Interstitial Pneumonia With Autoimmune Features (IPAF)

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.

Respiratory involvement in connective tissue diseases

Pulmonary involvement is doubtless one the most fatal organ manifestations of the autoimmune rheumatic diseases (ARD) and involves the parenchyma, the vessels, the respiratory system itself, but also the muscles and the pleura. Close and regular screening assessments, identification of risk factors, clinical signs associated with the existence of lung disease should alarm the involved physicians treating these patients. The accurate classification is essential, as different treatment options are nowadays available. Pulmonary manifestations of ARD will be analyzed in this review article with special emphasis on interstitial lung disease and pulmonary hypertension.

Diagnostic Approaches for Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrosing interstitial pneumonia with a very poor prognosis. Accurate diagnosis of IPF is essential for good outcomes but remains a major medical challenge due to variability in clinical presentation and the shortcomings of existing diagnostic tests. Medical history collection is the first and most important step in the IPF diagnosis process; the clinical probability of IPF is high if the suspected patient is 60 years or older, male, and has a history of cigarette smoking. Systemic assessment for connective tissue disease is essential in the initial evaluation of patients with suspected IPF to identify potential causes of interstitial lung disease (ILD). Radiologic examination using high-resolution computed tomography plays a pivotal role in the evaluation of patients with ILD, and prone and expiratory computed tomography images can be considered. If additional tests such as surgical lung biopsy or transbronchial lung cryobiopsy are needed, transbronchial lung cryobiopsy should be considered as an alternative to surgical lung biopsy in medical centers with experience performing this procedure. Diagnosis through multidisciplinary discussion (MDD) is strongly recommended as MDD has become the cornerstone for diagnosis of IPF, and the scope of MDD has expanded to monitoring of disease progression and suggestion of appropriate treatment options.

FibroVit-Vision transformer-based framework for detection and classification of pulmonary fibrosis from chest CT images

Pulmonary Fibrosis (PF) is an immedicable respiratory condition distinguished by permanent fibrotic alterations in the pulmonary tissue for which there is no cure. Hence, it is crucial to diagnose PF swiftly and precisely. The existing research on deep learning-based pulmonary fibrosis detection methods has limitations, including dataset sample sizes and a lack of standardization in data preprocessing and evaluation metrics. This study presents a comparative analysis of four vision transformers regarding their efficacy in accurately detecting and classifying patients with Pulmonary Fibrosis and their ability to localize abnormalities within Images obtained from Computerized Tomography (CT) scans. The dataset consisted of 13,486 samples selected out of 24647 from the Pulmonary Fibrosis dataset, which included both PF-positive CT and normal images that underwent preprocessing. The preprocessed images were divided into three sets: the training set, which accounted for 80% of the total pictures; the validation set, which comprised 10%; and the test set, which also consisted of 10%. The vision transformer models, including ViT, MobileViT2, ViTMSN, and BEiT were subjected to training and validation procedures, during which hyperparameters like the learning rate and batch size were fine-tuned. The overall performance of the optimized architectures has been assessed using various performance metrics to showcase the consistent performance of the fine-tuned model. Regarding performance, ViT has shown superior performance in validation and testing accuracy and loss minimization, specifically for CT images when trained at a single epoch with a tuned learning rate of 0.0001. The results were as follows: validation accuracy of 99.85%, testing accuracy of 100%, training loss of 0.0075, and validation loss of 0.0047. The experimental evaluation of the independently collected data gives empirical evidence that the optimized Vision Transformer (ViT) architecture exhibited superior performance compared to all other optimized architectures. It achieved a flawless score of 1.0 in various standard performance metrics, including Sensitivity, Specificity, Accuracy, F1-score, Precision, Recall, Mathew Correlation Coefficient (MCC), Precision-Recall Area under the Curve (AUC PR), Receiver Operating Characteristic and Area Under the Curve (ROC-AUC). Therefore, the optimized Vision Transformer (ViT) functions as a reliable diagnostic tool for the automated categorization of individuals with pulmonary fibrosis (PF) using chest computed tomography (CT) scans.

Unclassifiable interstitial lung disease and autoimmunity: Towards IPAF in children?

INTRODUCTION

Interstitial pneumonia with autoimmune features (IPAF) has been defined for adults with interstitial lung disease (ILD) and autoimmunity who do not meet the criteria for a specific connective tissue disease (CTD). We aimed to determine whether IPAF criteria could apply to children.

METHODS

We retrospectively studied patients with ILD and autoimmunity followed at Necker Hospital between 2008 and 2019. Children were classified according to specific CTD and IPAF criteria. The epidemiology and course of the disease were studied according to the final diagnosis.

RESULTS

Among 27 patients, 6 fulfilled the criteria for IPAF and represented 4.5% of all patients with ILD during the study period. Other diagnoses included juvenile dermatomyositis (30%), overlap syndromes (19%), systemic lupus erythematosus (15%), systemic sclerosis (7%), mixed CTD (4%), and rheumatoid arthritis (4%). IPAF patients were more frequently boys versus CTD-ILD patients (67% vs. 14%, p = .02). Two patients had severe respiratory distress that led to death for one of them. The course was favorable for the others, with a good response to steroids. The course tended to be more favorable for IPAF patients than for those with CTD-ILD (0% lung fibrosis in the IPAF group vs. 43% in the CTD-ILD group, p = .07).

CONCLUSION

We confirmed the existence of IPAF in children. Its prevalence was lower than in adults but comparable to that found for other pediatric series. Boys were more highly represented than in CTD-ILD. The course was favorable for most cases. Larger and more prospective studies are needed to confirm these results.

Nailfold capillaroscopy findings of interstitial pneumonia with autoimmune features

BACKGROUND/AIMS

We evaluated nailfold capillaroscopy (NFC) of interstitial pneumonia with autoimmune features (IPAF) and compared it with that of patients with connective tissue disease-interstitial lung disease (CTD-ILD) and idiopathic interstitial pneumonia (IIP).

