Serum heat shock protein 47 levels in patients with drug-induced lung disease

A Fatal Case of Drug-Induced Lung Injury Potentially Related to Olanzapine

Drug-induced lung injury (DILI) occurs when exposure to a drug leads to inflammation and, eventually, fibrosis of the lung interstitium. While DILI is a rare side effect of antipsychotic medication, once it manifests, it requires detailed investigation and prompt treatment. Diagnosing DILI can be challenging at times due to its similarity to conditions such as infectious diseases or interstitial pneumonia induced by other causes. We hereby report a fatal case of suspected DILI associated with olanzapine. A 61-year-old female with a history of delusional disorder was admitted to our hospital due to worsened psychiatric symptoms. Ten milligrams of olanzapine had been initiated a week prior to admission by a psychiatrist at the local clinic to control these symptoms. After admission, although the patient claimed no respiratory symptoms, she developed a slight fever and deterioration of chest radiologic findings. Bronchoalveolar lavage revealed a progressively bloody return of fluid, suggesting pulmonary alveolar hemorrhage. Since no respiratory disorders have been noted, and considering the exclusion of other potential diagnoses, DILI was strongly suspected. Although olanzapine was promptly discontinued, the patient's condition rapidly deteriorated. Despite high-dose steroid therapy, the patient's response to treatment was inadequate, and she finally succumbed to the illness. This case highlights that olanzapine may induce lung injury similar to other psychiatric drugs. Furthermore, early diagnosis and treatment are essential for patients with psychiatric disorders who may sometimes present with fewer symptoms.

Drug-induced interstitial lung disease: a narrative review of a clinical conundrum

INTRODUCTION

Drug-induced interstitial lung disease (DI-ILD) is increasing in incidence, due to the use of many new drugs across a broad range of cancers and chronic inflammatory diseases. The presentation and onset of DI-ILD are variable even for the same drug across different individuals. Clinical suspicion is essential for identifying these conditions, with timely drug cessation an important determinant of outcomes.

AREAS COVERED

This review provides a comprehensive and up-to-date summary of epidemiology, risk factors, pathogenesis, diagnosis, treatment, and prognosis of DI-ILD. Relevant research articles from PubMed and Medline searches up to September 2023 were screened and summarized. Specific drugs including immune checkpoint inhibitors, CAR-T cell therapy, methotrexate, and amiodarone are discussed in detail. The potential role of pharmacogenomic profiling for lung toxicity risk is considered.

EXPERT OPINION

DI-ILD is likely to be an increasingly important contributor to respiratory disability in the community. These conditions can negatively impact quality of life and patient longevity, due to associated respiratory compromise as well as cessation of evidence-based therapy for the underlying disease. This clinical conundrum is relevant to all areas of medicine, necessitating increased understanding and greater vigilance for drug-related lung toxicity.

HSP47: A Therapeutic Target in Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease characterized by a progressive decline in lung function and poor prognosis. The deposition of the extracellular matrix (ECM) by myofibroblasts contributes to the stiffening of lung tissue and impaired oxygen exchange in IPF. Type I collagen is the major ECM component and predominant collagen protein deposited in chronic fibrosis, suggesting that type I collagen could be a target of drugs for fibrosis treatment. Heat shock protein 47 (HSP47), encoded by the serpin peptidase inhibitor clade H, member 1 gene, is a stress-inducible collagen-binding protein. It is an endoplasmic reticulum-resident molecular chaperone essential for the correct folding of procollagen. HSP47 expression is increased in cellular and animal models of pulmonary fibrosis and correlates with pathological manifestations in human interstitial lung diseases. Various factors affect HSP47 expression directly or indirectly in pulmonary fibrosis models. Overall, understanding the relationship between HSP47 expression and pulmonary fibrosis may contribute to the development of novel therapeutic strategies.

Case report: Irinotecan-induced interstitial lung disease in an advanced colorectal cancer patient resurfacing decades after allogeneic bone marrow transplantation for aplastic anemia; a case report and narrative review of literature

Two mechanisms of drug-induced interstitial lung disease (DILD) have been reported: 1) direct injury of lung epithelial cells and/or endothelial cells in lung capillaries by the drug and/or its metabolites and 2) hypersensitivity reactions. In both mechanisms, immune reactions such as cytokine and T cell activation are involved in DILD. While past and present lung diseases and accumulative lung damage due to smoking and radiation are risk factors for DILD, the association between the immune status of the host and DILD is not well known. Herein, we report a case of advanced colorectal cancer with a history of allogeneic bone marrow transplantation for aplastic anemia more than 30 years prior, in which DILD occurred early after irinotecan-containing chemotherapy. Bone marrow transplantation might be a potential risk factor for DILD.

