Serum KL-6 in fibrotic NSIP: Correlations with physiologic and radiologic parameters

Krebs von den Lungen-6 levels at admission predicts exercise-induced hypoxemia before and after discharge in patients with COVID-19

BACKGROUND

There are no reports of exercise-induced hypoxemia in patients with coronavirus disease 2019 (COVID-19). Additionally, the predictive factors and prevalence of exercise-induced hypoxemia are unknown. This study investigated the incidence and predictive factors of exercise-induced hypoxemia before and after discharge in patients with COVID-19.

METHODS

We enrolled 77 patients diagnosed with COVID-19 who were hospitalized between November 2020 and October 2021 and who underwent a 6-min walk test before and after discharge. Based on the test results, we classified patients into exercise-induced and non-exercise-induced hypoxemia groups and investigated the predictive factors of exercise-induced hypoxemia using logistic regression analysis.

RESULTS

The incidences of exercise-induced hypoxemia in patients with COVID-19 were 37.7% and 19.5% before and after discharge, respectively. At admission, the Krebs von den Lungen-6 levels was the associated factor for exercise-induced hypoxemia in patients with COVID-19 before and after discharge, with cut-off values of 314 U/mL and 367 U/mL, respectively. Age and lactate dehydrogenase levels were the associated factors for exercise-induced hypoxemia in patients with COVID-19 before discharge, with cut-off values of 61 years and 492 U/L, respectively.

CONCLUSIONS

Some patients with COVID-19 may continue to experience exercise-induced hypoxemia after discharge. Age, lactate dehydrogenase, and Krebs von den Lungen-6 levels at admission could serve as predictive markers of exercise-induced hypoxemia before and after discharge in these patients.

Characteristics of Interstitial Pneumonia With Autoimmune Features (IPAF): Protocol for a Multicenter Prospective Study

BACKGROUND

"Interstitial lung disease" (ILD) is a broad term encompassing diseases of different backgrounds. "Interstitial pneumonia with autoimmune features" (IPAF) is a recent term that implies the presence of autoimmunity.

OBJECTIVE

This study aims to determine the characteristics of Polish patients with IPAF, compare them with patients with other interstitial pneumonias, and search for the prognostic and diagnostic biomarkers of IPAF in serum and bronchoalveolar lavage fluid (BALF).

METHODS

This multicenter prospective study plans to recruit 240 participants divided into 1 study group and 2 control groups. Biological fluid samples will be collected according to Polish Respiratory Society management guidelines and stored at -80°C for further tests. Prospective 5-year observations of 60 newly diagnosed individuals are planned. The study will be divided into subsections. First, we plan to characterize Polish patients with IPAF (study group) against their peers with other ILDs (2 control groups). Control group 1 will comprise patients with idiopathic ILDs, including mainly idiopathic pulmonary fibrosis and nonspecific interstitial pneumonia. Control group 2 will comprise patients with connective tissue disease-associated interstitial lung diseases, such as rheumatoid arthritis, systemic sclerosis, polymyositis, dermatomyositis, Sjögren's syndrome, mixed connective tissue disease, and systemic lupus erythematosus. Radiological and functional parameters will be analyzed. Patients will be compared in terms of high-resolution computed tomography results, the 6-minute walking test performance, and pulmonary function test parameters. The diagnosis of IPAF will be reassessed on a regular basis through multidisciplinary discussion in order to determine its clinical stability. In the laboratory arm, inflammation and fibrosis pathways will be assessed. Cytokine levels (interleukin 8, transforming growth factor beta 1, chemokine C-C motif ligand [CXCL]18, CXCL1, surfactant protein [SP]-A, SP-D, Krebs von den Lungen-6 protein, and chitinase 1) will be measured in serum and BALF. A comparative analysis of serum and BALF cytokine levels will be performed in order to establish potential differences between systemic and local inflammatory pathways. In the quality of life (QoL) arm of the study, dyspnea and cough and their impact on various aspects of the QoL will be assessed. Depression and anxiety will be measured with the Hospital Anxiety and Depression Modified Scale and the 9-item Patient Health Questionnaire, and potential correlations with symptom prevalence will be assessed.

RESULTS

This study will start recruiting patients to phase 1 in October 2023. The final results will be available in 2028. We plan to publish preliminary results after 2-3 years from the start of phase 1.

CONCLUSIONS

This study will be a step toward a better understanding of IPAF etiopathogenesis and outcomes.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/44802.

Diagnosis of Fibrotic Hypersensitivity Pneumonitis: Is There a Role for Biomarkers?

Hypersensitivity pneumonitis is a complex interstitial lung syndrome and is associated with significant morbimortality, particularly for fibrotic disease. This condition is characterized by sensitization to a specific antigen, whose early identification is associated with improved outcomes. Biomarkers measure objectively biologic processes and may support clinical decisions. These tools evolved to play a crucial role in the diagnosis and management of a wide range of human diseases. This is not the case, however, with hypersensitivity pneumonitis, where there is still great room for research in the path to find consensual diagnostic biomarkers. Gaps in the current evidence include lack of validation, validation against healthy controls alone, small sampling and heterogeneity in diagnostic and classification criteria. Furthermore, discriminatory accuracy is currently limited by overlapping mechanisms of inflammation, damage and fibrogenesis between ILDs. Still, biomarkers such as BAL lymphocyte counts and specific serum IgGs made their way into clinical guidelines, while others including KL-6, SP-D, YKL-40 and apolipoproteins have shown promising results in leading centers and have potential to translate into daily practice. As research proceeds, it is expected that the emergence of novel categories of biomarkers will offer new and thriving tools that could complement those currently available.

