Connective Tissue Disease-associated Interstitial Lung Disease Patients Research Articles

Machine Learning of Plasma Proteomics Classifies Diagnosis of Interstitial Lung Disease.

Rationale: Distinguishing connective tissue disease-associated interstitial lung disease (CTD-ILD) from idiopathic pulmonary fibrosis (IPF) can be clinically challenging. Objectives: To identify proteins that separate and classify patients with CTD-ILD and those with IPF. Methods: Four registries with 1,247 patients with IPF and 352 patients with CTD-ILD were included in analyses. Plasma samples were subjected to high-throughput proteomics assays. Protein features were prioritized using recursive feature elimination to construct a proteomic classifier. Multiple machine learning models, including support vector machine, LASSO (least absolute shrinkage and selection operator) regression, random forest, and imbalanced Random Forest, were trained and tested in independent cohorts. The validated models were used to classify each case iteratively in external datasets. Measurements and Main Results: A classifier with 37 proteins (proteomic classifier 37 [PC37]) was enriched in the biological process of bronchiole development and smooth muscle proliferation and immune responses. Four machine learning models used PC37 with sex and age score to generate continuous classification values. Receiver operating characteristic curve analyses of these scores demonstrated consistent areas under the curve of 0.85-0.90 in the test cohort and 0.94-0.96 in the single-sample dataset. Binary classification demonstrated 78.6-80.4% sensitivity and 76-84.4% specificity in the test cohort and 93.5-96.1% sensitivity and 69.5-77.6% specificity in the single-sample classification dataset. Composite analysis of all machine learning models confirmed 78.2% (194 of 248) accuracy in the test cohort and 82.9% (208 of 251) in the single-sample classification dataset. Conclusions: Multiple machine learning models trained with large cohort proteomic datasets consistently distinguished CTD-ILD from IPF. Many of the identified proteins are involved in immune pathways. We further developed a novel approach for single-sample classification, which could facilitate honing the differential diagnosis of ILD in challenging cases and improve clinical decision making.

Factors influencing long-term outcomes in fibrotic interstitial lung disease (F-ILD) diagnosed through multidisciplinary discussion (MDD): a prospective cohort study

BackgroundThe diagnostic process for fibrotic interstitial lung disease (F-ILD) is notably intricate, necessitating a multidisciplinary discussion to achieve consensus based on both clinical and radiological features. This study investigated the shared and distinctive long-term mortality predictors among the two primary phenotypes of F-ILD, namely idiopathic pulmonary fibrosis (IPF) and connective tissue disease-associated interstitial lung disease (CTD-ILD).MethodsWe included patients with F-ILD diagnosed from December 2018 to December 2019 and conducted follow-up assessments until February 2023. Age, gender, usual interstitial pneumonia (UIP) pattern, gender–age–physiology (GAP) score, modified Medical Research Council (mMRC) dyspnea score, antifibrotic agent use, pulmonary function test parameters, and six-minute walking test (6MWT) parameters were recorded at baseline and used as mortality predictors in a multivariate Cox regression model.ResultsWe enrolled 104 ILD patients. The survival rate of non-IPF patients was more than twice that of IPF patients (78.9% vs. 34%, p < 0.001), and the survival rate of patients with a GAP score of 0–2 was more than twice that of patients with a score of > 2 (93.2% vs. 36.6%, p < 0.001). Older age, male gender, definite UIP pattern, higher GAP score, higher mMRC dyspnea score, lower forced expiratory volume in one second/forced vital capacity (FEV1/FVC), shorter 6MWT distance, and lower initial and final SpO2 were also associated with higher long-term mortality (p < 0.05). In multivariable analysis, only a GAP score of > 2 (hazard ratio [HR]:16.7; 95% confidence interval [CI] 3.28–85.14; p = 0.001) and definite UIP pattern (HR: 4.08; 95% CI 1.07–15.5; p = 0.039) were significantly associated with overall mortality.ConclusionThe long-term mortality rate of IPF patients was higher than that of CTD-ILD patients. The GAP score and UIP patterns were significant mortality predictors for both IPF and CTD-ILD patients.

Identification and functional prediction of long non-coding RNA and mRNA related to connective tissue disease-associated interstitial lung diseases.

