A Study to Evaluate the Effect of ATG-F on Engraftment, Graft Versus Host Disease (GVHD) and Graft Versus Leukemia (GVL) Effect in Haplo-identical SCT

Inclusion Criteria: 1. Patient age 3-70 years old with a disease necessitating allogeneic SCT. 2. Patients must have a mismatched donor willing and capable of donating peripheral blood stem cells and/or bone marrow progenitor cells using conventional techniques, and lymphocytes if indicated (mismatched defined as 3/6-4/6 HLA matching). 3. Each patient / patient's guardian must sign written informed consent. 4. Patients must have an ECOG PS ≤ 2; Creatinine \<2.0 mg/dl; Ejection fraction \>40%; DLCO \>50% of predicted; Serum bilirubin \<3 gm/dl; elevated GPT or GOT \>3 x normal values. Exclusion Criteria: 1. Not fulfilling any of the inclusion criteria. 2. Active life-threatening infection. 3. Overt untreated infection. 4. Known hypersensitivity to ATG. 5. HIV seropositivity, Hepatitis B or C antigen positivity with evidence of active hepatitis. 6. Pregnant or lactating women. 7. Donor contraindication (HIV seropositive confirmed by Western Blot Hepatitis B antigenemia; positive HCV antibodies with positive HCV PCR; evidence of bone marrow disease; unable to donate bone marrow or peripheral blood due to concurrent medical condition). 8. Inability to comply with study requirements.