Familial hemophagocytic lymphohistiocytosis hepatitis is mediated by IFN-γ in a predominantly hepatic-intrinsic manner

PLoS One. 2022 Jun 7;17(6):e0269553. doi: 10.1371/journal.pone.0269553. eCollection 2022.

Abstract

Interferon gamma (IFN-γ) is the main cytokine driving organ dysfunction in Familial Hemophagocytic Lymphohistiocytosis (FHL). Blockade of IFN-γ pathway ameliorates FHL hepatitis, both in animal models and in humans with FHL. Hepatocytes are known to express IFN-γ receptor (IFN-γ-R). However, whether IFN-γ induced hepatitis in FHL is a lymphocyte or liver intrinsic response to the cytokine has yet to be elucidated. Using a IFNgR-/- bone marrow chimeric model, this study showed that non-hematopoietic IFN-γ response is critical for development of FHL hepatitis in LCMV-infected Prf1-/- mice. Lack of hepatic IFN-γ responsiveness results in reduced hepatitis as measured by hepatomegaly, alanine aminotransferase (ALT) levels and abrogated histologic endothelial inflammation. In addition, IFN-γ non-hematopoietic response was critical in activation of lymphocytes by soluble interleukin 2 receptor (sIL-2r) and recruitment of CD8+ effector T lymphocytes (CD8+ CD44hi CD62Llo) (Teff) and inflammatory monocytes. Lastly, non-hematopoietic IFN-γ response results in increased hepatic transcription of type 1 immune response and oxidative stress response pathways, while decreasing transcription of genes involved in extracellular matrix (ECM) production. In summary, these findings demonstrate that there is a hepatic transcriptional response to IFN-γ, likely critical in the pathogenesis of FHL hepatitis and hepatic specific responses could be a therapeutic target in this disorder.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • CD8-Positive T-Lymphocytes
  • Hepatitis* / pathology
  • Interferon-gamma / metabolism
  • Lymphohistiocytosis, Hemophagocytic* / genetics
  • Lymphohistiocytosis, Hemophagocytic* / pathology
  • Mice

Substances

  • Interferon-gamma