METHODS

Patients with newly diagnosed as ILD were evaluated using NFC. Baseline demographic, clinical, serological, and high-resolution CT findings were collected. NFC was semi-quantitatively scored with six domains ranging from 0 to 18. In addition, the overall patterns (scleroderma/non-scleroderma patterns) were determined.

RESULTS

A total of 81 patients (31 with CTD-ILD, 18 with IPAF, and 32 with IIP) were included. The non-specific interstitial pneumonia pattern was the most common ILD pattern in the CTD-ILD and IPAF groups, whereas the usual interstitial pneumonia pattern was the most common in the IIP group. The semi-quantitative score of the CTD-ILD group was higher than that of the IPAF or IIP groups (5.8 vs 4.2 vs 3.0, p < 0.001, respectively). Giant capillaries and haemorrhages were more frequently present in the CTD-ILD and IPAF groups than in the IIP group. A scleroderma pattern was present in 27.8% of the IPAF group, whereas none of the IIP patients showed a scleroderma pattern.

CONCLUSION

NFC findings may be useful in classifying patients with ILD into CTD-ILD/IPAF/IIP.

Myositis interstitial lung disease and autoantibodies

The aim of this review is to examine and evaluate published literature associated with idiopathic inflammatory myopathies (IIM) and interstitial lung disease (ILD) based on myositis specific autoantibodies (MSA) and the potential clinical significance of each autoantibody subtype for the practicing clinician. The review is a comprehensive search of literature published in PubMed from the year 2005 and onward coinciding with the surge in the discovery of new MSAs. Additionally, we comment on recommended multidisciplinary longitudinal care practices for patients with IIM-ILD with regard to imaging and other testing. Treatment is not covered in this review.

Clinical and Serological Characteristics of a Monocentric Cohort of Patients Affected by Interstitial Pneumonia with Autoimmune Features (IPAF)

Introduction

Interstitial lung diseases (ILDs) are diseases characterised by excessive deposition of collagen matrices in the pulmonary interstitium. Some of them are considered idiopathic (idiopathic pulmonary fibrosis - IPF), others are related to known pathologies such as connective tissue diseases (CTDs-ILD). Patient affected by ILD and features referable to CTD, not satisfying CTD criteria, are called Interstitial pneumonia with autoimmune features (IPAF) patients.

Objective

The aim of this report was to investigate clinical and serologic features of a monocentric cohort of patients with IPAF. Another objective was to describe the autoantibody profile, clinical features, High Resolution Computerised Tomography (HRCT) and Nailfold Video Capillaroscopy (NVC) patterns.

Methods

36 IPAF patients were consecutively enrolled. Clinical, serological, and morphological features were collected.

Results

36 consecutive IPAF patients were enrolled from January 2021 to January 2022. Raynaud's phenomenon was the most frequent symptom identified. We also described other signs and symptoms not included in IPAF criteria. 36,1% of patients demonstrated a Usual Interstitial Pneumonia (UIP) pattern by HRCT. Pulmonary arterial pressure estimation (PAPs) resulted elevated (≥ 25 mmHg) in 6 patients. Antinuclear antibodies (ANA) ≥ 1/80 was the most frequent autoantibody, followed by anti-Ro, in patients with UIP pattern and Non-Specific Interstitial Pneumonia (NSIP) pattern at HRCT. NVC highlighted non-specific microangiopathy as the most common pattern especially in UIP patients.

Conclusions

This paper may contribute to stimulate the interest in better characterisation of clinical, serologic, and instrumental features for IPAF patients by redefining IPAF classification criteria in order to treat them as best as possible.

Challenges in the diagnosis of idiopathic pulmonary fibrosis: the importance of a multidisciplinary approach

INTRODUCTION

The diagnosis of Idiopathic pulmonary fibrosis (IPF) requires the careful exclusion of secondary causes of interstitial lung disease (ILD), and the collaboration among different specialists is considered paramount to establish a diagnosis with high diagnostic confidence. The multidisciplinary discussion (MDD) has assumed an increasing importance over the years in the different phases of the IPF diagnostic work-up.

AREAS COVERED

The role of MDD in the diagnosis and management of IPF will be described. Practical insights will be provided into how and when to perform MDD based on the available scientific evidence. Current limitations and future perspectives will be discussed.

EXPERT OPINION

In the absence of high diagnostic confidence, agreement between different specialists during MDD is recognized as a surrogate indicator of diagnostic accuracy. Often, despite a lengthy evaluation, the diagnosis remains unclassifiable in a significant percentage of patients. MDD therefore appears to be pivotal in attaining an accurate diagnosis of ILDs. The discussion among different specialists can also include other specialists, such as rheumatologists and thoracic surgeons, in addition to the core group of pulmonologists, radiologists, and pathologists. Such discussions can allow greater diagnostic accuracy and have important effects on management, pharmacologic therapies, and prognosis.

[Interstitial Lung Disease]

Diffuse interstitial lung diseases (ILD) are a heterogeneous group of respiratory disorders that are usually classified together because they have similar clinical, radiological, physiological or pathological manifestations. In the last decade there have been important scientific advances in the study of these entities, which has led to a better understanding of their pathophysiology and to the appearance of treatments that have brought about a paradigm shift in the disease. This document presents a series of questions and answers on ILD, with special emphasis on the most relevant changes in terms of pathophysiology, diagnosis, and treatment.

