A 35-YEAR-OLD man, the first person in the world to receive a baboon's liver, died after two months of the transplant. Though he was found to be HIV-infected, he had reportedly not developed AIDS. Surgeons at the University of Pittsburgh Medical Centre plan to continue experimental transplants as rejection of the liver had not been the cause of death. In fact, within a month of the transplant the baboon's liver had tripled in size on its own to meet the metabolic needs of the recipient. "No one knows why the liver grew or why it stopped growing," said Anthony J Demetris, the pathologist who performed the autopsy.