The purpose of the study is to:

• Establish and evaluate a system for collection of filgrastim-mobilized peripheral blood stem cells from National Marrow Donor Program donors (NMDP) donors
• Assess the safety among NMDP donors of filgrastim administration and PBSC leukapheresis
• Assess the safety and efficacy of filgrastim-mobilized PBSC in unrelated donor hematopoietic stem cell transplant recipients
• Determine the acceptability of stem cell donation by filgrastim stimulated apheresis in normal donors

For many years, allogeneic bone marrow transplantation has been used to successfully treat leukemias, other hematologic conditions and congenital disorders. The first unrelated donor transplants were performed in the late 1970s, but this procedure did not become widely available until the development of several consolidated unrelated donor registries around the world. The National Marrow Donor Program, established in 1987, is the world's largest registry and currently lists more than 7 million donors. Since its beginning, NMDP has facilitated more than 30,000 unrelated transplants.

Although not a licensed indication, considerable experience has been accumulated concerning administration of filgrastim to normal adults. Most of these adults were volunteer research subjects or donors of PBSC for use in related donor transplants. Beginning in February 1997, filgrastim stimulated PBSC have been collected from NMDP donors under protocol. The protocol (locally referred to as G2) began under an NMDP-sponsored Investigational New Drug (IND) application filed with FDA for collecting PBSC for a second donation following an initial donation of bone marrow. In 1999 a second protocol was opened (locally referred to as G1) as requests for PBSC as a primary donation source became more common. In 2005 the two protocols were combined to eliminate redundancy and provide for ease of use.

The protocol establishes and evaluates a system to supply peripheral blood stem cell (PBSC) products for use in unrelated donor hematopoietic stem cell (HSC) transplantation. The protocol describes processes for donor identification, education and evaluation. Procedures for administration and monitoring of the stem cell mobilizing agent filgrastim are included. The protocol also describes procedures for the collection of PBSC products by leukapheresis and includes provisions for long term donor follow-up.

Inclusion Criteria:

1. PBSC donors must meet the same criteria as NMDP marrow donors. These criteria are set forth in the Donor Center Manual of Operations.
2. Confirmatory pregnancy test must be performed within 15 days of collection and prior to the start of filgrastim administration; this may require more than one test to be performed.

Exclusion Criteria:

1. Pregnancy or uninterruptible breastfeeding. Pregnancy is an absolute contraindication under this protocol. Women who are breastfeeding must be willing and able to interrupt breastfeeding during the administration of filgrastim and for two days following the final dose.
2. Sensitivity to filgrastim or to E. coli-derived recombinant protein products.
3. History of autoimmune disorders, including rheumatic diseases and thyroid disorders. Exception: As with bone marrow donations, donors with a history of thyroid disease who have undergone successful therapy may be suitable.
4. History of deep vein thrombosis or pulmonary embolism.
5. History of iritis or episcleritis.
6. Thrombocytopenia < 150 x 10^9/L (< 150,000/uL) at baseline evaluation.
7. Current treatment with lithium. Drug interactions between filgrastim and lithium, which may potentiate the release of neutrophils, have not been fully evaluated.
8. Positive Hemoglobin-Solubility (e.g., SickleDex or equivalent) test.
9. Donors receiving experimental therapy or investigational agents.
10. Positive pregnancy test collected/reported prior to start of filgrastim.