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Vasohibin-1 (VASH-1) is a potent anti-angiogenic factor mainly produced by endothelial cells. In addition, VASH-1 prevents TGF-β-dependent activation of renal fibroblasts. Since systemic sclerosis (SSc) is an autoimmune disease characterized by vasculopathy and fibrosis of multiple organs, VASH-1 may be involved in the development of this disease. In this study, we investigated the potential role of VASH-1 in SSc by evaluating the clinical correlation between serum VASH-1 levels and the expression of VASH-1 in SSc-involved skin. Serum VASH-1 levels were higher in SSc patients, especially those with diffuse cutaneous involvement, than in healthy controls and positively correlated with skin score. Furthermore, SSc patients with interstitial lung disease had significantly elevated levels of serum VASH-1 as compared to those without. Importantly, serum VASH-1 levels correlated inversely with both the percentage of predicted vital capacity and the percentage of predicted diffusion lung capacity for carbon monoxide and positively with serum KL-6 levels, but not serum surfactant protein D levels. In SSc-involved skin, VASH1 mRNA was remarkably upregulated compared with healthy control skin, but the major source of VASH-1 was not clear. Fli1 deficiency, a predisposing factor inducing SSc-like endothelial properties, did not affect VASH-1 expression in human dermal microvascular endothelial cells. Collectively, these results suggest that VASH-1 upregulation in the skin and sera is linked to dermal and pulmonary fibrotic changes in SSc, while the contribution of VASH-1 to SSc vasculopathy seems to be limited., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: MUC1 (MUC in human and Muc in animals) is a membrane-tethered mucin expressed on the apical surface of lung epithelial cells. However, in the lungs of patients with interstitial lung disease, MUC1 is aberrantly expressed in hyperplastic alveolar type II epithelial (ATII) cells and alveolar macrophages (AM), and elevated levels of extracellular MUC1 are found in bronchoalveolar lavage (BAL) fluid and the serum of these patients. While pro-fibrotic effects of extracellular MUC1 have recently been described in cultured fibroblasts, the contribution of MUC1 to the pathobiology of pulmonary fibrosis is unknown. In this study, we hypothesized that MUC1 deficiency would reduce susceptibility to pulmonary fibrosis in a mouse model of silicosis., Methods: We employed human MUC1 transgenic mice, Muc1 deficient mice and wild-type mice on C57BL/6 background in these studies. Some mice received a one-time dose of crystalline silica instilled into their oropharynx in order to induce pulmonary fibrosis and assess the effects of Muc1 deficiency on fibrotic and inflammatory responses in the lung., Results: As previously described in other mouse models of pulmonary fibrosis, we found that extracellular MUC1 levels were markedly increased in whole lung tissues, BALF and serum of human MUC1 transgenic mice after silica. We also detected an increase in total MUC1 levels in the lungs of these mice, indicating that production as well as release contributed to elevated levels after lung injury. Immunohistochemical staining revealed that increased MUC1 expression was mostly confined to ATII cells and AMs in areas of fibrotic remodeling, illustrating a pattern similar to the expression of MUC1 in human fibrotic lung tissues. However, contrary to our hypothesis, we found that Muc1 deficiency resulted in a worsening of fibrotic remodeling in the mouse lung as judged by an increase in number of silicotic nodules, an increase in lung collagen deposition and an increase in the severity of pulmonary inflammation., Conclusions: Altogether, our results indicate that Muc1 has anti-fibrotic properties in the mouse lung and suggest that elevated levels of MUC1 in patients with interstitial lung disease may serve a protective role, which aims to limit the severity of tissue remodeling in the lung., (Copyright © 2017. Published by Elsevier Inc.)

Background: We have seen cases of chronic interstitial pneumonia (IP) with pulmonary alveolar proteinosis (PAP)-like changes that are focal histological features similar to PAP. To our knowledge, the association between PAP-like changes and chronic IP has not been investigated. We aimed to evaluate the incidence of PAP-like changes in chronic IP cases, and the association between the existence of PAP-like changes and the clinical features seen in patients with idiopathic pulmonary fibrosis (IPF)., Methods: We selected 144 cases of chronic IP that had a video-assisted thoracoscopic surgery biopsy between 2008 and 2011. Clinical records and hematoxylin and eosin-stained slides were reviewed, and clinicopathological findings, including the cumulative survival probability, were compared between IPF cases with and without a PAP-like change., Results: A PAP-like change was identified in 20 of 144 cases (13.9%) of chronic IP and 14 of 61 IPF cases (23.0%). When comparing IPF cases with and without a PAP-like change, histological findings of honeycomb cysts and fibroblastic foci were associated with PAP-like changes (p=0.022 and 0.036, respectively). The percent-predicted values for forced vital capacity and diffusion capacity of carbon monoxide were lower (p=0.006 and 0.015, respectively), and concentrations of serum Krebs von den Lungen-6 and lactate dehydrogenase were higher (p=0.007 and 0.037, respectively) in cases of IPF with a PAP-like change than in those without one., Conclusions: The presence of a PAP-like change in IPF cases was fairly common in our study, and may be a secondary reaction associated with IPF severity., (Copyright © 2016. Published by Elsevier B.V.)

