Prognostic implications of histologic patterns in multiple surgical lung biopsies from patients with idiopathic interstitial pneumonias

SOCS domain targets ECM assembly in lung fibroblasts and experimental lung fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal disease defined by a progressive decline in lung function due to scarring and accumulation of extracellular matrix (ECM) proteins. The SOCS (Suppressor Of Cytokine Signaling) domain is a 40 amino acid conserved domain known to form a functional ubiquitin ligase complex targeting the Von Hippel Lindau (VHL) protein for proteasomal degradation. Here we show that the SOCS conserved domain operates as a molecular tool, to disrupt collagen and fibronectin fibrils in the ECM associated with fibrotic lung myofibroblasts. Our results demonstrate that fibroblasts differentiated using TGFß, followed by transduction with the SOCS domain, exhibit significantly reduced levels of the contractile myofibroblast-marker, α-SMA. Furthermore, in support of its role to retard differentiation, we find that lung fibroblasts expressing the SOCS domain present with significantly reduced levels of α-SMA and fibrillar fibronectin after differentiation with TGFß. We show that adenoviral delivery of the SOCS domain in the fibrotic phase of experimental lung fibrosis in mice, significantly reduces collagen accumulation in disease lungs. These data underscore a novel function for the SOCS domain and its potential in ameliorating pathologic matrix deposition in lung fibroblasts and experimental lung fibrosis.

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.

Early Detection and Staging of Lung Fibrosis Enabled by Collagen-Targeted MRI Protein Contrast Agent

Chronic lung diseases, such as idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD), are major leading causes of death worldwide and are generally associated with poor prognoses. The heterogeneous distribution of collagen, mainly type I collagen associated with excessive collagen deposition, plays a pivotal role in the progressive remodeling of the lung parenchyma to chronic exertional dyspnea for both IPF and COPD. To address the pressing need for noninvasive early diagnosis and drug treatment monitoring of pulmonary fibrosis, we report the development of human collagen-targeted protein MRI contrast agent (hProCA32.collagen) to specifically bind to collagen I overexpressed in multiple lung diseases. When compared to clinically approved Gd3+ contrast agents, hProCA32.collagen exhibits significantly better r1 and r2 relaxivity values, strong metal binding affinity and selectivity, and transmetalation resistance. Here, we report the robust detection of early and late-stage lung fibrosis with stage-dependent MRI signal-to-noise ratio (SNR) increase, with good sensitivity and specificity, using a progressive bleomycin-induced IPF mouse model. Spatial heterogeneous mapping of usual interstitial pneumonia (UIP) patterns with key features closely mimicking human IPF, including cystic clustering, honeycombing, and traction bronchiectasis, were noninvasively detected by multiple MR imaging techniques and verified by histological correlation. We further report the detection of fibrosis in the lung airway of an electronic cigarette-induced COPD mouse model, using hProCA32.collagen-enabled precision MRI (pMRI), and validated by histological analysis. The developed hProCA32.collagen is expected to have strong translational potential for the noninvasive detection and staging of lung diseases, and facilitating effective treatment to halt further chronic lung disease progression.

[Consensus guideline on the interdisciplinary diagnosis of interstitial lung diseases]

The evaluation of a patient with interstitial lung disease (ILD) includes assessment of clinical, radiological, and often histopathological data. As there were no specific recommendations to guide the evaluation of patients under the suspicion of an ILD within the German practice landscape, this position statement from an interdisciplinary panel of ILD experts provides guidance related to the diagnostic modalities which should be used in the evaluation of ILD. This includes clinical assessment rheumatological evaluation, radiological examinations, histopathologic sampling and the need for a final discussion in a multidisciplinary team.

Impact of interstitial lung abnormalities on postoperative pulmonary complications and survival of lung cancer

BACKGROUND

Interstitial lung abnormalities (ILAs) are associated with the risk of lung cancer and its mortality. However, the impact of ILA on treatment-related complications and survival in patients who underwent curative surgery is still unknown.

RESEARCH QUESTION

This study aimed to evaluate the significance of the presence of computed tomography-diagnosed ILA and histopathologically matched interstitial abnormalities on postoperative pulmonary complications (PPCs) and the long-term survival of patients who underwent surgical treatment for lung cancer.

STUDY DESIGN AND METHODS

A matched case-control study was designed to compare PPCs and mortality among 50 patients with ILA, 50 patients with idiopathic pulmonary fibrosis (IPF) and 200 controls. Cases and controls were matched by sex, age, smoking history, tumour location, the extent of surgery, tumour histology and pathological TNM stage.