Recurrent Exacerbations and Evolution into Polymyositis in a Patient with Interstitial Pneumonia with Autoimmune Features: A Case Report and Literature Review

Interstitial pneumonia with autoimmune features (IPAF) is a new disease entity proposed in 2015. Numerous questions regarding IPAF require clarification, including diagnostic criteria, standard managements for stable disease and exacerbation, and prognosis. We report a case of a 67-year-old Asian woman who presented with progressive dyspnea. Chest computed tomography (CT) scans revealed nonspecific interstitial pneumonia. Serologic testing indicated positive anti-Jo-1 without presence of extrathoracic manifestations. An IPAF diagnosis was made after a multidisciplinary discussion. The patient experienced a severe exacerbation requiring mechanical ventilation, and she was successfully salvaged with methylprednisolone pulse therapy and single-dose cyclophosphamide. During the one-year follow-up, she reported bilateral leg muscle weakness with noticeably elevated serum creatine kinase, suggesting polymyositis. The development of malignancy was also noted 15 months after the initial presentation, and the patient eventually died. This report demonstrated successful salvage treatment with glucocorticoid pulse therapy for IPAF with acute exacerbation. However, the maintenance therapy failed to control disease progression. The treatment strategies for exacerbation and stable disease in IPAF remain unknown and need further studies. Given the high risk of evolution into a defined connective tissue disease (CTD), regular evaluation of the clinical features and biomarkers of CTDs is essential for patients with IPAF.

Prognostication of progressive pulmonary fibrosis in connective tissue disease-associated interstitial lung diseases: A cohort study

Background

Connective tissue diseases-associated interstitial lung disease (CTD-ILD) is a heterogeneous condition that impairs quality of life and is associated with premature death. Progressive pulmonary fibrosis (PPF) has been identified as an important risk factor for poor prognosis. However, different criteria for PPF are used in clinical studies, which may complicate comparison between trials and translation of study findings into clinical practice.

Methods

This is a retrospective single center study in patients with CTD-ILD. The prognostic relevance of PPF definitions, including INBUILD, ATS/ERS/JRS/ALAT 2022, and simplified progressive fibrosing (simplified PF) criteria, were examined in this cohort and validated in the other reported Dutch CTD-ILD cohort.

Results

A total of 230 patients with CTD-ILD were included and the median follow-up period was six (3-9) years. Mortality risk was independently associated with age (adjusted HR 1.07, p < 0.001), smoking history (adjusted HR 1.90, p = 0.045), extent of fibrosis on high-resolution computed tomography (HRCT) at baseline (adjusted HR 1.05, p = 0.018) and baseline DLCO (adjusted HR 0.97, p = 0.013). Patients with regular pulmonary function tests in the first 2 years (adjusted HR 0.42, p = 0.002) had a better survival. The prognostic relevance for survival was similar between the three PPF criteria in the two cohorts.

Conclusion

Higher age, smoking, increased extent of fibrosis and low baseline DLCO were associated with poor prognosis, while regular pulmonary function evaluation was associated with better survival. The INBUILD, ATS/ERS/JRS/ALAT 2022, and simplified PF criteria revealed similar prognostication.

Interstitial disease associated with connective tissue disease and vasculitis

Systemic autoimmune diseases comprise a complex, heterogeneous group of entities. Noteworthy among the pulmonary complications of these entities is interstitial involvement, which manifests with the same radiopathologic patterns as in idiopathic interstitial pneumonia. High-resolution computed tomography is the gold-standard imaging technique; it enables us to identify and classify the disease and to determine its extent, providing useful information about the prognosis. In this group of processes, the most common pattern of presentation is nonspecific interstitial pneumonia. It is essential for radiologists to work together in collaboration with other specialists to reach the correct diagnosis and enable appropriate, integrated treatment.

Prevalence and clinical associations of myositis antibodies in a large cohort of interstitial lung diseases

Background

Serologic testing for autoantibodies is recommended in interstitial lung diseases (ILDs), as connective tissue diseases (CTDs) are an important secondary cause. Myositis antibodies are associated with CTD-ILD, but clinical associations with other ILDs are unclear. In this study, associations of myositis antibodies in various ILDs were evaluated.

Methods

1463 ILD patients and 116 healthy subjects were screened for myositis antibodies with a line-blot assay on serum available at time of diagnosis. Additionally, bronchoalveolar lavage fluid (BALf) was analysed.

Results

A total of 394 patients demonstrated reactivity to at least one antibody, including anti-Ro52 (36.0%), anti-Mi-2β (17.3%) and anti-Jo-1 (10.9%). Anti-Jo-1 (OR 6.4; p<0.100) and anti-Ro52 (OR 6.0; p<0.001) were associated with CTD-ILD. Interestingly, anti-Mi-2β was associated with idiopathic pulmonary fibrosis (IPF; OR 5.3; p = 0.001) and hypersensitivity pneumonitis (HP; OR 5.9; p<0.001). Furthermore, anti-Mi-2β was strongly associated with a histological usual interstitial pneumonia (UIP) pattern (OR 6.5; p < 0.001). Moreover, anti-Mi-2β reactivity was identified in BALf and correlated with serum anti-Mi-2β (r = 0.64; p = 0.002). No differences were found in survival rates between ILD patients with and without serum Mi-2β reactivity (hazard ratio 0.835; 95% CI 0.442–1.575; p = 0.577).

Conclusion

In conclusion, novel associations of antibody Mi-2β with fibrotic ILD were found. Furthermore, serum anti-Mi-2β was associated with a histological UIP pattern and presence of anti-Mi-2β in BALf. Possibly, anti-Mi-2β could be implemented as a future diagnostic biomarker for fibrotic ILD.

Detection of interstitial pneumonia with autoimmune features and idiopathic pulmonary fibrosis are enhanced by involvement of matrix metalloproteinases levels and clinical diagnosis

BACKGROUND

Higher detection of interstitial pneumonia with autoimmune features (IPAF), and idiopathic pulmonary fibrosis (IPF), has significant diagnostic and therapeutic implications. Some matrix metalloproteinases (MMPs) have become reliable diagnostic biomarkers in IPAF and IPF in previous studies, yet relevant reliability remains to be recognized.

