Implications of the Kidd blood group system in renal transplantation.

The association of the Kidd blood group system with hemolytic transfusion reactions and hemolytic disease of the newborn is well known. The Kidd antigens, which are localized to the HUT/UT-B urea transport protein, are found on red blood cells and the endothelial cells of the blood vessels of the medulla of the kidney. Recently it has been suggested that these antigens might play a role as minor histocompatibility antigens in renal transplantation. In the current case, the appearance of an anti-Jk(b) 10 years after renal transplantation associated with early renal allograft rejection further supports the potential importance of these antigens in renal transplantation and allograft rejection.