RESULTS

Compared with the control group, the OR of the prevalence of PPCs increased to 9.56 (95% CI 2.85 to 32.1, p<0.001) in the ILA group and 56.50 (95% CI 17.92 to 178.1, p<0.001) in the IPF group. The 5-year overall survival (OS) rates of the control, ILA and IPF groups were 76% (95% CI 71% to 83%), 52% (95% CI 37% to 74%) and 32% (95% CI 19% to 53%), respectively (log-rank p<0.001). Patients with ILA had better 5-year OS than those with IPF (log-rank p=0.046) but had worse 5-year OS than those in the control group (log-rank p=0.002).

CONCLUSIONS

The presence of radiological and pathological features of ILA in patients with lung cancer undergoing curative surgery was associated with frequent complications and decreased survival.

Digital quantification of p16-positive foci in fibrotic interstitial lung disease is associated with a phenotype of idiopathic pulmonary fibrosis with reduced survival

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is associated with increased expression of cyclin-dependent kinase inhibitors such as p16 and p21, and subsequent induction of cell cycle arrest, cellular senescence, and pro-fibrotic gene expression. We sought to link p16-expression with a diagnosis of IPF or other fibrotic interstitial lung diseases (ILDs), radiographic pattern, senescent foci-specific gene expression, antifibrotic therapy response, and lung transplant (LTx)-free survival.

METHODS

Eighty-six cases of fibrosing ILD were identified with surgical lung biopsy. Immunohistochemistry for p16 was performed on sections with the most active fibrosis. p16-positive foci (loose collection of p16-positive fibroblasts with overlying p16-positive epithelium) were identified on digital slides and quantified. Cases were scored as p16-low (≤ 2.1 foci per 100 mm²) or p16-high (> 2.1 foci per 100 mm²). Twenty-four areas including senescent foci, fibrotic and normal areas were characterized using in situ RNA expression analysis with digital spatial profiling (DSP) in selected cases.

RESULTS

The presence of p16-positive foci was specific for the diagnosis of IPF, where 50% of cases expressed any level of p16 and 26% were p16-high. There was no relationship between radiographic pattern and p16 expression. However, there was increased expression of cyclin-dependent kinase inhibitors, collagens and matrix remodeling genes within p16-positive foci, and cases with high p16 expression had shorter LTx-free survival. On the other hand, antifibrotic therapy was significantly protective. DSP demonstrated that fibroblastic foci exhibit transcriptional features clearly distinct from that of normal-looking and even fibrotic areas.

CONCLUSIONS

We demonstrated the potential clinical applicability of a standardized quantification of p16-positive fibroblastic foci. This method identifies an IPF phenotype associated with foci-specific upregulation of senescence-associated and matrix remodeling gene expression. While these patients have reduced LTx-free survival, good response to antifibrotic therapies was observed in those who were treated.

Interobserver agreement regarding the Fleischner Society diagnostic criteria for usual interstitial pneumonia patterns on computed tomography

Objective

To assess interobserver agreement among radiologists regarding the current Fleischner Society diagnostic criteria for usual interstitial pneumonia (UIP) patterns on computed tomography (CT).

Materials and Methods

Using the Fleischner Society criteria for UIP CT patterns, five raters, working independently, categorized the high-resolution CT (HRCT) scans of 44 patients with interstitial lung disease who underwent lung biopsy. The raters also evaluated the presence, extent, and distribution of the most relevant imaging findings, as well as indicating their level of confidence in the most likely diagnosis and in up to three diagnostic hypotheses.

Results

There was moderate to substantial interobserver agreement regarding the UIP patterns on HRCT—kappa statistic (κ) = 0.59-0.61. Interobserver agreement for the binary scores was substantial (κ = 0.77-0.79), whereas that for the presence of honeycombing was almost perfect (κ = 0.81-0.96). There was agreement regarding at least one of the three diagnostic hypotheses in only 36.4% of the cases. For the level of confidence in the most likely diagnosis, there was only slight to fair agreement (κ = 0.19-0.21).

Conclusion

Interobserver agreement regarding the current Fleischner Society CT criteria for UIP was moderate to substantial among raters with varying levels of experience. There was only slight to fair agreement regarding the diagnostic hypotheses and for the level of confidence in the most likely diagnosis.

Microbiota and IPF: hidden and detected relationships

Lung microbiota (LM) is an interesting new way to consider and redesign pathogenesis and possible therapeutic approach to many lung diseases, such as idiopathic pulmonary fibrosis (IPF), which is an interstitial pneumonia with bad prognosis. Chronic inflammation is the basis but probably not the only cause of lung fibrosis and although the risk factors are not completely clear, endogenous factors (e.g. gastroesophageal reflux) and environmental factors like cigarette smoking, industrial dusts, and precisely microbial agents could contribute to the IPF development. It is well demonstrated that many bacteria can cause epithelial cell injuries in the airways through induction of a host immune response or by activating flogosis mediators following a chronic, low-level antigenic stimulus. This persistent host response could influence fibroblast responsiveness suggesting that LM may play a role in repetitive alveolar injury in IPF. We reviewed literature regarding not only bacteria but also the role of virome and mycobiome in IPF. In fact, some viruses such as hepatitis C virus or certain fungi could be etiological agents or co-factors in the IPF progress. We aim to illustrate how the cross-talk between different local microbiotas throughout specific axis and immune modulation governed by microorganisms could be at the basis of lung dysfunctions and IPF development. Finally, since the future direction of medicine will be personalized, we suggest that the analysis of LM could be a goal to research new therapies also in IPF.

