Prognostic Value of Serum Biomarkers in Patients with Idiopathic Pulmonary Fibrosis in Relation to Disease Progression

Lung Function Course of Patients With Pulmonary Fibrosis After Initiation of Anti-Fibrotic Treatment: Real-World Data From the Dutch National Registry

BACKGROUND AND OBJECTIVE

Real-world data on lung function course of patients with progressive pulmonary fibrosis (PPF) treated with anti-fibrotic medication are limited. We evaluated forced vital capacity (FVC) decline in patients with PPF and idiopathic pulmonary fibrosis (IPF) who started anti-fibrotic treatment.

METHODS

This was a nationwide multi-centre registry study in 16 hospitals throughout the Netherlands. Patients treated with anti-fibrotic medication, with at least two in-hospital pulmonary function tests before and after the initiation of anti-fibrotic treatment, were included. Linear mixed-effects modelling was used to analyse lung function trajectories 1 year before and after the start of anti-fibrotic treatment.

RESULTS

Data from 538 patients (n = 142 with PPF, n = 396 with IPF) were analysed. In PPF, the mean annualised FVC decline was 412 mL (95% confidence interval [CI]: 308-517 mL) before the initiation of anti-fibrotic treatment, and 18 mL (95% CI: 9-124 mL) in the first year after. The corresponding declines for IPF were 158 mL (95% CI: 78-239 mL) and 38 mL (95% CI: 24-101 mL). In both groups, treatment significantly slowed down FVC decline, although the change was larger in the PPF group (p = 0.0006). In the first year after treatment initiation, 28.0% of patients with PPF and 27.4% with IPF had disease progression.

CONCLUSION

The FVC decline significantly slowed after the initiation of treatment for both IPF and PPF. Nevertheless, a significant proportion of patients exhibited disease progression, despite the start of anti-fibrotic treatment. Early identification of these patients is crucial for treatment adaptations and inclusion in clinical trials.

Serum surfactant protein D as a significant biomarker for predicting occurrence, progression, acute exacerbation, and mortality in interstitial lung disease: a systematic review and meta-analysis

Objective

Serum surfactant protein D (SP-D) is a potential biomarker for the non-invasive prediction of interstitial lung disease (ILD) status. However, previous studies lacked comprehensively qualitative and quantitative pooled analysis methods to summarize the relationship between SP-D and ILD.

Methods

We conducted a comprehensive literature search from PubMed, Embase, Web of Science, Scopus, Ovid, and Cochrane Library, up to 16 December 2023. The Newcastle-Ottawa Quality Assessment Scale was employed to evaluate the quality of each included study. Pooled analyses were primarily performed for weighted mean difference (WMD), odds ratio (OR), and hazard ratio (HR). Sensitivity analysis was conducted by sequentially eliminating one study at a time and reanalyzing the remaining studies. In addition, the trim-and-fill method was applied for correcting publication bias.

Results

More than 3,561 patients with ILD from 41 articles were included for pooled analysis. The pooled results showed that serum SP-D levels were higher in the ILD group than the control group (WMD = 120.24 ng/mL, 95% CI: 72.45-168.03, p<0.001). Additionally, SP-D levels among patients with ILD were significantly elevated in the acute exacerbation (AE) group compared with the non-AE group (WMD = 9.88 ng/mL, 95% CI: 2.64-17.12, p=0.008), and in the death group compared with the survival group (WMD = 32.98 ng/mL, 95% CI: 2.11-63.84, p=0.036). However, no significant difference was observed between the progression group and the stable group (WMD = 13.54 ng/mL, 95% CI: -23.68-50.76, p=0.227). In addition, pooled results demonstrated that serum SP-D was a reliable predictive factor for various outcomes associated with ILD: occurrence (OR=4.66, 95%CI = 2.46, 8.86, p<0.001), progression (OR=1.003, 95%CI= 1.001, 1.006, p=0.033), and mortality (HR=1.002, 95%CI= 1.001, 1.003, p=0.023) of ILD. In contrast, there was no significant difference for predicting AE (HR = 1.004, 95% CI = 0.997, 1.011, p=0.240).

