Passenger lymphocyte syndrome in ABO and Rhesus D minor mismatched liver and kidney transplantation: A prospective analysis

The increasing demand for solid organs has necessitated the use of ABO and Rhesus (Rh) D minor mismatched transplants. The passenger lymphocyte syndrome (PLS) occurs when donor lymphocytes produce antibodies that react with host red blood cell (RBC) antigens and result in hemolysis. Our aim was to evaluate prospectively the role of PLS in post transplant anemia and hemolysis in ABO and RhD minor mismatched recipients of liver and kidney grafts and to study the association of PLS with donor lymphocyte microchimerism. We examined 11 liver and 10 kidney recipients at Day +15 for anemia, markers of hemolysis, direct antiglobulin test and eluates, and serum RBC antibodies. Microchimerism was determined in peripheral blood lymphocytes by genotyping of simple sequence length polymorphisms encoding short tandem repeats. Immune hemolytic anemia and anti-recipient RBC antibodies were observed in 2 out of 11 liver (18.2%) and 2 out of 10 kidney (20%) transplants. RBC antibody specificity reflected the donor to recipient transplant, with anti-blood group B antibodies identified in 2 cases of O to B and 1 case of A to AB transplants while anti-D antibodies were detected in 1 case of RhD-negative to RhD-positive transplant. Donor microchimerism was found in only 1 patient. In conclusion, passenger lymphocyte mediated hemolysis is frequent in minor mismatched liver and kidney transplantation. Recognizing PLS as a potential cause of post transplant anemia may allow for early diagnosis and management to decrease the morbidity and mortality in some patients.