Hemophagocytic lymphohistiocytosis (HLH) in Syntaxin-11 deficient mice: T-cell exhaustion limits fatal disease

Tamara Kögl, Jürgen Müller, Birthe Jessen, Annette Schmitt-Graeff, Gritta Janka, Stephan Ehl, Udo zur Stadt and Peter Aichele


Syntaxin-11 (Stx11), an atypical member of the SNARE protein family, is part of the cytolytic machinery of T and NK cells and involved in the fusion of lytic granules with the plasmamembrane. Functional loss of syntaxin-11 in humans causes defective degranulation and impaired cytolytic activity of T and NK cells. Furthermore, patients with STX11 deficiency develop familial hemophagocytic lymphohistiocytosis type 4 (FHL4), a life-threatening disease of severe hyperinflammation. We established Stx11-deficient mice as an animal model for FHL4. Stx11-deficient mice exhibited severely reduced degranulation and cytolytic activity of CTL and NK cells and developed all clinical symptoms of hemophagocytic lymphohistiocytosis (HLH) after infection with lymphocytic choriomeningitis virus (LCMV). The HLH phenotype was further characterized by hyperreactive CD8 T cells and continuous IFNγ production. However, in contrast to perforin-deficient mice, which represent a model for FHL2, progression of HLH was not fatal. Survival of Stx11-deficient mice was determined by exhaustion of antigen-specific T cells, characterized by expression of inhibitory receptors, sequential loss of effector functions and finally T-cell deletion. Blockade of inhibitory receptors on T cells in Stx11-deficient mice converted non-fatal disease course into fatal HLH, identifying T-cell exhaustion as an important factor for determination of disease severity in HLH.

  • Submitted July 3, 2012.
  • Accepted November 4, 2012.