Characterization of the anti-A antibody binding in an ABO-incompatible living donor renal transplantation.

A 57-year-old female, blood group B, with polycystic kidney disease, received an ABO-identical, HLA-A,B,DR 5-mismatched renal allograft in 1986. Due to graft artery thrombosis and vascular rejection, she lost the kidney 6 months after transplantation and developed HLA antibodies with a panel reactivity of 99%. Despite 5 years on a European waiting list for highly immunized patients, she was not offered a second kidney. An attempt to remove her HLA antibodies by plasmapheresis combined with cyclophosphamide therapy did not succeed. Her 53-year-old HLA-identical, but ABO-incompatible sister (blood group A1), was then accepted as a donor. After immunoadsorption on Biosynsorb-A columns, transplantation was performed. The post-transplant course was uneventful without any signs of rejection. Studies on the anti-A antibody binding characteristics before and after immunoadsorption and after transplantation, showed that IgM and IgG antibodies recognizing the A trisaccharide epitope based on the type 1, 2, and 4 core saccharide chains, were effectively removed by Biosynsorb-A adsorption, but the column failed to remove anti-A antibodies recognizing the A type 3 antigen. These antibodies probably requires part of the core saccharide chain for binding. The presence of these antibodies did not seem to influence the outcome of the ABO-incompatible transplantation.