that bronchiectasis may represent a unique pattern of pulmonary involvement in MPO-MPA, highlighting the importance of screening for bronchiectasis in MPO-MPA and identifying optimal management strategies.

Clinical features and outcomes of small airway disease in ANCA-associated vasculitis

BACKGROUND AND OBJECTIVE

To clarify the prevalence, features and outcomes of small airway disease (SAD) in a Chinese cohort with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) related pulmonary involvement.

METHODS

SAD was recorded when the manifestations of either centrilobular nodules or air trapping were observed according to CT scans, except for infection or other airway-related comorbidities. Baseline and follow-up data were collected retrospectively.

RESULTS

Of the 359 newly diagnosed AAV patients with pulmonary involvement, 92 (25.6%) had SAD, including 79 (85.9%) cases of anti-MPO-ANCA positive, 9 (9.8%) cases of anti-PR3-ANCA positive and 2 (2.2%) cases of double positive. Patients with SAD were more likely to be younger, female, non-smokers, have more ear-nose-throat (ENT) involvement, and have higher baseline Birmingham Vasculitis Activity Score (BVAS) compared to patients without SAD. Several AAV-related SAD patients have improved lung function and CT scans after immunosuppressive therapy. Patients with SAD had a better prognosis compared to those without SAD. When dividing all patients into three groups: isolated SAD (only small airway involvements), SAD with other lower airway involvements, and non-SAD, patients in the SAD with other lower airway involvements group had the highest risk of infection, while patients in the non-SAD group had the worst long-term outcomes. Similar results were observed in anti-MPO-ANCA positive patients when performing subgroup analyses.

CONCLUSION

SAD is a unique manifestation of AAV-related lung involvement and exhibits distinct clinical features. It is vital to focus on SAD because of its association with prognosis and infection in AAV patients, especially in anti-MPO-ANCA positive patients. Moreover, SAD might represent a better response to immunosuppressors.

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.

Immune-mediated lung diseases: A narrative review

The role of immunity in the pathogenesis of various pulmonary diseases, particularly interstitial lung diseases (ILDs), is being increasingly appreciated as mechanistic discoveries advance our knowledge in the field. Immune-mediated lung diseases demonstrate clinical and immunological heterogeneity and can be etiologically categorized into connective tissue disease (CTD)-associated, exposure-related, idiopathic, and other miscellaneous lung diseases including sarcoidosis, and post-lung transplant ILD. The immunopathogenesis of many of these diseases remains poorly defined and possibly involves either immune dysregulation, abnormal healing, chronic inflammation, or a combination of these, often in a background of genetic susceptibility. The heterogeneity and complex immunopathogenesis of ILDs complicate management, and thus a collaborative treatment team should work toward an individualized approach to address the unique needs of each patient. Current management of immune-mediated lung diseases is challenging; the choice of therapy is etiology-driven and includes corticosteroids, immunomodulatory drugs such as methotrexate, cyclophosphamide and mycophenolate mofetil, rituximab, or other measures such as discontinuation or avoidance of the inciting agent in exposure-related ILDs. Antifibrotic therapy is approved for some of the ILDs (e.g., idiopathic pulmonary fibrosis) and is being investigated for many others and has shown promising preliminary results. A dire need for advances in the management of immune-mediated lung disease persists in the absence of standardized management guidelines.

Interstitial Lung Disease and Anti-Neutrophil Cytoplasmic Antibody–Associated Vasculitis

Interstitial lung disease is a common complication of anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). It is seen most commonly in microscopic polyangiitis owing to the pathogenic effect of myeloperoxidase in the lung. Oxidative stress, neutrophil elastase release, and expression of inflammatory proteins by neutrophil extracellular traps result in fibroblast proliferation and differentiation and therefore fibrosis. Usually, interstitial pneumonia pattern fibrosis is common and associated with poor survival. Treatment for patients with AAV and interstitial lung disease lacks evidence, and those with vasculitis are treated with immunosuppression, whereas those with progressive fibrosis may well benefit from antifibrotic therapy.

