Reduced Intensity Total Body Irradiation + Thymoglobulin Followed by Allogeneic PBSCT

Inclusion Criteria:

Patients with hematological malignancies for which allogeneic stem cell transplantation indicated including non-Hodgkin lymphoma (NHL), multiple myeloma (MM), acute myeloid leukemia (AML), Hodgkin lymphoma (HD), chronic lymphocytic leukemia (CLL), chronic myelogenous leukemia (CML), and myelodysplastic syndrome (MDS)
Patients with HLA compatible related or unrelated stem cell donor, willing and able to serve as an allogenic HSC donor. Unrelated donors have to be matched at HLA-A, B, C and DRB1 loci. A single locus mismatch will be tolerated in the event a more closely matched donor is not available.
Patients age >/=40 to Patients between 18 and 40 years of age will be eligible only if they have co-morbidities precluding conventional allogeneic transplantation with full intensity myeloablative conditioning
Adequate cardiac, pulmonary, renal and hepatic function for transplant
Negative serology for HIV
Negative serum pregnancy test
Patients who have received therapeutic radiation to a localized field will be eligible, provided critical structure tolerance doses have not been exceeded
Patients who have had prior myeloablative autologous transplant will be eligible

Exclusion Criteria:

Evidence of uncontrolled viral, fungal, bacterial infection
Evidence of active meningeal or CNS disease
Prior therapy with rabbit ATG, prior treatment with equine ATG is allowed if more than 3 months ago
Breast feeding mothers are excluded