Dr. Xian Li's research is focused on the fundamental mechanisms of transplant rejection and transplant tolerance; key areas of his interests include T cell fate decisions, costimulatory molecules, and innate immune recognition, and how such events and pathways affect transplant outcomes. The overall goal of his team is to develop better therapies for transplant patients, with specific emphasis on creation of transplant tolerance, so that transpant patients could enjoy long-term graft survival without life long immunosuppression.

Transplantation of genetically disparate grafts always triggers the activation of both destructive and protective immune responses and it is the balance of those opposing responses that eventually determines whether a graft is rejected or accepted. The current focus in the lab is to understand how costimulatory molecules and cytokines regulate the fate and the functional attributes of T cells after transplantation. As these molecules and pathways control survival as well as effector differentiation of activated T cells, the promise is that by selectively manipulating these pathways, the graft-destructive T cells can be pushed to apoptotic cell death to clear them from allograft recipients, and at the same time, supporting the outgrowth of graft protective T cells. These strategies may hold great promise in establishment of immune tolerance, so life-long immunosuppression could be avoided. Dr. Li's long-term goal is to understand how transplant tolerance could be reliably induced and maintained, and whether transplant tolerance could be measurable and predictable in transplant patients.