Pulmonary Toxicity and Proteomic Analysis in Bronchoalveolar Lavage Fluids and Lungs of Rats Exposed to Copper Oxide Nanoparticles

Copper oxide nanoparticles (CuO NPs) were intratracheally instilled into lungs at concentrations of 0, 0.15, and 1.5 mg/kg bodyweight to 7-week-old Sprague-Dawley rats. The cytotoxicity, immunotoxicity, and oxidative stress were evaluated, followed by proteomic analysis of bronchoalveolar lavage fluid (BALF) and lungs of rats. The CuO NPs-exposed groups revealed dose-dependent increases in total cells, polymorphonuclear leukocytes, lactate dyhydrogenase, and total protein levels in BALF. Inflammatory cytokines, including macrophage inflammatory protein-2 and tumor necrosis factor-α, were increased in the CuO NPs-treated groups. The expression levels of catalase, glutathione peroxidase-1, and peroxiredoxin-2 were downregulated, whereas that of superoxide dismutase-2 was upregulated in the CuO NPs-exposed groups. Five heat shock proteins were downregulated in rats exposed to high concentrations of CuO NPs. In proteomic analysis, 17 proteins were upregulated or downregulated, and 6 proteins were validated via Western blot analysis. Significant upregulation of 3-hydroxy-3-methylglutaryl-CoA synthase and fidgetin-like 1 and downregulation of annexin II, HSP 47 and proteasome α1 occurred in the CuO NPs exposed groups. Taken together, this study provides additional insight into pulmonary cytotoxicity and immunotoxicity as well as oxidative stress in rats exposed to CuO NPs. Proteomic analysis revealed potential toxicological biomarkers of CuO NPs, which also reveals the toxicity mechanisms of CuO NPs.

Stratifin as a novel diagnostic biomarker in serum for diffuse alveolar damage

Among the various histopathological patterns of drug-induced interstitial lung disease (DILD), diffuse alveolar damage (DAD) is associated with poor prognosis. However, there is no reliable biomarker for its accurate diagnosis. Here, we show stratifin/14-3-3σ (SFN) as a biomarker candidate found in a proteomic analysis. The study includes two independent cohorts (including totally 26 patients with DAD) and controls (total 432 samples). SFN is specifically elevated in DILD patients with DAD, and is superior to the known biomarkers, KL-6 and SP-D, in discrimination of DILD patients with DAD from patients with other DILD patterns or other lung diseases. SFN is also increased in serum from patients with idiopathic DAD, and in lung tissues and bronchoalveolar lavage fluid of patients with DAD. In vitro analysis using cultured lung epithelial cells suggests that extracellular release of SFN occurs via p53-dependent apoptosis. We conclude that serum SFN is a promising biomarker for DAD diagnosis.

Serum Biomarkers in a Radiological Pattern of Non-Fibrotic Hypersensitivity Pneumonitis: Implications for Mechanistic Difference and Differential Diagnosis

Hypersensitivity pneumonitis (HP) is a consequence of immune-mediated reactions caused by recurrent exposure to environmental agents. Recently, clinical practice guidelines for the diagnosis of HP were published and increased interest in HP. On the other hand, novel therapies have recently emerged for various diseases, and the management of drug-related pneumonitis (DRP) has become increasingly important. Among DRP, the HP pattern (DRP-HP) shows small, poorly defined centrilobular nodules with or without widespread areas of ground-glass opacity or lobular areas of decreased attenuation and vascularity. A similar radiological pattern of non-fibrotic HP can be induced, irrespective of inhalation (non-fibrotic HP) or intravenous administration (DRP-HP). However, their difference has not been well described, although the distribution of lesions in the lungs was slightly different between these two conditions. In this review, we focus on serum biomarkers of lung epithelial cells in order to investigate the difference between DRP-HP and non-fibrotic HP (common-HP). Serum levels of Krebs von den Lungen 6 (KL-6) might be relatively lower (occasionally normal) in DRP-HP than in common-HP, implying a mechanistic difference. KL-6 could be useful in discriminating between DRP and non-fibrotic HP (common type).

