Transplantation of ABO-unmatched solid organs has been associated with the development of immune hemolysis due to donor-derived antibodies produced by passenger lymphocytes in the graft, called "Passenger Lymphocyte Syndrome". In a liver transplantation, about 40% of patients at risk has detectable donor-derived antibodies and hemolytic anemia occurs in 29% of patients. It is characterized by hemoglobinemia, a rapid fall in hemoglobin, hyperbilirubinemia, and an excessive red cell transfusion requirement occurring 1 to 3 weeks after the transplantation. These clinical findings are accompanied by the laboratory findings of a positive direct antiglobulin test and the detection of unexpected antibodies in the patients' red cell eluate and serum. Both the hemolytic anemia and serology resolve over the course of weeks to months. To the best of our knowledge, this is the first case of hemolytic anemia due to passenger lymphocyte syndrome after ABO-unmatched liver transplantation in Korea. (Korean J Hepatol 1999;5:162－167)