Conclusion

Serum SP-D is a significant biomarker associated with ILD occurrence, progression, acute exacerbation, and mortality. It remains essential to clarify the predictive value of serum SP-D levels concerning the disease status in patients with different ILD subtypes. Moreover, it may be beneficial to conduct a combined analysis of SP-D with other potential biomarkers to further enhance its diagnostic capability regarding the disease status in patients with ILD.

Systematic Review Registration

https://inplasy.com/inplasy-2024-5-0050/, identifier INPLASY 202450050.

Research progress of KL-6 in respiratory system diseases

This article comprehensively elucidates the discovery of Krebs von den Lungen-6 (KL-6), its structural features, functional mechanisms, and the current research status in various respiratory system diseases. Discovered in 1985, KL-6 was initially considered a tumor marker, but its elevated levels in interstitial lung disease (ILD) led to its recognition as a relevant serum marker for ILD. KL-6 is primarily produced by type 2 alveolar epithelial cell regeneration. Over the past 30 years since the discovery of KL-6, the number of related research papers has steadily increased annually. Following the coronavirus disease 2019 (COVID-19) pandemic, there has been a sudden surge in relevant literature. Despite KL-6's potential as a biomarker, its value in the diagnosis, treatment, and prognosis varies across different respiratory diseases, including ILD, idiopathic pulmonary fibrosis (IPF), COVID-19, and lung cancer. Therefore, as an important serum biomarker in respiratory system diseases, the value of KL-6 still requires further investigation.

Predictors of relapse of polymyositis/dermatomyositis associated interstitial lung disease

Background

Polymyositis/dermatomyositis (PM/DM) patients often develop interstitial lung disease (ILD), which can lead to relapse despite anti-inflammatory treatments. This study aims to elucidate the clinical characteristics of relapses in PM/DM-associated ILD patients.

Methods

We gathered clinical data, including laboratory results, pulmonary function tests, chest high-resolution computed tomography findings from patients treated at Okinawa Chubu Hospital between January 1, 2010 and December 31, 2018.

Results

We identified a total of 74 patients, comprising 21 men and 53 women. Among them, 38 patients remained relapse-free with maintenance therapy, while 36 experienced relapses despite immunosuppressive management. We followed these patients until June 30, 2023, and 13 patients died. The median survival period was 51.4 months (range, 0.3-214 months). When comparing clinical variables, relapsed patients tended to be younger (49.9 vs. 64.1 years), reported myalgia and rash more frequently (63.9% vs. 28.9% and 61.15% vs. 21.1%, respectively). In terms of laboratory findings, lactate dehydrogenase (LDH) levels were higher in relapsed patients (613±464 vs. 381±203 U/L). Radiological findings showed that ground glass opacity (GGO) was more prevalent in relapsed patients (58.3% vs. 16.7%). A Cox-proportional hazards model for relapse demonstrated that serum LDH [hazard ratio (HR) 1.005, 95% confidence interval (CI): 1.000-1.009, P=0.02] and GGO (HR 1.863, 95% CI: 1.103-3.147, P=0.02) were valuable predictors of relapse. Receiver operating characteristic curve analysis of serum LDH indicated that a threshold of 450 correctly classified relapse in PM/DM-associated ILD patients.

Conclusions

Serum LDH and GGO may serve as predictors of relapse in PM/DM-associated ILD patients.

Role of BAL and Serum Krebs von den Lungen-6 (KL-6) in Patients with Pulmonary Fibrosis

Background: Interstitial lung diseases (ILDs) encompass a diverse group of disorders affecting the lung interstitium, leading to inflammation, fibrosis, and impaired respiratory function. Currently, the identification of new diagnostic and prognostic biomarkers for ILDs turns out to be necessary. Several studies show the role of KL-6 in various types of interstitial lung disease and suggest that serum KL-6 levels can be used as a prognostic marker of disease. The aim of this study was to analyze KL-6 expression either in serum or bronchoalveolar lavage samples in order to: (i) make a serum vs. BAL comparison; (ii) better understand the local behavior of fibrosis vs. the systemic one; and (iii) evaluate any differences in patients with progressive fibrosis (PPF) versus patients with non-progressive fibrosis (nPPF). Methods: We used qRT-PCR to detect KL-6 expression both in serum and BAL samples. Mann-Whitney's U test was used to compare the differential expression between groups. Results: In serum, KL-6 is more highly expressed in PPF than in non-progressive fibrosis (p = 0.0295). This difference is even more significant in BAL (p < 0.001). Therefore, it is clear that KL-6 values are related to disease progression. Significant differences were found by making a comparison between BAL and serum. KL-6 was markedly higher in serum than BAL (p = 0.0146). Conclusions: This study identifies KL-6 as a promising biomarker for the severity of the fibrosing process and disease progression in ILDs, with significantly higher levels observed in PPF compared to nPPF. Moreover, the marked difference in KL-6 levels between serum and BAL emphasizes its potential diagnostic and prognostic relevance, providing enlightening insights into both the local and systemic aspects of ILDs.

