Clinical use of biomarkers of survival in pulmonary fibrosis

Serum lactate dehydrogenase and its isoenzymes as predictors of clinical outcomes in acute exacerbation of chronic obstructive pulmonary disease: a retrospective analysis of a hospitalized cohort

We aimed to test the relationship between serum lactate dehydrogenase (LDH) and its isoenzymes and treatment outcomes during hospitalization for acute exacerbations of chronic obstructive pulmonary disease (AECOPD). Thirty-eight AECOPD patients were recruited from a tertiary hospital from December 2017 to June 2018. Serum LDH and LDH isoenzymes were measured on venous blood collected at admission. Treatment outcomes included duration of hospital stay, initiation of mechanical or non-invasive ventilation (NIV), initiation of antipseudomonal antibiotics, change in empirical antibiotic treatment, need for intravenous corticosteroids or methylxanthines, and percentage of change in C-reactive protein from admission to the third day. Multivariate linear and binary logistic regression analyses were used to test the study's objectives. We found that, after adjusting for age, gender, comorbidities, COPD severity, level of hypoxemia, and inflammation markers, each 10 U/L increase in serum LDH was associated with prolongation of the hospital stay by 0.25 (0.03, 0.46) days, 42% higher odds [odds ratio (OR) 1.42 (1.00, 2.03)] for need of NIV, and 25% higher odds [OR 1.25 (1.04, 1.49)] for initiation of antipseudomonal treatment. LDH1 and LDH2 were the LDH isoenzymes that mainly drove these relationships. LDH release in the context of an AECOPD could originate from lung, muscle, or heart tissue damage due to airway inflammation, respiratory muscle recruitment, and myocardial stress. Myocardial injury and aerobic adaptation in respiratory muscles may explain the predominance of LDH1 and LDH2 isoenzymes in these associations.

The Challenging Diagnosis of Interstitial Lung Disease in Children-One Case Report and Literature Review

Childhood interstitial lung disease (chILD) includes a heterogeneous spectrum of rare respiratory disorders in children associated with substantial morbi-mortality. Interstitial tissue, and other pulmonary structures, epithelium, blood vessels, or pleura are involved, resulting in a restrictive lung disfunction. Respiratory symptoms set in progressively and are often subtle, making thorough clinical history and physical examination fundamental. The etiology often is obscure. The clinical presentation mimics pneumonia or asthma, leading to a diagnostic delay. Challenging diagnosis may require genetic tests, bronchoalveolar lavage, or lung biopsy. Alongside general supportive therapeutic measures, anti-inflammatory, immunosuppressive or antifibrotic agents may be used, based on data derived from adult studies. However, if accurate diagnosis and treatment are delayed, irreversible chronic respiratory failure may ensue, impacting prognosis. The most frequent chILD is hypersensitivity pneumonitis (HP), although it is rare in children. HP is associated with exposure to an environmental antigen, resulting in inflammation of the airways. Detailed antigen exposure history and identification of the inciting trigger are the cornerstones of diagnostic. This article provides the current state of chILD, revealing specific features of HP, based on a clinical case report of a patient admitted in our clinic, requiring extensive investigations for diagnosis, with a favorable long-term outcome.

Pulmonary long-term consequences of COVID-19 infections after hospital discharge

OBJECTIVES

Coronavirus disease 2019 (COVID-19) survivors are reporting residual abnormalities after discharge from hospital. Limited information is available about this stage of recovery or the lingering effects of the virus on pulmonary function and inflammation. This study aimed to describe lung function in patients recovering from COVID-19 hospitalization and to identify biomarkers in serum and induced sputum samples from these patients.

METHODS

Patients admitted to Spanish hospitals with laboratory-confirmed COVID-19 infection by a real-time PCR (RT-PCR) assay for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were recruited for this study. Each hospital screened their lists of discharged patients at least 45 days after symptom onset. SARS-CoV-2-infected patients were divided into mild/moderate and severe disease groups according to the severity of their symptoms during hospitalization. Patients' epidemiological and medical histories, comorbidities, chronic treatments, and laboratory parameters were evaluated. Pulmonary function tests, the standardized 6-minute walk test (6MWT) and chest computed tomography (CT) were also performed. The levels of proteases, their inhibitors, and shed receptors were measured in serum and induced sputum samples.

