Heterogeneity in Unclassifiable Interstitial Lung Disease. A Systematic Review and Meta-Analysis

Interdisciplinary Diagnosis and Management of Patients With Interstitial Lung Disease and Connective Tissue Disease

A diagnosis of interstitial lung diseases (ILD) can be challenging, and the identification of an associated connective tissue disease (CTD) is crucial to estimate prognosis and to establish the optimal treatment approach. Diagnostic delay, limited expertise, and fragmented care are barriers that impede the delivery of comprehensive health care for patients with rare, complex, and multiorgan diseases such as CTD and ILD. In this article, we present our perspective on the interdisciplinary diagnosis and interprofessional treatment of patients with ILD and suspected CTD or CTD at risk of ILD. We outline the structure of our service, delineating the roles and responsibilities of the team members. Additionally, we provide an overview of our patient population, including diagnostic approaches and specific treatments, and illustrate a patient case. Furthermore, we focus on specific benefits and challenges of joint interdisciplinary and interprofessional patient consultations. The importance of rheumatology and pulmonology assessments in specific patient populations is emphasized. Finally, we explore future directions and discuss potential strategies to improve care delivery for patients with CTD-associated ILD.

Immune mechanisms in fibrotic interstitial lung disease

Fibrotic interstitial lung diseases (fILDs) have poor survival rates and lack effective therapies. Despite evidence for immune mechanisms in lung fibrosis, immunotherapies have been unsuccessful for major types of fILD. Here, we review immunological mechanisms in lung fibrosis that have the potential to impact clinical practice. We first examine innate immunity, which is broadly involved across fILD subtypes. We illustrate how innate immunity in fILD involves a complex interplay of multiple cell subpopulations and molecular pathways. We then review the growing evidence for adaptive immunity in lung fibrosis to provoke a re-examination of its role in clinical fILD. We close with future directions to address key knowledge gaps in fILD pathobiology: (1) longitudinal studies emphasizing early-stage clinical disease, (2) immune mechanisms of acute exacerbations, and (3) next-generation immunophenotyping integrating spatial, genetic, and single-cell approaches. Advances in these areas are essential for the future of precision medicine and immunotherapy in fILD.

A study on the prevalence and prognosis of progressive pulmonary fibrosis: A retrospective observational study

Interstitial lung disease (ILD) encompasses a heterogeneous group of more than 200 diffuse parenchymal lung diseases with various clinical courses. Disease progression is one of the most important prognostic factors, and, the definition of progressive pulmonary fibrosis (PPF) has recently been established. This study aimed to estimate the prevalence, risk factors, and prognosis of PPF among patients with non-idiopathic pulmonary fibrosis (IPF) in real-world practice. A total of 215 patients were retrospectively analyzed between January 2010 and June 2023 at the Haeundae Paik Hospital in the Republic of Korea. According to the criteria proposed in 2022 by Raghu et al, PPF defined as a condition that satisfies 2 or more of the following in the past year: worsening of respiratory symptoms, physiological evidence of disease progression, and radiological evidence of disease progression. The median age of the subjects was 67 years and 63.7% were female. A total of 40% was diagnosed with PPF and connective tissue disease-associated ILD (52.3%) was the most common type, followed by nonspecific interstitial pneumonitis (NSIP) (25.6%) and cryptogenic organizing pneumonitis (16.3%). In multivariate logistic regression for predicting PPF, both the use of steroids and immunosuppressants (OR: 2.57, 95% CI: 1.41-4.67, P = .002) and home oxygen use (OR: 25.17, 95% CI: 3.21-197.24, P = .002) were independent risk factors. During the follow-up period, the mortality rate was significantly higher in the PPF group than in the non-PPF group (24.4% vs 2.3%, P < .001). In the survival analysis using the Cox proportional hazard regression model, disease progression, older age and lower forced vital capacity (FVC) were independent risk factors for mortality. Our study demonstrated that the prevalence of PPF was 40%. Concomitant therapy of steroids with an immunosuppressants and home oxygen use are risk factors for PPF. PPF itself was significantly associated with high mortality rates. Risk factors for mortality were disease progression, older age, and lower FVC.

Disease Behaviour Classification: A pragmatic model for predicting outcomes in Interstitial Lung Disease

BACKGROUND AND OBJECTIVE

The interstitial lung diseases (ILD) are a heterogenous group of disorders with similar clinical presentation, but widely varying prognoses. The use of a pragmatic disease behaviour classification (DBC), first proposed in international guidelines in 2013, categorises diseases into five behavioural classes based on their predicted clinical course. This study aimed to determine the prognostic utility of the DBC in an ILD cohort.

METHODS

Consecutive patients presented at the weekly multidisciplinary meeting (MDM) of a specialist ILD centre were included. MDM consensus was obtained for diagnosis and DBC category (1-5). Baseline and serial clinical and physiological data were collected over the study period (median 3.9 years, range 0-5.4 years). The relationship between DBC and prognostic outcomes was explored.

RESULTS

137 ILD patients, [64 (47%) female] were included with mean age 67.0 ± 1.1 years, baseline FVC% 72.7 ± 1.7, and baseline DLco% 57.8 ± 1.6%. Patients were stratified into DBC by consensus at MDM: DBC1 n = 0 (0%), DBC2 n = 16 (12%), DBC3 n = 10 (7.3%), DBC4 n = 55 (40%), and DBC5 n = 56 (41%). On univariable Cox regression, increasing DBC class was associated with poorer progression-free survival (HR 1.6, 95% CI 1.2-2.0, p < 0.001). On multivariable Cox regression, DBC remained predictive of PFS when combined with age and gender (HR 1.4, 95% CI 1.1-1.9, p = 0.011), baseline FVC% (HR 1.5, 95% CI 1.1-1.8, p = 0.003) and ILD diagnosis (HR 1.6, 95% CI 1.2-2.2, p < 0.0001).

CONCLUSION

DBC as determined at ILD multidisciplinary meeting may be a useful prognostic tool for the management of ILD patients.

Relative incidence of interstitial lung diseases in Brazil

OBJECTIVE

To assess the relative frequency of incident cases of interstitial lung diseases (ILDs) in Brazil.

METHODS

This was a retrospective survey of new cases of ILD in six referral centers between January of 2013 and January of 2020. The diagnosis of ILD followed the criteria suggested by international bodies or was made through multidisciplinary discussion (MDD). The condition was characterized as unclassifiable ILD when there was no specific final diagnosis following MDD or when there was disagreement between clinical, radiological, or histological data.

RESULTS

The sample comprised 1,406 patients (mean age = 61 ± 14 years), and 764 (54%) were female. Of the 747 cases exposed to hypersensitivity pneumonitis (HP)-related antigens, 327 (44%) had a final diagnosis of HP. A family history of ILD was reported in 8% of cases. HRCT findings were indicative of fibrosis in 74% of cases, including honeycombing, in 21%. Relevant autoantibodies were detected in 33% of cases. Transbronchial biopsy was performed in 23% of patients, and surgical lung biopsy, in 17%. The final diagnoses were: connective tissue disease-associated ILD (in 27%), HP (in 23%), idiopathic pulmonary fibrosis (in 14%), unclassifiable ILD (in 10%), and sarcoidosis (in 6%). Diagnoses varied significantly among centers (c2 = 312.4; p < 0.001).