Multi-walled carbon nanotubes (MWCNT) with their unique physico-chemical properties offer numerous technological advantages and are projected to drive the next generation of manufacturing growth. As MWCNT have already found utility in different industries including construction, engineering, energy production, space exploration and biomedicine, large quantities of MWCNT may reach the environment and inadvertently lead to human exposure. This necessitates the urgent assessment of their potential health effects in humans. The current study was carried out at NanotechCenter Ltd. Enterprise (Tambov, Russia) where large-scale manufacturing of MWCNT along with relatively high occupational exposure levels was reported. The goal of this small cross-sectional study was to evaluate potential biomarkers during occupational exposure to MWCNT. All air samples were collected at the workplaces from both specific areas and personal breathing zones using filter-based devices to quantitate elemental carbon and perform particle analysis by TEM. Biological fluids of nasal lavage, induced sputum and blood serum were obtained from MWCNT-exposed and non-exposed workers for assessment of inflammatory and fibrotic markers. It was found that exposure to MWCNTs caused significant increase in IL-1β, IL6, TNF-α, inflammatory cytokines and KL-6, a serological biomarker for interstitial lung disease in collected sputum samples. Moreover, the level of TGF-β1 was increased in serum obtained from young exposed workers. Overall, the results from this study revealed accumulation of inflammatory and fibrotic biomarkers in biofluids of workers manufacturing MWCNTs. Therefore, the biomarkers analyzed should be considered for the assessment of health effects of occupational exposure to MWCNT in cross-sectional epidemiological studies., (Published by Elsevier Inc.)

In forensic cases, detailed identification of pneumonia is important. Our objective was to statistically determine the applicability of three interstitial lung disease (ILD) markers for forensic diagnosis using serum collected from dead bodies with various postmortem intervals (PMIs). We retrospectively analyzed the levels of postmortem serum Krebs von den Lungen-6 (KL-6) and pulmonary surfactant–associated proteins A and D (SP-A and SP-D) using 221 samples obtained during forensic autopsy at our facility from 2019 to 2023. We evaluated the diagnostic efficacy of ILD markers for various pneumonias against the pathological diagnosis, and examined the assessment of the severity of ILD. When comparing the ILD group with bacterial pneumonia (BP) versus the control group, there was a significant increase in KL-6 in the ILD group. When comparing the severe ILD (SILD) group with the mild ILD (MILD) group, there was a significant increase in KL-6 and SP-D in the SILD group. The optimal cutoff values for differentiating SILD were 607.0 U/mL for KL-6, 55.5 ng/mL for SP-A, and 160.0 ng/mL for SP-D, and the sensitivity/specificity (%) of KL-6, SP-A, and SP-D for SILD were 84.1/95.2, 55.6/85.7, and 66.7/74.6, respectively. This is the first study to examine KL-6 in postmortem serum in forensic medicine. By analyzing dead bodies with various PMIs, our results confirmed statistically that postmortem serum KL-6 specifically detects ILD, postmortem serum SP-A has high sensitivity to lung injury, and postmortem serum SP-D is potentially useful in assessing the severity of ILD. [ABSTRACT FROM AUTHOR]

Background: Dermatomyositis (DM) is a rare inflammatory disease. Our research focuses on predicting poor prognosis in DM patients and evaluating the prognostic significance of ferritin and Salivary Sugar Chain Antigen‐6 (KL‐6) through multivariate logistic regression analysis. Methods: Between February 2018 and April 2020, 80 DM patients at our hospital were categorized into MDA5 positive (n = 20) and negative (n = 60) groups. We conducted multivariate logistic regression to determine DM's poor prognosis risk factors and evaluate ferritin/KL‐6′s predictive value for prognosis. Results: Analysis showed no gender, age, body mass index (BMI), or lifestyle (smoking, drinking) differences, nor in dyspnea, muscle weakness, skin ulcers, and acetylcysteine treatment effects (p > 0.05). Significant differences emerged in arrhythmias, interstitial pneumonia, C‐reactive protein, albumin, and lactate dehydrogenase levels (p < 0.05). Before treatment, differences were negligible (p > 0.05), but post‐treatment, serum KL‐6 and ferritin levels dropped. MDA5 positive patients had elevated serum KL‐6 and ferritin levels than survivors (p < 0.05), with a strong correlation to DM. Combined diagnosis using serum KL‐6 and ferritin for DM prognosis showed area under curves of 0.716 and 0.634, significantly outperforming single‐index diagnoses with an area under curve (AUC) of 0.926 (p < 0.05). Conclusion: Serum KL‐6 and ferritin show marked abnormalities in DM, useful as indicators for evaluating polymyositis and DM conditions. However, the study's small sample size is a drawback. Expanding the sample size is essential to monitor serum KL‐6 and ferritin changes in DM patients under treatment more closely, aiming to improve clinical assessment and facilitate detailed research. [ABSTRACT FROM AUTHOR]