Recently, the role of long non-coding RNA (lncRNA) in rheumatic immune diseases has attracted widespread attention. However, knowledge of lncRNA in connective tissue disease-associated interstitial lung disease (CTD-ILD) is limited. This study explored the expression profile and possible mechanisms of lncRNA and mRNA in peripheral blood mononuclear cells (PBMCs) of CTD-ILD patients, especially systemic sclerosis (SSc)-ILD and rheumatoid arthritis (RA)-ILD. LncRNA microarray analysis identified 240 diferentially expressed lncRNAs and 218 diferentially expressed mRNA in the CTD-ILD group and the connective tissue disease without associated interstitial lung disease (CTD-NILD) group. The bioinformatics analysis of diferential genes has identified several important biological processes and signal pathways, including nuclear factor kappa B (NF-kappa B) signaling pathway, interleukin 17 (IL-17) signaling pathway, B cell receptor signaling pathway. Relative expression levels of five diferentially expressed lncRNAs and one mRNA in 120 SSc and RA patients with or without ILD were detected by quantitative reverse-transcription (PCR). The ENST00000604692 expression level was significantly higher in the ILD than the without interstitial lung disease (NILD) group; T311354 and arginase-1 were significantly higher in SSc than RA group. These data suggest that the specific profile of lncRNA in PBMCs of CTD-ILD patients and the potential signal pathways related to the pathogenesis of CTD-ILD, which may provide newfound insights for the diagnosis and treatment of CTD-ILD patients.

Plasma LTBP2 as a potential biomarker in differential diagnosis of connective tissue disease-associated interstitial lung disease and idiopathic pulmonary fibrosis: a pilot study.

Few biomarkers distinguish connective tissue disease-associated interstitial lung disease (CTD-ILD) from idiopathic pulmonary fibrosis (IPF). Latent transforming growth factor-β binding protein-2 (LTBP2), a secreted extracellular matrix protein, is involved in pulmonary fibrosis. However, the role of LTBP2 in differentially diagnosing CTD-ILD and IPF is unclear. In this study, enzyme-linked immunosorbent assays quantified plasma LTBP2 concentrations in 200 individuals (35 healthy controls, 42 CTD patients without ILD, 89 CTD-ILD patients, and 34 IPF patients). CTD-ILD and IPF were further classified based on chest imaging pattern and pulmonary function test results. Plasma LTBP2 levels were significantly elevated in the IPF group compared with the CTD-ILD group. ROC analysis further suggested the possible value of LTBP2 in differentially diagnosing CTD-ILD and IPF. Additionally, CTD-ILD patients with progressive lung fibrosis had higher plasma LTBP2 concentrations than those who did not. Similarly, patients with IPF developing acute exacerbation showed higher plasma LTBP2 levels than those with stable IPF. This is the first study showing that LTBP2 was closely associated with the usual interstitial pneumonia (UIP) pattern in rheumatoid arthritis-associated ILD (RA-ILD). Moreover, the optimal cutoff values of LTBP2 for distinguishing IPF from CTD-UIP/RA-UIP were 33.75 and 38.33ng/mL with an AUC of 0.682 and 0.681, respectively. Our findings suggest that plasma LTBP2 levels may differentially diagnose CTD-ILD and IPF, and assess their fibrotic activity. Additionally, clinical LTBP2 evaluation may be a great aid to identifying the presence of the UIP pattern in RA-ILD and to discriminating IPF from CTD-UIP, particularly RA-UIP.

A computed tomography-based radiomics nomogram for predicting overall survival in patients with connective tissue disease-associated interstitial lung disease

ObjectivesAccurate prognostic prediction is beneficial for the management of patients with connective tissue disease-associated interstitial lung disease (CTD-ILD). The purpose of the present study was to develop and validate a nomogram using clinical features and computed tomography (CT) based radiomics features to predict overall survival (OS) in patients with CTD-ILD, and to assess the incremental prognostic value the radiomics might add to clinical risk factors. Materials & methodsPatients from two clinical centers with CTD-ILD were enrolled in the present retrospective study. A radiomics signature, a clinical model and a combined nomogram were developed and assessed in the cohorts. The incremental value of radiomics signature to the clinical independent risk factors in survival prediction was evaluated. The models were externally validated to evaluate the model generalization ability. ResultsA total of 215 patients (mean age, 53 years ± 14 [standard deviation], 45 men) were evaluated. Patients with higher radiomics scores had higher mortality risk than those with lower radiomics scores (Hazard ratio, 12.396; 95% CI, 3.364–45.680; P < 0.001). The combined nomogram showed better predictive capability than the clinical model did with higher C-indices (0.800, 0.738, 0.742 vs. 0.747, 0.631, 0.587 in the training, internal- and external-validation cohort, respectively), time-AUCs and overall net-benefit. ConclusionThe radiomics signature is a potential prognostic biomarker of CTD-ILD and add incremental value to the clinical independent risk factors. The combined nomogram can provide a more accurate estimation of OS than the clinical model for CTD-ILD patients. Clinical relevance statementThe developed combined nomogram showed accurate prognostic prediction performance, which is beneficial for the management of CTD-ILD patients. It also proved radiomics could extract prognostic information from CT images.

