Humphreville, Vanessa

Background. Donor-derived cell-free DNA (dd-cfDNA) has emerged as a promising noninvasive biomarker for detecting allograft rejection in solid organ transplantation. However, its diagnostic utility in pancreas transplantation, including in multiorgan recipients, remains underexplored. Methods. We conducted a retrospective analysis of 42 pancreas transplant recipients (38 simultaneous pancreas-kidney, 4 pancreas transplant alone) who underwent for-cause organ biopsy and dd-cfDNA testing between April 2020 and December 2024. dd-cfDNA was measured using the Prospera assay, with a threshold of ≥1% considered high risk and <1% low-risk. Biopsy results were correlated with dd-cfDNA to assess test performance. Results. A total of 50 dd-cfDNA tests and 45 organ biopsies were analyzed. Among simultaneous pancreas-kidney recipients, dd-cfDNA demonstrated a sensitivity of 86.7%, specificity of 52.2%, positive predictive value (PPV) of 54.2%, and negative predictive value (NPV) of 85.7% for rejection. In pancreas transplant alone recipients, all high-risk dd-cfDNA results corresponded to biopsy-proven rejection, yielding 100% sensitivity, specificity, PPV, and NPV. When combining both cohorts, dd-cfDNA testing achieved an overall sensitivity of 88.2%, specificity of 57.7%, PPV of 57.7%, and NPV of 88.2%. Additionally, dd-cfDNA kinetics suggested its potential utility as a surveillance tool posttreatment, potentially reducing the need for closure biopsies. Conclusions. dd-cfDNA is a valuable noninvasive adjunct for monitoring of rejection in pancreas transplant recipients. Further prospective studies are needed to validate these findings and define the optimal role of dd-cfDNA in posttransplant care.

Background. Long-term outcome data by induction type in simultaneous pancreas-kidney (SPK) is limited. Methods. Utilizing the Scientific Registry of Transplant Recipients, we examined all primary SPK transplants between 2000 and 2020, excluding crossmatch-positive recipients. We grouped recipients according to induction regimen into 3 groups: rabbit anti-thymocyte globulin (r-ATG) (n = 5678), alemtuzumab (n = 1199), and interleukin-2 receptor antagonist (IL-2RA; n = 1593). We analyzed the 10-y recipient and composite (kidney and pancreas) graft survival using the Kaplan-Meier survival function. Cox-proportion hazard models were generated to examine the association between induction type, the 10-y recipient, and graft survival. Models were adjusted for recipient age, sex, ethnicity, HLA-mismatch, diabetes type, dialysis dependency, cold-ischemia time, local versus imported organs, panel reactive antibody, steroid maintenance, and Pancreas Donor Risk Index. Results. r-ATG was associated with the lowest 1-y kidney and pancreas rejection rates compared with other agents (P < 0.001). In the univariable analysis, induction type was not associated with recipient (log-rank P = 0.11) or graft survival (log-rank P = 0.36). In the multivariable model for the composite graft survival, alemtuzumab use was associated with 22% increased kidney or pancreas graft loss compared with r-ATG (adjusted hazard ratio, 1.22; 95% confidence interval, 1.05–1.42), whereas IL-2RA use was not a predictor of graft survival. Induction type did not influence recipient survival in the adjusted model. Conclusions. r-ATG use was associated with the lowest SPK rejection rates. Compared with r-ATG, alemtuzumab but not IL-2RA was associated with worse long-term death-censored SPK graft outcome. Our analysis supports the common use of r-ATG for induction in US primary SPK recipients.