KL-6 as a Biomarker of Interstitial Lung Disease Development in Patients with Sjögren Syndrome: A Retrospective Case–Control Study

Objective

Krebs von den Lungen-6 (KL-6) is expressed on regenerating type II pneumocytes and has been recognized as biomarkers in interstitial lung disease (ILD). We aim to identify the role of the serum KL-6 level in patients with newly diagnosed Sjögren syndrome (SS), as well as the correlation between the immunoassays.

Methods

Patients with newly diagnosed SS and receiving HRCT for clinical reason during follow-up were included. Baseline KL-6 level was measured via enzyme-linked immunosorbent assay (ELISA) and latex particle-enhanced turbidimetric immunoassay (LETIA).

Results

Of the 39 patients, 21 (53.85%) developed interstitial lung disease (ILD) by the conclusion of the follow-up period. The median time to diagnosis of ILD was 2.24 years (IQR 1.15–4.34) in the ILD group. The median serum KL-6 level, measured using ELISA, was 1232 U/mL (IQR 937–2242) and 764.5 U/mL (IQR 503.25–1035.75) in the ILD group and the non-ILD group, respectively (p = 0.001). The median LETIA for serum KL-6 was 329 U/mL (IQR 235–619) and 245 U/mL (IQR 215.25–291) in the ILD group and the non-ILD group, respectively (p = 0.074).

Conclusion

Serum KL-6 levels were higher in newly diagnosed SS patients with ILD diagnosis during follow-up. Thus, the serum KL-6 level can serve as a valuable biomarker to identify hidden ILD in patients with newly diagnosed SS patients. However, the immunoassay procedure may influence the efficacy of the prediction and its clinical association.

Comparison of Clinical Features between the High and Low Serum KL-6 Patients with Acute Exacerbation of Interstitial Lung Diseases

Background

Serum Krebs von den Lungen-6 (KL-6) measurement is widely used to assess disease activity or prognosis in patients with interstitial lung diseases (ILDs). However, the clinical differences between high and low serum KL-6 levels at the time of acute exacerbation (AE) of ILD are not well known.

Methods

Clinical parameters including age, sex, Charlson Comorbidity Index score (CCIS), blood biomarkers, high-resolution CT findings, and disease mortality were retrospectively compared between high and low KL-6 (cutoff value: 1000 U/mL) patients at the time of diagnosis of AE of ILDs.

Results

Thirty-eight high serum KL-6 and 57 low serum KL-6 patients were included. There was no significant difference in 6-month mortality between them (P = 0.685), whereas serum lactate dehydrogenase was a significant predictor of 6-month mortality in the high serum KL-6 patients (odds ratio (OR): 1.006; 95% confidence interval (CI): 1.003–1.009; P < 0.001), and CCIS (OR: 1.502; 95% CI: 1.242–1.838; P < 0.001) and sex (OR: 5.751; 95% CI: 1.121–105.163; P = 0.033) were significant predictors in low serum KL-6 patients. In addition, the incidences of congestive heart failure, symptomatic chronic pulmonary disease, cerebrovascular disease, and second metastatic solid tumours were significantly higher in nonsurvivors with low serum KL-6 than in other groups (P < 0.05).

Conclusions

The clinical features in patients with AEs of ILDs may differ depending on the serum KL-6 level, and clinicopathological examination according to this subtyping guided by the serum KL-6 level is essential.

The role of mucin 1 in respiratory diseases

Recent evidence has demonstrated that mucin 1 (MUC1) is involved in many pathological processes that occur in the lung. MUC1 is a transmembrane protein mainly expressed by epithelial and hematopoietic cells. It has a receptor-like structure, which can sense the external environment and activate intracellular signal transduction pathways through its cytoplasmic domain. The extracellular domain of MUC1 can be released to the external environment, thus acting as a decoy barrier to mucosal pathogens, as well as serving as a serum biomarker for the diagnosis and prognosis of several respiratory diseases such as lung cancer and interstitial lung diseases. Furthermore, bioactivated MUC1-cytoplasmic tail (CT) has been shown to act as an anti-inflammatory molecule in several airway infections and mediates the expression of anti-inflammatory genes in lung diseases such as chronic rhinosinusitis, chronic obstructive pulmonary disease and severe asthma. Bioactivated MUC1-CT has also been reported to interact with several effectors linked to cellular transformation, contributing to the progression of respiratory diseases such as lung cancer and pulmonary fibrosis. In this review, we summarise the current knowledge of MUC1 as a promising biomarker and drug target for lung disease.

Serum latent transforming growth factor-β binding protein 4 as a novel biomarker for idiopathic pleuroparenchymal fibroelastosis

BACKGROUND

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a rare idiopathic interstitial pneumonia characterized by an upper lobe-dominant interstitial increase in predominantly elastic fibers. The accumulation of cases has resulted in a refinement of the disease concept, but there are no blood biomarkers to aid in the diagnosis or prediction of a progressive phenotype among PPFE patients. Several organizers, including latent transforming growth factor-β binding protein 4 (LTBP-4), are known to be involved in elastogenesis. However, the potential of LTBP-4 as a blood biomarker for PPFE has not been investigated.

METHODS

We selected cases of clinically or histologically diagnosed IPPFE (n = 20) along with idiopathic pulmonary fibrosis (IPF) patients (n = 39) and healthy controls (n = 10). We quantified the protein levels of LTBP-4 in lung tissues and serum samples.

RESULTS

The LTBP-4 levels in lung tissue of PPFE patients were 2.16 times higher than those of IPF patients (p = 0.032). The serum concentration of LTBP-4 (pg/ml) in IPPFE was higher than that in healthy controls (1429 [154-3620] vs. 187 [56.4-490], p = 0.013). The serum concentration of LTBP-4 in IPPFE was markedly higher than that in IPF without a significant difference (1429 [154-3620] vs. 915 [491-1967], p = 0.671). In addition, a higher concentration of LTBP-4 was associated with a poor prognosis in IPPFE patients.

