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.

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.

Interstitial lung disease in microscopic polyangiitis and granulomatosis with polyangiitis: demographic, clinical, serological and radiological features of an Italian cohort from the Italian Society for Rheumatology.

OBJECTIVES: Interstitial lung disease (ILD) has been described as a possible pulmonary involvement in antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitides (AAV), mainly granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). Aim of this cross-sectional Italian national study was to describe demographic, clinical and serological profile of ILD related to MPA and GPA and investigate possible correlations between radiologic patterns of ILD and vasculitis features. METHODS: We enrolled 95 consecutive patients with AAV-ILD, 56 affected by MPA (58.9%) and 39 by GPA (41.1%). RESULTS: NSIP was the most frequently detected ILD pattern, observed in c-ANCA patients in 60.9% of cases, followed by UIP pattern mainly observed in p-ANCA patients (47.7%, p=0.03). ILD represented the first clinical manifestation, preceding vasculitis diagnosis in 22.1% of cases and, globally, ILD was already detectable at AAV diagnosis in 66.3% of patients. The diagnosis of ILD preceded that of AAV in 85.7% of p-ANCA positive-patients, while only one patient with c-ANCA developed ILD before AAV (p= 0.039). Multivariate analysis confirmed the correlation of UIP pattern with p-ANCA-positivity and a diagnosis of ILD before AAV, also when adjusted for age and sex. CONCLUSIONS: Our study confirms that UIP is a frequent pattern of lung disease in AAVILD patients. Our results also suggest that ILD can represent an early complication of AAV but also occur in the course of the disease, suggesting the need of a careful evaluation by both pulmonologist and rheumatologist to achieve an early diagnosis. Further prospective studies are needed to define ILD prevalence and evolution in AAV patients.

Initial serum GM-CSF levels are associated with the severity of cerebral small vessel disease in microscopic polyangiitis patients.

Serum cytokine levels were comprehensively measured, and the association with cerebrovascular lesions on brain magnetic resonance imaging (MRI) in microscopic polyangiitis (MPA) patients was investigated. The initial serum granulocyte-macrophage colony-stimulating factor (GM-CSF) levels were significantly higher in the high-grade white matter hyperintensities (WMH) group than those in the low-grade WMH group. In multivariate analyses, high serum levels of GM-CSF were independently associated with high-grade WMH. The initial serum GM-CSF levels correlated positively with the Birmingham Vasculitis Activity Score and semi-quantitative scales of WMH. The initial serum GM-CSF levels were associated with the severity of WMH in MPA patients.

Clinical features and prognosis of microscopic polyangiitis with usual interstitial pneumonia compared with idiopathic pulmonary fibrosis.

INTRODUCTION: Pulmonary involvement in microscopic polyangiitis (MPA) is common, little is known about the clinical features of MPA with interstitial pneumonia (MPA-IP). OBJECTIVES: This study aimed to explore the prevalence of microscopic polyangiitis associated usual interstitial pneumonia (UIP)(MPA-UIP) and compare its clinical features and prognosis with those of MPA-non-UIP and idiopathic pulmonary fibrosis (IPF). METHODS: A total of 73 patients with MPA-IP were identified and divided into MPA-UIP patients and MPA-non-UIP patients. The clinical characteristics and survival of MPA-UIP patients were analysed and compared with those of MPA-non-UIP patients and 68 patients with IPF. RESULTS: The results showed that 34/73 (47%) MPA-IP patients were classified as MPA-UIP patients. Compared with MPA-non-UIP patients, MPA-UIP patients tend to have longer duration of symptoms prior to diagnosis and usually have pulmonary involvement as the initial presentation. However, they were less likely to have proteinuria and/or hematuria. Compared with IPF patients, MPA-UIP patients usually had multisystem damage, positive anti-neutrophil cytoplasmic autoantibodies and elevated levels of nonspecific inflammatory markers. MPA-UIP death was concentrated mainly in the first 3 months after diagnosis and resulted in a higher early mortality compared with IPF. CONCLUSION: UIP is the most frequent type of MPA-IP. These patients tend to have longer duration of symptoms prior to diagnosis and usually have pulmonary involvement as the first presentation. However, they are less likely to have proteinuria and/or hematuria. MPA patients with UIP can be differentiated from IPF patients through comprehensive analysis of clinical and laboratory findings.