Acute Exacerbation of Idiopathic Pulmonary Fibrosis

Acute exacerbation is a major cause of morbidity and mortality in patients with idiopathic pulmonary fibrosis. Although the real nature of it is still not clear and there is no proven effective therapy, progress has been made since the consensus definition and diagnostic criteria were proposed. The trial results of several new innovative therapies in idiopathic pulmonary fibrosis have suggested a potential for benefit in acute exacerbation of idiopathic pulmonary fibrosis, leading to double blind randomized clinical trials in this area. This article reviews the present knowledge on acute exacerbation of idiopathic pulmonary fibrosis, focusing on the triggering factors and treatment.

KL-6 as an Immunological Biomarker Predicts the Severity, Progression, Acute Exacerbation, and Poor Outcomes of Interstitial Lung Disease: A Systematic Review and Meta-Analysis

Object

Interstitial lung disease (ILD) is a specific form of chronic fibrosing interstitial pneumonia with various etiology. The severity and progression of ILD usually predict the poor outcomes of ILD. Otherwise, Krebs von den Lungen-6 (KL-6) is a potential immunological biomarker reflecting the severity and progression of ILD. This meta-analysis is to clarify the predictive value of elevated KL-6 levels in ILD.

Method

EBSCO, PubMed, and Cochrane were systematically searched for articles exploring the prognosis of ILD published between January 1980 and April 2021. The Weighted Mean Difference (WMD) and 95% Confidence Interval (CI) were computed as the effect sizes for comparisons between groups. For the relationship between adverse outcome and elevated KL-6 concentration, Hazard Ratio (HR), and its 95%CI were used to estimate the risk factor of ILD.

Result

Our result showed that ILD patients in severe and progressive groups had higher KL-6 levels, and the KL-6 level of patients in the severe ILD was 703.41 (U/ml) than in mild ILD. The KL-6 level in progressive ILD group was 325.98 (U/ml) higher than that in the non-progressive ILD group. Secondly, the KL-6 level of patients in acute exacerbation (AE) of ILD was 545.44 (U/ml) higher than stable ILD. Lastly, the higher KL-6 level in ILD patients predicted poor outcomes. The KL-6 level in death of ILD was 383.53 (U/ml) higher than in survivors of ILD. The pooled HR (95%CI) about elevated KL-6 level predicting the mortality of ILD was 2.05 (1.50–2.78), and the HR (95%CI) for progression of ILD was 1.98 (1.07–3.67).

Conclusion

The elevated KL-6 level indicated more severe, more progressive, and predicted the higher mortality and poor outcomes of ILD.

The Prognostic Value of Krebs von den Lungen-6 and Surfactant Protein-A Levels in the Patients with Interstitial Lung Disease

Background and Objectives

The highly variable clinical course of interstitial lung disease (ILD) makes it difficult to predict patient prognosis. Serum surfactant protein-A (SP-A) and Krebs von den Lungen-6 (KL-6) are known prognostic biomarkers. However, the clinical or pathophysiological differences in patients with these biomarkers have not been well evaluated. We investigated the clinical and pathophysiological differences through the comparison of SP-A and KL-6 levels before and after treatment.

Methods

This study included retrospective data from 91 patients who were treated for ILD between August 2015 and September 2019. Serum SP-A and KL-6 levels were measured before and after treatment. The patients were followed up for 3 months.

Results

Changes in the serum biomarkers (Delta SP-A and Delta KL-6) were found to be significantly correlated (rs = 0.523, P < 0.001); Delta SP-A and Delta KL-6 were inversely correlated with changes in pulmonary function (% predicted values of diffusing capacity for carbon monoxide [DLCO], forced vital capacity [FVC], and forced expiratory volume in 1 s [FEV1]). Patients were divided into four groups based on their Delta SP-A and Delta KL-6 levels in a cluster analysis (G1, G2, G3, and G4). Both SP-A and KL-6 were elevated in the G1 group, with all the patients enrolled classified as progressive or unchanged, and 86.4% of patients showed improved disease activity in the G4 group, where both SP-A and KL-6 levels were reduced. In the G2 group, only SP-A levels decreased post-treatment, indicating an improvement in respiratory function; the patients were not at the end stage of the disease. Only the SP-A levels increased in the G3 group with immunosuppressive treatment.

