Results: A total of 147 patients were randomly assigned to receive BI 1015550 or placebo. Among patients without background antifibrotic use, the median change in the FVC was 5.7 ml (95% credible interval, -39.1 to 50.5) in the BI 1015550 group and -81.7 ml (95% credible interval, -133.5 to -44.8) in the placebo group (median difference, 88.4 ml; 95% credible interval, 29.5 to 154.2; probability that BI 1015550 was superior to placebo, 0.998). Among patients with background antifibrotic use, the median change in the FVC was 2.7 ml (95% credible interval, -32.8 to 38.2) in the BI 1015550 group and -59.2 ml (95% credible interval, -111.8 to -17.9) in the placebo group (median difference, 62.4 ml; 95% credible interval, 6.3 to 125.5; probability that BI 1015550 was superior to placebo, 0.986). A mixed model with repeated measures analysis provided results that were consistent with those of the Bayesian analysis. The most frequent adverse event was diarrhea. A total of 13 patients discontinued BI 1015550 treatment owing to adverse events. The percentages of patients with serious adverse events or severe adverse events were similar in the two trial groups.

Conclusions: In this placebo-controlled trial, treatment with BI 1015550, either alone or with background use of an antifibrotic agent, prevented a decrease in lung function in patients with idiopathic pulmonary fibrosis. (Funded by Boehringer Ingelheim; 1305-0013 ClinicalTrials.gov number, NCT04419506.).

Results: There were 58 deaths (72%, median survival = 17 months). Annual % change in ALV was most significantly related to annual % change in FVC (R2 = 0.26, p < 0.0001). On multivariate analysis, annual % change in ASD predicted mortality (HR = 0.97, p < 0.001), whereas change in FVC did not. A 25% decline in annual % change in ASD best predicted mortality, superior to 10% decline in FVC and fibrosis progression.

Conclusion: In IPF, serial decline in CT markers of lung volume and, specifically, annualised 25% reduction in aortosternal distance provides evidence of disease progression, not always identified by FVC trends or changes in fibrosis extent.

Results: A quarter (26%; 40/153) of the patients were suffering from malnutrition at baseline, which was more frequent (62%) in patients whose BMI was <25 kg/m2. Patients whose baseline FFMI was low were more likely to be hospitalized (Hazard Ratio (HR) = 1.98 [95% confidence interval, 1.15; 3.41], P = 0.0139) and/or die (HR = 1.79 [1.11; 2.89], P = 0.0165), but their acute exacerbation rate was similar to that of patients with normal FFMIs. Decreased food intake (SEFI®<7) at baseline was associated with all-cause hospitalization (P = 0.003) and mortality (P < 0.0001) during follow-up. Baseline higher gender-age-physiology (GAP) scores (HR = 1.24 [1.01; 1.52], P = 0.0434; HR = 1.71 [1.37; 2.14], P < 0.0001, respectively), lower BMI (HR = 0.89 [0.83; 0.96], P = 0.003; HR = 0.89 [0.82; 0.96], P = 0.003), and decreased food intake (SEFI® score) (HR = 0.81 [0.71; 0.93], P = 0.003; HR = 0.72 [0.64; 0.81], P < 0.0001), but not FFMI, were independently associated with all-cause hospitalization and mortality rates during follow-up.

Conclusions: Malnutrition and decreased food intake at IPF diagnosis are associated with all-cause hospitalization and mortality. Future studies will determine whether dedicated interventions to improve food intake and nutritional status could improve outcomes for IPF patients.

Findings: We identified three clusters of patients with IPF with statistically significant differences in lung function (p=0.009) and mortality (p=0.009) between groups. Gene enrichment analysis implicated mitochondrial homeostasis, apoptosis, cell cycle and innate and adaptive immunity in the pathogenesis underlying these groups. We developed and validated a 13-gene cluster classifier that predicted mortality in IPF (high-risk clusters vs low-risk cluster: HR 4.25, 95% CI 2.14 to 8.46, p=3.7×10-5).