Background: The serum level of Krebs von den Lungen-6 (sKL-6) is a biomarker of interstitial pneumonia and has been reported to be elevated in patients with cancers. However, there have been few cases of gastric cancer (GC) with elevated sKL-6 that were treated by chemotherapy. We herein report two cases of GC with elevated sKL-6 that were treated with oxaliplatin plus S-1 (SOX) chemotherapy and discussed the resulting changes in sKL-6. Case presentation: The first patient was a 79-year-old woman complaining of loss of appetite. Esophagogastroduodenoscopy (EGD) showed a type-3 tumor in the gastric antrum and biopsy specimens showed adenocarcinoma. Computed tomography (CT) showed multiple liver metastases. sKL-6 was elevated to 1,292 U/ml, but a CT revealed no obvious lesions of the lungs, including interstitial pneumonia. The tumor was diagnosed as GC with liver metastases and elevated sKL-6. Respiratory function data were normal. SOX therapy using oxaliplatin and S-1 was performed. After 3 courses of SOX therapy, CT showed reductions of the liver metastases as well as the primary tumor, and sKL-6 was decreased to 201 U/ml. After the 44 courses, sKL-6 was slightly elevated. Chest CT showed interstitial pneumonia and chemotherapy was stopped. The patient is still alive without any metastasis 72 months later. The second patient was a 69-year-old woman complaining of upper abdominal pain. EGD revealed a type-3 tumor in the gastric antrum showing adenocarcinoma with HER2-positive pathology. CT showed multiple node metastases around the abdominal aorta. sKL-6 was elevated to 2,239 U/ml, but a respiratory function test showed no abnormalities, and CT of the lungs showed no obvious lesions. The tumor was diagnosed as GC with distant node metastases and elevated sKL-6. The patient received SOX therapy combined with trastuzumab. After 6 courses, the size of the primary tumor and multiple node metastases were reduced, and sKL-6 was decreased to 284 U/ml. Conclusions: These two cases suggest that sKL-6 may be important not only as an indicator of interstitial pneumonia in chemotherapeutic courses, but also as a tumor marker in GC patients with multiple metastases. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2)-infection is associated with an extremely variable disease course. When interstitial pneumonia (IP) occurs, it can lead to acute respiratory distress syndrome and death. Serum Krebs von den Lungen-6 (KL-6) is an established marker of IP, but its role as a marker of SARS-CoV-2 pneumonia is debated. This bicentric study included 157 patients with SARS-CoV-2 pneumonia. The WHO Ordinal Scale for Clinical Improvement (0–10 points) was used to classify the clinical course. Serum samples were collected at admission, and on days 3 and 7 of hospitalization. KL-6 was measured by using automated chemiluminescence immunoassay. A total of 68 patients developed a severe SARS-CoV-2 pneumonia, 135 of them required oxygen, and 15 died during hospitalization. The patients requiring non-invasive ventilation, invasive ventilation, or extracorporeal membrane oxygenation had significantly higher serum KL-6 levels at admission. The serum KL-6 levels were tendentially higher in patients who died than in those who survived. Logistic regression identified serum KL-6 at a cut-off of 335 U/mL at admission as a significant predictor of severe SARS-CoV-2 pneumonia outcome. Serum KL-6 seems to be a candidate biomarker for the clinical routine to stratify patients with SARS-CoV-2 pneumonia for the risk of a severe disease outcome or death. [ABSTRACT FROM AUTHOR]

The development of a progressive phenotype of interstitial lung disease (ILD) is still unpredictable. Whereas tools to predict mortality in ILD exist, scores to predict disease progression are missing. The aim of this study was to investigate whether baseline serum KL-6 as an established marker to assess disease activity in ILD, alone or in combination with clinical variables, could improve stratification of ILD patients according to progression risk at any time. Consecutive patients with fibrotic ILD, followed at our institution between 2008 and 2015, were investigated. Disease progression was defined as relative decline of ≥10% in forced vital capacity (FVC) or ≥15% in diffusing capacity of the lung for carbon monoxide (DLco)% from baseline at any time. Serum KL-6 was measured using an automated immunoassay (Fujirebio Europe, Gent, Belgium). A stepwise logistic regression was performed to select variables to be included in the score. A total of 205 patients (49% idiopathic pulmonary fibrosis (IPF), 51% fibrotic nonspecific interstitial pneumonia (NSIP)) were included, of them 113 (55%) developed disease progression during follow up. Male gender (G) and serum KL-6 strata (K) were significant predictors of progression at regression analysis and were included in the GK score. A threshold of 2 GK score points was best for discriminating patients at high risk versus low risk to develop disease progression at any time. Serum KL-6 concentration, alone or combined in a simple score with gender, allows an effective stratification of ILD patients for risk of disease progression at any time. [ABSTRACT FROM AUTHOR]

Presepsin is an early indicator of infection, and Krebs von den Lungen 6 (KL-6) and Surfactant Protein A (SP-A) are related to the pathogenesis of pulmonary infection and fibrosis. This study aimed to establish reference intervals (RIs) of presepsin, KL-6, and SP-A levels and to evaluate the possible influence of neonatal and maternal factors on presepsin, KL-6, and SP-A levels in umbilical cord blood (UCB). Among a total of 613 UCB samples, the outliers were removed. The RIs for presepsin, KL-6, and SP-A levels were defined using non-parametric percentile methods according to the Clinical and Laboratory Standards Institute guidelines (EP28-A3C). These levels were analyzed according to neonatal and maternal factors: neonatal sex, gestational age (GA), birth weight (BW), Apgar score, delivery mode, the presence of premature rupture of membranes (PROM), gestational diabetes mellitus (GDM), and pre-eclampsia. Presepsin, KL-6, and SP-A levels showed non-parametric distributions and left-skewed histograms. The RIs of presepsin, KL-6, and SP-A levels were 64.9–428.3 pg/mL, 43.0–172.0 U/mL, and 2.1–36.1 ng/mL, respectively. Presepsin, KL-6, and SP-A levels did not show significant differences according to sex, GA, BW, Apgar score, delivery mode, PROM, GDM, and pre-eclampsia. The median level and 97.5th centile RI of KL-6 showed a slight increase with increased GA. We established RIs for presepsin, KL-6, and SP-A levels in large-scaled UCB samples. Further investigation would be needed to determine the clinical significance. [ABSTRACT FROM AUTHOR]

Idiopathic pulmonary fibrosis (IPF) and non-specific interstitial pneumonia (NSIP) are the most frequent idiopathic interstitial pneumonias. The aim of this study was to evaluate concentrations of calgranulin B and Krebs von den Lungen 6 (KL-6) in bronchoalveolar lavage (BAL) fluid of patients with IPF and idiopathic NSIP (i-NSIP) with fibrotic pattern. Thirty patients with IPF (68.73 ± 8.63 years), 30 with i-NSIP (68.33 ± 7.45 years), and healthy controls were included in the study. Calgranulin B and KL-6 both proved to be significantly higher in BAL of IPF and i-NSIP patients than in healthy controls (p < 0.05). Calgranulin B showed several significant correlations with functional parameters (oxygen demand at rest, 6-min walking test (6MWT), and PFTs); KL-6 was correlated with oxygen demand at rest and during 6MWT. Patients with higher concentrations of both biomarkers (> 75th percentile) had more advanced disease with lower values of FEV1%, FVC%, RV%, TLC%, DLCO% of predicted, distance walked in 6MWT, and BAL neutrophil percentage. Calgranulin B and KL-6 in BAL proved to be reliable biomarkers of IPF and i-NSIP and to have prognostic meaning, discriminating severe and advanced patients. The combination of the two biomarkers can facilitate the stratification of severity. [ABSTRACT FROM AUTHOR]