CONCLUSIONS

Our findings show that connective tissue disease-associated ILD is the most common ILD in Brazil, followed by HP. These results highlight the need for close collaboration between pulmonologists and rheumatologists, the importance of detailed questioning of patients in regard with potential exposure to antigens, and the need for public health campaigns to stress the importance of avoiding such exposure.

Characteristics and risk factors of interstitial pneumonia with autoimmune features

BACKGROUND

Interstitial pneumonia with autoimmune features (IPAF) has features of connective tissue disease-associated interstitial lung disease (CTD-ILD), but without meeting criteria for a specific CTD. We compared baseline characteristics, survival, and response to treatment of IPAF to both CTD-ILD and unclassifiable ILD.

METHODS

Measurements were extracted from a prospective registry. Baseline features and survival were compared in IPAF against both CTD-ILD and unclassifiable ILD. Linear trajectory of lung function decline (%-predicted forced vital capacity [FVC%] and diffusion capacity of the lung for carbon monoxide [DLCO%]) before and after initiation of mycophenolate or azathioprine were compared in IPAF against both CTD-ILD and unclassifiable ILD using linear mixed models.

RESULTS

Compared to CTD-ILD (n = 1240), patients with IPAF (n = 128) were older, more frequently male, and had greater smoking history. Compared to unclassifiable ILD (n = 665), patients with IPAF were younger, more frequently female, and had worse baseline lung function. IPAF had higher mortality compared to CTD-ILD and similar risk of mortality compared to unclassifiable ILD. Mycophenolate initiation was associated with stabilization of FVC% and DLCO% in all ILD subtypes except for FVC% in patients with IPAF, and azathioprine initiation with stabilization of FVC% and DLCO% in all ILD subtypes except for FVC% decline in IPAF and DLCO% decline in CTD-ILD.

CONCLUSION

Patients with IPAF had worse survival compared to those with CTD-ILD and similar mortality to unclassifiable ILD, with treatment being associated with stabilization in lung function in all three ILDs. It is uncertain whether IPAF should be considered a distinct ILD diagnostic subgroup.

Positron Emission-Computed Tomography, Cryobiopsy versus Bronchoalveolar Lavage and Computed Tomography Findings for Interstitial Lung Disease: A Long-Term Follow-Up

Background and Objectives: Interstitial lung diseases have always been an issue for pulmonary and rheumatology physicians. Computed tomography scans with a high-resolution protocol and bronchoalveolar lavage have been used along with biochemical blood tests to reach a diagnosis. Materials and Methods: We included 80 patients in total. First, all patients had their diagnosis with computed tomography of the thorax, serological/ immunological blood tests and bronchoalveolar lavage. However; after 3 months, all were divided into 2 groups: those who had bronchoalveolar lavage again and those who had cryobiopsy instead of bronchoalveolar lavage (40/40). Positron emission-computed tomography was also performed upon the first and second diagnosis. The patients' follow-up was 4 years from diagnosis. Results: Patients suffered most from chronic obstructive pulmonary disease (56, 70%), while lung cancer was rarely encountered in the sample (7, 9.75%). Age distribution ranged between 53 and 68 years with a mean value of 60 years. The computed tomography findings revealed 25 patients with typical diagnosis (35.2%), 17 with interstitial pulmonary fibrosis (23.9%) and 11 with probable diagnosis (11%). The cryobiopsy technique led to a new diagnosis in 28 patients (35% of the total sample). Patients who had a new diagnosis with cryobiopsy had a mean survival time of 710 days (<1460). Positron emission-computed tomography SUV uptake was positively associated with the cryobiopsy technique/new disease diagnosis and improved all respiratory functions. Discussion: Positron emission-computed tomography is a tool that can be used along with respiratory functions for disease evaluation. Conclusions: Cryobiopsy is a safe tool for patients with interstitial lung disease and can assist in the diagnosis of interstitial lung diseases. The survival of patients was increased in the cryobiopsy group versus only bronchoalveolar lavage for disease diagnosis.

[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.

Imaging Fibrosis

Tissue injury in nonmalignant human disease can develop from either disproportionate inflammation or exaggerated fibrotic responses. The molecular and cellular fundamental of these 2 processes, their impact on disease prognosis and the treatment concept deviates fundamentally. Consequently, the synchronous assessment and quantification of these 2 processes in vivo is extremely desirable. Although noninvasive molecular techniques such as ¹⁸F-fluorodeoxyglucose PET offer insights into the degree of inflammatory activity, the assessment of the molecular dynamics of fibrosis remains challenging. The ⁶⁸Ga-fibroblast activation protein inhibitor-46 may improve noninvasive clinical diagnostic performance in patients with both fibroinflammatory pathology and long-term CT-abnormalities after severe COVID-19.

HetVis: A Visual Analysis Approach for Identifying Data Heterogeneity in Horizontal Federated Learning

Horizontal federated learning (HFL) enables distributed clients to train a shared model and keep their data privacy. In training high-quality HFL models, the data heterogeneity among clients is one of the major concerns. However, due to the security issue and the complexity of deep learning models, it is challenging to investigate data heterogeneity across different clients. To address this issue, based on a requirement analysis we developed a visual analytics tool, HetVis, for participating clients to explore data heterogeneity. We identify data heterogeneity through comparing prediction behaviors of the global federated model and the stand-alone model trained with local data. Then, a context-aware clustering of the inconsistent records is done, to provide a summary of data heterogeneity. Combining with the proposed comparison techniques, we develop a novel set of visualizations to identify heterogeneity issues in HFL. We designed three case studies to introduce how HetVis can assist client analysts in understanding different types of heterogeneity issues. Expert reviews and a comparative study demonstrate the effectiveness of HetVis.

Prevalence and assessment of frailty in interstitial lung disease - a systematic review and meta-analysis

BACKGROUND

Frailty is a multisystem dysregulation that challenges homeostasis and increases vulnerability towards stressors. In patients with interstitial lung diseases (ILD) frailty is associated with poorer lung function, greater physical impairment, and higher symptom burden. Our understanding of the prevalence of frailty in ILD and consequently its impact on the ILD population is limited.

OBJECTIVE AND METHODS

We aimed to systematically review frailty assessment tools and to determine frailty prevalence across different ILD cohorts. Meta-analyses were used to calculate the pooled prevalence of frailty in the ILD population.

RESULTS

We identified 26 studies (15 full-texts, 11 conference abstracts) including a total of 4614 patients with ILD. The most commonly used frailty assessment tools were the Fried Frailty Phenotype (FFP), the Short Physical Performance Battery (SPPB), and the cumulative Frailty Index (FI). Data allowed for meta-analyses of FFP and SPPB prevalence. The pooled prevalence of frailty was 35% (95% CI 25%-45%) by FFP, and 19% (95% CI 12%-28%) by SPPB.

CONCLUSIONS

Frailty is common in ILD, with considerable variability of frailty prevalence depending on the frailty assessment tool used. These findings highlight the importance of frailty in ILD and the need for a standardized approach to frailty assessment in this population.

Immunomodulatory treatment in unclassifiable interstitial lung disease: A retrospective study of treatment response

BACKGROUND AND OBJECTIVE

The optimal management of unclassifiable Interstitial lung disease (ILD) remains a challenge. The aim of this study was to describe pulmonary function trajectories for patients treated with immunomodulatory therapy and for untreated patients.

METHODS

Clinical information and treatment data were obtained retrospectively at two ILD centres. Pulmonary function data were analysed using (1) mixed effects linear regression models with and without clinical covariates and (2) propensity score matching using gender, age, physiology (GAP) stage, smoking and presence of ground glass opacities.