CONCLUSIONS

The serum concentration of LTBP-4 may aid in the diagnosis of IPPFE or the prediction of an aggressive phenotype.

Serum biomarker CA 15-3 as predictor of response to antifibrotic treatment and survival in idiopathic pulmonary fibrosis

Aim: Cancer antigen 15-3 (CA 15-3) is a baseline biomarker in idiopathic pulmonary fibrosis (IPF), but its value during follow-up is unknown. Materials and methods: Associations between serum CA 15-3 and pulmonary function tests during 1-year follow-up were evaluated by a mixed model in 132 IPF treated with pirfenidone or nintedanib. Results: Increased baseline (median: 56 kU/l) and follow-up CA 15-3 levels were inversely associated with forced vital capacity and diffusing capacity of the lung for carbon monoxide (estimates respectively: -5.21 and -4.69; p < 0.001). Baseline and 6-month CA 15-3 above 58.5 (hazard ratio: 1.67; p = 0.031) and 50.5 kU/l (hazard ratio: 2.99; p < 0.001), respectively, showed impaired survival compared with lower levels. Conclusion: CA 15-3 is associated with pulmonary function test during follow-up in IPF on antifibrotic treatment. Higher (follow-up) values are related with poor survival. Therefore, CA 15-3 is a promising follow-up biomarker in IPF.

Biomarkers and their potential functions in idiopathic pulmonary fibrosis

Introduction: Idiopathic pulmonary fibrosis (IPF) is a chronic, devastating, and progressive lung disease that is characterized by fibrosis and respiratory failure. IPF holds high morbidity and poor prognosis and still faces considerable problems of reliable diagnosis and valid prognosis. A growing body of literature have reported changes in the level of various biomarkers in IPF patients, which means that they are expected to become a new tool for the clinical practice of IPF.Areas covered: We reviewed the recent literature about biomarkers and focus on the role they play in IPF. We systematically searched Medline/PubMed through February 2020. Many works of literature have shown that a variety of biomolecules and genomics played multiple roles in the diagnosis or differential diagnosis, prognosis, and indication of acute deterioration of IPF and so on.Expert opinion: Significant advances have been made in the role of biomarkers for IPF these years; however, current data indicate that a single biomarker is unlikely to have a transformative effect on clinical practice; therefore, the combined effect of various biomarkers can be considered to improve the accuracy of diagnosis and prognosis. Further research of biomarkers may provide new insights for the diagnosis, prognosis, and even therapy of IPF.

Incidence and etiology of chronic pulmonary infections in patients with idiopathic pulmonary fibrosis

BACKGROUND

The incidence and etiologies of chronic pulmonary infection (CPI) in patients with idiopathic pulmonary fibrosis (IPF) have been poorly investigated.

METHODS

We conducted a retrospective study of 659 patients with IPF to assess the incidence, etiologies, and risk factors of CPI development. CPI was defined if the etiology of infection was diagnosed one or more months after the onset of symptoms or upon the appearance of new shadows on pulmonary radiological images.

RESULTS

At IPF diagnosis, 36 (5.5%) patients had CPI, and 46 (7.0%) patients without CPI at IPF diagnosis developed CPI over a median follow-up period of 6.1 years. The incidence density of CPI development was 18.90 cases per 1000 person-years. Detected organisms from these 46 patients were Mycobacterium avium complex in 20 patients, other nontuberculous mycobacteria in 4, M. tuberculosis in 7, Aspergillus spp. in 22, and Nocardia sp. in one. In a multivariate Cox regression hazard model, PaO2 <70 Torr and KL-6 ≥2000 U/mL were associated with CPI development.

CONCLUSIONS

Nontuberculous mycobacteria, M. tuberculosis, and Aspergillus and Nocardia spp. were the four most frequent etiologies of CPI in patients with IPF. During follow-up of IPF, clinicians should pay attention to the development of CPI, especially in patients with PaO2 <70 Torr or KL-6 ≥2000 U/mL.

Clinical Research on Prognostic Evaluation of Subjects With IPF by Peripheral Blood Biomarkers, Quantitative Imaging Characteristics and Pulmonary Function Parameters

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is an irreversible and progressive fatal interstitial lung disease with a poor prognosis. The aim of this study is to investigate the predictive value of combined blood biomarkers, pulmonary function and quantitative monitoring by computer-aided diagnosis (CAD) system in IPF patients.

METHODS

Pulmonary baseline function and pathological features of 126 patients with IPF were analyzed using spirometry and chest X-ray. Patients were divided into survival group and non-survival group after 5 years follow-up. The relationships the levels of peripheral blood biomarkers, quantitative imaging characteristics and pulmonary function were analyzed between the two groups.

RESULTS

The baseline level of serum Krebs von den Lungen-6 (KL-6) and C-X-C motif chemokine 13 (CXCL13) were moderately or highly correlated with annual changes in forced vital capacity (FVC), carbon monoxide diffusing capacity (DLCO), total lung capacity (TLC), total interstitial lung disease (ILD) lesions, and the volume changes of reticular. The baseline level of serum KL-6 was higher than the cut-off value of 800.0U/ml and baseline level of serum CXCL13 was higher than the cut-off value of 62.0pg/ml. IPF patients with baseline levels of serum KL-6 and CXCL13 lower than the cut-off value had longer median survival time.

CONCLUSIONS

Serum KL-6 and CXCL13 may be predictive biomarkers for the outcomes of patients with IPF patients and their baseline levels were related to the progression of pulmonary function and quantitative monitoring by CAD system.