Bronchiectasis is highly prevalent in anti-MPO ANCA-associated vasculitis and is associated with a distinct disease presentation.

OBJECTIVES: To assess the prevalence of bronchiectasis in a Western cohort with ANCA-positive granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA) and its correlations with disease presentation and outcome. METHODS: Retrospective study of ANCA-associated vasculitis (AAV) patients followed at Nantes University Hospital (2005-2015). Clinical, biological, and follow-up data were collected through chart review. Two experienced radiologists blinded to the clinical data interpreted chest high-resolution CTs according to the Feischner Society criteria. RESULTS: Fifty-eight patients were included: 30 had MPA (51.7%) and 28 had GPA (48.3%). The median age at AAV diagnosis was 65.5 years. Anti-MPO-ANCA and anti-PR3-ANCA were present in 39 (67.2%) and 19 (32.8%) patients, respectively. Overall, bronchiectasis was found in 22 patients (37.9%), all of whom had anti-MPO ANCA. In multivariate analysis, bronchiectasis was independently associated with anti-MPO-ANCA, female gender and age at AAV diagnosis. Furthermore, anti-MPO ANCA patients with bronchiectasis had more frequent peripheral nerve involvement (54.5 vs. 17.6%, p = 0.019) and less frequent renal involvement than those without bronchiectasis (40.9% vs. 82.3%, p = 0.009). Disease course, survival and risk of severe pulmonary infection were similar in patients with and without bronchiectasis on chest CT. CONCLUSIONS: This study shows that bronchiectasis is a highly prevalent pre-existing respiratory condition in Caucasian patients with anti-MPO AAV. This subset of patients exhibits a distinct presentation. Further studies are needed to confirm these findings and clarify the clinical implications of this association. Whether the respiratory tract could be the site of initiation of anti-MPO auto-immunity remains to be investigated.

Microscopic Polyangiitis with Spinal Cord Involvement: A Case Report and Review of the Literature.

BACKGROUND: Microscopic polyangiitis (MPA) is an ANCA-associated vasculitis (AAV; ANCA denotes antineutrophil cytoplasmic antibody) that causes necrotizing inflammation of small blood vessels. Renal and pulmonary manifestations are common whereas central nervous system (CNS) involvement, and in particular spinal disease, is rare. METHODS: We reviewed a case of MPA presenting with spinal intradural hemorrhage and intracerebral hemorrhage. We also summarized all reported cases of AAV with spinal cord involvement in the literature (database search included MEDLINE, Embase, Scopus, and Proquest with no date or language restriction). RESULTS: We reviewed 20 cases of AAV with spinal cord involvement (12 granulomatosis with polyangiitis [GPA], 4 eosinophilic granulomatosis with polyangiitis, 2 MPA, and 2 cases diagnosed as AAV only) and reported demographic information, clinical features, methods of diagnosis, treatment, and patient outcome. Although CNS involvement has been associated with a poor prognosis, 14 of 18 cases that reported outcome data achieved remission during follow-up. Death occurred in 3 patients diagnosed with GPA and in 1 patient with MPA. Our patient with MPA deteriorated rapidly despite use of prednisone and died. CONCLUSIONS: AAV can present with brain and spinal cord involvement, even in the absence of systemic disease. CNS disease may be responsive to immunosuppressive therapy (e.g., steroids and cyclophosphamide) in several of the cases reviewed.

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.