Interpretation: We have identified blood gene expression signatures capable of discerning groups of patients with IPF with significant differences in survival. These clusters could be representative of distinct pathophysiological states, which would support the theory of multiple endotypes of IPF. Although more work must be done to confirm the existence of these endotypes, our classifier could be a useful tool in patient stratification and outcome prediction in IPF.

Results: In total, 277 patients were enrolled in the PROOF registry. During the follow-up period, worsening in cough VAS score, SGRQ symptom score, and SGRQ activity score was observed, while EQ-5D VAS, SGRQ total score, and SGRQ impact score remained stable. During univariate analyses, EQ-5D VAS and all SGRQ sub-scores and total score at baseline were associated with mortality; however, during multivariate analyses, only the SGRQ total score, SGRQ impact score, and SGRQ symptom score at baseline were associated with mortality. During the follow-up period, 261 (94.2%) patients required an outpatient consultation (IPF- or non-IPF-related) and there were 182 hospitalizations in total, most of which were respiratory related (66.5%).

Conclusions: The PROOF registry provided valuable, real-world data on the association between baseline QoL and mortality, and longitudinal HCRU and QoL outcomes in patients with IPF over 24 months and identified that SGRQ may be an independent prognostic factor in IPF.

Patients with idiopathic pulmonary fibrosis (IPF) have a high risk of developing lung cancer compared with the general population. The morbidity of lung cancer in IPF patient ranges from 3% to 22%, and in some cases exceeds 50%, and these patients have a reduced survival time. However, the mechanisms through which IPF increases the morbidity and mortality in lung cancer remain unclear. By carefully analyzing the pathological features of these two diseases, we uncovered that, first, similar to IPF, lung carcinomas are more frequently found in the peripheral area of the lungs and, second, lung cancers tend to develop from the honeycomb areas in IPF. In accordance with the above pathological features, due to the spatial location, the peripheral areas of the lung experience a high stretch force because the average distance between adjacent alveolar cells in this area tends to be larger than that at the central lung when inflated; furthermore, the honeycomb areas, comprised of condensed fibrous tissue, are characterized by increased stiffness. Both of these pathological features of lung cancer and IPF are coincidentally related to abnormal mechanical forces (stretch and tissue stiffness). Therefore, we believe that the aberrant mechanical forces that are generated in the lung with IPF may contribute to the onset and progression of lung cancer. In this review, we discuss the possible effects of mechanical forces that are generated in IPF on the initiation and progression of lung cancer from the perspective of the hallmarks of cancer, including proliferation, metastasis, angiogenesis, cancer stem cells, immunology, epigenetics, and metabolism, so as to advance our understanding of the pathogenesis of IPF-related lung cancer and to harness these concepts for lung cancer mechanotherapies.

Results: 1) Update of IPF: A conditional recommendation was made to regard transbronchial lung cryobiopsy as an acceptable alternative to surgical lung biopsy in centers with appropriate expertise. No recommendation was made for or against genomic classifier testing. Conditional recommendations were made against antacid medication and antireflux surgery for the treatment of IPF. 2) PPF: PPF was defined as at least two of three criteria (worsening symptoms, radiological progression, and physiological progression) occurring within the past year with no alternative explanation in a patient with an ILD other than IPF. A conditional recommendation was made for nintedanib, and additional research into pirfenidone was recommended.

Conclusions: The conditional recommendations in this guideline are intended to provide the basis for rational, informed decisions by clinicians.

Results: 1) Update of IPF: A conditional recommendation was made to regard transbronchial lung cryobiopsy as an acceptable alternative to surgical lung biopsy in centers with appropriate expertise. No recommendation was made for or against genomic classifier testing. Conditional recommendations were made against antacid medication and antireflux surgery for the treatment of IPF. 2) PPF: PPF was defined as at least two of three criteria (worsening symptoms, radiological progression, and physiological progression) occurring within the past year with no alternative explanation in a patient with an ILD other than IPF. A conditional recommendation was made for nintedanib, and additional research into pirfenidone was recommended.