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

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. 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. 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 10months after confirmation of an ILD disease activity, and the group whose pulmonary fibrosis score at the beginning of nintedanib was <35%. 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).

Serum Rcn3 level is a potential diagnostic biomarker for connective tissue disease-associated interstitial lung disease and reflects the severity of pulmonary function

BackgroundAlthough reticulocalbin 3 (Rcn3) has a critical role in alveolar epithelial function as well as in pathogenesis of pulmonary fibrosis, no study has yet examined its diagnostic and prognostic values for interstitial lung disease (ILD). This study aimed to evaluate Rcn3 as a potential marker in differential diagnosis of idiopathic pulmonary fibrosis (IPF) and connective tissue disease-associated interstitial lung disease (CTD-ILD) and in reflecting the severity of disease.MethodsThis was a retrospective observational pilot study included 71 ILD patients and 39 healthy controls. These patients were stratified into IPF group (39) and CTD-ILD group (32). The severity of ILD was evaluated through pulmonary function test.ResultsSerum Rcn3 level was statistically higher in CTD-ILD patients than that in IPF patients (p = 0.017) and healthy controls (p = 0.010). Serum Rcn3 further showed statistically negative correlation with pulmonary function indexes (TLC% pred and DLCO% pred) and positive correlation with inflammatory indexes (CRP and ESR) (r = − 0.367, p = 0.039; r = − 0.370, p = 0.037; r = 0.355, p = 0.046; r = 0.392, p = 0.026, respectively) in CTD-ILD patients rather than IPF patients. ROC analysis demonstrated that serum Rcn3 had superior diagnostic value for CTD-ILD and a cutoff value of 2.73 ng/mL had a sensitivity of 69%, a specificity of 69% and an accuracy of 45% for diagnose of CTD-ILD.ConclusionsSerum Rcn3 levels might be a clinically useful biomarker in screening and evaluating CTD-ILD.

Rituximab for connective tissue disease-associated interstitial lung disease: A systematic review and meta-analysis.

To assess the efficacy of rituximab (RTX) on lung function and the prevalence of adverse events (AEs) in connective tissue disease-associated interstitial lung disease (CTD-ILD) by meta-analysis. EMBASE, Web of Science, PubMed and ClinicalKey were searched up to July 16, 2021. The lung function (forced vital capacity, FVC% predicted, and diffusing capacity of the lung for carbon monoxide, DLCO% predicted) and prevalence of AEs of RTX in CTD-ILD were analyzed by meta-analysis, and 95% confidence interval (CI) was calculated. Subgroup analyses and meta-regression were used to explore the heterogeneity. We identified 29 studies, including 827 CTD-ILD patients with a median age of 53.05 years. In observational studies, FVC% (mean difference - 1.24, 95% CI [-2.35, -0.12]; P=.030) and DLCO% (-7.71, [-11.79, -3.63]; P=.014) of CTD-ILD decreased significantly after RTX treatment. In randomized controlled trials, FVC% of CTD-ILD decreased after RTX treatment (-5.24, [-9.94, - 0.54]; P=.029), but the difference of DLCO% was not significant (1.15, [-4.33, 6.63]; P=.681). The prevalence of AEs, all-cause mortality and infections was 29.7% (95% CI [0.17, 0.42]), 11.6% (95% CI [0.08, 0.16]) and 20.9% (95% CI [0.15, 0.27]), respectively. RTX was associated with AEs such as decreased pulmonary function, all-cause mortality, and infections in CTD-ILD. Adverse reactions during and after RTX treatment should be carefully monitored. Further prospective studies are needed to compare RTX with other immunosuppressants, antifibrotic drugs or placebos, which can provide therapeutic approaches for CTD-ILD.

