Editing Liver transplantation (section)

===Graft rejection===
After a liver transplantation, immune-mediated rejection (also known as '''rejection''') of the allograft may happen at any time. Rejection may present with lab findings: elevated AST, ALT, GGT; abnormal liver function values such as prothrombin time, ammonia level, bilirubin level, albumin concentration; and abnormal blood glucose. Physical findings may include encephalopathy, jaundice, bruising and bleeding tendency. Other nonspecific presentation may include malaise, anorexia, muscle ache, low fever, slight increase in white blood count and graft-site tenderness.{{citation needed|date=March 2022}}

Three types of graft rejection may occur: hyperacute rejection, acute rejection, and chronic rejection.
* '''Hyperacute rejection''' is caused by preformed anti-donor antibodies. It is characterized by the binding of these antibodies to antigens on vascular endothelial cells. [[Complement system|Complement activation]] is involved and the effect is usually profound. Hyperacute rejection happens within minutes to hours after the transplant procedure.
* '''Acute rejection''' is mediated by  [[T cell]]s (versus [[B cell|B-cell]]-mediated hyperacute rejection). It involves direct [[cytotoxicity]] and [[cytokine]] mediated pathways. Acute rejection is the most common and the primary target of immunosuppressive agents. Acute rejection is usually seen within days or weeks of the transplant.
* '''Chronic rejection''' is the presence of any sign and symptom of rejection after one year. The cause of chronic rejection is still unknown, but an acute rejection is a strong predictor of chronic rejections.