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

Antineutrophil cytoplasmic antibody is an independent risk factor in rheumatoid arthritis-associated interstitial lung disease

OBJECTIVES

This study aimed to investigate the clinical relevance of antineutrophil cytoplasmic antibody (ANCA) in patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD).

METHODS

Detailed clinical records of rheumatoid arthritis (RA) patients who underwent ANCA screening tests were collected. ANCA measurements were determined by indirect immunofluorescence assay (IIF) and enzyme-linked immunosorbent assay (ELISA). Clinical characteristics were compared between ANCA-positive and ANCA-negative groups, and multivariable logistic models were used to evaluate the independent association of ANCA with ILD in RA patients.

RESULTS

The prevalence of ANCA by IIF was significantly higher in RA-ILD patients compared to those with RA without ILD (31.7 % vs. 19.5 %, p < 0.001). RA-ILD patients positive for ANCA exhibited elevated levels of inflammatory markers and greater disease activity, and showed more severe impairment of lung function compared to ANCA-negative RA-ILD patients. Multivariable logistic regression analysis revealed an independent association of ANCA, especially pANCA, with RA-ILD. ANCA specificities for BPI, elastase, and cathepsin-G were found in 15.6 % of RA-ILD patients; the specificities for most others remain unknown.

CONCLUSIONS

The findings suggest a potential role for ANCA/pANCA in stratifying the risk of RA and provide supplementary information to the existing clinically available assays. This additional information may be valuable in identifying RA patients who require further investigations for RA-ILD, such as high-resolution computed tomography (HRCT). These results emphasize the potential clinical relevance of ANCA in the context of RA-ILD.

Presentation and progression of MPO-ANCA interstitial lung disease

The association between MPO-ANCA-associated vasculitis (AAV) and interstitial lung disease (ILD) has been well established. Pulmonary fibrosis may coexist with, follow, or even precede the diagnosis of AAV, and its presence adversely affects the prognosis. The optimal approach to investigating ANCA in patients with ILD remains a subject of ongoing debate. Here we aim to describe presentation and progression of MPO-ANCA ILD. We conducted a retrospective evaluation of a cohort of individuals diagnosed with MPO-ANCA ILD, with or without accompanying renal impairment, at the Immunology and Cell Therapy Unit, Careggi University Hospital, Florence, Italy, between June 2016 and June 2022. Clinical records, imaging studies, pathologic examinations, and laboratory test results were collected. Among the 14 patients identified with MPO-ANCA ILD, we observed a significant association between MPO-ANCA titers assessed at the time of ILD diagnosis and renal involvement. Renal impairment in these cases often manifested as subclinical or slowly progressive kidney damage. Interestingly, complement C3 deposits were consistently found in all renal biopsy specimens, thereby suggesting the potential for novel therapeutic targets in managing renal complications associated with MPO-ANCA ILD. The presentation of MPO-ANCA vasculitis as ILD can be the first and only clinical manifestation. MPO-ANCA levels at ILD diagnosis could warn on the progression to renal involvement in patients with MPO-ANCA ILD, hence caution is needed because renal disease can be subclinical or smoldering.

Pathogenesis of Pulmonary Manifestations in ANCA-Associated Vasculitis and Goodpasture Syndrome

Pulmonary manifestations of vasculitis are associated with significant morbidity and mortality in affected individuals. They result from a complex interplay between immune dysregulation, which leads to vascular inflammation and tissue damage. This review explored the underlying pathogenesis of pulmonary involvement in vasculitis, encompassing various forms such as granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), eosinophilic granulomatosis with polyangiitis (EGPA), and anti-GBM disease. Mechanisms involving ANCA and anti-GBM autoantibodies, neutrophil activation, and neutrophil extracellular trap (NETs) formation are discussed, along with the role of the complement system in inducing pulmonary injury. Furthermore, the impact of genetic predisposition and environmental factors on disease susceptibility and severity was considered, and the current treatment options were presented. Understanding the mechanisms involved in the pathogenesis of pulmonary vasculitis is crucial for developing targeted therapies and improving clinical outcomes in affected individuals.

Comparison of Interstitial Lung Disease Between Antineutrophil Cytoplasmic Antibodies Positive and Negative Patients: A Retrospective Cohort Study

OBJECTIVE

Positive antineutrophil cytoplasmic antibodies (ANCAs) may occur in the setting of interstitial lung disease (ILD), with or without ANCA-associated vasculitis (AAV). We aim to compare the characteristics and clinical course of patients with ILD and positive ANCA (ANCA-ILD) to those with negative ANCA.

METHODS

We performed a single-center retrospective cohort study from 2018 to 2021. All patients with ILD and ANCA testing were included. Patient characteristics (symptoms, dyspnea scale, and systemic AAV), test results (pulmonary high-resolution computed tomography and pulmonary function tests), and adverse events were collected from electronic medical records. Descriptive statistics and the Fisher exact test were used to compare the outcomes of patients with ANCA-ILD to those with ILD and negative ANCA.

RESULTS

A total of 265 patients with ILD were included. The mean follow-up duration was 69.3 months, 26 patients (9.8%) were ANCA positive, and 69.2% of those with ANCA-ILD had another autoantibody. AAV occurred in 17 patients (65.4%) with ANCA-ILD. In 29.4% of patients, AAV developed following ILD diagnosis. Usual interstitial pneumonia was the most common radiologic pattern in patients with ANCA-ILD. There was no association between ANCA status and the evolution of dyspnea, diffusing capacity of the lungs for carbon monoxide, and lung imaging. Forced vital capacity improved over time in 42% of patients with ANCA-ILD and in 17% of patients with negative ANCA (P = 0.006). Hospitalization occurred in 46.2% of patients with ANCA-ILD and in 21.8% of patients with negative ANCA (P = 0.006). Both groups had similar mortality rates.

CONCLUSION

Routine ANCA testing should be considered in patients with ILD. Patients with ANCA-ILD are at risk for AAV. More research is required to better understand and manage patients with ANCA-ILD.

