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

In comparison with non-nucleated ABO-incompatible red cells, which undergo immediate destruction when transfused to a blood group O(H) recipient, a nucleated, metabolically active tissue transplanted from that same donor to an HLA-compatible recipient of the same blood group shows, taking into account all therapeutic measures, relatively long survival. 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.