Management of Connective Tissue Disease-related Interstitial Lung Disease

The clinical value of KL-6 for predicting the occurrence and severity of connective tissue disease-associated interstitial lung disease is not affected by CTD type or treatment

Objective

The aim of this study was to explore the potential values of Krebs von den Lungen-6 (KL-6), neutrophil to lymphocyte ratio (NLR), systemic immune inflammation (SII), platelet to lymphocyte ratio (PLR), monocyte to lymphocyte ratio (MLR) and red blood cell distribution width (RDW) in the diagnosis and evaluation of the severity of connective tissue disease-associated interstitial lung disease (CTD-ILD).

Methods

A total of 140 connective tissue disease (CTD) patients and 85 CTD-ILD patients were recruited for this study at Shanxi Provincial People's Hospital from May 2022 to May 2023. Patients were divided into subgroups based on medication history and CTD subtypes to compare and analyze the clinical data and laboratory parameters of CTD-ILD patients and CTD patients. The receiver operating characteristic curve (ROC) was used to evaluate the diagnostic efficacy of KL-6, NLR, SII, PLR, MLR, and RDW in identifying CTD-ILD patients from CTD patients. A Spearman correlation analysis was conducted to elucidate the correlations between these markers and the lung function parameters of forced vital capacity (FVC, %), forced expired volume in one second (FEV1, %), and diffusing capacity of carbon monoxide (DLCO, %). Finally, binary logistic regression analysis was applied to discern the independent risk factors for CTD-ILD.

Results

NLR, SII, MLR, RDW, and KL-6 displayed significant statistical differences in the experimental groups. In both untreated and treated subgroups, KL-6 displayed higher values for CTD-ILD than CTD among all CTD subtypes. In untreated subgroups, there were significant differences in MLR levels between rheumatoid arthritis (RA) and RA-ILD patients and in NLR levels between Sjögren syndrome (SjS) and SjS-ILD patients. There were also significant differences in RDW-SD between the "other CTD" and "other CTD-ILD" groups. In treated subgroups, there were significant differences in both RDW-SD and RDW-CV between RA and RA-ILD patients and in NLR, SII, MLR, PLR, and RDW-SD between "other CTD" and "other CTD-ILD" groups. ROC revealed that KL-6 emerged as the most effective predictor for CTD-ILD in both treated and untreated groups. The multivariate logistic regression analysis results showed that both KL-6 and age were independent risk factors for CTD-ILD. NLR, SII, and PLR were negatively correlated with DLCO (%) in the untreated CTD-ILD group, and KL-6 was negatively correlated with various lung function parameters in both treated and untreated CTD-ILD groups.

Conclusion

KL-6 emerged as the most promising biomarker for diagnosing CTD-ILD and assessing its severity. The diagnostic value of KL-6 was unaffected by medication interference and surpassed the value of other parameters, such as NLR, SII, MLR, and RDW. The diagnostic value of RDW-SD was higher than that of RDW-CV in CTD-ILD patients. NLR, SII, MLR, and PLR have potential value in diagnosing the different types of CTD-ILD.

Novel Therapeutic Approaches in Connective Tissue Disease-Associated Interstitial Lung Disease

Connective tissue diseases (CTD) comprise a group of autoimmune diseases that can affect multiple organs in the body including the lungs. The most common form of pulmonary involvement is interstitial lung disease (ILD). CTD-associated ILD (CTD-ILD) can take one of several courses including nonprogressive, chronically progressive, or rapidly progressive. Chronically and rapidly progressive patterns are associated with increased mortality. Limited randomized controlled trial data are available for treatment of CTD-ILD, with most data coming from systemic sclerosis-related ILD. The current first-line treatment for all CTD-ILD is immunosuppression with consideration of antifibrotics, stem cell transplant, and lung transplant in progressive disease. In this article, we review data for ILD treatment options in systemic sclerosis, rheumatoid arthritis, myositis, and primary Sjögren's syndrome-related ILDs.