Changing patterns of pulmonary abnormalities in rheumatoid arthritis

BACKGROUND

As a first step in identifying the developmental pathways of pulmonary abnormalities in rheumatoid arthritis (RA), we sought to determine the existing and changing patterns of pulmonary abnormalities.

METHODS

We conducted a retrospective cohort study of consecutive patients with RA who underwent high-resolution computed tomography before and during biologic therapy. The presence of 20 pulmonary abnormalities and the changes in those abnormalities were recorded. Patterns of pre-existing and changing abnormalities were examined via cluster analysis, and their relationship was also assessed using the Kaplan-Meier method and log-rank test.

RESULTS

A total of 208 subjects were included. Pulmonary abnormalities were observed in 70% of patients: 39% had interstitial lung disease, and 55% had airway disease (AD). Several different pulmonary abnormalities were commonly found to co-exist in several patterns in the same patient. In most patients with pulmonary abnormalities, AD was present alone or in combination with other abnormalities. During the observation period (mean 3.2 years), 172 pulmonary abnormalities had changed in 91 patients: 115 pulmonary abnormalities newly emerged, whereas 42 worsened and 25 demonstrated improvement. Pulmonary abnormalities changed in several patterns. Correlations were observed between pre-existing and new/worsening abnormalities at individual and regional levels, such as new ground-glass opacity (GGO) and pre-existing AD, small nodular patterns, and honeycombing. AD was a possible initial abnormality.

CONCLUSIONS

Pulmonary abnormalities occurred and changed in several patterns, which suggests the existence of developmental pathways of pulmonary abnormalities. AD may play an important role in the development of these abnormalities, including GGO.

Bronchiectasis in patients with antineutrophil cytoplasmic antibody-associated vasculitis: a case control study on clinical features and prognosis

BACKGROUND

Bronchiectasis was reported in 2%-40% of patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV), but there were no studies on the prevalence, risk factors and impact of AAV-associated bronchiectasis in Chinese patients.

RESEARCH DESIGN AND METHODS

AAV patients were retrospectively enrolled. The clinical, laboratory and imaging features and the prognosis were analyzed and compared between those with and without bronchiectasis.

RESULTS

Bronchiectasis was present in 48/212 (22.6%) of our AAV patients, among whom 41 were confirmed in 210 patients (19.5%) who received chest HRCT at the initial diagnosis of AAV. There were more women and fewer smokers in those with bronchiectasis as compared to those without. Cases with positive anti-MPO were more likely to have bronchiectasis (26.2%), and those with bronchiectasis were more likely to be anti-MPO positive (93.8%). Patients who had a diagnosis of bronchiectasis before AAV were more likely to have nervous system involvement, while patients without bronchiectasis had higher 24h proteinuria. The presence of bronchiectasis showed no significant effect on the 1, 3, 5-year survival.

CONCLUSIONS

Nearly 20% of patients showed bronchiectasis on chest HRCT at the initial diagnosis of AAV, and positivity of anti-MPO was associated with bronchiectasis in a Chinese cohort of AAV patients.

Pulmonary involvement of ANCA-associated vasculitis in adult Chinese patients

Objective

The aim of this study was to clarify the clinical characteristics and long-term outcomes of ANCA-associated vasculitis (AAV) patients with pulmonary involvement from a single Chinese cohort.

Methods

Newly diagnosed AAV patients with pulmonary involvement, as defined by CT, were recruited from January 2010 to June 2020. Clinical data and CT images were collected retrospectively. Baseline CTs were evaluated and re-classified into four categories: interstitial lung disease (ILD), airway involvement (AI), alveolar hemorrhage (AH), and pulmonary granuloma (PG).

