The impact of human leukocyte antigen mismatching on sensitization rates and subsequent retransplantation after first graft failure in pediatric renal transplant recipients.

BACKGROUND: U.S. allocation policies currently place less emphasis on human leukocyte antigen (HLA) matching in pediatric kidney transplant candidates to minimize dialysis time. The impact this may have on pediatric recipients after graft failure has not been extensively examined.
METHODS: Using the Scientific Registry of Transplant Recipients database, we examined HLA sensitization after graft loss and regraft survival of all pediatric primary kidney transplant recipients younger than 18 years transplanted between 1990 and 2008, stratified by HLA-DR mismatch (MM) of first and second kidney transplant.
RESULTS: Of 11,916 pediatric primary kidney transplant recipients, 2704 were relisted after first graft failure. 1847 received a retransplants, and 857 remained on the waiting list. Mean % panel reactive antibody increased from 6% to 45% for retransplant and from 8% to 76% for those on the waiting list. The degree of sensitization and waiting time to retransplantation increased with DR MM at first kidney transplantation. Two DR MM statuses at first transplant were associated with a 20% reduction in the hazard of receiving a retransplant (hazard ratio, 0.80 for 2 vs. 0-1 DR MM; P<0.001). Five-year retransplant graft survival was associated with the number of HLA MM at first and second kidney transplant. Retransplant graft survival was similar in the circumstance of a 0-1 DR MM living donor following a deceased donor, and the converse.
CONCLUSION: In pediatric recipients, increasing number of initial HLA-DR MMs is associated with HLA sensitization, longer waiting time, decreased rate of retransplant, and decreased regraft survival. Consideration of DR matching at first transplant may mitigate these risks.