Yttrium Y 90 Ibritumomab Tiuxetan, Fludarabine, Radiation Therapy, and Donor Stem Cell Transplant in Treating Patients With Relapsed or Refractory Non-Hodgkin's Lymphoma

PRIMARY OBJECTIVES: I. To assess the feasibility, safety, and potential efficacy of treating patients with B-Cell non-Hodgkin lymphoma (NHL) with 90Y-ibritumomab tiuxetan, combined with HLA-matched related or unrelated donor hematopoietic cell transplantation. OUTLINE: Patients receive rituximab intravenously (IV) followed by, no more than 4 hours later, indium In 111 ibritumomab tiuxetan (for imaging) IV over 10 minutes on day -21. Patients undergo gamma camera imaging on day -19. Patients receive rituximab IV followed by, no more than 4 hours later, yttrium Y 90 ibritumomab tiuxetan IV over 10 minutes on day -14. Patients also receive fludarabine phosphate IV over 30-60 minutes on days -7 to -5 and undergo low-dose total-body irradiation (TBI) on day 0. After TBI, patients undergo allogeneic peripheral blood stem cell transplantation (PBSCT) on day 0. Patients who undergo PBSCT from a related donor receive oral cyclosporine twice daily on days -3 to 56 followed by a taper to day 180 in the absence of graft-versus-host disease (GVHD). These patients also receive oral mycophenolate mofetil twice daily on days 0 to 27. Patients who undergo PBSCT from an unrelated donor receive oral cyclosporine twice daily on days -3 to 100 followed by a taper over 11 weeks in the absence of GVHD. These patients also receive oral mycophenolate mofetil three times daily on days 0 to 40 followed by a taper to day 96. After completion of study treatment, patients are followed up at 1, 3, 6, and 12 months, and then annually thereafter.