MATERIALS AND METHODS

In this study, 36 ILDs patients, including 31 IPAF patients (Mean ± SD, 50.20 ± 5.10 years; 16 [51.6%] females) and five IPF patients (Mean ± SD, 61.20 ± 6.73 years; one [20.0%] females) were retrospectively enrolled. Serial serum samples were collected from patients with IPAF and IPF between January 2019 and December 2020. Notably, Serum MMPs levels were measured by U-PLEX Biomarker Group 1(Human) Multiplex Assays (MSD, USA).

RESULTS

A combination of MMPs and combinatorial biomarkers was strongly associated with clinical subjects in this study (AUC, 0.597 for Stability vs. Improvement and 0.756 for Stability vs. Exacerbation). Importantly, the AUC of MMP-12 reaches 0.730 (p < 0.05, Stability AUC vs. Improvement AUC) while MMP-13 reaches 0.741 (p < 0.05, Stability AUC vs. Exacerbation AUC) showed better performance than other MMPs in two comparisons.

CONCLUSIONS

Clinical risk factors and MMPs are strongly associated with either stratification of the disease of progression of IPAF or in two IPAF and IPF independent cohorts. To our knowledge, this is the first to illustrate that MMP-12 and MMP-13 may be expected to become typical promising biomarkers in Improvement - IPAF and Exacerbation - IPAF, respectively.

Management of Connective Tissue Disease-related Interstitial Lung Disease

Purpose of Review

This review aims to collate current evidence on the screening, diagnosis, and treatment of various connective tissue disease (CTD)–associated interstitial lung diseases (CTD-ILD) and present a contemporary framework for the management of such patients. It also seeks to summarize treatment outcomes including efficacy and safety of immunosuppressants, anti-fibrotics, and stem cell transplantation in CTD-ILD.

Recent Findings

Screening for ILD has been augmented by the use of artificial intelligence, ultra-low dose computerized tomography (CT) of the chest, and the use of chest ultrasound. Serum biomarkers have not found their way into clinical practice as yet. Identifying patients who need treatment and choosing the appropriate therapy is important to minimize the risk of therapy-related toxicity. The first-line drugs for systemic sclerosis (SSc) ILD include mycophenolate and cyclophosphamide. Nintedanib, an anti-fibrotic tyrosine kinase inhibitor, is approved for use in SSc-ILD. The US Food and Drug Administration (FDA) has recently approved tocilizumab subcutaneous injection for slowing the rate of decline in pulmonary function in adult patients with SSc-ILD. Autologous stem cell transplantation may have a role in select cases of SSc-ILD.

Summary

CTD-ILD is a challenging area with diverse entities and variable outcomes. High-resolution CT is the investigative modality of choice. Treatment decisions need to be individualized and are based on patient symptoms, lung function, radiologic abnormalities, and the risk of disease progression. Precision medicine may play an important role in determining the optimal therapy for an individual patient in the future.

Interstitial pneumonia with autoimmune features: challenges and controversies

The presence of clinical, serological and/or radiological features suggestive, but not confirmatory, of a defined connective tissue disease in patients with interstitial lung disease is a relatively frequent occurrence. In 2015, the European Respiratory Society and the American Thoracic Society proposed classification criteria for the interstitial pneumonia with autoimmune features (IPAF) research entity to capture such patients in a standardised manner, with the intention of nurturing clinical research. This initiative resulted in the publication of several series of IPAF patients, with significant variation between cohorts in clinical characteristics, outcome and the application of IPAF criteria in patient selection. From this increasing body of published work, it has become apparent that revision of IPAF criteria is now required in order to justify the eventual designation of IPAF as a standalone diagnostic term, as opposed to a provisional entity put forward as a basis for clinical research. This review covers the current state of IPAF, conclusions that can and cannot be drawn from the IPAF evidence base, and ongoing uncertainties that require further expert group consideration.

Predictors for progressive fibrosis in patients with connective tissue disease associated interstitial lung diseases

BACKGROUND

Connective tissue disease associated interstitial lung disease (CTD-ILD) is associated with decreased quality of life and high mortality risk. Outcome and treatment response is unpredictable. This study aimed to identify clinical predictors for CTD-ILD with poor outcome.

METHODS

We performed a retrospective single centre cohort study in outpatients with CTD-ILD seen between 2004 and 2018. Clinical and biochemical data, pulmonary function tests (PFT) and high-resolution computed tomography (HRCT) results were analysed. Overall survival and progressive fibrosing ILD (PF-ILD, defined as a significant deterioration of PFT or HRCT) after two years of follow-up were assessed.

RESULTS

In total, 150 patients with CTD-ILD were included. Thirty (20%) deaths occurred during a median follow-up of 40 months (IQR 27.3-60.8), which were attributed to pulmonary infection in six (4%), respiratory failure due to PF-ILD in ten (7%) and due to other causes in fourteen patients. PF-ILD occurred in 76 (50.7%) patients and was associated with poor overall survival (adjusted HR 5.73, 95%CI 1.17-28.11). Age, smoking, C-reactive protein, and steroid-use were independently associated with increased mortality risk as well. Furthermore, patients with diabetes mellitus (adjusted OR 4.52, 95%CI 1.10-18.51), steroid-use (adjusted OR 2.26, 95%CI 1.04-4.93), and a fibrotic HRCT pattern at baseline (adjusted OR 3.11, 95%CI 1.15-8.38) had a higher risk of PF-ILD.

CONCLUSION

PF-ILD is associated with increased mortality in patients with CTD-ILD. Patients with a fibrotic HRCT pattern at baseline, diabetes mellitus and steroid-use have a higher risk of developing PF-ILD.

Clinical spectrum of children with interstitial pneumonia with autoimmune features

BACKGROUND

Interstitial pneumonia with autoimmune features (IPAF) is a term used to describe adult patients with interstitial lung disease (ILD) who display some clinical or serological features of autoimmune diseases and who do not meet the full criteria for a specific connective tissue disease (CTD). The aim of this study was to define the demographic, clinical, radiologic, serologic and histopathologic features and assess treatment in children with IPAF.