Evaluation of the clinical performance of the HISCL-5000 analyzer in the detection of Krebs von den Lungen-6 antigen and its diagnostic value in interstitial lung disease

Background

The sputum saccharide chain antigen (Krebs von den Lungen‐6 [KL‐6]) is a serum biomarker of lung injury. We aimed to evaluate the clinical performance of the automated immunoassay analyzer HISCL‐5000 in detecting KL‐6 by comparing it with LUMIPULSE G1200 and determine the diagnostic value of KL‐6 in interstitial lung disease (ILD).

Methods

A total of 145 serum samples from patients were tested using the two automated immunoassay analyzers in parallel.

Results

With a cutoff level of 500 U/mL, comparing the two systems, the agreement, sensitivity, specificity, and kappa value were 99.20%, 100%, 98.63%, and 0.984 (95% CI, 0.952‐1.000), respectively. Spearman's correlation and ICC showed that there was a strong correlation between serum KL‐6 levels measured by the two systems (r_S = .991 [95% CI, 0.981‐0.995], ICC = 0.984 [95% CI, 0.978‐0.989], P < .01). The clinical diagnosis agreement rate in both systems was >80%. The kappa value was 0.707 (95% CI, 0.582‐0.832; SYSTEM B) and 0.707 (95% CI, 0.588‐0.826; SYSTEM A). The KL‐6 level in the ILD group (1339.5, 662.5‐2363) was significantly higher than that in the non‐ILD groups (252, 158.5‐353; Mann‐Whitney U = 381.5, P < .01), and the KL‐6 level (1558, 726‐2772.5) in the ILD group detected by SYSTEM A was significantly higher than that in the lung cancer group (339, 207‐424), other respiratory disease group (249, 194‐366), and control group (198, 131.5‐297; Kruskal‐Wallis H = 63.19, P < .01).

Conclusions

HISCL‐5000 showed well‐concordant results with those of HISCL‐5000 in the KL‐6 tests. In patients with ILD, KL‐6 showed a good diagnostic performance.

Evaluation of changes in the serum levels of Krebs von den Lungen-6 and surfactant protein-D over time as important biomarkers in idiopathic fibrotic nonspecific interstitial pneumonia

BACKGROUND

Some cases of idiopathic fibrotic nonspecific interstitial pneumonia (f-NSIP) show a progressive course that is similar to that of idiopathic pulmonary fibrosis. However, it is difficult to predict poor patient outcomes. This study aimed to evaluate whether serial changes in serum levels of Krebs von den Lungen-6 (KL-6) and surfactant protein-D (SP-D) can predict disease progression.

METHODS

We retrospectively analyzed the medical records of 75 patients with idiopathic f-NSIP. Disease behavior was categorized into two groups depending on long-term change of pulmonary function: progressive type (≥5%/year relative decline in the slope of forced vital capacity [FVC] and/or ≥7.5%/year relative decline in the slope of %diffusing capacity of the lung for carbon monoxide [%D_LCO]) and stable type. Levels of KL-6 and SP-D and results of pulmonary function tests, which were performed parallelly, were reviewed and analyzed using a linear mixed-effects model.

RESULTS

The study subjects comprised 62 patients with stable type and 13 patients with progressive type disease behavior. Among these subjects, 50 patients fulfilled the diagnostic criteria of interstitial pneumonia with autoimmune features (IPAF). Serum levels of both KL-6 and SP-D at baseline showed a negative correlation with %D_LCO, but not with FVC, and these biomarkers were not related to disease progression. Persistently high levels of KL-6 and SP-D correlated with progressive type disease behavior in idiopathic (non-IPAF) f-NSIP.

CONCLUSIONS

Changes in serum KL-6 and SP-D levels over time may provide useful predictive information on disease behavior during treatment in patients with idiopathic f-NSIP and especially in those with non-IPAF f-NSIP.

Serum KL-6 level is a prognostic marker in patients with anti-MDA5 antibody-positive dermatomyositis associated with interstitial lung disease

Objective

This study aimed to investigate the clinical significance of Krebs von den Lungen‐6 (KL‐6) serum levels in patients with anti‐MDA5 antibody‐positive dermatomyositis (anti‐MDA5⁺ DM) having interstitial lung disease (ILD), especially in the amyopathic DM phenotype.

Methods

The serum KL‐6 level was measured using a chemiluminescence enzyme immunoassay (CLEIA) in patients with anti‐MDA5⁺ DM, including clinically amyopathic dermatomyositis (CADM)‐ILD and classic DM‐ILD, and healthy donors. The baseline and post‐treatment serum KL‐6 levels were determined in 39 patients with CADM‐ILD who experienced remission or acute exacerbation. The association between laboratory findings, high‐resolution computed tomography (HRCT) scores, pulmonary function tests (PFTs), and the predictive value of baseline KL‐6 level for death was analyzed.

Results

The serum KL‐6 levels were significantly higher in patients with CADM‐ILD (1339 ± 1329 U/mL) compared with DM‐ILD (642.3 ± 498.4 U/mL) and healthy donors (162.4 ± 54.01 U/mL). The KL‐6 levels correlated positively with chest HRCT scores, serum lactate dehydrogenase, serum ferritin levels, and PFTs, but not with erythrocyte sedimentation rate. During follow‐up, the post‐treatment serum KL‐6 levels significantly reduced in the remission/stable group, but increased in the acute exacerbation group. Higher levels of ferritin and KL‐6 and HRCT scores were independently associated with poor prognosis. The 1‐year survival rate was significantly lower in patients with high KL‐6 level than in those with low KL‐6 level.

