Peripheral Stem Cell Transplant in Treating Patients With High-Risk Leukemia

DISEASE CHARACTERISTICS: * Diagnosis of 1 of the following: * High-risk myelodysplastic syndromes (MDS), meeting 1 of the following criteria: * Transformation to acute leukemia defined by at least 15% blasts * Secondary to prior treatment with chemotherapy and/or radiotherapy * Presence of complex cytogenetics (at least 3 karyotypic abnormalities) * Monosomy or deletion of chromosome 7 * Acute myeloid leukemia (AML), meeting 1 of the following criteria : * High-risk AML in first remission and meeting 1 of the following criteria: * At least 3 karyotypic abnormalities * Monosomy or deletion of chromosome 5 or 7 = 11q23 chromosomal abnormality * Prior diagnosis of MDS * Received prior radiotherapy or chemotherapy * In second or subsequent remission * Primary induction failure or partial remission * Untested or sensitive relapse * Chronic myelogenous leukemia, meeting 1 of the following criteria: * Blast crisis * Accelerated phase disease that has failed prior treatment with imatinib mesylate, defined as a failure to achieve hematologic response after 3 months of standard dose (600 mg/day) therapy or disease progression on therapy * Myeloproliferative disease * The following diagnoses are eligible: * Agnogenic myeloid metaplasia * Essential thrombocythemia * Polycythemia vera * Must have evidence of transformation to acute leukemia * Acute lymphocytic leukemia (ALL), meeting 1 of the following criteria: * High-risk ALL in first remission defined by 1 of the following: * t(9;22) or 11q23 chromosomal abnormality * Complete response at least 4 weeks after induction therapy OR requiring at least 2 induction regimens * Second or subsequent remission * No relapsed leukemia refractory to appropriate salvage therapy * Availability of an HLA-mismatched family donor * Donor age 75 or under * No better donor alternative (i.e., HLA-matched related or unrelated stem cell donor) is available PATIENT CHARACTERISTICS: Age * 10 to 50 Performance status * ECOG 0-1 Life expectancy * More than 3 months Hematopoietic * See Disease Characteristics Hepatic * Bilirubin no greater than 4 mg/dL * Transaminases no greater than 3 times upper limit of normal Renal * Creatinine no greater than 2.0 mg/dL OR * Creatinine clearance at least 60 mL/min Cardiovascular * LVEF at least 40% Pulmonary * DLCO at least 65% of predicted Other * Not pregnant * Negative pregnancy test * HIV negative * No other prior malignancy except basal cell or squamous cell skin cancer or a remote history of cancer now considered cured * No major organ dysfunction that would preclude transplantation * No major anticipated illness or organ failure that would preclude transplantation * No severe psychiatric illness or mental deficiency that would preclude giving informed consent or complying with study * No uncontrolled infection PRIOR CONCURRENT THERAPY: Biologic therapy * Not specified Chemotherapy * See Disease Characteristics Endocrine therapy * Not specified Radiotherapy * See Disease Characteristics Surgery * Not specified