Abstract The sialic glycoprotein, MUC1 , is known to be involved in the pathogenesis of various types of cancers. KL-6 is one of the surface antigens of MUC1 and also a marker of interstitial pneumonitis. A fraction of patients with myeloma (3.9%) have elevated serum KL-6 levels without any evidence of interstitial pneumonitis and their myeloma cells have high MUC1 expression. We established a myeloma cell line designated EMM1 from a patient with multiple myeloma accompanied with elevated serum KL-6. EMM1 cells expressed high levels of MUC1 compared with other myeloma cell lines. Knockdown of MUC1 in EMM1 cells induced cell cycle arrest during S phase and apoptosis, suggesting that the MUC1 expression is involved in accelerated growth of EMM1 cells. RNA-seq analysis suggests that MUC1 expression activates k -ras and TNFα-induced NFκB pathways in EMM1 cells. We injected EMM1 cells subcutaneously into Rag2−/−Jak3−/− Balb/c mice to establish a mouse xenograft model. These mice had aggressive tumor growth that was accompanied by high serum KL-6 levels. In addition, MUC1 knockdown in EMM1 cells led to inhibited tumor growth. These findings demonstrate that MUC1 serves as a potential target for developing drugs for treatment of patients with KL-6+ myeloma, and EMM1 cells and EMM1-engrafted mice are useful tools for the development of such novel agents. Highlights • EMM cell line was established from a patient with serum KL-6 elevation. • EMM1 is the first myeloma cell line that expresses high levels of MUC1. • Knockdown of MUC1 induces S phase cell cycle arrest and apoptosis in EMM1 cells. • Xenograft mice with EMM1 cells reproduce the MM patient with serum KL-6 elevation. • Knockdown of MUC1 inhibits EMM1 tumor growth in a mouse xenograft model. [ABSTRACT FROM AUTHOR]

KL-6 is known as a useful serum biomarker of the disease activity in interstitial pneumonias. We investigated its usefulness as a biomarker for subtyping intraductal papillary mucinous neoplasms (IPMNs) of the pancreas. IPMNs are generally divided into 4 subtypes, namely pancreatobiliary (PB), intestinal (INT), gastric (GS), and oncocytic (ONC). Aside from the KL-6 antibody, the MUC1, MUC2, MUC5AC, MUC6, and MIB-1 antibodies were also examined. Eighteen IPMN cases were examined, including 12 cases of intraductal papillary mucinous carcinomas (IPMCs) simultaneously associated with dysplasia (IPMDs) and hyperplasia (IPMHs) and 6 IPMD cases with IPMH. KL-6 antibody was positive in the 8 IPMC cases, corresponding to a MUC2-negative PB subtype, but negative in 4 IPMC cases, corresponding to the INT subtype, which is positive for MUC2. IPMD of moderate-to-severe degree positively stained for the KL-6 antibody in the IPMC cases of the PB subtype but not in those of the INT subtype. The IPMH cases were mostly negative for KL-6, similar to the mild IPMD cases. In the 6 cases of mild IPMD and/or IPMH, KL-6 and MUC2 expressions were mostly negative. In conclusion, the KL-6 antibody is immunohistochemically a good biomarker of the PB subtype of IPMC, but not the INT subtype. Identifying IPMN subtypes based on KL-6 stainability would be useful. Clinicopathological studies with more IPMC cases might be needed for further progress in this field of study. [ABSTRACT FROM AUTHOR]

We present 3 cases of rapidly progressive interstitial pneumonia (RPIP) associated with clinically amyopathic dermatomyositis (C-ADM) that were treated with two courses of direct hemoperfusion with polymyxin B-immobilized fiber column (PMX-DHP). Despite initial treatment with high-dose corticosteroids, pulsed cyclophosphamide, and cyclosporine, the lung disease and hypoxemia deteriorated in all the patients. After PMX-DHP treatment, the PaO2/FiO2 ratio and serum LDH and KL-6 were improved, the abnormal shadows in chest high-resolution computed tomography (HRCT) scans gradually decreased, and, finally, all patients survived. These findings indicate that PMX-DHP treatment could be effective in the management of RPIP in patients with C-ADM in combination with conventional therapy. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study is to determine whether serum KL-6 and surfactant protein D (SP-D) levels predict the prognosis of patients with interstitial pneumonia (IP) in cases of polymyositis (PM) and dermatomyositis (DM). Patients and methods: Fifty consecutive patients with PM ( n = 17) or DM ( n = 33) and active IP, 6 of whom died of respiratory failure, were enrolled in this study. Serum KL-6 and SP-D levels were measured every 2-4 weeks. Medical records were reviewed retrospectively. Univariate analyses and multivariate analyses with a logistic regression model were conducted. Results: Serum KL-6 and SP-D levels were elevated in patients with active IP. At the time of diagnosis of active IP, the serum KL-6 level was within the normal range in 28 % of patients and the SP-D level was within the normal range in 46 % of patients. Serum KL-6 level increased up to 3 months after starting treatment and then decreased gradually to baseline, whereas SP-D level peaked within the first 4 weeks after treatment and decreased rapidly to normal levels. Patients with poor prognosis showed increases in KL-6 and SP-D levels during the first 4 weeks after treatment, which was confirmed by uni- and multivariate analyses. Comparing the marker levels at 2-4 weeks after treatment with those at 0 weeks, an increase in the ratio over 1.70 for KL-6 and over 1.75 for SP-D, and an increase in KL-6 over 850 U/ml during the first 4 weeks after treatment, were poor prognostic factors. Conclusions: Increases in serum KL-6 and SP-D levels during the first 4 weeks after starting therapy, but not their levels at any one time point, predict poor prognosis in patients with PM/DM. When marked increases of KL-6 and SP-D levels during the first 4 weeks are found or are predicted by serial measurement of the markers, patients have risks of poor prognosis and additional therapy should be considered. [ABSTRACT FROM AUTHOR]