Results

A total of 719 patients were newly diagnosed with AAV, 366 (50.9%) of whom combined with pulmonary involvement at baseline. Among the AAV cases with pulmonary involvement, 55.7% (204/366) had ILD, 16.7% (61/366) had AI alone, 14.8% (54/366) had PG, and 12.8% (47/366) had AH alone. During follow-up of a median duration of 42.0 months, 66/366 (18.0%) patients died, mainly died from infections. Survival, relapse, and infection were all significantly different based on the radiological features. Specifically, the ILD group tends to have a poor long-term prognosis, the PG group is prone to relapse, and the AI group is apt to infection. The AH group has a high risk of both early infection and relapse, thus a poor short-term prognosis.

Conclusion

AAV patients with diverse radiological features have different clinical characteristics and outcomes. Therefore, the intensity of immunosuppressive therapy must be carefully valued by considering the baseline CT findings among AAV patients with pulmonary involvement.

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.

Pulmonary Vasculitides: A Radiological Review Emphasizing Parenchymal HRCT Features

Vasculitides represent a heterogeneous group of immune-mediated disorders, characterized by a systemic inflammatory destructive process of the blood vessels resulting either in ischemia or hemorrhage. The organ involved and vessel size influence the pattern of presentation of the pathology. The lung is commonly involved in systemic vasculitides, with heterogeneous clinical, radiological, and histopathological presentations. Primary vasculitides most commonly associated with lung parenchymal involvement include small-vessel antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides, such as granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA), and microscopic polyangiitis (MPA). Several studies have reported cases of interstitial lung diseases (ILDs) associated with systemic vasculitis, particularly those positive for ANCA associated vasculitis/vasculitidis: AAV. We have selected from our case series different radiological features of pulmonary vasculitis (i.e., solitary or multiple nodules, cavitary lesions, nodules with centrilobular or peribronchial distribution, airspace consolidations, “crazy paving” appearance, interstitial disease), including cases with interstitial lung alterations. Therefore, the aim of this review is to describe the typical clinical manifestations of vasculitides and their main radiologic features (especially AAV).

Interstitial Lung Disease in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis Patients: Comparison With Idiopathic Pulmonary Fibrosis

BACKGROUND/OBJECTIVE

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) may involve the kidney, respiratory tract, skin, or central and peripheral nervous system. Reports of interstitial lung disease (ILD) in AAV (AAV-ILD) have been increasing.

METHODS

We reviewed the medical records of all patients with AAV-ILD between January 1, 2007, and December 31, 2017, and compared their pulmonary involvement to patients with idiopathic pulmonary fibrosis (IPF).

RESULTS

We identified 24 patients with AAV-ILD: 14 with microscopic polyangiitis, 8 with granulomatosis with polyangiitis, and 2 with eosinophilic granulomatosis with polyangiitis. Perinuclear or myeloperoxidase ANCA was present in 16 cases (66.7%), whereas cytoplasmic or proteinase 3 ANCA was positive in 8 (33.3%). Usual interstitial pneumonia (UIP) was seen in 11 (45.8%), probable UIP in 1 (4.2%), indeterminate UIP in 2 (8.3%), and an alternate diagnosis in 10 (41.7%), and was further characterized as chronic hypersensitivity pneumonitis-like pattern seen in 6 (25%), nonspecific interstitial pneumonia-like pattern in 3 (12.5%), and cryptogenic organizing pneumonia-like pattern in 1 (4.2%). Forced vital capacity and diffusing capacity declined over time in patients with AAV-ILD. When compared with the IPF cohort, patients with AAV-ILD had intermediate survival and speed of lung function decline (3-year survival in AAV-ILD group was 94% vs 69% in IPF).

CONCLUSIONS

Antineutrophil cytoplasmic antibody-associated vasculitis ILD is a progressive and potentially fatal condition. Although most cases in the literature are associated with p-ANCA and positive myeloperoxidase, we found that a third of patients had c-ANCA or granulomatosis with polyangiitis. Our cohort adds experience in this rare manifestation of AAV.

