ABO antigen expression in graft tissue: is titration against donor erythrocytes relevant?

ABO-incompatible living donor renal transplantation has become an accepted treatment for end-stage renal disease. Two main factors appear to be important when crossing the ABO barrier, the donor organ A/B antigen expression and the amount of recipient anti-A/B antibody. Antigen expression depends on the ABO blood group and subgroup and may vary in different tissues and cells. The amount of recipient anti-A/B antibody, determined by titration, is very variable. One major drawback with titration is the lack of conformity between different laboratories, making comparisons difficult. For clinical use, the anti-A/B antibody titration technique has to be simple, rapid, and cheap, in addition to being accurate. Although there is a need for more standardized procedures for determination of ABO antibodies, existing techniques are sufficient in the clinical care of patients. To illustrate the variation in susceptibility of different graft tissues to ABO antibodies, in this paper we describe a case of an ABO-incompatible combined liver and kidney transplantation.