Inclusion Criteria:

- Patients with hematologic malignancies and non-malignancies who are candidates for
matched sibling donor allogeneic bone marrow transplantation are eligible for this
study.

- Patients who are under 55 years of age.

- Patients who have a life expectancy of at least 12 weeks and a performance status of
at least 2 Zubrod or 70% Karnofsky status prior to transplantation.

- Patients who are acceptable candidates for marrow transplantation based on their
pre-BMT evaluation.

- Patients who have available histocompatible siblings who have been medically approved
as marrow donors.

- Patients who sign informed consent for the protocol approved by the Institutional
Review Board of Emory University/Children's Healthcare of Atlanta.

- Donors must be 5 years of age or older, and have completed routine donor evaluations
and signed (by parent or legal guardian) informed consent for the protocol approved
by the Institutional Review Board of Emory University/Children's Healthcare of
Atlanta.

Exclusion Criteria:

- Patients will not be excluded based on sex, racial, or ethnic background.

- Patients will be excluded if they demonstrate significant functional deficits in
major organs, which would obviously interfere with a successful outcome following
bone marrow transplant utilizing the following guidelines:

- Evidence of active, deep seated, life-threatening infections for which there is
no known effective therapy (e.g. certain fungal species, HIV, etc.).

- Patients with hemoglobinopathy (e.g. sickle cell disease and thalassemia) will
not be eligible for this protocol. However, filgrastim mobilization, large
volume apheresis, processing, and cryopreservation appears to be safe in donors
with sickle cell trait.

- Patients have had greater than two leukemic episodes, active central nervous
system (CNS) and/or leukemic disease and blast crisis in chronic myelogenous
leukemia (CML) patients.

- Patients will be excluded if they are women of childbearing potential who are
currently pregnant (beta-hCG+) or who are not practicing adequate contraception.

- Patients who have had previous stem cell transplant will be excluded.

- Donors will be excluded if they are sensitive to E. coli-derived protein.