Case Report: A case of immune hemolytic anemia after liver transplantation: passenger lymphocyte syndrome is the culprit.

Passenger lymphocyte syndrome (PLS) is most commonly observed after solid organ transplantation with minor ABO blood group incompatibility. It consists of a set of clinical symptoms brought on by the remaining lymphocytes of the donor organ developing antibodies against the recipient's antigens. Here, we describe a typical case of PLS in a type A⁺ recipient receiving a liver transplant from a type O⁺ donor. She suffered from jaundice, abnormally decreased hemoglobin level, and severe hemolytic anemia without bleeding. During hemolysis, we detected a positive direct antiglobulin test (DAT), and the thermal elution test revealed the presence of IgG anti-A antibodies in her serum. When immunosuppressive agents and blood transfusion were used together, cross-matched O⁺ washing red blood cells led to an expected outcome without side effects.