How an ABO-incompatible graft may contribute to its survival by phenotype-specific glycosylation of the host. A hypothesis.

In contrast to non-nucleated ABO(H)-incompatible red cells, which when transfused to an HLA-compatible blood group O(H) recipient undergo destruction within minutes, such humoral, hyperacute rejection caused by anti-A/B-antibodies, occurs relatively rare in transplantations of highly nucleated, metabolically active solid organs, and it is extremely rare or uncommon in liver transplantations. Moreover, a case of selective disappearance of donor-specific antibodies after liver transplantation has been reported. It appears that transplants always maintain their original, phenotype-specific metabolic properties, and expanding the concept of glycosidic exclusion, the phenotype determines simultaneous glycosylation of the cell surfaces and immunoglobulins. Thus, it may be assumed that a transplanted ABO-incompatible, metabolically active tissue may use its phenotype-specific enzymatic equipment to contribute to a compatible environment by consistent glycosylation of complementary sites of the plasma proteins and the B-cell surfaces of a HLA-compatible recipient.