People interested in participating in this study will have a complete history and general medical examinations before beginning the study. Following the screening, you will have a procedure called leukapheresis, in which white blood cells are removed, but your own red blood cells are returned. The procedure takes approximately 3 hours and is similar to blood donation. The leukapheresis is done during a same day admission to the hospital by an outside blood collection company with trained nurses and certified equipment.