# Living Donation and Pre-Emptive Transplantation Are More Important Than HLA Matching in Pediatric Kidney Transplantation: Results From a 33-Year Comparative OPTN Study

## TL;DR

This study finds that living donation and pre-emptive transplantation improve pediatric kidney transplant outcomes more than HLA matching.

## Contribution

The study demonstrates that living donation and pre-emptive transplantation outweigh the importance of HLA matching in pediatric kidney transplants.

## Key findings

- Living donor transplants with unfavorable HLA matches had better allograft survival than deceased donor transplants with favorable HLA matches.
- Pre-emptive transplants with unfavorable HLA matches showed better allograft and patient survival than non-pre-emptive favorable HLA matches.
- HLA mismatches were associated with higher delayed allograft function and lower allograft survival overall.

## Abstract

Poorly HLA matched transplants have poorer long-term outcomes, however it is unclear whether living donation or pre-emptive transplantation can counteract the effects of HLA mismatches. We reviewed the long-term outcomes of paediatric kidney transplants with different HLA matches and aimed to identify other factors which may contribute significantly to long-term outcomes. We conducted a retrospective registry analysis of all pediatric kidney transplants from 1987–2020 in the USA from the OPTN Registry. These were analysed by HLA mismatches and compared by pre-transplant dialysis status and donor type. 21,500 patients were included for analysis. Overall, patients with unfavourable HLA matches had higher rates of delayed allograft function and lower allograft survival. However, patients with unfavourable HLA matched transplants from living donors had better allograft survival than patients with favourable HLA matched transplants from deceased donors (79% at 5 years vs. 71%, p < 0⋅01). Patients with pre-emptive unfavourable HLA matched transplants had better allograft and patient survival than patients with non-pre-emptive favourable HLA matched transplants (83% at 5 years vs. 78%, p = 0⋅02% and 98% vs. 96%, p < 0⋅01 respectively). In conclusion, living donation and pre-emptive transplantation have a more significant impact on clinical outcomes and lead to better allograft and patient survival than HLA matching.

Study results from the USA National Registry (1987-2020) on pediatric kidney transplants show living donation and pre-emptive transplantation have better outcomes regardless of HLA matching, with green arrows indicating better results for allograft and patient survival compared to dialysis with favorable HLA. Study by Paessler et al., shown in Transplant International 2025.