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.