Passenger lymphocyte syndrome after living-donor kidney transplantation with minor ABO incompatibility: a case report

Abstract

Passenger lymphocyte syndrome (PLS) is an uncommon, immune-mediated hemolytic disorder that may develop after solid organ or hematopoietic stem cell transplantation when minor ABO incompatibility exists between donor and recipient. It is caused by donor-derived viable B lymphocytes producing antibodies against recipient erythrocyte antigens.

We describe a 28-year-old female (recipient blood group A RhD-positive) who underwent living-donor kidney transplantation from her father (donor group O RhD-positive). Two weeks post-transplant, she presented with fatigue, right shoulder and scapular pain. Laboratory evaluation demonstrated severe normocytic anemia (hemoglobin 49 g/L), elevated lactate dehydrogenase and bilirubin levels, undetectable haptoglobin, and a strongly positive direct antiglobulin test (IgG and C3d). Elution studies identified anti-A antibodies bound to red blood cells, suggestive of PLS. Imaging excluded bleeding but revealed thrombosis of the right internal jugular and brachiocephalic veins. Management included plasma-exchange (PEX), high-dose corticosteroids, and transfusion of irradiated donor-type (group O RhD-positive) red cells. The patient showed progressive hematologic recovery with normalization of hemolytic indices and preserved graft function at hospital discharge.

PLS should be considered in the differential diagnosis of acute hemolytic anemia occurring within the first three weeks after transplantation involving minor ABO mismatch. Early recognition through direct antiglobulin testing (DAT) is essential to guide transfusion strategy and immunomodulatory therapy. Combined PEX and corticosteroid treatment effectively reduced antibody-mediated hemolysis. Routine post-transplant DAT screening may facilitate prompt diagnosis and improve clinical outcomes in renal transplant recipients.