Absence of inducible costimulator on alloreactive T cells reduces graft versus host disease and induces Th2 deviation Academic Article uri icon


MeSH Major

  • Antigens, Differentiation, T-Lymphocyte
  • Graft vs Host Disease
  • Lymphocyte Activation
  • T-Lymphocytes
  • Th2 Cells


  • Inducible costimulator (ICOS) is expressed on activated and memory T cells and is involved in the regulation of cytokine production. We studied the role of ICOS on alloreactive T cells in graft versus host disease (GVHD) and determined that ICOS expression was up-regulated on alloreactive T cells in recipients of an allogeneic hematopoietic stem cell transplantation (allo-HSCT) with GVHD. We compared ICOS-/- T cells with wild-type (WT) T cells in 2 GVHD models. In both models, recipients of ICOS-/- T cells demonstrated significantly less GVHD morbidity and mortality, which was associated with less intestinal and hepatic GVHD but increased cutaneous GVHD. In addition, recipients of ICOS-/- donor T cells displayed a slight decrease in graft versus leukemia (GVL) activity. Further analysis of alloreactive ICOS-/- T cells showed no defect in activation, proliferation, cytotoxicity, and target organ infiltration. Recipients of ICOS-/- T cells had decreased serum levels of interferon-gamma (IFN-gamma), while interleukin-4 (IL-4) and IL-10 levels were increased, suggesting that alloreactive ICOS-/- T cells are skewed toward T helper-2 (Th2) differentiation. These data suggest a novel role for ICOS in the regulation of Th1/Th2 development of activated T cells. In conclusion, alloreactive ICOS-/- donor T cells induce less GVHD due to a Th2 immune deviation while GVL activity is slightly diminished.

publication date

  • November 2005



  • Academic Article



  • eng

PubMed Central ID

  • PMC1895338

Digital Object Identifier (DOI)

  • 10.1182/blood-2005-01-0410

PubMed ID

  • 15956289

Additional Document Info

start page

  • 3285

end page

  • 92


  • 106


  • 9