Nonmyeloablative Haploidentical Peripheral Blood Mobilized Hematopoietic Precursor Cell Transplantation for Sickle Cell Disease

Background: Peripheral blood stem cell transplantation procedures are used for people with sickle cell disease. Researchers want to improve the success and reduce the complications for these procedures. This might allow more people to have a transplant. Objective: To see if a new transplant regime is effective, safe and well tolerated in people with sickle cell disease. Eligibility: Adults at least 18 years old with sickle cell disease and certain complications. A relative who is a half tissue match. Design: Participants will be screened with medical history, physical exam, and blood tests. Recipients will also have: * Heart, lung, and mental health tests * Chest x-rays * Bone marrow taken from the pelvic bone * Eyes and teeth checked Recipients will have a large central line inserted into a vein for up to 6 months. Donors will have their veins tested and have an IV inserted for 1 day or on rare occasions 2 days. Donors will get a drug to activate bone marrow. It will be injected for about 6 days. Donors will have at least 1 five-hour procedure where bone marrow stem cells will be collected. Blood will be taken from a vein in one arm or in rare cases from a groin vein and put through a machine. Some blood will be saved and the rest will be returned. Stem cells will be taken from the saved blood in a lab and frozen until ready to give to the recipient. Recipients will have: * Stems cells collected and frozen * Hygiene lessons * Bone density scans * Low-dose radiation * Drugs for their immune system * Donor cells infused through their central line * Transfusions After about 30 days, recipients will leave the hospital. They must stay near NIH for 3 months after the transplant and have frequent visits. After returning home, they will have 8 visits over 5 years, then be contacted yearly.