Post-Kidney Transplant Anemia as a Result of Passenger Lymphocyte Syndrome by Rhesus Antibodies - A Rare Etiology for a Common Finding

Posttransplant Anemia (PTA) is a common finding, often multifactorial. Some atypical etiologies can be masked by the usual causes, resulting in non-solving anemia and compromising graft viability and host recovery. An immune-mediated hemolysis can develop in solid or bone marrow graft recipients in the presence of ABO-minor mismatch or, more rarely, other blood groups mismatches, like Rhesus (Rh) system. This condition, known by Passenger Lymphocyte Syndrome (PLS), occurs after the transfer of donor’s viable B-lymphocytes with the transplanted organ, which leads to the production of antibodies (Ab) against recipient red blood cells (RBC) antigens (Ag). PLS should be considered even when the PTA etiology seems obvious or when there are no apparent reasons for suspecting it. We review a case of PLS after kidney transplantation, caused by an Rh(D) mismatch.