Conclusion

The serum KL‐6 levels may be a useful marker for predicting and monitoring ILD in Chinese patients with anti‐MDA5⁺ DM, especially amyopathic DM phenotype.

Analytical and Clinical Performance of the Nanopia Krebs von den Lungen 6 Assay in Korean Patients With Interstitial Lung Diseases

BACKGROUND

Krebs von den Lungen 6 (KL-6) is a sensitive marker for diagnosing, monitoring, and predicting the prognoses of interstitial lung diseases (ILDs). This study aimed to evaluate the performance of the Nanopia KL-6 assay (Sekisui Medical, Tokyo, Japan) and to test the relationship between KL-6 concentrations and clinical results.

METHODS

In total, 230 patients diagnosed as having ILDs were enrolled. All underwent high-resolution computed tomography (HRCT) followed by the pulmonary function test (PFT). We also enrolled 116 disease controls and 200 healthy controls. Evaluation of the Nanopia KL-6 assay involved determination of precision, linearity, and limit of quantification (LOQ). Results from the Nanopia KL-6 assay were compared with those from ELISA and correlated with the HRCT and PFT results.

RESULTS

The within-laboratory precisions were <2% of CV, and linearity was acceptable between 52.2 and 4,966.5 U/mL. The LOQ was 45.2 U/mL. Nanopia and ELISA results were strongly correlated (r=0.979). The average concentration of KL-6 was greater in ILD patients (711.5 U/mL) than in the disease (168.4 U/mL) and healthy (209.4 U/mL) controls. Serum KL-6 concentrations were strongly and moderately correlated with the extent of lung involvement and presence of typical HRCT abnormalities, respectively, and moderately correlated with PFT parameters.

CONCLUSIONS

The overall analytical and clinical performance of the Nanopia KL-6 assay was acceptable. Our study is the first to compare assay platforms and show correlations between KL-6 concentrations and HRCT or PFT results in Korean ILD patients.

A Fatal Case of Life-Threatening Interstitial Pneumonitis Induced by Everolimus for Metastatic Renal Cell Carcinoma: A Comment about the Increased Risk of Interstitial Lung Disease in Japanese

We describe an 81-year-old woman with metastatic renal cell carcinoma who did not recover from life-threatening interstitial pneumonitis induced by everolimus therapy. She received everolimus due to disease progression after sunitinib, but 2 months after starting everolimus treatment, she visited the emergency department after developing a sudden fever and dyspnea. Chest CT revealed diffuse ground-glass opacities, thickening of the interlobular septa, and consolidation throughout both lung fields. The diagnosis was surmised to be everolimus-induced interstitial pneumonitis. Everolimus administration was stopped and 3 courses of steroid pulse therapy were administered, along with intensive care, but the patient died due to rapid respiratory failure.

Drug-induced interstitial lung disease in the treatment of malignant lymphoma as a potential diagnostic marker: a comparison of serum Krebs von Lungen-6 and thymus and activation-regulated chemokine/CC chemokine ligand 17

Purpose

Cure-oriented treatment of malignant lymphoma (ML) is possible even in an advanced stage; however, the progression of drug-induced interstitial lung disease (DILD) sometimes accounts for poor clinical outcomes. This study aims to assess the incidence and clinical characteristics of DILD among patients with ML and compares the serum level of Krebs von den Lungen-6 (KL-6) with that of circulating thymus and activation-regulated chemokine (TARC)/CC chemokine ligand 17 (CCL17) as a diagnostic biomarker for DILD.

Patients and methods

Between July 2011 and August 2016, we enrolled 36 patients with ML who were undergoing systemic chemotherapy at our hospital. Then, we evaluated the serum concentration of KL-6 and TARC/CCL17 by a sandwich-type electrochemiluminescence immunoassay and enzyme-linked immunosorbent assay, respectively.

Results

DILD developed in 22.2% of patients with ML. All patients recovered immediately after the discontinuation of causative drug and/or glucocorticoid therapy. Although the sensitivity of both TARC/CCL17 and KL-6 was almost equal, the mean concentration of serum KL-6 after the progression of interstitial lung disease was significantly higher than that before progression.

Conclusion

DILD developed in patients who were treated with first-line rituximab combined regimen. Remarkably, TARC/CCL17 and KL-6 seemed approximately equal as a predictive biomarkers for DILD; however, KL-6 was more specific than TARC/CCL17.

Diagnostic value of KL-6 in idiopathic interstitial pneumonia

Background

Idiopathic interstitial pneumonia (IIP) can induce type II alveolar epithelial cell proliferation and pulmonary basement membrane damage and subsequent release of Krebs von den Lungen-6 antigen (KL-6) to the bloodstream. This study investigated the diagnostic and prognostic value of serum KL-6 levels for IIP.

Methods

One hundred five patients with lung disease were divided into IIP (n=75) and non-IIP groups (n=30) according to pathological and computed tomography findings. Serum KL-6 levels were evaluated in blood samples from all subjects. Nineteen IIP group patients were also subjected to a longitudinal study of disease progression and serum KL-6 levels over time.

Results

Serum KL-6 levels were significantly higher in the IIP group vs. the non-IIP group [1,096.0 (565.0-1,544.0) vs. 226.0 (173.5-346.5) U/mL; P<0.01]. Within the IIP group, serum KL-6 levels differed significantly between patients with and without concomitant disease or pulmonary infection (Z=-2.475, P=0.013). In a receiver operating characteristic (ROC) curve analysis, the area below the curve for serum KL-6 was 0.911 [95% confidence interval (CI): 0.847-0.975, P<0.001], indicating a good diagnostic performance for IIP, with a cut-off level of 485 U/mL, sensitivity of 85.33%, specificity of 90.00%, positive predictive value (PPV) of 95.52%, negative predictive value (NPV) of 71.05%, and Kappa value of 0.70. Accordingly, the serum KL-6 and clinical diagnostic results were consistent. Moreover, in the longitudinal study, the serum KL-6 levels differed significantly from before to after treatment in patients with exacerbated or improved disease (P=0.004 and P=0.043, respectively), whereas no obvious changes were observed in patients with stable disease (P=0.692).