Disease pathology in fibrotic interstitial lung disease: is it all about usual interstitial pneumonia?

The interstitial pneumonias comprise a diverse group of diseases that are typically defined by their cause (either idiopathic or non-idiopathic) and their distinct histopathological features, for which radiology, in the form of high-resolution CT, is often used as a surrogate. One trend, fuelled by the failure of conventional therapies in a subset of patients and the broad-spectrum use of antifibrotic therapies, has been the focus on the progressive fibrosing phenotype of interstitial lung disease. The histological pattern, known as usual interstitial pneumonia, is the archetype of progressive fibrosis. However, it is clear that progressive fibrosis is not exclusive to this histological entity. Techniques including immunohistochemistry and single-cell RNA sequencing are providing pathogenetic insights and, if integrated with traditional histopathology, are likely to have an effect on the pathological classification of interstitial lung disease. This review, which focuses on the histopathology of interstitial lung disease and its relationship with progressive fibrosis, asks the question: is it all about usual interstitial pneumonia?

Deep Learning of Computed Tomography Virtual Wedge Resection for Prediction of Histologic Usual Interstitial Pneumonitis

Rationale: The computed tomography (CT) pattern of definite or probable usual interstitial pneumonia (UIP) can be diagnostic of idiopathic pulmonary fibrosis and may obviate the need for invasive surgical biopsy. Few machine-learning studies have investigated the classification of interstitial lung disease (ILD) on CT imaging, but none have used histopathology as a reference standard.Objectives: To predict histopathologic UIP using deep learning of high-resolution computed tomography (HRCT).Methods: Institutional databases were retrospectively searched for consecutive patients with ILD, HRCT, and diagnostic histopathology from 2011 to 2014 (training cohort) and from 2016 to 2017 (testing cohort). A blinded expert radiologist and pulmonologist reviewed all training HRCT scans in consensus and classified HRCT scans based on the 2018 American Thoracic Society/European Respriatory Society/Japanese Respiratory Society/Latin American Thoracic Association diagnostic criteria for idiopathic pulmonary fibrosis. A convolutional neural network (CNN) was built accepting 4 × 4 × 2 cm virtual wedges of peripheral lung on HRCT as input and outputting the UIP histopathologic pattern. The CNN was trained and evaluated on the training cohort using fivefold cross validation and was then tested on the hold-out testing cohort. CNN and human performance were compared in the training cohort. Logistic regression and survival analyses were performed.Results: The CNN was trained on 221 patients (median age 60 yr; interquartile range [IQR], 53-66), including 71 patients (32%) with UIP or probable UIP histopathologic patterns. The CNN was tested on a separate hold-out cohort of 80 patients (median age 66 yr; IQR, 58-69), including 22 patients (27%) with UIP or probable UIP histopathologic patterns. An average of 516 wedges were generated per patient. The percentage of wedges with CNN-predicted UIP yielded a cross validation area under the curve of 74% for histopathological UIP pattern per patient. The optimal cutoff point for classifying patients on the training cohort was 16.5% of virtual lung wedges with CNN-predicted UIP and resulted in sensitivity and specificity of 74% and 58%, respectively, in the testing cohort. CNN-predicted UIP was associated with an increased risk of death or lung transplantation during cross validation (hazard ratio, 1.5; 95% confidence interval, 1.1-2.2; P = 0.03).Conclusions: Virtual lung wedge resection in patients with ILD can be used as an input to a CNN for predicting the histopathologic UIP pattern and transplant-free survival.

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.

Heme Oxygenase-1 in Patients With Interstitial Lung Disease: A Review of the Clinical Evidence

The clinical course and rate of progression of interstitial lung disease (ILD) are extremely variable among patients. For the purpose of monitoring disease activity, ILD diagnosis, and predicting disease prognosis, there are various biomarkers, including symptoms, physiological, radiological, and pathological findings, and peripheral blood and bronchoalveolar lavage fluid results. Of these, blood biomarkers such as sialylated carbohydrate antigen, surfactant proteins-A and -D, CC-chemokine ligand 18, matrix metalloprotease-1 and -7, CA19-9, and CA125 have been previously proposed. In the future, heme oxygenase-1 (HO-1) may also become a candidate ILD biomarker; it is a 32-kDa heat shock protein converting heme to carbon monoxide, biliverdin/bilirubin, and free iron to play a role in the pulmonary cytoprotective reaction in response to various stimuli. Recent research suggests that HO-1 can increase in lung tissues of patients with ILD, reflecting anti-inflammatory M2 macrophage activation, and the measurement of HO-1 levels in peripheral blood can be useful for evaluating the severity of lung damage in ILD and for predicting subsequent fibrosis formation.

