Published online Sep 28, 2013. doi: 10.3748/wjg.v19.i36.5981
Revised: June 5, 2013
Accepted: July 18, 2013
Published online: September 28, 2013
The liver has particular tolerogenic properties that allow its spontaneous acceptance in some animal species. Liver structure is considered to favor a tolerogenic environment. The peripheral tolerance mechanisms also play a role in spontaneous tolerance to liver graft. In a clinical setting, the main challenge nowadays facing liver transplantation is minimization of immunosuppression with the goal of donor-specific tolerance. Mechanisms involved in tolerance to transplanted organs are complex and partly unknown. A significant mechanism in tolerance induction is chimerism. Chimerism can be induced through transplantation of allogeneic donor bone marrow/stem cells under appropriate host conditioning. This review focuses on the tolerance mechanisms in liver transplantation and highlights the role of chimerism and allogeneic bone marrow/stem cell transplantation in tolerance development.
Core tip: The liver is considered an immune privileged organ. The main challenge facing liver transplantation is to induce donor-specific tolerance. Numerous reports have documented the phenomenon of microchimerism in liver transplant recipients. Most have demonstrated that higher levels of chimerism in liver transplantation are associated with reduced incidence of acute rejection and better initial graft acceptance. Mechanisms involved in chimerism-induced tolerance have only been partly elucidated. Chimerism can be induced through transplantation of allogeneic donor bone marrow cells under appropriate host conditioning and represents a clinically feasible approach for the induction of durable liver transplantation tolerance.