Cord Blood Stem Cell TransplantationFetal BloodTransplantation, HomologousSpinal CordHematopoietic Stem Cell TransplantationGraft vs Host DiseaseBone Marrow TransplantationSpinal Cord InjuriesGraft SurvivalTissue DonorsUmbilical CordTransplantation ConditioningGraft RejectionBlood BanksKidney TransplantationTransplantation ChimeraInfant, NewbornHistocompatibility TestingHematologic NeoplasmsAntigens, CD34Hematopoietic Stem CellsT-LymphocytesIsoantigens