CR indicates complete remission; PR, partial remission; SD, stable disease; PD, progressive disease; Flu, fludarabine; Bu, busulfan; TBI, total body irradiation; NRM, nonrelapse mortality; OS, overall survival; PFS, progression-free survival; TRM, transplantation-related mortality; RFS, relapse-free survival; AML, acute myelogenous leukemia; MDS, myelodysplastic syndrome; CLL, chronic lymphocytic leukemia; CML, chronic myeloid leukemia; ALL, acute lymphoblastic leukemia; ecGVHD, extensive chronic GVHD; and d, days.