2.3 Conditioning regimen and stem cell collection
All patients received a myeloablative conditioning regimen (MAC) without
in vitro T-cell depletion. The conditioning regimens used in our center
were based on BU and total body irradiation (TBI). For patients who
received haploidentical HSCT, the conditioning regimen was modified to
include the following: BUCY+ATG (thymoglobulin) consisting of cytarabine
(4 g/m2 per day in haploidentical HSCT) intravenously
on days -10 to -9; busulfan (3.2 mg/kg per day, intravenously on days -8
to -6); cyclophosphamide (CY, 1.8 g/m2 per day) intravenously on days -5
to -4; Me-CCNU (250 mg/m2), orally once on day -3; and thymoglobulin
(ATG, Sang Stat, Lyon, France; 2.5 mg/kg per day) intravenously for 4
consecutive days from days -5 to -2. Patients undergoing HLA-matched
sibling donor HSCT received hydroxycarbamide (80 mg/kg) orally on day
-10 and a lower dose of cytarabine (2 g/m2 per day) on day -9, but
otherwise, these patients followed an identical regimen to
haploidentical patients, without ATG. The TBI-based conditioning regimen
was composed of the following: TBI (770 cGy for a single dose) on days
-6 and cyclophosphamide (CY, 1.8 g/m2 per day) intravenously on days -5
to -4; and Me-CCNU (250 mg/m2), orally once on day -3. ATG was used for
patients who received haplo-HSCT, and the dosage and time were
consistent with the above description. All subjects received fresh
granulocyte colony-stimulating factor (G-CSF)-mobilized bone marrow (BM)
and peripheral blood cells. Patients also received prophylactic drugs to
prevent infection by fungi and viruses.