Nearly 5,000 people are on the waiting list for kidney transplants in Britain; fewer than 2,000 kidneys become available each year from patients dying from head injuries and other conditions that leave the kidneys in good condition. Only 100 or so operations are done each year using kidneys taken from living relatives of the patients needing a kidney. By contrast, in the United States around one in every six transplant operations uses a kidney from a living donor.
Surgeons in Britain have several objections to the use of living donors. Research on transplants using organs taken after death has consistently shown the importance of matching the tissue types of donor and recipient. The closer the match, the more likely the operation is to be successful in both the short and long term. By no means all blood relatives have closely matching tissue types. When a kidney patient needs a transplant, tests can be done on the family to find whose tissue types match most closely - often a brother or sister. This ideal donor may then come under emotional pressure from the rest of the family to agree to undergo the small physical risk of having a kidney removed. Even when an offer comes freely from, say, a parent of a young kidney patient, surgeons are often worried about the emotional consequences should the operation fail. British surgeons are very wary of using unrelated donors: in the 1980s there were several scandals when claims were made that donors had been paid large sums for their kidneys.
The surprising finding from the research in California is that close matching of the tissue types seems far less important with live spouse donations than with kidneys taken after death. Analysis of the results of 368 kidney donations from spouses showed that the results after three years were very similar to those of matched donations from brothers, sisters or parents, and the success rate was 85 per cent as opposed to the 70 per cent from kidneys taken after death. Surgeons offer two explanations. First, they think that as many as 10 per cent of kidneys taken after death may be damaged (though this is not apparent at the time). Secondly, they think that when a kidney has been donated by a relative the patient is more likely to take drugs exactly as instructed.
In practical terms, most patients on the waiting list for kidney transplantation are adults and around half of them are likely to be married. The Californian surgeons believe that possibly half these spouses would be willing to become donors once the risks and benefits were fully explained. But the mortality rate of giving away one's kidney is around one in 3,000, and the emotional consequences are difficult to predict.