Allogeneic hematopoietic cell transplantation (HCT) is a curative therapy limited by graft-versus-host disease (GVHD). In preclinical studies and early-phase clinical studies enrichment of donor regulatory T cells (Tregs) appears to prevent GVHD and promote healthy immunity.We enrolled 44 patients on an open-label, single-center, phase 2 efficacy study investigating if a precision selected and highly purified Treg cell therapy manufactured from donor mobilized peripheral blood improves …