Histopathological significance of connective tissue disease-associated interstitial lung disease in transbronchial lung cryobiopsy specimens

Differentiating between idiopathic interstitial pneumonia (IIP) and secondary interstitial pneumonia, particularly connective tissue disease-associated interstitial lung disease (CTD-ILD), can be challenging histopathologically, and there may be discrepancies among pathologists. While surgical lung biopsy has traditionally been considered the gold standard for diagnosing interstitial pneumonia, the usefulness of transbronchial lung cryobiopsy (TBLC) has been reported. If TBLC could effectively distinguish between primary and secondary diseases, it would provide a less invasive option for patients. The aim of this study was to identify specific pathologic findings in TBLC specimens that could assist in distinguishing CTD-ILD from IIP. A total of 93 underwent TBLC at Tenri Hospital between 2018 and 2022. We retrospectively reviewed cases of CTD-ILD exhibiting a nonspecific interstitial pneumonia (NSIP) pattern (CTD-NSIP) and cases of NSIP with an unknown etiology (NSIP-UE), as determined through multidisciplinary discussion. Nineteen patients with CTD-NSIP and 26 patients with NSIP-UE were included in the study for clinicopathological analysis. The CTD-NSIP group had a significantly higher proportion of female patients compared to the NSIP-UE group (79% vs. 31%; p = 0.002). The presence of both fresh and old intraluminal fibrosis within the same TBLC specimen was significantly more frequent in CTD-NSIP group than in the NSIP-UE group (p = 0.023). The presence of an NSIP pattern with co-existing fresh and old intraluminal fibrosis in TBLC specimens raised suspicion for CTD-ILD.

Diagnosis of interstitial lung disease (ILD) secondary to systemic sclerosis (SSc) and rheumatoid arthritis (RA) and identification of 'progressive pulmonary fibrosis' using chest CT: a narrative review

Interstitial lung disease (ILD) is a frequent manifestation of connective tissue diseases (CTDs), with incidence and prevalence variously assessed in the literature but reported in up to 30% of patients, with higher frequency in rheumatoid arthritis (RA) and systemic sclerosis (SSc). Recent years have seen a growing interest in the pulmonary manifestations of ILD-CTDs, mainly due to the widening of the use of anti-fibrotic drugs initially introduced exclusively for IPF, and radiologists play a key role because the lung biopsy is very rarely used in these patients where the morphological assessment is essentially left to imaging and especially HRCT. In this narrative review we will discuss, from the radiologist's point of view, the most recent findings in the field of ILD secondary to SSc and RA, with a special focus about the progression of disease and in particular about the 'progressive pulmonary fibrosis' (PPF) phenotype, and we will try to address two main issues: How to predict a possible evolution and therefore a worse prognosis when diagnosing a new case of ILD-CTDs and how to assess the progression of an already diagnosed ILD-CTDs.

The Evolving Concept of the Multidisciplinary Approach in the Diagnosis and Management of Interstitial Lung Diseases

BACKGROUND

Interstitial lung diseases (ILDs) are a group of heterogeneous diseases characterized by inflammation and/or fibrosis of the lung interstitium, leading to a wide range of clinical manifestations and outcomes. Over the years, the literature has demonstrated the increased diagnostic accuracy and confidence associated with a multidisciplinary approach (MDA) in assessing diseases involving lung parenchyma. This approach was recently emphasized by the latest guidelines from the American Thoracic Society, European Respiratory Society, Japanese Respiratory Society, and Latin American Thoracic Association for the diagnosis of ILDs.

METHODS

In this review, we will discuss the role, composition, and timing of multidisciplinary diagnosis (MDD) concerning idiopathic pulmonary fibrosis, connective tissue disease associated with ILDs, hypersensitive pneumonia, and idiopathic pneumonia with autoimmune features, based on the latest recommendations for their diagnosis.

RESULTS

The integration of clinical, radiological, histopathological, and, often, serological data is crucial in the early identification and management of ILDs, improving patient outcomes. Based on the recent endorsement of transbronchial cryo-biopsy in idiopathic pulmonary fibrosis guidelines, an MDA helps guide the choice of the sampling technique, obtaining the maximum diagnostic performance, and avoiding the execution of more invasive procedures such as a surgical lung biopsy. A multidisciplinary team should include pulmonologists, radiologists, pathologists, and, often, rheumatologists, being assembled regularly to achieve a consensus diagnosis and to review cases in light of new features.

CONCLUSIONS

The literature highlighted that an MDA is essential to improve the accuracy and reliability of ILD diagnosis, allowing for the early optimization of therapy and reducing the need for invasive procedures. The multidisciplinary diagnosis of ILDs is an ongoing and dynamic process, often referred to as a "working diagnosis", involving the progressive integration and re-evaluation of clinical, radiological, and histological features.

Transient Receptor Potential Vanilloid (TRPV4) channel inhibition: A novel promising approach for the treatment of lung diseases

Research on transient receptor potential vanilloid-4 (TRPV4) can provide a promising potential therapeutic target in the development of novel medicines for lung disorders. TRPV4 expresses in lung tissue and plays an important role in the maintenance of respiratory homeostatic function. TRPV4 is upregulated in life-threatening respiratory diseases like pulmonary hypertension, asthma, cystic fibrosis, and chronic obstructive pulmonary diseases. TRPV4 is linked to several proteins that have physiological functions and are sensitive to a wide variety of stimuli, such as mechanical stimulation, changes in temperature, and hypotonicity, and responds to a variety of proteins and lipid mediators, including anandamide (AA), the arachidonic acid metabolite, 5,6-epoxyeicosatrienoic acid (5,6-EET), a plant dimeric diterpenoid called bisandrographolide A (BAA), and the phorbol ester 4-alpha-phorbol-12,13-didecanoate (4α-PDD). This study focused on relevant research evidence of TRPV4 in lung disorders and its agonist and antagonist effects. TRPV4 can be a possible target of discovered molecules that exerts high therapeutic potential in the treatment of respiratory diseases by inhibiting TRPV4.

Diagnosis and Pharmacologic Management of Fibrotic Interstitial Lung Disease

Interstitial lung disease is an umbrella term that encompasses a spectrum of parenchymal lung pathologies affecting the gas exchanging part of the lung. While many of these disease entities are not fibrotic in nature, a number can lead to pulmonary fibrosis which may or may not progress over time. Idiopathic pulmonary fibrosis is the prototypical, progressive fibrotic interstitial lung disease, which can lead to worsening hypoxemic respiratory failure and mortality within a number of years from the time of diagnosis. The importance of an accurate and timely diagnosis of interstitial lung diseases, which is needed to inform prognosis and guide clinical management, cannot be overemphasized. Developing a consensus diagnosis requires the incorporation of a variety of factors by a multidisciplinary team, which then may or may not determine a need for tissue sampling. Clinical management can be challenging given the heterogeneity of disease behavior and the paucity of controlled trials to guide decision making. This review addresses current paradigms and recent updates in the diagnosis and pharmacologic management of these fibrotic interstitial lung diseases.

A Precise Method to Detect Post-COVID-19 Pulmonary Fibrosis Through Extreme Gradient Boosting

The association of pulmonary fibrosis with COVID-19 patients has now been adequately acknowledged and caused a significant number of mortalities around the world. As automatic disease detection has now become a crucial assistant to clinicians to obtain fast and precise results, this study proposes an architecture based on an ensemble machine learning approach to detect COVID-19-associated pulmonary fibrosis. The paper discusses Extreme Gradient Boosting (XGBoost) and its tuned hyper-parameters to optimize the performance for the prediction of severe COVID-19 patients who developed pulmonary fibrosis after 90 days of hospital discharge. A dataset comprising Electronic Health Record (EHR) and corresponding High-resolution computed tomography (HRCT) images of chest of 1175 COVID-19 patients has been considered, which involves 725 pulmonary fibrosis cases and 450 normal lung cases. The experimental results achieved an accuracy of 98%, precision of 99% and sensitivity of 99%. The proposed model is the first in literature to help clinicians in keeping a record of severe COVID-19 cases for analyzing the risk of pulmonary fibrosis through EHRs and HRCT scans, leading to less chance of life-threatening conditions.