RESULTS

A total of 100 patients with respiratory function tests were included in this study. The median number of days after the onset of symptoms was 104 (IQR 89.25, 126.75). COVID-19 was severe in 47% of patients (47/100). CT was normal in 48% of patients (48/100). Lung function was normal forced expiratory volume in one second (FEV1) ≥80%, forced vital capacity (FVC) ≥80%, FEV1/FVC ≥0.7, and diffusing capacity for carbon monoxide (DLCO) ≥80% in 92% (92/100), 94% (94/100), 100% (100/100) and 48% (48/100) of patients, respectively. Multivariate analysis showed that a DLCO <80% (OR 5.92; 95%CI 2.28-15.37; p < 0.0001) and a lower serum lactate dehydrogenase level (OR 0.98; 95%CI 0.97-0.99) were associated with the severe disease group of SARS-CoV-2 cases during hospital stay.

CONCLUSIONS

A diffusion deficit (DLCO <80%) was still present after hospital discharge and was associated with the most severe SARS-CoV-2 cases.

Serum Krebs von den Lungen (KL-6) level as a marker of exacerbation of interstitial lung diseases

Background

Krebs von den Lungen (KL-6) is elevated in serum of interstitial lung disease (ILD) patients based on its leakage from the alveolar space into the blood; KL-6 is significantly higher in patients with acute exacerbation of ILDs (AE-ILD) compared with stable patients. This study aimed to determine the sensitivity and specificity of KL6 to detect AE-ILD.

Results

This is a prospective cross sectional observational study was carried out on 88 subjects at the Chest Department, Minia Cardiothoracic University Hospital, during the period from August 2018 to August 2019. This study was approved by the hospital research ethics board of Minia University and informed consent was obtained. History, examination, spirometry, ABGs, X-ray, HRCT, CBC, ESR, CRP, and KL6 levels were done to both stable and exacerbation groups of ILDs. The level of biomarkers is compared between both groups and control.

Statistical analysis done by using IBM SPSS statistical package version 20 (χ2 test and independent sample t test, ANOVA test, bivariate Pearson correlation analysis, and ROC curve analysis).

The study showed that there is a significant difference between stable and exacerbating groups regarding fever, signs of RHF, dyspnea scale, FVC, and PaO2.

Conclusion

KL-6 cutoff ≥ 187.5 U/ml could exhibit AE-ILDs with a sensitivity of 98% and a specificity of 97%. KL-6 is a more sensitive and specific marker to detect AE-ILD.

C-proSP-B: A Possible Biomarker for Pulmonary Diseases?

BACKGROUND

Detection of surfactant proteins A and D (SP-A and SP-D) in the serum of patients with pulmonary diseases is thought to reflect an injury of the alveolar epithelial barrier and as such serve as a biomarker for these diseases. However, the data for SP-B are limited.

OBJECTIVES

The aim of this feasibility study was to assess whether immature SP-B pre-proteins might have value as a possible biomarker for pulmonary diseases.

METHODS

In serum samples from patients with different chronic lung diseases (interstitial lung diseases [ILDs], chronic obstructive pulmonary disease, asthma, lung cancer, pulmonary hypertension, inflammation, patients on ventilator support; total n = 283), C-proSP-B was measured using an electrochemiluminescence immunoassay based on mouse monoclonal anti-C-proSP-B antibodies. Levels were correlated to lung functional and clinical parameters.

RESULTS

The highest C-proSP-B levels were detected in the serum of idiopathic pulmonary fibrosis (IPF) patients. In a multivariate analysis, C-proSP-B levels were able to discriminate IPF patients from patients with all other pulmonary diseases (p < 0.0001). No significant correlations were found between C-proSP-B levels and lung function, smoking history, or disease extent.

CONCLUSIONS

SP-B pre-proteins might serve as a biomarker in pulmonary diseases with alveolar or interstitial damage such as ILDs, especially in IPF. Their role in the long-term monitoring of such diseases has to be clarified further.

Predictors of short-term LAMA ineffectiveness in treatment naïve patients with moderate to severe COPD

BACKGROUND

No specific (only subgroup) recommendations for the use of long-acting muscarinic antagonists in chronic obstructive pulmonary disease (COPD) exist. The aim of this exploratory hypothesis generating study was to assess whether different phenotypic/endotypic characteristics could be determinants of the short-term ineffectiveness of the initial tiotropium bromide monotherapy in treatment naïve moderate to severe COPD patients.