Background: Elevated levels of KL-6 are reported in the serum and/or bronchoalveolar lavage fluid (BALF) of patients with interstitial lung disease (ILD) and are useful to estimate the severity and prognosis of the disease. However, whether the anti-KL-6 antibody could attenuate pulmonary fibrosis remains unclear. Objectives: This study aims to investigate the therapeutic effects and mechanisms of anti-KL-6 antibody on bleomycin-induced pulmonary fibrosis. Methods: A mouse model of pulmonary fibrosis was established by intratracheal injection of bleomycin (5 mg/kg). Mouse received anti-KL-6 antibody (20 ug/day, once a day) from day 7 to 21 after bleomycin injection. The effects of anti-KL-6 antibody were evaluated by pathological examination, measuring hydroxyproline measurements in lung tissues, leukocyte counts in BALF and the expression of collagen type I and type III using qRT-PCR. The expression of profibrotic cytokine (transforming growth factor-β1, TGR-β1), antifibrotic cytokine (hepatocyte growth factor, HGF), and KL-6 in lung tissues were analyzed by ELISA. The apoptosis of epithelial cell was examined by TUNEL staining. Results: Anti-KL-6 antibody significantly reduced the number of alveolar inflammatory leukocytes (total and differential counts) in BALF of mice with bleomycin-induced pulmonary fibrosis as well as the content of hydroxyproline in the lung tissues. Treatment with anti-KL-6 antibody downregulated the expression of collagen type I, TGF-β1 and KL-6, upregulated the expression of HGF and inhibited the apoptosis of epithelial cells. Conclusions: These findings indicated the anti-KL-6 antibody may potentially be developed as a useful inhibitor of pulmonary fibrosis. [ABSTRACT FROM AUTHOR]

Objective: The associations between elevated levels of serum Krebs von den Lungen-6 (KL-6) and treatment of rheumatoid arthritis (RA) with tumor necrosis factor (TNF) inhibitors were investigated in five Japanese clinical trials. Methods: Percentages and incidence rates were calculated for elevated serum KL-6 levels. Adverse events associated with elevated levels of serum KL-6 were investigated. Results: In RISING, a clinical trial for infliximab, 15.6 % of the enrolled patients met criterion B (KL-6 ≥500 U/ml and >1.5-fold increase over the baseline value) by week 54. In HIKARI, 7.8 % of the certolizumab pegol (CZP) group and 0 % of the placebo group met criterion B during the double-blind (DB) period ( p = 0.003). In J-RAPID, 8.4 % of the methotrexate (MTX) + CZP and 3.9 % of the MTX + placebo groups met criterion B during the DB period. In GO-MONO, 1.8 % of the golimumab (GLM) and 1.3 % of the placebo groups met criterion B during the DB period. In GO-FORTH, 7.1 % of the MTX + GLM and 0 % of the MTX + placebo groups met criteron B during the DB period ( p = 0.017). No adverse events accompanied the elevation of serum KL-6 levels in 95.7 % of these patients. Conclusion: Serum KL-6 levels may increase during anti-TNF therapy without significant clinical events. In these patients, continuing treatment with TNF inhibitors under careful observation is a reasonable option. [ABSTRACT FROM AUTHOR]

Background: Napsin A, an aspartic protease, is mainly expressed in alveolar type-II cells and renal proximal tubules and is a putative immunohistochemical marker for pulmonary adenocarcinomas. This study sought to determine whether napsin A could be measured in the serum to evaluate its relationship to idiopathic pulmonary fibrosis (IPF) and determine whether renal dysfunction might affect serum napsin A levels. Methods: Serum levels of napsin A were measured in 20 patients with IPF, 34 patients with lung primary adenocarcinoma, 12 patients with kidney diseases, and 20 healthy volunteers. Surfactant protein (SP)-A, SP-D, and Krebs von den Lungen-6 (KL-6) levels in serum and pulmonary function tests were also evaluated in IPF patients. Results: Circulating levels of napsin A were increased in patients with IPF, as compared with healthy controls, and they correlated with the severity of disease. Moreover, the serum napsin A levels were not elevated in patients with pulmonary adenocarcinoma or renal dysfunction. The distinguishing point between IPF and the controls was that the area under the receiver operating characteristic curve (ROC) of napsin A was larger than that of KL-6, SP-A, or SP-D. Conclusion: These findings suggest that serum napsin A may be a candidate biomarker for IPF. [ABSTRACT FROM AUTHOR]