[Latest news on RA-ILD]

Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is of high clinical relevance. It not only affects the quality of life but also makes a significant contribution to the mortality rate of patients with rheumatoid arthritis. RA-ILD can present with all known radiological and histopathological patterns seen in other interstitial pneumonias. Among these pneumonias, diffuse alveolar damage (DAD), followed by usual interstitial pneumonia (UIP) has the worst prognosis. In addition, acute exacerbation of RA-ILD, which can occur at any time during the disease, is highly lethal. An algorithm for the diagnosis and treatment of RA-ILD is pending and will be addressed in the following article. In addition to immunosuppressants and disease-modifying antirheumatic drugs (DMARD), antifibrotics have recently gained importance in the therapy of RA-ILD.

Syndrome of Combined Pulmonary Fibrosis and Emphysema: An Official ATS/ERS/JRS/ALAT Research Statement

Background: The presence of emphysema is relatively common in patients with fibrotic interstitial lung disease. This has been designated combined pulmonary fibrosis and emphysema (CPFE). The lack of consensus over definitions and diagnostic criteria has limited CPFE research. Goals: The objectives of this task force were to review the terminology, definition, characteristics, pathophysiology, and research priorities of CPFE and to explore whether CPFE is a syndrome. Methods: This research statement was developed by a committee including 19 pulmonologists, 5 radiologists, 3 pathologists, 2 methodologists, and 2 patient representatives. The final document was supported by a focused systematic review that identified and summarized all recent publications related to CPFE. Results: This task force identified that patients with CPFE are predominantly male, with a history of smoking, severe dyspnea, relatively preserved airflow rates and lung volumes on spirometry, severely impaired DlCO, exertional hypoxemia, frequent pulmonary hypertension, and a dismal prognosis. The committee proposes to identify CPFE as a syndrome, given the clustering of pulmonary fibrosis and emphysema, shared pathogenetic pathways, unique considerations related to disease progression, increased risk of complications (pulmonary hypertension, lung cancer, and/or mortality), and implications for clinical trial design. There are varying features of interstitial lung disease and emphysema in CPFE. The committee offers a research definition and classification criteria and proposes that studies on CPFE include a comprehensive description of radiologic and, when available, pathological patterns, including some recently described patterns such as smoking-related interstitial fibrosis. Conclusions: This statement delineates the syndrome of CPFE and highlights research priorities.

Clinical relevance of circulating autoantibodies in idiopathic pulmonary fibrosis; A NAt hard to break

Patients with idiopathic pulmonary fibrosis are screened for circulating autoantibodies as part of the initial interstitial lung disease workup. Management of seropositive idiopathic pulmonary fibrosis is currently considered no different than that of lone idiopathic pulmonary fibrosis. Emerging data however suggest that the former may possess distinct characteristics in terms of pathophysiology, histopathology, prognosis and amenability to immunomodulation. In that context, the aim of our study was to evaluate the influence of autoantibody status on: (i) the decline of forced vital capacity; (ii) the decline of diffusing capacity of lung for carbon monoxide; and (iii) 3-year survival; in a cohort of 102 idiopathic pulmonary fibrosis patients. In a pilot sub-study, we also sought to evaluate whether changes in antibody status during disease course affect the aforementioned parameters by potentially reflecting activity of the autoimmunity component of the pro-fibrotic mechanism.

Variables Associated With Response to Therapy in Patients With Interstitial Pneumonia With Autoimmune Features

BACKGROUND/OBJECTIVE

We have limited knowledge regarding characteristics of patients with interstitial pneumonia with autoimmune features (IPAF) that are associated with response to immunosuppression. In this study, we used published IPAF criteria to characterize features associated with response to treatment.

METHODS

We conducted a single-center medical records review study of 63 IPAF patients to evaluate for serological, clinical, and morphological characteristics that are associated with response to immunosuppression. Response was defined as % relative functional vital capacity decline of less than 10% and absence of death or lung transplant within the first year of continuous immunosuppressive therapy. Nonparametric measures of association and multivariate logistic regression were used to evaluate the relationship between baseline characteristics and immunosuppressive response.

RESULTS

There was a trend of greater progression among men, ever smokers, those negative for antisynthetase antibodies, and those with usual interstitial pneumonia radiographic pattern, but no statistically significant relationship was found between baseline serological, clinical, or morphological features and response to immunosuppression. Patients on combination therapy with mycophenolate mofetil and prednisone had less disease progression (p = 0.018) than those on regimens that did not include both of these medications.

CONCLUSIONS

In our cohort, baseline clinical assessment did not identify which patients with IPAF will respond to immunosuppressive therapy. Combination therapy with mycophenolate mofetil and prednisone was associated with lack of disease progression in our IPAF patients, including in IPAF-usual interstitial pneumonia. Further studies are needed to evaluate which IPAF patients would benefit from immunosuppressive therapy, antifibrotic therapy, or a combination of both.

2020 guide for the diagnosis and treatment of interstitial lung disease associated with connective tissue disease

The prognosis of patients with connective tissue disease (CTD) has improved significantly in recent years, but interstitial lung disease (ILD) associated with connective tissue disease (CTD-ILD) remains a refractory condition, which is a leading cause of mortality. Because it is an important prognostic factor, many observational and interventional studies have been conducted to date. However, CTD is a heterogeneous group of conditions, which makes the clinical course, treatment responses, and prognosis of CTD-ILD extremely diverse. To summarize the current understanding and unsolved questions, the Japanese Respiratory Society and the Japan College of Rheumatology collaborated to publish the world's first guide focusing on CTD-ILD, based on the evidence and expert consensus of pulmonologists and rheumatologists, along with radiologists, pathologists, and dermatologists. The task force members proposed a total of 27 items, including 7 for general topics, 9 for disease-specific topics, 3 for complications, 4 for pharmacologic treatments, and 4 for non-pharmacologic therapies, with teams of 2-4 authors and reviewers for each item to prepare a consensus statement based on a systematic literature review. Subsequently, public opinions were collected from members of both societies, and a critical review was conducted by external reviewers. Finally, the task force finalized the guide upon discussion and consensus generation. This guide is expected to contribute to the standardization of CTD-ILD medical care and is also useful as a tool for promoting future research by clarifying unresolved issues.

Recognition of Connective Tissue Disease-Related Interstitial Pneumonia Based on Histological Score-A Validation Study of an Online Diagnostic Decision Support Tool

Objectives: to evaluate the number of cases of idiopathic pulmonary fibrosis (IPF) that included histological features of connective tissue disease (CTD) and to check whether they demonstrated the clinical features of CTD, using a previously reported CTD-interstitial pneumonia (IP) index that histologically differentiates CTD-associated and idiopathic IP. Methods: patients diagnosed with IPF following video-assisted thoracoscopic biopsy through multidisciplinary team diagnosis between 2014 and 2017 were selected. Pathological observation was made by four pathologists who scored eight observational items needed for the CTD-IP index. Cases determined as CTD, by the CTD-IP index, were extracted, and their clinical features were compared. Results: a total of 94 cases of IPF were identified, of which 20 were classified into the CTD group using the CTD-IP index with reasonable interobserver agreement (k = 0.76). Cases pathologically classified into the CTD group were significantly associated with female sex, non-smoking history, autoantibody positivity, and CTD symptoms (p = 0.01, 0.03, 0.01, and 0.04, respectively). Conclusions: patients with IPF with pathological findings of CTD showed clinical characteristics similar to those of patients with CTD.