METHODS

A total of 51 consecutively recruited COPD patients were followed for 3 months after the initial evaluation and prescribed initial treatment (tiotropium). Short-term treatment ineffectiveness was assessed as a composite measure comprising COPD exacerbations, need for additional treatment, and no improvement in functional parameters, e.g. 6‑min walking test (6MWT), body-mass index, airflow obstruction, dyspnea, and exercise (BODE) index and forced expiratory volume in 1 s (FEV₁), and as single components.

RESULTS

Treatment ineffectiveness was significantly associated with baseline hemoglobin level, COPD assessment test (CAT) score, modified Medical Research Council (mMRC) scale and BODE index (p = 0.002). Incident exacerbation during the follow-up was associated with baseline bronchoalveolar lavage fluid (BALF) alpha-amylase level and CAT score (p < 0.001), and change in treatment with leukocyte count, 6MWT desaturation and fatigue (p < 0.001). No improvement in 6MWT was associated with baseline CAT score, body mass index, mMRC, fatigue, 6MWT and BODE index (p = 0.002). No improvement in BODE index was associated with leukocyte count, serum interleukin 8 (IL-8) and BALF albumin levels (p < 0.001); and no improvement in FEV₁ with CAT score, baseline vital capacity and BALF tumor necrosis factor alpha (TNF-alpha) level (p < 0.001).

CONCLUSION

Our results suggest that there is a possibility to identify predictors of short-term tiotropium ineffectiveness in patients with moderate to severe COPD.

A functional genomic model for predicting prognosis in idiopathic pulmonary fibrosis

Background

The course of disease for patients with idiopathic pulmonary fibrosis (IPF) is highly heterogeneous. Prognostic models rely on demographic and clinical characteristics and are not reproducible. Integrating data from genomic analyses may identify novel prognostic models and provide mechanistic insights into IPF.

Methods

Total RNA of peripheral blood mononuclear cells was subjected to microarray profiling in a training (45 IPF individuals) and two independent validation cohorts (21 IPF/10 controls, and 75 IPF individuals, respectively). To identify a gene set predictive of IPF prognosis, we incorporated genomic, clinical, and outcome data from the training cohort. Predictor genes were selected if all the following criteria were met: 1) Present in a gene co-expression module from Weighted Gene Co-expression Network Analysis (WGCNA) that correlated with pulmonary function (p < 0.05); 2) Differentially expressed between observed “good” vs. “poor” prognosis with fold change (FC) >1.5 and false discovery rate (FDR) < 2 %; and 3) Predictive of mortality (p < 0.05) in univariate Cox regression analysis. “Survival risk group prediction” was adopted to construct a functional genomic model that used the IPF prognostic predictor gene set to derive a prognostic index (PI) for each patient into either high or low risk for survival outcomes. Prediction accuracy was assessed with a repeated 10-fold cross-validation algorithm and independently assessed in two validation cohorts through multivariate Cox regression survival analysis.

Results

A set of 118 IPF prognostic predictor genes was used to derive the functional genomic model and PI. In the training cohort, high-risk IPF patients predicted by PI had significantly shorter survival compared to those labeled as low-risk patients (log rank p < 0.001). The prediction accuracy was further validated in two independent cohorts (log rank p < 0.001 and 0.002). Functional pathway analysis revealed that the canonical pathways enriched with the IPF prognostic predictor gene set were involved in T-cell biology, including iCOS, T-cell receptor, and CD28 signaling.

Conclusions

Using supervised and unsupervised analyses, we identified a set of IPF prognostic predictor genes and derived a functional genomic model that predicted high and low-risk IPF patients with high accuracy. This genomic model may complement current prognostic tools to deliver more personalized care for IPF patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-015-0142-8) contains supplementary material, which is available to authorized users.

A novel genomic signature with translational significance for human idiopathic pulmonary fibrosis