Ice Capades: Skating Around Current Practice of Cryobiopsy for ILD

BACKGROUND

Transbronchial lung cryobiopsy (TBLC) has been proposed as a potentially safer alternative in the diagnosis of interstitial lung disease. The current practice of TBLC is unknown as most published data come from case reports, case series, and a few trials. The authors report the practice patterns of TBLC on the basis of survey responses.

METHODS

The authors created an anonymous online survey to assess how proceduralists evaluate patients, perform, and manage complications of TBLC. Surveys were distributed through social media and e-mail distribution lists from the American Association of Bronchology and Interventional Pulmonology and the Society of Advanced Bronchoscopists. Aggregated responses are reported as counts, percentages, and averages.

RESULTS

Surveys show significant variation in parameters providers use to assess appropriate patients for procedures, how specific aspects of TBLC are performed, and how complications and results are managed.

CONCLUSION

This is the first and largest survey of providers describing the current large variation in the use of cryobiopsy for the evaluation of interstitial lung disease. The standardized practice is essential to understand the true diagnostic accuracy or rate of complications related to TBLC.

A single-institution study of concordance of pathological diagnoses for interstitial lung diseases between pre-transplantation surgical lung biopsies and lung explants

BACKGROUND

By comparing diagnoses made by pre-transplant surgical lung biopsy (SLB) and the final pathologic diagnosis of the explanted pathology (EP), we aimed to study the factors that could impact pathologic diagnoses in patients with interstitial lung disease (ILD).

METHODS

We retrospectively reviewed the lung transplant database at Cleveland Clinic [01/01/2006-12/31/2013] to include all lung transplant recipients with a prior diagnosis of ILD. Two pulmonary pathologists independently reviewed each SLB and lung explant. The diagnoses were labeled as concordant (same diagnosis on SLB and explant) or discordant (diagnosis on SLB and explant were different) by consensus.

RESULTS

Of 389 patients transplanted for ILD, 217 had an SLB before transplant. Pathological diagnoses were concordant in 190 patients (87.6%) [165 UIP (86.8%), 13 NSIP (6.8%), 8 CHP (4.2%) and 4 other diagnoses (2.1%). In 27 cases (12.4%), the diagnosis on SLB differed from EP. 8/27 were diagnosed with UIP on SLB and of these, 5 were re-classified as NSIP. 14/19 (73.7%) patients with a SLB diagnosis "other than UIP" were re-categorized as UIP based on explant. Discordant cases had a greater time between SLB and EP than concordant cases (1553 days vs 1248 days).

CONCLUSIONS

The pathologic diagnosis of ILD by SLB prior to lung transplant is accurate in most patients, but may be misleading in a small subset of patients. The majority of discordant cases that were reclassified as UIP could be due to a sampling error, or perhaps, an increased time from the date of the SLB to transplant. Future studies examining how multidisciplinary consensus diagnosis affects this discordance are necessary.

The Role of Immunity and Inflammation in IPF Pathogenesis

IPF is thought to be a consequence of repetitive micro-injury to ageing alveolar epithelium by factors including tobacco smoke, environmental exposures, microbial colonisation/infection, microaspiration, endoplasmic reticulum stress and oxidative stress, with resultant aberrant wound healing. Though partially effective antifibrotic therapies have focused attention away from older inflammation-based hypotheses for IPF pathogenesis, innate and adaptive immune cells and processes may play roles potentially in initiation and/or disease progression in IPF and/or in IPF acute exacerbations, based on multiple lines of evidence. Members of the Toll-like family of innate immune receptors have been implicated in IPF pathogenesis, including a potential modulatory role for the lung microbiome. A variety of chemokines are associated with the presence of IPF, and an imbalance of angiogenic chemokines has been linked to vascular remodelling in the disease. Subsets of circulating monocytes, including fibrocytes and segregated-nucleus-containing atypical monocytes (SatM), have been identified that may facilitate progression of fibrosis, and apoptosis-resistant pulmonary macrophages have been shown to demonstrate pro-fibrotic potential. Inflammatory cells that have been somewhat dismissed as irrelevant to IPF pathogenesis are being re-evaluated in light of new mechanistic data, such as activated neutrophils which release their chromatin in a process termed NETosis, which appears to mediate age-related murine lung fibrosis. A greater understanding is needed of the role of lymphoid aggregates, a histologic feature of IPF lungs found in close proximity to fibroblastic foci and highly suggestive of the presence of chronic immune responses in IPF, as are well-characterised activated circulating T lymphocytes and distinct autoantibodies that have been observed in IPF. There is a pressing need to discern whether or not the indisputably present immune dysregulation of IPF constitutes cause or effect in the ongoing search for more effective therapeutic strategies.

