*Abbreviations: ESRD, end-stage renal disease; HLA, human leukocyte antigen; LRD, living related donor; LURD, living unrelated donor; pmp, per million population.
Kidney transplantation has been accepted as one of the best treatment options for end-stage renal disease (ESRD*) patients, but donor shortage has been the major barrier to kidney transplantation in Korea. There has been an increasing discrepancy between the number of kidneys available for transplantation and the number of patients waiting for transplantation since the gradual improvement of the results in kidney transplantations in Korea for the past decade. Although there is a social consensus on brain death, brain death has not yet been accepted legally, and the numbers of living donor kidney transplantations have been very limited. The prevalence of renal replacement therapy (cumulative number of living patients who required renal replacement therapy at the end of the year) has increased steadily, and was reported as 347.9 per million population (pmp) in 1995 and 386.2 pmp in 1996 (Fig. 1). In 1996, the annual incidence of patients on renal replacement therapy (newly developed ESRD patients during the year) was 128.7 pmp, and only 19.8 pmp of this number underwent kidney transplantations. The majority of them received living related donor (LRD) kidneys (58%), followed by living unrelated (30%) and cadaver (12%) donor kidneys (1).
In 1991, we started a donor exchange program at our institution in an effort to solve the problem of organ shortage. The first exchange donor kidney transplantations were performed on two ESRD patients, each of whom had a willing but incompatible related donor. The reason for donor-recipient incompatibility was positive lymphocyte cross-match, and these ESRD patients exchanged their donor kidneys with successful results. Since this success, we have collected incompatible donor-recipient pairs into our database and exchanged their donors. When we performed living donor pool exchange transplants, we chose donors who shared more human leukocyte antigens (HLAs) with the recipient. Our selection criteria of HLA match for kidney donor is more than 2 antigens of HLA class I (A+B) or 1 antigen of HLA class II (DR) match. With these selection criteria, we have found that graft survival of living donor pool exchange kidney transplantation was comparable to that of living unrelated (LURD) or HLA haplo-identical living related kidney transplantation (2). Five-year patient and graft survivals were 91.5% and 82.7% in exchange donor kidney transplantations, 90.7% and 81.5% in LURD kidney transplantations, and 92.4% and 83.9% in HLA haplo-identical LRD kidney transplantations, respectively (P=0.6847 for patient survival, P=0.4795 for graft survival) (Figs. 2 and 3). For the frequency and severity of acute rejection, there was no difference between exchange donor and LURD or HLA haplo-identical LRD kidney transplantation (Table 1). There were 49 patients (44.5%) who experienced acute rejection within the first year of transplantation (Table 2). Two of them lost the graft kidneys due to irreversible acute rejection. There were seven cases of late onset acute rejection, which developed 1 year after transplantation (Table 3). There were 16 graft failures (14.5%) during the study period, and the most common cause of graft failure was chronic rejection (Table 4).
The numbers of simple exchange and living donor pool exchange kidney transplantations in Korea have increased from 4 in 1991 to 38 in 1997 (Fig. 4). These data were obtained from three hospitals (Table 5). There were 86 cases of simple donor exchange and 24 cases of living donor pool exchange. The causes of donor exchange were ABO blood type incompatibility (n=83, 75.5%), poor HLA match in case of transplantation between spouses (n=15, 13.6%), and positive lymphocyte cross-match (n=12, 10.9%) (Table 6). The potential advantages of donor exchange are: (1) it helps relieve stress on donor supply, (2) we can expect short-term and long-term patient and graft survival rates comparable to those of HLA haplo-identical living related donor transplantation, (3) there is a capacity to schedule transplants for medical and personal convenience, (4) there is an emotional gain for donor and recipient families, and (5) we can exclude commercial transplantations with this exchange donor program. On the other hand, there are potential disadvantages in donor exchange, which are: (1) psychological stress to donors and family, (2) conflicts between donors' or patients' families, if there were a significant discrepancy in transplant results, (3) less opportunity for blood group O recipients to find exchange donors, and (4) general risk to most living donors. In fact, we have dealt carefully with donor exchange to avoid interfamilial conflicts. For the simple exchange, simultaneous kidney donor operations were performed, but it is essential to explain the entire procedure and expected results of kidney transplantation before the operation. Almost all the families knew each other, especially for the simple exchange. The problem of reneging has occurred in the living donor pool exchange. After one patient underwent kidney transplantation, a donor hesitated to donate a kidney. Although he later donated a kidney, simultaneous operations are recommended to avoid this reneging problem. It is obvious that patients of ABO blood type O have fewer chances to get exchange donors. There were more than 1,700 kidney transplantations in our hospital, and the proportions of ABO blood type were as follows: A 34.5%, B 30.0%, AB 10.0%, and O 25.5%. This showed no difference from the proportion of ABO blood type in general population. However, in cases of patient who underwent donor exchange kidney transplantation, ABO blood type O recipients were only 15.5% (Table 7). There were no major postoperative complications in exchange donors.
We could achieve some success in reducing stress on donor supply in kidney transplantation, with the exchange donor program in addition to running an unrelated donor program. All kinds of living donors including related, unrelated, and exchange donors could be an option for ESRD patients to relieve the pressure of donor organ shortage, especially in countries where brain death has not been legally accepted. We recommend that the kidney transplantation from living donors should not be excluded as a result of positive lymphocyte cross-match or ABO blood type incompatibility, but instead that these donors be encouraged to exchange among these incompatible groups. However, all of these exchanged donors should undergo careful predonation evaluation procedures as a prerequisite for kidney donation.
1. The Korean Society of Nephrology. Renal replacement therapy in Korea. Korea J Nephrol 1997; 16S2: S1.
© 1999 Lippincott Williams & Wilkins, Inc.
2. Park K, Kim YS, Lee EM, et al. Single center experience of living-unrelated donor renal transplantation in the cyclosporine era. In: Terasaki PI, Cecka JM, eds. Clinical Transplants 1992. Los Angeles: UCLA Tissue Typing Laboratory, 1993; 249.