354: Elevated Levels of CD19+ CD21- Transitional B cells in Chronic Graft Versus Host Disease (CGVHD) Associated with Elevated Plasma BAFF Levels and BAFF Receptor Expression

Abstract

B Cell Activating Factor (BAFF also termed BLyS) is a critical factor in the survival, differentiation and function of B cells, but elevated plasma levels of BAFF have been associated with the development of B-cell mediated autoimmunity, both in murine models and in human disease. In mice BAFF administration-induced autoimmunity has been linked to increased survival of the transitional B cell population, resulting in a failure to eliminate auto-reactive B cell populations by negative selection during B cell maturation.