The bleomycin-induced rodent lung fibrosis model is commonly used to study mechanisms of lung fibrosis and to test potential therapeutic interventions, despite the well recognized dissimilarities to human idiopathic pulmonary fibrosis (IPF). Therefore, in this study, we sought to identify genomic commonalities between the gene expression profiles from 100 IPF lungs and 108 control lungs that were obtained from the Lung Tissue Research Consortium, and rat lungs harvested at Days 3, 7, 14, 21, 28, 42, and 56 after bleomycin instillation. Surprisingly, the highest gene expression similarity between bleomycin-treated rat and IPF lungs was observed at Day 7. At this point of maximal rat-human commonality, we identified a novel set of 12 disease-relevant translational gene markers (C6, CTHRC1, CTSE, FHL2, GAL, GREM1, LCN2, MMP7, NELL1, PCSK1, PLA2G2A, and SLC2A5) that was able to separate almost all patients with IPF from control subjects in our cohort and in two additional IPF/control cohorts (GSE10667 and GSE24206). Furthermore, in combination with diffusing capacity of carbon monoxide measurements, four members of the translational gene marker set contributed to stratify patients with IPF according to disease severity. Significantly, pirfenidone attenuated the expression change of one (CTHRC1) translational gene marker in the bleomycin-induced lung fibrosis model, in transforming growth factor-β1-treated primary human lung fibroblasts and transforming growth factor-β1-treated human epithelial A549 cells. Our results suggest that a strategy focused on rodent model-human disease commonalities may identify genes that could be used to predict the pharmacological impact of therapeutic interventions, and thus facilitate the development of novel treatments for this devastating lung disease.

SUV as an adjunct in evaluating disease activity in idiopathic pulmonary fibrosis - a pilot study

OBJECTIVE

We hypothesize that the standardized uptake value (SUV) from PET/computed tomography (CT) can act as an adjunct to forced vital capacity (FVC) in evaluating disease status in idiopathic pulmonary fibrosis (IPF).

METHODS

Eight consecutive male patients diagnosed with IPF were prospectively recruited to undergo full pulmonary function tests, high-resolution computed tomography of the thorax and PET/CT. The corrected mean SUV (rSUVmean) and corrected maximum SUV (rSUVmax) against the mediastinal blood pool were correlated with clinical parameters. Examinations were repeated 6 months later in six patients (2/8 patients had died) and changes were evaluated. Correlation was assessed by Spearman's rank correlation, and statistical significance was considered when the P-value was less than 0.05.

RESULTS

The rSUVmean in IPF was negatively correlated with FVC (r=-0.6, P=0.024) and diffusing capacity for carbon monoxide (r=-0.7, P=0.010). The decline in FVC was associated with an increment in rSUVmax (r=-0.9, P=0.019), but no similar observation was made with total CT score (r=-0.1, P=0.787).

CONCLUSION

Pulmonary metabolism, rSUVmean, contributes to the functional status of IPF patients, and changes in rSUVmax may serve as an adjunct surrogate marker to FVC in evaluating the disease status in IPF patients.

Differences in serum SP-D levels between German and Japanese subjects are associated with SFTPD gene polymorphisms

BACKGROUND

Surfactant protein A (SP-A) and SP-D are clinically established in Japan as serum biomarkers for diagnosing interstitial lung diseases (ILDs). Serum SP-D levels are affected by genetic variants. We conducted the present study to examine whether serum SP-A and/or SP-D levels in healthy subjects (HS) and patients with ILDs differ between populations with different genetic backgrounds.

METHODS

German subjects (n = 303; 138 patients with idiopathic interstitial pneumonias [IIPs] and 165 HS) and Japanese subjects (n = 369; 94 patients with IIPs and 275 HS) were enrolled. Serum SP-A and SP-D levels were measured using an enzyme-linked immunosorbent assay, and four single-nucleotide polymorphisms (SNPs) in the SFTPD gene were genotyped using genomic DNA extracted from blood samples.

RESULTS

In both the German and Japanese cohorts, serum SP-A and SP-D levels were significantly higher in patients with IIPs than in HS. There were no significant differences in SP-A levels between the German and Japanese cohorts; however, we found that serum SP-D levels were significantly higher in the German cohort, both in patients with IIPs and in HS (p < 0.001 and p = 0.005, respectively). Furthermore, the genotype distributions of the four SNPs in the SFTPD gene (rs721917, rs1998374, rs2243639, and rs3088308) were significantly different between German and Japanese cohorts (p < 0.001, p < 0.001, p = 0.022, and p < 0.001, respectively), and univariate linear regression analyses revealed that the genotypes of rs721917, rs1998374, and rs2243639 significantly correlated with serum SP-D levels (p < 0.001, p < 0.001, and p = 0.011, respectively). Furthermore, multivariate analyses revealed that the genotypes of these three SNPs correlated independently with serum SP-D levels (p < 0.001, p = 0.001, and p = 0.038, respectively), whereas ethnicity did not significantly correlate with serum SP-D levels.