Interstitial lung diseases associated with ANCA positivity: A different disease spectrum from interstitial pneumonia with autoimmune features

BACKGROUND

Anti-neutrophil cytoplasmic antibody (ANCA) is a type of autoantibodies associated with vasculitis. ANCA positivity is commonly observed in interstitial lung disease (ILD) patients. 7%-10% of ANCA-positive ILD patients don't present any symptoms of systemic vasculitis and are termed ANCA-positive idiopathic interstitial pneumonia (ANCA-IIP). Some researchers propose that ANCA-IIP should be categorized as interstitial pneumonia with autoimmune features (IPAF), although the official ATS/ERS statements exclude ANCA-IIP from this classification. Whether ANCA-IIP should be categorized into the entity of IPAF is still debatable.

METHODS

Patients diagnosed with ANCA-IIP and those with IPAF were analyzed in a retrospective study of ILD. The clinical outcomes were determined through pulmonary function tests (PFTs) after a one-year follow-up, as well as assessing all-cause mortality.

RESULTS

27 patients with ANCA-IIP and 143 patients with IPAF were analyzed from a cohort of 995 patients with ILD. Patients in the ANCA-IIP group had an older age and a high proportion of males compared to those in the IPAF group. PFT results at baseline were similar between the two groups, except for a better FEV1% in the ANCA-IIP group. Glucocorticoid and immunosuppressive therapy improved pulmonary function in patients with IPAF, but it continued to deteriorate after one year of treatment in the ANCA-IIP group. Furthermore, the all-cause mortality rate was significantly higher in the ANCA-IIP group than in the IPAF group (22.2% vs. 6.3%, P = 0.017).

CONCLUSION

The responses to glucocorticoid and immunosuppressive therapy differ between the ANCA-IIP and IPAF groups, leading to divergent prognoses. Therefore, it is inappropriate to classify ANCA-IIP as part of IPAF.

Development of a novel predictive model for interstitial lung disease in ANCA-associated vasculitis prognostications within the Chinese population

Antineutrophil cytoplasmic antibody vasculitis-associated interstitial lung disease (AAV-ILD) is a potentially life-threatening disease. However, very little research has been done on the condition's mortality risk. Hence, our objective is to find out the factors influencing the prognosis of AAV-ILD and employ these findings to create a nomogram model. Patients with AAV-ILD who received treatment at the First Affiliated Hospital of Zhengzhou University during the period from March 1, 2011, to April 1, 2022 were selected for this research. The development of nomogram entailed a synergistic integration of univariate, Lasso, and multivariate Cox regression analyses. Internal validation ensued through bootstrap techniques involving 1000 re-sampling iterations. Discrimination and calibration were assessed utilizing Harrell's C-index, receiver operating characteristic (ROC) curve, and calibration curve. Model performance was evaluated through integrated discrimination improvement (IDI), net reclassification improvement (NRI), and likelihood ratio test. The net benefit of the model was evaluated using decision curve analysis (DCA). A cohort comprising 192 patients was enrolled for analysis. Throughout observation period, 32.29% of the population died. Key factors such as cardiac involvement, albumin, smoking history, and age displayed substantial prognostic relevance in AAV-ILD. These factors were incorporated to craft a predictive nomogram. Impressively, the model exhibited robust performance, boasting a Harrell's C index of 0.826 and an AUC of 0.940 (95% CI 0.904-0.976). The calibration curves depicted a high degree of harmony between predicted outcomes and actual observations. Significantly enhancing discriminative ability compared to the ILD-GAP model, the nomogram was validated through the IDI, NRI, and likelihood ratio test. DCA underscored the superior predictive value of the predictive model over the ILD-GAP model. The internal validation further affirmed this efficacy, with a mean Harrell's C-index of 0.815 for the predictive model. The nomogram model can be employed to predict the prognosis of patients with AAV-ILD. Moreover, the model performance is satisfactory. In the future, external datasets could be utilized for external validation.

A unique case of indolent microscopic polyangiitis in an elderly gentleman: a case report and brief review

Antineutrophil cytoplasmic autoantibody associated vasculitides has 3 different types: Granulomatosis with polyangiitis, eosinophilic granulomatosis and polyangiitis and microscopic polyangiitis. These vasculitides manifest differently based on which area of small and medium size vessels in our bodies that it affects. In this case report, we discuss a unique case of microscopic polyangiitis diagnosed in a 75-year-old male who was relatively asymptomatic i.e. indolent, apart from nodules present in the lung with the use of the diagnostic criteria outlined by 2022 American College of Rheumatology and European Alliance of Associations for Rheumatology. In addition, we reviewed briefly about vasculitis, its epidemiology and the workup of microscopic polyangiitis.

Microscopic polyangiitis initially presenting with idiopathic pulmonary fibrosis: a case report

Usual interstitial pneumonia is the most common type of microscopic polyangiitis (MPA)-associated interstitial lung disease, and patients may initially present with isolated pulmonary fibrosis, which often leads to a misdiagnosis of idiopathic pulmonary fibrosis (IPF). Here, we describe a patient who developed fever of unknown origin, microscopic hematuria and renal insufficiency, who then tested positive for antineutrophil cytoplasmic antibody (ANCA) and was diagnosed with MPA after receiving antifibrotic medication for IPF (original diagnosis) for almost 10 years. The patient's symptoms were ameliorated after administration of additional glucocorticoids and immunosuppressants.

An unexpected diagnosis of a 57-year-old women with migratory pulmonary infiltrates

A 57-year-old female presented with sudden shortness of breath and migratory pulmonary infiltrates on imaging, which corresponds with a diagnosis of cryptogenic organizing pneumonia. Initial treatment with corticosteroids showed only mild improvement during follow-up. BAL was performed and revealed diffuse alveolar hemorrhage. Immune testing showed positive P-ANCA with positive MPO, leading to a diagnosis of microscopic polyangiitis.

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.

