Serum and BALF YKL-40 levels are predictors of survival in idiopathic pulmonary fibrosis

Respir Med. 2011 Jan;105(1):106-13. doi: 10.1016/j.rmed.2010.09.012.


Background: The chitinase-like protein YKL-40 is a serum biomarker in diseases with fibrosis, inflammation and tissue remodelling. Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease that is hallmarked by these processes. The aim of this study was to investigate the potential of YKL-40 as a prognostic biomarker for survival in IPF patients.

Methods: Serum and bronchoalveolar lavage fluid (BALF) levels of YKL-40 at the time of diagnosis and a promoter polymorphism in CHI3L1, the gene encoding YKL-40, were determined in 85 IPF patients and 126 controls. The relationship between YKL-40 levels and clinical parameters was evaluated. Kaplan-Meier and Cox regression analyses were used to examine the association between YKL-40 levels and survival.

Results: Serum and BALF YKL-40 levels were significantly higher in patients than in healthy controls (p < 0.001). The - 329 A/G polymorphism had a significant influence on BALF YKL-40 levels and the influence on serum YKL-40 levels showed a trend towards significance in IPF patients. IPF patients with high (> 79 ng/ml) serum or high BALF YKL-40 (> 17 ng/ml) levels had significantly shorter survival than those with low YKL-40 levels in serum or BALF. In patients with both low serum and low BALF YKL-40 levels no IPF related mortality was observed. Cox regression modelling showed that there were no confounding factors.

Conclusions: The - 329 polymorphism was associated with serum and BALF YKL-40 levels in IPF patients. High serum and BALF YKL-40 levels are associated with poor survival in IPF patients and could be useful prognostic markers for survival in IPF.

MeSH terms

  • Adipokines
  • Adult
  • Aged
  • Biomarkers / analysis
  • Biomarkers / metabolism
  • Bronchoalveolar Lavage Fluid / chemistry*
  • Chitinase-3-Like Protein 1
  • Female
  • Glycoproteins / analysis
  • Glycoproteins / genetics
  • Glycoproteins / metabolism*
  • Humans
  • Idiopathic Pulmonary Fibrosis / metabolism*
  • Idiopathic Pulmonary Fibrosis / mortality
  • Lectins / analysis
  • Lectins / genetics
  • Lectins / metabolism*
  • Male
  • Middle Aged
  • Netherlands / epidemiology
  • Proportional Hazards Models


  • Adipokines
  • Biomarkers
  • CHI3L1 protein, human
  • Chitinase-3-Like Protein 1
  • Glycoproteins
  • Lectins