Presence of glycosyltransferase inhibitors in the sera of patients with long-term surviving ABO incompatible (A2 to O) kidney grafts

Summary. In the sera of blood group O recipients with long-term surviving blood group A2 kidney grafts, inhibitors of A-glycosyltransferase (α-3-N-acetyl-D-galactosaminyl transferase) have been identified in four out of six patients. The inhibitors seem to be of IgG antibody nature and do not appear until at least 1 year after transplantation. The inhibitors are also active against B-transferase (α-3-D-galactosyl transferase) as well as against A-glycosyltransferase of pig origin. The importance of these A-glycosyltransferase inhibitors is not clear. They may have a modifying effect on the antigenic expression of the graft. The immunogenicity of soluble glycosyltransferases is well known and the development of antibodies against them might prevent their enzymatic activity.