MPO-ANCA-positive conversion and microscopic polyangiitis development in idiopathic interstitial pneumonia: a case report

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is a systemic autoimmune disease characterized by necrotizing inflammation of the small blood vessels. ANCA-associated vasculitis is subclassified into three variants: granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, and microscopic polyangiitis (MPA). Myeloperoxidase (MPO) ANCA is a marker antibody for MPA. Interstitial pneumonia (IP) is occasionally complicated with MPA. However, only a few cases of idiopathic IP develop MPO-ANCA-positive conversion and MPA. Therefore, we present a case of a 70-year-old Japanese man with idiopathic IP who developed MPO-ANCA-positive conversion and MPA. We performed renal biopsy, which revealed pauci-immune crescentic glomerulonephritis. The patient was treated with intravenous methylprednisolone pulse therapy and oral prednisone, and the patient's laboratory data gradually improved with steroid therapy. The association between the production of MPO-ANCA and IP remains unclear, and the present case suggests that IP plays a role in inducing MPO-ANCA production. Patients with idiopathic IP should be followed-up carefully for an examination of increased MPO-ANCA levels and MPA development. In addition, early gastric cancer was detected during upper gastrointestinal endoscopy in our case, and it could also be important not to miss malignancy in patients with ANCA-associated vasculitis.

Interstitial lung disease in ANCA-associated vasculitis: associated factors, radiographic features and mortality

OBJECTIVE

To evaluate the prevalence, clinical and radiographic features, and long-term outcomes of interstitial lung disease (ILD) in a United States-based ANCA-associated vasculitis (AAV) cohort.

METHODS

In this retrospective cohort study, we identified cases of ILD within the 2002-2019 Mass General Brigham AAV Cohort, a consecutive inception cohort of PR3- or MPO-ANCA+ AAV patients. ILD diagnosis and classification as fibrotic or non-fibrotic were confirmed by review of available chest imaging by two board-certified radiologists. Cox proportional hazard models, with age as the time scale, were used to estimate the association of AAV-ILD with all-cause mortality.

RESULTS

Of 684 patients in the MGB AAV Cohort, 91 (13%) had ILD which preceded the diagnosis of AAV by a mean of 2.2 years. AAV-ILD patients were older (67 vs 60 years, P < 0.001) than patients without ILD but the distribution of sex and race was similar. AAV-ILD patients were more often MPO-ANCA+ (93% vs 65%, P < 0.001); among MPO-ANCA+ patients (n = 470), 85 (18%) had ILD. The majority of ILD was fibrotic (76%) and UIP was the most common ILD pattern (42%). The baseline forced vital capacity (FVC) % predicted among ILD patients was 81 ± 20%. Fibrotic AAV-ILD was associated with a 58% higher risk of death (aHR 1.58, 95% CI 1.06, 2.37) compared with AAV patients without ILD.

CONCLUSION

ILD is a frequent complication of AAV, especially MPO-ANCA+ AAV, often preceding recognition of AAV. Fibrotic AAV-ILD is associated with a higher risk of death than AAV without ILD.

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.

Management of progressive pulmonary fibrosis associated with connective tissue disease

INTRODUCTION

: Fibrotic interstitial lung disease (ILD) is a frequent and severe complication of connective tissue disease (CTD).

AREAS COVERED

: In this narrative review, we update the most relevant differential characteristics of fibrotic ILD associated with CTD (CTD-ILD) and propose a diagnostic and therapeutic approach based on a review of the articles published between 2002 and 2022 through PubMed.

EXPERT OPINION

: The subset of ILD, mainly the radiological/histological pattern and the degree of fibrotic component, usually determines the prognosis and therapeutic strategy for these patients. Some patients with CTD-ILD can develop progressive pulmonary fibrosis (PPF) with severe deterioration of lung function, rapid progression to chronic respiratory failure, and high mortality. PPF has been described in many CTDs, mainly in systemic sclerosis and rheumatoid arthritis, and requires a multidisciplinary diagnostic and therapeutic approach to improve patient outcomes.

ANCA-associated vasculitis in idiopathic pulmonary fibrosis: A case report and brief review of the literature

RATIONALE

Idiopathic pulmonary fibrosis (IPF) is a progressive disease with poor prognosis. Patients with IPF represent a heterogeneous population with several described clinical phenotypes. More recently, the development of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis in IPF patients, with an incidence higher than that in the general population, has drawn attention.

PATIENT CONCERNS

A 64-year-old woman previously diagnosed with IPF presented to the emergency department with hemoptysis and hypoxemic respiratory failure.

DIAGNOSES

High-resolution chest computed tomography revealed bilateral ground-glass opacities associated with areas of consolidation superimposed on the patient's fibrotic background pattern. Diffuse alveolar hemorrhage was confirmed by the presence of hemorrhagic bronchoalveolar lavage fluid. Hematological and biochemical investigations revealed an inflammatory syndrome, moderate anemia, and rapidly progressive glomerulonephritis. Serological analysis revealed perinuclear antineutrophil cytoplasmic antibody positivity and high levels of antimyeloperoxidase antibodies antibodies. The patient underwent kidney biopsy, which revealed necrotizing glomerulonephritis. Clinical and laboratory findings were diagnostic of microscopic polyangiitis with lung and renal involvement.

INTERVENTIONS

Cyclophosphamide in combination with methylprednisolone was administered as remission induction therapy. The maintenance therapy consisted of mycophenolate mofetil and prednisone.

OUTCOMES

The patient achieved clinical, radiological, and serological remission within six weeks of treatment.

LESSONS

The association between IPF and ANCA-associated vasculitis may represent a distinct clinical phenotype. Autoimmune testing for ANCAs should be considered part of the diagnostic work-up and follow-up of patients with IPF because of the clinical and therapeutic implications of developing vasculitis in an already vulnerable patient.

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.

Prognostic value of radiological findings indeterminate for UIP pattern and anterior upper lobe honeycomb-like lesion in chronic fibrosing interstitial lung disease associated with MPO-ANCA

Background

Myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) is often positive in patients with interstitial lung disease (ILD), which is also often present in patients with microscopic polyangiitis (MPA). A possible association between MPO-ANCA, MPA, and idiopathic ILD remains unclear. The objective of this study was to determine whether high-resolution computed tomography (HRCT) classification based on recent idiopathic pulmonary fibrosis guideline and specific CT findings can obtain new knowledge of prognostic factors in all MPO-ANCA-positive patients with ILD including both idiopathic ILD and MPA-ILD.

Methods

We analyzed 101 consecutive MPO-ANCA-positive patients with respiratory disease. We assessed the diagnostic accuracy of CT findings, HRCT pattern, and specific radiological signs. Prognostic predictors were determined using Cox regression models.

