Naive T Cell Depletion for Preventing Chronic Graft-versus-Host Disease in Children and Young Adults With Blood Cancers Undergoing Donor Stem Cell Transplant

This study is testing a new method of preparing stem cell transplants for children and young adults with blood cancers. The technique removes certain immune cells (called naive T cells) from the donor's stem cells before transplant, with the aim of reducing a serious complication called chronic graft-versus-host disease — where the donor's immune cells attack the patient's body. **You may be eligible if...** - You have a blood cancer such as acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), or myelodysplastic syndrome (MDS), in remission or with limited disease - You are a candidate for a stem cell transplant from a donor - You meet the age, health, and disease-specific criteria assessed by the study team **You may NOT be eligible if...** - Your leukemia is not in adequate remission - You have active, uncontrolled infection - You have severe organ problems that would make transplant too risky - You do not have a suitable donor identified Talk to your doctor to see if this trial is right for you.