Technique may expand kidney transplants

WASHINGTON, Oct 4, 2005 (UPI via COMTEX) -- The results of a new study suggest that a kidney transplantation strategy once deemed unfeasible may enable those in need of kidneys to be matched with compatible donors, which could overcome some of the limitations of organ transplants and expand the donor pool.

More than 63,000 people in the United States currently are awaiting a kidney transplant. About 6,000 of them have a willing donor, but they are incompatible due to their blood types or other issues. The new technique, called kidney-paired donation transplantation, or KPD, seeks to find a match between donor and patient from incompatible donor/recipient pairs.

The strategy involves transplanting a kidney from a donor from the first incompatible pair into the recipient of a second incompatible donor/recipient pair, and vice versa, so each patient winds up receiving a compatible kidney.

KPD potentially could make lifesaving organs available to hundreds or thousands of those in need of a transplant, which could in turn shorten the waiting time for the remaining people on the list.

"This is especially important because it offers hope to patients who have compatibility issues that make it difficult for them to find suitable donors," Dr. Robert Montgomery, director of the Comprehensive Transplant Center at Johns Hopkins University and lead author of the study, said in a statement.

"This study shows that KPD can be done with high degree of success and should be adopted widely with the help of a national KPD list," Montgomery added.

One barrier to transplanting organs from one person to another is certain differences in blood types between donors and recipients can make them incompatible. Another incompatibility that can arise is sensitization to human leukocyte antigens, or HLA, which can develop from pregnancy, previous transplants or blood transfusions.

In the three-year study, reported in the Oct. 5 issue of the Journal of the American Medical Association, Montgomery and colleagues performed KPD on 22 patients, including 10 paired donations and two exchanges involving three people.

The results of the KPD surgeries were comparable to transplants between compatible donors. All of the patients survived, but a transplanted kidney did not function in one of the patients. Although there were five patients who had HLA sensitivity, there were no instances of a type of transplant organ rejection called antibody-mediated rejection, but four patients developed another rejection mechanism known as acute cellular rejection.

Montgomery said a matching system should be established to pair up living donors with compatible recipients. About 36 percent of living donor/recipient pairs will be incompatible due to differing blood types, and 30 percent of the patients waiting for a kidney have HLA sensitization. Montgomery thinks KPD could help 1,000 to 2,000 patients in need of a kidney transplant find compatible donors.

"The only significant gains in finding available kidneys for these patients are likely to come from KPD," he said.

In an accompanying editorial, Drs. Arthur Matas and David Sutherland of the University of Minnesota in Minneapolis wrote that the findings show promise for KPD but said the technique raises several ethical considerations.

One issue is the long-term outcome of the donor. "For example, what if one kidney fails early but the other functions well?" Matas and Sutherland wrote. "Those involved in such programs must pay careful attention to the informed consent process and should be conducting formal follow-up studies of donors."

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