Allograft Injury and Outcomes in African American Lung Transplant Recipients

• Published in: The Journal of heart and lung transplantation Vol. 39; no. 4; pp. S55 - S56
• Main Authors: Agbor-Enoh, S., Charya, A., Jang, M., Luikart, H., Shah, P., Matthews, J., Brown, A.W., Timofte, I., Fideli, U., Kong, H., Bhatti, K., Marishta, A., Yang, Y., Tunc, I., Berry, G., Marboe, C., Iacono, A., Nathan, S., Khush, K., Orens, J.B., Valantine, H.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-04-2020
• ISSN: 1053-2498; 1557-3117
• DOI: 10.1016/j.healun.2020.01.1242

African American patients (AA) have poorer outcomes than White patients (W) after heart and kidney transplant. Little is known about differential outcomes in lung transplantation (LTx). This study compares allograft injury and chronic allograft dysfunction (CLAD) in AA and W LTx.
The 469 LTx enrolled in two multicenter prospective cohort studies were categorized by self-reported race. Outcomes: Time from transplant to CLAD-free survival adjudicated by a committee using ISHLT standard definitions. Measure: Serial post-transplant plasma samples (n=2152) were assayed for %ddcfDNA by shotgun sequencing. Analyses: Baseline characteristics, post-transplant %ddcfDNA trends, tacrolimus trough levels and CLAD-free survival were compared between AA and W.
LTx recipients were 79% W and 14 % AA. Donor-recipient race mismatch was more commonly observed for AA than for W (75.0% vs. 27.3%, p<0.01). Other baseline characteristics were similar in AA and W. During follow-up (median 19.8 months, IQR = 10.7 - 36.9), tacrolimus trough levels were similar in AA and W (9.2±0.1 vs. 9.0±0.1, p = 0.19). However, AA showed 1.5X higher rejection rates (HR = 1.6, CI = 1.0 - 2.6), and higher %ddcfDNA levels particularly beyond 6 months when maintenance immunosuppression doses were lowest (Figure A). Higher %ddcfDNA trends correlated inversely with CLAD-free survival; AA developed CLAD and/or died 18.8 (mean) months before W (Figure B). Similarly, acute rejection was inversely with CLAD-free survival.
AA LTx show higher allograft injury and poorer CLAD-free survival than W LTx despite equivalent tacrolimus blood levels. Studies to understand the mechanisms of allograft injury and poor outcomes in AA are warranted across all solid organ transplants.