Nonmyeloablative conditioning generates autoantigen-encoding bone marrow that prevents and cures an experimental...

Autoimmune diseases result from chronic targeted immune responses that lead to tissue pathology and disease. The potential of autologous hematopoietic stem cells transplantation as a treatment for autoimmunity is currently being trialled but disease relapse is an issue. We have previously shown in a mouse model of experimental autoimmune encephalomyelitis (EAE) that the transplantation of bone marrow (BM) transduced to encode the autoantigen myelin oligodendrocyte glycoprotein (MOG) can prevent disease induction. However these studies were performed using lethal irradiation to generate BM chimeras and a critical factor for translation to humans would be the ability to utilize low toxic preconditioning regimes. In this study, treosulfan was used as a nonmyeloablative agent to generate BM chimeras encoding MOG and assessed in models of EAE induction and reversal. We find that treosulfan conditioning can promote a low degree of chimerism that is sufficient to promote antigen specific tolerance and protect mice from EAE. When incorporated into a curative protocol for treating mice with established EAE, nonmyeloablative conditioning and low chimerism was equally efficient in maintaining disease resistance. These studies further underpin the potential and feasibility of utilizing a gene therapy approach to treat autoimmune disease.