 NONMYELOABLATIVE CONDITIONING REGIMEN: Patients receive alemtuzumab intravenously IV over 6 hours once daily on days -6, -5, and -4 OR days -5 and -4 and fludarabine phosphate IV over 30 minutes on days -4, -3, and -2. Patients also undergo low-dose total-body irradiation TBI on day 0. 