Passenger Lymphocyte Syndrome in the ABO-Incompatible Kidney Transplant Recipient Receiving Rituximab.

Passenger lymphocyte syndrome is a rare but important disease in which the donor lymphocytes produce antibodies to the red blood cell antigens of the recipient, causing alloimmune hemolysis. It occurs in ABO blood group-mismatched solid-organ and/or bone marrow transplant. We report a case of passenger lymphocyte syndrome occurring after ABO-incompatible kidney transplant. The recipient received rituximab as a desensitization protocol. On posttransplant day 18, the recipient showed a fall in her hemoglobin levels without identifiable bleeding source and an elevation of total bilirubin. Although hemolytic anemia was suspected, schizocytes on the peripheral smear were not observed. Anti-B-type antibodies were detected, and a diagnosis of passenger lymphocyte syndrome was confirmed. The patient was successfully treated with steroid pulse therapy, an increase of mycophenolate mofetil to 2 g/day, and conversion from cyclosporine to tacrolimus. To our knowledge, this is the first demonstration of passenger lymphocyte syndrome in an ABO-incompatible kidney recipients receiving rituximab.