Dutch Living Donor Kidney Exch
By Marlene Busko
Medscape Medical News
January 11, 2007 ??A national
exchange program in the Netherlands found successful matches for 49% of 146
living kidney donor-recipient pairs who had incompatible blood types or positive
crossmatches. These 30-month results from a program
embarked on in 2004 are reported in the December 27, 2006 issue of
Transplantation.
"The full-hearted
cooperation between 7 university transplant centers, including their [human
leukocyte antigen] HLA laboratories, has resulted in a high number of
participants, which is absolutely necessary for such an excellent success rate,"
the study's lead author, Marry de Klerk, MD, from the Erasmus Medical Center, in
Rotterdam, the Netherlands, told
Medscape.
Willing but Mismatched
Donors
The group writes that in the
Netherlands, over the past 3 decades, the median wait time for a kidney
transplant has increased from under 1 year to 4 to 5 years. The favorable
outcome of living kidney donation and the development of laparoscopic donor
nephrectomy have increased the attractiveness of this procedure. Yet some
transplant candidates and potential living kidney donors have either
incompatible ABO blood types or have antibodies (are sensitized) to donor HLAs,
resulting in a positive crossmatch. Patients might have a high level of
sensitization ??a high panel reactive antibody (PRA) ??due to
transfusions, pregnancy, or previous transplants. A protocol of using either
plasmapheresis or immunoabsorption to remove the antibodies, followed by
immunoglobulin therapy, has been used for such patients.
A less expensive strategy is a paired donor
kidney exchange program, where, for example, 2 incompatible donor-recipient
pairs are matched so that the kidney from one pair is given to the transplant
candidate in the second pair, and vice versa. In the Netherlands, all 7 kidney
transplant centers embarked on such a program in 2004. This article examines the
30-month results.
From January 2004 until June
2006, 146 incompatible donor-recipient pairs participated in the living donor
kidney exchange program. (No incompatible donor-recipient pairs chose not to
participate, Dr. de Klerk said.) Recipients had a median age of 51 years (range,
15 ??73) and had been on a cadaveric kidney transplant wait list for a
median of 13 months (range, 0 ??172 months); donors had a median age of 52
years (range, 26 ??77). Of the donor-recipient pairs, 69 transplant
candidates (48 women and 21 men) had a positive crossmatch with their potential
donors, and 77 transplant candidates (31 women and 46 men) had an ABO blood type
that was incompatible with their potential donors. The largest donor group
consisted of partners (86/146, 59%).
Every 3
months, the participants could be registered for a computer match; during the
study period, 10 match procedures were performed (combinations of 2
donor-recipient pairs until 2005, and combinations of up to 3 donor-recipient
pairs since then). Allocation criteria were blood type (first identical and then
compatible), match probability (the recipient with the lowest chance of finding
a donor, based on compatible ABO type and acceptable HLA antigens within the
donor population, was ranked first), wait time, and donor age. The 7 transplant
centers had a common protocol that prescribed that the donor travel to the
recipient's center and the surgical procedures take place
simultaneously.
High Success
Rate
Matching based on ABO blood types and
unacceptable HLAs identified 1019 possible matches for 122 donor-recipient
pairs, with no potential solutions for 24 pairs. Selection on the basis of match
probability resulted in 72 new match combinations. The success rate was
significantly higher in the positive-crossmatch group than in the
incompatible-ABO-blood-type
group.
Successful Matches Among Incompatible
Donor-Recipient Pairs
Positive-Crossmatch Group
|
Incompatible-ABO-Blood-Type Group
|
P
|
44/69
|
28/77
|
.0015
|
After 3 attempts, the chance of finding a new donor
in both categories of patients became remote. In both groups, PRA influenced the
success rate, but a substantial number of highly sensitized patients could still
be helped.
The blood type non-O-to-O
combination was difficult to match. However, for 9/53 (17%) of these couples,
matching couples were found in the positive-crossmatch group, allowing 18
transplants to be made. "This demonstrates that combining 2 categories of
donor-recipient pairs increases the efficiency of a paired donor exchange
program," the group writes.
From the 72 matched
pairs, 57 transplants have already been performed, and 5 procedures are planned,
the team writes.
They conclude: "Paired living
donor kidney exchange is an excellent solution and the first choice for a
substantial number of recipients who cannot identify a compatible donor because
of an ABO-blood-type or crossmatch incompatibility." For "unlucky couples" for
whom a suitable match cannot be found, alternative strategies need to be
explored, they add.
"The message is that
logistic solutions should be the first option for incompatible donor-recipient
combinations," Dr. de Klerk said, adding that the program is ongoing and they
are happy with the 3-year results.
Transplantation.
2006;82:1616-1620.
|