[Chronic diseases, precancer, and cancer of the lung, which are associated with pathology of the club cells of respiratory and terminal bronchioles]

The review of the literature deals with the participation of Clara cells now called club cells (CCs) of the epithelium in the respiratory and terminal bronchioles in the pathogenesis and morphogenesis of chronic inflammatory diseases, precancer, and cancer of the lung, which develop in the respiratory segments. The review summarizes data on the histophysiology of CCs and their participation in the pathogenesis and morphogenesis of chronic interstitial lung diseases, pneumoconiosis, chronic obstructive diseases, adenomatosis, and adenocarcinoma of the lung. In this area, there is a bronchioloalveolar junction area (BAJA), one of the most important stem cell niches. CCs are located in the BAJA; they are progenitor tissue stem cells and play an important role in the regeneration of the epithelium of the respiratory bronchioles and alveoli. Pathology of CCs in the BAJA leads to the maintenance of chronic inflammation, to the destruction of the lung elastic frame, and to impaired epithelial regeneration, interstitial fibrosis, and adenomatosis. In this case, decompensated inflammation, pathological regeneration, and fibrosis develop, which, along with the action of carcinogenic agents, can contribute to the accumulation of mutations and epigenetic rearrangements in the CCs, which subsequently results in atypical adenomatous hyperplasia and adenocarcinoma of the lung.

Reprint of: Nonspecific interstitial pneumonia: pathologic features and clinical implications

Nonspecific interstitial pneumonia (NSIP) is a form of chronic interstitial pneumonia that should be separated from the other idiopathic interstitial pneumonias, including most importantly, usual interstitial pneumonia (UIP). Diagnosis is predicated on identification of characteristic findings in a surgical lung biopsy in the appropriate clinical and radiological context. Affected patients may have a variety of underlying or associated conditions, although most have a form of idiopathic lung disease associated with a more favorable prognosis than UIP/idiopathic pulmonary fibrosis (IPF). Keys to distinguishing NSIP from UIP include absence of heterogeneous lung involvement, architectural distortion in the form of fibrotic scarring and/or honeycomb change, and fibroblast foci in NSIP.

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.

Diagnosis of Idiopathic Pulmonary Fibrosis "Pragmatic Challenges in Clinical Practice"

The past few years have signaled a major breakthrough on the management of idiopathic pulmonary fibrosis (IPF). Finally, we have drugs in our arsenal able to slow down the inexorable disease natural course. On the other hand, the latter evidence has increased the responsibility for a timely and accurate diagnosis. Establishment of IPF diagnosis directly affects the choice of appropriate treatment. The current diagnostic guidelines represent a major step forward providing an evidence-based road map; yet, clinicians are encountering major diagnostic dilemmas that inevitably affect therapeutic decisions. This review article aims to summarize the current state of knowledge on the diagnostic procedure of IPF based on the current guidelines and discuss pragmatic difficulties and challenges encountered by clinicians with regards to their applicability in the everyday clinical practice.

Gene expression profiling of idiopathic interstitial pneumonias (IIPs): identification of potential diagnostic markers and therapeutic targets

BACKGROUND

Chronic fibrosing idiopathic interstitial pneumonia (IIP) is characterized by alveolar epithelial damage, activation of fibroblast proliferation, and loss of normal pulmonary architecture and function. This study aims to investigate the genetic backgrounds of IIP through gene expression profiling and pathway analysis, and to identify potential biomarkers that can aid in diagnosis and serve as novel therapeutic targets.

METHODS

RNA extracted from lung specimens of 12 patients with chronic fibrosing IIP was profiled using Illumina Human WG-6 v3 BeadChips, and Ingenuity Pathway Analysis was performed to identify altered functional and canonical signaling pathways. For validating the results from gene expression analysis, immunohistochemical staining of 10 patients with chronic fibrosing IIP was performed.

RESULTS

Ninety-eight genes were upregulated in IIP patients relative to control subjects. Some of the upregulated genes, namely desmoglein 3 (DSG3), protocadherin gamma-A9 (PCDHGA9) and discoidin domain-containing receptor 1 (DDR1) are implicated in cell-cell interaction and/or adhesion; some, namely collagen type VII, alpha 1 (COL7A1), contactin-associated protein-like 3B (CNTNAP3B) and mucin-1 (MUC1) are encoding the extracellular matrix molecule or the molecules involved in cell-matrix interactions; and the others, namely CDC25C and growth factor independent protein 1B (GFI1B) are known to affect cell proliferation by affecting the progression of cell cycle or regulating transcription. According to pathway analysis, alternated pathways in IIP were related to cell death and survival and cellular growth and proliferation, which are more similar to cancer than to inflammatory response and immunological diseases. Using immunohistochemistry, we further validate that DSG3, the most highly upregulated gene, shows higher expression in chronic fibrosing IIP lung as compared to control lung.