Development of a Novel Biomarker for the Progression of Idiopathic Pulmonary Fibrosis

The progression of idiopathic pulmonary fibrosis (IPF) is diverse and unpredictable. We identified and validated a new biomarker for IPF progression. To identify a candidate gene to predict progression, we assessed differentially expressed genes in patients with advanced IPF compared with early IPF and controls in three lung sample cohorts. Candidate gene expression was confirmed using immunohistochemistry and Western blotting of lung tissue samples from an independent IPF clinical cohort. Biomarker potential was assessed using an enzyme-linked immunosorbent assay of serum samples from the retrospective validation cohort. We verified that the final candidate gene reflected the progression of IPF in a prospective validation cohort. In the RNA-seq comparative analysis of lung tissues, CD276, COL7A1, CTSB, GLI2, PIK3R2, PRAF2, IGF2BP3, and NUPR1 were up-regulated, and ADAMTS8 was down-regulated in the samples of advanced IPF. Only CTSB showed significant differences in expression based on Western blotting (n = 12; p < 0.001) and immunohistochemistry between the three groups of the independent IPF cohort. In the retrospective validation cohort (n = 78), serum CTSB levels were higher in the progressive group (n = 25) than in the control (n = 29, mean 7.37 ng/mL vs. 2.70 ng/mL, p < 0.001) and nonprogressive groups (n = 24, mean 7.37 ng/mL vs. 2.56 ng/mL, p < 0.001). In the prospective validation cohort (n = 129), serum CTSB levels were higher in the progressive group than in the nonprogressive group (mean 8.30 ng/mL vs. 3.00 ng/mL, p < 0.001). After adjusting for baseline FVC, we found that CTSB was independently associated with IPF progression (adjusted OR = 2.61, p < 0.001). Serum CTSB levels significantly predicted IPF progression (AUC = 0.944, p < 0.001). Serum CTSB level significantly distinguished the progression of IPF from the non-progression of IPF or healthy control.

Efficacy and Safety of Hydrogen Therapy in Patients with Early-Stage Interstitial Lung Disease: A Single-Center, Randomized, Parallel-Group Controlled Trial

Purpose

Several in vivo experiments have shown that molecular hydrogen is a promising therapeutic agent for interstitial lung diseases (ILD). In this study, hydrogen therapy was investigated to determine whether it is superior to N-Acetylcysteine (NAC) for the treatment of patients with early-stage ILD.

Patients and Methods

A prospective, single-center, randomized, controlled clinical trial was conducted in 87 patients with early-stage ILD. Hydrogen or NAC therapy was randomly assigned (1:1 ratio) to the eligible patients. The primary endpoint was the change in the high-resolution computed tomography (HRCT) and composite physiologic index (CPI) scores from baseline to week 48. Pulmonary function was evaluated as a secondary endpoint, and adverse events were recorded for safety analysis.

Results

The rate of HRCT image improvement from the baseline in the HW group (63.6%) was higher than that in the NAC group (39.5%). A significant decrease in CPI and improvement in DLCO-sb were observed in the hydrogen group compared with those in the control group. Changes in other pulmonary function parameters, including FVC, FEV1, FEV1/FVC%, and TLC, were not significantly different between the two groups. Adverse events were reported in 7 (15.9%) patients in the HW group and 10 (23.3%) patients in the NAC group, but the difference was not significant (P=0.706).

Conclusion

Hydrogen therapy exhibits superior efficacy and acceptable safety compared with NAC therapy in patients with early-stage ILD.