Biomarkers for acute and chronic graft-versus-host disease in regulatory T cells.

Despite improvements in the prevention and treatment of graft-versus-host disease (GvHD) this allogeneic immune response is still one of major complications following allogeneic stem cell transplantation (SCT). Identification of patients at risk for the development of acute and chronic GvHD would facilitate early intervention and thus improve overall survival. Diagnostic biomarkers identified in plasma are largely associated with T cell immune responses. Whereas donor effector T cells promote allogeneic immune responses, regulatory T cells (Tregs) may prevent GvHD by suppression of these alloreactive donor T cells. Therefore, we analyzed molecules associated with Tregs with respect to their potential predictive and prognostic impact on the development of acute and chronic GvHD. For this purpose, the Treg transcriptomes of patients with and without acute/chronic GvHD resulting from dynamical whole genome profiles of CD4(+)CD25(hi)CD127(lo/-) Tregs have been studied for potential GvHD biomarkers. We could identify potential biomarkers for acute/chronic GvHD like the activation marker phosphatidyl-5-kinase-gamma PIP5Kγ, FAS, CD44, CD69, and cell cycle regulators like cyclin A2, B1 and E2. Most importantly, the IKAROS transcription factor Eos, relevant for suppressive Treg function, might be relevant for the prediction of GvHD development. In addition markers like ANK3 (ankyrin), S100A8 and VCAN are indicative for acute GvHD, while IFIT3, IFI44 and IFIT1 are potential biomarkers for chronic GvHD. The identified markers have to be validated prospectively and might help to monitor and guide preventive immune intervention studies, especially adoptive donor Treg cell transfer.