AUXILIARY LIVER ALLOGRAFTING AND XENOGRAFTING IN THE NONHUMAN PRIMATE

Auxiliary liver transplantation has been performed in the baboon using allografts (n=8) and concordant xenografts hom donor African green mo nkeys (n=8). The native portal vein was ligated in all cases and the n ative common bile duct was ligated in 5 cases. The immunosuppressive t herapy used was identical in both the allografts and xenografts and co nsisted of triple drug therapy (cyclosporine, cyclophosphamide, and me thylprednisolone), all at dosages consistent with clinical use, During the determination of the surgical technique to be applied, there were 5 early failures (3 allografts, 2 xenografts), and 2 deaths at 10 and 20 days from multiorgan failure and sepsis, respectively (xenografts) , The remaining 9 baboons (5 allografts, 4 xenografts) were electively euthanized at 16-62 days (allografts) and 35-120 days (xenografts). H yperacute rejection or antibody-mediated rejection was not seen in the grafted livers, Episodes of acute cellular rejection occurred in the majority of animals within the first 30 days and recurred in the longe r-term survivors, but could be controlled by bolus therapy with intrav enous methylprednisolone. Satisfactory donor liver function was confir med using a number of tests, including scintigraphy in 3 cases. We con clude that auxiliary liver transplantation using a closely related don or species is feasible in baboons and might be extended to humans with terminal liver failure, A baboon-to-man auxiliary liver graft may ser ve as a ''bridge'' until either a human cadaver donor liver became ava ilable or native liver function recovers in patients with fulminant he patic failure.