In September, Rex presented his housemate, Peaches, with the gift that keeps on giving -- a desperately needed kidney. Today, the 6-year-old Labrador retriever and 8-year-old English bulldog from Seattle are doing well after their surgeries, performed at the University of California, Davis, Veterinary Medical Teaching Hospital. This was the first successful clinical kidney transplant between unrelated dogs using a new combination of immunosuppressive drugs given to Peaches in order to prevent her body from rejecting Rex's donated kidney, according to Dr. Clare R. Gregory, who performed the surgery. Gregory is an authority on veterinary surgical immunology at UC Davis. Prior to this, only dogs with access to the kidney of a relative could receive a donated kidney at UC Davis. Because of the genetic diversity developed during centuries of breeding, dogs are considered the most difficult species in which to perform transplants of organs from unrelated donors, Gregory said. Peaches had suffered from chronic urinary tract infections, which permanently damaged her kidney. Last summer, she began to show signs of renal failure, thus becoming a candidate for transplant surgery. But like most dog owners, Peaches' owners, Marty and Joanne Modance of Seattle, had no idea where to locate any of the bulldog's siblings, who would be able to provide a genetically matched kidney. When the Modances brought their dogs to UC Davis, Gregory had performed six experimental kidney transplants between unrelated dogs using the new drug combination. Each of the animals had lived more than 100 days, far surpassing the previous 34-day survival record for such surgeries. Peaches provided an opportunity to test the new drug combination clinically -- on a veterinary patient rather than a research animal. Peaches receives doses of an experimental drug combined with the commonly used immunosuppressive drug cyclosporin. She will take these medications for the rest of her life and will undergo periodic exams to make sure her body continues to accept the donated organ. The Modances report that Peaches now seems to have the energy of a young dog. Her housemate, Rex, has fully recovered and should have no future problems functioning on only one kidney. Gregory is hopeful that this new drug combination will provide a surgical option for other dogs whose kidneys are failing. The UC Davis School of Veterinary Medicine receives three or four requests each month for canine kidney transplant surgery, but until now has been able to help only those dogs who have access to a kidney from a related dog.