Participants have a central venous line (plastic tube) inserted into a neck or chest vein for administering stem cells and medicines and for drawing blood. They undergo seven apheresis procedures during the course of the study to collect stem cells for transplant and for research. For apheresis, whole blood is collected through a needle in an arm vein and directed to a cell-separating machine where the white cells are extracted and the rest of the blood is returned to the patient through the same needle.