Red cell compatibility testing in baboon xenotransplantation.

BACKGROUND

Although baboon ABO group and human anti-baboon heteroagglutinin (HA) titers have been considered in the selection of baboon donors for clinical hepatic xenotransplantation, the biologic role of these antibodies is not yet known. However, because of the potential importance of ABO hemagglutinins, a method for baboon ABO group determination is described, as are the titers of HA observed in both baboons and normal human donors.

STUDY DESIGN AND METHODS

The ABO group of 62 baboons was determined by modified reverse typing. Baboon sera were heated and absorbed with human group O red cells. Reverse typing was then performed by standard techniques. HA titers at room temperature (RT) and in the antiglobulin test (AGT) were assessed in 10 baboons by using human red cells and in 33 normal donors by using baboon red cells.

RESULTS

Ten (16%) baboons were group A, 29 (47%) were group B, 23 (37%) were group AB, and none were group O. In tests using human group O red cells, HA titers in 10 baboons ranged from 1 to 32 at RT and from negative to 64 in the AGT. All 33 normal human sera contained anti-baboon HA. Under a hemagglutination scoring system, group A persons had the lowest HA scores (17 +/- 15 at RT, 31 +/- 19 in the AGT), and group B persons had the highest HA scores (67 +/- 4 at RT, 85 +/- 9 in the AGT).

CONCLUSION

Baboon ABO group can be easily determined by modified reverse serum typing. Both baboons and humans possess HAs of variable titer. Among humans, titers appear to be highest in group B individuals and lowest in group A. Additional studies are needed to determine the clinical significance of these antibodies.