Liver Rejection

Rejection can be broadly defined as an immunologic reaction to the presence of a foreign tissue or organ that has the potential to result in graft dysfunction and failure. Viewed from a biological perspective, any recipient’s immune system will likely be altered after transplantation, resulting in immune activation. However, viewed from a clinical perspective, because of baseline immunosuppressive therapy, only some recipients manifest clinical symptoms of allograft recognition with - in the case of liver transplantation - liver biochemical abnormalities or frank hepatic dysfunction. Therefore, it is important to distinguish between “biological” and “clinically relevant” rejection, that may require additional immunosuppressive treatment.
Immunopathologically, rejection can be classified on the basis of the effector mechanisms responsible for tissue damage, such as:
·	Humoral rejection 
·	Acute rejection 
·	Chronic rejection