METHODS

This retrospective cohort study was conducted at a tertiary referral pediatric pulmonology center between January 2010 and August 2020. Children with proven interstitial pneumonia with no known etiologies were evaluated for IPAF according to European Respiratory Society/American Thoracic Society research statement of IPAF.

RESULTS

Among 132 children with ILD, 17 patients were evaluated in detail for IPAF criteria and six patients were further diagnosed as having IPAF. The incidence of IPAF in our patients with ILD was 4.5%. Four of these patients were female. The median age at the time of ILD diagnosis was 10.5 years. The most common initial symptom was shortness of breath, and the most common physical examination sign was crackles in both lungs. Steroid therapy was given to all patients and four patients received other immunosuppressive agents for steroid sparing. Two of those patients died because of respiratory insufficiency during the follow-up.

CONCLUSION

Children with interstitial pneumonia and certain clinical, serologic, and/or morphologic features should raise suspicion for the presence of an underlying systemic autoimmune disease. IPAF is also seen in children and should be categorized in chILD classifications.

Interstitial Lung Abnormalities: State of the Art

The clinical importance of interstitial lung abnormality (ILA) is increasingly recognized. In July 2020, the Fleischner Society published a position paper about ILA. The purposes of this article are to summarize the definition, existing evidence, clinical management, and unresolved issues for ILA from a radiologic standpoint and to provide a practical guide for radiologists. ILA is a common incidental finding at CT and is often progressive and associated with worsened clinical outcomes. The hazard ratios for mortality range from 1.3 to 2.7 in large cohorts. Risk factors for ILA include age, smoking status, other inhalational exposures, and genetic factors (eg, gene encoding mucin 5B variant). Radiologists should systematically record the presence, morphologic characteristics, distribution, and subcategories of ILA (ie, nonsubpleural, subpleural nonfibrotic, and subpleural fibrotic), as these are informative for predicting progression and mortality. Clinically significant interstitial lung disease should not be considered ILA. Individuals with ILA are triaged into higher- and lower-risk groups depending on their risk factors for progression, and systematic follow-up, including CT, should be considered for the higher-risk group. Artificial intelligence-based automated analysis for ILA may be helpful, but further validation and improvement are needed. Radiologists have a central role in clinical management and research on ILA.

Clinical significance of anti-NOR90 antibodies in systemic sclerosis and idiopathic interstitial pneumonia

OBJECTIVE

Anti-NOR90 antibodies are usually found in patients with systemic sclerosis (SSc); however, their clinical relevance remains obscure. We developed an enzyme-linked immunosorbent assay (ELISA) for measuring them to investigate the clinical features of patients with anti-NOR90 antibodies.

METHODS

Serum samples from 1,252 patients with various conditions from Nagoya University Hospital and 244 patients with idiopathic interstitial pneumonia (IIP) from Tosei General Hospital were included. Anti-NOR90 antibodies were assayed by an ELISA using the recombinant protein produced by in vitro transcription/translation.

RESULTS

Five (0.4%) patients in the Nagoya University Hospital cohort had anti-NOR90 antibodies. One patient with diffuse cutaneous SSc, 3 with limited cutaneous SSc, and 1 with Raynaud's disease were positive for anti-NOR90 antibodies. Anti-NOR90 antibodies were found more frequently in patients with systemic scleroderma-spectrum disorders (SSDs) than without SSDs (5/316 vs. 0/936, P<0.00101) and were found more frequently in patients with SSc than without SSc (4/249 vs. 0/528, P<0.0104) in the systemic autoimmune rheumatic diseases cohort. Three of the 4 anti-NOR90-positive SSc patients had interstitial lung disease (ILD), and 2 of those 4 had cancer. Three (1.2%) patients in the Tosei General Hospital cohort had anti-NOR90 antibodies. All 3 of the anti-NOR90-positive IIP patients had gastrointestinal tract involvement, and 2 of those 3 had cancer or skin lesions observed in SSc.

CONCLUSIONS

Although anti-NOR90 antibodies are rarely found in clinics, our ELISA is useful for their detection. Further studies are needed to confirm the association of anti-NOR90 antibodies with ILD and cancer in SSc and IIP patients.

Unclassifiable, or simply unclassified interstitial lung disease?

PURPOSE OF REVIEW

Unclassifiable interstitial lung disease (ILD) comprises a subset of ILDs which cannot be classified according to the current diagnostic framework. This is a likely a heterogeneous group of diseases rather than a single entity and it is poorly defined and hence problematic for prognosis and therapy.

RECENT FINDINGS

With increased treatment options for progressive fibrosing ILD it is increasingly relevant to correctly categorise ILD.

SUMMARY

This review article will summarise the definition and reasons for a diagnosis of unclassifiable ILD, the current management options and possible future approaches to improve diagnosis and differentiation within this broad subset. Finally, we will describe the implications of the labelling of unclassifiable ILD in clinical practice and research and whether the term 'unclassified' should be used, implying a less definitive diagnosis.

Immune recognition of lysyl-tRNA synthetase and isoleucyl-tRNA synthetase by anti-OJ antibody-positive sera

OBJECTIVE

Anti-aminoacyl-tRNA synthetase (anti-ARS) antibodies are useful for identifying a clinical subset of patients with idiopathic inflammatory myopathies (IIMs). Anti-OJ antibodies, which recognize multi-enzyme synthetase complexes including isoleucyl-tRNA synthetase (IARS) and lysyl-tRNA synthetase (KARS), are among the anti-ARS antibodies. Although testing antibodies to other ARSs have been used clinically, no validated immunoassays for detecting anti-OJ antibodies are available. We aimed to establish an anti-OJ ELISA.

