In some patients who need a blood stem cell transplant, a well-matched H (human) L (leukocyte) A (antigen)-compatible donor cannot be found in a timely fashion. HLA antigens are proteins expressed on the surface of all cells other than red blood cells. Transplant outcome is generally much better when the patient and donor are well HLA-matched. Doctors in this study are trying to develop ways to make transplants from HLA-partially matched donors as safe and effective as transplants from HLA-matched donors.
Patients with different diseases (for example, leukemia, lymphoma, myelodysplastic syndrome, bone marrow failure, or immunodeficiency diseases) who need a hematopoietic blood stem cell transplant but who don’t have an HLA-matched donor are eligible. In this study, the patient will receive blood stem cells from two different related donors, each of whom shares one-half of the patient’s HLA type. T cells from the donor graft are removed to try and prevent an inflammatory reaction in the patient called graft-versus-host disease (GvHD). GvHD is caused by T cells in the graft which recognize the patient¿s cells as different.
Doctors hope that this approach can be used without increasing the risk of side effects, that it can improve a patient’s recovery after transplantation, and that it increases the effect that a donor’s immune cells may have in helping to rid the patient’s body of any lingering cancer cells.