Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosis of 1 of the following:

- Acute lymphocytic leukemia (ALL) or acute myeloid leukemia (AML) in first or
subsequent remission

- ALL or AML in relapse or primary refractory ALL or AML with a circulating blast
count ≤ 10,000/mm^3

- Refractory anemia with excess blasts (RAEB) (RAEB-1 or RAEB-2) if the patient
has received induction chemotherapy within the past 60 days

- Appropriate candidate for allogeneic hematopoietic stem cell transplantation (HSCT)

- No CNS involvement refractory to intrathecal chemotherapy and/or standard
cranial-spinal radiotherapy

PATIENT CHARACTERISTICS:

- Age 14-55

- Creatinine < 1.5 mg/dL

- Cardiac ejection fraction > 45%

- DLCO corrected > 60% of predicted

- Total bilirubin < 2 times upper limit of normal (ULN) (unless attributed to Gilbert
syndrome)

- AST and ALT < 2 times ULN

- Not pregnant or nursing

- Fertile patients must use effective contraception during and for 12 months after
transplantation

- HIV negative

- No co-existing disease (other than leukemia or RAEB) that would limit life expectancy
to < 3 months

- No uncontrolled infection that, in the opinion of the consulting infectious disease
physician, would contraindicate myeloablative HSCT

- No other medical condition that would contraindicate HSCT

- No known hypersensitivity to tacrolimus

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- No prior HSCT

- No concurrent participation in other experimental studies for the prevention of
graft-vs-host disease

DONOR CHARACTERISTICS:

- Genotypic or phenotypic HLA-identical related donor

- Able to donate peripheral blood stem cells

- Age > 14 years

- Applicable to male patients only: No female donors who have previously given birth to
a male child or have had a pregnancy beyond the first trimester miscarriage or
termination of pregnancy or nursing

- No donors who have received blood transfusions

- No CD45 Mutation with aberrant CD45RA isoform expression