Role of serum B-cell-activating factor and interleukin-17 as biomarkers in the classification of interstitial pneumonia with autoimmune features

Interstitial pneumonia with autoimmune features (IPAF) is a type of interstitial lung disease (ILD) with immune features that do not meet the diagnostic criteria for specific connective tissue diseases (CTDs). This retrospective case-control study investigated the role of serum B-cell-activating factor of the tumor necrosis factor family (BAFF) and interleukin (IL)-17 as biomarkers for IPAF. The differences in serum BAFF, IL-17, and IL-10 were compared among patients with idiopathic pulmonary fibrosis (IPF), IPAF, ILD associated with CTD (CTD-ILD), and healthy controls. The patients were treatment naïve. The correlations of BAFF with IL-10, IL-17, and pulmonary function were analyzed. The classifiable value of BAFF for IPAF was examined. The results showed that the serum levels of BAFF and IL-17 in the IPAF and CTD-ILD groups were higher than in the IPF group. High BAFF levels and high predicted diffusion capacity of the lungs for carbon monoxide (DLCO) were independent predictive factors for IPAF vs IPF. In the IPAF and CTD-ILD groups, serum BAFF levels were negatively correlated with predicted values of forced vital capacity (FVC%) and diffusing capacity of the lungs for carbon monoxide (DLCO%) and positively correlated with serum IL-17 and IL-10 levels. The cutoff value of combined BAFF and IL-17 was 0.704, and the sensitivity and specificity for classifying IPAF were 78.9 and 95.7%, respectively. In conclusion, combining serum BAFF and IL-17 as a biomarker may have classifiable value in differentiating IPAF from other forms of ILD.

Thin-Section CT in the Categorization and Management of Pulmonary Fibrosis including Recently Defined Progressive Pulmonary Fibrosis

While idiopathic pulmonary fibrosis (IPF) is the most common type of fibrotic lung disease, there are numerous other causes of pulmonary fibrosis that are often characterized by lung injury and inflammation. Although often gradually progressive and responsive to immune modulation, some cases may progress rapidly with reduced survival rates (similar to IPF) and with imaging features that overlap with IPF, including usual interstitial pneumonia (UIP)-pattern disease characterized by peripheral and basilar predominant reticulation, honeycombing, and traction bronchiectasis or bronchiolectasis. Recently, the term progressive pulmonary fibrosis has been used to describe non-IPF lung disease that over the course of a year demonstrates clinical, physiologic, and/or radiologic progression and may be treated with antifibrotic therapy. As such, appropriate categorization of the patient with fibrosis has implications for therapy and prognosis and may be facilitated by considering the following categories: (a) radiologic UIP pattern and IPF diagnosis, (b) radiologic UIP pattern and non-IPF diagnosis, and (c) radiologic non-UIP pattern and non-IPF diagnosis. By noting increasing fibrosis, the radiologist contributes to the selection of patients in which therapy with antifibrotics can improve survival. As the radiologist may be first to identify developing fibrosis and overall progression, this article reviews imaging features of pulmonary fibrosis and their significance in non-IPF-pattern fibrosis, progressive pulmonary fibrosis, and implications for therapy. Keywords: Idiopathic Pulmonary Fibrosis, Progressive Pulmonary Fibrosis, Thin-Section CT, Usual Interstitial Pneumonia © RSNA, 2024.

