Total Marrow and Lymphoid Irradiation and Chemotherapy for High-Risk Acute Leukemia

RATIONALE: Giving chemotherapy and total marrow and lymphoid irradiation before allogeneic hematopoietic cell transplant helps stop the growth of leukemia cells. It may also stop the patient's immune system from rejecting the donor's stem cells. When the healthy stem cells from a donor are infused into the patient they may achieve brand new hematopoietic recovery. Sometimes the transplanted cells from a donor can make an immune response against the body's normal cells, resulting in graft versus-host disease. PURPOSE: This study is to evaluate the toxicity and efficacy of total marrow and lymphoid irradiation conditioning when given together with combination chemotherapy and allogeneic peripheral blood stem cell transplant in treating patients with high-risk acute leukemia.