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

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).

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.

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).

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.