Some drugs, such as hematopoietic cytokines, result in mobilization of primitive stem cells out of the bone marrow space and into the blood, but the mechanisms of this process are still poorly understood. A better understanding of this process could greatly improve clinical results in transplantation, cancer treatment, and potentially genetic therapy of a wide variety of disorders. In this protocol, we will study two different mobilization treatments and compare how efficient they are at increasing the number of primitive cells in the blood in patients with multiple myeloma. These cells will be collected by apheresis, and used for autologous transplantation following high dose chemotherapy. This aggressive approach to treatment in multiple myeloma has been shown to improve remission rates and survival without active disease. The use of a larger number of blood stem cells may decrease the toxicity associated with the procedure. In the research laboratory, we will study a number of characteristics of the primitive cells in the blood and the bone marrow after treatment with the mobilizing drugs. These studies will help us to design future transplantation and genetic therapy protocols.