Levels of YKL-40 in pleural effusions and blood from patients with pulmonary or pleural disease

Significance of chitinase-3-like protein 1 in the pathogenesis of inflammatory diseases and cancer

Chitinase-3-like protein 1 (CHI3L1) is a secreted glycoprotein that mediates inflammation, macrophage polarization, apoptosis, and carcinogenesis. The expression of CHI3L1 is strongly upregulated by various inflammatory and immunological diseases, including several cancers, Alzheimer's disease, and atherosclerosis. Several studies have shown that CHI3L1 can be considered as a marker of disease diagnosis, prognosis, disease activity, and severity. In addition, the proinflammatory action of CHI3L1 may be mediated via responses to various proinflammatory cytokines, including tumor necrosis factor-α, interleukin-1β, interleukin-6, and interferon-γ. Therefore, CHI3L1 may contribute to a vast array of inflammatory diseases. However, its pathophysiological and pharmacological roles in the development of inflammatory diseases remain unclear. In this article, we review recent findings regarding the roles of CHI3L1 in the development of inflammatory diseases and suggest therapeutic approaches that target CHI3L1.

Association between YKL-40 and asthma: a systematic meta-analysis

PURPOSE

Many studies have shown that chitinase-3-like protein 1 (CHI3L1), also known as YKL-40, is associated with asthma. The purpose of this meta-analysis was to evaluate the role of serum YKL-40 in the diagnosis and differential diagnosis of asthma, severity grading, and determination of disease state.

METHODS

The PubMed, Ovid, and Cochrane databases were searched. A total of 17 articles involving 5696 subjects were included in this meta-analysis.

RESULTS

The results showed that the level of YKL-40 was significantly higher in asthmatic patients than in the normal group regardless of age and residential location, and increased with severity and acute exacerbation (p < 0.05). YKL-40 levels were significantly different between chronic obstructive pulmonary disease (COPD) and asthma, and also between asthma-COPD overlap syndrome (ACO) and asthma (p < 0.05).

CONCLUSION

YKL-40 may act as a potential serological marker for the diagnosis of asthma, assessment of severity, indicator of the disease state, and differential diagnosis of COPD, ACO, and asthma.

The usefulness of biomarkers in diagnosis of asbestos-induced malignant pleural mesothelioma

INTRODUCTION

Malignant pleural mesothelioma (MPM) is a malignant tumor that is associated mostly with asbestos exposure. The present study was to evaluates the diagnostic value of neopterin, periostin, YKL-40, Tenascin-C (TNC), and Indolamine 2,3-dioxygenase (IDO) as noninvasive markers of malign pleural mesothelioma.

METHODS

Included in the study were 30 patients diagnosed with malign pleural mesothelioma, and 25 people as a control group. Biomarker levels were determined using an enzyme immunoassay . A Mann-Whitney U test and Spearman correlation methods were used for the statistical analysis.

RESULTS

All evaluated biomarkers were found to be significantly higher in the MPM group than in the control group (p < 0.05). There was no effect of such variables as gender, age or MPMsubtype on the parameters (p > 0.05) in the patient group. All biomarkers were positively correlated with each other (p < 0.001).

CONCLUSIONS

The current non-invasive biomarkers that can be used in the diagnosis of MPM yielded significant results and can make important contributions to the early diagnosis of MPM.

Pleural biomarkers in diagnostics of malignant pleural effusion: a narrative review

Although cytology and pleural biopsy of pleural effusion (PE) are the gold standards for diagnosing malignant pleural effusion (MPE), these tools’ diagnostic accuracy is plagued by some limitations such as low sensitivity, considerable inter-observer variation and invasiveness. The assessment of PE biomarkers may hence be seen as an objective and non-invasive diagnostic alternative in MPE diagnostics. In this review, we summarize the characteristics and diagnostic accuracy of available PE biomarkers, including carcinoembryonic antigen (CEA), neuron-specific enolase (NSE), carbohydrate antigens 125 (CA125), carbohydrate antigen 19-9 (CA19-9), carbohydrate antigen 15-3 (CA15-3), a fragment of cytokeratin 19 (CYFRA 21-1), chitinase-like proteins (CLPs), vascular endothelial growth factor (VEGF) and its soluble receptor, endostatin, calprotectin, cancer ratio, homocysteine, apolipoprotein E (Apo-E), B7 family members, matrix metalloproteinase (MMPs) and tissue-specific inhibitors of metalloproteinases (TIMPs), reactive oxygen species modulator 1 (Romo1), tumor-associated macrophages (TAMs) and monocytes, epigenetic markers (e.g., cell-free microRNA and mRNA). We summarized the evidence from systematic review and meta-analysis for traditional tumor markers’ diagnostic accuracy. According to the currently available evidence, we conclude that the traditional tumor markers have high specificity (around 0.90) but low sensitivity (around 0.50). The diagnostic accuracy of novel tumor markers needs to be validated by further studies. None of these tumor biomarkers would have sufficient diagnostic accuracy to confirm or exclude MPE when used alone. A multi-biomarker strategy, also encompassing the use of artificial intelligence algorithms, may be a valuable perspective for improving the diagnostic accuracy of MPE.