Biomarkers in the Pathogenesis, Diagnosis, and Treatment of Systemic Sclerosis

Systemic sclerosis (SSc) is a complex autoimmune disease characterized by vascular damage, vasoinstability, and decreased perfusion with ischemia, inflammation, and exuberant fibrosis of the skin and internal organs. Biomarkers are analytic indicators of the biological and disease processes within an individual that can be accurately and reproducibly measured. The field of biomarkers in SSc is complex as recent studies have implicated at least 240 pathways and dysregulated proteins in SSc pathogenesis. Anti-nuclear antibodies (ANA) are classical biomarkers with well-described clinical classifications and are present in more than 90% of SSc patients and include anti-centromere, anti-Th/To, anti-RNA polymerase III, and anti-topoisomerase I antibodies. Transforming growth factor-β (TGF-β) is central to the fibrotic process of SSc and is intimately intertwined with other biomarkers. Tyrosine kinases, interferon-1 signaling, IL-6 signaling, endogenous thrombin, peroxisome proliferator-activated receptors (PPARs), lysophosphatidic acid receptors, and amino acid metabolites are new biomarkers with the potential for developing new therapeutic agents. Other biomarkers implicated in SSc-ILD include signal transducer and activator of transcription 4 (STAT4), CD226 (DNAX accessory molecule 1), interferon regulatory factor 5 (IRF5), interleukin-1 receptor-associated kinase-1 (IRAK1), connective tissue growth factor (CTGF), pyrin domain containing 1 (NLRP1), T-cell surface glycoprotein zeta chain (CD3ζ) or CD247, the NLR family, SP-D (surfactant protein), KL-6, leucine-rich α2-glycoprotein-1 (LRG1), CCL19, genetic factors including DRB1 alleles, the interleukins (IL-1, IL-4, IL-6, IL-8, IL-10 IL-13, IL-16, IL-17, IL-18, IL-22, IL-32, and IL-35), the chemokines CCL (2,3,5,13,20,21,23), CXC (8,9,10,11,16), CX3CL1 (fractalkine), and GDF15. Adiponectin (an indicator of PPAR activation) and maresin 1 are reduced in SSc patients. A new trend has been the use of biomarker panels with combined complex multifactor analysis, machine learning, and artificial intelligence to determine disease activity and response to therapy. The present review is an update of the various biomarker molecules, pathways, and receptors involved in the pathology of SSc.

Biomarkers in Systemic Sclerosis: An Overview

Systemic sclerosis (SSc) is a complex autoimmune disease characterized by significant fibrosis of the skin and internal organs, with the main involvement of the lungs, kidneys, heart, esophagus, and intestines. SSc is also characterized by macro- and microvascular damage with reduced peripheral blood perfusion. Several studies have reported more than 240 pathways and numerous dysregulation proteins, giving insight into how the field of biomarkers in SSc is still extremely complex and evolving. Antinuclear antibodies (ANA) are present in more than 90% of SSc patients, and anti-centromere and anti-topoisomerase I antibodies are considered classic biomarkers with precise clinical features. Recent studies have reported that trans-forming growth factor β (TGF-β) plays a central role in the fibrotic process. In addition, interferon regulatory factor 5 (IRF5), interleukin receptor-associated kinase-1 (IRAK-1), connective tissue growth factor (CTGF), transducer and activator of transcription signal 4 (STAT4), pyrin-containing domain 1 (NLRP1), as well as genetic factors, including DRB1 alleles, are implicated in SSc damage. Several interleukins (e.g., IL-1, IL-6, IL-10, IL-17, IL-22, and IL-35) and chemokines (e.g., CCL 2, 5, 23, and CXC 9, 10, 16) are elevated in SSc. While adiponectin and maresin 1 are reduced in patients with SSc, biomarkers are important in research but will be increasingly so in the diagnosis and therapeutic approach to SSc. This review aims to present and highlight the various biomarker molecules, pathways, and receptors involved in the pathology of SSc.

The Role of Macrophages in Connective Tissue Disease-Associated Interstitial Lung Disease: Focusing on Molecular Mechanisms and Potential Treatment Strategies

