title: Glycoprotein YKL-40: a novel biomarker of chronic graft-vs-host disease activity and severity?
abstract: OBJECTIVE
  To investigate whether increased YKL-40 levels positively correlate with graft-vs-host disease (cGVHD) activity and severity and if YKL-40 could serve as a disease biomarker.
  
  
  METHODS
  This case-control study was conducted at the University Hospital Centre Zagreb from July 2013 to October 2015. 56 patients treated with hematopoietic stem cell transplantation (HSCT) were included: 35 patients with cGVHD and 21 without cGVHD. There was no difference between groups in age, sex, median time from transplant to study enrollment, intensity of conditioning, type of donor, or source of stem cells. Blood samples were collected at study enrollment and YKL-40 levels were measured with ELISA. Disease activity was estimated using Clinician's Impression of Activity and Intensity of Immunosuppression scales and disease severity using Global National Institutes of Health (NIH) score.
  
  
  RESULTS
  YKL-40 levels were significantly higher in cGVHD patients than in controls (P=0.003). The difference remained significant when patients with myelofibrosis were excluded from the analysis (P=0.017). YKL-40 level significantly positively correlated with disease severity (P<0.001; correlation coefficient 0.455), and activity estimated using Clinician's Impression of Activity (P=0.016; correlation coefficient 0.412) but not using Intensity of Immunosuppression (P=0.085; correlation coefficient 0.296).
  
  
  CONCLUSIONS
  YKL-40 could be considered a biomarker of cGVHD severity and activity. However, validation in a larger group of patients is warranted, as well as longitudinal testing of YKL-40 levels in patients at risk of developing cGVHD.
authors.affiliation: Nadira Duraković, University Hospital Centre Zagreb, Dept of Internal Medicine, Division of Hematology, Kišpatićeva 12, 10000 Zagreb, Croatia, nadira@mef.hr.
authors.forename: Nadira
authors.initials: N
authors.lastname: Duraković
authors.forename: Ivan
authors.initials: I
authors.lastname: Krečak
authors.forename: Zinaida
authors.initials: Z
authors.lastname: Perić
authors.forename: Milan
authors.initials: M
authors.lastname: Milošević
authors.forename: Lana
authors.initials: L
authors.lastname: Desnica
authors.forename: Dražen
authors.initials: D
authors.lastname: Pulanić
authors.forename: Iskra
authors.initials: I
authors.lastname: Pusic
authors.forename: Vesna
authors.initials: V
authors.lastname: Kušec
authors.forename: Radovan
authors.initials: R
authors.lastname: Vrhovac
authors.forename: Steven Z
authors.initials: SZ
authors.lastname: Pavletic
authors.forename: Damir
authors.initials: D
authors.lastname: Nemet
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood*; D016022:Case-Control Studies; D002648:Child; D000071451:Chitinase-3-Like Protein 1 / Q000097:blood*; D002908:Chronic Disease; D005260:Female; D006086:Graft vs Host Disease / Q000097:blood / Q000175:diagnosis* / Q000473:pathology; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D015415:Biomarkers; C084533:CHI3L1 protein, human; D000071451:Chitinase-3-Like Protein 1