Conclusions: The conditional recommendations in this guideline are intended to provide the basis for rational, informed decisions by clinicians.

Results: Radiomic profiling identified two clinically and prognostically distinct SSc-ILD patient clusters. To evaluate the clinical applicability, we derived and externally validated a binary, quantitative radiomic risk score (qRISSc) composed of 26 features that accurately predicted PFS and significantly improved upon clinical risk stratification parameters in multivariable Cox regression analyses in the pooled cohorts. A high qRISSc score, which identifies patients at risk for progression, was reverse translatable from human to experimental ILD and correlated with fibrotic pathway activation.

Conclusions: Radiomics-based risk stratification using routine CT images provides complementary phenotypic, clinical and prognostic information significantly impacting clinical decision making in SSc-ILD.

Results: The combined analysis comprised 1257 subjects treated with nintedanib and 1042 subjects who received placebo. Nintedanib reduced the rate of decline in FVC (mL/year) over 52 weeks by 51.0% (95% CI 39.1, 63.0) compared with placebo. The relative effect (95% CI) was the same using the fixed effect and random effects models. There was no evidence of heterogeneity in the relative treatment effect of nintedanib across the populations studied (I2 = 0%, τ2 = 0, p = 0.93).

Conclusions: A meta-analysis of data from four placebo-controlled trials demonstrated that nintedanib approximately halved the rate of decline in FVC over 52 weeks across subjects with different forms of pulmonary fibrosis, with no evidence of heterogeneity in its relative treatment effect across patient populations.

Objective: To conduct a systematic review to evaluate existing ILD literature to determine whether patients with progressive pulmonary fibrosis (PPF) should be treated with the antifibrotic nintedanib.

Conclusions: Nintedanib use in patients with PPF is associated with a statistically significant decrease in disease progression but increase in gastrointestinal side effects regardless of the radiographic pattern of pulmonary fibrosis. However, limitations in the available evidence lead to low certainty in these effect estimates and make definitive conclusions about the differential effects by subtype of ILD difficult to determine.

Objective: To perform a new systematic review to inform updated guidelines.

Results: Histopathologic diagnostic yield (number of procedures that yielded a histopathologic diagnosis divided by the total number of procedures performed) of TBLC was 80% (95% CI 76-83%) in patients with ILD. TBLC was complicated by bleeding and pneumothorax in 30% (95% CI 20-41%) and 8% (95% CI 6-11%) of patients, respectively. Procedure-related mortality, severe bleeding, prolonged air leak, acute exacerbation, respiratory failure, and respiratory infection were rare. The quality of the evidence was very low due to the uncontrolled study designs, lack of consecutive enrollment, and inconsistent results.

Conclusion: Very low-quality evidence indicated that TBLC has a diagnostic yield of approximately 80% in patients with ILD, with manageable complications.

Idiopathic pulmonary fibrosis (IPF) is a progressive and often lethal interstitial lung disease of unknown aetiology. IPF is characterised by myofibroblast activation, tissue stiffening, and alveolar epithelium injury. As current IPF treatments fail to halt disease progression or induce regeneration, there is a pressing need for the development of novel therapeutic targets. In this regard, tri-dimensional (3D) models have rapidly emerged as powerful platforms for disease modelling, drug screening and discovery. In this review, we will touch on how 3D in vitro models such as hydrogels, precision-cut lung slices, and, more recently, lung organoids and lung-on-chip devices have been generated and/or modified to reveal distinct cellular and molecular signalling pathways activated during fibrotic processes. Markedly, we will address how these platforms could provide a better understanding of fibrosis pathophysiology and uncover effective treatment strategies for IPF patients.

