Influence of HLA mismatch between donors and recipients on postoperative outcomes in cadaveric lung transplantation.

Objectives: Generally, HLA matching between donors and recipients is not performed in lung transplantation (LTx). Therefore, whether HLA mismatch between donors and recipients (D/R mismatch) influences postoperative outcomes after LTx remains uncertain. In this study, we investigated the influence of D/R mismatch on postoperative outcomes after cadaveric LTx (CLT).

Methods: A total of 140 CLT procedures were performed between 2012 and 2020. After excluding 5 recipients with preformed DSA and 1 recipient undergoing re-LTx, 134 recipients were enrolled in this retrospective study. The postoperative outcomes were compared between recipients with higher and lower D/R mismatches.

Results: The median D/R mismatch (A/B/DR loci) was 4.0 (range, 1-6). When dividing these 134 recipients into two groups (H group [D/R mismatch ≥ 5, n = 57] and L group [D/R mismatch ≤ 4, n = 77]), there were no significant differences in the patient backgrounds. The lengths of hospital and intensive care unit stays were similar (p = 0.215 and p = 0.37, respectively). Although the overall survival was not significantly better in the H group than in the L group (p = 0.062), chronic lung allograft dysfunction-free survival was significantly better in the H group than in the L group (p = 0.027). Conversely, there was no significant difference in the cumulative incidence of de novo donor-specific anti-HLA antibodies (dnDSAs) between the two groups (p = 0.716).

Conclusions: No significant difference in dnDSA development was observed between patients with higher and lower D/R HLA mismatches. Given the favorable outcomes in the high HLA mismatch group, CLTs can be performed safely in recipients with high D/R HLA mismatches.