Antibody depletion prolongs xenograft survival

Background. The lack of human organ donors has prompted a renewed interest in xenotransplantation. Xenoantibody is believed to be an initiator of a complex cascade of events ultimately ending in rapid xenograft destruction. Methods. Cell-free plasma was obtained via plasmapheresis of the recipient canine. This plasma was then perfused in an ex vivo fashion through either the donor (pig) spleen or liver, allowing for specific antidonor antibody deposition in the 'screening' organ, and is then returned to the animal. A porcine kidney is then transplanted to the dog, and the outcome is observed. Results. We have used specific antibody depletion to prolong xenotransplant survival. In the untreated pig-to-dog combination, the transplanted pig kidney is destroyed by the dog in 13 minutes (mean). Adsorption using either the donor spleen or liver resulted in an increase of 3.4 hours and 7.8 hours of graft survival, respectively. The histologic picture of rejected kidneys after adsorption shows a modified form of rejection. Conclusions. In this pig-to-dog xenograft combination, xenoantibody adsorption allows for prolonged graft survival as compared with control animals. Subsequent xenograft destruction occurs but in a modified manner.