Investigators have had enough success transplanting kidneys in monkeys without using conventional immunosuppression that it may be time to try the approach in people, according to a report in the June issue of Nature Medicine (1999;5:686-693).
Allan D. Kirk, MD, PhD, of the Naval Medical Research Center and colleagues reported that treatment with hu5C8, a CD154-specific monoclonal antibody, prevented acute rejection without apparent toxicity in monkeys who had been transplanted with mismatched kidneys. The effect lasted more than ten months after therapy was terminated, and no other drugs were required to achieve extended graft survival. "Indeed, the use of tacrolimus or chronic steroids seemed to antagonize the antirejection effect," they wrote.
The success with hu5C8 "strongly supports careful study of a regimen based on this antibody to prevent rejection in human allotransplant recipients," the authors concluded.
Almost two years ago, Dr. Kirk and colleagues reported they prolonged allograft survival more than nine months in monkeys who received a combination of hu5C8 and CTLA4-IG (Proc Natl Acad Sci USA 1997;94:8789-8794) (see Transplant News Network for October 15, 1997).
In a letter printed on May 27 in Nature, scientists who cloned Dolly and two other sheep by nuclear transfer reported that the sheep have genetic material that appears to be older than the sheep themselves (1999;399:316-317). Paul G. Shiels and colleagues at PPL Therapeutics and the Roslin Institute in Scotland said that the three sheep have shorter telomeres than age-matched control sheep. Dolly, who was cloned in 1996 from a six-year-old sheep, showed telomere loss of about 20%. While some observers argued that the findings raise important issues about the future of cloning, others said that the results are too preliminary to allow conclusions to be drawn.
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