In coronavirus disease 2019 (COVID-19) patients, dysregulated release of matrix metalloproteinases occurs during the inflammatory phase of acute respiratory distress syndrome (ARDS), resulting in epithelial and endothelial injury with excessive fibroproliferation. COVID-19 resembles idiopathic pulmonary fibrosis (IPF) in several aspects. The fibrotic response in IPF is driven primarily by an abnormally activated alveolar epithelial cells (AECs) which release cytokines to activate fibroblasts. Endoplasmic reticulum (ER) stress is postulated to be one of the early triggers in both diseases. Systemic sclerosis (SSc) is a heterogeneous autoimmune rare connective tissue characterised by fibrosis of the skin and internal organs. Interstitial lung disease (ILD) is a common complication and the leading cause of SSc-related death. Several corollaries have been discussed in this paper for new drug development based on the pathogenic events in these three disorders associated with pulmonary fibrosis. A careful consideration of the similarities and differences in the pathogenic events associated with the development of lung fibrosis in post-COVID patients, IPF patients and patients with SSc-ILD may pave the way for precision medicine. Several questions need to be answered through research, which include the potential role of antifibrotics in managing IPF, SSc-ILD and post-COVID fibrosis. Many trials that are underway will ultimately shed light on their potency and place in therapy.

Recent findings: Screening for ILD has been augmented by the use of artificial intelligence, ultra-low dose computerized tomography (CT) of the chest, and the use of chest ultrasound. Serum biomarkers have not found their way into clinical practice as yet. Identifying patients who need treatment and choosing the appropriate therapy is important to minimize the risk of therapy-related toxicity. The first-line drugs for systemic sclerosis (SSc) ILD include mycophenolate and cyclophosphamide. Nintedanib, an anti-fibrotic tyrosine kinase inhibitor, is approved for use in SSc-ILD. The US Food and Drug Administration (FDA) has recently approved tocilizumab subcutaneous injection for slowing the rate of decline in pulmonary function in adult patients with SSc-ILD. Autologous stem cell transplantation may have a role in select cases of SSc-ILD.

Summary: CTD-ILD is a challenging area with diverse entities and variable outcomes. High-resolution CT is the investigative modality of choice. Treatment decisions need to be individualized and are based on patient symptoms, lung function, radiologic abnormalities, and the risk of disease progression. Precision medicine may play an important role in determining the optimal therapy for an individual patient in the future.

Recent findings: All patients with SSc are at risk of ILD and should be screened for ILD at diagnosis using a high-resolution computed tomography (HRCT) scan. Some patients with SSc-ILD develop a progressive phenotype characterized by worsening fibrosis on HRCT, decline in lung function, and early mortality. To evaluate progression and inform treatment decisions, regular monitoring is important and should include pulmonary function testing, evaluation of symptoms and quality of life, and, where indicated, repeat HRCT. Multidisciplinary discussion enables comprehensive evaluation of the available information and its implications for management. The first-line treatment for SSc-ILD is usually immunosuppression. The antifibrotic drug nintedanib has been approved for slowing lung function decline in patients with SSc-ILD. Optimal management of patients with SSc-ILD requires a multidisciplinary and patient-centered approach.

Systemic sclerosis (SSc, scleroderma) is a complex connective tissue disorder characterized by multisystem clinical manifestations resulting from immune dysregulation/autoimmunity, vasculopathy, and, most notably, progressive fibrosis of the skin and internal organs. In recent years, it has been observed that the main drivers of SSc-related tissue fibrosis are myofibroblasts, a type of mesenchymal cells with both the extracellular matrix-synthesizing features of fibroblasts and the cytoskeletal characteristics of contractile smooth muscle cells. The accumulation and persistent activation of pro-fibrotic myofibroblasts during SSc development and progression result in elevated mechanical stress and reduced matrix plasticity within the affected tissues and may be ascribed to a reduced susceptibility of these cells to pro-apoptotic stimuli, as well as their increased formation from tissue-resident fibroblasts or transition from different cell types. Given the crucial role of myofibroblasts in SSc pathogenesis, finding the way to inhibit myofibroblast differentiation and accumulation by targeting their formation, function, and survival may represent an effective approach to hamper the fibrotic process or even halt or reverse established fibrosis. In this review, we discuss the role of myofibroblasts in SSc-related fibrosis, with a special focus on their cellular origin and the signaling pathways implicated in their formation and persistent activation. Furthermore, we provide an overview of potential therapeutic strategies targeting myofibroblasts that may be able to counteract fibrosis in this pathological condition.