Serum MUC5AC protein levels are correlated with the development and severity of connective tissue disease-associated pulmonary interstitial lesions

BackgroundMucin 5AC (MUC5AC) and mucin 5B (MUC5B) are the major components of airway mucins. The expression levels of MUC5AC and MUC5B are related to connective tissue disease-associated interstitial lung disease (CTD-ILD) in the promoter region of MUC5AC and MUC5B and the relevant bronchoalveolar lavage fluid. However, the serum protein levels of MUC5AC and MUC5B have not been tested in CTD-ILD patients. In this study, we tested the serum levels of MUC5AC and MUC5B proteins in CTD-ILD patients and assessed their relationship with the occurrence and development of ILD.MethodsSerum samples were obtained from 168 CTD and 80 healthy participants from the First Affiliated Hospital of Xiamen University. The serum levels of MUC5AC and MUC5B proteins were measured by enzyme-linked immunosorbent assay.ResultsOf the 168 individuals with CTD, 70 had primary Sjögren’s syndrome (pSS), 64 had systemic sclerosis (SSc), and 34 had polymyositis/dermatomyositis (PM/DM). There were 116 cases with concurrent ILD; ILD scores were 1 (n=23), 2 (n=41), and 3 (n=52). Serum MUC5AC and MUC5B protein levels were considerably higher in CTD-ILD than CTD-only individuals or healthy controls (both p<0.005). Among the CTD subgroups, MUC5AC was higher in individuals with concurrent ILD than in those without ILD (all p<0.05). MUC5AC was positively correlated with ILD severity in all three CTD subgroups (all R>0.47 and all p<0.05). The MUC5B levels varied substantially between SSc and SSc patients with concurrent ILD (p=0.032) and were related to ILD severity only in PM/DM patients (R=0.346 and p=0.045).ConclusionMUC5AC is correlated with the occurrence and development of ILD, while MUC5B is associated with ILD diagnosis and severity in CTD subgroups. Serum MUC5AC levels present a definite diagnostic utility for CTD-ILD and as proxies for its severity.

Pirfenidone inhibits cell fibrosis in connective tissue disease-associated interstitial lung disease by targeting the TNF-α/STAT3/KL6 pathway.

BackgroundTo explore the effect and mechanism of pirfenidone in inhibiting pulmonary fibrosis in connective tissue disease-associated interstitial lung disease (CTD-ILD).MethodsFrom 2018 to 2020, 50 CTD-ILD patients were enrolled in the clinical study. Based on whether pirfenidone was used during treatment, patients were enrolled into the pirfenidone group and the control group. Pulmonary function tests were compared before and after treatment. Enzyme-linked immunosorbent assay (ELISA) was performed to detect the expression of tumor necrosis factor-α (TNF-α), signal transducer and activator of transcription 3 (STAT3), and Krebs Von den Lungen-6 (KL-6) in venous blood before and after treatment. Rat type II (RLE-6TN) lung epithelial cells were cultivated for in vitro experiments, and they were sorted into the control group, bleomycin group, pirfenidone group, TNF-α group, Stattic group, and TNF-α/Stattic combined treatment group. For the in vitro experiments, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) tests were used to evaluate cell proliferation, Reverse Transcription-Polymerase Chain Reaction(RT–PCR) was performed to detect STAT3 and KL-6 mRNA expression levels, ELISA was utilized to detect TNF-α and E-cadherin expression levels, and Western blotting (WB) was performed to determine α-smooth muscle actin (α-SMA), vimentin, TNF-α, STAT3, phosphorylated signal transducer and activator of transcription 3 (PSTAT3) and KL-6 expression.ResultsIn the clinical study, the pulmonary function indices including forced expiratory volume in one second (FEV1), forced vital capacity (FVC), FEV1/FVC, peak expiratory flow (PEF) and partial pressure (PaO2) of the patients in the study group were superior to those in the control group (P<0.05). The serum TNF-α, STAT3 and KL-6 levels in the study group were significantly lower than those in the control group (P<0.05). In the in vitro experiments, the α-SMA, vimentin, STAT3 and KL-6 levels in the treatment group were significantly lower than those in the bleomycin group (P<0.05). Compared with those in the pirfenidone group, the α-SMA, vimentin, STAT3 and KL-6 levels in the TNF-α-treated group were significantly upregulated (P<0.05). Meanwhile, cell viability was further upregulated (P<0.05), and the expression of STAT3 and KL-6 was further decreased in the Stattic-treated group (P<0.05). In the group treated with infliximab combined with Stattic, TNF-α expression was significantly increased (P<0.05), cell activity was significantly restored (P<0.05), and the STAT3, KL-6 and E-cadherin expression levels were inhibited (P<0.05).ConclusionsPirfenidone improved pulmonary function 1 and decreased TNF-α, STAT3, and KL-6 expression in CTD-ILD patients. Moreover, pirfenidone inhibits cell fibrosis through the TNF-α/STAT3/Mucin 1(MUC1) pathway.

