The advance substantially reduces the need for anti-rejection drugs, which patients normally take for life, and paves the way for animal-to- human "xenografts", where rejection is the key obstacle.
Sir Roy Calne, emeritus professor of surgery at Cambridge University and a pioneer of transplant medicine, said the new treatment promises to produce dramatic improvements in the health of patients. "I've not seen a group of patients do as well as this in 40 years," he said. "Although I would never use the word `breakthrough', it is a significant improvement."
The treatment involves injections with a synthetic antibody, called Campath, before the operation so that the body's immune defences - which cause rejection - are temporarily emasculated.
"If xenotransplants are going to be successful almost certainly an antibody with this kind of an effect would be a useful adjunct, but how useful we don't know. In xenotransplantation, rejection is more of a problem," Sir Roy said.
A clinical trial involving 30 kidney-transplant patients who were treated with Campath before surgery has shown that over two years they can survive on just just one anti-rejection drug, at half the normal dose.
Normally, transplant patients take at least three anti-rejection drugs at full dose,risking side-effects such as cancer and brittle-bone disease. The drugs usually include steroids - which stunt the growth of children and cause other long-term problems - cyclosporin, which can cause unwanted hair growth, and Imuran, an anti-cancer drug that can damage bone marrow. Campath is already used in other treatments without serious side-effects.
The research, previewed last night on BBC1's Nine O' Clock News, will be published in the Journal of Transplantation and describes how the antibody temporarily clears the immune system's lymphocyte cells from the bloodstream, allowing the organ transplant to go ahead without fear of immediate rejection. By the time the lymphocytes begin to return more than a month later they do not appear to be able to recognise the new organ as a "foreign body" that has to be attacked.
"What is new is the use of the antibody as a pre-emptive strike. If you use the analogy of war, this would be to take out the combative troops that are around at the time of the graft," Sir Roy said. "As the new reinforcements come along, they are brainwashed to be friendly towards the graft."