The apheresis procedure includes collecting blood through a large catheter placed under the collarbone or in the arm with the assistance of a device known as a cell separator. This device separates the stem cells from the rest of the blood and returns the rest of the blood to the participant. The procedure is usually done as an outpatient and takes between 4-5 hours to perform. Most patients collect enough cells for a transplant after 1 or 2 procedures. In this study, a maximum of 5 procedures are allowed.