Idiopathic pulmonary fibrosis (IPF) is a fatal chronic interstitial lung disease with no established treatment and is characterized by progressive scarring of the lung tissue and an irreversible decline in lung function. Chronic inflammation has been demonstrated to be the pathological basis of fibrosis. Emerging studies have revealed that most interleukin-17 (IL-17) isoforms are essential for the mediation of acute and chronic inflammation via innate and adaptive immunity. Overexpression or aberrant expression of IL-17 cytokines contributes to various pathological outcomes, including the initiation and exacerbation of IPF. Here, we aim to provide an overview of IL-17 family members in the pathogenesis of IPF.

By evaluating S100 calcium binding protein A9 (S100A9) and Klebs von den Lungen-6 (KL-6) expression in patients with 4 common interstitial lung diseases (ILDs), we aimed to investigate whether S100A9 or KL-6 can be of any value in the differential diagnosis of these ILDs and simultaneously signal the disease progression.We collected the data of patients diagnosed with the 4 ILDs and underwent fiber-optic bronchoscopy and BAL in the First Affiliated Hospital, China Medical University from January 2012 to December 2020. The data related to BGA, C-reactive protein, pulmonary function test, total number and fraction of cells, T lymphocyte subsets in bronchoalveolar lavage fluid (BALF), and the expression of S100A9 and KL-6 in BALF and serum were collected. We analyzed, whether S100A9 or KL-6 could serve as a biomarker for differential diagnosis between the 4 common ILDs; whether the levels of S100A9 and KL-6 correlated with each other; whether they were correlated with other clinical parameters and disease severity.This study included 98 patients, 37 patients with idiopathic pulmonary fibrosis (IPF), 12 with hypersensitivity pneumonitis, 13 with connective tissue disease-associated ILD, and 36 with sarcoidosis (SAR): stage I (18), stage II (9), stage III (5), and stage IV (4). The expression of KL-6 in BALF was significantly higher in IPF patients than other 3 groups (all P-value < .05). However, there was no significant difference in the levels of S100A9 in BALF and serum between the 4 groups (P-value > .05). The levels of S100A9 in BALF of IPF patients was positively and significantly correlated with KL-6 expression and the percentage of neutrophils in BALF (P-value < .05). Along with the stage increase of SAR patients, the level of S100A9 in BALF gradually increased, which was negatively and significantly correlated with the forced vital capacity/predicted, carbon monoxide diffusing capacity/predicted%, and PaO2 (all P-value < .05).The expression of KL-6 in BALF can be used as a biomarker to differentiate IPF from the other 3 common ILDs. While, this was not the case with expression of S100A9 in BALF and serum. However, the expression S100A9 in BALF is useful to indicate the progression of SAR. Thus, simultaneous measurement of KL-6 and S100A9 levels in BALF makes more sense in differential diagnosing of the 4 common ILDS.

