Presence of an inhibitor of glycosyltransferase activity in a patient following an ABO incompatible liver transplant

The contribution of the liver to plasma ABO glycosyltransferase activity has been studied in a group O individual transplanted with a liver from a group B donor. The B transferase activity present in the post-transplantation plasma was negligible. However, a potent B transferase inhibitor, absent from the pretransplantation plasma, was present after transplantation. The inhibitor was present in the excluded fraction following Sephadex G-25 gel filtration, but was retained by a protein A-Sepharose column, suggesting that it was an IgG antibody. This inhibitor was also effective in reducing A transferase activity.