Treatment of Bone Marrow to Prevent Graft-Versus-Host Disease in Patients With Acute or Chronic Leukemia Undergoing Bone Marrow Transplantation

DISEASE CHARACTERISTICS: * Diagnosis of one of the following: * Acute myelogenous leukemia (AML) or acute lymphocytic leukemia (ALL) in first early relapse, second remission, or subsequent remission * AML in first complete remission with one of the following adverse features: * Antecedent hematologic disorder such as myelodysplasia * AML resulting from prior chemotherapy or radiotherapy * More than 1 course of induction chemotherapy to achieve remission or adverse cytogenetics such as Philadelphia chromosome 9:22, +8, +11; abnormal 12p; or deletions of chromosomes 5, 7, or 20 (3:3) * ALL in first complete remission with poor risk cytogenetics such as * Philadelphia chromosome 9:22, 8:14, or 4:11 OR * WBC greater than 100,000/mm3 OR * Time to achieve complete remission more than 4 weeks * Chronic myelogenous leukemia in chronic or accelerated phase * Myelodysplastic syndromes * Refractory anemia with excess blasts (RAEB) OR * RAEB in transformation * Unrelated bone marrow donor available * If matched at 6 of 6 HLA-A, -B, and -DR loci, patient must be 12 to 50 years * If matched at 5 of 6 loci, patient must be 12 to 35 years * No matched sibling donor available * No uncontrolled CNS leukemia PATIENT CHARACTERISTICS: Age: * See Disease Characteristics * 12 to 50 Performance status: * Karnofsky 70-100% Life expectancy: * At least 12 weeks Hematopoietic: * See Disease Characteristics Hepatic: * Bilirubin less than 2.5 times upper limit of normal (ULN) * SGOT or SGPT less than 2.5 times ULN Renal: * Creatinine no greater than 1.5 mg/dL Cardiovascular: * LVEF greater than 50% without medication Pulmonary: * DLCO and FVC at least 50% predicted Other: * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * No other serious medical illness * No uncontrolled diabetes mellitus * No uncontrolled and/or active infection * HIV negative PRIOR CONCURRENT THERAPY: Biologic therapy: * At least 3 weeks since prior immunotherapy and recovered * At least 1 year since prior autologous transplantation * No prior allogeneic transplantation Chemotherapy: * See Disease Characteristics * At least 3 weeks since prior chemotherapy (except hydroxyurea) and recovered Endocrine therapy: * At least 3 weeks since prior hormonal therapy and recovered Radiotherapy: * See Disease Characteristics * At least 3 weeks since prior radiotherapy and recovered * No prior radiotherapy at doses that would preclude study Surgery: * Not specified