CONCLUSION

We identified several genes upregulated in chronic fibrosing IIP patients as compared to control, and found genes and pathways implicated in cancer, rather than in inflammatory or immunological disease to play important roles in the pathogenesis of IIPs. Moreover, DSG3 is a novel potential biomarker for chronic fibrosing IIP with its significantly high expression in IIP lung.

Multidisciplinary evaluation of interstitial lung diseases: current insights: Number 1 in the Series "Radiology" Edited by Nicola Sverzellati and Sujal Desai

Multidisciplinary team (MDT) diagnosis is regarded as the diagnostic reference standard for interstitial lung disease (ILD). Several studies have reported that MDT diagnosis is associated with higher levels of diagnostic confidence and better interobserver agreement when compared to the individual components of the MDT in isolation. Although this recommendation is widely accepted, no guideline statement specifies what constitutes an MDT meeting and how its participants should govern it. Furthermore, the precise role of an MDT meeting in the setting of ILD may vary from one group to another. For example, in some cases, the meeting will confine its discussion to characterising the disease and formulating diagnosis. In others, management decisions may also be part of the discussion. Surprisingly, there is no consensus on how MDT diagnosis is validated. As multidisciplinary evaluation contains all the available clinical information on an individual patient, there is no reference standard against which the veracity of MDT diagnosis can be tested. Finally, many of these uncertainties surrounding MDT meeting practice are unlikely to be answered by traditional evidence-based studies, which create difficulties when generating guideline recommendations. There is clearly a need for expert consensus on what constitutes acceptable MDT meeting practice. This consensus will need to be flexible to accommodate the variability in resources available to fledgling MDT groups and the variable nature of patients requiring discussion.

Bronchoscopic Lung Cryobiopsy Increases Diagnostic Confidence in the Multidisciplinary Diagnosis of Idiopathic Pulmonary Fibrosis

RATIONALE

Surgical lung biopsy is often required for a confident multidisciplinary diagnosis of idiopathic pulmonary fibrosis (IPF). Alternative, less-invasive biopsy methods, such as bronchoscopic lung cryobiopsy (BLC), are highly desirable.

OBJECTIVES

To address the impact of BLC on diagnostic confidence in the multidisciplinary diagnosis of IPF.

METHODS

In this cross-sectional study we selected 117 patients with fibrotic interstitial lung disease without a typical usual interstitial pneumonia pattern on high-resolution computed tomography. All cases underwent lung biopsies: 58 were BLC, and 59 were surgical lung biopsy (SLB). Two clinicians, two radiologists, and two pathologists sequentially reviewed clinical-radiologic findings and biopsy results, recording at each step in the process their diagnostic impressions and confidence levels.

MEASUREMENTS AND MAIN RESULTS

We observed a major increase in diagnostic confidence after the addition of BLC, similar to SLB (from 29 to 63%, P = 0.0003 and from 30 to 65%, P = 0.0016 of high confidence IPF diagnosis, in the BLC group and SLB group, respectively). The overall interobserver agreement in IPF diagnosis was similar for both approaches (BLC overall kappa, 0.96; SLB overall kappa, 0.93). IPF was the most frequent diagnosis (50 and 39% in the BLC and SLB group, respectively; P = 0.23). After the addition of histopathologic information, 17% of cases in the BLC group and 19% of cases in the SLB group, mostly idiopathic nonspecific interstitial pneumonia and hypersensitivity pneumonitis, were reclassified as IPF.

CONCLUSIONS

BLC is a new biopsy method that has a meaningful impact on diagnostic confidence in the multidisciplinary diagnosis of interstitial lung disease and may prove useful in the diagnosis of IPF. This study provides a robust rationale for future studies investigating the diagnostic accuracy of BLC compared with SLB.

Surgical Lung Biopsy for Interstitial Lung Diseases

This review addresses common questions regarding the role of surgical lung biopsy (SLB) in the diagnosis and treatment of interstitial lung disease (ILD). We specifically address when a SLB can be diagnostic as well as when it may be avoided; for example, when the combination of the clinical context and the imaging pattern seen on high-resolution CT (HRCT) chest scans can provide a confident diagnosis. Existing studies on the diagnostic utility as well as the complications associated with SLB are reviewed; also reviewed are the performance characteristics and reliability of HRCT scans of the chest in predicting the underlying histopathologic findings of the lung. The review is formatted in the form of answers to questions that clinicians regularly ask when considering an SLB in a patient with ILD.