RESULTS

Sixty-five percent of the 249 patients included received corticosteroids and/or other immunomodulators. Treated patients had lower forced vital capacity (FVC) (72% vs. 83% predicted) and diffusing capacity for carbon monoxide (DLco) (44% vs. 60% predicted). In mixed effects linear regression, the adjusted change in FVC was -0.22%, [-0.34; -0.11], and -0.15% [-0.28;-0.012] for DLco. The difference in pulmonary function decline between treated and untreated patients was insignificant, -0.082% per month, [-0.28; 0.11], p = 0.10 for FVC and -0.14% per month, [-0.36; 0.079], p = 0.15, for DLco. In propensity score matched analysis, the difference in change in FVC was 0.039% per month, p = 0.12, and for DLco, 0.0085% per month, p = 0.7.

CONCLUSION

The pulmonary function trajectories for treated and untreated patients were parallel, despite treated patients having more severe disease at baseline. The persisting differences between the groups suggest no overall effect, although improvement or stabilization may be seen in some patients. Prospective studies are needed to define subsets of patients with unclassifiable interstitial lung disease and their optimal management.

[French practical guidelines for the diagnosis and management of IPF - 2021 update, full version]

BACKGROUND

Since the previous French guidelines were published in 2017, substantial additional knowledge about idiopathic pulmonary fibrosis has accumulated.

METHODS

Under the auspices of the French-speaking Learned Society of Pulmonology and at the initiative of the coordinating reference center, practical guidelines for treatment of rare pulmonary diseases have been established. They were elaborated by groups of writers, reviewers and coordinators with the help of the OrphaLung network, as well as pulmonologists with varying practice modalities, radiologists, pathologists, a general practitioner, a head nurse, and a patients' association. The method was developed according to rules entitled "Good clinical practice" in the overall framework of the "Guidelines for clinical practice" of the official French health authority (HAS), taking into account the results of an online vote using a Likert scale.

RESULTS

After analysis of the literature, 54 recommendations were formulated, improved, and validated by the working groups. The recommendations covered a wide-ranging aspects of the disease and its treatment: epidemiology, diagnostic modalities, quality criteria and interpretation of chest CT, indication and modalities of lung biopsy, etiologic workup, approach to familial disease entailing indications and modalities of genetic testing, evaluation of possible functional impairments and prognosis, indications for and use of antifibrotic therapy, lung transplantation, symptom management, comorbidities and complications, treatment of chronic respiratory failure, diagnosis and management of acute exacerbations of fibrosis.

CONCLUSION

These evidence-based guidelines are aimed at guiding the diagnosis and the management in clinical practice of idiopathic pulmonary fibrosis.

Cellular Imaging Analysis Algorithm-Based Assessment and Prediction of Disease in Patients with Acute Lung Injury

This paper uses cellular imaging analysis algorithms to assess and predict the condition of patients with acute lung injury. Given the unique optical properties of UCNPs, this paper designs a ratiometric upconversion fluorescent nanoprobe for the determination of nitric oxide (NO) content in living cells and tissues. To address the image degradation phenomenon of optical sections, this paper uses a blind deconvolution method to abate the degradation effect caused by the scattered focus surface, thus completing the image recovery. After that, grayscale and binarization are performed using the weighted average method and the Otsu method. In this paper, we propose a migration learning-based Resnet-50 network for the triple classification of unlabeled leukocytes based on the characteristics of cell images acquired by a miniaturized label-free microfluidic cell imaging detection device. The migration learning can rapidly optimize the network parameters, the short connection structure of Resnet-50 is more suitable for feature extraction of unlabeled leukocytes than the InceptionV3 model without a short connection structure, and the accuracy of the Resnet-50 network can reach 94% in the test set. In this paper, we propose two tracking algorithms based on the dynamic Gaussian mixture model and mathematical morphology-based algorithms suitable for cells of different shapes for cell tracking in microscopic images, neuronal cell labeling in fluorescent images, and cell segmentation in mice. These methods have the advantages of low cost, speed, reproducibility, and objectivity, and we hope that their elicitation will be useful for relevant cell biology research.

French practical guidelines for the diagnosis and management of idiopathic pulmonary fibrosis - 2021 update. Full-length version

BACKGROUND

Since the latest 2017 French guidelines, knowledge about idiopathic pulmonary fibrosis has evolved considerably.

METHODS

Practical guidelines were drafted on the initiative of the Coordinating Reference Center for Rare Pulmonary Diseases, led by the French Language Pulmonology Society (SPLF), by a coordinating group, a writing group, and a review group, with the involvement of the entire OrphaLung network, pulmonologists practicing in various settings, radiologists, pathologists, a general practitioner, a health manager, and a patient association. The method followed the "Clinical Practice Guidelines" process of the French National Authority for Health (HAS), including an online vote using a Likert scale.

RESULTS

After a literature review, 54 guidelines were formulated, improved, and then validated by the working groups. These guidelines addressed multiple aspects of the disease: epidemiology, diagnostic procedures, quality criteria and interpretation of chest CT scans, lung biopsy indication and procedures, etiological workup, methods and indications for family screening and genetic testing, assessment of the functional impairment and prognosis, indication and use of antifibrotic agents, lung transplantation, management of symptoms, comorbidities and complications, treatment of chronic respiratory failure, diagnosis and management of acute exacerbations of fibrosis.

CONCLUSION

These evidence-based guidelines are intended to guide the diagnosis and practical management of idiopathic pulmonary fibrosis.

Efficacy of Pirfenidone vs. Placebo in Unclassifiable Interstitial Lung Disease, by Surgical Lung Biopsy Status: Data From a post-hoc Analysis

Approximately 12–13% of patients with interstitial lung disease (ILD) are diagnosed with unclassifiable ILD (uILD), often despite thorough evaluation. A recent Phase 2 study (NCT03099187) described a significant effect of pirfenidone vs. placebo on forced vital capacity (FVC) measured by site spirometry in patients with progressive fibrosing uILD (hereafter referred to as the pirfenidone in uILD study). Here, we present the results from a post-hoc analysis of this study to assess patient baseline characteristics and the efficacy of pirfenidone vs. placebo analyzed by surgical lung biopsy (SLB) status. Mean FVC (mL) change over 24 weeks was included as a post-hoc efficacy outcome. Of 253 randomized patients, 88 (34.8%) had a SLB and 165 (65.2%) did not. Baseline characteristics were generally similar between SLB subgroups; however, patients who had a SLB were slightly younger and had a higher 6-min walk distance than those without a SLB. Mean FVC change over 24 weeks for pirfenidone vs. placebo was −90.9 vs. −146.3 mL, respectively, in patients who had a SLB, and 8.2 vs. −85.3 mL, respectively, in patients without a SLB. Overall, the results from the post-hoc analysis identified that pirfenidone may be an effective treatment in progressive fibrosing uILD over 24 weeks, irrespective of SLB status; however, caution should be taken when interpreting these data due to several limitations. There are differences in the treatment effect of pirfenidone between the subgroups that require further pathological and radiological investigation. In this manuscript, we also descriptively compared baseline characteristics from the overall pirfenidone in uILD study population with other uILD populations reported in the literature, with the aim of understanding if there are any similarities or differences within these cohorts. Most baseline characteristics for patients in the pirfenidone in uILD study were within the ranges reported in the literature; however, ranges were wide, highlighting the heterogeneity of uILD populations.

