ARM I (transplant): Patients receive fludarabine intravenously (IV) on days -4 to -2. Patients undergo total-body irradiation on day 0. Patients then undergo peripheral blood stem cell transplantation on day 0. Patients receive GVHD prophylaxis comprising tacrolimus orally (PO) twice daily on days -3 to 180 and taper and mycophenolate mofetil PO three times daily on days 0-28 and then twice daily until day 180 and taper.