Background: Bronchiolitis obliterans syndrome (BOS) is a life-threatening complication after lung transplantation that is characterized by progressive fibrosis in the small airways. However, little is known about sensitive markers for detecting BOS. Our study compared the clinical utility of serum KL-6 level, a marker for pulmonary fibrosis, with that of neutrophilia in bronchoalveolar lavage fluid (BALF) for detecting BOS. Methods: Levels of serum KL-6 were evaluated in 152 samples from 53 lung transplant recipients (BOS, 15; non-BOS, 38) and in 27 samples from age- and sex-matched healthy individuals. Pulmonary function tests, arterial blood gas analysis, and BALF cell differentials were simultaneously evaluated. Results: Serum KL-6 levels were significantly increased in the BOS group compared with the non-BOS group and the healthy individuals (p < 0.0001). Receiver operating characteristic curve analysis for detecting BOS showed the largest area under the curve for KL-6 compared with lactate dehydrogenase, C-reactive protein, or neutrophils percentage in BALF. Serum KL-6 correlated with the decline in forced expiratory volume in 1 second (FEV1) from post-lung transplant baseline (r = 0.43; p = 0.0001). Conclusions: Serum KL-6 levels are increased and correlate with the decline from baseline in FEV1 in lung transplant recipients. The diagnostic accuracy of serum KL-6 level is better than that of BALF neutrophilia for detecting BOS. [ABSTRACT FROM AUTHOR]

Background: A high incidence of interstitial lung disease (ILD) has been reported in patients with advanced non-small cell lung cancer (NSCLC) treated with epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs), particularly in Japanese populations. A previous report from our laboratory demonstrated that KL-6 was a useful serum biomarker to assess the severity of drug-induced pneumonitis. Based on these observations, this study was conducted to evaluate the risk factors of EGFR-TKIs induced ILD and the usefulness of monitoring serum KL-6 levels in patients who developed EGFR-TKIs induced ILD in a large multi-institutional setting.Methods: We retrospectively reviewed clinical records and radiographies of 341 patients with advanced NSCLCs who were treated with EGFR-TKIs, and analyzed risk factors for the development of EGFR-TKIs induced ILD. Changes of circulating levels of KL-6 were also evaluated in the patients who developed EGFR-TKIs induced ILD.Results: Among the 341 patients included in this study, 20 (5.9%) developed EGFR-TKIs induced ILD, and 9 (2.6%) died from ILD. Univariate analyses revealed that only preexisting pulmonary fibrosis was a significant risk factor for the development of EGFR-TKIs induced ILD (p = 0.003). Absolute levels of circulating KL-6 at neither baseline nor the onset of ILD could discriminate between life-threatening and non-life threatening EGFR-TKIs induced ILDs. However, we found that the ratios of serum KL-6 levels just after the onset of EGFR-TKIs induced ILD to those at baseline could quite precisely distinguish survivors from non-survivors (p = 0.006) as well as acute interstitial pneumonia (AIP) pattern from non-AIP pattern (p = 0.005).Conclusions: The results of this study strongly support the potential of KL-6 as a diagnostic biomarker for life-threatening EGFR-TKIs induced ILD. Monitoring of KL-6 is also useful to evaluate the progression and severity of EGFR-TKIs induced ILD. [ABSTRACT FROM AUTHOR]

Summary: Backgrounds: Fibrotic nonspecific interstitial pneumonia (f-NSIP) has been recognized as a distinct disease entity. KL-6 has been reported to be a useful serum marker in interstitial lung diseases. However, few previous reports evaluated the value of serum KL-6 exclusively in f-NSIP, as distinct from other subtypes of idiopathic interstitial pneumonia, therefore the associations of serum KL-6 with clinical and radiologic findings in this population remain unclear. Methods: Serum KL-6 levels were measured in twenty-six consecutive patients with f-NSIP diagnosed by surgical lung biopsy. Pulmonary function testing, bronchoalveolar lavage, subjective measurement of dyspnea using baseline dyspnea index (BDI), and HRCT were performed in parallel. Two radiologists conducted independent visual examinations of the pattern and extent of abnormalities on HRCT. Results: Serum KL-6 levels were elevated above the cut-off level in all patients. In univariate analysis serum KL-6 levels showed negative correlations with BDI (rho=−0.52; p <0.01). Serum KL-6 had positive correlations with the extent of several patterns of opacities (rho=0.56–0.62; p <0.01). Among them, only the extent of traction bronchiectasis in HRCT showed significant association with serum KL-6 in multivariate analysis (β-coefficient=0.043; p <0.01). Conclusions: Serum levels of KL-6 were elevated in f-NSIP, and were correlated with the extent of fibrotic abnormalities on HRCT, suggesting a value of serum KL-6 as a marker for fibrosis in f-NSIP. [Copyright &y& Elsevier]

Interstitial pneumonia with autoimmune features (IPAF) belongs to a group of diseases called interstitial lung diseases (ILDs), which are disorders of a varied prognosis and course. Finding sufficiently specific and sensitive biomarkers would enable the progression to be predicted, the natural history to be monitored and patients to be stratified according to their treatment. To assess the significance of pulmonary fibrosis biomarkers studied thus far, we searched the PubMed, Medline and Cochrane Library databases for papers published between January 2015 and June 2021. We focused on circulating biomarkers. A primary review of the databases identified 38 articles of potential interest. Overall, seven articles fulfilled the inclusion criteria. This review aims to assess the diagnostic and prognostic value of molecules such as KL-6, SP-A, SP-D, circulating fibrocytes, CCL2, CXCL13, CXCL9, CXCL10 and CXCL11. All of these biomarkers have previously been studied in idiopathic pulmonary fibrosis (IPF) and connective tissue disease-associated interstitial lung disease (CTD-ILD). IPAF is a disorder of a heterogeneous nature. It explains the lack of coherent observations in terms of correlations with functional parameters. There is still no meta-analysis of pulmonary fibrosis biomarkers in IPAF. This is mainly due to the heterogeneity of the methodology and groups analysed in the research. More research in this area is needed. [ABSTRACT FROM AUTHOR]