Results

Subjects with chronic ILD included 22 patients with MPA-ILD and 39 patients with ILD but without MPA. A quarter of the patients were radiological indeterminate for usual interstitial pneumonia (UIP) pattern, which resulted in a better prognosis than that for UIP pattern. “Increased attenuation around honeycomb and traction bronchiectasis” and “anterior upper lobe honeycomb-like lesion” were found to be highly frequent radiological findings (39% and 30%, respectively). In addition, the latter finding was a significant negative prognostic factor.

Conclusions

Radiological indeterminate for UIP was a useful HRCT classification in MPO-ANCA-positive patients with ILD. In addition, anterior upper lobe honeycomb-like lesion was found to be specific radiological finding that was a significant prognostic factor. The present results might aid in the assessment of appropriate strategies of diagnosis in these patients.

Salivary gland involvement in ANCA-associated vasculitis

OBJECTIVE

Salivary gland involvement in anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis is rare, but can lead to the misdiagnosis of other diseases. The objective of this study was to clarify the characteristics of patients with salivary gland involvement.

METHODS

We conducted a systematic literature review of articles reporting salivary gland involvement in ANCA-associated vasculitis from the inception dates until May 2, 2021.

RESULTS

We identified 58 patients with salivary gland involvement. The mean age was 52 years, and men were predominantly affected (59%). Half of the patients presented with fever. Swelling of the salivary gland was the initial manifestation in 88% of the patients, unilaterally affected in 53%, and painful in 47%. The affected salivary glands were as follows: parotid gland alone (53%), submandibular gland alone (33%), and both parotid and submandibular glands (14%). Additionally, two patients had sublingual gland involvement. The most frequent clinical diagnosis was granulomatosis with polyangiitis (83%), followed by eosinophilic granulomatosis with polyangiitis (17%), while no patient was diagnosed with microscopic polyangiitis. PR3-ANCA positivity (72%) was predominant to MPO-ANCA positivity (6%), and ANCA was negative in 22% of the patients. Among 37 ANCA-positive patients, 6 patients (16%) were initially ANCA-negative, but subsequently became positive during the clinical course. The serum C-reactive protein levels were elevated in all the examined patients. On contrast-enhanced computed tomography, a finding suggestive of necrosis, which was heterogeneous enhancement with low-density areas, was found in 33% of the patients. Vasculitis, granulomatous inflammation, necrosis, or the presence of multinucleated giant cells was found in 83% of the biopsy samples of the affected salivary gland. Glucocorticoids with or without other immunosuppressive agents, such as cyclophosphamide were effective in most patients, but twelve patients (21%) experienced a relapse of the disease and nine patients (16%) died during the clinical course.

CONCLUSION

Salivary gland involvement can be an initial manifestation of ANCA-associated vasculitis. The recognition of this unusual atypical presentation is important for the early and accurate diagnosis and treatment.

Myeloperoxidase and associated lung disease: Review of the latest developments

Myeloperoxidase (MPO) anti-neutrophil cytoplasmic antibodies (ANCA) are often detected in association with a variety of lung pathologies, the most common being interstitial lung disease (ILD). A growing cohort of patients are being diagnosed with MPO-ANCA in the context of ILD without ANCA-associated vasculitis. Clinically and radiologically, there is little to differentiate this cohort from MPO-ANCA-negative ILD patients; however, the pathophysiology is likely different and different treatments are likely required. We present here a brief summary of the proposed pathophysiology of MPO-ANCA-positive ILD, and a more detailed review of the latest evidence on management, including monitoring for development of ANCA-associated vasculitis, immunosuppression, anti-fibrotics, and novel agents that have yet to be trialled in human experiments.

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.

New therapeutic strategies in lung vasculitis

PURPOSE OF REVIEW

To summarize the latest publications and provide a practical overview of treatment strategies for lung vasculitis associated with antineutrophil cytoplasmic antibodies (ANCAs).

RECENT FINDINGS

In patients with severe ANCA-associated vasculitis, plasma exchange, as adjunctive therapy to standard treatment, is not associated with improved survival or reduced risk of end-stage kidney disease. A regimen with reduced dose of glucocorticoids is equally effective to induce remission as a standard regimen. In patients without organ or life-threatening disease, mycophenolate mofetil can be used in combination with oral glucocorticoid therapy to induce remission, however, with a higher risk of relapse than when using rituximab or cyclophosphamide. For maintenance of remission, a tailored regimen of rituximab infusion was equivalent to a fixed regimen, with fewer perfusions. Belimumab, a human IgG1(Equation is included in full-text article.)monoclonal antibody against B-lymphocyte stimulator, did not decrease the relapse rate when added to azathioprine and glucocorticoids. Avacopan, a complement C5a receptor inhibitor, was effective in replacing high-dose glucocorticoids in achieving complete remission of vasculitis.

SUMMARY

Significant advances have been made in the treatment strategy to both induce remission and maintain remission in patients with ANCA-associated vasculitis. The choice should take into consideration efficacy, cost-effectiveness, safety profile, ease of use, and possibility of individual tailoring of treatment.

Interstitial Lung Disease and Anti-Myeloperoxidase Antibodies: Not a Simple Association

Anti-neutrophil cytoplasmic antibodies (ANCA), mainly anti-myeloperoxidase (MPO) antibodies, have been frequently identified in patients with idiopathic pulmonary fibrosis (IPF). However, their role remains unclear, and only 7–23% of these patients develops clinically overt vasculitis. We aimed to investigate the clinical, serological, and radiological features and prognosis of anti-MPO-positive interstitial lung disease (ILD) patients. Fifty-eight consecutive patients firstly referred for idiopathic interstitial pneumonia and showing serological positivity of anti-MPO antibodies were retrospectively enrolled. For each patient, clinical data, lung function testing, chest high-resolution computed tomography (HRCT) pattern, and survival were recorded. Thirteen patients developed a rheumatic disease during a median follow-up of 39 months. Usual interstitial pneumonia (UIP) was the most frequent ILD pattern, significantly influencing the patients’ survival. In fact, while the 52-week survival of the overall population was 71.4 ± 7.5%, significantly higher than IPF, survivals of anti-MPO patients with UIP pattern and IPF were similar. Forced vital capacity and diffusion lung capacity for CO significantly declined in 37.7 and 41.5% of cases, respectively, while disease progression at chest HRCT was observed in 45.2%. A careful clinical history and evaluation should always be performed in ILD patients with anti-MPO antibodies to quickly identify patients who are developing a systemic rheumatic disease.