Conclusions

Reduced serum SP-A and/or KL-6 levels are associated with improved lung function in patients with ILD. Some patients only showed a decrease in SP-A levels could prognosis an improvement in respiratory function. When only SP-A is increased, it may imply that the patients are at an early stage of disease progression. As a result, for proper disease monitoring, measuring both markers is important.

Drug-related pneumonitis with radiographic hypersensitivity pneumonitis pattern: Three case series

Novel therapies have recently emerged for various diseases, and the management of drug-related pneumonitis (DRP) has become increasingly important. In particular, the hypersensitivity pneumonitis (HP) pattern of DRP has been increasingly recognized due to development of new therapeutic strategies, such as immunotherapy. However, literature describing detailed clinical cases is still lacking.

Herein, we report three cases of DRP with typical HP radiographic pattern. These patients were treated with different drugs, namely nano albumin-bound (nab)-paclitaxel, everolimus, or nivolumab, but had common clinical features, including a good prognosis.

Extracellular Heat Shock Proteins as Therapeutic Targets and Biomarkers in Fibrosing Interstitial Lung Diseases

Interstitial lung diseases (ILDs) include a large number of diseases and causes with variable outcomes often associated with progressive fibrosis. Although each of the individual fibrosing ILDs are rare, collectively, they affect a considerable number of patients, representing a significant burden of disease. Idiopathic pulmonary fibrosis (IPF) is the typical chronic fibrosing ILD associated with progressive decline in lung. Other fibrosing ILDs are often associated with connective tissues diseases, including rheumatoid arthritis-ILD (RA-ILD) and systemic sclerosis-associated ILD (SSc-ILD), or environmental/drug exposure. Given the vast number of progressive fibrosing ILDs and the disparities in clinical patterns and disease features, the course of these diseases is heterogeneous and cannot accurately be predicted for an individual patient. As a consequence, the discovery of novel biomarkers for these types of diseases is a major clinical challenge. Heat shock proteins (HSPs) are molecular chaperons that have been extensively described to be involved in fibrogenesis. Their extracellular forms (eHSPs) have been recently and successfully used as therapeutic targets or circulating biomarkers in cancer. The current review will describe the role of eHSPs in fibrosing ILDs, highlighting the importance of these particular stress proteins to develop new therapeutic strategies and discover potential biomarkers in these diseases.

Protective Role of Genetic Variants in HSP90 Genes-Complex in COPD Secondary to Biomass-Burning Smoke Exposure and Non-Severe COPD Forms in Tobacco Smoking Subjects

Background: Chronic Obstructive Pulmonary Disease (COPD) is an inflammatory disease characterized by airflow obstruction, commonly present in smokers and subjects exposed to noxious particles product of biomass-burning smoke (BBS). Several association studies have identified single-nucleotide polymorphisms (SNP) in coding genes related to the heat shock proteins family-genes that codify the heat shock proteins (Hsp). Hsp accomplishes critical roles in regulating immune response, antigen-processing, eliminating protein aggregates and co-activating receptors. The presence of SNPs in these genes can lead to alterations in immune responses. We aimed to evaluate the association of SNPs in the HSP90 gene complex and COPD. Methods: We enrolled 1549 participants, divided into two comparison groups; 919 tobacco-smoking subjects (cases COPD-TS n = 294 and, controls SWOC n = 625) and 630 chronic exposed to BBS (cases COPD-BBS n = 186 and controls BBES n = 444). We genotyped 2 SNPs: the rs13296 in HSP90AB1 and rs2070908 in HSP90B1. Results: Through the dominant model (GC + CC), the rs2070908 is associated with decreased risk (p < 0.01, OR = 0.6) to suffer COPD among chronic exposed BBS subjects. We found an association between rs13296 GG genotype and lower risk (p = 0.01, OR = 0.22) to suffer severe COPD-TS forms in the severity analysis. Conclusions: single-nucleotide variants in the HSP90AB1 and HSP90B1 genes are associated with decreased COPD risk in subjects exposed to BBS and the most severe forms of COPD in tobacco-smoking subjects.

