Collection of Peripheral Blood Stem Cells Using G-CSF and Plerixafor in Normal Volunteers

Overview

Background: * Many treatments for immune system disorders involve the use of stem cells that have been collected from blood marrow. To obtain these stem cells without surgery, individuals receive granulocyte colony-stimulating factor (G-CSF) to encourage the production of stem cells that can be collected through blood donations. However, not all patients or normal donors respond to G-CSF alone. * Plerixafor, recently approved by the Food and Drug Administration, is different from G-CSF but also allows stem cells to be collected from donated blood. However, more research is needed on the quality and viability of the stem cells collected after using both G-CSF and plerixafor. Objectives: \- To collect and study the blood cells produced after treatment with G-CSF and plerixafor in healthy volunteers. Eligibility: \- Healthy volunteers between 18 and 65 years of age who are eligible to donate blood. Design: * Participants will be screened with a medical history, physical examination, and initial blood tests. * At the start of the study cycle, participants will receive daily morning injections of G-CSF for 5 days. These may be given at the clinical center or by the participant after teaching, depending on the participant s preference. * On the morning of Day 4, participants will visit the clinical center to provide a blood sample after the injection. On the evening of Day 4, participants will receive an injection of plerixafor. * Participants will have the final injection of G-CSF on the morning of Day 5, and will provide another blood sample. * On Day 5, participants will have apheresis to separate the stem cells from the rest of the blood. The apheresis may take up to 5 hours to complete. * The study will end after a follow-up phone call 7 to 14 days after the apheresis procedure.

Hematopoietic stem cells that have been mobilized from the bone marrow into the peripheral circulation are readily collected by apheresis, and may be used for several purposes. They are used for allogeneic and autologous transplantation and are often manipulated in various ways depending on the goal of the transplant. Gene therapy for immunodeficiencies relies on the collection of these cells. Traditionally, mobilization has been done using granulocyte colony stimulating factor (G-CSF). However not all patients or normal donors respond to GCSF alone. Plerixafor, a recently Food and Drug Administration (FDA) approved drug, has a unique mode of action distinct from that of GCSF, but also results in mobilization of peripheral blood progenitors into the circulation, allowing their collection by standard apheresis. The quality of these cells for transduction using viral vectors in anticipation of gene therapy uses has not been thoroughly assessed, and there are theoretical considerations why vectors that use various envelopes for cell binding may be affected by the use of this CXCR4 antagonist. In order to be able to assess the transduction and engraftment of these cells in murine models, we will perform collection and mobilization on 5 healthy volunteers at the NIH Clinical Center using the FDA approved medications G-CSF and plerixafor.