This trial will use two cord blood units for transplantation using a reduced intensity
regimen rather than using intense doses of chemotherapy and radiation therapy. Two cord blood
units (double cord blood) are being used, as the numbers of blood cells in one unit are too
few to allow successful growth of these cells.
Because the risk of infection, particularly virus infection, is high after double cord blood
transplant, this study seeks to reduce the rise of virus infection by using a reduced
intensity regimen without a medicine called antithymocyte globulin (ATG), as used in prior
cord blood transplants. Subjects will receive two chemotherapy drugs, melphalan and
fludarabine, and low dose of total body radiation (one treatment) instead of the ATG. The
number of patients with virus infections in this study will be compared to our prior
experience using the ATG.