Anti-HSP47 siRNA lipid nanoparticle ND-L02-s0201 reverses interstitial pulmonary fibrosis in preclinical rat models

ND-L02-s0201 is a lipid nanoparticle encapsulating an siRNA which inhibits expression of heat shock protein 47 (HSP47), a collagen-specific chaperone. Accumulated evidence demonstrates a close association between increased level of HSP47 and excessive accumulation of collagen in fibrotic diseases. Our objective was to test ND-L02-s0201 efficacy in preclinical lung fibrosis models and characterise the downstream histological and functional consequences of inhibiting the expression of HSP47. Comprehensive optimisation and characterisation of bleomycin (BLM) and silica-induced rat lung fibrosis models were conducted, which ensured progressive pathological changes were sustained throughout the study during evaluation of the anti-fibrotic potential of ND-L02-s0201. In the BLM model, we demonstrated dose-dependent and statistically significant reduction in the relative lung weight, collagen deposition and histology, and fibrosis scores following ND-L02-s0201 treatment. Lung tissue mRNA profiling demonstrated that 11 out of 84 fibrosis-relevant genes were upregulated following BLM induction and were downregulated by approximately 4.5-fold following ND-L02-s0201 treatment. Epithelial-mesenchymal transition was characterised in the BLM model following ND-L02-s0201 treatment. Cell enrichment demonstrated that myofibroblasts contained the highest HSP47 mRNA expression. BLM led to more than a five-fold increase in myofibroblasts and ND-L02-s0201 treatment reduced the myofibroblasts to sham levels. Statistically significant improvement in lung function was noted in the BLM model which was determined by running endurance capacity using a 7-minute treadmill test. Comparable anti-fibrotic efficacy was also observed in the silica model. Results from two robust chronic rodent models of pulmonary fibrosis demonstrated significant anti-fibrotic effects and improved lung function which support the evaluation of ND-L02-s0201 in subjects with idiopathic pulmonary fibrosis.

HSP47: a potential target for fibrotic diseases and implications for therapy

Introduction: Chronic fibrotic disorders are challenging clinical problems. The major challenge is the identification of specific targets expressed selectively in fibrotic tissues. Collagen accumulation is the hallmark fibrosis. HSP47 is a collagen-specific chaperon with critical role in collagen folding. This review discusses the anti-fibrotic potential of HSP47. Areas covered: This review compiles data retrieved from the PubMed database with keywords 'HSP47+fibrosis' from 01/2005 to 06/2020. We examined 1) collagen biology and its role in fibrotic diseases, 2) HSP47 role in fibrosis, 3) HSP47 inhibition strategies and 4) clinical investigations. The identification of the HSP47-collagen binding site led to the development of methods to screen HSP47 inhibitors with anti-fibrotic potential. Specific in vivo  delivery systems of HSP47 siRNA to fibrotic tissue reduced collagen production/secretion associated with fibrosis inhibition in preclinical models. This strategy is about to be tested in clinical trials. Expert opinion: As a collagen-specific chaperon, HSP47 is a promising therapeutic target in fibrosis. Preclinical models have shown encouraging anti-fibrotic results. Anti-HSP47 strategies need to be further evaluated in clinical trials. The increase in circulating-HSP47 in lung fibrosis patients highlights the potential of HSP47 as a noninvasive biomarker and may represent an important step toward personalized medicine in fibrotic disorders.

Presence of heat shock protein 47-positive fibroblasts in cancer stroma is associated with increased risk of postoperative recurrence in patients with lung cancer

Background

Heat shock protein 47 (HSP47), a collagen-binding protein, has a specific role in the intracellular processing of procollagen production. HSP47 expression is associated with cancer growth and metastasis in several types of cancers. However, none of the studies have assessed whether HSP47 expression is associated with the risk of postoperative recurrence of lung cancer until now. Therefore, we aimed to assess this association.

Methods

The study population consisted of a cohort of consecutive patients who underwent surgery for lung cancer at Nagasaki University Hospital, Nagasaki, Japan, from January 2009 to December 2010. Patient characteristics, survival and disease-free survival (DFS), and laboratory findings were compared between patients who tested positive and negative for HSP47 expression in lung cancer cells and between those who showed high and low numbers of HSP47-positive fibroblasts in cancer stroma.

Results

A total of 133 patients underwent surgery for lung cancer. Sixty-seven patients (50.4%) had HSP47-positive cancer cells, and 91 patients (68.4%) had a higher number of HSP47-positive fibroblasts. The patients with a high number of HSP47-positive fibroblasts had a shorter DFS than those with a low number of HSP47-positive fibroblasts. Multivariate analysis identified only the presence of a high number of HSP47-positive fibroblasts as an independent risk factor for recurrence of lung cancer after surgery (odds ratio, 4.371; 95% confidence interval, 1.054–29.83; P = 0.042).