Interstitial lung disease (ILD) represents a significant cause of morbidity and mortality in systemic sclerosis (SSc). The purpose of this study was to examine recirculating lymphocytes from SSc patients for potential biomarkers of interstitial lung disease (ILD). Peripheral blood mononuclear cells (PBMCs) were isolated from patients with SSc and healthy controls enrolled in the Vanderbilt University Myositis and Scleroderma Treatment Initiative Center cohort between 9/2017-6/2019. Clinical phenotyping was performed by chart abstraction. Immunophenotyping was performed using both mass cytometry and fluorescence cytometry combined with t-distributed stochastic neighbor embedding analysis and traditional biaxial gating. This study included 34 patients with SSc-ILD, 14 patients without SSc-ILD, and 25 healthy controls. CD21lo/neg cells are significantly increased in SSc-ILD but not in SSc without ILD (15.4 ± 13.3% vs. 5.8 ± 0.9%, p = 0.002) or healthy controls (5.0 ± 0.5%, p < 0.0001). While CD21lo/neg B cells can be identified from a single biaxial gate, tSNE analysis reveals that the biaxial gate is comprised of multiple distinct subsets, all of which are increased in SSc-ILD. CD21lo/neg cells in both healthy controls and SSc-ILD are predominantly tBET positive and do not have intracellular CD21. Immunohistochemistry staining demonstrated that CD21lo/neg B cells diffusely infiltrate the lung parenchyma of an SSc-ILD patient. Additional work is needed to validate this biomarker in larger cohorts and longitudinal studies and to understand the role of these cells in SSc-ILD.

Results: We observed that IL-22, IL-23 as well as IL-17 were significantly increased in the serum of lung cancer patients associated IPF; moreover, the results of ROC curve showed that the expression of IL-22, IL-23 and IL-17 can distinguish the lung cancer patients with lung cancer-associated IPF group; finally, the expression of IL-22, IL-23 and IL-17 was positively correlated with the degree of differentiation and metathesis of the tumor.

Conclusion: In conclusion, we first reported that IL-22, IL-23 and IL-17 were elevated in the serum of patients with lung cancer-associated IPF, and our data may provide novel evidence for the prevention and treatment of lung cancer-associated IPF.

The new radiological diagnostic criteria for diagnosing idiopathic pulmonary fibrosis (IPF) seek to optimize the indications for surgical lung biopsy (SLB). We applied the new criteria to a retrospective series of patients with interstitial lung disease (ILD) who underwent SLB in order to analyse the correlation between the radiological findings suggestive of another diagnosis (especially mosaic attenuation and its location with respect to fibrotic areas) and the usual interstitial pneumonia (UIP) pathologic diagnosis. Two thoracic radiologists reviewed the HRCT images of 83 patients with ILD and SLB, describing the radiological findings and patterns based on the new criteria. The association of each radiological finding with radiological patterns and histology was analysed. Mosaic attenuation is highly prevalent in both the UIP and non-UIP pathologic diagnosis and with similar frequency (80.0% vs. 78.6%). However, the presence of significant mosaic attenuation (≥ 3 lobes) only in non-fibrotic areas was observed in 60.7% of non-UIP pathologic diagnosis compared to 20.0% in UIP. This finding was associated with other diagnoses different from IPF, mostly connective tissue disease-associated interstitial lung disease (CTD-ILD) and hypersensitivity pneumonitis (HP). In our series of pathologically confirmed ILD, mosaic attenuation in non-fibrotic areas was a predictor of non-UIP pathologic diagnosis, and was associated with other diagnoses different from UIP, mostly CTD-ILD and HP. If confirmed in larger series, this finding could constitute a valuable tool for improving the interpretation of radiological.

Results: The literature review identified 36 signs/symptoms and 43 impacts directly or indirectly related to pulmonary aspects of PF-ILD. The most relevant symptoms identified by participants included shortness of breath on exertion, fatigue and cough; relevant impacts included effects on physical functioning, activities of daily living and emotional wellbeing. These are presented in a conceptual model. Consensus opinion was that existing PROMs need further modification and validation before use in clinical trials.

Conclusions: The conceptual model improves understanding of the symptoms and impacts that living with PF-ILD has on patients' wellbeing. It can help to inform the choice of PROMs in clinical trials and highlight aspects to assess in the clinical care of patients with PF-ILD.

Results: Our study revealed that systemic delivery of bleomycin induced limited, acute inflammation that resolved. The distinct inflammatory phase preceded a slow, gradually progressive fibrogenesis that was shown to be both time-dependent and dose-dependent. The fibrosis phase exhibited characteristics that better resembles human disease with focal regions of fibrosis that were predominantly found in peribronchovascular areas and in subpleural regions; central lung areas contained relatively less fibrosis.

