Predictive factors and impact of full donor T-cell chimerism after reduced intensity conditioning allogeneic stem cell transplantation.

This study investigated the kinetics of CD3+-T cell chimerism (TCC) in 102 patients receiving reduced intensity conditioning allogeneic stem cell transplantation (RIC-allo-SCT) from an HLA-identical sibling. Patients with full donor TCC at day 30 had a higher incidence of grade 2-4 acute GVHD compared to patients in mixed TCC (cumulative-incidence, 61% vs. 35%; p=0.01). The delayed establishment of full donor TCC in myeloid malignancies was associated with a higher incidence of relapse (40% vs. 0; p=0.002), suggesting that monitoring of the kinetics of TCC is mandatory after RIC-allo-SCT.