METHODS

Serum samples were collected from 279 patients with IIMs and 22 patients with idiopathic interstitial pneumonia. Sixty-four of the samples that had been confirmed to be negative for anti-OJ by standard immunoprecipitation were used as the negative control, and 12 anti-OJ-positive reference sera were used as the positive control. Antibodies to IARS and KARS were assayed by ELISA using biotinylated recombinant proteins generated by in vitro transcription/translation.

RESULTS

The anti-OJ-positive sera strongly reacted with the KARS and IARS recombinant proteins in ELISA. Although all 12 reference sera were positive in the anti-KARS ELISA, 4 of the 64 anti-OJ-negative sera were also weakly positive. The sensitivity and the specificity were 100% and 93.8%, respectively. Since our anti-KARS ELISA performed well, showing a high agreement with the results for immunoprecipitation (Cohen's κ > 0.8), the remaining 237 samples were also tested. Thirteen anti-KARS-positive sera were newly found by ELISA, all of which were anti-OJ positive by immunoprecipitation.

CONCLUSION

Immunoassays for detecting anti-OJ antibodies using KARS and IARS recombinant proteins were developed. Our ELISAs performed well, with very high agreement of the results by immunoprecipitation and can be applied to the first reliable, easy-to-use measurement assays for anti-OJ antibodies.

Clinical, radiologic and serologic profile of patients with interstitial pneumonia with autoimmune features: a cross-sectional study

The current study aimed to characterize patients from a rheumatology referral center in north India, who satisfied the definition of interstitial pneumonia with autoimmune features (IPAF) as given by the American Thoracic Society and European Respiratory Society (ATS/ERS) consensus committee in 2015. Thirty-five adult patients aged 18 years and above, fulfilling the 2015 ATS/ERS criteria for IPAF were included in the study. The clinical and immunological profile, and radiologic findings on high-resolution computerized tomography thorax were noted. Antinuclear antibody (ANA) by indirect immunofluorescence at 1:320 titer and myositis-specific antibody (MSA) assays were performed. Non-parametric tests were used to compare variables between groups. The study cohort included predominantly female patients with a mean age of 50.6 ± 13 years and mean duration of disease of 38.8 ± 28.4 months. Majority of patients (49%) fulfilled the morphologic and serologic domains as per the IPAF consensus criteria and 31% patients had features in all three domains. Non-specific interstitial pneumonia was the most common pattern observed in 77% patients. Raynaud’s phenomenon and inflammatory arthritis were the predominant autoimmune features. Pulmonary arterial hypertension was documented in 60% of patients on echocardiography. Positive ANA at 1:320 dilution was present in all 26 patients tested, whereas extractable nuclear antigen and MSA assays detected autoantibodies in 49% and 51% of patients respectively. IPAF predominantly affected females in the age group of 50 years and above, with varied autoimmune manifestations and autoantibody profile.

Successful treatment of interstitial pneumonia with autoimmune features using rituximab as salvage therapy

Interstitial pneumonia with autoimmune features is a complex and heterogeneous research classification without clear management and should be discussed on a case-by-case basis in a pluridisciplinary way. Rituximab could be used for severe lung involvement. The coronavirus crisis can hide other pathologies in such a way that a diagnosis can be overlooked.

Krebs von den Lungen-6 and surfactant protein-A in interstitial pneumonia with autoimmune features

Interstitial pneumonia with autoimmune features (IPAF) is a special subtype of interstitial lung disease that has received worldwide attention. Krebs von den Lungen-6 (KL-6) and surfactant protein-A (SP-A) can be used as an important biomarker of interstitial lung disease, but its exact relationship with IPAF is poorly understood.A total of 65 IPAF patients were included in the study and were followed up for 52 weeks. The KL-6 and SP-A were evaluated by chemiluminescence enzyme immunoassay. The above indicators were tested at 2 time points, baseline (the first admission of patients) and 52 weeks. We also collected the indicators of antinuclear antibodies and rheumatoid factor. Based on high-resolution computed tomography evaluations, patients were divided into: aggravation, stable, and improvement group. At same time, 30 age-matched normal people as normal control were recruited, the same information was collected. Correlations among the groups were compared and analyzed.The KL-6 and SP-A level in IPAF patients were significantly higher than normal controls (fold increase = 11.35 and 1.39, both P < .001) and differed significantly at baseline and 52 weeks in IPAF (difference ratio = 37.7% and 21.3%, P < .05, both). There were significant differences at baseline and 52 weeks (r values of aggravation, improvement, and stable groups for KL-6 were 0.705, 0.770, and 0.344, P = .001, .001, and .163, and for SP-A the r value were 0.672, 0.375, and 0.316, P = .001, .126, and .152). In aggravation group, KL-6 and SP-A were correlated with CT scores (both P < .05). Diffusing capacity of the lung for carbon monoxide (DLCO) and forced vital capacity (FVC), % predicted showed a progressive downward trend, with a significant difference at baseline and 52 weeks in IPAF patients (difference ratio = 23.8% and 20.6%, both P < .05). There was a significant correlation between KL-6 and FVC % predicted and DLCO (both P < .05), SP-A showed negatively correlated with DLCO, but not significantly correlated with FVC % predicted (P < .05 and .47).This study demonstrated that KL-6 and SP-A can reflect disease progression, and both 2 play a key role at reflection of lung epithelial cell injury and fibrosis degree in IPAF.

NLRP3 Inflammasome and Its Critical Role in Gynecological Disorders and Obstetrical Complications

Inflammasomes, intracellular, multimeric protein complexes, are assembled when damage signals stimulate nucleotide-binding oligomerization domain receptors (NLRs). Several inflammasomes have been reported, including the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3), NLRP1, NLRP7, ice protease-activating factor (IPAF), absent in melanoma 2 (AIM2) and NLR family CARD domain-containing protein 4 (NLRC4). Among these inflammasomes, the NLRP3 inflammasome is the most well-studied in terms of structure and function. Unlike other inflammasomes that can only be activated by a finite number of pathogenic microorganisms, the NLRP3 inflammasome can be activated by the imbalance of the internal environment and a large number of metabolites. The biochemical function of NLRP3 inflammasome is to activate cysteine-requiring aspartate proteinase-1 (caspase-1), which converts pro-IL-1β and pro-IL-18 into their active forms, namely, IL-1β and IL-18, which are then released into the extracellular space. The well-established, classic role of NLRP3 inflammasome has been implicated in many disorders. In this review, we discuss the current understanding of NLRP3 inflammasome and its critical role in gynecological disorders and obstetrical complications.