The immunohistochemical distribution of SP-D was compared with that of SP-A and KL-6 using a monoclonal antibody in lung tissues of 15 cases of collagen vascular disease-associated interstitial pneumonia (CVD-IP), 4 cases of hypersensitivity pneumonitis (CHP), and 6 cases of other diseases to determine their differences in distribution. In this study, the main targets were alveolar epithelial cells, especially those in the regenerating stage, as well as lymph vessels and stroma. The cytoplasm of type II alveolar epithelial cells and Clara cells was positive for SP-D, with sharp margins; interestingly, however, during the process of regeneration large positive cells were intermingled with relatively small negative cells, even in the same row of cells. In sharp contrast, staining for SP-A and KL-6 was positive in the cytoplasm of all the regenerating alveolar epithelial cells, as well as Clara cells. Staining for KL-6 was usually positive in the surface of air spaces in linear fashion. Staining for SP-A was also positive in elastic fibers in vascular walls. In areas of destruction of pulmonary structures, loose stroma and the endothelial cells of lymph vessels as well as their contents were distinctly positive for SP-A and/or KL-6 but not SP-D. Judging from these results in pulmonary tissues of CVD-IP and HP, SP-D might be a marker for maturity of regenerating epithelial cells. Both SP-A and KL-6 were detected in intimate relationship to the stage of regeneration of alveolar epithelial cells and were expressed before SP-D. In addition, the lymph vessels play a very important role in transfer of KL-6 into the bloodstream. [ABSTRACT FROM AUTHOR]

The article focuses on a study by the authors that measured the level of thymus and activation-regulated chemokine (TARC)/CCL17, eotaxin/CCL11, and surfactant protein-D (SP-D) in serum of patients with acute parenchymal lung diseases including interstitial pneumonia (AIP), pneumonia-associated acute lung injury (ALI) and acute eosinophilic pneumonia (AEP). The study concludes that measurement of KL-6 and circulating TARC/CCL17 helps in distinguishing AEP from other causes of ALI.

Objectives. KL-6 is a specific marker in patients with interstitial lung diseases (ILDs); however, the relationship between elevated levels of KL-6 and subsequent mortality is not well defined. To determine if elevated serum levels of KL-6 are associated with increased mortality, and to identify the most suitable cut-off level of KL-6 by which to distinguish between good prognosis and poor prognosis, we evaluated the prognostic significance of serum KL-6 levels in patients with stable-state ILDs. Methods. Two hundred and nineteen patients diagnosed with ILDs (152 with idiopathic interstitial pneumonia and 67 with collagen disease-associated pulmonary fibrosis) at Tsukuba University Hospital from April 1999 to October 2005 were entered in this study. Serum KL-6 levels in patients with ILDs were measured with a commercially available enzyme immunoassay kit, and these patients were then followed up. Results. During the follow-up period, 58 of the 219 patients died of respiratory failure. Patients who died during this period had higher levels of KL-6 than did those who did not ( P = 0.0004). The receiver operating characteristic curve analysis showed 1000 U mL−1 as the most suitable cut-off level by which to distinguish between the two groups of patients. The 95% specificity serum KL-6 level with poor outcome was 2750 U mL−1. In univariate and multivariate analysis, elevated serum KL-6 (>1000 U mL−1) in the stable state indicated poor prognosis ( P = 0.0005, log-rank test; P = 0.0001, Cox proportional hazard model). Conclusions. Elevated KL-6 level may provide simple, yet valuable information by which to identify patients with ILDs who are at increased risk for subsequent mortality. [ABSTRACT FROM AUTHOR]

The article presents information on the findings of a study focusing on identifying and quantifying nerve growth factor (NGF) in serum and peripheral blood lymphocyte culture from pigeon fanciers. NGF has been described in asthma and idiopathic pulmonary fibrosis as it contributes to neurogenic inflammation. The association of NGF with the immune response to inhaled avian antigens were also studied. The concentrations of NGF in serum and in lung lavage fluid reflected disease severity.

The balance between CD4 + T helper (Th1) lymphocytes producing interferon-γ or Interleukin-4 (Th2) in the lungs may vary among diseases and during the progression of interstitial pneumonia (IP). Both idiopathic pulmonary fibrosis (IPF) and collagen vascular diseases (CVD) are associated with IP, but the clinical course and the response to treatment are different. Since Th1 or Th2 modulating drugs have been proven to alter the lymphocyte balance in vitro, it is important to elucidate the Th1/Th2 profile in patients with active IP. Bronchoalveolar lavage (BAL) was performed in patients who had IPF ( n = 12) or CVD ( n = 12) with IP, as well as in patients who had bronchoectasis and bronchopneumonia ( n = 12). The CVD patients had rheumatoid arthritis ( n = 6), Sjogren's syndrome ( n = 2), dermatomyositis ( n = 1), progressive systemic sclerosis ( n = 2), and CREST syndrome ( n = 1) as the underlying diseases. IP activity was evaluated by measuring serum KL-6, which is a clinically useful indicator for IP. The Th1/ Th2 balance and the CD4 + /CD8 + ratio were determined for lymphocytes obtained from BAL by flow cytometric analysis. In IPF patients, the CD4 + /CD8 + ratio was lower than in CVD patients. IPF patients showed Th2 dominance and CVD patients showed Th1 dominance when IP was active as evaluated by the serum KL-6 level. These data indicated that the Th1/Th2 balance of CD4 + T cells in the BAL differs between active IPF and CVD, even though KL-6 is elevated in both diseases. Therefore, the Th1/Th2 profile should be investigated to determine the use of Th1/Th2 modulator therapy for active IP with elevation of KL-6. [ABSTRACT FROM AUTHOR]

