The impact of donor source, recipient age, pre-operative immunotherapy and induction therapy on early and late acute rejections in children: a report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS).

ABSTRACT

Acute rejection is a frequent event in pediatric transplantation. In addition to graft loss, acute rejection episodes stimulate the development of chronic rejection and inhibit growth in children post-transplantation. In this study, we analyzed our data from 1987 through 1996 to identify acute rejection episodes in children. In 2,520 living donor (LD) transplants there were 2,540 rejection episodes (rejection ratio 1.1), and in 2,579 cadaver donor (CD) transplants 3,653 episodes were observed (rejection ratio 1.32). For LD recipients the first rejection occurred sooner when there was at least one HLA-DR mismatch (RR=1.6, p<0.001) and prophylactic T-cell antibody was not used (RR=1.4, p<0.001). For CD transplants absence of prophylactic T-cell antibody (RR=1.2, p<0.001) and donor age below five years were risk factors (RR=1.5, p<0.001). Late initial acute rejections were seen in 327 of 1,471 patients (22.2%) who were rejection free at one year. At risk for the development of late rejections were children over the age of six years at transplantation (RR=1.7, p<0.001) and children of non-white origin (RR=1.5, p <0.002). For LD transplant recipients in the age range of 0-5 years, irreversible rejection was observed in 8.7% compared to 4.1% for older children (RR=1.46, p<0.001). Similar results for CD transplants were 12.6% versus 6.6% (RR=1.5, p<0.00). The high frequency of rejection episodes in children and the greater irreversibility in younger children suggest pediatric patients may have a more robust immune response. Current ongoing studies in the molecular mechanisms of the pathogenesis of rejection in surveillance biopsies of children may help determine if this hypothesis is valid.