Transplantation Immunology.pdf - E-Lib FK UWKS

10 Callaghan and Bradley
of pediatric recipients of ABO-incompatible living kidney transplants reported
actuarial 1- and 5-yr graft survival rates of 87% and 85%, respectively, with
100% patient survival (53). There are no significant differences in graft survival
between A- and B-incompatible transplants (52).
Blood group A can be subdivided into A 1 and A 2 types on the basis of the
degree of expression of the A epitope by tissues. Type A 1 is strongly expressed,
and A 2 is only weakly expressed. In Europeans, A 1 is the dominant A blood
group and makes up approx 80% of the total type A population (54). In contrast
to A 1-incompatible kidney transplantation, A 2-incompatible transplants
do not require pretransplant antibody removal if recipients with low anti-A
serum titers are selected. This means that A 2-incompatible cadaveric renal
transplants can potentially be undertaken. One single-center series of A 2-incompatible
cadaveric kidney transplants reported an actuarial 2-yr graft survival of
94% for those patients with a low pretransplant anti-A IgG titer (55). These
results have been difficult to replicate (56), and therefore this approach remains
confined to a small number of units.
At present, a number of factors prevent A 1BO-incompatible living kidney
transplants from achieving widespread acceptance in the Western transplantation
community. These include the relative availability of ABO-compatible
cadaveric and living grafts, the complex and expensive pretransplant plasmapheresis
required, and the inferior early graft survival rates when compared to
ABO-compatible kidney transplants. An alternative approach to dealing with
ABO-incompatible living donors and recipients is to undertake paired donation.
This involves an exchange agreement between two donor–recipient pairs
such that kidneys from two living donors who are both ABO incompatible with
their intended recipients are donated to the reciprocal ABO-compatible recipients.
This has been practiced successfully in South Korea for many years and is
also undertaken in a small number of American centers. Under current UK
legislation, paired donation is illegal (57), but there is hope that new legislation
might enable this approach to be used for ABO-incompatible living donor kidney
transplantation.
4. Recipient Operative Technique
Operative techniques for renal transplantation have remained relatively constant
for the last 40 yr (Fig. 2). The donor kidney is placed extraperitoneally in
either iliac fossa. The renal vein is anastomosed to the external iliac vein, and
the donor renal artery is anastomosed to either the external or internal iliac
artery. Once the venous and arterial anastomoses have been completed, the
vascular clamps are removed to allow perfusion of the graft, and the ureter–
bladder anastomosis is then performed. Insertion of a double-J ureteric stent has
been shown to reduce urological complications, particularly urine leaks (58).