ANCA Status or Clinical Phenotype - What Counts More?

PURPOSE OF REVIEW

There is ongoing debate concerning the classification of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. That is, whether classification should be based on the serotype (proteinase 3 (PR3)- or myeloperoxidase (MPO)-ANCA) or on the clinical phenotype (granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA)). To add clarity, this review focused on integration of the most recent literature.

RECENT FINDINGS

Large clinical trials have provided evidence that a serology-based risk assessment for relapses is more predictive than distinction based on the phenotype. Research conducted in the past decade indicated that a serology-based approach more closely resembles the genetic associations, the clinical presentation (i.e., lung involvement), biomarker biology, treatment response, and is also predicting comorbidities (such as cardiovascular death). Our review highlights that a serology-based approach could replace a phenotype-based approach to classify ANCA-associated vasculitides. In future, clinical trials and observational studies will presumably focus on this distinction and, as such, translate into a "personalized medicine."

Risk of progression of idiopathic pulmonary fibrosis to connective tissue disease: a long-term observational study in 527 patients

OBJECTIVE

Connective tissue disease (CTD) might occur during the course of idiopathic pulmonary fibrosis (IPF). Clinical factors associated with CTD development in IPF patients have still not been identified. We investigated which antibodies have a significant association with the development of CTD during the clinical course of IPF.

METHODS

We retrospectively reviewed the records of 527 patients with a first diagnosis of IPF between January 2007 and March 2014 and investigated the time to CTD development after IPF diagnosis in these patients.

RESULTS

CTD developed in 15 patients at a median of 2.1 years (range 1.2-4.8) after IPF diagnosis. All patients had anti-neutrophil cytoplasmic antibodies (ANCA) or autoantibodies that met the serology criteria for interstitial pneumonia with autoimmune features (IPAF). Survival duration for IPF patients with progression to CTD was 5.3 (3.8, 6.7) years, which was significantly longer than for IPF patients without progression to CTD [2.9 (1.7, 4.8), p = 0.001]. Independent risk factors for CTD development in IPF patients included female gender [adjusted hazard ratio (HR) 5.319, p = 0.0082], titer of rheumatoid factor (RF; adjusted HR, 1.006; p = 0.022), titer of anti-citrullinated protein antibody (ACPA; adjusted HR, 1.009; p = 0.0011), and titer of myeloperoxidase (MPO)-ANCA (adjusted HR, 1.02; p < 0.0001).

CONCLUSION

Progression to CTD is uncommon in IPF patients. However, a significant number of IPF patients with high titers of RF, ACPA, or MPO-ANCA progressed to CTD. RF, ACPA, and MPO-ANCA might be significantly associated with CTD development in IPF patients. Key Points • A significant number of IPF patients with high titers of RF, ACPA, or MPO-ANCA progressed to CTD. • IPF/UIP with high titers of RF, ACPA, or MPO-ANCA might be the initial clinical manifestation of CTD. • RF, ACPA, and MPO-ANCA may be significantly associated with the development of pulmonary fibrosis in patients with CTD.

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.

Clinical implications of ANCA positivity in idiopathic pulmonary fibrosis patients

The diagnostic process of idiopathic interstitial pneumonias (IIPs) is complex and the underlying mechanisms that participate in these diseases still need to be fully understood. In 2015, the European Respiratory Society/American Thoracic Society Task Force on Undifferentiated Forms of Connective Tissue Disease-Associated Interstitial Lung Disease introduced the term “interstitial pneumonia with autoimmune features” (IPAF) to identify subjects with IIP and features suggesting background autoimmunity but not characterisable connective tissue disease (CTD) [1]. The need for a proper clinical, serological and morphological assessment of IIP was highlighted to identify potential subjects with IPAF and CTD-ILD. However, the measurement of anti-neutrophil cytoplasmic antibodies (ANCAs) is not included in the definition of IPAF and ANCA serological testing is only recommended in idiopathic pulmonary fibrosis (IPF) when a clinical suspicion of vasculitis exists [2]. As current research evaluates the prognostic relevance of autoimmune features in IIP, the clinical importance of ANCA positivity still needs to be determined.

ANCA positivity is uncommon in North American IPF patients. However, women with IPF who areMPO-positive have a considerable risk for developing clinical manifestations of vasculitis.http://bit.ly/2RlsQNP

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.

Clinical significance of autoantibody positivity in idiopathic pulmonary fibrosis

RATIONALE

The concept of interstitial pneumonia with autoimmune features (IPAF) was recently proposed by the American Thoracic Society. However, the clinical significance of the serologic domain of IPAF has not yet been established in idiopathic pulmonary fibrosis (IPF).

OBJECTIVES

We aimed to investigate the clinical significance of autoantibody positivity in IPF.

METHODS

We retrospectively reviewed the records of 512 patients diagnosed as IPF from January 2007 through March 2014. The patients were divided into two subgroups: (i) an autoantibody-positive IPF subgroup (n = 138), consisting of patients with anti-neutrophil cytoplasmic antibody (ANCA) or autoantibodies that met the criteria for the IPAF serologic domain; (ii) a lone IPF subgroup (n = 374), consisting of the rest of the IPF patients.

MEASUREMENTS AND MAIN RESULTS

Autoantibody-positivity (HR 0.736, p = 0.043) was an independent risk factors for 5-year mortality on multivariable analysis in the overall IPF patients. In the autoantibody-positive IPF patients, use of glucocorticoid (not for management of acute exacerbation, HR 2.121, p = 0.019), use of immunomodulators (HR 0.310, p = 0.002), malignancy (HR 3.359, p = 0.002), baseline forced vital capacity (HR 0.974, p = 0.017), baseline diffusing capacity of the lung for carbon monoxide (HR 0.981, p = 0.041), and baseline 6-min walk test distance (HR 0.996, p = 0.002) were independent risk factors for 5-year mortality.

