Passenger Lymphocyte Syndrome Triggered Hemolytic Anemia Following Orthotopic Liver Transplantation: A Case Report

Passenger lymphocyte syndrome (PLS) is a rare but recognized cause of immune-mediated hemolytic anemia in solid organ transplant recipients, most often occurring in the setting of minor ABO incompatibility but also described with non-ABO red cell antibodies. We present the case of a 48-year-old male with alcohol-related cirrhosis who developed PLS following orthotopic liver transplantation. His postoperative hospital course was complicated by acute kidney injury, delirium, and severe anemia requiring intensive care unit readmission. Diagnostic workup demonstrated hemolysis with an acute hemoglobin drop, elevated lactate dehydrogenase, indirect hyperbilirubinemia, undetectable haptoglobin, a positive direct antiglobulin test, and anti-B antibodies in the recipient serum. Management included donor-type packed red blood cell transfusions, supportive care, close hemolysis monitoring, and adjustment of immunosuppressive therapy. This case underscores the importance of early recognition of PLS in postliver transplant patients with an acute hemoglobin decline and highlights the need for multidisciplinary coordination among transplant surgery, hematology, and transfusion medicine teams.