title: YKL-40 protein correlates with the phenotype of asthma.
abstract: OBJECTIVE
  YKL-40 is a chitinase-like protein found to correlate with asthma as well as numerous infectious and autoimmune diseases or cancer. The aim of the present study was to investigate the role of YKL-40 as a possible marker of asthma and its associations with factors differentiating phenotypes of asthma.
  
  
  METHODS
  The study group comprised 167 patients, including 116 women and 51 men aged 18-88 years with chronic asthma. The control group comprised 81 healthy individuals, including 50 women and 31 men aged 19-86 years. In every participant, medical history was taken; spirometry and skin prick tests were performed. YKL-40 was determined in sera by means of ELISA test.
  
  
  RESULTS
  Mean serum YKL-40 level was 59.7 ng/ml (53.6-65.7 ng/ml; 95% CI) with significant difference between asthmatics and healthy controls (mean values: 66.8 ± 53.8 vs. 44.9 ± 29.4 ng/ml; p < 0.001). In asthmatics, the level was significantly higher in subgroup with poor control of symptoms and exacerbations (91.8 ± 57.1 ng/ml) compared to stable asthmatics (59.6 ± 50.8 ng/ml; p < 0.001) as well as in atopic compared to non-atopic asthmatics (77.2 ± 53.9 vs. 61.1 ± 57.8 ng/ml; p < 0.001). Mean YKL-40 level in obese asthmatics was 135.6 ng/ml compared to 50.0 ng/ml in non-obese (p < 0.001). When phenotypes of early-onset atopic, late-onset non-atopic, and obesity-related asthma were compared, YKL-40 levels were 80.62 ± 46.9, 51.5 ± 24.9, and 168.1 ± 71.5 ng/ml, respectively (p < 0.05).
  
  
  CONCLUSIONS
  Although YKL-40 is not a specific marker for asthma, it correlates with some clinical features such as exacerbation, level of control, atopy, and obesity.
authors: Department of Allergology, Medical University of Gdansk, Ul. Debinki 7, 80-952, Gdansk, Poland, specjalski@gumed.edu.pl.
authors: Krzysztof
authors: K
authors: Specjalski
authors: Marta
authors: M
authors: Chełmińska
authors: Ewa
authors: E
authors: Jassem
mesh_terms: D054392:Adipokines / Q000097:blood*; D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D001249:Asthma / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D000071451:Chitinase-3-Like Protein 1; D018450:Disease Progression; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000097:blood* / Q000150:complications; D037102:Lectins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000150:complications; D010641:Phenotype; D055815:Young Adult
chemical_list: D054392:Adipokines; D015415:Biomarkers; C084533:CHI3L1 protein, human; D000071451:Chitinase-3-Like Protein 1; D037102:Lectins