Inclusion Criteria:

1. Patient age 14-75 years old with a disease necessitating allogeneic SCT.

2. In order to increase security, only full matched donors will be allowed and must be
willing and capable of donating peripheral blood stem cells preferably, or bone
marrow progenitor cells using conventional techniques, and lymphocytes if indicated.

3. Patients must sign written informed consents.

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. Hypersensitivity to alefacept.

5. HIV seropositivity, Hepatitis B or C antigen positivity with active hepatitis.

6. Pregnant or lactating women.

7. Donor contraindication (HIV seropositive confirmed by western blot).

8. Hepatitis B antigenemia.

9. Evidence of bone marrow disease.

10. Unable to donate bone marrow or peripheral blood due to concurrent medical condition.

11. Inability to comply with study requirements.