POST-TRANSPLANTATION IMMUNOSUPPRESSION: Patients receive cyclophosphamide IV over 1 hour on day 3 and mycophenolate mofetil orally (PO) thrice daily (TID) on days 4 to 40, followed by a taper until day 84 in the absence of GVHD. Patients also receive tacrolimus IV continuously or IV once daily (QD) over 1-2 hours or PO twice daily (BID) on days 4 to 84, followed by a taper until day 180 in the absence of GVHD.