Abstract: TH-PO856
0-ABDR Mismatch Transplants Do Not Confer Additional Immunologic Protection in Non-White Recipients
Session Information
- Transplantation: Clinical - I
November 02, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Transplantation
- 2102 Transplantation: Clinical
Authors
- Caldwell, Jillian, Stanford University School of Medicine, Stanford, California, United States
- Parvathinathan, Gomathy, Stanford University School of Medicine, Stanford, California, United States
- Stedman, Margaret R., Stanford University School of Medicine, Stanford, California, United States
- Ahearn, Patrick, Stanford University School of Medicine, Stanford, California, United States
- Tan, Jane C., Stanford University School of Medicine, Stanford, California, United States
- Cheng, Xingxing S., Stanford University School of Medicine, Stanford, California, United States
Background
In kidney transplants, matching donor and recipient human leukocyte antigen (HLA) alleles reduces allorecognition and eases reliance on immunosuppression. We hypothesize that 0-antigen mismatch transplants provide stronger protection against graft loss in racial minorities in whom systemic barriers to healthcare may explain higher rates of graft failure.
Methods
We included adult, single-organ, US deceased-donor kidney transplants from 2007-2016. We examined time-to-allograft failure (competing risk of death) using imputed Kaplan Meier and Weibull models. Degree of HLA mismatch (0- vs. ≥1- mismatch) was the main exposure. Models were adjusted for potential confounders and included an interaction term between mismatch and recipient race. Additional analyses were stratified by recipient race (white vs. non-white).
Results
We analyzed 102,114 transplants over a median of 5.6 years (16,862 graft loss events, 18,994 deaths). White recipients comprised 59,254 transplants (7628 0-mismatch) vs. 42,860 non-white recipients (1439 0-mismatch). In the cohort, 0-antigen mismatch was associated with improved graft survival (subdistribution hazard ratio [sHR] 0.80, 95% CI [0.75-0.85]) and was similar after adjusting for covariates. In crude models the effect of 0-antigen mismatch was more pronounced in white (sHR 0.78 [0.72-0.83]) vs. non-white recipients (sHR 0.88 [0.79-0.99], interaction p-value 0.03). This was attenuated after adjusting for covariates (sHR 0.78 [0.73-0.84]) vs sHR 0.87 [0.77-0.98], interaction p-value 0.09, Figure 1).
Conclusion
0-antigen mismatch transplants were associated with a 20% risk reduction in graft loss. In non-white recipients the protective effect of 0-antigen mismatch transplants was not enhanced vs. white recipients. This may be due to the degree of mismatch at other HLA alleles and minor antigens, or due to systemic barriers to healthcare borne by minority recipients.
Funding
- Private Foundation Support