The Value of a Multidisciplinary Approach to the Diagnosis of Usual Interstitial Pneumonitis and Idiopathic Pulmonary Fibrosis: Radiology, Pathology, and Clinical Correlation

OBJECTIVE

Multidisciplinary discussion is essential in establishing the diagnosis of idiopathic pulmonary fibrosis (IPF) and in determining prognosis.

CONCLUSION

The CT and histopathologic correlate for IPF is usual interstitial pneumonitis (UIP). If a high-confidence diagnosis of UIP is made on CT, IPF is almost always the diagnosis, obviating lung biopsy. If a confident diagnosis of UIP cannot be made on CT, further assessment with lung biopsy and multidisciplinary discussion are often necessary to achieve a confident final diagnosis.

Distinct characteristics of pleuroparenchymal fibroelastosis with usual interstitial pneumonia compared with idiopathic pulmonary fibrosis

BACKGROUND

Pleuroparenchymal fibroelastosis (PPFE) is a rare form of interstitial pneumonia and sometimes coexists with a histologic usual interstitial pneumonia (UIP) pattern. This study aimed to describe the distinct clinical features of PPFE with UIP pattern compared with idiopathic pulmonary fibrosis (IPF).

METHODS

We conducted a retrospective review of the medical records of 110 consecutive patients with IPF with a histologic UIP pattern on surgical lung biopsy specimen. Patients meeting radiologic criteria for the diagnosis of PPFE based on high-resolution CT scan and with a histologic UIP pattern were included.

RESULTS

Nine of eleven patients meeting radiologic criteria for the diagnosis of PPFE were histologically confirmed as having PPFE with UIP pattern. The PPFE with UIP pattern group showed a significantly higher residual volume (1.8 L vs 1.3 L, P < .01), higher Paco2 (44.6 mm Hg vs 41.7 mm Hg, P = .04), and higher complication rate of pneumothorax and pneumomediastinum than the 99 patients with IPF/UIP. The ratio of anteroposterior to transthoracic diameter in patients with PPFE with UIP pattern was significantly lower than that in patients with IPF/UIP (P = .04). Survival time tended to be shorter in patients with PPFE with UIP pattern.

CONCLUSIONS

The results support the view that PPFE with UIP pattern is a disease entity distinct from IPF/UIP and may well be classified as PPFE.

Nonspecific interstitial pneumonia and usual interstitial pneumonia: comparison of the clinicopathologic features and prognosis

BACKGROUND

Nonspecific interstitial pneumonia (NSIP) has recently been proposed as a histologic type of idiopathic interstitial pneumonia (IIP), but its broad spectrum of clinicopathologic findings and variable prognosis are poorly understood. It is particularly unclear how NSIP and usual interstitial pneumonia (UIP) are related. The present study investigated the clinicopathologic features and prognosis of NSIP, and its differential diagnosis from UIP.

METHODS

The clinicopathologic findings and prognosis in 21 NSIP and 18 UIP patients who underwent surgical or video-assisted thoracoscopic lung biopsy were reviewed.

RESULTS

NSIP was more frequent in women and showed nonspecific clinical manifestations. High-resolution computed tomography (HRCT) demonstrated ground-glass, net-like, and patchy attenuation in both lungs. Semiquantitative HRCT showed a median fibrosis score of 3 (range, 0 to 7) in NSIP patients and 5 (range, 2 to 7) in UIP patients (P<0.01). On histopathologic examination, NSIP cases were heterogeneous and the findings could be categorized into cellular and fibrosing patterns. The mean age of the NSIP and UIP patients was 48 and 60 years, respectively. The frequencies of fibroblast foci, myogelosis, honeycomb lesions, and pulmonary structural destruction in NSIP and UIP patients were 16.7% and 100% (P<0.001), 22.2% and 85.7% (P<0.05), 16.7% and 92.9% (P<0.001), and 27.8% and 100% (P<0.05), respectively. The responses to glucocorticoid treatment and the prognosis were significantly greater in NSIP than those in UIP.

CONCLUSIONS

NSIP was difficult to be differentiated from UIP by general clinical manifestations, but HRCT can be helpful for this purpose. Definitive diagnosis depends on the results of surgical lung biopsy.

Beyond the diagnosis of idiopathic pulmonary fibrosis; the growing role of systems biology and stratified medicine

PURPOSE OF REVIEW

Idiopathic pulmonary fibrosis (IPF) is a progressive, invariably fatal condition with a median survival from diagnosis of only 3 years. Despite improvements in disease understanding, challenges remain in establishing a diagnosis and predicting prognosis in individual patients. Furthermore, limited understanding of the key pathogenetic mechanisms driving disease is hampering development of new therapies. This review outlines progress that has been made in applying systems biology to IPF and the insights into disease pathogenesis, diagnosis and monitoring that this research is providing.

