Abstract: SA-PO473

Association of HLA-DR and DQ Mismatches and Acute Rejection in Living Donor Kidney Transplant Recipients

Session Information

Category: Transplantation

  • 1702 Transplantation: Clinical and Translational

Authors

  • Onete, Daniel, Western University of Canada, London, Ontario, Canada
  • Xu, Qingyong, London Health Sciences Centre, Oakville, Ontario, Canada
  • Suri, Rita, Université de Montréal, Montreal, Quebec, Canada
  • Gunaratnam, Lakshman, London Health Sciences Centre, Oakville, Ontario, Canada
Background

Previous studies show that HLA incompatibility is associated with greater risk of graft failure in deceased-donor kidney transplant patients. However, whether HLA-mismatches are important in low-risk recipients of living donor kidneys in the era of modern immunosuppression is unclear. Given that de novo, donor specific antibodies against Class II HLA (DQ or DR) are associated with poor long-term outcomes in deceased donor transplant recipients, we hypothesized that having 3-4 (vs. 0-2) HLA DQ/DR mismatches would be associated with acute rejection in low-risk, living donor kidney transplant recipients.

Methods

We conducted a retrospective cohort study of all cross-match negative, transplant-naive, living donor kidney transplant recipients at our center from 2006-2016. Electronic charts were reviewed for demographics, comorbidities, HLA genotype and outcomes. HLA genotyping was performed using molecular typing. The primary outcome was acute rejection within 1-year post-transplant, and was defined as either: definitive biopsy-proven T-cell mediated rejection (TCMR) (Banff criteria), or as borderline TCMR on biopsy that was treated with pulse steroids and/or anti-thymocyte globulin. The secondary outcome was serum creatinine at 1 year post-transplant. Outcomes were compared between patients with 0-2 vs. 3-4 HLA-DR/DQ mismatches.

Results

Of the 178 recipients transplanted with living donor kidneys from 2006-2016, 6 were excluded due to incomplete follow-up data. In total, 124 (72%) and 48 (28%) received 0–2 and 3–4 HLA-DR/DQ mismatched kidneys, respectively. We observed 27 definitive rejections and 25 treated borderline rejections within 1-year post-transplant. Patients with 3–4 HLA-DQ/DR mismatched kidneys had a statistically significant greater risk of acute rejection (odds ratio = 3.43 [95% CI 1.69-6.94]; p=0.0008). This association persisted when we limited the primary outcome to definitive rejection (odds ratio = 3.39 [95% CI 1.45-7.89]; p=0.0053). There was no significant difference between groups in the mean 1-year serum creatinine (122.4 ± 5.889 vs. 117.0 ± 4.035; p=0.59).

Conclusion

In this single center study, we found that greater HLA-DR and DQ mismatches were associated with increased risk of acute rejection at 1-year after living donor kidney transplant.

Funding

  • Government Support - Non-U.S.