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.

Clinical features and long-term outcomes of interstitial lung disease with anti-neutrophil cytoplasmic antibody

Background

Patients with interstitial lung disease (ILD) are occasionally positive for anti-neutrophil cytoplasmic antibodies (ANCAs). Differences between ILDs secondary to microscopic polyangiitis (MPA) and isolated ANCA-positive idiopathic interstitial pneumonia (IIP) remain unclear. The aim of this study was to explore the differences in clinical features and outcomes between MPA-associated ILDs and isolated ANCA-positive IIPs.

Methods

We reviewed 1338 ILDs patients with available ANCA results and retrospectively analysed 80 patients who were ANCA-positive. MPA-associated ILDs (MPA-ILDs group) and isolated ANCA-positive IIPs (ANCA-IIPs group) were compared.

Results

Among 80 patients with ANCA-positive ILDs, 31 (38.75%) had MPA-ILDs, and 49 (61.25%) had isolated ANCA-positive IIPs. Compared with ANCA-IIPs group, patients in MPA-ILDs group had a higher proportion of fever (p = 0.006) and higher neutrophil count (p = 0.011), erythrocyte sedimentation rate (ESR) (p < 0.001) and C-reactive protein (CRP) (p = 0.005). Multivariable analysis showed that ESR level was an independent risk factor for mortality in all 80 ANCA-positive ILDs patients (HR 1.028, p = 0.001). Survival in MPA-ILDs group was lower than that in ANCA-IIPs group, and further stratified analysis revealed that ANCA-IIPs patients with elevated ESR or CRP had a worse prognosis than those with normal inflammation markers, with 5-year cumulative survival rates of 60.00%, 86.90% and 100.00% in MPA-ILDs and ANCA-IIPs with and without elevated inflammation markers, respectively.

Conclusions

Among patients with ANCA-positive ILDs, the prognoses of ANCA-IIPs with normal inflammation markers, ANCA-IIPs with elevated inflammation markers and MPA-ILDs were sequentially poorer. Therefore, stratified treatment should be considered in the management of ILDs patients positive for ANCAs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01451-4.

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.

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 poor prognostic factors of respiratory related death in microscopic polyangiitis complicated by interstitial lung disease

The prognosis of microscopic polyangiitis (MPA) with interstitial lung disease (ILD) is significantly worse than that of MPA without ILD. However, the clinical characteristics in MPA-ILD, especially poor prognostic factors, are not elucidated. We evaluated demographic, clinical, laboratory, and radiological findings, treatments, and outcomes of 80 patients with MPA, and investigated prognostic factors of respiratory-related death in patients with myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA) positive MPA-ILD. Ground-glass opacity and fibrosis were evaluated as scores on high-resolution computed tomography (HRCT). The presence of ILD was consistent with a high risk of respiratory-related death (hazard ratio, 4.8; P = 0.04). Multivariable logistic regression analyses using propensity scoring showed right or left lower lobe fibrosis score to be significantly associated with respiratory-related death (P = 0.0005 and 0.0045, respectively). A right or left lower lobe fibrosis score ≥ 2, indicating the presence of honeycombing at 1 cm above the diaphragm, was determined to be the best cut-off value indicating a poor prognosis. The 5-year survival rate was significantly lower in patients with right or left lower lobe fibrosis score ≥ 2 (survival rates: 37% and 19%, respectively) than those with a score < 2 (71% and 68%, respectively) (P = 0.002 and 0.0007, respectively). These findings suggest that the presence of honeycomb lesions in bilateral lower lobes on chest HRCT was associated with respiratory-related death in patients with MPO-ANCA positive MPA-ILD.

Slowly progressive anti-neutrophil cytoplasmic antibody-associated renal vasculitis: clinico-pathological characterization and outcome

BACKGROUND

Although rapidly progressive glomerulonephritis is the main renal phenotype of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), slow renal disease progression is sometimes observed. These forms have been rarely discussed; we analysed their prevalence, clinico-pathological characteristics and outcome.

