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 kidneydisease, received an ABO-identical, HLA-A,B,DR 5-mismatchedrenal allograft in 1986. Due to graft artery thrombosis andvascular rejection, she lost the kidney 6 months after transplantationand developed HLA antibodies with a panel reactivity of 99%.Despite 5 years on a European waiting list for highly immunizedpatients, she was not offered a second kidney. An attempt toremove her HLA antibodies by plasmapheresis combined with cyclophosphamidetherapy did not succeed. Her 53-year-old HLA-identical, butABO-incompatible sister (blood group A₁) was then accepted asa donor. After immunoadsorption on Biosynsorb-A columns, transplantationwas performed. The post-transplant course was uneventful withoutany signs of rejection. Studies on the anti-A antibody bindingcharacteristics before and after immunoadsorption and aftertransplantation, showed that IgM and IgG antibodies recognizingthe A trisaccharide epitope based on the type 1,2, and 4 coresaccharide chains, were effectively removed by Biosynsorb-Aadsorption, but the column failed to remove anti-A antibodiesrecognizing the A type 3 antigen. These antibodies probablyrequires part of the core saccharide chain for binding. Thepresence of these antibodies did not seem to influence the outcomeof the ABO-incompatible transplantation.