Increased Cell Free DNA Levels in African American Patients Early after Heart Transplantation

Abstract

African American (AA) patients are at risk for increased rates of rejection after heart transplantation (HT). We compared cell-free DNA (cf-DNA) levels after HT by recipient race. This was a retrospective analysis of 96 HT recipients from the Genomic Research Alliance for Transplantation (GRAFT) Registry, of which 63 patients had cf-DNA values. Cf-DNA values were compared by race with an exponential decay model and Kaplan-Meier (KM) analysis was performed to compare time-to-first rejection. Compared to non-AA patients, AA recipients had a similar prevalence of diabetes and hypertension, proportion of males, and donor characteristics. AA recipients had higher cf-DNA values compared to non-AA recipients for the first five days following transplant (8.3% vs. 3.2% p=0.001 Table 1/figure 1). The stable state cf-DNA values decayed rapidly for AA patients and equalized to non-AA patients over the first 7 days (0.46% vs 0.45%, p=0.8 Table 1). Cellular rejection did not differ by race (HR [CI]=1.4 [0.62,3.2], p=0.4). However AA were at higher risk of antibody mediated rejection (HR [CI]=3.8 [1.3,10.9], p=0.01). African American patients had increased cf-DNA values in the first week following heart transplant. This may be a marker of early injury contributing to increased rates of allograft rejection in AA patients. Further analysis adjusting for confounding variables and determining predictors of clinical outcomes will be included at the time of presentation once follow-up of the GRAFT registry is complete.