Connective tissue disease-associated interstitial lung disease (CTD-ILD) is a severe manifestation of CTD that leads to significant morbidity and mortality. Clinically, ILD can occur in diverse CTDs. Pathologically, CTD-ILD is characterized by various histologic patterns, such as nonspecific interstitial pneumonia, organizing pneumonia, and usual interstitial pneumonia. Abnormal immune system responses have traditionally been instrumental in its pathophysiology, and various changes in immune cells have been described, especially in macrophages. This article first briefly overviews the epidemiology, clinical characteristics, impacts, and histopathologic changes associated with CTD-ILD. Next, it summarizes the roles of various signaling pathways in macrophages or products of macrophages in ILD, helped by insights gained from animal models. In the following sections, this review returns to studies of macrophages in CTD-ILD in humans for an overall picture of the current understanding. Finally, we direct attention to potential therapies targeting macrophages in CTD-ILD in investigation or in clinical trials, as well as the future directions regarding macrophages in the context of CTD-ILD. Although the field of macrophages in CTD-ILD is still in its infancy, several lines of evidence suggest the potential of this area.

Efficacy and Safety of Nintedanib in Patients with Connective Tissue Disease-Interstitial Lung Disease (CTD-ILD): A Real-World Single Center Experience

Connective Tissue Disease-Interstitial Lung Disease (CTD-ILD) is a severe and fatal manifestation of systemic autoimmune disorders. Therapies rely on immunomodulators but their efficacy in ILD progression remains uncertain. Nintedanib, an antifibrotic agent that slows pulmonary function decline, has been approved for CTD-ILD treatment. The aim of this study was to assess the effectiveness and safety of nintedanib in CTD-ILD patients in a real-world data setting. A single-center, retrospective, and descriptive analysis of CTD-ILD patients treated with nintedanib from June 2019 to November 2022 was performed. The assessment of nintedanib treatment's efficacy was judged solely on the evolution of pulmonary function tests (PFTs), which were evaluated before and after treatment. Twenty-one patients (67% females, median age 64 years (IQR = 9) with CTD-ILD (systemic sclerosis n = 9, rheumatoid arthritis n = 5, dermatomyositis n = 4, juvenile rheumatoid arthritis n = 1, undifferentiated CTD n = 1, interstitial pneumonia with autoimmune features n = 1), 18 of whom were on concomitant immunosuppressives, had a median follow-up period of 10 months (IQR = 5). PFTs before and after treatment did not significantly differ. The mean FVC% difference was +0.9 (sd = 7.6) and the mean DLco% difference was +3.4 (sd = 12.6), suggesting numerical improvement of PFTs. The average percentage change was -0.3% and +7.6% for FVC% and DLco%, respectively, indicating stabilization of lung function. Our real-world data across a broad spectrum of CTD-ILD suggest that nintedanib could be beneficial in combination with immunosuppressives in slowing the rate of lung function decline.

Assessing prognostic factors correlating with response to nintedanib for connective tissue disease-associated interstitial lung disease: A real-world single-center study

OBJECTIVE

For patients with connective tissue disease-associated interstitial lung disease (CTD-ILD), early medical intervention would be desirable. This study analyzed the real-world, single-center use of nintedanib for CTD-ILD patients.

METHODS

Patients with CTD who received nintedanib from January 2020 to July 2022 were enrolled. Medical records review and stratified analyses of the collected data were conducted.

RESULTS

Reduction in the percentage of predicted forced vital capacity (%FVC) was seen in the elderly group (>70 years; P = .210), males (P = .027), the late group who started nintedanib >80 months after confirmation of an ILD disease activity (P = .03), the severe %DLco (diffusing capacity for carbon monoxide as a percentage of predicted) group (<40%; P = .20), the group who had extensive pulmonary fibrosis at the beginning of nintedanib (pulmonary fibrosis score >35%), and the low-dose group (nintedanib 50-100 mg/d; P = .40). %FVC did not decrease by >5% in the young group (<55 years), the early group who started nintedanib within 10 months after confirmation of an ILD disease activity, and the group whose pulmonary fibrosis score at the beginning of nintedanib was <35%.

CONCLUSION

It is important to diagnose ILD early and start antifibrotic drugs with proper timing for cases in need. It is better to start nintedanib early, especially for patients at risk (>70 years old, male, <40% DLco, and >35% areas of pulmonary fibrosis).

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

Background

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

Methods

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

Results

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

Conclusion

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