Interstitial Lung Disease in Connective Tissue Disease: A Common Lesion With Heterogeneous Mechanisms and Treatment Considerations

Connective tissue disease (CTD) related interstitial lung disease (CTD-ILD) is one of the leading causes of morbidity and mortality of CTD. Clinically, CTD-ILD is highly heterogenous and involves rheumatic immunity and multiple manifestations of respiratory complications affecting the airways, vessels, lung parenchyma, pleura, and respiratory muscles. The major pathological features of CTD are chronic inflammation of blood vessels and connective tissues, which can affect any organ leading to multi-system damage. The human lung is particularly vulnerable to such damage because anatomically it is abundant with collagen and blood vessels. The complex etiology of CTD-ILD includes genetic risks, epigenetic changes, and dysregulated immunity, which interact leading to disease under various ill-defined environmental triggers. CTD-ILD exhibits a broad spectra of clinical manifestations: from asymptomatic to severe dyspnea; from single-organ respiratory system involvement to multi-organ involvement. The disease course is also featured by remissions and relapses. It can range from stability or slow progression over several years to rapid deterioration. It can also present clinically as highly progressive from the initial onset of disease. Currently, the diagnosis of CTD-ILD is primarily based on distinct pathology subtype(s), imaging, as well as related CTD and autoantibodies profiles. Meticulous comprehensive clinical and laboratory assessment to improve the diagnostic process and management strategies are much needed. In this review, we focus on examining the pathogenesis of CTD-ILD with respect to genetics, environmental factors, and immunological factors. We also discuss the current state of knowledge and elaborate on the clinical characteristics of CTD-ILD, distinct pathohistological subtypes, imaging features, and related autoantibodies. Furthermore, we comment on the identification of high-risk patients and address how to stratify patients for precision medicine management approaches.

Interstitial Lung Disease Associated with Connective Tissue Diseases

Pulmonary manifestations of connective tissue diseases (CTD) carry high morbidity and potential mortality, and the most serious pulmonary type is interstitial lung disease (ILD). Identifying and promptly intervening CTD-ILD with immune suppressor therapy will change the natural course of the disease resulting in survival improvement. Compared to idiopathic pulmonary fibrosis, the most common presentation of idiopathic interstitial pneumonia (IIP), CTD-ILD carries a better prognosis due to the response to immune suppressor therapy. Nonspecific interstitial pneumonia (NSIP) is the most common type of CTD-ILD that is different from the fibrotic classical presentation of IPF, known as usual interstitial pneumonia (UIP). An exception is rheumatoid arthritis that presents more frequently with UIP type. Occasionally, IPF may not have typical radiographic features of UIP, and a full assessment to differentiate IPF from CTD-ILD is necessary, including the intervention of a multidisciplinary team and the histopathology. Interstitial pneumonia with autoimmune features (IPAF) shows promising advantages to identify patients with ILD who have some features of a CTD without a defined autoimmune disease and who may benefit from immune suppressors. A composition of clinical, serological, and morphologic features in patients presenting with ILD will fulfill criteria for IPAF. In summary, the early recognition and treatment of CTD-ILD, differentiation from IPF-UIP, and identification of patients with IPAF fulfill the assessment by the clinician for an optimal care.

Baseline Characteristics and Survival of an Australian Interstitial Pneumonia with Autoimmune Features Cohort

BACKGROUND AND OBJECTIVE

The research term "interstitial pneumonia with autoimmune features" (IPAF) encompasses interstitial lung disease (ILD) patients with autoimmune features not meeting diagnostic criteria for a defined connective tissue disease (CTD). It remains unclear if IPAF is a distinct disease entity with implications for management and prognosis. We describe an Australian IPAF population and compare their baseline characteristics and outcomes with distinct cohorts of idiopathic interstitial pneumonia (IIP), CTD-ILD, and unclassifiable ILD.

METHODS

Review of 291 consecutive patients attending a specialist ILD clinic was performed. Patients with a diagnosis of IIP, CTD-ILD, and unclassifiable ILD by ILD-multidisciplinary meeting (ILD-MDM) were included. Patients meeting the IPAF criteria were identified. Baseline clinical data, survival, and progression were compared between ILD groups.

RESULTS

226 patients were included, 36 meeting the IPAF criteria. IPAF patients demonstrated a high prevalence of autoantibodies to tRNA synthetase (35.3%), Ro52 (27.8%), and neutrophilic cytoplasmic antigens (ANCA; 20.0%). IPAF and CTD-ILD patients demonstrated similar clinical characteristics (mean age 66.6 and 63.7 years, respectively, female predominant, frequent CTD-manifestations). Lung function did not differ between ILD groups. Disease severity, pulmonary hypertension (PH), and ILD-MDM diagnosis were strong predictors of worse transplant-free survival (TFS). Meeting the IPAF criteria was not associated with TFS.

CONCLUSIONS

We identified IPAF as a heterogeneous phenotype that overlaps considerably with CTD-ILD. Disease severity, PH, and ILD-MDM diagnosis were more powerful predictors of survival outcomes than meeting the IPAF criteria.

Molecular markers of telomere dysfunction and senescence are common findings in the usual interstitial pneumonia pattern of lung fibrosis

AIMS

Idiopathic pulmonary fibrosis (IPF) is a genetically mediated, age-associated, progressive form of pulmonary fibrosis characterised pathologically by a usual interstitial pneumonia (UIP) pattern of fibrosis. The UIP pattern is also found in pulmonary fibrosis attributable to clinical diagnoses other than IPF (non-IPF UIP), whose clinical course is similarly poor, suggesting common molecular drivers. This study investigates whether IPF and non-IPF UIP lungs similarly express markers of telomere dysfunction and senescence.

METHODS AND RESULTS

To test whether patients with IPF and non-IPF UIP share molecular drivers, lung tissues from 169 IPF patients and 57 non-IPF UIP patients were histopathologically and molecularly compared. Histopathological changes in both IPF and non-IPF UIP patients included temporal heterogeneity, microscopic honeycombing, fibroblast foci, and dense collagen fibrosis. Non-IPF UIP lungs were more likely to have lymphocytic infiltration, non-caseating granulomas, airway-centred inflammation, or small airways disease. Telomeres were shorter in alveolar type II (AECII) cells of both IPF and non-IPF UIP lungs than in those of age-similar, unused donor, controls. Levels of molecular markers of senescence (p16 and p21) were elevated in lysates of IPF and non-IPF UIP lungs. Immunostaining localised expression of these proteins to AECII cells. The mucin 5B (MUC5B) gene promoter variant minor allele frequency was similar between IPF and non-IPF UIP patients, and MUC5B expression was similar in IPF and non-IPF UIP lungs.

CONCLUSIONS

Molecular markers of telomere dysfunction and senescence are pathologically expressed in both IPF and non-IPF UIP lungs. These findings suggest that common molecular drivers may contribute to the pathogenesis of UIP-associated pulmonary fibrosis, regardless of the clinical diagnosis.

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.

