Donor Lymphocyte Infusion Post Transplant

Background: People with blood cancers often receive blood or bone marrow transplants. But even with these treatments, the risk of relapse is high. Researchers want to see if giving the transplant recipient an infusion of lymphocytes (a type of white blood cell) from their transplant donor early after the transplant can reduce that risk. Objective: To learn if giving donor lymphocytes early after a transplant will help reduce the risk of relapse for people with certain blood cancers. Eligibility: Adults aged 18-65 with high-risk leukemia, lymphoma, myelodysplastic syndrome, or multiple myeloma that does not respond well to standard treatments and/or has a high risk of relapse. Healthy potential bone marrow and lymphocyte donor relatives aged 12 and older are also needed. Design: Participants will be screened with: Physical exam Blood and urine tests Spinal tap Eye exam Dental exam Heart and lung tests Imaging scans. A radioactive substance may be injected in their arm if a PET scan is needed. Bone marrow aspiration and biopsy Some screening tests will be repeated during the study. Participants will stay at the NIH hospital for about 4 weeks. They will receive a central venous catheter. They will get chemotherapy and other drugs starting 6 days before transplant. Then they will have their transplant. They will receive donor white blood cells 7 days later. They will give blood, bone marrow, urine, and stool samples for research. They must stay near NIH for at least 100 days after transplant. Participants will have periodic follow-up visits for 5 years. Healthy donors will have 2-3 visits. They will give blood, bone marrow, white blood cells, and stool samples for research. Participation will last for 5 years....