Genetic testing to resolve the source of haemolytic antibody in solid organ transplantation.

ABSTRACT

BACKGROUND: Antibody-mediated haemolysis due to passenger lymphocyte syndrome arising in the setting of solid organ transplant can be devastating. Some degree of passenger lymphocyte syndrome is said to occur in up to 10% of ABO mismatched renal transplants, 40% of ABO mismatched liver transplants, and 70% of ABO mismatched heart-lung transplants; a reflection of the number of memory B cells transplanted with the organ. Passenger lymphocyte syndrome is less common with minor red cell antigens but can still be severe. MATERIALS AND METHODS: We review a series of patients who developed passenger lymphocyte syndrome after solid organ transplantation. Conventional serological testing was performed using tube and solid-phase testing. Molecular testing was performed using a gene-chip array. RESULTS: In patients receiving a minor antigen mismatched organ transplant and multiple allogenic red cell transfusions, serological methods proved insufficient to resolve the source of minor blood group antibodies that arose in the aftermath of the transplant. Genetic testing was able to clearly resolve donor and recipient types. DISCUSSION: Passenger lymphocyte syndrome after mismatched organ transplantation is not rare, but the syndrome associated with non-ABO antibodies occurs in a much smaller subset of these cases. The mixtures of organ donor, recipient, and other transfused red blood cells profoundly limit the usefulness of serological testing. Genetic assignment of minor blood types to donor and recipient can guide therapy and inform prognosis.