Senescence and autophagy in usual interstitial pneumonia of different etiology

Idiopathic pulmonary fibrosis (IPF) is a disease with a dismal prognosis. Currently, the causing agent(s) are poorly understood. Recent data suggest that senescence and autophagy might play a role in its development, as well as changes in metabolism due to hypoxic conditions. In this study, the expression of senescence markers in 23 cases of usual interstitial pneumonia (UIP)/IPF and UIP/chronic autoimmune diseases (UIP/AuD) was investigated. The status of autophagy was evaluated with respect to either antiinflammatory or antihypoxia function. Formalin-fixed paraffin-embedded tissues of UIP were selected for immunohistochemistry with antibodies for p21, p16, and β-galactosidase (senescence); for LC3, SIRT1, MAP1S, and pAMKα (autophagy); and for LDH and GLUT1 (metabolism). Epithelial cells in cystic remodeled areas of UIP stained for p16 and p21, p16 being more specific compared with p21. Myofibroblasts were negative in all cases. An upregulation of all four autophagy markers was seen not only in epithelia within remodeled areas and proliferating myofibroblasts, but also in bronchial epithelia and pneumocytes. Upregulated autophagy points to a compensatory mechanism for hypoxia; therefore, LDH and GLUT1 were investigated. Their expression was present in epithelia within cystic remodeling and in myofibroblasts. The cells within the remodeled areas stained for cytokeratin 5, but coexpressed TTF1, confirming their origin from basal cells of bronchioles. Within this population, senescent cells arise. Our results indicated that autophagy in UIP very likely helps cells to survive in hypoxic condition. By phagocytosis of cellular debris, they supplement their need for nutrition, and by upregulating LDH and GLUT1, they compensate for local hypoxia.

LncRNA SNHG16 promotes pulmonary fibrosis by targeting miR-455-3p to regulate the Notch2 pathway

Background

Idiopathic pulmonary fibrosis (IPF) is the most common interstitial lung diseases with a poor prognosis. Long non-coding RNAs (lncRNAs) have been reported to be involved in IPF in several studies. However, the role of lncRNA SNHG16 in IPF is largely unknown.

Methods

Firstly, experimental pulmonary fibrosis model was established by using bleomycin (BML). Histology and Western blotting assays were used to determine the different stages of fibrosis and expression of several fibrosis biomarkers. The expression of SNHG16 was detected by quantitative real-time polymerase chain reaction (qRT‐PCR). EdU staining and wound-healing assay were utilized to analyze proliferation and migration of lung fibroblast cells. Molecular mechanism of SNHG16 was explored by bioinformatics, dual-luciferase reporter assay, RNA immunoprecipitation assay (RIP), and qRT-PCR.

Results

The expression of SNHG16 was significantly up-regulated in bleomycin-(BLM) induced lung fibrosis and transforming growth factor-β (TGF-β)-induced fibroblast. Knockdown of SNHG16 could attenuate fibrogenesis. Mechanistically, SNHG16 was able to bind and regulate the expression of miR-455-3p. Moreover, SNHG16 also regulated the expression of Notch2 by targeting miR-455-3p. Finally, SNHG16 could promote fibrogenesis by regulating the expression of Notch2.

Conclusion

Taken together, our study demonstrated that SNHG16 promoted pulmonary fibrosis by targeting miR-455-3p to regulate the Notch2 pathway. These findings might provide a novel insight into pathologic process of lung fibrosis and may provide prevention strategies in the future.

Histopathologic Assessment of Suspected Idiopathic Pulmonary Fibrosis: Where We Are and Where We Need to Go

CONTEXT.—

Accurate diagnosis of idiopathic pulmonary fibrosis (IPF) requires multidisciplinary diagnosis that includes clinical, radiologic, and often pathologic assessment. In 2018, the American Thoracic Society, European Respiratory Society, Japanese Respiratory Society, and the Latin American Thoracic Society (ATS/ERS/JRS/ALAT) and the Fleischner Society each published guidelines for the diagnosis of IPF, which include criteria for 4 categories of confidence of a histologic usual interstitial pneumonia (UIP) pattern.

OBJECTIVE.—

To (1) identify the role of the guidelines in pathologic assessment of UIP; (2) analyze the 4 guideline categories, including potential areas of difficulty; and (3) determine steps the Pulmonary Pathology Society and the greater pulmonary pathology community can take to improve current guideline criteria and histopathologic diagnosis of interstitial lung disease.

DATA SOURCES.—

Data were derived from the guidelines, published literature, and clinical experience.

CONCLUSIONS.—

Both guidelines provide pathologists with a tool to relay to the clinician the likelihood that a biopsy represents UIP, and serve as an adjunct, not a replacement, for traditional histologic diagnosis. There are multiple challenges with implementing the guidelines, including (1) lack of clarity on the quantity and quality of histologic findings required, (2) lack of recognition that histologic features cannot be assessed independently, and (3) lack of guidance on how pathologists should incorporate clinical and radiographic information. Current criteria for "probable UIP" and "indeterminate for UIP" hinder accurate reflection of the likelihood of IPF. These challenges highlight the need for further morphologic-based investigations in the field of pulmonary pathology.

Histologic features suggesting connective tissue disease in idiopathic pulmonary fibrosis

Some patients with idiopathic pulmonary fibrosis (IPF) have histopathologic features suggesting connective tissue disease (CTD); however, their clinical course and prognosis remain unclear. Thus, we aimed to investigate the clinical course and prognosis of these patients with histologic autoimmune features. Among 114 patients with biopsy-proven IPF, the histologic features were semi-quantitatively graded, and CTD scores (range: 0-9) were calculated as the sum of each score of plasma cell infiltration, lymphoid aggregates, and germinal centres. Patients with high CTD scores (≥ 4) were classified into the interstitial pneumonia with histologic autoimmune features (IP-hAF) group. The mean age of the patients was 60.0 years; 74.6% were men, 69.3% were ever-smokers, and 35.1% had IP-hAF. During follow-up, the IP-hAF group showed slower decline in lung function, and better prognosis (median survival, 48.7 vs. 40.4 months; p = 0.015) than the no-IP-hAF group. On multivariate Cox analysis, IP-hAF was an independent prognostic factor (hazard ratio, 0.522; p = 0.016), along with the lower diffusing capacity for carbon monoxide, higher scores of reticulation and honeycombing, and usual interstitial pneumonia pattern on high-resolution computed tomography. Patients with IPF having histologic autoimmune features show distinct clinical characteristics and better outcome than those without histologic autoimmune features.

Predicting Survival Across Acute Exacerbation of Interstitial Lung Disease in Patients with Idiopathic Inflammatory Myositis: The GAP-ILD Model

INTRODUCTION

Risk prediction is challenging in patients with idiopathic inflammatory myopathies (IIM) and acute exacerbation of interstitial lung disease (AE-ILD) because of heterogeneity and patient-specific variables. Our objective was to assess whether mortality is accurately predicted in patients with IIM and AE-ILD by using the gender age physiology ILD (GAP-ILD) model, a clinical prediction model that was previously validated in patients with idiopathic pulmonary fibrosis.

METHODS

A retrospective cohort study was conducted in the First Affiliated Hospital, Zhejiang University, wherein 60 consecutive patients with IIM and AE-ILD admitted between February 2011 and April 2019. The GAP-ILD was assessed retrospectively on the basis of gender, age and pulmonary function test.

RESULTS

Patients with AE-ILD (n = 60) were identified and collected, 26 deaths occurred during follow-up, and the non-survivors group presented a higher level of GAP-ILD index (P = 0.005), bacterial infection (P = 0.013), and myositis disease activity assessment (MYOACT) (P = 0.031). The subsequent multivariate logistic regression analysis of overall mortality in AE-ILD revealed that bacterial infection (OR 5.275, P = 0.037) and GAP-ILD index (OR 2.292, P = 0.011) conferred significant risk of mortality. The GAP-ILD index was able to separate patients with AE-ILD into two groups with a statistically significant difference in survival rate (log rank P = 0.002). Satisfactory mortality estimation was maintained in the corresponding GAP-ILD index across the AE-ILD group.

CONCLUSION

The GAP-ILD model preforms well in risk prediction of mortality among patients with IIM and AE-ILD. Pulmonary bacterial infection can also be taken as an initial predictor of poor prognosis in patients with IIM and AE-ILD that must be taken seriously.

