Alemtuzumab, Busulfan, and Cyclophosphamide Followed By a Donor Stem Cell Transplant in Treating Patients With Hematologic Cancer

DISEASE CHARACTERISTICS:

* Confirmed diagnosis of one of the following:

  * Primary acute myeloid leukemia (AML) meeting any of the following criteria:

    * First complete remission (CR; defined as \< 5% blasts in marrow) with high-risk features as defined by failure to achieve remission by day 21 after induction chemotherapy, or the presence of chromosomal abnormalities involving any of the following:

      * -5/del(5q)
      * -7/del(7q)
      * Inversion 3q
      * Abnormalities of 11q23, 20q, 21q, del(9q),
      * Translocation 6;9
      * Translocation 9;22
      * Abnormalities of 17p
      * Complex karyotype with ≥ 3 abnormalities
    * Second CR or subsequent in remission
    * Refractory or relapsed disease
  * Secondary AML in remission or relapse
  * Chronic myelogenous leukemia (CML) in accelerated or blast phase meeting the following criteria:

    * Accelerated phase is defined by any one of the following:

      * Blasts 10% to 19% of peripheral blood white cells or bone marrow cells
      * Peripheral blood basophils ≥ 20%
      * Persistent thrombocytopenia (\< 100,000/mm³) unrelated to therapy, or persistent thrombocytosis (\> 1,000,000/mm³) unresponsive to therapy
      * Increasing spleen size and increasing WBC count unresponsive to therapy
      * Cytogenetic evidence of clonal evolution (i.e., the appearance of an additional genetic abnormality that was not present in the initial specimen at the time of diagnosis of chronic phase CML)
    * Blast phase is defined by any of the following:

      * Blasts ≥ 20% of peripheral blood white cells or bone marrow cells
      * Extramedullary blast proliferation
      * Large foci or clusters of blasts in bone marrow biopsy
  * Primary myelodysplastic syndromes (MDS) with an IPSS score \> 1.5
  * Secondary MDS with any IPSS score
  * Primary acute lymphoblastic leukemia meeting any of the following criteria:

    * First CR (\< 5% blasts in marrow) with high-risk features as defined by 1 of the following:

      * Failure to achieve remission after first induction chemotherapy
      * Presence of chromosomal abnormalities including hypodiploidy or abnormalities of 11q23 or translocation 9;22
    * Second CR or subsequent in remission
    * Refractory or relapsed disease
* No patients for whom a suitable HLA genotypically identical sibling or fully matched HLA-A, -B, -C, and -DRB1 unrelated donor is available
* No active CNS involvement with disease
* Donors must meet the following criteria:

  * Unrelated volunteer donors who are mismatched for more than one HLA-class I alleles or antigens or for one HLA-class I antigen, but matched by high-resolution typing at HLA-DRB1 and -DQB1, OR who are mismatched for one or more HLA-class II alleles or antigens, but matched by high-resolution typing at HLA-A, -B, and -C

    * No two-antigen mismatch at a single HLA-A, -B, or -C locus
    * No mismatching of class I and class II HLA
    * Matching must be based on results of high-resolution typing at HLA-A, -B, -C, - DRB1, and -DQB1

PATIENT CHARACTERISTICS:

* Karnofsky performance status 50-100%
* No symptomatic coronary artery disease or symptomatic congestive heart failure
* No hepatic disease with transaminases or bilirubin \> 2 times upper limit of normal except for isolated hyperbilirubinemia attributed to Gilbert's syndrome
* No severe hypoxemia with room air P\_AO\_2 \< 70, supplemental oxygen-dependence, or DLCO \< 60% predicted
* No impaired renal function with creatinine \> 2 times upper limit of normal or creatinine clearance \< 50% normal
* Not HIV seropositive
* Not pregnant or breast-feeding
* Fertile patients must use effective contraception
* No active infections that are untreated or failing to respond to appropriate therapy

PRIOR CONCURRENT THERAPY:

Inclusion criteria:

* See Disease Characteristics

Exclusion criteria:

* Prior allogeneic or autologous bone marrow, peripheral blood stem cell, or umbilical cord blood transplantation using a high-dose total-body irradiation regimen