Conclusion

The present study demonstrated that the presence of a high number of HSP47-positive fibroblasts in the cancer stroma was a risk factor for recurrence of lung cancer after surgery.

[Drug-induced interstitial lung disease: approaches to diagnostics and treatment]

Drug-induced interstitial lung disease (D-ILD) can be caused by various drugs, including antibiotics, amiodarone, antitumor, rheumatological and non-steroidal anti-inflammatory drugs. D-ILD includes hypersensitivity reactions, organizing and non-specific interstitial pneumonia, eosinophilic lung diseases, diffuse alveolar damage and alveolar hypoventilation. To exclude other causes of pulmonary diseases, an assessment of the medical history, physical data and examination results, which may include chest X-ray/multispiral computed tomography (MSCT), lung function tests, and bronchoscopy with bronchoalveolar lavage, are necessary. Diagnosis of D-ILD is difficult due to the heterogeneity of clinical, radiological and histological data. The X-ray pathological phenotype of D-ILD is different; a specific MSCT pattern has not been identified. Treatment includes drug withdrawal and, in some cases, glucocorticoid therapy, although there are no prospective studies on their effect on the outcome of the disease. This article provides various drugs that cause ILD, approaches to their diagnosis and treatment.

Drug-Induced Interstitial Lung Disease: A Systematic Review

Background: Drug-induced interstitial lung disease (DIILD) occurs as a result of numerous agents, but the risk often only becomes apparent after the marketing authorisation of such agents. Methods: In this PRISMA-compliant systematic review, we aimed to evaluate and synthesise the current literature on DIILD. Results: Following a quality assessment, 156 full-text papers describing more than 6000 DIILD cases were included in the review. However, the majority of the papers were of low or very low quality in relation to the review question (78%). Thus, it was not possible to perform a meta-analysis, and descriptive review was undertaken instead. DIILD incidence rates varied between 4.1 and 12.4 cases/million/year. DIILD accounted for 3–5% of prevalent ILD cases. Cancer drugs, followed by rheumatology drugs, amiodarone and antibiotics, were the most common causes of DIILD. The radiopathological phenotype of DIILD varied between and within agents, and no typical radiological pattern specific to DIILD was identified. Mortality rates of over 50% were reported in some studies. Severity at presentation was the most reliable predictor of mortality. Glucocorticoids (GCs) were commonly used to treat DIILD, but no prospective studies examined their effect on outcome. Conclusions: Overall high-quality evidence in DIILD is lacking, and the current review will inform larger prospective studies to investigate the diagnosis and management of DIILD.

Soluble thrombomodulin in bronchoalveolar lavage fluid is an independent predictor of severe drug-induced lung injury

BACKGROUND AND OBJECTIVE

Drug-induced lung injury (DLI) can result from a vast number of agents, and sometimes presents findings similar to those of acute respiratory distress syndrome (ARDS). Previous studies have reported that circulating levels of soluble thrombomodulin (TM) reflect endothelial injuries, which play key roles in the development of ARDS. We hypothesized that endothelial injuries are an important aspect of pathogenesis in severe DLI. The primary aim of this study was to examine the associations between soluble TM and disease severity in DLI patients.

METHODS

Of the 2580 patients who underwent a bronchoalveolar lavage (BAL) procedure at Tosei General Hospital between May 2007 and February 2015, we retrospectively analysed the data of 68 DLI patients. Soluble TM in plasma and BAL fluid (BALF), and other biomarkers were included in our analysis.

RESULTS

At the time of diagnosis, 39 patients (57%) had respiratory failure (partial pressure of oxygen/inspiratory oxygen fraction ratio, PaO₂ /FiO₂ ratio < 300). There was a significant negative linear correlation between the PaO₂ /FiO₂ ratio and soluble TM in BALF (r = -0.448, P < 0.001). In a stepwise multiple regression analysis, soluble TM in BALF and surfactant protein D (SP-D) were the only independent determinants of the PaO₂ /FiO₂ ratio. Additionally, in a multivariate logistic regression model, soluble TM in BALF (adjusted OR (aOR): 7.48, 95% CI: 1.60-34.98) and SP-D (aOR: 5.31, 95% CI: 1.40-20.15) was an independent predictor of respiratory failure (PaO₂ /FiO₂ ratio < 300).

CONCLUSION

Soluble TM in BALF is an independent predictor of severe DLI. These findings underscore the importance of pulmonary endothelial injuries in the pathogenesis of severe DLI.