Cytokines induced during chronic hepatitis B virus infection promote a pathway for NK cell-mediated liver damage

J Exp Med. 2007 Mar 19;204(3):667-80. doi: 10.1084/jem.20061287. Epub 2007 Mar 12.

Abstract

Hepatitis B virus (HBV) causes chronic infection in more than 350 million people worldwide. It replicates in hepatocytes but is non-cytopathic; liver damage is thought to be immune mediated. Here, we investigated the role of innate immune responses in mediating liver damage in patients with chronic HBV infection. Longitudinal analysis revealed a temporal correlation between flares of liver inflammation and fluctuations in interleukin (IL)-8, interferon (IFN)-alpha, and natural killer (NK) cell expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) directly ex vivo. A cross-sectional study confirmed these findings in patients with HBV-related liver inflammation compared with healthy carriers. Activated, TRAIL-expressing NK cells were further enriched in the liver of patients with chronic HBV infection, while their hepatocytes expressed increased levels of a TRAIL death-inducing receptor. IFN-alpha concentrations found in patients were capable of activating NK cells to induce TRAIL-mediated hepatocyte apoptosis in vitro. The pathogenic potential of this pathway could be further enhanced by the ability of the IFN-alpha/IL-8 combination to dysregulate the balance of death-inducing and regulatory TRAIL receptors expressed on hepatocytes. We conclude that NK cells may contribute to liver inflammation by TRAIL-mediated death of hepatocytes and demonstrate that this non-antigen-specific mechanism can be switched on by cytokines produced during active HBV infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Cells, Cultured
  • Cross-Sectional Studies
  • Cytokines / physiology*
  • Hepatitis B virus / immunology
  • Hepatitis B, Chronic / immunology*
  • Hepatitis B, Chronic / metabolism
  • Hepatitis B, Chronic / pathology
  • Humans
  • Interferon-alpha / blood
  • Interleukin-8 / blood
  • Killer Cells, Natural / immunology*
  • Killer Cells, Natural / virology
  • Liver / immunology
  • Liver / pathology*
  • Liver / virology*
  • Longitudinal Studies
  • Signal Transduction / immunology*

Substances

  • Cytokines
  • Interferon-alpha
  • Interleukin-8