METHODS

We screened patients with microscopic  polyangiitis (MPA) and granulomatosis with polyangiitis followed at seven referral centres and selected those with estimated glomerular filtration rate (eGFR) reduction <50% over a 6-month period preceding diagnosis. Data regarding patient features and response to treatment were retrieved.

RESULTS

Of 856 patients, 41 (5%) had slowly progressive renal AAV. All had MPA and all but one was P-ANCA/myeloperoxidase (MPO) ANCA-positive. At diagnosis, the median age was 70 years [interquartile range (IQR) 64-78] and extra-renal manifestations were absent or subclinical (interstitial lung lesions in 10, 24%). The median (IQR) eGFR was 23 mL/min/1.73 m² (15-35); six patients (15%) had started renal replacement therapy (RRT). All had proteinuria (median 1180 mg/24 h, IQR 670-2600) and micro-haematuria. Main histologic findings were extracapillary proliferation at chronic stages and glomerulosclerosis; following Berden's classification, 6/28 biopsies (21%) were 'focal', 1/28 (4%) 'crescentic', 9/28 (32%) 'mixed' and 12/28 (43%) 'sclerotic'. At last follow-up (median 32 months, IQR 12-52), 20/34 patients (59%) treated with immunosuppression had eGFR improvement >25% as compared with diagnosis, while 4/34 (12%) had started RRT.

CONCLUSIONS

AAV may present with slow renal disease progression; this subset is hallmarked by advanced age at diagnosis, positive MPO-ANCA, subclinical interstitial lung lesions and chronic damage at kidney biopsy. Partial renal recovery may occur following immunosuppression.

Myeloperoxidase anti-neutrophil cytoplasmic antibody-associated vasculitis with a unique imaging presentation of organizing pneumonia: A case report

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) constitutes a group of blood vessel inflammation diseases of autoimmune origin. Myeloperoxidase (MPO) ANCA is closely related to ANCA associated AAV. The MPO-ANCA positive AAV patients have lung involvement at high rates; however, there are only a few reported cases with organizing pneumonia (OP). A 78-year-old man was presented to our hospital due to a fever of 38 °C despite a whole month of antibiotics treatment. Chest computed tomography image revealed restricted consolidations visible in the middle lobe of the right lung and the upper lobe of the left lung, which suggested an OP pattern. MPO-ANCA and urine occult blood tests were positive. Histopathological examination of the transbronchial biopsy revealed OP and mucus plug. Histological findings on renal biopsy showed necrotizing glomerulonephritis related to AAV. The patient was diagnosed with MPO-ANCA positive AAV and was treated with systemic corticosteroid therapy, from which he recovered rapidly. Thus, when diagnosing OP, the possibility of AAV should be considered by ordering patients’ serum ANCA and occult hematuria tests.

2020 international consensus on ANCA testing beyond systemic vasculitis

This document follows up on a 2017 revised international consensus on anti-neutrophil cytoplasm antibodies (ANCA) testing in granulomatosis with polyangiitis and microscopic polyangiitis and focuses on the clinical and diagnostic value of ANCA detection in patients with connective tissue diseases, idiopathic interstitial pneumonia, autoimmune liver diseases, inflammatory bowel diseases, anti-glomerular basement membrane (GBM) disease, infections, malignancy, and during drug treatment. Current evidence suggests that in certain settings beyond systemic vasculitis, ANCA may have clinical, pathogenic and/or diagnostic relevance. Antigen-specific ANCA targeting proteinase-3 and myeloperoxidase should be tested by solid phase immunoassays in any patient with clinical features suggesting ANCA-associated vasculitis and in all patients with anti-GBM disease, idiopathic interstitial pneumonia, and infective endocarditis associated with nephritis, whereas in patients with other aforementioned disorders routine ANCA testing is not recommended. Among patients with autoimmune liver diseases or inflammatory bowel diseases, ANCA testing may be justified in patients with suspected autoimmune hepatitis type 1 who do not have conventional autoantibodies or in case of diagnostic uncertainty to discriminate ulcerative colitis from Crohn's disease. In these cases, ANCA should be tested by indirect immunofluorescence as the target antigens are not yet well characterized. Many questions concerning the optimal use of ANCA testing in patients without ANCA-associated vasculitis remain to be answered.

