Allogeneic Stem Cell Transplantation for the Treatment of Multiple Sclerosis

While the cause of MS in not known, there is an autoimmune component that destroys nerve cells. Autoimmunity is a condition where an individual's immune system attacks his/her own cells. Bone marrow stem cell transplantation has been shown to halt autoimmunity. Stem cell transplant can be performed using the patient's own cells, or donor cells. The general consensus in the field is that donor transplant is most likely to halt disease progression. This study is designed to evaluate the safety of a donor transplant procedure as a therapy for relapsing remitting multiple sclerosis (RRMS). Two factors limit the widespread application of traditional donor stem cell transplant: 1) preparing the patient for transplant (conditioning); and 2) graft-versus-host disease (GVHD). Traditional conditioning destroys the recipient's immune system and requires that the marrow transplant be successful because the patient is unable to fight off infection if the donor cells do not survive. GVHD occurs when donor immune cells recognize the recipient's cells as foreign tissue and attack them. Severe GVHD can result in death. This study utilizes a new approach to conditioning which leaves the patient's immune system intact. The transplant product is depleted of GVHD-producing cells but retains tolerance-promoting cells, called facilitating cells, which are intended to ensure the donor and recipient cells coexists peacefully. The toxicity of conditioning and transplantation is significantly reduced. The end result is a marrow system that contains recipient and donor cells, a state called mixed chimerism. In this study, we will determine the appropriate cell dose to safely establish mixed chimerism following partial conditioning in patients with RRMS. The study takes a gradual approach to increasing the cell dose to achieve mixed chimerism. Each patient will receive a cell dose one unit above the dose received by the most recent safely transplanted patient. We believe this study will provide a breakthrough in the treatment of MS. The goal of this study is to evaluate the potential of safely establishing mixed chimerism to interrupt the autoimmune process and end the devastating effects of MS.