CONCLUSIONS

In patients with IIPs and HS, serum SP-D, but not SP-A, levels were significantly higher in the German than in the Japanese cohort, in part, because of the different frequencies of SFTPD gene polymorphisms.

Blood biomarkers MMP-7 and SP-A: predictors of outcome in idiopathic pulmonary fibrosis

BACKGROUND

Because of the variable course of idiopathic pulmonary fibrosis (IPF), it is important to generate an accurate prognosis at the time of diagnosis. The aim of this study was to investigate the prognostic value of blood biomarkers in IPF.

METHODS

The plasma level of the biomarkers, matrix metalloproteinase-7 (MMP-7), Krebs von den Lungen-6 antigen, and surfactant protein (SP)-A and SP-D were retrospectively compared with the clinical course of 118 patients with IPF, 68 of whom had biopsy-proven IPF.

RESULTS

The median follow-up period was 24 months. Multivariate Cox analysis showed MMP-7 (HR, 1.056; P = .0063) and SP-A (HR, 1.011; P = .0001) were significant predictors of survival along with age, FVC, and extent of honeycombing. The patients with high levels of both MMP-7 (≥ 12.1 ng/mL) and SP-A (≥ 80.3 ng/mL) had shorter survival (1-year survival rate: 59%) and higher frequency (42%) of lung function decline (&gt; 10% reduction in FVC in 6 months) compared with those with high levels of one biomarker (1-year survival rate: 81%; FVC decline: 27%) or low levels of both (1-year survival rate: 83.3%; FVC decline: 9%). Multivariate models demonstrated marginal improvement in the prediction of mortality (concordance index [C-index]: 0.731; P = .061) when MMP-7 and SP-A were included and compared with standard clinical predictors only (C-index: 0.686); however, it became significant with addition of MMP-7, SP-A, and Krebs von den Lungen-6 antigen (C-index: 0.730; P = .037).

CONCLUSIONS

Our retrospective study suggested that at least three biomarkers are necessary to improve predictability of mortality in IPF compared with clinical parameters. Further study in a greater number of patients is warranted.

Idiopathic pulmonary fibrosis: the need for early diagnosis

Idiopathic pulmonary fibrosis (IPF), a chronic fibrosing lung disease of a progressive nature and unknown etiology, has the largest epidemiological impact and the worst prognosis among the idiopathic interstitial pneumonias (IIP). Despite the progress in pathogenetic knowledge, many aspects are still dubious, in particular the biomolecular mechanisms activated in the early stages of the disease. Early diagnosis is desirable not only to better define aspects of the natural history of the disease, but also to customize treatment protocols. An early diagnosis of IPF should necessarily be based on the ability to highlight a number of features drawn not only from a careful composition of specific anamnestic data with clinical, functional and radiological parameters, but also from biological markers that, in a proper context, can provide guidance and confirm a clinical-anamnestic suspicion. The identification of specific biomarkers for IPF is a modern and attractive look for the potential clinical implications in terms of diagnosis, prediction of disease progression and prognosis. Biomolecular investigations on IPF were performed selectively on tissue samples, bronchoalveolar lavage (BAL), or blood: nowadays the “multi-omic” approach may allow studying individual constitutional profiles resorting to a series of biomolecular disciplines, the so-called “omics”, which focuses on responses of the entire genomic complex, in line with the current trend to quantitatively analyze the interactions of all components of a biological system. Such refined investigations are an essential base for research now, but they might become a routine in the near future, allowing a more precise classification of patients suffering from a disease of unclear taxonomy.

Noninvasive monitoring of pulmonary fibrosis by targeting matrix metalloproteinases (MMPs)

While idiopathic pulmonary fibrosis (PF) is a devastating lung disease, the management of PF including effective monitoring of disease progression remains a challenge. Herein, we introduce a novel, fast, and ultrasensitive metalloproteinase (MMP) activatable optical probe, named MMP-P12, to noninvasively monitor PF progression and response to PF treatment. A bleomycin (BLM)-induced mouse PF model was subjected noninvasively to optical imaging at various time points after BLM treatment. The mouse PF model developed fibrosis during 21 days of experimental period, and the progression of PF was well correlated with the stepwise increase of MMP-2 expression as examined by quantitative RT-PCR and Western blot analysis on the 7-, 14-, and 21-day post-BLM administration. On these days, MMP-activated fluorescence images were acquired in vivo and ex vivo. Signal quantification showed time-dependent lung-specific incremental increases in fluorescence signals. As a treatment for PF, secretoglobin 3A2 was daily administered intravenously for five days starting on day seven of BLM administration, which resulted in reduced MMP-2 activity and reduction of PF as previously demonstrated. Importantly, the fluorescence signal that reflected MMP activity also decreased in intensity. In conclusion, MMPs may play an important role in PF development and the MMP-P12 probe could be a promising tool for PF detection, even at an early stage of the disease as well as an indicator of therapy response.

