ARM II: Patients undergo HCT at day 0. Patients with an HLA-matched unrelated donor receive cyclosporine PO BID on days 5-96 then tapered to day 150, sirolimus PO QD on days 5-150 then tapered to day 180, and cyclophosphamide intravenously (IV) on days 3 and 4. Patients with an HLA-mismatched donor receive cyclosporine PO BID on days 5-150 then tapered to day 180, sirolimus PO QD on days 5-180 then tapered to day 365, and cyclophosphamide IV on days 3 and 4.