Human epididymis protein 4 is associated with severity and poor prognosis of connective tissue disease-associated interstitial lung disease with usual interstitial pneumonia pattern

BackgroundOverexpression of human epididymis protein 4 (HE4) was previously described in idiopathic pulmonary fibrosis (IPF), but whether serum HE4 can be considered as a potential biomarker in connective tissue disease-associated interstitial lung disease (CTD-ILD) with usual interstitial pneumonia (UIP) pattern was still unknown. MethodA total of 55 CTD-ILD patients with UIP pattern (UIP-CTD) and 52 healthy controls were enrolled in this study. The serum levels of HE4 and Krebs von den Lungen-6 (KL-6) were evaluated in both cohorts. In addition, immunohistochemistry analysis for HE4 was performed on the lung sections of 6 patients with rheumatoid arthritis-associated UIP (UIP-RA) and 6 patients with early-stage lung cancer as normal control. ResultsThe levels of serum HE4 and KL-6 were higher in patients with UIP-CTD than in healthy controls (292.3 pmol/L versus 79.5 pmol/L for HE4, p < 0.001; 1091.0 IU/mL versus 171.5 IU/mL for KL-6, p < 0.001). Significant correlations between serum HE4 levels and percentpredicted forced vital capacity (FVC%) (r = -0.425, p = 0.004), percent predicted diffusing capacity of the lung for carbon monoxide (DLCO%) (r = -0.447, p = 0.003), and Gender-Age-Physiology (GAP) index (r = 0.494, p < 0.001) were observed in UIP-CTD patients. In immunohistochemistry analysis, elevated expression of HE4 in bronchiolar epithelium and mesenchyme was observed in patients with UIP-RA compared with controls. The serum levels of HE4 (≥277.5 pmol/L) and GAP index were related to an increased risk of mortality (HR = 3.884, p = 0.034; HR = 1.480, p = 0.028, respectively). ConclusionThe expression of HE4 in serum and lung specimens was significantly elevated in UIP-CTD patients. Moreover, serum HE4 may be utilized as a biomarker to evaluate the severity of disease and predict the prognosis of UIP-CTD patients.

Quantitative evaluation of disease severity in connective tissue disease-associated interstitial lung disease by dual-energy computed tomography

BackgroundHigh-resolution computed tomography (HRCT) is recommended diagnosing and monitoring connective tissue disease-associated interstitial lung disease (CTD-ILD). Quantitative computed tomography has the potential to precisely assess the radiological severity of CTD-ILD, but has still been under study.ObjectiveTo investigate whether dual-energy computed tomography (DECT), a novel quantitative technique, can be used for quantitative severity assessment in CTD-ILD.MethodsThis cross sectional study recruited adult CTD-ILD patients who underwent DECT scans from the ICE study between October 2019 and November 2021. DECT parameters, including effective atomic number (Zeff), lung (lobe) volume, and monochromatic CT number (MCTN) of each lung lobe, were evaluated. CTD-ILD was classified into extensive CTD-ILD and limited CTD-ILD by staging algorithm using combined forced vital capacity (FVC)%predicted and total extent of ILD (TEI) on CT. Dyspnea, cough, and life quality were scored by Borg dyspnea score, Leicester cough questionnaire (LCQ), and short-form 36 health survey questionnaire (SF-36), respectively.ResultsThere was a total of 147 patients with DECT scans enrolled. Higher Zeff value (3.104 vs 2.256, p < 0.001), higher MCTN (− 722.87 HU vs − 802.20 HU, p < 0.001), and lower lung volume (2309.51cm3 vs 3475.21cm3, p < 0.001) were found in extensive CTD-ILD compared with limited CTD-ILD. DECT parameters had significant moderate correlations with FVC%predicted (|r|= 0.542–0.667, p < 0.01), DLCO%predicted (|r|= 0.371–0.427, p < 0.01), and TEI (|r|= 0.485–0.742, p < 0.01). Receiver operating characteristic (ROC) analysis indicated MCTN averaged over the whole lung had the best performance for extensive CTD-ILD discrimination (AUC = 0.901, cut-off: − 762.30 HU, p < 0.001), with a sensitivity of 82.1% and a specificity of 85.4%. The Zeff value was the independent risk factor for dyspnea (OR = 3.644, 95% CI: 1.846–7.192, p < 0.001) and cough (OR = 3.101, 95% CI: 1.528–6.294, p = 0.002), and lung volume significantly contributed to the mental component summary (MCS) in SF-36 (standardized β = 0.198, p < 0.05).ConclusionsDECT can be applied to evaluate the severity of CTD-ILD.