Conclusions

The serum KL-6 level is a valuable and significant diagnostic marker of IIP and a useful predictor of clinical prognosis.

Serum surfactant protein D predicts the outcome of patients with idiopathic pulmonary fibrosis treated with pirfenidone

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a fatal pulmonary disease with poor prognosis. Pirfenidone, the first antifibrotic drug, suppresses the decline in forced vital capacity (FVC) and improves prognosis in some, but not all, patients with IPF; therefore, an indicator for identifying improved outcomes in pirfenidone therapy is desirable. This study aims to clarify whether baseline parameters can be predictors of disease progression and prognosis in patients with IPF treated with pirfenidone.

METHODS

We retrospectively investigated patients with IPF who started treatment with pirfenidone between December 2008 and November 2014 at the Sapporo Medical University Hospital. Patients treated with pirfenidone for ≥6 months were enrolled in this study and were observed until November 2015. We investigated the association of clinical characteristics, pulmonary function test results, and blood examination results at the start of pirfenidone with the outcome of patients.

RESULTS

Sixty patients were included in this study. In multivariate logistic regression analysis, % predicted FVC and serum surfactant protein (SP)-D levels were predictors of a ≥10% decline in FVC in the initial 12 months. In the Cox proportional hazards model, these two factors predicted progression-free survival. Pack-years, % predicted diffusing capacity for carbon monoxide, and SP-D levels predicted overall survival.

CONCLUSIONS

The serum SP-D level was a predictor of disease progression and prognosis in patients with IPF treated with pirfenidone. In addition, this analysis describes the relative usefulness of other clinical parameters at baseline in estimating the prognosis of patients with IPF who are candidates for pirfenidone therapy.

Serum KL-6 and surfactant protein-D as monitoring and predictive markers of interstitial lung disease in patients with systemic sclerosis and mixed connective tissue disease

BACKGROUND

Interstitial lung disease (ILD) is frequent complication of systemic sclerosis (SSc) and mixed connective tissue disease (MCTD). The disease is heterogeneous, and its outcome is unpredictable. Some patients have severe and progressive deterioration of ILD, which is the leading cause of mortality. We aimed to determine whether serum levels of Krebs von den Lungen-6 (KL-6) and surfactant protein-D (SP-D) correlate with SSc/MCTD-associated ILD activity.

METHODS

We retrospectively analyzed the medical records of 40 patients with SSc/MCTD-associated ILD: 29 patients with SSc and 11 patients with MCTD. Measurement of serum KL-6 and SP-D levels, pulmonary function tests, and high-resolution computed tomography (HRCT) performed in parallel were reviewed.

RESULTS

Serum KL-6 correlated positively with diffusing capacity of the lung for carbon monoxide (DLCO) (% predicted) and disease extent on HRCT, and the changes in serum levels of KL-6 were significantly related to the changes in forced vital capacity (FVC) in SSc/MCTD-associated ILD. On the other hand, multivariate logistic regression analyses with calculation of the area under the curve of the receiver-operating characteristic curve suggested that a higher serum level of SP-D was a significant predictor of FVC decline in SSc/MCTD-associated ILD.

CONCLUSIONS

Our study suggests that serum KL-6 can be a useful monitoring tool of SSc/MCTD-associated ILD activity. In contrast, serum SP-D may be a significant predictor of potential FVC decline in the short term.

Increased levels of prostaglandin E-major urinary metabolite (PGE-MUM) in chronic fibrosing interstitial pneumonia

BACKGROUND

Dysregulation of the prostaglandin E2 (PGE2) signaling pathway has been implicated in interstitial pneumonia (IP) pathogenesis. Due to the unstable nature of PGE2, available detection methods may not precisely reflect PGE2 levels. We explored the clinical usefulness of measuring stable prostaglandin E-major urinary metabolite (PGE-MUM) with respect to pathogenesis and extent of chronic fibrosing IP (CFIP), including idiopathic pulmonary fibrosis (IPF), as PGE-MUM is reflective of systemic PGE2 production.

METHODS

PGE-MUM was measured by radioimmunoassay in controls (n = 124) and patients with lung diseases (bronchial asthma (BA): n = 78, chronic obstructive pulmonary disease (COPD): n = 33, CFIP: n = 44). Extent of lung fibrosis was assessed by fibrosing score (FS) of computed tomography (CT) (FS1-4). Immunohistochemical evaluation of COX-2 was performed to find PGE2 producing cells in IPF. Human bronchial epithelial cells (HBEC) and lung fibroblasts (LFB) were used in in vitro experiments.

RESULTS

Compared to control, PGE-MUM levels were significantly elevated in CFIP. PGE-MUM levels were positively correlated with FS, and inversely correlated with %DLCO in IP (FS 1-3). COX-2 was highly expressed in metaplastic epithelial cells in IPF, but lower expression of EP2 receptor was demonstrated in LFB derived from IPF. TGF-β induced COX-2 expression in HBEC.

CONCLUSIONS

PGE-MUM, elevated in CFIP, is a promising biomarker reflecting disease activity. Metaplastic epithelial cells can be a source of elevated PGE-MUM in IPF.