CONCLUSIONS

Presence of ANCA or autoantibodies of the IPAF serologic domain in IPF patients is associated with better survival outcomes, and the use of immunomodulators is associated with superior survival outcomes.

Autoantibodies in interstitial lung diseases

The role of autoantibody testing for patients with interstitial lung disease is an evolving area. Recent guidelines recommend routine anti-nuclear antibodies, rheumatoid factor, and anti-citrullinated cyclic peptide antibody testing for patients undergoing diagnostic evaluation for interstitial lung disease, with further autoantibody testing reserved for selected cases guided by rheumatological features. Even this approach may miss patients with clinically significant autoantibodies when interstitial lung disease is the dominant or first manifestation of autoimmune disease. We retrospectively performed autoimmune serology in a clinically well characterised cohort of interstitial lung disease patients. Using stored serum, additional testing was performed to ensure all patients had complete autoantibody profiles including anti-nuclear antibodies, extractable nuclear antigen antibodies, double-stranded DNA antibodies, rheumatoid factor, anti-citrullinated cyclic peptide antibodies, anti-neutrophil cytoplasmic antibodies, and myositis antibodies. Eighty patients with interstitial lung disease, and available stored serum, were assessed. Mean age at interstitial lung disease diagnosis was 65.2 years and 42 patients were male. Positive autoimmune serology was found in 56 of 80 (70.0%) patients; the most common positive result was anti-nuclear antibodies (n=34; 42.5%). Myositis antibodies were detected in 13 of 80 (16.2%) patients. Four (5%) patients had elevated anti-citrullinated cyclic peptide antibodies, and two (2.5%) patients had detectable myeloperoxidase antibodies. Eleven (13.7%) patients with negative anti-nuclear antibodies had other significant disease associated autoantibodies. An extended panel of autoantibody testing may detect cases of connective tissue disease associated interstitial lung disease, regardless of clinical or radiological subtype, and prior to extra-pulmonary manifestations of systemic autoimmunity.

Prevalence and Clinical Significance of Antineutrophil Cytoplasmic Antibodies in North American Patients With Idiopathic Pulmonary Fibrosis

BACKGROUND

Antineutrophil cytoplasmic antibodies (ANCAs) have been reported to occur in 7% to 10% of patients with idiopathic pulmonary fibrosis (IPF), but their clinical relevance remains unclear. The aim of this study was to estimate the prevalence of ANCAs in a North American population with IPF and evaluate their clinical significance.

METHODS

This was a retrospective study of two independent cohorts of patients diagnosed with IPF at the University of California San Francisco (discovery cohort) and the University of Chicago (replication cohort). Myeloperoxidase (MPO) and proteinase 3 (PR3) ANCAs were measured in all patients. Prevalence and associations of ANCAs with clinical characteristics and transplant-free survival were evaluated.

RESULTS

A total of 14 of 353 (4.0%; 95% CI, 2.2-6.5) and 20 of 392 (5.1%; 95% CI, 3.1-7.8) patients with IPF were positive for ANCAs at the time of diagnosis in the discovery and replication cohorts, respectively. Among those positive for MPO antibodies, two of six (33%) in the discovery cohort and three of 12 (25%) in the replication cohort developed vasculitis. None of the patients who were PR3-positive developed vasculitis. Patients who were ANCA-positive were more likely to be women than patients who were ANCA-negative, and were more likely to have some ground-glass opacities on CT scan. In the combined cohort of 745 patients, median transplant-free survival was not significantly different in patients who were ANCA-positive vs ANCA-negative (P = .57).

CONCLUSIONS

ANCA positivity is uncommon in North American patients with IPF and not associated with baseline disease severity or transplant-free survival; however, a significant proportion of patients who are MPO-positive with IPF develop clinical vasculitis.

Systematic review and meta-analysis of clinical significance of autoantibodies for idiopathic pulmonary fibrosis

OBJECTIVE

To clarify clinical significance of the sole presence of autoantibodies for idiopathic pulmonary fibrosis (IPF) without any other symptoms or signs suggestive of autoimmune disease.

DESIGN

Systematic review and meta-analysis DATA SOURCES: Medline, EMBASE, Science Citation Index Expanded and Google Scholar were searched from 1 January 2002 through 12 February 2019.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Primary studies addressing all-cause mortality and the development of a defined autoimmune disease for IPF with autoantibodies were included for the review.

DATA EXTRACTION AND SYNTHESIS

Two reviewers extracted relevant data and assessed risk of bias independently. Meta-analysis was conducted using a random-effects model if three or more studies reported the same outcome for a certain autoantibody. The quality of evidence was assessed by the Grades of Recommendation, Assessment, Development and Evaluation system.

RESULTS

Out of 4603 records retrieved nine studies were included in this review. All studies contained some risk of bias. Based on pooled data myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) was significantly associated with microscopic polyangiitis incidence with risk ratio (RR) of 20.2 (95% CI: 7.22 to 56.4) and antinuclear antibody (ANA) was also significantly associated with the development of connective tissue diseases with RR of 7.11 (p=0.001) (10 cases in 157 patients with ANA) in one study. However, there was no significant association of autoantibodies with all-cause mortality aside from MPO-ANCA and proteinase 3-ANCA in one study each. MPO-ANCA was not demonstrated to be associated with all-cause mortality by meta-analysis. The quality of evidence was deemed as either low or very low.

CONCLUSIONS

The presence of autoantibodies such as MPO-ANCA and ANA was demonstrated to be associated with the development of some autoimmune diseases for patients with IPF although there was no difference of all-cause mortality. However, the results should be interpreted with caution due to low evidence level.

PROSPERO REGISTRATION NUMBER

CRD42017077336.

Radiologic and pathologic characteristics of myeloperoxidase-antineutrophil cytoplasmic antibody-associated interstitial lung disease: a retrospective analysis

Background

The association between interstitial lung disease (ILD) and myeloperoxidase (MPO)-antineutrophil cytoplasmic antibodies (ANCAs) has been described, but pathologic characteristics are not well characterized.