Etiology, Risk Factors, and Biomarkers in Systemic Sclerosis with Interstitial Lung Disease

Systemic sclerosis (SSc) is a complex, multiorgan, autoimmune disease. Lung fibrosis occurs in ∼80% of patients with SSc; 25% to 30% develop progressive interstitial lung disease (ILD). The pathogenesis of fibrosis in SSc-associated ILD (SSc-ILD) involves cellular injury, activation/differentiation of mesenchymal cells, and morphological/biological changes in epithelial/endothelial cells. Risk factors for progressive SSc-ILD include older age, male sex, degree of lung involvement on baseline high-resolution computed tomography imaging, reduced Dl_CO, and reduced FVC. SSc-ILD does not share the genetic risk architecture observed in idiopathic pulmonary fibrosis (IPF), with key risk factors yet to be identified. Presence of anti-Scl-70 antibodies and absence of anti-centromere antibodies indicate increased likelihood of progressive ILD. Elevated levels of serum Krebs von den Lungen-6 and C-reactive protein are both associated with SSc-ILD severity and predict SSc-ILD progression. A promising prognostic indicator is serum chemokine (C-C motif) ligand 18. SSc-ILD shares similarities with IPF, although clear differences exist. Histologically, a nonspecific interstitial pneumonia pattern is commonly observed in SSc-ILD, whereas IPF is defined by usual interstitial pneumonia. The course of SSc-ILD is variable, ranging from minor, stable disease to a progressive course, whereas all patients with IPF experience progression of disease. Although appropriately treated patients with SSc-ILD have better chances of stabilization and survival, a relentlessly progressive course, akin to IPF, is seen in a minority. Better understanding of cellular and molecular pathogenesis, genetic risk, and distinctive features of SSc-ILD and identification of robust prognostic biomarkers are needed for optimal disease management.

Pathology of Idiopathic Interstitial Pneumonias

This review discusses diagnostic pathology in idiopathic interstitial pneumonias (IIPs). Accurate understanding of basic structure of lung lobules is critical because the location of abnormalities inside the lobule is an important effector of pathology diagnosis. Depending on the method of obtaining tissue, recognition of the location may be difficult or impossible. Cryobiopsy is a new technology and its coverage of lung lobules is limited. This article discusses fundamental anatomy and approach to interstitial pneumonia. In addition, most histologic types of IIPs are covered, but the focus is on diagnosis of usual interstitial pneumonia because of its clinical importance.

Systematic review and meta-analysis of the prognosis and prognostic factors of interstitial pneumonia with autoimmune features

OBJECTIVE

To clarify the prognosis and prognostic factors of interstitial pneumonia with autoimmune features (IPAF) in comparison to idiopathic pulmonary fibrosis (IPF), the most common idiopathic interstitial pneumonia, and connective tissue disease-associated interstitial pneumonia (CTD-IP).

DESIGN

A systematic review and meta-analysis.

DATA SOURCES

Electronic databases such as Medline and Embase were searched from 2015 through 6 September 2019.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Primary studies that comparatively investigated the prognosis or prognostic factors of IPAF were eligible.

DATA EXTRACTION AND ANALYSIS

Two reviewers extracted relevant data and assessed the risk of bias independently. A meta-analysis was conducted using a random-effects model. The quality of presented evidence was assessed by the Grades of Recommendation, Assessment, Development, and Evaluation system.

RESULTS

Out of a total of 656 records retrieved, 12 studies were reviewed. The clinical features of IPAF were diverse between studies, which included a radiological and/or pathological usual interstitial pneumonia (UIP) pattern of between 0% and 73.8%. All studies contained some risk of bias. There was no significant difference of all-cause mortality between IPAF-UIP and IPF in all studies, although the prognosis of IPAF in contrast to IPF or CTD-IP varied between studies depending on the proportion of UIP pattern. Among the potential prognostic factors identified, age was significantly associated with all-cause mortality of IPAF by a pooled analysis of univariate results with a hazard ratio (HR) of 1.06 (95% confidence interval (CI) 1.04 to 1.07). The adjusted effect of age was also significant in all studies. The quality of presented evidence was deemed as very low.

CONCLUSION

There was no significant difference of all-cause mortality between IPAF-UIP and IPF. Age was deemed as a prognostic factor for all-cause mortality of IPAF. The findings should be interpreted cautiously due to the low quality of the presented evidence.

PROSPERO REGISTRATION NUMBER

CRD42018115870.

Acute exacerbations of fibrosing interstitial lung disease associated with connective tissue diseases: a population-based study

Background

Acute exacerbation (AE) is the major cause of morbidity and mortality in patients with idiopathic pulmonary fibrosis (IPF). AEs also occur in other forms of fibrosing interstitial lung disease (fILD). The clinical features and prognosis of AE patients with connective tissue diseases (CTDs) associated-ILD has not been fully described.

Methods

We retrospectively reviewed 177 patients with either IPF or a characterized CTD-ILD admitted to Nanjing Drum Tower Hospital with an AE from January 2010 to December 2016.

Results

The study cohort included 107 subjects with AE-IPF and 70 cases with AE-CTD-ILD. Female gender, prior use of corticosteroid and immunosupressants, lower serum albumin, higher D-dimer level, TLC% pred, survival, and treatment with immunosupressants and caspofungin were more common in the CTD-ILD group (all p<0.05). The incidences of AE-CTD-ILD and AE-IPF were similar in our single center (p = 0.526). TLC% pred was the risk factor for AE after ILD diagnosis for 1 year in CTD patients (p = 0.018). Log-rank tests showed patients with CTD-ILD had a significantly lower mortality rate compared with IPF patients after AEs (p = 0.029). No significant difference in survival was noted among CTD subgroups (p = 0.353). The survival was negatively correlated with WBC count, LDH and CT score, (p = 0.006, p = 0.013 and p = 0.035, respectively), and positively correlated with PaO₂/FiO₂ ratio (p<0.001) in the CTD-ILD group. WBC count and PO₂/FiO₂ ratio were the independent predictors for survival in AE-CTD-ILD after adjusting for other clinical variates in Cox regression Models (p = 0.038 and p < 0.001, respectively).

Conclusions

The clinical characteristics of patients with AE-CTD-ILD differed from those with AE-IPF, while AE incidences were similar between the two groups. Subjects with AE-CTD-fILD tended to have a better prognosis, and WBC count and PO₂/FiO₂ ratio were the independent survival predictors for these patients.

The Role of the Multidisciplinary Evaluation of Interstitial Lung Diseases: Systematic Literature Review of the Current Evidence and Future Perspectives

The opportunity of a multidisciplinary evaluation for the diagnosis of interstitial pneumonias highlighted a major change in the diagnostic approach to diffuse lung disease. The new American Thoracic Society, European Respiratory Society, Japanese Respiratory Society, and Latin American Thoracic Society guidelines for the diagnosis of idiopathic pulmonary fibrosis have reinforced this assumption and have underlined that the exclusion of connective tissue disease related lung involvement is mandatory, with obvious clinical and therapeutic impact. The multidisciplinary team discussion consists in a moment of interaction among the radiologist, pathologist and pulmonologist, also including the rheumatologist when considered necessary, to improve diagnostic agreement and optimize the definition of those cases in which pulmonary involvement may represent the first or prominent manifestation of an autoimmune systemic disease. Moreover, the proposal of classification criteria for interstitial lung disease with autoimmune features (IPAF) represents an effort to define lung involvement in clinically undefined autoimmune conditions. The complexity of autoimmune diseases, and in particular the lack of classification criteria defined for pathologies such as anti-synthetase syndrome, makes the involvement of the rheumatologist essential for the correct interpretation of the autoimmune element and for the application of classification criteria, that could replace clinical pictures initially interpreted as IPAF in defined autoimmune disease, minimizing the risk of misdiagnosis. The aim of this review was to evaluate the available evidence about the efficiency and efficacy of different multidisciplinary team approaches, in order to standardize the professional figures and the core set procedures that should be necessary for a correct approach in diagnosing patients with interstitial lung disease.

