Inclusion Criteria

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