The novel immunoregulatory molecule FGL2: a potential biomarker for severity of chronic hepatitis C virus infection

J Hepatol. 2010 Oct;53(4):608-15. doi: 10.1016/j.jhep.2010.04.020. Epub 2010 Jun 17.


Background & aims: 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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Biomarkers / blood
  • Case-Control Studies
  • Female
  • Fibrinogen / analysis*
  • Fibrinogen / immunology
  • Hepatitis C, Chronic / blood*
  • Hepatitis C, Chronic / immunology
  • Humans
  • Liver Diseases, Alcoholic / blood*
  • Liver Diseases, Alcoholic / immunology
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Sensitivity and Specificity
  • Severity of Illness Index


  • Biomarkers
  • FGL2 protein, human
  • Fibrinogen