Prediction of long-term mortality by using machine learning models in Chinese patients with connective tissue disease-associated interstitial lung disease

BackgroundThe exact risk assessment is crucial for the management of connective tissue disease-associated interstitial lung disease (CTD-ILD) patients. In the present study, we develop a nomogram to predict 3‑ and 5-year mortality by using machine learning approach and test the ILD-GAP model in Chinese CTD-ILD patients.MethodsCTD-ILD patients who were diagnosed and treated at the First Affiliated Hospital of Zhengzhou University were enrolled based on a prior well-designed criterion between February 2011 and July 2018. Cox regression with the least absolute shrinkage and selection operator (LASSO) was used to screen out the predictors and generate a nomogram. Internal validation was performed using bootstrap resampling. Then, the nomogram and ILD-GAP model were assessed via likelihood ratio testing, Harrell’s C index, integrated discrimination improvement (IDI), the net reclassification improvement (NRI) and decision curve analysis.ResultsA total of 675 consecutive CTD-ILD patients were enrolled in this study, during the median follow-up period of 50 (interquartile range, 38–65) months, 158 patients died (mortality rate 23.4%). After feature selection, 9 variables were identified: age, rheumatoid arthritis, lung diffusing capacity for carbon monoxide, right ventricular diameter, right atrial area, honeycombing, immunosuppressive agents, aspartate transaminase and albumin. A predictive nomogram was generated by integrating these variables, which provided better mortality estimates than ILD-GAP model based on the likelihood ratio testing, Harrell’s C index (0.767 and 0.652 respectively) and calibration plots. Application of the nomogram resulted in an improved IDI (3- and 5-year, 0.137 and 0.136 respectively) and NRI (3- and 5-year, 0.294 and 0.325 respectively) compared with ILD-GAP model. In addition, the nomogram was more clinically useful revealed by decision curve analysis.ConclusionsThe results from our study prove that the ILD-GAP model may exhibit an inapplicable role in predicting mortality risk in Chinese CTD-ILD patients. The nomogram we developed performed well in predicting 3‑ and 5-year mortality risk of Chinese CTD-ILD patients, but further studies and external validation will be required to determine the clinical usefulness of the nomogram.

Association of Red Blood Cell Distribution Width Levels with Connective Tissue Disease-Associated Interstitial Lung Disease (CTD-ILD).

Objective The aim of this study was to evaluate the diagnostic and prognostic value of red blood cell distribution width (RDW) in patients with connective tissue disease-associated interstitial lung disease (CTD-ILD). Methods We retrospectively reviewed 213 CTD-ILD patients and 97 CTD patients without ILD from February 2017 to February 2020. Hospital and office records were used as data sources. CTD-ILD patients were followed up. Results Patients with CTD-ILD had significantly higher RDW than those with CTD without ILD (p < 0.001). The area under the receiver operating characteristic curve (AUROC) of RDW for discriminating CTD-ILD from CTD without ILD was 0.64 (95% CI: 0.57-0.70, p < 0.001). The cutoff value of RDW for discriminating CTD-ILD from CTD without ILD was 13.95% with their corresponding specificity (55.9%) and sensitivity (70.1%). Correlation analyses showed that the increased RDW was significantly correlated with decreased DLCO%predicted (r = −0.211, p = 0.002). Cox multiple regression analysis indicated that RDW (HR = 1.495, p < 0.001) was an independent factor in the survival of CTD-ILD. The best cutoff value of RDW to predict the survival of patients with CTD-ILD was 14.05% (AUC = 0.78, 95% CI: 0.72-0.84, p < 0.001). The log-rank test showed a significant difference in survival between the two groups (RDW > 14.05% and RDW < 14.05%). Conclusion RDW was higher in CTD-ILD patients and had a negative correlation with DLCO%predicted. RDW may be an important serum biomarker for severity and prognosis of patients with CTD-ILD.

Serum Biomarkers in Differential Diagnosis of Idiopathic Pulmonary Fibrosis and Connective Tissue Disease-Associated Interstitial Lung Disease.

