Reduced-Intensity Busulfan and Fludarabine With or Without Antithymocyte Globulin Followed by Donor Stem Cell Transplant in Treating Patients With Hematologic Cancer or Other Disease

DISEASE CHARACTERISTICS:

Histologically confirmed diagnosis of 1 of the following:

Chronic lymphocytic leukemia (CLL), meeting the following criteria:

Absolute lymphocyte count > 5,000/mm³
Lymphocytes must appear morphologically mature with < 55% prolymphocytes
Lymphocyte phenotype with expression of CD19 and cluster of differentiation 5 (CD5)

Prolymphocytic leukemia (PLL), meeting the following criteria:

Absolute lymphocyte count > 5,000/mm³
More than 55% prolymphocytes
Morphologically diagnosed

Chronic myelogenous leukemia (CML), meeting the following criteria:

Diagnosis of CML or similar myeloproliferative disorders based on t(9;22) or related t(9;12) cytogenetic abnormalities AND characterized by elevated white blood cell (WBC) counts in peripheral blood or bone marrow
In first chronic phase CML and a candidate for treatment with reduced-dose busulfan
Patients with other cytogenetic abnormalities, such as t(9;12), that are associated with an aggressive clinical course are eligible

Non-Hodgkin's lymphoma (NHL), meeting the following criteria:

Any World Health Organization (WHO) class histologic subtype allowed
Core biopsies are acceptable provided they contain adequate tissue for primary diagnosis and immunophenotyping
Bone marrow biopsies as sole means of diagnosis are not allowed for follicular lymphoma

Hodgkin's lymphoma, meeting the following criteria:

Any WHO class histologic subtype allowed
Core biopsies are acceptable provided they contain adequate tissue for primary diagnosis and immunophenotyping

Multiple myeloma, meeting the following criteria:

Active disease requiring treatment (Durie-Salmon stages I, II, or III)
Acute myeloid leukemia with documented control, defined as < 10% bone marrow blasts and no circulating blasts

Acute lymphoblastic leukemia, meeting the following criteria:

In early first relapse or beyond OR in first complete remission and has 1 of the following high-risk features:

t(9;22) or t(4;11)
WBC count > 30,000/mm³ at presentation
Non-T-cell phenotype
More than 30 years of age

Agnogenic myeloid metaplasia/myelofibrosis

Patients who are transfusion dependent or who have evolving myelodysplastic or leukemic features or high-risk cytogenetic abnormalities are eligible
Myelodysplastic syndromes (MDS) as defined by WHO criteria

Meets 1 of the following criteria:

Over 55 years of age
Ineligible for busulfan-based therapy based on diminished organ function or poor performance status
Indolent and chemotherapy-responsive CLL, low-grade NHL, small lymphocytic lymphoma, or PLL
Patients who have undergone prior autologous stem cell transplantation are preferentially enrolled on clinical trial CALGB-100002, if available and patient is eligible

HLA-matched or mismatched related donor or HLA-matched unrelated donor available

HLA-identical sibling (6/6 or 9/10) (minimal serologic typing required for class I [A, B]; molecular typing required for class II (DRB1))
9/10 matched unrelated donor (MUD) (molecular analysis at HLA A, B, C, DRB1, and DQB1 by high resolution typing required)
5/6 MUD (molecular analysis at HLA A, B, and DRB1 required)
No syngeneic donors

PATIENT CHARACTERISTICS:

Creatinine clearance ≥ 40 mL/min
Bilirubin ≤ 3 times upper limit of normal (ULN)
aspartate aminotransferase (AST) ≤ 3 times ULN
Diffusing capacity of the lungs for carbon monoxide (DLCO) > 40% with no symptomatic pulmonary disease
Left ventricular ejection fraction (LVEF) ≥ 30% by multigated acquisition scan (MUGA)
No uncontrolled diabetes mellitus or active serious infection
No known hypersensitivity to Escherichia coli-derived products
No HIV infection
Not pregnant or nursing
Negative pregnancy test
Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

See Disease Characteristics
More than 4 weeks since prior chemotherapy, radiotherapy (except prophylactic cranial x-ray therapy), or surgery