[French practical guidelines for the diagnosis and management of IPF - 2021 update, short version]

BACKGROUND

Since the previous French guidelines were published in 2017, substantial additional knowledge about idiopathic pulmonary fibrosis has accumulated.

METHODS

Under the auspices of the French-speaking Learned Society of Pulmonology and at the initiative of the coordinating reference center, practical guidelines for treatment of rare pulmonary diseases have been established. They were elaborated by groups of writers, reviewers and coordinators with the help of the OrphaLung network, as well as pulmonologists with varying practice modalities, radiologists, pathologists, a general practitioner, a head nurse, and a patients' association. The method was developed according to rules entitled "Good clinical practice" in the overall framework of the "Guidelines for clinical practice" of the official French health authority (HAS), taking into account the results of an online vote using a Likert scale.

RESULTS

After analysis of the literature, 54 recommendations were formulated, improved, and validated by the working groups. The recommendations covered a wide-ranging aspects of the disease and its treatment: epidemiology, diagnostic modalities, quality criteria and interpretation of chest CT, indication and modalities of lung biopsy, etiologic workup, approach to familial disease entailing indications and modalities of genetic testing, evaluation of possible functional impairments and prognosis, indications for and use of antifibrotic therapy, lung transplantation, symptom management, comorbidities and complications, treatment of chronic respiratory failure, diagnosis and management of acute exacerbations of fibrosis.

CONCLUSION

These evidence-based guidelines are aimed at guiding the diagnosis and the management in clinical practice of idiopathic pulmonary fibrosis.

Challenges in the Diagnosis and Management of Patients with Fibrosing Interstitial Lung Disease

Interstitial lung diseases (ILDs) are heterogeneous in their clinical presentation. Making a differential diagnosis of ILD requires a thorough medical history, clinical examination, serologies, high-resolution computed tomography (CT) scan, and, in some cases, bronchoalveolar lavage or surgical lung biopsy. Multidisciplinary discussion is recommended to improve diagnostic confidence. ILDs have a variable and unpredictable clinical course. Patients should be closely monitored to ensure that progression of ILD is detected promptly. This involves regular assessment of symptoms, lung function, and, where appropriate, high-resolution CT. Patients with some fibrosing ILDs may respond well to immunosuppressants, but even patients who respond well to immunosuppressants initially may later show deterioration despite appropriate management. The tyrosine kinase inhibitor nintedanib has been approved for the treatment of idiopathic pulmonary fibrosis, other chronic fibrosing ILDs with a progressive phenotype, and systemic sclerosis-associated ILD. The three case studies described in this article illustrate the challenges in the diagnosis and management of patients with fibrosing ILDs and the importance of taking a multidisciplinary and individualized approach to care, including regular monitoring and consideration of whether a patient's drug regimen needs to be changed when there is evidence of disease progression.

Pirfenidone in Unclassifiable Interstitial Lung Disease: A Subgroup Analysis by Concomitant Mycophenolate Mofetil and/or Previous Corticosteroid Use

Introduction

There are currently no approved treatments solely for unclassifiable interstitial lung disease (uILD); however, a recent trial showed this population can benefit from pirfenidone. We report a subgroup analysis of this trial to assess the effects of immunomodulators (concomitant mycophenolate mofetil [MMF] and/or previous corticosteroids) with pirfenidone in patients with uILD.

Methods

This was a multicenter, international, double-blind, randomized, placebo-controlled phase II trial of patients with progressive fibrosing uILD (NCT03099187). Patients were randomized (1:1) to receive pirfenidone 2403 mg/day or placebo. This analysis assessed forced vital capacity (FVC) change from baseline measured using site spirometry (key secondary endpoint) and safety over 24 weeks by concomitant MMF use at randomization (pre-specified analysis) and/or previous corticosteroid use (post hoc analysis).

Results

Overall, 253 patients were randomized, including 45 (17.8%) patients (pirfenidone, n = 23; placebo, n = 22) receiving concomitant MMF with/without previous corticosteroids (MMF subgroup); 79 (31.2%) patients (pirfenidone, n = 44; placebo, n = 35) receiving previous corticosteroids without MMF (corticosteroids/no-MMF subgroup); and 129 (51.0%) patients (pirfenidone, n = 60; placebo, n = 69) not receiving concomitant MMF or previous corticosteroids (no-corticosteroids/no-MMF subgroup). At 24 weeks, difference in mean (95% confidence interval) FVC change from baseline between pirfenidone and placebo was − 55.4 mL (− 206.7, 96.0; P = 0.4645) in the MMF subgroup; 128.4 mL (− 6.4, 263.3; P = 0.0617) in the corticosteroids/no-MMF subgroup; and 115.5 mL (35.1, 195.9; P = 0.0052) in the no-corticosteroids/no-MMF subgroup. All subgroups generally exhibited a similar pattern of treatment-emergent adverse events.

Conclusion

Although limited by design and small sample sizes, this analysis suggests pirfenidone may be less effective in patients with uILD receiving concomitant MMF, whereas a beneficial treatment effect was observed in patients not receiving concomitant MMF regardless of previous corticosteroid use. Pirfenidone was well tolerated regardless of MMF and/or corticosteroid use.

Trial Registration Number

ClinicalTrials.gov: NCT03099187.

Fibroblast Activation Protein-Specific PET/CT Imaging in Fibrotic Interstitial Lung Diseases and Lung Cancer: A Translational Exploratory Study

Interstitial lung diseases (ILDs) comprise over 200 parenchymal lung disorders. Among them, fibrosing ILDs, especially idiopathic pulmonary fibrosis, are associated with a poor prognosis, whereas some other ILDs, such as sarcoidosis, have a much better prognosis. A high proportion manifests as fibrotic ILD (fILD). Lung cancer (LC) is a frequent complication of fILD. Activated fibroblasts are crucial for fibrotic processes in fILD. The aim of this exploratory study was to evaluate the imaging properties of static and dynamic fibroblast activation protein (FAP) inhibitor (FAPI) PET/CT in various types of fILD and to confirm FAP expression in fILD lesions by FAP immunohistochemistry of human fILD biopsy samples and of lung sections of genetically engineered (Nedd4-2-/- ) mice with an idiopathic pulmonary fibrosislike lung disease. Methods: PET scans of 15 patients with fILD and suspected LC were acquired 10, 60, and 180 min after the administration of 150-250 MBq of a 68Ga-labeled FAPI tracer (FAPI-46). In 3 patients, dynamic scans over 40 min were performed instead of imaging after 10 min. The SUVmax and SUVmean of fibrotic lesions and LC were measured and CT-density-corrected. Target-to-background ratios (TBRs) were calculated. PET imaging was correlated with CT-based fibrosis scores. Time-activity curves derived from dynamic imaging were analyzed. FAP immunohistochemistry of 4 human fILD biopsy samples and of fibrotic lungs of Nedd4-2-/- mice was performed. Results: fILD lesions as well as LC showed markedly elevated 68Ga-FAPI uptake (density-corrected SUVmax and SUVmean 60 min after injection: 11.12 ± 6.71 and 4.29 ± 1.61, respectively, for fILD lesions and 16.69 ± 9.35 and 6.44 ± 3.29, respectively, for LC) and high TBR (TBR of density-corrected SUVmax and SUVmean 60 min after injection: 2.30 ± 1.47 and 1.67 ± 0.79, respectively, for fILD and 3.90 ± 2.36 and 2.37 ± 1.14, respectively, for LC). SUVmax and SUVmean decreased over time, with a stable TBR for fILD and a trend toward an increasing TBR in LC. Dynamic imaging showed differing time-activity curves for fILD and LC. 68Ga-FAPI uptake showed a positive correlation with the CT-based fibrosis index. Immunohistochemistry of human biopsy samples and the lungs of Nedd4-2-/- mice showed a patchy expression of FAP in fibrotic lesions, preferentially in the transition zone to healthy lung parenchyma. Conclusion:68Ga-FAPI PET/CT imaging is a promising new imaging modality for fILD and LC. Its potential clinical value for monitoring and therapy evaluation of fILD should be investigated in future studies.

