Early studies of allogeneic stem cell transplants found an interesting effect—transplanted immune cells had a robust response to tumor cells. This response resulted from differences in minor mHA antigens between the donor and recipient. As a result, now leukemia patients can limit the toxic chemotherapy used to control their disease. Another therapy, the use of donor lymphocytes for the prevention of relapse, is as effective as an anti-tumor agent. This is especially helpful if the original transplant was conditioned to remove donor T-cells.