Microscopic Polyangiitis with Pulmonary Fibrosis: An Often-Recognized Manifestation of the Disease

Background

Microscopic polyangiitis (MPA) can manifest with atypical features such as pulmonary fibrosis and chronic obstructive pulmonary disease (COPD), which are atypical and unusual features of small vessel vasculitis.

Case Presentation

This paper presents two patients with microscopic polyangiitis and respiratory symptoms attributable to atypical pulmonary manifestations. Pulmonary fibrosis was present in both cases, with COPD also present in one patient. Management involved methylprednisone, prednisone, and cyclophosphamide. The second patient also received azathioprine. Both patients responded well to immunosuppressive treatment; however, pulmonary fibrosis and COPD were refractory to immunosuppression.

Conclusion

Pulmonary manifestations including pulmonary fibrosis, emphysema, and bronchiectasis are observed in MPA. Evaluation of MPA in unexplained cases should be performed to avoid delays in diagnosis and management. Patients who present with MPA with pulmonary manifestations may respond to treatment, but their pulmonary features demonstrate a refractory nature to such management.

Diffuse alveolar haemorrhage associated with subsequent development of ANCA positivity and emphysema in three young adults

BACKGROUND

Diffuse alveolar haemorrhage (DAH) is characterized by the diffuse accumulation of red blood cells within the alveoli, presence of ground glass opacities and/or consolidation on computed tomography (CT). Aside from identifiable non-immune causes, DAH is classically subdivided into idiopathic (idiopathic pulmonary haemosiderosis, IPH) and autoimmune DAH. Here we describe three cases presenting with recurrent pulmonary haemorrhage, initially classified as IPH, who, several years after first presentation, develop anti myeloperoxidase antibodies (MPO) positivity, emphysema on CT and, in one case, renal involvement.

CASE PRESENTATION

Patient 1 was diagnosed with IPH aged 14. Her disease remained poorly controlled despite immunosuppression, although ANCA remained negative over the years. Nineteen years from initial presentation, she developed MPO-ANCA positive antibodies and mild renal impairment. She was treated with Rituximab with good response. From first presentation, the chest CT was consistently characterized by diffuse ground-glass opacities and interlobular septal thickening. Ten years later, cystic opacities consistent with emphysema, with a striking peribronchovascular distribution, developed. Patient 2 was diagnosed with IPH aged 32. He was treated with corticosteroids and methotrexate, with fluctuating response. At 11 years from initial presentation, MPO-ANCA positivity was identified, and emphysema with a peribronchovascular distribution was observed on CT, with subsequent significant increase in extent. Patient 3 was diagnosed with IPH at the age of seven, and had recurrent episodes of haemoptysis of varying degree of severity, treated with intermittent courses of corticosteroids until age 11, when he was intubated due to severe DAH. Eight years after the diagnosis emphysematous changes were noted on CT and MPO-ANCA positivity developed for the first time 11 years after initial diagnosis.

CONCLUSIONS

We believe these three cases highlight: 1) the possibility of development of ANCA positivity several years down the line from first DAH presentation 2) the possibility that DAH may lead to cystic/emphysematous changes with peribronchovascular distribution on CT. Moreover, the need for ongoing immunosuppressive treatment and the development of emphysema, emphasize a possible role played by autoimmune phenomena, even when DAH is initially diagnosed as "idiopathic". Further studies are required to better understand the relationship between DAH, ANCA positivity and development of emphysema.