Epidemiology of interstitial lung disease in patients with metastatic breast cancer at baseline and after treatment with HER2-directed therapy: a real-world data analysis

PURPOSE

Using real-world data, interstitial lung disease (ILD) prevalence before and after HER2-directed therapy was estimated. Potential ILD risk factors in patients receiving HER2-directed therapy for metastatic breast cancer (mBC) were evaluated.

METHODS

Adults with HER2-directed therapy for mBC initiated between September 25, 1998, and February 22, 2020 were, included. ILD was defined broadly as one or more of 64 lung conditions. Patients were followed until incident ILD, death, last contact, or study end.

RESULTS

In total, 533 patients were identified with median age at mBC of 57, 51% had de novo mBC, 43% were ever smokers, 30% had lung metastases, 9% had thoracic radiation, 6% had chronic obstructive pulmonary disease, and 16% had prevalent ILD. ILD cumulative incidence at one year was 9% (95% CI 6%, 12%), with a median follow-up of 23 months. Smoking (HR 2.2, 95% CI 1.1, 4.8) and Black/African-American race (HR 3.4, 95% CI 1.6, 7.5) were significantly associated with ILD; HRs for preexisting lung conditions (HR 1.8, 95% CI 0.9, 3.8) and thoracic radiation (HR 2.3, 95% CI 0.8, 7.1) were not statistically significant. Prevalent ILD was associated with 13-fold greater occurrence of incident ILD. 85% of patients with prevalent or incident ILD were symptomatic.

CONCLUSIONS

This real-world population of patients with mBC had a high prevalence of ILD prior to HER2-directed therapy, reflecting the multifactorial causation of interstitial lung changes. The cumulative incidence of ILD in patients receiving HER2-directed therapy for mBC augments prior reports. Symptomatic presentation suggests an opportunity for early intervention.

Radiological pleuroparenchymal fibroelastosis-like lesion in idiopathic interstitial pneumonias

Background

Pleuroparenchymal fibroelastosis (PPFE) is characterised by predominant upper lobe pleural and subpleural lung parenchymal fibrosis. Radiological PPFE-like lesion has been associated with various types of interstitial lung diseases. However, the prevalence and clinical significance of radiological PPFE-like lesion in patients with idiopathic interstitial pneumonias (IIPs) are not fully understood. We aimed to determine the prevalence and clinical impact on survival of radiological PPFE-like lesion in patients with IIPs.

Methods

A post-hoc analysis was conducted using data from the Japanese nationwide cloud-based database of patients with IIPs. All the patients in the database were diagnosed as having IIPs by multidisciplinary discussion. Patients diagnosed with idiopathic PPFE were excluded. Clinical data and chest computed tomography (CT) image of 419 patients with IIPs were analysed. The presence of radiological PPFE-like lesion was independently evaluated by two chest radiologists blind to the clinical data.

Results

Of the 419 patients with IIPs, radiological PPFE-like lesions were detected in 101 (24.1%) patients, mainly in idiopathic pulmonary fibrosis (IPF) and unclassifiable IIPs, but less in idiopathic nonspecific interstitial pneumonia. Prognostic analyses revealed that radiological PPFE-like lesion was significantly associated with poor outcome in patients with IIPs, which was independent of age, IPF diagnosis and %FVC. In survival analyses, the patients with radiological PPFE-like lesions had poor survival compared with those without (log-rank, p < 0.0001). Subgroup analyses demonstrated that radiological PPFE-like lesion was significantly associated with poor survival both in patients with IPF and those with unclassifiable IIPs.

Conclusion

Radiological PPFE-like lesion is a condition that could exist in IIPs, mainly in IPF and unclassifiable IIPs. Importantly, the radiological PPFE-like lesion is a non-invasive marker to predict poor outcome in patients with IIPs, which should be carefully considered in clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01892-9.

Progressive fibrosing interstitial lung disease: prevalence and clinical outcome

Background

The progressive fibrosing (PF) phenotype of interstitial lung disease (ILD) is characterised by worsening respiratory symptoms, lung function, and extent of fibrosis on high-resolution computed tomography. We aimed to investigate the prevalence and clinical outcomes of PF-ILD in a real-world cohort and assess the prognostic significance of the PF-ILD diagnostic criteria.

Methods

Clinical data of patients with fibrosing ILD other than idiopathic pulmonary fibrosis (IPF) consecutively diagnosed at a single centre were retrospectively reviewed. A PF phenotype was defined based on the criteria used in the INBUILD trial.

Results

The median follow-up duration was 62.7 months. Of the total of 396 patients, the mean age was 58.1 years, 39.9% were men, and rheumatoid arthritis-ILD was the most common (42.4%). A PF phenotype was identified in 135 patients (34.1%). The PF-ILD group showed lower forced vital capacity and total lung capacity (TLC) than the non-PF-ILD group. The PF-ILD group also showed poorer survival (median survival, 91.2 months vs. not reached; P < 0.001) than the non-PF-ILD group. In multivariable Cox analysis adjusted for age, DL_CO, HRCT pattern, and specific diagnosis, PF phenotype was independent prognostic factor (hazard ratio, 3.053; P < 0.001) in patients with fibrosing ILD. Each criterion of PF-ILD showed similar survival outcomes.

Conclusions

Our results showed that approximately 34% of patients with non-IPF fibrosing ILD showed a progressive phenotype and a poor outcome similar to that of IPF, regardless of the diagnostic criteria used.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01879-6.

Predictors of Mortality in Progressive Fibrosing Interstitial Lung Diseases

Background: Progressive fibrosing interstitial lung disease (PF-ILD) and idiopathic pulmonary fibrosis (IPF) share similar progression phenotype but with different pathophysiological mechanism. The purpose of this study was to assess clinical characteristics and outcomes of patients with PF-ILD in a single-center cohort. Methods: Patients with PF-ILD treated in Shanghai Pulmonary Hospital from Jan. 2013 to Dec. 2014 were retrospectively analyzed. Baseline characteristics and clinical outcomes were collected for survival analysis to identifying clinical predictors of mortality. Results: Among 608 patients with ILD, 132 patients met the diagnostic criteria for PF-ILD. In this single-center cohort, there were 51 (38.6%) cases with connective tissue disease-associated interstitial lung disease (CTD-ILD) and 45 (34.1%) with unclassifiable ILDs. During follow-up, 83 patients (62.9%) either died (N = 79, 59.8%) or underwent lung transplantations (N = 4, 3.0%) with a median duration follow-up time of 53.7 months. Kaplan-Meier survival curves revealed that the 1, 3 and 5-years survival of PF-ILD were 90.9, 58.8 and 48.1%, respectively. In addition, the prognosis of patients with PF-ILD was similar to those with IPF, while it was worse than non-PF-ILD ones. Multivariate Cox regression analysis demonstrated that high-resolution computed tomography (HRCT) scores (HR 1.684, 95% CI 1.017-2.788, p = 0.043) and systolic pulmonary artery pressure (SPAP) > 36.5 mmHg (HR 3.619, 95%CI 1.170-11.194, p = 0.026) were independent risk factors for the mortality of PF-ILD. Conclusion: Extent of fibrotic changes on HRCT and pulmonary hypertension were predictors of mortality in patients with PF-ILD.

