HLA alloimmunization and blood requirements in orthotopic liver transplantation.

ORTHOTOPIC LIVER transplantation (OL T) is often accompanied by massive blood loss due to portal hypertension, difficult dissection as a result of previous abdominal surgery. and coagulation abnormalities. Major alterations of the coagulation factors such as prolonged prothrombin time (PT) and activated partial thromboplastin time (APTT). decreased fibrinogen levels and thrombocytopenia have already been documented in patients undergoing OLT. I•3 Moreover, problems like fibrinolysis and consumption coagulopathy have been demonstrated to play an important role in blood coagulation system alterations during such an operation;4.5 these factors often necessitate large quantities of blood products during OL T, despite recent adva nces. 2.6-8 Packed red blood cells (RBC), fresh frozen plasma (FFP), platelets (PL T) and cryoprecipitate (CRY) represent the different blood fractions commonly transfused during OL T. The relation between massive blood use in 0 L T, morbidity9 and mortalitylO.1I has already been described. We have investigated the role of HLA alloimmunization in intraoperative blood transfusion requirements during OL T. Alloimmunization can result from previous exposure to HLA antigens through transfusion, transplantation and pregnancy and is usually detected by serum screening for lymphocytotoxic antibodies. HLA plays a significant role in blood transfusions especially those involving platelets. It is well known that PL T express class I HLA antigens and specific alloimmunization to these antigens is a major cause of refractoriness in thrombocytopenic patients to platelet transfusions. 12·14 Our results demonstrate that HLA alloimmunization has a major effect on blood transfusion requirements during aLT. Intraoperative blood use was significantly increased in alloimmunized liver transplant recipients. This retrospective study indicates that pre-transplant screening of liver candidates is useful in estimating blood transfusion requirements duringOLT.