Objectives

We assessed the radiologic and pathologic characteristics of ILD in MPO-ANCA-positive patients and the association between ILD and vasculitis, particularly microscopic polyangiitis (MPA).

Methods

We retrospectively searched electronic health records to identify MPO-ANCA-positive patients with ILD who underwent surgical lung biopsy at our institution from January 1997 through August 2017. Demographic, clinical, imaging, and pathologic characteristics were analyzed.

Results

We identified 18 MPO-ANCA-positive patients with ILD. The median (range) age was 58 (43-75) years, and the cohort included 10 men (56%), 10 former smokers (56%), and 11 patients (61%) had clinical evidence of systemic vasculitis (MPA) at the time of diagnosis of ILD. On high-resolution computed tomography, the most common radiologic pattern was "inconsistent with usual interstitial pneumonia" (UIP) (n=14 [78%]); the other 4 patients (22%) fulfilled the radiologic criteria for the UIP pattern. Honeycombing was seen in 15 patients (83%). Ten patients (56%) had the UIP pattern on biopsy: 4 of these patients had additional inflammatory changes that were not typical of UIP (as seen in patients with idiopathic pulmonary fibrosis), and the other 6 patients had other inflammatory patterns or findings. The presence or absence of MPA did not correlate with pathologic findings.

Conclusions

MPO-ANCA-positive patients with ILD do not show the typical UIP pattern as seen in patients with idiopathic pulmonary fibrosis on surgical lung biopsy.

Acute exacerbation of interstitial lung diseases secondary to systemic rheumatic diseases: a prospective study and review of the literature

Acute exacerbation (AE) is a possible manifestation of interstitial lung diseases (ILD) associated to very high mortality. It's defined as clinically significant respiratory deterioration with evidence of new widespread alveolar abnormalities on computed tomography scan. AE is better described in idiopathic pulmonary fibrosis (IPF) but also reported in ILD secondary to connective tissue diseases (CTD) and vasculitis. The main features and the real clinical impact of this severe complication in these patients are not well defined. Aim of our study was to prospectively investigate the incidence, clinical features and outcome of AE in a population of patients with ILD related to CTD and vasculitis. We consecutively enrolled all patients, with ILD secondary to rheumatic systemic diseases, referring to our multidisciplinary outpatient clinic for rare lung diseases. All patients were followed for at least 12 months (range, 12-36 months). At baseline, all patients underwent to a core set of laboratory investigations and periodically followed; data about demographic, disease onset, clinical, serological and therapeutic features were also recorded. AE occurred in 9/78 patients, with an incidence of 5.77/100 patients/year, and 5/9 patients died because of AE. The baseline value of DLCO was significantly associated to the risk of AE at Cox regression. In patients with ILD related to rheumatic systemic diseases AE can occur with an incidence similar to IPF. Rheumatologists should carefully consider this life-threatening complication as a possible natural course of all patients with ILD secondary to systemic rheumatic disease.

Interstitial lung disease with usual interstitial pneumonia pattern preceding the presentation of ANCA-associated vasculitis by 4 years: coincidence or correlation?

Initial evaluation for ANCA should be performed at diagnosis in all patients with pulmonary fibrosis; ANCA positivity will increase risk of development of vasculitis and promote further evaluation and specific monitoring http://ow.ly/hf4730kVZF8.

Renal Involvement in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

Antineutrophil cytoplasmic antibody-associated vasculitis (AAV) is the most common cause of rapidly progressive glomerulonephritis. ANCAs play an important role in the pathogenesis and diagnosis of AAV. The classic renal lesion in AAV is a pauci-immune necrotizing and crescentic glomerulonephritis. Treatment is divided into 2 phases: (1) induction of remission to eliminate disease activity and (2) maintenance of remission to prevent disease relapse. AAV patients with end-stage renal disease require modification of immunosuppressive strategies and consideration for kidney transplantation. An improved understanding of disease pathogenesis has led to new treatment strategies being tested in clinical trials.

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.

Acantholytic squamous cell carcinoma of the lung with marked lymphogenous metastases and high titers of myeloperoxidase-antineutrophil cytoplasmic antibodies: a case report

BACKGROUND

Acantholytic squamous cell carcinoma (ASQCC), histologically characterized by intercellular bridge loosening, is recognized as a rare variant of squamous cell carcinoma (SQCC). ASQCC may demonstrate a worse prognosis than conventional SQCC. Pulmonary ASQCC is particularly rare; its biological behavior and prognostic data have not been reported.

CASE PRESENTATION

We report the clinical and autopsy findings of a 71-year-old Japanese man with pulmonary ASQCC. Pulmonary lesions, suggestive of idiopathic interstitial pneumonia, were radiologically observed 3 and 6 years prior to the patient's most recent hospitalization; however, the patient did not undergo further medical examinations. Upon being discovered unconscious, the patient was admitted to our hospital. Dehydration and lower limb muscle weakness were noted, as were laboratory findings of coagulation abnormalities and renal dysfunction. Computed tomography helped confirm a 21-mm peripheral nodule in the upper left lobe of the lung, with associated swollen lymph nodes in the bilateral hilar, mediastinal, and para-aortic regions. Brain and spinal lesions, suggestive of neurological disturbances, were not found. Small cell lung carcinoma was suspected, upon admission, but high serum levels of squamous cell carcinoma antigen and cytokeratin-19 fragments were present. Therefore, advanced lung cancer, possibly SQCC, was diagnosed. The patient was treated with best supportive therapy, and died one month after admission. Hypercalcemia and high serum levels of parathyroid hormone-related protein (PTHrP) and myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA) titers were observed. Progressive renal insufficiency was absent due to improved renal function subsequent to hydration. An autopsy helped confirm the left lung tumor as an ASQCC associated with pulmonary lymphangitic carcinomatosis and multiple metastases in the lungs and lymph nodes. Skin lesions suggesting malignant tumors were absent. The metastatic lesions consisted largely of acantholytic tumor cells, and the lungs showed usual interstitial pneumonia pattern; vasculitis was absent.