Introduction: The goal of this study is to determine whether Advanced glycosylated end-products (AGE), Advanced oxidation protein products (AOPP) and Matrix metalloproteinase 7 (MMP7) could be used as differential biomarkers for idiopathic pulmonary fibrosis (IPF) and connective tissue disease-associated interstitial lung disease (CTD-ILD). Method: Seventy-three patients were enrolled: 29 with IPF, 14 with CTD-ILD, and 30 healthy controls. The study included a single visit by participants. A blood sample was drawn and serum was analysed for AGE using spectrofluorimetry, AOPP by spectrophotometry, and MMP7 using sandwich-type enzyme-linked immunosorbent assay. Results: AGE, AOPP and MMP7 serum levels were significantly higher in both IPF and CTD-ILD patients versus healthy controls; and AGE was also significantly elevated in CTD-ILD compared to the IPF group. AGE plasma levels clearly distinguished CTD-ILD patients from healthy participants (AUC = 0.95; 95% IC 0.86–1), whereas in IPF patients, the distinction was moderate (AUC = 0.78; 95% IC 0.60–0.97). Conclusion: In summary, our results provide support for the potential value of serum AGE, AOPP and MMP7 concentrations as diagnostic biomarkers in IPF and CTD-ILD to differentiate between ILD patients and healthy controls. Furthermore, this study provides evidence, for the first time, for the possible use of AGE as a differential diagnostic biomarker to distinguish between IPF and CTD-ILD. The value of these biomarkers as additional tools in a multidisciplinary approach to IPF and CTD-ILD diagnosis needs to be considered and further explored. Multicentre studies are necessary to understand the role of AGE in differential diagnosis.

Safety and efficacy of rituximab in connective tissue disease-associated interstitial lung disease: A systematic review and meta-analysis

ObjectiveRituximab (RTX) is widely used in the treatment of connective tissue disease (CTD) because it can target and eliminate pathogenic B cells. Interstitial lung disease (ILD) is one of the common complications of CTD; however, the clinical benefits of RTX in connective tissue disease-associated interstitial lung disease (CTD-ILD) are still controversial. This meta-analysis was performed to systematically evaluate the efficacy and safety of RTX in CTD-ILD patients. MethodsWe performed a systematic online query in PubMed, Cochrane, and Embase up to February 2020. Randomized controlled trials and observational studies on the use of RTX and conventional treatment in CTD-ILD patients were comprehensively reviewed and investigated. ResultsIn total, 6 studies, including 242 participants, were analysed. The pooled results showed that RTX is superior to conventional treatment methods in improving forced vital capacity and modified Rodnan skin scores (MRSS) in patients with systemic sclerosis (P＜0. 05), but there was no statistically significant difference between RTX and conventional treatment method in the improvement of lung diffusion function. The risk of adverse effects declined in the RTX therapy groups compared with the conventional therapy groups in terms of infection and the blood system. ConclusionThe pooled results of this meta-analysis indicated that RTX is well tolerated, and RTX is able to improve or stabilize pulmonary function in CTD-ILD patients.

Risk of primary graft dysfunction following lung transplantation in selected adults with connective tissue disease-associated interstitial lung disease

Previous studies have reported similarities in long-term outcomes following lung transplantation for connective tissue disease-associated interstitial lung disease (CTD-ILD) and idiopathic pulmonary fibrosis (IPF). However, it is unknown whether CTD-ILD patients are at increased risk of primary graft dysfunction (PGD), delays in extubation, or longer index hospitalizations following transplant compared to IPF patients. We performed a multicenter retrospective cohort study of CTD-ILD and IPF patients enrolled in the Lung Transplant Outcomes Group registry who underwent lung transplantation between 2012 and 2018. We utilized mixed effects logistic regression and stratified Cox proportional hazards regression to determine whether CTD-ILD was independently associated with increased risk for grade 3 PGD or delays in post-transplant extubation and hospital discharge compared to IPF. A total of 32.7% (33/101) of patients with CTD-ILD and 28.9% (145/501) of patients with IPF developed grade 3 PGD 48-72 hours after transplant. There were no significant differences in odds of grade 3 PGD among patients with CTD-ILD compared to those with IPF (adjusted OR 1.12, 95% CI 0.64-1.97, p = 0.69), nor was CTD-ILD independently associated with a longer post-transplant time to extubation (adjusted HR for first extubation 0.87, 95% CI 0.66-1.13, p = 0.30). However, CTD-ILD was independently associated with a longer post-transplant hospital length of stay (median 23 days [IQR 14-35 days] vs17 days [IQR 12-28 days], adjusted HR for hospital discharge 0.68, 95% CI 0.51-0.90, p = 0.008). Patients with CTD-ILD experienced significantly longer postoperative hospitalizations compared to IPF patients without an increased risk of grade 3 PGD.