Prognostic impact of HNF4α expression in interstitial lung disease

Pneumocyte injury is a crucial factor influencing the severity of interstitial lung disease (ILD). In this study, we investigated the potential of hepatocyte nuclear factor α (HNF4α) as an immunohistochemical marker to detect pneumocyte injury and as a prognostic marker. Surgical lung biopsy specimens were collected from 309 patients with different types of ILDs (61 idiopathic pulmonary fibrosis (IPF), 173 non-IPF, and 75 unclassifiable ILD). HNF4α expression were examined and the frequency of positive cells (per mm² ) was calculated. HNF4α was strongly expressed in regenerating pneumocytes present on fibroblastic foci, Masson bodies/organizing alveoli. In the non-IPF and unclassifiable ILD groups, cases with high frequency expression showed significantly poorer outcome. Particularly, in the unclassifiable ILD group, the prognostic impact was more significant (death due to ILD, log-rank test, p < 0.0001), with a 10-year survival rate (hazard ratio 11.1, Wald test, p = 0.0003), as compared to the non-IPF group (log-rank test, p = 0.0269; hazard ratio 2.7, Wald test, p = 0.0334). Multivariable analysis focusing on the unclassifiable ILD group confirmed that the frequent HNF4α expression was an independent prognostic factor (hazard ratio 28.6; Wald test, p = 0.0033). Thus, HNF4α can be utilized as an immunohistochemical marker for pneumocyte injury and have prognostic impact particularly in unclassifiable ILD.

From pulmonary fibrosis to progressive pulmonary fibrosis: a lethal pathobiological jump

The month of September is Pulmonary Fibrosis Awareness Month. In this context, we would like to highlight the concept of progressive pulmonary fibrosis, a common denominator/phenotype of many interstitial lung diseases other than idiopathic pulmonary fibrosis, leading to clinical deterioration, decreased quality of life, and high mortality.

Diagnosis and Management of Fibrotic Interstitial Lung Diseases

Nonidiopathic pulmonary fibrosis (non-IPF) progressive fibrotic interstitial lung diseases (PF-ILDs) are a heterogeneous group of ILDs, often challenging to diagnose, although an accurate diagnosis has significant implications for both treatment and prognosis. A subgroup of these patients experiences progressive deterioration in lung function, physical performance, and quality of life after conventional therapy. Risk factors for ILD progression include older age, lower baseline pulmonary function, and a usual interstitial pneumonia pattern. Management of non-IPF P-ILD is both pharmacologic and nonpharmacologic. Antifibrotic drugs, originally approved for IPF, have been considered in patients with other fibrotic ILD subtypes, with favorable results in clinical trials.

Interstitial Lung Disease in 2020: A History of Progress

Interstitial lung diseases (ILDs) are heterogenous and complex chronic lung diseases that even today are challenging to diagnose and classify. The terminology and mechanistic understanding of specific ILDs have evolved substantially over the last centuries and decades, and clinicians, pathologists, radiologists, and researchers are continuously working to untangle the various ILDs of differing causes. Despite many drawbacks and negative clinical trials, the unremitting work of ILD researchers have resulted in great therapeutic successes over the last decade. In this chapter, the authors present historical aspects of ILD and build a foundation to understand current and emerging concepts in ILD.

Prevalence and Incidence of Chronic Fibrosing Interstitial Lung Diseases with a Progressive Phenotype in the United States Estimated in a Large Claims Database Analysis

INTRODUCTION

Many fibrosing interstitial lung diseases (ILDs) develop a chronic progressive phenotype. While idiopathic pulmonary fibrosis, which is always progressive, is well characterized with established treatment options, the epidemiology of other chronic fibrosing ILDs with a progressive phenotype has not been widely investigated. Treatment options are limited, with a high unmet need. This claims database study estimates the incidence and prevalence of these diseases in the USA.

METHODS

Diagnosis, procedure and resource utilization codes from insurance claims were used to identify patients with fibrosing ILD and those with a chronic progressive phenotype among 37,565,644 adult patients in the IBM® MarketScan® Research Database 2012-2015. Two eligible ILD claims were required for a fibrosing ILD diagnosis. Progression was defined using a novel algorithm constituted by criteria considered proxies for progression. Patients were defined as having incident (new) or existing diagnoses based on claims during a 365-day period before study entry.

RESULTS

The estimated age- and sex-adjusted prevalence per 100,000 persons of fibrosing ILD (95% confidence interval) was 117.82 (116.56, 119.08) and of chronic fibrosing ILDs with a progressive phenotype was 70.30 (69.32, 71.27). The estimated adjusted incidence per 100,000 patient-years of fibrosing ILD was 51.56 (50.88, 52.24) and of chronic fibrosing ILDs with a progressive phenotype was 32.55 (32.01, 33.09). Among incident fibrosing ILD patients, 57.3% experienced progression over a median of 117 days (interquartile range 63-224), with largely comparable rates of progression among different diseases.

CONCLUSIONS

Chronic fibrosing ILDs with a progressive phenotype comprise a relatively new disease construct requiring varied approaches to obtain reliable estimates of prevalence and incidence. This is the first large claims database study using real-world data to provide estimates of the prevalence and incidence of these diseases among a very large segment of the US population and could form the groundwork for future studies.

Unclassifiable, or simply unclassified interstitial lung disease?

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

A contemporary practical approach to the multidisciplinary management of unclassifiable interstitial lung disease

Fibrotic interstitial lung diseases (ILDs) frequently have nonspecific and overlapping clinical and radiological features, resulting in approximately 10-20% of patients with ILD lacking a clear diagnosis and thus being labelled with unclassifiable ILD. The objective of this review is to describe how patients with unclassifiable ILD should be evaluated and what impact specific clinical, radiological, and histopathological features may have on management decisions, focusing on patients with a predominantly fibrotic phenotype. We highlight recent data that have suggested an increasing role for antifibrotic medications in a variety of fibrotic ILDs, but justify the ongoing importance of making an accurate ILD diagnosis given the benefit of immunomodulatory therapies in many patient populations. We provide a practical approach to support management decisions that can be used by clinicians and tested by clinical researchers, and further identify the need for additional research to support a rational and standardised approach to the management of patients with unclassifiable ILD.

Acute exacerbation of unclassifiable idiopathic interstitial pneumonia: comparison with idiopathic pulmonary fibrosis

Background:

Acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) is well known as a life-threatening condition during its clinical course. However, the clinical features and prognosis in AE of unclassifiable idiopathic interstitial pneumonia (AE-UCIIP) remain to be elucidated. The aim of this study was to clarify the clinical features and prognosis of AE-UCIIP compared with those of AE-IPF.

Methods:

In 187 patients with UCIIP or IPF, 64 patients with AE-UCIIP or AE-IPF, who were diagnosed and treated at our hospital, were retrospectively evaluated.

