Patients undergo pretargeted radioimmunotherapy comprising a test dose of BC8-SA conjugate intravenously (IV) on day -22 and indium In 111(111In)-DOTA-biotin IV on day -20, followed by a therapy dose of BC8-SA conjugate IV on day -14 and 90Y-DOTA-biotin IV on day -12. Patients receive fludarabine phosphate IV on days -4 to -2. Patients undergo TBI and then peripheral blood stem cell transplantation on day 0. Patients with matched related donors receive cyclosporine IV on days -3 to 56 and taper to day 180 and mycophenolate mofetil orally (PO) twice daily (BID) on days 0-27. Patients with matched unrelated donors receive cyclosporine IV on days -3 to 100 and taper to day 180 and mycophenolate mofetil PO thrice daily (TID) on days 0-40 and taper to day 96.