Researchers Develop Safer Way To Prevent Transplant Rejection
Two Navy researchers said Tuesday they have devised a way to prevent the body from rejecting transplants without suppressing the whole immune system and leaving the recipient vulnerable to infections.
Preliminary experiments on monkeys suggest the treatment could also free organ recipients from the need to take anti-rejection drugs for the rest of their lives, thereby greatly reducing the cost and the complications of transplants, the researchers said.
Lt. Cmdr. Allan D. Kirk and Capt. David M. Harlan of the Naval Medical Research Institute reported at a news conference here that they used synthetically created antibodies to deactivate immune cells that would normally trigger rejection of foreign organs. A monthlong treatment with the antibodies also prevented the body from recognizing the donor organs as foreign when treatment was stopped, they said.
Two monkeys treated in this fashion after receiving grossly mismatched donor kidneys have survived for more than 150 days with no further treatment and no signs of rejection, they report in the current Proceedings of the National Academy of Sciences.
The two Navy doctors, who hope to begin trials in humans within a year, say the new drugs could be in routine clinical use within five years. “There is no doubt that this works,” Kirk said. “But we have to see how they would interact with other drugs that would be used in transplants in humans.”
“This is quite an exciting finding,” said Dr. Hans Sollinger, a transplant surgeon at the University of Wisconsin Medical Center who was not involved in the research. “I consider this a very promising start” toward work in humans.
Currently, donated organs have to be closely matched to the recipient immunologically so that they are not immediately rejected. Even then, patients must receive expensive anti-rejection drugs for the rest of their lives.
Those drugs suppress the entire immune system, leaving the patient susceptible to a broad variety of viral and bacterial infections. The drugs themselves also produce complications ranging from diabetes and thinning of the skin to osteoporosis and kidney failure.
At least in part because of problems involving compatibility of donor organs, nearly 4,000 Americans died in 1996 while awaiting transplants, according to the United Network for Organ Sharing. An estimated 50,000 are on waiting lists for donor organs.