Living-unrelated renal transplantation in children: a report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS)
The shortage of cadaver kidneys available for organ donation compared to growing demand has led to an increase in the use of living-unrelated donors (LURD) for renal transplantation (Tx). Results from trials in adults show that 1-year graft survival rates in LURD are similar to living-related donor (LRD) rates and superior to those of cadaver renal donor (CAD) transplants. We report our experience with 38 LURD transplants for children enrolled in NAPRTCS that were performed between 1987 and 1997. Ages of recipients at Tx were 0-5 years (n=8), 6-12 (n=10), and >12 years (n=20). Twenty nine were primary Tx, seven were second Tx, and two were third Tx. HLA antigen data showed that the number of 2-antigen mismatches for each locus was 44.7% for HLA-A, 71.1% for HLA-B, and 55.3% for HLA-DR. There were 7 donor/recipient pairs with a 6-antigen mismatch, 12 pairs with a 5-antigen mismatch, while there were 6 pairs with a 3-antigen match of which 3 pairs had at least one match at each of the A, B, and DR loci. A total of 38 acute rejection episodes occurred in 25 LURD recipients. Among primary grafts the incidence of first acute rejection at 30 d post-Tx was 46% in LURD vs. 29% in LRD and 37% in CAD recipients; at 1 year post-Tx it was 76% in LURD vs. 48% in LRD and 62% in CAD recipients. Acute tubular necrosis (ATN) was reported in four or 10.5% of LURD transplants compared with 5.4% in LRD and 19.0% in CAD recipients. There were 12 LURD graft failures, due to vascular thrombosis (3), acute rejection (2), recurrence of original disease (1), infection (3), and patient death (3). Estimated primary graft survival probabilities (+/- SE) at 12 months post-Tx are 0.825 +/- 0.071 for LURD, compared to 0.911 +/- 0.006 for LRD, and 0.815 +/- 0.009 for CAD. We conclude that data from this study show that LURD Tx in children have a low rate of ATN that is similar to that of LRD Tx. However, LURD Tx have a high incidence of acute rejection, and the graft survival at 12 and 24 months post-Tx is inferior to LRD Tx. There is a high frequency of graft loss due to causes other than rejection, and these may be related to adverse recipient selection criteria.