Systemic Sclerosis Associated Interstitial Lung Disease: New Directions in Disease Management

A subgroup of patients with systemic sclerosis (SSc) develop interstitial lung disease (ILD), characterized by inflammation and progressive scarring of the lungs that can lead to respiratory failure. Although ILD remains the major cause of death in these individuals, there is no consensus statement regarding the classification and characterization of SSc-related ILD (SSc-ILD). Recent clinical trials address the treatment of SSc-ILD and the results may lead to new disease-altering therapies. In this review, we provide an update to the diagnosis, management and treatment of SSc-ILD.

Interstitial Pneumonia With Autoimmune Features (IPAF)

A significant proportion of patients with interstitial lung disease (ILD) manifest autoimmune features, but do not fulfill the diagnostic criteria for a definite connective tissue disease (CTD). In 2015, the European Respiratory Society (ERS) and American Thoracic Society (ATS) “Task Force on undifferentiated Forms of connective tissue disease-associated interstitial lung disease” proposed classification criteria for a so-called research category of Interstitial Pneumonia with Autoimmune Features (IPAF). These classification criteria were based on a combination of features from three domains: a clinical domain consisting of extra-thoracic features; a serologic domain with specific autoantibodies; and a morphologic domain with imaging patterns, histopathological findings or multi-compartment involvement. Patients meeting IPAF criteria tend to have a history of smoking similar to patients with idiopathic pulmonary fibrosis. The most frequent clinical and serological markers of autoimmune features are Raynaud' phenomenon and positive antinuclear antibodies, respectively. Non-specific interstitial pneumonia is the predominant radiologic and histopathologic pattern, although patients meeting IPAF criteria through the clinical and serologic domains may also have a usual interstitial pneumonia pattern. Management should be carefully individualized on a case-by-case basis in keeping with the wide heterogeneity of IPAF and lack of evidence in this particular subgroup of patients. Prognosis is generally intermediate between that of idiopathic pulmonary fibrosis and connective tissue disease-associated interstitial lung disease, but substantially variable according to the predominant histologic and radiologic patterns. As acknowledged by the Task Force, the proposed classification scheme of IPAF is a research concept that will need revision and refinement based on data to better inform prognostication and patient care.

Long-term clinical course and outcome of interstitial pneumonia with autoimmune features

BACKGROUND AND OBJECTIVE

Idiopathic interstitial pneumonia (IIP) with autoimmune features that does not fulfil connective tissue disease (CTD) criteria has been recently defined as interstitial pneumonia with autoimmune features (IPAF). However, its long-term clinical course and outcome are poorly understood.

METHODS

We included consecutive patients diagnosed with IIP (n = 586) or CTD-related interstitial lung disease (CTD-ILD, n = 149). Some patients with IIP were reclassified as IPAF based on recent guidelines.

RESULTS

The median follow-up period was 45 months. Among the IIP patients, 109 (18.6%) were reclassified as IPAF. Compared to the non-IPAF-IIP group, the IPAF group had slower diffusing capacity of the lung for carbon monoxide (DL_CO ) and total lung capacity declines, and more frequent CTD development during follow-up periods. The prognosis of the IPAF was better than that of the non-IPAF-IIP and similar to that of the CTD-ILD. IPAF was associated with better prognosis in the IIP cohort on univariate but not on multivariate analysis. Usual interstitial pneumonia (UIP) pattern, old age and low DL_CO independently predicted mortality in the IPAF group.

CONCLUSION

Compared to the non-IPAF-IIP group, the IPAF group had slower lung function declines and more frequent CTD development during follow-up. Although the prognosis of IPAF group was better than that of non-IPAF-IIP group and similar to that of CTD-ILD group, it showed poor prognosis in patients with old age, UIP pattern, and low DL_CO .

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.

Lung Cancer development and mortality in interstitial lung disease with and without connective tissue diseases: a five-year Nationwide population-based study

Background

Connective tissue disease associated with interstitial lung disease (CTD-ILD) and interstitial lung disease (ILD) alone have same pathological and imaging backgrounds. However, the differences between lung cancer development and the mortality risk between these two conditions are unclear. Incidence of primary lung cancer and all-cause mortality were studied between interstitial lung disease patients with and without connective tissue disease.

Methods

Data were extracted from the Korean National Health Insurance Research Database in 2009. A total of 12,787 cases of ILD without idiopathic pulmonary fibrosis and 2491 cases of CTD-ILD were diagnosed in 2009. The cohort was followed up until June 30, 2014. Incident lung cancers and all-cause mortality were ascertained.

Results

The overall incidence of lung cancer was 165.7 and 161.8 per 10,000 person-years in the CTD-ILD and ILD-only, respectively (rate ratio, 1.08; 95% confidence interval, 0.89–1.30). CTD-ILD patients in the 40–49 and 50–59 years old age groups had lung cancer incidence rates of 92.5 and 139.2, which were 2.0 and 1.7 times higher than those in the ILD-only, respectively. All-cause mortality was significantly higher in the CTD-ILD group compared to ILD-only group in patients aged 50–79 years. All-cause mortality of women in the 50–59, 60–69 and 70–79 age groups was 2.0, 1.8, and 1.4 times higher in the CTD-ILD group than in the ILD-only group, respectively.

Conclusions

CTD-ILD patients aged < 60 years had a higher lung cancer incidence than ILD-only patients in the same age group. Furthermore, CTD-ILD patients aged 50–79 years had higher all-cause mortality than ILD-only patients in the same age group.

Korean Guidelines for Diagnosis and Management of Interstitial Lung Diseases: Part 5. Connective Tissue Disease Associated Interstitial Lung Disease

Connective tissue disease (CTD) is a collection of disorders characterized by various signs and symptoms such as circulation of autoantibodies in the entire system causing damage to internal organs. Interstitial lung disease (ILD) which is associated with CTD is referred to as CTD-ILD. Patients diagnosed with ILD should be thoroughly examined for the co-occurrence of CTD, since the treatment procedures and prognosis of CTD-ILD are vary from those of idiopathic interstitial pneumonia. The representative types of CTD which may accompany ILD include rheumatoid arthritis, systemic sclerosis (SSc), Sjögren's syndrome, mixed CTD, idiopathic inflammatory myopathies, and systemic lupus erythematous. Of these, ILD most frequently co-exists with SSc. If an ILD is observed in the chest, high resolution computed tomography and specific diagnostic criteria for any type of CTD are met, then a diagnosis of CTD-ILD is made. It is challenging to conduct a properly designed randomized study on CTD-ILD, due to low incidence. Therefore, CTD-ILD treatment approach is yet to been established in absence of randomized controlled clinical trials, with the exception of SSc-ILD. When a patient is presented with acute CTD-ILD or if symptoms occur due to progression of the disease, steroid and immunosuppressive therapy are generally considered.

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.

Autoantibody status is not associated with change in lung function or survival in patients with idiopathic pulmonary fibrosis

INTRODUCTION

A proportion of patients with idiopathic pulmonary fibrosis (IPF) have autoantibodies directed against intracellular targets. This study aimed to determine the relationship between serologic status, lung function decline and survival.

METHODS

IPF patients assessed for antinuclear antibody (ANA) and related antigen-specific serology detected by addressable laser bead immunoassay (ALBIA) were included. Demographics, serial pulmonary function tests and survival were compared between patients with and without autoantibodies. Linear mixed models were used to estimate changes in forced vital capacity (FVC) and diffusion capacity for carbon monoxide (DLCO) over time. Cox-proportional hazards models were used to compare survival, adjusted for a composite score including age, sex and baseline lung function.

