Donor Stem Cell Transplant in Treating Patients With Hematologic Cancer or Other Diseases

OBJECTIVES: Primary * Determine the feasibility (i.e., risk of treatment-related mortality during the first 6 months after transplantation) of administering reduced-intensity allogeneic hematopoietic stem cell transplantation to patients with hematologic cancer or other diseases. Secondary * Determine the response rate (partial and complete response), 6- and 12-month probabilities of response, and time to progression in patients treated with this regimen. * Determine the risk of acute and chronic graft-versus-host disease in patients treated with this regimen. * Determine other toxicities of this regimen in these patients. * Determine the overall survival and disease-free survival of patients treated with this regimen. * Determine the impact of iron status on overall and disease-free survival. * Determine the influence of quality of life (at time of transplantation) on overall survival. OUTLINE: * Preparative regimen: Patients receive fludarabine phosphate IV over 30 minutes on days -7 to -3. Patients also receive busulfan IV over 2 hours every 6 hours on days -4 and -3 or melphalan IV over 2 hours on day -3. * Graft-versus-host disease (GVHD) prophylaxis: Patients with matched related donors receive oral tacrolimus twice daily on days -1 to 90 followed by a taper until day 180. Patients also receive methotrexate IV on days 1, 3, and 6. Patients with matched unrelated and 9/10 matched related donors receive oral tacrolimus twice daily on days -1 to 180 followed by a taper; methotrexate IV on days 1, 3, 6, and 11; and oral mycophenolate mofetil twice daily on days -2 to 60 followed by a taper. All patients also receive antithymocyte globulin IV over 4 to 6 hours once a day on days -4 to -1. * Allogeneic stem cell transplantation: Patients undergo allogeneic peripheral blood stem cell transplantation or bone marrow transplantation on day 0. Patients receive filgrastim (G-CSF) beginning on day 7 and continuing until blood counts recover. * Lymphocyte infusion: Patients with progressive or stable disease while off immunosuppression and no active GVHD may receive up to 3 donor lymphocyte infusions from the original donor at 8-week intervals beginning on day 180 or 210 . Quality of life is assessed at baseline. After completion of study therapy, patients are followed every 3 months for 2 years and then every 6 months for up to 3 years. PROJECTED ACCRUAL: A total of 40 patients will be accrued for this study.