346: Homeostatic and Inflammatory Processes Contribute to Elevated Plasma Levels of B Cell Activating Factor (BAFF) in Chronic Graft Versus Host Disease (CGVHD)

Abstract

BAFF, a non-redundant cytokine produced by myeloid cells, plays a critical role in the normal homeostatic maintenance, activation and function of B cells. Elevated circulating levels of BAFF, however, have been observed in systemic autoimmune disorders and, in murine models, have been linked to a failure to delete auto-reactive B cells. We similarly observed elevated plasma BAFF levels in 77 patients in an ongoing NCI CGVHD natural history protocol, with a median of 2845 pg/ml (range 92 to 17058), as compared to 556 pg/ml (range 75 to 1834) in 18 normal donors.