[Interstitial lung disease associated with connective tissue disease]

Interstitial lung disease (ILD) is the most frequent organ manifestation in rheumatic autoimmune disease. Depending on the underlying autoimmune disease, differently pronounced affections of small airways, interstitial parenchyma, and vessels are found. The group of rheumatic autoimmune diseases mainly includes connective tissue diseases (CTDs), also known as collagen vascular diseases, such as rheumatoid arthritis (RA), systemic sclerosis, (SSc), systemic lupus erythematosus, primary Sjögren's syndrome, idiopathic inflammatory myositis (IIM), and interstitial pneumonia with autoimmune features (IPAF). Frequency and manifestations of parenchymal lung disorders are described clinically, radiologically, and morphologically in these entities. For the precise diagnosis and for the differentiation between the wide range of parenchymal disorders with known possible cause or with unknown origin, also called unclassifiable or idiopathic interstitial pneumonias (IIPs), high resolution computed tomography (HRCT) findings represent the diagnostic gold standard. A transbronchial biopsy, surgical biopsy, or cryobiopsy will be used in unclassifiable findings to confirm a definitive histological confirmation. A precise diagnosis of these ILDs is crucial since the different pathologies that encompass ILD have different therapeutic options. In this sense, the participation of a pneumologist, rheumatologist, radiologist, and pathologist become essential in the multidisciplinary evolution of ILD.

Exhaled breath analysis by use of eNose technology: a novel diagnostic tool for interstitial lung disease

INTRODUCTION

Early and accurate diagnosis of interstitial lung diseases (ILDs) remains a major challenge. Better noninvasive diagnostic tools are much needed. We aimed to assess the accuracy of exhaled breath analysis using eNose technology to discriminate between ILD patients and healthy controls, and to distinguish ILD subgroups.

METHODS

In this cross-sectional study, exhaled breath of consecutive ILD patients and healthy controls was analysed using eNose technology (SpiroNose). Statistical analyses were done using partial least square discriminant analysis and receiver operating characteristic analysis. Independent training and validation sets (2:1) were used in larger subgroups.

RESULTS

A total of 322 ILD patients and 48 healthy controls were included: sarcoidosis (n=141), idiopathic pulmonary fibrosis (IPF) (n=85), connective tissue disease-associated ILD (n=33), chronic hypersensitivity pneumonitis (n=25), idiopathic nonspecific interstitial pneumonia (n=10), interstitial pneumonia with autoimmune features (n=11) and other ILDs (n=17). eNose sensors discriminated between ILD and healthy controls, with an area under the curve (AUC) of 1.00 in the training and validation sets. Comparison of patients with IPF and patients with other ILDs yielded an AUC of 0.91 (95% CI 0.85-0.96) in the training set and an AUC of 0.87 (95% CI 0.77-0.96) in the validation set. The eNose reliably distinguished between individual diseases, with AUC values ranging from 0.85 to 0.99.

CONCLUSIONS

eNose technology can completely distinguish ILD patients from healthy controls and can accurately discriminate between different ILD subgroups. Hence, exhaled breath analysis using eNose technology could be a novel biomarker in ILD, enabling timely diagnosis in the future.

Galectin-9 regulates follicular helper T cells to inhibit humoral autoimmunity-induced pulmonary fibrosis

Interstitial pneumonia with autoimmune features (IPAF) is an unexplained disease state characterized by autoimmunity and pulmonary fibrosis. Exploring the pathogenesis of IPAF is helpful for the treatment of interstitial pneumonia and idiopathic pulmonary fibrosis. In this study, we observed that the lung Galectin-9 (Gal-9) of IPAF patients was significantly reduced, which was significantly related to lung dysfunction and abnormal humoral immunity. Moreover, an overreactive germinal center (GC) reaction in the lung lymph nodes (LNs) of Gal-9-deficient mice was found to be related to abnormally active follicular helper T cells (Tfh) cells. The lack of Gal-9 ligand in Tfh cells can lead to excessive transcriptional programming and differentiation and help GC B cells. Gal-9 deficiency caused an abnormal humoral immune response in mice, leading to excessive deposition of nonspecific autoantibodies in mice and chronic lung fibrosis. Our research reveals the important regulatory role of gal-9 in Tfh cells and a possible target for the treatment of IPAF.

Antisynthetase syndrome - much more than just a myopathy

The aim of the study was to summarize current knowledge on antisynthetase syndrome (ASS), including its epidemiology, pathogenesis, proposed so far diagnostic criteria, heterogeneity of clinical manifestations, prognostic factors and therapeutic possibilities. PubMed database was screened for "antisynthetase syndrome" OR "antisynthetase antibodies" between February and April 2020. Aminoacyl-tRNA synthetases participate in the immune system activation as antigens, but also serve chemoattractive and cytokine-resembling roles, initiating innate and adaptive pathways. Exposure to various inhaled antigens may induce the autoimmune cascade leading to ASS. NK cells with its impaired INF-y production as well as formation of NETs by neutrophils contribute to pathogenesis. The prevalence of symptoms vary significantly depending on the study with muscular, articular and pulmonary involvement being the most frequently observed. Although classified as subtype of idiopathic inflammatory myopathies, myositis may not necessarily be the prominent manifestation. Since clinical presentation is heterogeneous and symptoms can emerge gradually, ASS could be considered as a heterogeneous spectrum rather than a homogenous disease entity. The currently available classification criteria do not fully correspond with the clinical patterns of the disease. Therapy is based on glucocorticosteroids and other immunosuppressive agents. Randomized controlled trials, dedicated for patients with ASS, are needed to form treatment algorithms.