Results:

A total of 24 patients with AE-UCIIP were significantly older (p = 0.011), included more women (p < 0.001) and never-smokers (p < 0.001), and showed fewer lung lesions on high-resolution computed tomography (p = 0.006) than 40 patients with AE-IPF. Incidence of AE-UCIIP was 10.29%/year and was significantly higher than in AE-IPF (Gray’s test, p = 0.008). Prognosis of AE-UCIIP was as poor as that of AE-IPF (log-rank, p = 0.681). Percent-predicted forced vital capacity (%FVC) [hazard ratio (HR) 0.934, p = 0.045], and GAP stage within 12 months before AE (HR 3.530, p = 0.023), and partial pressure arterial oxygen/fraction of inspired oxygen (PaO₂/FiO₂) ratio at AE (HR 0.998, p = 0.016) were significant prognostic factors. Finally, commencement of long-duration (⩾12 h) direct hemoperfusion with a polymyxin B-immobilised fibre column (PMX-DHP) within 2 days after admission significantly improved survival (log-rank, p = 0.038) and was a significant prognostic factor (HR 0.175, p = 0.0039) in AE-UCIIP. Long-duration PMX-DHP showed favourable treatment effects even in the combined group of patients with AE-UCIIP or AE-IPF (log-rank p = 0.002; HR 0.328, p = 0.006).

Conclusions:

Patients with AE-UCIIP were older and included more women and never-smokers than those with AE-IPF. Prognosis of AE-UCIIP was as poor as that of AE-IPF.

The reviews of this paper are available via the supplemental material section.

Progression in the Management of Non-Idiopathic Pulmonary Fibrosis Interstitial Lung Diseases, Where Are We Now and Where We Would Like to Be

A significant proportion of patients with interstitial lung disease (ILD) may develop a progressive fibrosing phenotype characterized by worsening of symptoms and pulmonary function, progressive fibrosis on chest computed tomography and increased mortality. The clinical course in these patients mimics the relentless progressiveness of idiopathic pulmonary fibrosis (IPF). Common pathophysiological mechanisms such as a shared genetic susceptibility and a common downstream pathway—self-sustaining fibroproliferation—support the concept of a progressive fibrosing phenotype, which is applicable to a broad range of non-IPF ILDs. While antifibrotic drugs became the standard of care in IPF, immunosuppressive agents are still the mainstay of treatment in non-IPF fibrosing ILD (F-ILD). However, recently, randomized placebo-controlled trials have demonstrated the efficacy and safety of antifibrotic treatment in systemic sclerosis-associated F-ILD and a broad range of F-ILDs with a progressive phenotype. This review summarizes the current pharmacological management and highlights the unmet needs in patients with non-IPF ILD.

Utility of a Molecular Classifier as a Complement to High-Resolution Computed Tomography to Identify Usual Interstitial Pneumonia

Rationale: Usual interstitial pneumonia (UIP) is the defining morphology of idiopathic pulmonary fibrosis (IPF). Guidelines for IPF diagnosis conditionally recommend surgical lung biopsy for histopathology diagnosis of UIP when radiology and clinical context are not definitive. A "molecular diagnosis of UIP" in transbronchial lung biopsy, the Envisia Genomic Classifier, accurately predicted histopathologic UIP.Objectives: We evaluated the combined accuracy of the Envisia Genomic Classifier and local radiology in the detection of UIP pattern.Methods: Ninety-six patients who had diagnostic lung pathology as well as a transbronchial lung biopsy for molecular testing with Envisia Genomic Classifier were included in this analysis. The classifier results were scored against reference pathology. UIP identified on high-resolution computed tomography (HRCT) as documented by features in local radiologists' reports was compared with histopathology.Measurements and Main Results: In 96 patients, the Envisia Classifier achieved a specificity of 92.1% (confidence interval [CI],78.6-98.3%) and a sensitivity of 60.3% (CI, 46.6-73.0%) for histology-proven UIP pattern. Local radiologists identified UIP in 18 of 53 patients with UIP histopathology, with a sensitivity of 34.0% (CI, 21.5-48.3%) and a specificity of 96.9% (CI, 83.8-100%). In conjunction with HRCT patterns of UIP, the Envisia Classifier results identified 24 additional patients with UIP (sensitivity 79.2%; specificity 90.6%).Conclusions: In 96 patients with suspected interstitial lung disease, the Envisia Genomic Classifier identified UIP regardless of HRCT pattern. These results suggest that recognition of a UIP pattern by the Envisia Genomic Classifier combined with HRCT and clinical factors in a multidisciplinary discussion may assist clinicians in making an interstitial lung disease (especially IPF) diagnosis without the need for a surgical lung biopsy.

Current monitoring and treatment of progressive fibrosing interstitial lung disease: a survey of physicians in Japan, the United States, and the European Union

OBJECTIVE

To understand assumptions about and approaches to interstitial lung disease (ILD), including those of the progressive phenotype (progressive fibrosing ILD), this multinational survey assessed physicians' attitudes toward, knowledge of, and management strategies for progressive fibrosing ILD.

METHODS

This internet-based survey of physicians was conducted between November 2018 and February 2019. Practical management strategies for progressive fibrosing ILD, and current approaches to the assessment and treatment of ILD, were compared between countries/regions (Japan vs. United States and European Union) and specialties (pulmonologists vs. rheumatologists).

RESULTS

The survey was completed by 574 respondents. Compared with Western countries, the progressive fibrosing phenotype concept was not widely understood by Japanese respondents, with no notable differences in the understanding of this phenotype between pulmonologists and rheumatologists. Across all regions, pulmonary function tests, diffusing capacity of the lungs for carbon monoxide assessments, and pulse oximeter measurements were commonly performed at intervals of ≤6 months. In general, physicians in the United States and European Union preferred physiologic approaches for follow-up, while those in Japan preferred imaging and blood monitoring. Compared with rheumatologists, pulmonologists performed more frequent monitoring of autoimmune ILDs, and the differences between specialties were most pronounced in Japan. Regional differences in treatment approaches were observed, probably reflecting the local availability of agents and healthcare environments.

CONCLUSIONS

Awareness and management of progressive fibrosing ILD varied between specialties and regions, highlighting an unmet need for standardized diagnosis, treatment guidelines, and specialist education in this area.

Diagnostic and Therapeutic Applications of Extracellular Vesicles in Interstitial Lung Diseases

Interstitial lung diseases (ILDs) are chronic irreversible pulmonary conditions with significant morbidity and mortality. Diagnostic approaches to ILDs are complex and multifactorial. Effective therapeutic interventions are continuously investigated and explored with substantial progress, thanks to advances in basic understanding and translational efforts. Extracellular vesicles (EVs) offer a new paradigm in diagnosis and treatment. This leads to two significant implications: new disease biomarker discovery that enables reliable diagnosis and disease assessment and the development of regenerative medicine therapeutics that target fibroproliferative processes in diseased lung tissue. In this review, we discuss the current understanding of the role of diseased tissue-derived EVs in the development of interstitial lung diseases, the utility of these EVs as diagnostic and prognostic tools, and the existing therapeutic utility of EVs. Furthermore, we review the potential therapeutic application of EVs derived from various cellular sources.

