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