The Association of Airway Comorbidities With the Clinical Phenotypes and Outcomes of Patients With Antineutrophil Cytoplasmic Autoantibody-associated Vasculitis

OBJECTIVE

We investigated the association of airway comorbidities with the clinical phenotypes and outcomes of myeloperoxidase (MPO)-antineutrophil cytoplasmic antibodies (ANCA)-positive ANCA-associated vasculitis (AAV).

METHODS

An AAV patient multicenter cohort trial was established in 13 hospitals in western Japan between 2012 and 2018. We examined 143 of the new-onset MPO-ANCA-positive AAV patients. Their clinical characteristics and comorbidities at disease onset were compared based on clinical phenotypes. Multivariate analysis was performed to identify factors predictive of remission and death.

RESULTS

Twenty-seven cases with granulomatosis with polyangiitis (GPA), 10 with eosinophilic GPA (EGPA), 81 with microscopic polyangiitis (MPA), and 25 with unclassified AAV were identified. The average age of MPO-ANCA-positive patients was 71.4 years. Comorbidity (87.4%) and airway comorbidity (70.6%) were frequently observed in these patients. Examination of the clinical phenotypes revealed that the cases of GPA were frequently accompanied by infectious airway comorbidity (upper airway disease, bronchiectasis, pulmonary infections), and most of the cases of MPA and unclassified AAV were accompanied by fibrotic interstitial lung disease (fILD) or emphysema. Among MPO-ANCA-positive patients, infectious airway comorbidity was predictive of both remission (HR 1.58, P = 0.03) and mortality (HR 2.64, P = 0.04), and fILD was predictive of mortality (HR 7.55, P = 0.008). The combination of infectious airway comorbidities and fILD caused the worst survival outcomes in patients.

CONCLUSION

MPO-ANCA-positive AAV was frequently accompanied by airway comorbidities. In addition to fILD, infectious airway comorbidities were closely associated with those clinical phenotypes and outcomes.

Investigations in systemic vasculitis - The role of imaging

Imaging plays an increasing role for confirming a suspected diagnosis of giant cell arteritis (GCA) or Takayasu arteritis (TAK). Ultrasound, magnetic resonance imaging (MRI), and computed tomography demonstrate a homogeneous, most commonly concentric, arterial wall thickening. 18F-Fluorodeoxyglucose (FDG) positron emission tomography (PET) displays increased FDG uptake of inflamed artery walls delineating increased metabolism. Ultrasound and MRI are recommended to be the initial imaging modalities in cranial GCA and TAK, respectively. Extracranial disease can be confirmed by all four modalities, particularly by PET in case of inflammation of unknown origin. If the diagnosis remains uncertain, additional investigations including biopsy and/or additional imaging are recommended. Imaging should be performed by a trained specialist using appropriate operational procedures and settings with appropriate equipment. Further research is necessary on the role of imaging for disease monitoring. This review will discuss advantages and disadvantages of imaging modalities in the diagnosis of vasculitis.

Pulmonary Involvement in Systemic Vasculitis

PURPOSE OF REVIEW

The purpose of this study is to describe the most relevant advances concerning lung involvement in the ANCA-associated vasculitides (excluding eosinophilic granulomatosis with polyangiitis which may have different disease mechanisms). Focus is on pathophysiology, recent important imagenological procedures, treatment, and outcome.

RECENT FINDINGS

Emerging information exists on potential newly investigated diagnostic procedures (v.g. transbronchial cryobiopsies), detailed tomographic abnormalities, the potential favorable role of rituximab and the still uncertain one of plasma exchange in the treatment, and the increasing description of interstitial lung disease. Survival is reduced in case of both, diffuse alveolar hemorrhage and diffuse parenchymal disease. There is the need to expand the knowledge concerning better long-term treatment options with specific regimes, and to incorporate other measures regarding integral treatment in patients afflicted with lung involvement these maladies, as the outcome seems adverse in this scenario.