RECENT FINDINGS

Large-scale genome-wide association studies have highlighted polymorphisms in genes involved in epithelial integrity and host defense including MUC5B and TOLLIP. Whole blood transcriptomics points towards changes in immune cell regulation that influence the progression of fibrosis. Proteomic studies have identified serum proteins, including matrix metalloproteinase 7 and CC chemokine ligand (CCL)-18, which associate with disease severity and predict prognosis.

SUMMARY

Use of molecular research techniques in large populations of well-phenotyped patients is leading to major advances in understanding of IPF. As new treatments for IPF emerge, it is to be hoped that careful application of these findings will enable the targeting of therapy to individuals based on the predominant mechanisms driving progression of their disease.

Transbronchial lung cryobiopsy in the diagnosis of fibrotic interstitial lung diseases

BACKGROUND

Histology is a key element for the multidisciplinary diagnosis of fibrotic diffuse parenchymal lung diseases (f-DPLD) when the clinical-radiological picture is nondiagnostic. Transbronchial lung cryobiopsy (TBLC) have been shown to be useful for obtaining large and well-preserved biopsies of lung parenchyma, but experience with TBLC in f-DPLD is limited.

OBJECTIVES

To evaluate safety, feasibility and diagnostic yield of TBLC in f-DPLD.

METHOD

Prospective study of 69 cases of TBLC using flexible cryoprobe in the clinical-radiological setting of f-DPLD with nondiagnostic high resolution computed tomography (HRCT) features.

RESULTS

SAFETY

pneumothorax occurred in 19 patients (28%). One patient (1.4%) died of acute exacerbation. Feasibility: adequate cryobiopsies were obtained in 68 cases (99%). The median size of cryobiopsies was 43.11 mm(2) (range, 11.94-76.25). Diagnostic yield: among adequate TBLC the pathologists were confident ("high confidence") that histopathologic criteria sufficient to define a specific pattern in 52 patients (76%), including 36 of 47 with UIP (77%) and 9 nonspecific interstitial pneumonia (6 fibrosing and 3 cellular), 2 desquamative interstitial pneumonia/respiratory bronchiolitis-interstitial lung disease, 1 organizing pneumonia, 1 eosinophilic pneumonia, 1 diffuse alveolar damage, 1 hypersensitivity pneumonitis and 1 follicular bronchiolitis. In 11 diagnoses of UIP the pathologists were less confident ("low confidence"). Agreement between pathologists in the detection of UIP was very good with a Kappa coefficient of 0.83 (95% CI, 0.69-0.97). Using the current consensus guidelines for clinical-radiologic-pathologic correlation 32% (20/63) of cases were classified as Idiopathic Pulmonary Fibrosis (IPF), 30% (19/63) as possible IPF, 25% (16/63) as other f-DPLDs and 13% (8/63) were unclassifiable.

CONCLUSIONS

TBLC in the diagnosis of f-DPLD appears safe and feasible. TBLC has a good diagnostic yield in the clinical-radiological setting of f-DPLD without diagnostic HRCT features of usual interstitial pneumonia. Future studies should consider TBLC as a potential alternative to SLBx in f-DPLD.

Molecular magnetic resonance imaging of pulmonary fibrosis in mice

Idiopathic pulmonary fibrosis is a chronic, progressive, fibrosing interstitial pneumonia of unknown cause resulting in dyspnea and functional decline until death. There are currently no effective noninvasive tools to monitor disease progression and response to treatment. The objective of the present study was to determine whether molecular magnetic resonance imaging of the lung using a probe targeted to type I collagen could provide a direct, noninvasive method for assessment of pulmonary fibrosis in a mouse model. Pulmonary fibrosis was generated in mice by transtracheal instillation of bleomycin (BM). Six cohorts were imaged before and immediately after intravenous administration of molecular imaging probe: (1) BM plus collagen-targeted probe, EP-3533; (2) sham plus EP-3533; (3) BM plus nonbinding control probe, EP-3612; (4) sham plus EP-3612; (5) BM plus EP-3533 imaged early; and (6) BM plus EP-3533 imaged late. Signal-to-noise ratio (SNR) enhancement was quantified in the lungs and muscle. Lung tissue was subjected to pathologic scoring of fibrosis and analyzed for gadolinium and hydroxyproline. BM-treated mice had 35% higher lung collagen than sham mice (P < 0.0001). The SNR increase in the lungs of fibrotic mice after EP-3533 administration was twofold higher than in sham animals and twofold higher than in fibrotic or sham mice that received control probe, EP-3612 (P < 0.0001). The SNR increase in muscle was similar for all cohorts. For EP-3533, we observed a strong, positive, linear correlation between lung SNR increase and hydroxyproline levels (r = 0.72). Collagen-targeted probe EP-3533-enhanced magnetic resonance imaging specifically detects pulmonary fibrosis in a mouse model of disease.