Connective tissue disease--associated interstitial lung disease: an underreported cause of interstitial lung disease in Sub-Saharan Africa

Interstitial lung disease (ILD) occurs in 15% of connective tissue disease (CTD) patients causing considerable morbidity and mortality. Data is scarce regarding its clinical characteristics and outcomes in Africa. We aim to study the frequency, clinico-radiological characteristics, and treatment outcomes of African CTD-ILD patients. A retrospective cross-sectional study of ILD among 318 CTD patients diagnosed using relevant ACR criteria at the rheumatology unit of Lagos State University Teaching Hospital (LASUTH), Lagos from 2012 to 2019. Socio-demographics, clinical features, radiological findings, and treatment outcomes were documented. Data was analyzed using SPSS version 21 with p < 0.05. The LASUTH ethics committee approved the study. Interstitial lung disease occurred in 31 (9.7%) of 318 CTD cases. Their mean age was 38.8 ± 13.3 years, range 19-68 years with 28 (90.3%) females. Proportions of CTD-ILD were Sjogren's syndrome (50%), UCTD (50%), systemic sclerosis (46.7%), MCTD (33.3%), PM/DM (25%), SLE (6.5%), and RA (2.6%). Commonest presentations were cough (93.5%) and bibasal inspiratory crackles (83.9%) with a restrictive pattern in 83.9%. Antinuclear antibody occurred in 100% and anti-ENA in 67.7%. Traction bronchiectasis (89.7%) and ground glass opacities (96.6%) were frequent HRCT findings. Treatments included pulse-dose prednisolone, cyclophosphamide, mycophenolate mofetil, pirfenidone, and rituximab. Outcomes were ambulatory oxygen therapy (12.9%) and mortality (16.1%) with 9.7% lost to follow-up. CTD-ILD is a female predominant disease occurring in 9.7% of CTD patients mostly those with Sjogren's syndrome and systemic sclerosis. Due to significant morbidity and mortality, we advocate routine ILD screening for all CTD patients including those with undifferentiated disease. Key Points: • Interstitial lung disease occurs in 9.7% of patients with underlying connective tissue disease. • Females are predominantly affected especially those with Sjogren's syndrome and systemic sclerosis. • Mortality occurs in roughly 1 in every 6 patients with CTD-ILD.

The Spectrum of Interstitial Lung Disease Associated with Autoimmune Diseases: Data of a 3.6-Year Prospective Study from a Referral Center of Interstitial Lung Disease and Lung Transplantation

Interstitial lung disease (ILD) may occur in patients with a rheumatic autoimmune disease (AD), increasing their risk of morbidity and mortality. However, little is known about the prevalence of AD in patients diagnosed with an ILD. In this prospective study, we determined the spectrum of ILD associated with AD (AD-ILD) among patients sent for assessment to a single clinic of ILD and lung transplantation from a referral center between May 2016 and December 2019. ILD diagnosis was made by pneumologists based on clinical and radiological findings and pulmonary function test abnormalities. All patients with ILD were also assessed by experienced rheumatologists. During the period of assessment, 338 patients were diagnosed with ILD. Among them, 32.8% fulfilled definitions for an AD. Most cases with AD-ILD had a diagnosis of rheumatoid arthritis (27.0%), systemic sclerosis (26.1%) or anti-synthetase syndrome (17.1%). Interestingly, 18% of the patients with AD-ILD were diagnosed as having an interstitial pneumonia with autoimmune features. Antinuclear antibodies and non-specific interstitial pneumonia were the most frequent positive autoantibodies and radiological pattern found in AD-ILD patients, respectively. In conclusion, our study indicates that a high number of ILD patients have a related AD. Consequently, close collaboration among rheumatologists and pneumologists is needed.

Diagnostic approach of fibrosing interstitial lung diseases of unknown origin

Interstitial lung diseases encompass a broad range of numerous individual conditions, some of them characterized histologically by fibrosis, especially idiopathic pulmonary fibrosis, nonspecific interstitial pneumonia, chronic hypersensitivity pneumonia, interstitial lung disease associated with connective tissue diseases, and unclassifiable interstitial lung disease. The diagnostic approach relies mainly on the clinical evaluation, especially assessment of the patient's demographics, history, smoking habits, occupational or domestic exposures, use of drugs, and on interpretation of high-quality HRCT of the chest. Imaging is key to the initial diagnostic approach, and often can confirm a definite diagnosis, particularly a diagnosis of idiopathic pulmonary fibrosis when showing a pattern of usual interstitial pneumonia in the appropriate context. In other cases, chest HRCT may orientate toward an alternative diagnosis and appropriate investigations to confirm the suspected diagnosis. Autoimmune serology helps diagnosing connective disease. Indications for bronchoalveolar lavage and for lung biopsy progressively become more restrictive, with better considerations for their discriminate value, of the potential risk associated with the procedure, and of the anticipated impact on management. Innovative techniques and genetics are beginning to contribute to diagnosing interstitial lung disease and to be implemented routinely in the clinic. Multidisciplinary discussion, enabling interaction between pulmonologists, chest radiologists, pathologists and often other healthcare providers, allows integration of all information available. It increases the accuracy of diagnosis and prognosis prediction, proposes a first-choice diagnosis, may suggest additional investigations, and often informs the management. The concept of working diagnosis, which can be revised upon additional information being made available especially longitudinal disease behaviour, helps dealing with diagnostic uncertainty inherent to interstitial lung diseases and facilitates management decisions. Above all, the clinical approach and how thoroughly the patient's history and possible exposures are assessed determine the possibility of an accurate diagnosis.