Clinical and Functional Characteristics of Patients with Unclassifiable Interstitial Lung Disease (uILD): Long-Term Follow-Up Data from European IPF Registry (eurIPFreg)

(1) Aim of the study: In spite of extensive research, up to 20% of interstitial lung diseases (ILD) patients cannot be safely classified. We analyzed clinical features, progression factors, and outcomes of unclassifiable ILD (uILD). (2) Methods: A total of 140 uILD subjects from the University of Giessen and Marburg Lung Center (UGMLC) were recruited between 11/2009 and 01/2019 into the European Registry for idiopathic pulmonary fibrosis (eurIPFreg) and followed until 01/2020. The diagnosis of uILD was applied only when a conclusive diagnosis could not be reached with certainty. (3) Results: In 46.4% of the patients, the uILD diagnosis was due to conflicting clinical, radiological, and pathological data. By applying the diagnostic criteria of usual interstitial pneumonia (UIP) based on computed tomography (CT), published by the Fleischner Society, 22.2% of the patients displayed a typical UIP pattern. We also showed that forced vital capacity (FVC) at baseline (p = 0.008), annual FVC decline ≥10% (p < 0.0001), smoking (p = 0.033), and a diffusing capacity of the lung for carbon monoxide (DLco) ≤55% of predicted value at baseline (p < 0.0001) were significantly associated with progressive disease. (4) Conclusions: The most important prognostic factors in uILD are baseline level and decline in lung function and smoking. The use of Fleischner diagnostic criteria allows further differentiation and accurate diagnosis.

The natural history of progressive fibrosing interstitial lung diseases

We used data from the INBUILD and INPULSIS trials to investigate the natural history of progressive fibrosing interstitial lung diseases (ILDs).

Subjects in the two INPULSIS trials had a clinical diagnosis of idiopathic pulmonary fibrosis (IPF) while subjects in the INBUILD trial had a progressive fibrosing ILD other than IPF and met protocol-defined criteria for ILD progression despite management. Using data from the placebo groups, we compared the rate of decline in forced vital capacity (FVC) (mL·year⁻¹) and mortality over 52 weeks in the INBUILD trial with pooled data from the INPULSIS trials.

The adjusted mean annual rate of decline in FVC in the INBUILD trial (n=331) was similar to that observed in the INPULSIS trials (n=423) (−192.9 mL·year⁻¹ and −221.0 mL·year⁻¹, respectively; nominal p-value=0.19). The proportion of subjects who had a relative decline in FVC >10% predicted at Week 52 was 48.9% in the INBUILD trial and 48.7% in the INPULSIS trials, and the proportion who died over 52 weeks was 5.1% in the INBUILD trial and 7.8% in the INPULSIS trials. A relative decline in FVC >10% predicted was associated with an increased risk of death in the INBUILD trial (hazard ratio 3.64) and the INPULSIS trials (hazard ratio 3.95).

These findings indicate that patients with fibrosing ILDs other than IPF, who are progressing despite management, have a subsequent clinical course similar to patients with untreated IPF, with a high risk of further ILD progression and early mortality.

Analyses of data from the INBUILD and INPULSIS trials suggest that progressive fibrosing ILDs other than IPF have a clinical course similar to IPF, irrespective of underlying ILD diagnosis or the fibrotic pattern on HRCThttp://bit.ly/3apG0Q5

The extended utility of antifibrotic therapy in progressive fibrosing interstitial lung disease

INTRODUCTION

The approval of two antifibrotic treatment agents for delaying disease progression in idiopathic pulmonary fibrosis (IPF), has prompted researchers to look at expanding the role of antifibrotic therapy to other fibrosing interstitial lung disease (ILD). Similarities in the pathological mechanisms that lead to the development of IPF have been implicated in other progressive fibrosing ILD (PF-ILD) such as chronic hypersensitivity pneumonitis, connective tissues disease associated ILD, sarcoidosis, occupational ILD and idiopathic non-specific interstitial pneumonia (iNSIP). This has prompted the rationale to use antifibrotic therapy to target similar molecular pathways in these diseases.

AREAS COVERED

This review will summarise the available evidence from randomised controlled trials that have evaluated the use of antifibrotic therapy in PF-ILD outside the realm of IPF.

EXPERT OPINION

There is promising data for antifibrotic therapy as a therapeutic option for non IPF PF-ILD. The new therapy option does provide some challenges that need to be addressed such as timing of initiation of therapy, clarifying the strategy for overlap or combination with existing immunosuppressive therapies and potential drug interactions. There is an unmet need to determine accurate predictors of disease progression to allow early intervention for the preservation of lung function and mortality reduction.

Diagnostic approach of fibrosing interstitial lung diseases of unknown origin

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

Prognosis and causes of death of patients with acute exacerbation of fibrosing interstitial lung diseases

BACKGROUND

The aim of this study was to compare the clinical characteristics, causes of death and factors impacting on the prognosis of patients with idiopathic pulmonary fibrosis (IPF) and other fibrosing interstitial lung disease (FILD) with a history of acute exacerbation (AE) of IPF or FILD.

METHODS

Retrospective data of hospital treatment periods caused by AE-IPF and AE-FILD were collected from medical records. Clinical features and survival data of IPF and non-IPF cases were evaluated and compared. The underlying and immediate causes of death were gathered from death certificates.

RESULTS

A total of 128 patients fulfilled the criteria for inclusion. IPF (n=79/62%), rheumatoid arthritis-associated interstitial lung disease (RA-ILD; n=17/14%) and asbestosis (n=11/8.6%) were the most common FILD subgroups in the study. The median survival after hospitalisation in AE-IPF was 2.6 months compared with 21 months in other AE-FILDs (p<0.001). The survival difference was not explained by age, gender or pulmonary function test results at the time of hospitalisation. Patients with non-specific interstitial pneumonia and RA-ILD had the most favourable prognosis. ILD was the most common underlying cause of death in both patients with IPF and with other FILD accounting for 87% and 78% of deaths, respectively.

CONCLUSIONS

We detected a significantly longer survival in AE of patients with non-IPF compared with that of AE-IPFs. The prognosis of patients was affected by the underlying lung disease since pulmonary fibrosis was the underlying cause of death in the majority of all patients with FILD having experienced an AE.

Pathologic separation of idiopathic pulmonary fibrosis from fibrotic hypersensitivity pneumonitis

Accurate separation of idiopathic pulmonary fibrosis from fibrotic (chronic) hypersensitivity pneumonitis is crucial to patient management, but is frequently a difficult problem. Our objective was to identify pathologic variables that help make this separation. Clinical, radiological, and pathologic data were re-reviewed for 23 patients with a fibrotic interstitial lung disease and biopsy suggesting idiopathic pulmonary fibrosis or fibrotic hypersensitivity pneumonitis. Clinical features, high-resolution computed tomography, and surgical lung biopsies were each examined independently using a prespecified approach. This was followed by a multidisciplinary discussion in which the likelihood of an idiopathic pulmonary fibrosis diagnosis was assigned by the clinician alone based only on clinical data, by the clinician and radiologist based on integrated clinical and radiologic data, and by the clinician, radiologist, and pathologist based on all three domains. A higher multidisciplinary discussion-based confidence of idiopathic pulmonary fibrosis was associated with older age at diagnosis, male sex, higher forced vital capacity, and absence of ground glass changes. Pathologic variables associated with a higher multidisciplinary discussion-based confidence of idiopathic pulmonary fibrosis included increased number of fibroblast foci/cm² and increased subpleural fibrosis. Pathologic variables associated with a higher multidisciplinary discussion-based confidence of hypersensitivity pneumonitis included an increased fraction of bronchioles with peribronchiolar metaplasia, increased foci of peribronchiolar metaplasia/cm², and presence of giant cells/granulomas. These results provide guidance in separating idiopathic pulmonary fibrosis from hypersensitivity pneumonitis; however, a third of cases could not be confidently classified even when using these pathologic features combined with clinical and radiologic information in a multidisciplinary discussion.