Clinical significance of myeloperoxidase-anti-neutrophil cytoplasmic antibody in idiopathic interstitial pneumonias

Objective

Although a possible association among myeloperoxidase-anti-neutrophil cytoplasmic antibody (MPO-ANCA), microscopic polyangiitis (MPA), and idiopathic pulmonary fibrosis (IPF) has been suggested, the clinical significance of MPO-ANCA in idiopathic interstitial pneumonias (IIPs), including IPF and non-IPF, remains unclear. We aimed to investigate the frequency of MPO-ANCA positivity, as well as MPA incidence and risk factors for development in patients initially diagnosed with IIP.

Methods

We retrospectively analysed 305 consecutive patients who were initially diagnosed as IIP and had MPO-ANCA results available.

Results

Of the 305 patients, 26 (8.5%) were MPO-ANCA-positive. Baseline characteristics were similar between the MPO-ANCA-positive and -negative patients. The cumulative 5-year MPA incidence was 24.3% in the MPO-ANCA-positive patients and 0% in the -negative patients (P < 0.0001). MPO-ANCA was positive in 15 of 133 (11.3%) patients initially diagnosed with IPF and in 11 of 172 (6.3%) patients initially diagnosed with non-IPF (P = 0.56), with cumulative 5-year MPA incidence of 6.2% and 1.0%, respectively (P = 0.10). Multivariate analysis revealed that UIP pattern on HRCT (HR = 3.20, P < 0.01) and no treatment for IIP (HR = 3.52, P < 0.01) were independently associated with MPA development in MPO-ANCA-positive patients.

Conclusion

MPO-ANCA positivity was uncommon, but was associated with subsequent MPA development in patients initially diagnosed with IIP, including both IPF and non-IPF cases. The study suggested that attention should be paid to MPA development in MPO-ANCA-positive IIP patients with UIP pattern on HRCT and those without treatment for IIP.

From fibrosis to diagnosis: a paediatric case of microscopic polyangiitis and review of the literature

We herein describe a case of a 6-year-old girl diagnosed with microscopic polyangiitis (MPA) after a long diagnostic process demanding the cooperation of paediatric respiratory medicine specialists, rheumatologists, nephrologists and radiologist. First symptoms of MPA were observed after Mycoplasma pneumoniae infection and included persistent crepitations at the basis of both lungs and mild haematuria. CT imaging showed features of lung fibrosis, renal biopsy was indicative of mesangial proliferative glomerulonephritis, in the skin biopsy features of microscopic polyangiitis were described. In the laboratory tests pANCA antibodies specific for myeloperoxidase (MPO) were present in high titer. MPA with initial features of lung fibrosis is an unusual presentation of this rare disease, usually observed in adult population. This unique case illustrates the diagnostic and therapeutic challenges in paediatric vasculitis patients with an unusual initial presentation in the form of interstitial lung disease. In the manuscript we also discuss the possible aetiology of lung fibrosis in microscopic polyangiitis MPA and provide the review of the current literature on the topic of childhood-onset MPA.

Interstital lung disease in ANCA vasculitis

Anti-neutrophil cytoplasmic antibodies (ANCA) vasculitides are immune-mediated disorders that primarily affect small blood vessels of the airway and kidneys. Lung involvement, one of the hallmarks of microscopic polyangiitis and granulomatosis with polyangiitis, is associated with increased mortality and morbidity. In recent years, several retrospective series and case reports have described the association of interstitial lung disease (ILD) and ANCA vasculitis, particularly those positive for ANCA specific for myeloperoxidase. In the majority of these patients pulmonary fibrosis occurs concurrently or predates the diagnosis of ANCA vasculitis. More importantly, these studies have shown that ILD has an adverse impact on the long-term prognosis of ANCA vasculitis. This review focuses on the main clinical and radiologic features of pulmonary fibrosis associated with anti-neutrophil cytoplasmic antibodies. Major histopathology features, prognosis and therapeutic options are summarized.