Clinical utility of pleural fluid YKL-40 as a marker of malignant pleural effusion

Pleural effusion is a common presenting feature of malignancy. Malignant pleural effusion is primarily diagnosed by pleural fluid cytology, pleural biopsy, and tumor markers. The glycoprotein YKL-40 is a new tumor marker that has shown to have a good diagnostic accuracy to detect malignant pleural effusion. However, there are only a few studies that have evaluated pleural fluid YKL-40 for detecting malignant pleural effusions. Hence, we conducted this study to evaluate the utility of pleural fluid YKL-40 to detect malignant pleural effusion. This is a cross-sectional study conducted between February 2016 and December 2017 in a tertiary care referral hospital. One hundred and forty-seven consecutive patients with pleural effusion were included in the study. These patients were divided into 3 groups, viz malignant, tuberculous, and parapneumonic pleural effusion, based on clinical features, radiological examination, and pleural fluid analysis. Pleural fluid YKL-40 levels were measured using enzyme-linked immunosorbent assay. Out of the 147 consecutive patients included in the study, 47 patients (31.97%) had malignant pleural effusion, 51 patients (34.69%) had tuberculous pleural effusion, and 49 patients (33.33%) had parapneumonic pleural effusion. The median pleural fluid YKL-40 level was higher in malignant pleural effusion (114.80 ng/mL) compared to tuberculous (93.17 ng/mL) and parapneumonic pleural effusion (89.87 ng/mL; P < 0.05). A diagnostic cut-off for pleural fluid YKL-40 value of 99.76 ng/mL detected malignant pleural effusion with 83% sensitivity, 87% specificity, positive predictive value (PPV) of 75%, negative predictive value (NPV) of 91.58%, and diagnostic accuracy of 85.71%. The level of pleural fluid YKL-40 is significantly elevated in malignant pleural effusion. In lymphocytic pleural effusions presenting with low adenosine deaminase levels and high YKL-40 levels, a thorough diagnostic search for malignancy is warranted.

The YKL-40 protein is a potential biomarker for COPD: a meta-analysis and systematic review

Background

Many studies have found that YKL-40 may play an important pathogenic role in COPD. However, the results of these studies were inconsistent. Therefore, we performed a systematic review and meta-analysis to investigate the role of YKL-40 in COPD.

Methods

We performed a systematic literature search in many database and commercial internet search engines to identify studies involving the role of YKL-40 in patients with COPD. The standardized mean difference (SMD) and Fisher’s Z-value with its 95% confidence interval (CI) were used to investigate the effect sizes.

Results

A total of 15 eligible articles including 16 case–control/cohort groups were included in the meta-analysis. The results indicated that the serum YKL-40 levels in patients with COPD were significantly higher than those in healthy controls (SMD =1.58, 95% CI =0.68–2.49, P=0.001), and it was correlated with lung function (pooled r=−0.32; Z=−0.33; P<0.001). The results of subgroup analysis found that the serum YKL-40 levels were statistically different between the exacerbation group and the stable group in patients with COPD (SMD =1.55, 95% CI =0.81–2.30, P<0.001). Moreover, the results indicated that the sputum YKL-40 levels in patients with COPD were also significantly higher than those in healthy controls (SMD =0.70, 95% CI =0.10–1.30, P=0.022).

Conclusion

The current study suggests that YKL-40 may be implicated in bronchial inflammation and remodeling in COPD and may be considered as a useful biomarker for COPD diagnosis and monitoring.

Expression of YKL-40 and MIP-1a proteins in exudates and transudates: biomarkers for differential diagnosis of pleural effusions? A pilot study

Background

YKL-40 is an extracellular matrix glycoprotein with a significant role in tissue inflammation and remodeling. MIP-1a has chemotactic and pro-inflammatory properties, and is induced by YKL-40 in several lung disorders. The aim of this study was to determine the levels of YKL-40 and MIP-1a in blood serum and pleural fluids of various pulmonary diseases, and to evaluate their potential role as differential diagnosis biomarkers.

Methods

We recruited 60 patients (age: 62.5 ± 20.6 years) with pleural effusions: 49 exudates and 11 transudates (T). Exudates were further classified based on the underlying disease: ten with tuberculosis (TB), 13 with lung cancer (LCa), 15 with metastatic cancer (MCa) of non-lung origin and 11 with parapneumonic (PN) effusions. YKL-40 and MIP-1a levels were measured by ELISA.

