Although rodent graft-versus-host disease (GVHD) models have suggested that indoleamine 2,3-dioxygenase (IDO) is a critical regulator of gastrointestinal GVHD, parallel human studies on IDO expression have not been reported. IDO expression was assessed in 20 patients who underwent duodenal biopsy. IDO was upregulated in epithelial cells. In situ analyses reveal that macrophages and dendritic cells stain positive for IDO, but that most of the IDO + cells were a novel population of CD3 +CD4 +IDO + cells. The proportion of CD4 +IDO + T cells was significantly higher in patients with moderate GVHD. In situ regulatory T cell and Th17 numbers correlated with overall severity. Although needing confirmatory results from larger sample sets, these data are consistent with the hypothesis that IDO is involved in regulating gastrointestinal GVHD.
Bibliographical noteFunding Information:
Financial disclosure: This research was supported by a grant from the European Commission StemDiagnositics Contract No. LSHB-CT-2007-037703 , and by Institut National du Cancer and Cancéropôle Ile de France, Conseil régional Ile de France, Agence de Biomédecine, and NIH Grants R01 AI34495, R01 CA 72 669, and R37 HL56067 .
- Graft-vs-host disease
- Regulatory T cells