RESULTS

Of 61 included patients, the mean baseline age was 70 years (SD = 9), 77% were male, and 87% were Caucasian. Either ANA or antigen-specific serology by ALBIA was positive in 25 (41%) during follow-up. ANA was detected in 23 (38%), and specific autoantibodies by ALBIA in 6 (10%). There was no difference in age, sex, race, smoking status, anti-fibrotic use or baseline FVC or DLCO in patients with and without autoantibodies. There was no association between autoantibody status and survival (HR = 1.18, 95% CI 0.61, 2.29), rate of decline in FVC or DLCO (difference in FVC = 4.2 mL/year, p = 0.82; difference in DLCO = 4.6*10^-4mL/min/mmHg/year, p = 0.20).

CONCLUSION

These data suggest that autoantibodies are common in IPF and that patients with a subset of autoantibodies, but without features of autoimmunity, demonstrate similar disease behaviour to those without autoantibodies.

Unclassifiable interstitial lung disease: from phenotyping to possible treatments

PURPOSE OF REVIEW

Accurate diagnosis of interstitial lung diseases (ILDs) can be challenging, and a substantial percentage of ILD patients remain unclassifiable even after thorough assessment by an experienced multidisciplinary team. In this review, we summarize the recent literature on the definition, prevalence, diagnosis, treatment, and prognosis of unclassifiable ILD, and also discuss important current issues and provide future perspectives on the classification of ILD.

RECENT FINDINGS

Approximately 12% of patients with ILD are considered unclassifiable, with large variability across previous studies that is in part secondary to inconsistent definitions of unclassifiable ILD and other ILD subtypes. A recent International Working Group suggested that unclassifiable ILD should be defined by the absence of a leading diagnosis that is considered more likely than not after multidisciplinary discussion of all available information. Clinical features and outcomes of unclassifiable ILD are intermediate between idiopathic pulmonary fibrosis and nonidiopathic pulmonary fibrosis ILD cohorts, and choices for pharmacotherapy should be considered on a case-by-case basis.

SUMMARY

Recent studies have provided additional data on the clinical features and prognosis of unclassifiable ILD, but also highlight the many uncertainties that still exist in ILD diagnosis and classification. New tools are needed to more accurately characterize patients with unclassifiable ILD.

Comparison of clinical courses and mortality of connective tissue disease-associated interstitial pneumonias and chronic fibrosing idiopathic interstitial pneumonias

Interstitial lung disease (ILD) is a common pulmonary manifestation of connective tissue diseases (CTD). Prognostic effect of radiological usual interstitial pneumonia (UIP) pattern in CTD-associated interstitial lung disease (CTD-ILD) is unknown. This study aimed to investigate the disease progression and mortality of patients with CTD-ILD and idiopathic interstitial pneumonias (IIP) including idiopathic pulmonary fibrosis (IPF) and idiopathic nonspecific interstitial pneumonia and the prognostic impact of the radiological UIP pattern on both disease groups. The medical records of 91 patients (55 with CTD-ILD and 36 with IIP) diagnosed with ILD at pulmonary medicine department, Faculty of Medicine, Gazi University from 2004 to 2014 were retrospectively reviewed. Patients included whose baseline high-resolution computed tomography (HRCT) scans showed either a UIP or non-UIP pattern. While 67.3% (n = 37) of CTD-ILD patients possessed UIP pattern, 38.9% (n = 14) of IIP patients had UIP pattern in HRCT. Respiratory functions including the forced expiratory volume in the first second (FEV₁ ), functional vital capacity (FVC), and transfer coefficient for carbon monoxide (diffusing capacity of the lung for carbon monoxide [DLCO]) of IIP group at the time of diagnosis were significantly lower than CTD-ILD group (P = .007, P = .002, and P = .019, respectively). There was no significant survival difference between CTD-ILD and IIP by using the log-rank test (P = .76). Multivariate analysis revealed that UIP pattern in HRCT (Hazard ratio: 1.85; 95% Confidence interval = 1.14-3; P = .013), annual FVC (Hazard ratio: 0.521; 95% Confidence interval = 0.32-0.84; P = .007), and annual DLCO declines (Hazard ratio: 0.943; 95% Confidence interval = 0.897-0.991; P = .02) were independent risk factors for mortality in both CTD-ILD and IIP groups. We found that UIP pattern in HRCT and annual losses in respiratory functions were the main determinants of prognosis of ILDs either idiopathic or CTD-associated.

Radiological patterns of pulmonary involvement may predict treatment response in rheumatoid arthritis: A retrospective study

BACKGROUND

There have been no reports on the relationship between lung radiological patterns and rheumatoid arthritis (RA) disease activity or RA treatment response in patients with RA-associated lung disease (RA-LD).

METHODS

Patients with RA-LD who underwent treatment for RA from April 2005 to March 2015 were retrospectively evaluated. RA-LD patients were divided into three groups based on high-resolution computed tomography (HRCT) patterns [usual interstitial pneumonia (UIP), nonspecific interstitial pneumonia (NSIP), and bronchiolitis]. The disease activity score of 28 joints-erythrocyte sedimentation rate (DAS28-ESR) and the response of RA to treatment, as measured by the European League Against Rheumatism (EULAR) response criteria, were investigated.

RESULTS

A total of 77 patients (21 with UIP, 23 with NSIP, and 33 with bronchiolitis) were enrolled. Median scores (interquartile range) on the DAS28-ESR at baseline were 5.27 (4.76-5.74), 5.48 (4.24-6.34), and 5.04 (3.90-5.66) for UIP, NSIP, and bronchiolitis, respectively; there were no statistical differences between the three groups (p = 0.412). One year after baseline, 19 (90%), 14 (61%), and 19 (58%) of patients in the UIP, NSIP, and bronchiolitis groups, respectively, were considered good or moderate responders, as evaluated using the EULAR response criteria; there was a significant difference between these three groups (p = 0.014). Multiple logistic regression analysis revealed that the UIP pattern was significantly associated with good or moderate response to RA treatment 1 year after baseline (p = 0.012).

CONCLUSIONS

These results suggest that NSIP and bronchiolitis HRCT patterns may be risk factors for resistance to RA therapy.

Pathological interpretation of connective tissue disease-associated lung diseases

Connective tissue diseases (CTDs) can affect all compartments of the lungs, including airways, alveoli, interstitium, vessels, and pleura. CTD-associated lung diseases (CTD-LDs) may present as diffuse lung disease or as focal lesions, and there is significant heterogeneity between the individual CTDs in their clinical and pathological manifestations. CTD-LDs may presage the clinical diagnosis a primary CTD, or it may develop in the context of an established CTD diagnosis. CTD-LDs reveal acute, chronic or mixed pattern of lung and pleural manifestations. Histopathological findings of diverse morphological changes can be present in CTD-LDs airway lesions (chronic bronchitis/bronchiolitis, follicular bronchiolitis, etc.), interstitial lung diseases (nonspecific interstitial pneumonia/fibrosis, usual interstitial pneumonia, lymphocytic interstitial pneumonia, diffuse alveolar damage, and organizing pneumonia), pleural changes (acute fibrinous or chronic fibrous pleuritis), and vascular changes (vasculitis, capillaritis, pulmonary hemorrhage, etc.). CTD patients can be exposed to various infectious diseases when taking immunosuppressive drugs. Histopathological patterns of CTD-LDs are generally nonspecific, and other diseases that can cause similar lesions in the lungs must be considered before the diagnosis of CTD-LDs. A multidisciplinary team involving pathologists, clinicians, and radiologists can adequately make a proper diagnosis of CTD-LDs.

Proposed method of histological separation between connective tissue disease-associated interstitial pneumonia and idiopathic interstitial pneumonias

OBJECTIVES

Idiopathic interstitial pneumonia (IIP) and connective tissue disease -associated interstitial pneumonia (CTD-IP) are the two most common types of interstitial pneumonia. IIP and CTD-IP share common histological features, yet their clinical management is different. Separation of the two conditions based solely on histology can be challenging, and there are no established criteria.