OBJECTIVE: To determine the prevalence of lung abnormalities on chest computed tomography (CT) in patients with microscopic polyangiitis (MPA), to assess the responsiveness of such abnormalities to initial treatment, and to assess associations between these abnormalities and patient and disease characteristics and mortality. METHODS: We retrospectively identified 167 consecutive hospital-based patients with MPA in 3 hospitals in Japan. We longitudinally collected clinical information for 150 of these patients, for whom CT images obtained before treatment were available. We then determined the presence of 22 imaging components of lung abnormalities in these patients. RESULTS: The vast majority of patients (97%) had at least 1 lung abnormality on chest CT images, including interstitial lung lesions (66%), airway lesions (66%), pleural lesions (53%), and emphysematous lesions (37%). In multivariate analyses, ground-glass opacity was associated with the Birmingham Vasculitis Activity Score, whereas 3 of 4 airway lesions were associated with myeloperoxidase-antineutrophil cytoplasmic antibodies. Latent class analysis identified a distinct group of patients with airway-predominant lung lesions. Airway lesions such as bronchiolitis and bronchovascular bundle thickening were among the components that showed improvement within 3 months of the initial treatment. An idiopathic pulmonary fibrosis pattern was the only chest CT variable that was independently associated with shorter survival. CONCLUSION: Abnormalities in a wide range of anatomic areas, including the whole airway, can be identified in the lungs of patients with MPA before treatment. The prevalence, clustering patterns, and responsiveness to treatment of individual lung abnormalities provide groundwork for informing future studies to understand the pathophysiology of MPA.

A case of microscopic polyangiitis with skin manifestations in a seven-year-old girl.

A case of a 7-year-old girl with microscopic polyangiitis (MPA) with a skin eruption characterized by maculopapular, erythematous and purpuric lesions on the face, elbows, and knees is presented. Anti-neutrophil cytoplasmic autoantibodies (ANCA) with myeloperoxidase specificity (MPO-ANCA) were identified. Chest X-ray and computed tomography scan revealed diffuse infiltrates in both lung fields, suggesting alveolar hemorrhage. Microscopic hematuria was detected but a renal biopsy showed no abnormalities. Histological examination of a skin biopsy from a purpuric papule showed leukocytoclastic vasculitis of the small vessels in the entire dermis. The patient was treated with prednisolone and mizoribine, resulting in an improvement in the skin lesions except for those on the knee.

Incidence of myeloperoxidase anti-neutrophil cytoplasmic antibody positivity and microscopic polyangitis in the course of idiopathic pulmonary fibrosis.

BACKGROUND: Pulmonary fibrosis is a manifestation of microscopic polyangitis (MPA), and often precedes the detection of MPA. The prevalence and sequence of myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA) and MPA in patients initially diagnosed with idiopathic pulmonary fibrosis (IPF) have not been precisely elucidated. METHODS: We enrolled 61 consecutive patients with IPF and measured the MPO-ANCA titers at initial presentation and during the follow-up period. Clinical, radiologic and histologic features of MPO-ANCA-positive cases were examined. RESULTS: Of 61 patients, 3 (4.9%) had positive MPO-ANCA titers at the initial presentation of IPF. During the disease course, MPO-ANCA-positive conversion occurred in 6 patients and the prevalence of ANCA increased to 14.8%. Among the nine patients positive for MPO-ANCA, two patients developed MPA during follow-up. Histologic features of MPO-ANCA-positive pulmonary fibrosis were compatible with the usual interstitial pneumonia pattern in which alveolar hemorrhage and capillaritis were not observed. The patients with MPO-ANCA-positive conversion showed increased percentages of bronchoalveolar lavage eosinophils and more frequent complication of pulmonary emphysema compared to those with MPO-ANCA-negative IPF. CONCLUSIONS: The findings of the present study demonstrated that patients with an initial diagnosis of IPF occasionally acquire MPO-ANCA, which develops to MPA during the disease course of IPF. The presence of pulmonary eosinophilia and low attenuation areas on computed tomography scans might be predictive of MPO-ANCA positive conversion.