Prognostic value of serial serum KL-6 measurements in patients with idiopathic pulmonary fibrosis

BACKGROUND

The prognostic significance of serial measurements of serum KL-6 levels in patients with idiopathic pulmonary fibrosis (IPF) is unclear; hence, it was assessed in this study.

METHODS

Medical records of 66 patients with IPF, who were not treated with pirfenidone prior to enrollment, were retrospectively reviewed for information on clinical progress, forced vital capacity (FVC), survival, and serum KL-6 levels. We assessed initial serum levels of KL-6, serial changes in serum KL-6 levels, yearly decline in FVC (ΔFVC), and the rate of decline (%ΔFVC).

RESULTS

Patients with increased serum KL-6 levels during follow-up had a significantly steeper decline in ΔFVC than those with no KL-6 increase (-201 vs. -50.7ml/year; p=0.0001). Patients with both initial serum KL-6 ≥1000U/ml and serial increases in serum KL-6 had the steepest decline, while those with both initial serum KL-6 <1000ml and no serial increases in KL-6 had the least decline in ΔFVC and %ΔFVC. Relative to the non-increased KL-6 group, survival in the increased KL-6 group tended to be poorer (p=0.0530). Patients with both initial serum KL-6 values <1000U/ml and no serial increase in KL-6 had more favorable prognoses than those with serial increases in KL-6 or initial serum KL-6 values ≥1000U/ml (p<0.0044). Prognosis was significantly poorer in patients with serial KL-6 changes >51.8U/ml/year than in those with serial KL-6 changes <51.8U/ml/year (p=0.0009).

CONCLUSION

Thus, serial serum KL-6 measurements can be useful for assessing prognosis in patients with IPF.

Interstitial lung disease in clinically amyopathic dermatomyositis with and without anti-MDA-5 antibody: to lump or split?

Background

Interstitial lung disease (ILD) associated with clinically amyopathic dermatomyositis (CADM-ILD) is often refractory and rapidly progressive. Although the anti-melanoma differentiation-associated gene 5 (anti-MDA-5) antibody is associated with rapidly progressive ILD (RP-ILD), differences in clinical features and prognosis of anti-MDA-5 antibody-positive and -negative CADM-ILD remain unclear.

Methods

To clarify the differences in the clinical features and prognosis between anti-MDA-5 antibody-positive and -negative cases, we retrospectively reviewed the medical records of patients diagnosed with CADM-ILD with and without anti-MDA-5 antibody at Kurashiki Central Hospital from January 2005 to September 2014.

Results

Anti-MDA-5 antibody was found in 10 of 16 patients (63 %). The levels of Krebs von den Lungen-6 (KL-6) and surfactant protein D (SP-D) at the first visit were significantly lower in positive patients than in negative patients, whereas the levels of aspartate aminotransferase (AST), γ-glutamyl transpeptidase (γ-GTP), and the CD4⁺/CD8⁺ ratio in the bronchoalveolar lavage (BAL) fluid were significantly higher in positive patients than negative patients. Subpleural ground-glass opacity (GGO) or irregular linear opacity was predominant in positive patients. Peribronchovascular consolidation was predominant in negative patients. Positive patients had significantly lower survival rates than negative patients, with all six fatal cases occurring in positive patients who died of refractory ILD within 92 days from the first visit despite intensive treatment.

Conclusions

There are clear differences in the clinical features and prognosis of anti-MDA-5 antibody-positive and -negative CADM-ILD. Low serum KL-6 and SP-D levels, high serum AST and γ-GTP levels, high CD4⁺/CD8⁺ ratio in BAL fluid, and predominance of subpleural GGO or irregular linear opacity in HRCT may help to discriminate anti-MDA-5 antibody-positive CADM-ILD with poor prognosis.

Circulating thymus and activation-regulated chemokine/CC chemokine ligand 17 is a strong candidate diagnostic marker for interstitial lung disease in patients with malignant tumors: a result from a pilot study

Introduction

Serum Krebs von den Lungen-6 (KL-6) level is an established diagnostic marker of interstitial lung disease (ILD). However, it is also elevated in patients with non-small cell lung cancer (NSCLC). The significance of circulating thymus and activation-regulated chemokine (TARC)/CC chemokine ligand 17 (CCL17) in malignant diseases remains unknown.

Methods

We measured circulating TARC/CCL17 and KL-6 using enzyme-linked immunosorbent assay and electrochemiluminescence immunoassay, respectively, in 26 patients with malignant disease and six patients with benign lung disease (BLD). The cutoff levels were 500 U/mL for KL-6 and 450 pg/mL for TARC/CCL17. The significance of the markers was evaluated in relationship to the presence of ILD (n=10). The statistical significance was set at P<0.05.

Results

The KL-6 positive ratio was significantly higher in the patients with NSCLC (n=17) than in those with BLD. There was a significant difference in the KL-6 positive ratio between the patients with NSCLC without ILD and those with BLD without ILD. However, there were no significant differences in the TARC/CCL17 positive ratio between the patients with NSCLC and BLD or between those with NSCLC without ILD and those with BLD without ILD. The TARC/CCL17 positive ratio was significantly higher in the patients with malignancy and ILD than in those without ILD. There was also a significant difference in the TARC/CCL17 positive ratio between the patients with NSCLC without ILD and those with ILD.

Conclusion

TARC/CCL17 may be useful for the diagnosis of ILD in patients with malignancies. Confirmation of the results is warranted through a large-scale study.

Effects of molecular structural variants on serum Krebs von den Lungen-6 levels in sarcoidosis

BACKGROUND

Serum Krebs von den Lungen-6 (KL-6), which is classified as human mucin-1 (MUC1), is used as a marker of sarcoidosis and other interstitial lung diseases. However, there remain some limitations due to a lack of information on the factors contributing to increased levels of serum KL-6. This study was designed to investigate the factors contributing to increased levels of serum KL-6 by molecular analysis.