Objective: Idiopathic pulmonary fibrosis poses a significant therapeutic challenge because of its progressive course. Since oxidative stress plays an important role in the pathogenesis of idiopathic pulmonary fibrosis, an open, randomized trial of long-term inhalation therapy with the antioxidant, N-acetylcysteine was conducted. Methodology: A total of 30 patients with idiopathic pulmonary fibrosis were randomly assigned to one of the following inhalation therapies: N-acetylcysteine (352 mg per day) or bromhexine hydrochloride (4 mg per day) as the control. Efficacy was assessed by analysing changes occurring from baseline to 12 months in pulmonary function, the 6-min walking test, high-resolution CT, healthrelated quality of life, and serum KL-6-values. Results: Four patients ( n = 2 in each group) died within 12 months due to progression of idiopathic pulmonary fibrosis. A total of 22 patients (control, n = 12; N-acetylcysteine, n = 10) completed the study. At 12 months there were significant differences between the N-acetylcysteine and control groups in terms of mean changes in lowest SaO2 during the 6-min walking test ( -0.3 ±2.1% vs -6.8 ± 1.8%, P < 0.05), serum KL-6 ( -482 ± 220 U/mL vs 176 ± 204 U/mL, P < 0.05), and the groundglass score on high-resolution CT ( -1.3 ± 1.6 vs 6.7 ± 1.5, P < 0.01). No significant differences were observed in pulmonary function, 6-min walking distance or quality of life. Conclusions: These data suggest that although long-term aerosolized N-acetylcysteine administration did not influence pulmonary function or quality of life, it may delay disease progression as evidenced by exercise desaturation, high-resolution CT, and serum KL-6. [ABSTRACT FROM AUTHOR]

A 56-year-old woman was admitted for interstitial pneumonia, and subsequently diagnosed with idiopathic non-specific interstitial pneumonia with a bronchiolitis obliterans organizing pneumonia pattern, on the basis of clinical and surgical lung biopsy findings. Histological findings revealed diffuse thickness of alveolar walls accompanied by lymphocyte infiltration and fibrosis in the lobules. In addition to those findings, granulation tissue was extensive. Although initial symptom and CT improvement occurred following high-dose prednisolone therapy, the CT did not show further improvement and her serum KL-6 level began increasing again as prednisolone was reduced. With the addition of colchicine therapy, clinical and CT findings improved remarkably and a further reduction of the prednisolone dose was achieved. This case suggests that the combination of colchicine and corticosteroids may be an effective therapy for non-specific interstitial pneumonia. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate when the serum level of KL-6, a sensitive marker for idiopathic pulmonary fibrosis (IPF), rise prior to clinical onset of IPF. Eight hepatitis C virus (HCV)-positive patients with IPF were enrolled in this trial. The serum samples of these eight patients were stored −80 °C every 1–3 month during a follow-up period and enzyme-linked immunosorbent assay (ELISA) for KL-6 was done at the same time. Diagnosis of IPF was based on computed tomography and/or histology. Diagnosis of clinical onset of IPF was based on presence of dyspnea, dry cough, and audible fine crackles. At 1 year before clinical onset of IPF, the sensitivities of serum marker for IPF were 75% (6/8) for KL-6, 25% (2/8) for each of lactic acid dehydrogenase (LDH) and C-reactive protein (CRP). At 2 years before clinical onset of IPF, the sensitivities of the same serum markers were 62.5% (5/8), 12.5% (1/8) and 0% (0/8), respectively. The sensitivity of KL-6 at 1 and 2 year before clinical onset of IPF was significantly higher compared with LDH and CRP. Our results indicate that many future patients with IPF may have high levels of serum KL-6 at 1 or 2 years before clinical onset of IPF, suggesting that changes in serum KL-6 level can provide useful information for the early diagnosis of IPF in patients with HCV. [Copyright &y& Elsevier]

Interstitial pneumonia (IP) is a serious adverse event of interferon alpha (IFNα) treatment for chronic hepatitis C (CH-C). Among 558 CH-C patients who received IFNα treatment with or without ribavirin between January 1992 and June 2002, six patients (1.1%) developed IP, including one patient who developed IP in 1993 and again in 2002. Among the seven cases who contracted IP, at the onset of IP, seven (100%), five (71%), and two cases (29%) had elevated serum levels of KL-6, surfactant protein A (SP-A), and surfactant protein D (SP-D), respectively. Prior to starting IFN treatment (baseline), the serum SP-A and SP-D levels were within the normal range in all seven cases, but the serum KL-6 level was elevated in five of the seven cases, contrasting with that in three of 48 age-adjusted CH-C patients who did not develop IP during IFN treatment (71 vs. 6%; P=0.0003). Furthermore, the circulating KL-6 level at baseline was significantly higher among the seven cases than among the controls (543±105 vs. 304±98 U/ml, P=0.0001). These results indicate that measurement of the circulating KL-6 level in CH-C patients before IFN treatment may be useful for predicting the occurrence of IP during IFN treatment. [Copyright &y& Elsevier]

A 73-year-old woman with idiopathic pulmonary fibrosis (IPF) had an elevated serum CA19-9 level, but not KL-6. Her condition worsened and she subsequently died and this was associated with a rise in the serum KL-6 level. At autopsy, the lung showed a honeycomb appearance macroscopically and, microscopically, hyaline membrane formation was seen. Immunohistochemical staining revealed partial colocalization of KL-6 and CA19-9 to dilated bronchiolar cells. These features suggest that the mechanisms that cause the synthesis and release of CA19-9 and KL-6 from damaged lung tissue in IPF are likely to differ from those in diffuse alveolar damage. In addition, serum KL-6 levels may reflect the severity of disease more sensitively than CA19-9 levels. [ABSTRACT FROM AUTHOR]