Science Highlights
Published on August 03, 2026
Assessing mHAg-Specific Donor Treg in allo-HCT
by Blood
Pidala JA, Cieri N, Schell MJ, et al. Expanded Antigen-Specific Donor Regulatory T Cells for GVHD Prevention. Blood. 2026; (doi: 10.1182/blood.2025030663).
Scientists report promising early results from a novel approach for preventing graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (allo-HCT). The technique relies on expanded donor regulatory T cells (Treg) — specifically, minor histocompatibility antigen (mHAg)-specific Treg — to prevent GVHD in matched sibling donor allo-HCT. In a Phase I translational trial, researchers observed that Treg clones expanded in culture and, once infused, exhibited durable persistence, lineage fidelity, and in vivo expansion for at least 1 year post-transplant. None of the 15 study participants experienced dose-limiting toxicities, underscoring the favorable safety profile of expanded mHAg-specific donor Treg. The cumulative incidence of grade 2-4 acute GVHD at Day 100 was 13%, while the development of moderate/severe chronic GVHD was 6.7% at 1-year follow-up and 20% by 3 years. Overall survival reached 73%.
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