METHODS

Western blot analysis using anti-KL-6 antibody was performed simultaneously on the bronchoalveolar lavage fluid (BALF) and serum obtained from 128 subjects with sarcoidosis.

RESULTS

KL-6/MUC1 in BALF showed three bands and five band patterns. These band patterns were associated with the MUC1 genotype and the KL-6 levels. KL-6/MUC1 band patterns in serum were dependent on molecular size class in BALF. Significantly increased levels of serum KL-6, serum/BALF KL-6 ratio and serum soluble interleukin 2 receptor were observed in the subjects with influx of high molecular size KL-6/MUC1 from the alveoli to blood circulation. The multivariate linear regression analysis involving potentially relevant variables such as age, gender, smoking status, lung parenchymal involvement based on radiographical stage and molecular size of KL-6/MUC1 in serum showed that the molecular size of KL-6/MUC1 in serum was significant independent determinant of serum KL-6 levels.

CONCLUSIONS

The molecular structural variants of KL-6/MUC1 and its leakage behavior affect serum levels of KL-6 in sarcoidosis. This information may assist in the interpretation of serum KL-6 levels in sarcoidosis.

Utility of KL-6/MUC1 in the clinical management of interstitial lung diseases

Interstitial lung diseases (ILDs) are a diverse group of pulmonary disorders characterized by various patterns of inflammation and fibrosis in the interstitium of the lung. Because injury and/or regeneration of type II pneumocytes are prominent histological features of ILDs, substances derived from type II pneumocytes have been the focus of research investigating potential biomarkers for ILD. One important biomarker for ILD is the high-molecular-weight glycoprotein, Krebs von den Lungen-6 (KL-6). KL-6 is now classified as a human MUC1 mucin protein, and regenerating type II pneumocytes are the primary cellular source of KL-6/MUC1 in the affected lungs of patients with ILD. KL-6/MUC1 is detectable in the serum of patients with ILD, and extensive investigations performed primarily in Japan have revealed that serum KL-6/MUC1 is elevated in 70-100% of patients with various ILDs, including idiopathic interstitial pneumonias, collagen vascular disease-associated interstitial pneumonia, hypersensitivity pneumonia, radiation pneumonitis, drug-induced ILDs, acute respiratory distress syndrome, pulmonary sarcoidosis, and pulmonary alveolar proteinosis. The results from these various studies have supported the utility of KL-6/MUC1 as a serum biomarker for detecting these various ILDs. Moreover, KL-6/MUC1 serum levels have been demonstrated to be useful for evaluating disease activity and predicting the clinical outcomes of various ILD types. Based on these observations, we believe that KL-6/MUC1 is currently one of the best and most reliable serum biomarkers available for ILD management.

The Diagnostic Value of the Interstitial Biomarkers KL-6 and SP-D for the Degree of Fibrosis in Combined Pulmonary Fibrosis and Emphysema

The combined pulmonary fibrosis and emphysema (CPFE) was reported first in 1990, but it has been comparatively underestimated until recently. Although the diagnostic findings of both emphysematous and fibrotic regions are detectable by high-resolution computed tomography (HRCT) of the chest, the degree of progressive fibrosis, which increases with emphysematous lesions, is difficult to evaluate. In this study, we hypothesized that the biomarkers for pulmonary fibrosis, surfactant protein D (SP-D), and KL-6 would serve as good indicators of fibrotic lesions in CPFE. We recruited 46 patients who had been diagnosed in our hospital with both emphysema and fibrosis by their CT scan image from April 2003 to March 2008. The correlation among their pulmonary function tests, composite physiologic index (CPI), and the serum levels of SP-D and KL-6 was evaluated. We found a correlation between KL-6 and %VC, %TLC, or CPI and between SP-D and %VC or CPI. Interestingly, the combined product of KL-6 and SP-D (KL-6xSP-D) was found to highly correlate with %VC and %TLC or CPI. These results show that both KL-6 and SP-D, and especially the product of SP-D and KL-6, are good indicators of the presence of fibrotic lesions in the lungs of CPFE patients.

Acute exacerbation of idiopathic pulmonary fibrosis: high-resolution CT scores predict mortality

OBJECTIVES

To determine high-resolution computed tomography (HRCT) findings helpful in predicting mortality in patients with acute exacerbation of idiopathic pulmonary fibrosis (AEx-IPF).

METHODS

Sixty patients with diagnosis of AEx-IPF were reviewed retrospectively. Two groups (two observers each) independently evaluated pattern, distribution, and extent of HRCT findings at presentation and calculated an HRCT score at AEx based on normal attenuation areas and extent of abnormalities, such as areas of ground-glass attenuation and/or consolidation with or without traction bronchiectasis or bronchiolectasis and areas of honeycombing. The correlation between the clinical data including the HRCT score and mortality (cause-specific survival) was evaluated using the univariate and multivariate Cox-regression analyses.

RESULTS

Serum KL-6 level, PaCO(2), and the HRCT score were statistically significant predictors on univariate analysis. Multivariate analysis revealed that the HRCT score was an independently significant predictor of outcome (hazard ratio, 1.13; 95% confidence interval, 1.06-1.19, P = 0.0002). The area under receiver operating characteristics curve for the HRCT score was statistically significant in the classification of survivors or nonsurvivors (0.944; P < 0.0001). Survival in patients with HRCT score ≥245 was worse than those with lower score (log-rank test, P < 0.0001).

CONCLUSION

The HRCT score at AEx is independently related to prognosis in patients with AEx-IPF.