title: The novel immunoregulatory molecule FGL2: a potential biomarker for severity of chronic hepatitis C virus infection.
abstract: OBJECTIVE
  This report describes the use of a novel sensitive and specific ELISA for the measurement of human fibrinogen-like protein 2 (FGL2/fibroleukin), a novel effector of natural regulatory T (Treg) cells, to predict the course of chronic hepatitis C viral infection (HCV).
  
  
  METHODS
  Plasma levels of FGL2 were measured in HCV patients and compared to healthy controls and to patients with alcoholic liver disease.
  
  
  RESULTS
  FGL2 levels were significantly higher in HCV patients (84.3+/-89.1 ng/ml, n=80) compared to healthy controls (36.4+/-21.9 ng/ml, n=30, p<0.001), to a subset of patients who cleared HCV following anti-viral treatment (16.6+/-19.7 ng/ml, n=32, p<0.001), and to patients with inactive alcoholic liver disease (18.8+/-17.4 ng/ml, n=24, p<0.001). Among HCV patients, plasma levels of FGL2 correlated significantly with the stage of fibrosis (p=0.001) and were significantly higher in patients with cirrhosis (164.1+121.8 ng/ml, n=60) compared to non-cirrhotics (57.7+/-52.8 ng/ml, n=20, p=0.001). Genotype 1 patients had significantly higher levels of FGL2 (98.1+/-100.3 ng/ml, n=60) compared to patients with genotype 2/3 (41.5+/-38.6 ng/ml, n=20, p=0.0008). Patients with genotype 2/3 had FGL2 levels similar to healthy controls (41.5+/-38.6 vs. 36.41+/-21.9 ng/ml, p=ns). Infiltrating lymphocytes in liver biopsies of HCV patients were positive for either FGL2 or FoxP3 (a marker of Treg cells) or expressed both markers.
  
  
  CONCLUSIONS
  This report documents the development of a sensitive ELISA for measurement of plasma levels of FGL2 an effector Treg cells, which correlates with the severity of HCV infection.
authors.affiliation: Multi Organ Transplant Program, University Health Network, University of Toronto, Toronto, Canada.
authors.forename: Katharina
authors.initials: K
authors.lastname: Foerster
authors.forename: Ahmed
authors.initials: A
authors.lastname: Helmy
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhu
authors.forename: Ramzi
authors.initials: R
authors.lastname: Khattar
authors.forename: Oyedele A
authors.initials: OA
authors.lastname: Adeyi
authors.forename: Kit Man
authors.initials: KM
authors.lastname: Wong
authors.forename: Itay
authors.initials: I
authors.lastname: Shalev
authors.forename: David A
authors.initials: DA
authors.lastname: Clark
authors.forename: Pui-Yuen
authors.initials: PY
authors.lastname: Wong
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Heathcote
authors.forename: Melville J
authors.initials: MJ
authors.lastname: Phillips
authors.forename: David R
authors.initials: DR
authors.lastname: Grant
authors.forename: Eberhard L
authors.initials: EL
authors.lastname: Renner
authors.forename: Gary A
authors.initials: GA
authors.lastname: Levy
authors.forename: Nazia
authors.initials: N
authors.lastname: Selzner
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D005340:Fibrinogen / Q000032:analysis* / Q000276:immunology; D019698:Hepatitis C, Chronic / Q000097:blood* / Q000276:immunology; D006801:Humans; D008108:Liver Diseases, Alcoholic / Q000097:blood* / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; C095202:FGL2 protein, human; D005340:Fibrinogen