Bone Marrow Transplantation in Treating Patients With Leukemia, Myelodysplasia, or Lymphoblastic Lymphoma

RATIONALE: Bone marrow transplantation may be able to replace immune cells that were destroyed by chemotherapy or radiation therapy used to kill cancer cells. Sometimes the transplanted cells from a donor can make an immune response against the body's normal cells. Eliminating the T cells from the donor cells before transplanting them may prevent this from happening. PURPOSE: Randomized phase II/III trial to compare the effectiveness of conventional bone marrow transplantation with T cell-depleted bone marrow transplantation in treating patients who have leukemia, myelodysplasia, or lymphoblastic lymphoma.