Conclusion: This model provides a preclinical tool that will allow researchers to study the mechanism of pulmonary fibrosis in HPS and provide a platform for the development of therapeutics to treat HPSPF. This method can be applied on studies of IPF or other monogenic disorders that lead to pulmonary fibrosis.

IPF is a devastating lung disease with limited therapeutic possibilities. FGF19, an endocrine FGF, was recently shown to decrease liver fibrosis. To ask whether FGF19 had anti-fibrotic properties in the lung and decipher its effects on common features associated with lung fibrogenesis. We assessed, by Elisa, FGF19 levels in plasma and bronchoalveolar lavage fluids (BALF)obtained from controls and IPF patients. In vivo, using an intravenously administered adeno11 associated virus (AAV), we overexpressed FGF19 at the fibrotic phase of two experimental models of murine lung fibrosis and assessed its effect on lung morphology, lung collagen content, fibrosis markers and pro fibrotic mediator expression, at mRNA and protein levels. In vitro, we investigated whether FGF19 could modulate the TGFβ-induced differentiation of primary human lung fibroblast into myofibroblast and the apoptosis of murine alveolar type II cell. While FGF19 was not detected in BALF, FGF19 concentration was decreased in the plasma of IPF patients compared to controls. In vivo, the overexpression of FGF19 was associated with a marked decrease of lung fibrosis and fibrosis markers, with a decrease of pro fibrotic mediator expression and lung collagen content. In vitro, FGF19 decreased alveolar type 2 epithelial cell apoptosis through the decrease of the proapoptotic BIM protein expression and prevented TGF-ß induced myofibroblast differentiation through the inhibition of JNK phosphorylation. Altogether these data identify FGF19 as an anti-fibrotic molecule with a potential therapeutic interest in fibrotic lung disorders.

Idiopathic pulmonary fibrosis (IPF) is a severe fibrotic lung disease characterized by irreversible scarring of the lung parenchyma leading to dyspnea, progressive decline in lung function, and respiratory failure. We analyzed lung transcriptomic data from independent IPF cohorts using weighted gene co-expression network analysis (WGCNA) to identify gene modules based on their preservation status in these cohorts. The consensus gene modules were characterized by leveraging existing clinical and molecular data such as lung function, biological processes, pathways, and lung cell types. From a total of 32 consensus gene modules identified, two modules were found to be significantly correlated with the disease, lung function, and preserved in other IPF datasets. The upregulated gene module was enriched for extracellular matrix, collagen metabolic process, and BMP signaling while the downregulated module consisted of genes associated with tube morphogenesis, blood vessel development, and cell migration. Using a combination of connectivity-based and trait-based significance measures, we identified and prioritized 103 "hub" genes (including 25 secretory candidate biomarkers) by their similarity to known IPF genetic markers. Our validation studies demonstrate the dysregulated expression of CRABP2, a retinol-binding protein, in multiple lung cells of IPF, and its correlation with the decline in lung function.

Results: Thirty-four MCTD patients (121 visits) and 102 SSc patients (424 visits) were included. At baseline, MCTD patients presented with interstitial lung disease, cardiac involvement, synovitis and myositis more frequently compared to SSc patients, while use of immunosuppressive medication was less frequent. In both groups, mean SF36 scores were lower than in the general Dutch population. The SF36 subscore "general health perception" was impacted most in both groups (MCTD: 38.5 [SD:7.0], SSc: 39.9 [SD:8.9]). During follow-up, SF36 scores improved in MCTD patients, while EQ5DNL remained stable. No specific characteristics were identified that associated with baseline HRQoL or change in HRQol over time.

Conclusions: Like in SSc, HRQoL in MCTD is significantly impaired, especially the general health perception of patients. Evaluation in larger prospective cohorts is needed to identify characteristics that impact HRQol most.