Quantitative computerized two-point correlation analysis of lung CT scans correlates with pulmonary function in pulmonary sarcoidosis

BACKGROUND

Chest CT scans are commonly used to clinically assess disease severity in patients presenting with pulmonary sarcoidosis. Despite their ability to reliably detect subtle changes in lung disease, the utility of chest CT scans for guiding therapy is limited by the fact that image interpretation by radiologists is qualitative and highly variable. We sought to create a computerized CT image analysis tool that would provide quantitative and clinically relevant information.

METHODS

We established that a two-point correlation analysis approach reduced the background signal attendant to normal lung structures, such as blood vessels, airways, and lymphatics while highlighting diseased tissue. This approach was applied to multiple lung fields to generate an overall lung texture score (LTS) representing the quantity of diseased lung parenchyma. Using deidentified lung CT scan and pulmonary function test (PFT) data from The Ohio State University Medical Center's Information Warehouse, we analyzed 71 consecutive CT scans from patients with sarcoidosis for whom simultaneous matching PFTs were available to determine whether the LTS correlated with standard PFT results.

RESULTS

We found a high correlation between LTS and FVC, total lung capacity, and diffusing capacity of the lung for carbon monoxide (P &lt; .0001 for all comparisons). Moreover, LTS was equivalent to PFTs for the detection of active lung disease. The image analysis protocol was conducted quickly (&lt; 1 min per study) on a standard laptop computer connected to a publicly available National Institutes of Health ImageJ toolkit.

CONCLUSIONS

The two-point image analysis tool is highly practical and appears to reliably assess lung disease severity. We predict that this tool will be useful for clinical and research applications.

Serological investigation of the collagen degradation profile of patients with chronic obstructive pulmonary disease or idiopathic pulmonary fibrosis

In both chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), abnormally high collagen remodeling occurs within the lung tissue. Matrix metalloproteinase (MMP)-degraded type I, III, IV, V and VI collagen and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-degraded type III collagen were assessed in serum of patients diagnosed with mild COPD (n = 10) or IPF (n = 30), and healthy controls (n = 15). The collagen degradation markers C1M, C3M, C5M and C6M were significantly elevated in serum of both mild COPD and IPF patients, versus controls. C3A and C4M were only elevated in patients with mild COPD, compared with controls. The most reliable indicators of mild COPD versus controls were: C1M (area under the receiver-operating characteristics (AUROC = 0.94, P < 0.0001), C3M (AUROC = 0.95, P < 0.0001), and C5M (AUROC = 0.95, P < 0.0001). The most reliable markers for the diagnosis of IPF were achieved by C1M (AUROC = 0.90, P < 0.0001) and C3M (AUROC = 0.93, P < 0.0001). Collagen degradation was highly up-regulated in patients with IPF and mild COPD, indicating that degradation fragments of collagens are potential markers of pulmonary diseases. Interestingly, C4M and C3A were only elevated in patients with mild COPD, indicating that these markers could be used to distinguish between the two pathologies.

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.

Newer modes of treating interstitial lung disease

PURPOSE OF REVIEW

This review critically discusses recent advances in the treatment of idiopathic pulmonary fibrosis (IPF). Moreover, it also focuses on the practical approach of a patient diagnosed with IPF and uncovers challenges for the future.

RECENT FINDINGS

Treatment can be divided into three major parts. Firstly, many new agents have been tested, but only the combination of N-acetylcysteine with corticosteroids, azathioprine and pirfenidone was able to show some significant effects. In the mean time, many second-generation agents are under development. Lung transplantation has made some major progress by introducing an appropriate allocation system. Finally, as part of best supportive care, several studies show that pulmonary rehabilitation might induce some important effects on quality of life.

SUMMARY

So, it is clear that major progress has been made in the treatment of IPF, but we are convinced that an orchestrated effort will lead to a better understanding and treatment of this devastating condition.