Flu indicates fludarabine; Bu, busulfan; Al, alemtuzumab; Mel, melphalan; Cy, cyclophosphamide; TLI, total lymphoid irradiation; ATG, anti-thymocyte globulin; ALG, anti-lymphocyte globulin; TBI, total body radiation; OS, overall survival; EFS, event-free survival; and TT, thiotepa.