Aim: Organ transplantation is the preferred treatment for terminal organ failures like end-stage renal, liver and heart diseases. The need for surveillance of allograft’s health is crucial for long term survival. The current study aimed at demonstrating the clinical performance of ddcfDNA as a biomarker (TrunomeTM Assay) in detecting any events of rejection earlier compared to the gold standard biopsy in liver transplant recipients.
Methods: Around 5 ml and 2 ml of peripheral blood was collected from adult and pediatric liver transplant recipients respectively. Serial monitoring of the patients was done on the indicated post operative days (POD 3, 7, 14 and 30). Additional blood samples were collected before the biopsy for patients with suspicion of rejection/infection. The absolute quantification values of ddcfDNA and its percentage were derived with Proprietary Patented Trunome Protocol using a proprietary patented set of SNPs along with granzyme-B levels. A comparative analysis was performed between ddcfDNA levels and biopsy results. Mann Whitney was used to compare continuous variables and Chi-square test was performed to compare categorical variables, a two-sided p-value < 0.05 was defined as significant.
Results: A total of 108 subjects (59 adults; 49 pediatric) were recruited for the study out of which 15 subjects (9 adults; 6 pediatric) were excluded for various reasons. DdcfDNA and granzyme B levels were derived and compared with the biopsy results for both adult and pediatric groups separately. Percentage ddcfDNA levels were significantly elevated in the rejection group (n=24) as compared to the non-rejection group (n=69), in both adult and pediatric groups (median %ddcfDNA levels in adult group 9.02% (n=15) vs 3.99% (n=35); p<0.0001 and in pediatric group 8.29% (n=9) vs 1.41% (n=34); p<0.0001). AUC-ROC analysis revealed that the %ddcfDNA levels can predict graft health precisely in both adult (AUC- 0.87; p<0.0001) and pediatric groups (AUC- 0.95; p<0.0001). Moreover, %ddcfDNA levels (with a threshold >10% in adult group and >8% in pediatric group) was able to predict rejection events with 91.67% sensitivity, 95.65% specificity, 88.0% positive predictive value, 97.06% negative predictive value and 94.62% accuracy. Moreover, ddcfDNA levels along with granzyme B levels were also able to distinguish between rejection events and infections.
Conclusion: In this study, we demonstrate the effectiveness and diagnostic potential of ddcfDNA levels in predicting rejection events and distinguishing them from infections, suggesting its potential as a standard diagnostic tool.