Dissociation between airway and systemic autoantibody responses in chronic obstructive pulmonary disease

BackgroundAutoimmune processes have been implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). However, the relationship between airway and systemic autoantibody responses remains unclear. The aim of this study was to elucidate this relationship in patients with stable COPD by investigating the correlation patterns between sputum and serum autoantibodies.MethodsIn this cross-sectional study, sputum supernatant and serum obtained from 47 patients with stable COPD were assayed for the presence of IgG antibodies against ten autoantigens: Smith antigen (Sm), ribosomal phosphoprotein P0 (P0), Ro/Sjögren syndrome type A antigen (Ro/SSA), La/Sjögren syndrome type B antigen (La/SSB), DNA topoisomerase I (Scl-70), histidyl-tRNA synthetase (Jo-1), U1 small nuclear ribonucleoprotein (U1-SnRNP), thyroid peroxidase (TPO), proteinase-3 (PR3), and myeloperoxidase (MPO). A second cohort of 55 stable COPD patients was recruited for validation, and a group of 59 non-COPD controls and a group of 20 connective-tissue disease-associated interstitial lung disease (CTD-ILD) patients were also recruited for comparison. Hierarchical clustering and network analysis were used to evaluate the correlation patterns between sputum and serum autoantibody profiles.ResultsBoth hierarchical clustering and network analysis showed that sputum and serum autoantibody profiles were distinct in either analytic COPD cohort or validation cohort. In contrast, the autoantibodies of the two compartments in non-COPD controls and CTD-ILD patients were inadequately distinguished using either hierarchical clustering or network analysis. Many autoantibodies in the sputum were found to have significant correlations with lung function, symptom score and frequency of prior exacerbations in COPD patients, but the antibodies in the serum were not.ConclusionsWe observed a dissociation between sputum autoantibodies and serum autoantibodies in patients with stable COPD, suggesting that airway and systemic immune status may play very different roles in the disease. Sputum autoantibodies are more clinically relevant than serum autoantibodies. Focusing on airway autoimmunity may help improve understanding of the immunopathological mechanism of COPD.

Mechanical ventilation for acute respiratory failure due to idiopathic pulmonary fibrosis versus connective tissue disease-associated interstitial lung disease: Effectiveness and risk factors for death.

Relatively little is known about the effects of mechanical ventilation (MV; including invasive MV [IMV] and noninvasive ventilation) on clinical outcomes of patients with idiopathic pulmonary fibrosis (IPF) and connective tissue disease-associated interstitial lung disease (CTD-ILD) in the intensive care unit (ICU) and risk factors for ICU death remain to be determined. Our objective was to determine and compare mortality rates between IPF and CTD-ILD patients receiving MV and to identify risk factors for ICU death in these patients. We conducted a retrospective cohort study in respiratory ICUs of three university hospitals in China during a 7-year period. We compared clinical data and outcomes between patients with IPF and those with CTD-ILD and performed logistic regression analyses to identify risk factors for ICU death. Of the 94 patients in the analyses, 63 were diagnosed with IPF and 31 were diagnosed with CTD-ILD. ICU mortality was significantly higher in the IPF group than in the CTD-ILD group (86% vs 68%; P=0.041) and was significantly lower in patients receiving noninvasive ventilation than in those receiving IMV (62% vs 88%; P=0.004). Risk factors for ICU death were disease progression as the principal cause of acute respiratory failure and IMV. Based on current clinical practice in three ICUs, the mortality rate in IPF patients receiving MV might reach 86% and is higher than in CTD-ILD patients. IMV might be initiated cautiously, especially in patients with disease progression as the principal cause of acute respiratory failure.

Vitamin D levels are prognostic factors for connective tissue disease associated interstitial lung disease (CTD-ILD).

Objective: Vitamin D deficiency was associated with CTD-ILD and reduced lung function. We sought to confirm that lower Vitamin D level would be related to shorter survival times.Results: The CTD-ILD patients had lower Vitamin D level(P<0.05). Among patients with CTD-ILD who have improved lung function after treatment, elevation of Vitamin D level was positively associated with ΔFVC (%), ΔFEV1(%) and ΔDLCO-SB (%). The median survival time of patients with high serum 25(OH)D level was significantly longer than the patients with low 25(OH)D level group (16.5 months vs14.0 months, P=0.007). The Vitamin D was identified as an independent prognostic factor with a hazard ratio of 0.869 (95% CI 0.772-0.977, P =0.019).Conclusions: Vitamin D level was lower in patients with CTD-ILD and associated with poor prognosis. Continuous levels of Vitamin D may be an important serum biomarker of prognosis.Methods: 85 CTD-ILD patients, 71 Idiopathic pulmonary fibrosis (IPF) patients and 78 healthy control patients were included in the study. In the subgroup analysis, the CTD-ILD patients were divided into anti-MDA5 antibody-positive group and anti-MDA5 antibody-negative group according to the serum autoantibodies results. The survival analysis evaluated effect of Vitamin D level on disease prognosis.