Renal transplantation across the ABO barrier.

Some patients with end-stage renal disease do not have suitable living related donors due to ABO incompatibility. Crossing the ABO barrier has long been considered an absolute contraindication to kidney transplantation. Although transplantation using A2 kidneys has been performed in a few centers over the past two decades with variable success, the presence of blood group antigens can cause immediate or early graft loss due to preformed antibody-mediated hyperacute rejection. Over the past few years, novel protocols designed to reduce anti-donor antibodies have allowed successful transplantation across the ABO barrier. This requires careful preoperative conditioning, which will be described in this article.