CONCLUSIONS

This is the first reported case of pulmonary ASQCC resulting in an aggressive clinical course, with marked lymphogenous metastases and PTHrP-associated hypercalcemia. The high serum MPO-ANCA titers were clinicopathologically insignificant, but may have been related to the pulmonary interstitial lesion. Pulmonary ASQCC represents a highly malignant subset of lung cancer.

Idiopathic Interstitial Pneumonia as a Possible Cause of Antineutrophil Cytoplasmic Antibody-Associated Vasculitis: A Case Report

There are conflicting data to date on the causal relationship between idiopathic interstitial pneumonia and antineutrophil cytoplasmic antibody (ANCA): (1) myeloperoxidase-ANCA may play a pathogenetic role in pulmonary fibrosis, or (2) pulmonary fibrosis may induce production of the antibody. In this article, we describe a case of an elderly female patient with microscopic polyangiitis that developed after positive conversion of myeloperoxidase-ANCA during the course of idiopathic interstitial pneumonia. Our experience as well as similar case reports may suggest that idiopathic interstitial pneumonia may induce production of ANCAs and even ANCA-associated vasculitis.

Muscle weakness as a presenting symptom in ANCA-associated vasculitis

Muscle weakness is rarely a presenting symptom of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), although the disease frequently involves the lungs, skin, neurons, and kidneys. Here we describe a case of AAV presenting with muscle weakness in which only muscle biopsy could confirm the diagnosis. The literature review, including three similar cases, suggested that patients with ANCA-associated muscle vasculitis likely had myalgia, normal levels of creatine kinase, pulmonary fibrosis, rheumatoid factor, and muscle edema on MRI.

Pulmonary Involvement in Antineutrophil Cytoplasmic Antibodies (ANCA)-associated Vasculitis: The Influence of ANCA Subtype

OBJECTIVE

To describe pulmonary involvement at time of diagnosis in antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV), as defined by computed tomography (CT).

METHODS

Patients with thoracic CT performed on or after the onset of AAV (n = 140; 75 women; granulomatosis with polyangiitis, n = 79; microscopic polyangiitis MPA, n = 61) followed at a tertiary referral center vasculitis clinic were studied. Radiological patterns of pulmonary involvement were evaluated from the CT studies using a predefined protocol, and compared to proteinase 3 (PR3)-ANCA and myeloperoxidase (MPO)-ANCA specificity.

RESULTS

Of the patients, 77% had an abnormal thoracic CT study. The most common abnormality was nodular disease (24%), of which the majority were peribronchial nodules, followed by bronchiectasis and pleural effusion (19%, each), pulmonary hemorrhage and lymph node enlargement (14%, each), emphysema (13%), and cavitating lesions (11%). Central airways disease and a nodular pattern of pulmonary involvement were more common in PR3-ANCA-positive patients (p < 0.05). Usual interstitial pneumonitis (UIP) and bronchiectasis were more prevalent in MPO-ANCA-positive patients (p < 0.05). Alveolar hemorrhage, pleural effusion, lymph node enlargement, and pulmonary venous congestion were more frequent in MPO-ANCA-positive patients.

CONCLUSION

Pulmonary involvement is frequent and among 140 patients with AAV who underwent a thoracic CT study, almost 80% have pulmonary abnormalities on thoracic CT. Central airway disease occurs exclusively among patients with PR3-ANCA while UIP were mainly seen in those with MPO-ANCA. These findings may have important implications for the investigation, management, and pathogenesis of AAV.

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.

Myeloperoxidase Anti-Neutrophil Cytoplasmic Antibody-Positive Interstitial Pneumonia Associated with Granulomatosis with Polyangiitis Diagnosed by Surgical Lung Biopsy

Granulomatosis with polyangiitis (GPA) is a rare systemic vasculitis that often involves the lung. However, interstitial pneumonia (IP) is rarely seen in GPA patients. We herein report 3 cases of IP associated with GPA diagnosed by surgical lung biopsy. High-resolution CT showed uniform subpleural reticular opacity with traction bronchiectasis. Biopsies from all 3 patients revealed neutrophilic capillaritis, microabscesses with giant cells, and coexisting histological findings of usual IP pattern or fibrosing nonspecific IP pattern. All 3 patients had elevated levels of serum myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA), but not proteinase 3-ANCA. We diagnosed GPA and treated with corticosteroid and cyclophosphamide. Follow-up CT showed improvement of the lesions in all patients. Surgical lung biopsy specimens which revealed GPA enabled us to conduct the most suitable therapy. This report indicates the importance of surgical lung biopsy for differentiating idiopathic IPs from GPA-associated IP and suggests a relationship between MPO-ANCA and IP in GPA.

Clinical features of usual interstitial pneumonia with anti-neutrophil cytoplasmic antibody in comparison with idiopathic pulmonary fibrosis

BACKGROUND AND OBJECTIVE

Myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA) is occasionally positive in patients with usual interstitial pneumonia (UIP). However, the differences from idiopathic pulmonary fibrosis (IPF/UIP) have not been well documented. We aimed to clarify the clinical, radiological and pathological features of UIP associated with MPO-ANCA (ANCA/UIP).

METHODS

We retrospectively reviewed the medical records of 12 consecutive ANCA/UIP patients not manifesting microscopic polyangiitis and 108 IPF/UIP patients with no autoantibodies, both diagnosed by surgical lung biopsy.

RESULTS

There was no significant difference in clinical background, laboratory results and pulmonary function tests between ANCA/UIP patients and IPF/UIP patients except for the percentage of bronchoalveolar lavage neutrophils. HRCT showed subpleural reticulation in both groups. Increased attenuation around honeycombing and cysts was significantly observed in ANCA/UIP. Pathologically, ANCA/UIP had more prominent inflammatory cell infiltration, lymphoid follicles with germinal centres and cellular bronchiolitis. During the disease course, three of 12 patients (25%) developed microscopic polyangiitis. Immunosuppressive treatment tended to be more effective in ANCA/UIP patients, and the survival time in ANCA/UIP patients tended to be longer than those with IPF/UIP.

CONCLUSION

ANCA/UIP may be distinguishable from IPF/UIP with a combination of HRCT findings of increased attenuation around honeycombing and cysts and some of the characteristic pathological findings. In contrast to IPF/UIP, immunosuppressive treatment could be a therapeutic option for ANCA/UIP.