Harnessing dendritic cells to improve allogeneic hematopoietic cell transplantation outcome

In clinical practice, hematopoietic cell transplantation (HCT) is now recognized as a powerful means of delivering effective cellular immunotherapy for malignant and non-malignant diseases. In patients with severe hematological malignancies, the success of allogeneic HCT is largely based on immunologic graft-versus-tumor (GVT) effects mediated by allogeneic T lymphocytes present in the graft. Unfortunately, this beneficial effect is counterbalanced by the occurrence of graft versus host reactions directed against normal host tissues resulting in graft versus host disease (GVHD), a potentially life-threatening complication that limits the success of allogeneic HCT. Therefore, while preserving beneficial GVT effects, a major objective in allogeneic HCT is the prevention of GVHD. Studies in the last decade revealed the central role of dendritic cells and macrophages in modulating graft versus host immune reactions after allogeneic HCT. In this review, we summarize recent progress and potential new therapeutic avenues using dendritic cell-based strategies to improve allogeneic HCT outcome.