title: Serum YKL-40 and interleukin 6 levels in Hodgkin lymphoma.
abstract: OBJECTIVE
  Serum levels of the inflammatory markers YKL-40 and interleukin 6 (IL-6) are increased in many conditions, including cancers. We examined serum YKL-40 and IL-6 levels in patients with Hodgkin lymphoma, a tumor with strong immunologic reaction to relatively few tumor cells, especially in nodular sclerosis Hodgkin lymphoma.
  
  
  METHODS
  We analyzed Danish and Swedish patients with incident Hodgkin lymphoma (N=470) and population controls from Denmark (n=245 for YKL-40; n=348 for IL-6). Serum YKL-40 and IL-6 levels were determined by ELISA, and log-transformed data were analyzed by linear regression, adjusting for age and sex.
  
  
  RESULTS
  Serum levels of YKL-40 and IL-6 increased in Hodgkin lymphoma patients compared with controls (YKL-40, 3.6-fold; IL-6, 8.3-fold; both, P<0.0001). In pretreatment samples from pretreatment Hodgkin lymphoma patients (n=176), levels were correlated with more advanced stages (P(trend), 0.0001 for YKL-40 and 0.013 for IL-6) and in those with B symptoms; however, levels were similar in nodular sclerosis and mixed cellularity subtypes, by EBV status, and in younger (<45 years old) and older patients. Patients tested soon after treatment onset had significantly lower levels than pretreatment patients; however, even >or=6 months after treatment onset, serum YKL-40 and IL-6 levels remained significantly increased compared with controls. In patients who died (n=12), pretreatment levels for YKL-40 and IL-6 were higher than in survivors, although not statistically significantly.
  
  
  CONCLUSIONS
  Serum YKL-40 and IL-6 levels were increased in untreated Hodgkin lymphoma patients and those with more advanced stages but did not differ significantly by Hodgkin lymphoma histology. Following treatment, serum levels were significantly lower.
authors.affiliation: Department of Epidemiology Research, State Serum Institute, Copenhagen, Denmark. rjb@ssi.dk
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Biggar
authors.forename: Julia S
authors.initials: JS
authors.lastname: Johansen
authors.forename: Karin Ekström
authors.initials: KE
authors.lastname: Smedby
authors.forename: Klaus
authors.initials: K
authors.lastname: Rostgaard
authors.forename: Ellen T
authors.initials: ET
authors.lastname: Chang
authors.forename: Hans-Olov
authors.initials: HO
authors.lastname: Adami
authors.forename: Bengt
authors.initials: B
authors.lastname: Glimelius
authors.forename: Daniel
authors.initials: D
authors.lastname: Molin
authors.forename: Stephen
authors.initials: S
authors.lastname: Hamilton-Dutoit
authors.forename: Mads
authors.initials: M
authors.lastname: Melbye
authors.forename: Henrik
authors.initials: H
authors.lastname: Hjalgrim
mesh_terms: D054392:Adipokines; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D000071451:Chitinase-3-Like Protein 1; D005260:Female; D006023:Glycoproteins / Q000097:blood*; D006689:Hodgkin Disease / Q000097:blood*; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D037102:Lectins; D008297:Male; D008875:Middle Aged; D011379:Prognosis
chemical_list: D054392:Adipokines; D014408:Biomarkers, Tumor; C084533:CHI3L1 protein, human; D000071451:Chitinase-3-Like Protein 1; D006023:Glycoproteins; D015850:Interleukin-6; D037102:Lectins