MATERIALS AND METHODS

We selected 105 consecutive cases of IIP (79 usual interstitial pneumonia and 26 non-specific interstitial pneumonia) and 49 cases of CTD-IP for derivation and 32 cases of IIP and 10 cases of CTD-IP for validation. Fourteen histological parameters were evaluated independently by two pathologists for derivation group and graded into 0 to 3. The association between the score for each marker and a diagnosis of CTD was investigated using Fisher's exact test and stepwise logistic regression analysis. A formula for calculating the probability of IIP and CTD-IP was constructed by the markers identified in the regression test with coefficients for each finding. The formula was confirmed using validation case group.

RESULTS

Stepwise logistic regression analysis showed that plasmacytosis, lymphoid follicle with germinal center, and airspace fibrin were suggestive of CTD-IP and that fibroblastic foci, smooth muscle hyperplasia, cellular IP, dense perivascular collagen, and fat metaplasia were suggestive of IIP. The formula used to calculate the probabilities based on estimated values for each finding was created, and user-friendly web based app was composed at www.ctdip.com. On the validation study, 30 out of 32 IIP and eight out of 10 CTD-IPs were distinguished correctly by the app (Specificity: 93%, Sensitivity: 80%).

CONCLUSIONS

We identified histological markers and derived a practical formula and user-friendly app to distinguish CTD-IPs from IIP.

Diagnosis of Idiopathic Pulmonary Fibrosis: Differential Diagnosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, and fibrotic interstitial lung disease of unknown origin with a characteristic imaging and histologic pattern called usual interstitial pneumonia (UIP). The diagnosis of IPF is a complex procedure that requires the support of various specialists, who must integrate clinical, radiological, and histological data. The multidisciplinary team (MDT) has become the new gold standard to diagnose and manage the disease, increasing the accuracy and agreement of the diagnosis between different centers. It is mandatory to exclude nonspecific interstitial pneumonia or other diseases that can cause the UIP pattern, particularly drugs or exposure diseases, including chronic hypersensitivity pneumonitis or systemic autoimmune disease. The role of the MDT is also to decide who could need a biopsy or to review patient diagnoses at regular intervals in those with additional information or unexpected evolution. This review provides updated information to achieve a proper IPF diagnosis.

Morphologic Aspects of Interstitial Pneumonia With Autoimmune Features

Context.—

Interstitial lung disease, a common complication observed in several connective tissue diseases, causes significant morbidity and mortality. Similar to individuals with connective tissue diseases, a significant subgroup of patients with clinical and serologic characteristics suggestive of autoimmunity but without confirmed specific connective tissue disease presents with associated interstitial lung disease. These patients have been classified using different controversial nomenclatures, such as undifferentiated connective tissue disease–associated interstitial lung disease, lung-dominant connective tissue disease, and autoimmune featured interstitial lung disease. The need for a better understanding and standardization of this entity, interstitial lung disease with autoimmune features, and the need for an adequate management protocol for patients resulted in the introduction of a new terminology in 2015: interstitial pneumonia with autoimmune features. This new classification requires a better comprehension of its diagnostic impact and the influence of its morphologic aspects on the prognosis of patients.

Objective.—

To review the diagnostic criteria for interstitial pneumonia with autoimmune features, with an emphasis on morphologic aspects.

Data Sources.—

The review is based on the available literature, and on pathologic, radiologic, and clinical experience.

Conclusions.—

The interstitial pneumonia with autoimmune features classification seems to identify a distinct subgroup of patients with different prognoses. Studies show that nonspecific interstitial pneumonia and usual interstitial pneumonia are the most prevalent morphologic patterns and show discrepant results on the impact of the usual interstitial pneumonia pattern on survival. Prospective investigations are necessary to better define this subgroup and to determine the prognosis and appropriate clinical management of these patients.

[Pulmonary fibrosis in rheumatic diseases]

Rheumatic diseases are frequently complicated by secondary pulmonary diseases, which often impair the quality of life and increase the mortality of patients. A correct classification of such pulmonary complications is important to ensure appropriate treatment and optimal prognosis. The diagnostic and therapeutic challenge is to find the precise diagnosis and appropriate therapy among the multitude of potential causes for respiratory symptoms. It is important to maintain a cautious approach to invasive diagnostics, even though the differential diagnostics of infections or toxic lung disease might be crucial. The situation is further complicated by the frequent lack of evidence for therapies. Especially in the case of pulmonary fibrosis which is comparable to cancer in its complexity and high mortality, the diagnostics and therapy should be discussed in appropriate interdisciplinary boards.

Radiological images of interstitial pneumonia in mixed connective tissue disease compared with scleroderma and polymyositis/dermatomyositis

OBJECTIVE

Little has been reported on the radiological and pathological findings of interstitial pneumonia in mixed connective tissue disease (MCTD). There may be possible difference in treatment response and prognosis between the imaging patterns of systemic sclerosis (SSc)-like and polymyositis/dermatomyositis (PM/DM)-like. The purpose of this study was to examine whether the radiological images of interstitial pneumonia in MCTD presented SSc-like or PM/DM-like pattern, and to assess whether the imaging patterns corresponded to clinical and pathological features.

MATERIALS AND METHODS

This retrospective study included 29 patients with interstitial pneumonia who underwent surgical lung biopsy; 10 with SSc, 10 with PM/DM, and 9 with MCTD. High resolution computed tomography (HRCT) images were classified as SSc, PM/DM, or the other pattern by two radiologists independently without clinical information. The pathology of the lung specimens from MCTD patients were evaluated and compared with the imaging pattern.

RESULTS

The concordance rate between clinical diagnosis and radiological pattern was 100% in SSc patients, and 80% in PM/DM patients. Among patients with MCTD, imaging patterns were classified as SSc pattern in 4 (MCTD-SSc), PM/DM pattern in 4 (MCTD-PM/DM) and other in one. The imaging patterns did not always correlate with the clinical findings in MCTD patients. Pathologically, plasma cell infiltration and organizing pneumonia were relatively more frequent in MCTD-PM/DM, and smooth muscle hyperplasia was relatively more frequent in MCTD-SSc.

CONCLUSION

HRCT images in MCTD patients can be classified as SSc pattern or PM/DM pattern. MCTD-SSc and MCTD-PM/DM were corresponded to similar pathological findings of SSc and PM/DM.

S100A4+ Macrophages Are Necessary for Pulmonary Fibrosis by Activating Lung Fibroblasts

S100A4, a calcium-binding protein, can promote pulmonary fibrosis via fibroblast activation. Due partly to its various cellular origins, the exact role of S100A4 in the development of lung fibrosis remains elusive. Here, we show that in the bronchoalveolar lavage fluid, numbers of S100A4⁺ macrophages correlated well with S100A4 protein levels and occurrence of idiopathic pulmonary fibrosis (IPF) in patients. A mouse model of bleomycin-induced pulmonary fibrosis demonstrated S100A4⁺ macrophages as main source for extracellular S100A4 in the inflammatory phase. In vitro studies revealed that extracellular S100A4 could activate both mouse and human lung fibroblasts by upregulation of α-SMA and type I collagen, during which sphingosine-1-phosphate (S1P) increased. Inhibiting the S1P receptor subtypes S1P₁/S1P₃ abrogated fibroblast activation. Accordingly, absence or neutralization of S100A4 significantly attenuated bleomycin-induced lung fibrosis in vivo. Importantly, adoptive transfer of S100A4⁺ but not of S100A4⁻ macrophages installed experimental lung injury in S100A4^−/− mice that were otherwise not sensitive to fibrosis induction. Taken together, S100A4 released by macrophages promotes pulmonary fibrosis through activation of lung fibroblasts which is associated with S1P. This suggests that extracellular S100A4 or S100A4⁺ macrophages within the lung as promising targets for early clinical diagnosis or therapy of IPF.