Results

Pleural YKL-40 levels (ng/ml) were similar among all patient groups (TB: 399 ± 36, LCa: 401 ± 112, MCa: 416 ± 34, PN: 401 ± 50, T: 399 ± 42, p = 0.92). On the contrary, YKL-40 was significantly lower in the serum of TB patients (TB: 58 ± 22, LCa: 212 ± 106, MCa: 254 ± 140, PN: 265 ± 140, T: 229 ± 123, p < 0.001). Pleural MIP-1a protein levels (ng/ml) were statistically lower only in patients with LCa (TB: 25.0 ± 20.2, LCa: 7.3 ± 6.0, MCa: 16.1 ± 14.9, PN: 25.4 ± 27.9, T: 18.5 ± 7.9, p = 0.012), a finding also observed in serum MIP-1a levels (TB: 17.1 ± 7.6, LCa: 9.4 ± 7.0, MCa: 28.7 ± 28.7, PN: 33.3 ± 24.0, T: 22.9 ± 8.7, p = 0.003).

Conclusions

Our data suggest that both YKL-40 and MIP-1a, particularly in serum, could prove useful for the differentiation of pleural effusions in clinical practice, especially of TB or LCa origin. However, large-scale studies are needed to validate these findings.

The role of chitin, chitinases, and chitinase-like proteins in pediatric lung diseases

Chitin, after cellulose, the second most abundant biopolymer on earth, is a key component of insects, fungi, and house-dust mites. Lower life forms are endowed with chitinases to defend themselves against chitin-bearing pathogens. Unexpectedly, humans were also found to express chitinases as well as chitinase-like proteins that modulate immune responses. Particularly, increased levels of the chitinase-like protein YKL-40 have been associated with severe asthma, cystic fibrosis, and other inflammatory disease conditions. Here, we summarize and discuss the potential role of chitin, chitinases, and chitinase-like proteins in pediatric lung diseases.

The clinical utility of pleural YKL-40 levels in diagnosing pleural effusions

BACKGROUND AND OBJECTIVE

Recent evidence suggests that YKL-40 is a relatively new biomarker of inflammation and it is involved in the pathogenesis of several pulmonary diseases. Details of serum and pleural YKL-40 in pleural effusions however, remain unknown. We aimed to assess whether serum and pleural YKL-40 is an accurate biomarker of pleural effusions.

METHODS

This clinical study was prospective, observational and cross-sectional. The concentrations of serum and pleural fluid YKL-40 and conventional pleural marker levels were measured in 80 subjects with pleural effusions, including 23 transudates caused by congestive heart failure (CHF), and 57 exudates including 23 parapneumonic, 22 malignant and 12 tuberculous pleural effusions (TBPEs).

RESULTS

Median pleural fluid YKL-40 levels were higher in exudates than in transudates (219.4 and 205.9 ng/mL, respectively, P<0.001). High pleural YKL-40 levels, with a cutoff value of >215 ng/mL, yielded a 73% sensitivity, 73% specificity, likelihood ratio 2.8 for diagnosing exudate, with an area under the curve of 0.770 [95% confidence intervals (CI): 0.657-0.884]. Pleural YKL-40/serum YKL-40 ratio >1.5 yielded a 75% sensitivity, 72% specificity and likelihood ratio 2.6 for diagnosing TBPE, with an area under the curve of 0.825 (95% CI: 0.710-0.940).

CONCLUSIONS

High concentrations of pleural YKL-40 level may help to differentiate exudate from transudate and a high pleural YKL-40/serum YKL-40 ratio may be helpful in seperating TBPE from non-tuberculous effusions.

Usefulness of plasma YKL-40 in management of community-acquired pneumonia severity in patients

Plasma YKL-40 level has been reported as playing a significant role in community-acquired pneumonia (CAP). However, the correlation between plasma level of YKL-40 and the severity of CAP has not been reported. This study identifies the relationship between plasma level changes of the YKL-40 gene in adult patients hospitalized with CAP. The ELISA was used to measure the plasma YKL-40 level from 61 adult CAP patients before and after antibiotic treatment and from 60 healthy controls. The plasma YKL-40 levels were significantly increased in patients with CAP compared to normal controls. Moreover, the plasma concentration of YKL-40 correlated with the severity of CAP based on the pneumonia severity index (PSI) score (r = 0.630, p < 0.001), the CURB-65 (confusion, uremia, respiratory rate, BP, age 65 years) score (r = 0.640, p < 0.001), the Acute Physiology And Chronic Health Evaluation II (APACHE II) score (r = 0.539, p < 0.001) and length of hospital stay (r = 0.321, p = 0.011), respectively. In conclusion, plasma YKL-40 may play a role in the diagnosis and clinical assessment of CAP severity, which could potentially guide the development of treatment strategies.