Early kinetics of Torque Teno virus DNA load and BK polyomavirus viremia after kidney transplantation

Abstract

Although caution should be exerted when interpreting the above findings due to the single-center design of our study and the absence of cases of biopsy-proven BKPyVAN, the present experience would preliminarily suggest that early post-transplant TTV kinetics may inform about the individual risk of BKPyV viremia in KT recipients. Regular monitoring of TTV DNA levels would serve as a comprehensive surrogate for post-transplant immunocompetence and the associated susceptibility to other iRAEs, thus offering practical advantages over the sole assessment of BKPyV replication. 4 Moreover, the feasibility of such an approach is supported by the recent advent of commercial real-time PCR assays targeting a highly conserved segment (5′ untranslated region) of the viral genome, with the potential for a rapid turnaround time. 6 Our research must be considered as hypothesis-generating, and external validation studies on larger mul-

Viruses, friends, and foes: The case of Torque Teno Virus and the net state of immunosuppression

“…84 Therefore, increasing research has been performed to explore the predictive value of blood TTV load for the specific outcome of BKPyV viremia, with mixed results. 54,55,76,85 A positive correlation between the amount of TTV and BKPyV replication was observed in a small French study (66 KT recipients), in which each 0.2 log 10 increases in the TTV DNA level was associated with a 1.50 log 10 increase in BKPyV load. In addition, patients with BKPyV viremia showed higher TTV loads at post-transplant month 6 as compared to non-viremic patients.…”

“…A key role has been identified for BKPyV‐specific T‐cell‐mediated and, to a lesser extent, antibody responses to prevent uncontrolled viral replication and cytopathic damage of the renal tubule epithelium 84 . Therefore, increasing research has been performed to explore the predictive value of blood TTV load for the specific outcome of BKPyV viremia, with mixed results 54,55,76,85 …”

“…By using a larger cohort, our group found that plasma TTV DNA load at month 1 was significantly higher in patients developing BKPyV viremia thereafter (auROC of 0.749). We established at 5.01 log 10 copies/ml the optimal threshold to predict BKPyV viremia, with sensitivity and specificity values of 76.9% and 74.7%, respectively 85 . Accurate risk stratification as soon as the first month after transplantation would allow to focus BKPyV monitoring efforts on a subgroup of highly susceptible recipients, which would benefit from a more rapid tapering of immunosuppression or conversion to mTOR inhibitor even before the development of the first episode of viremia.…”

Monitoring of Torque Teno virus DNAemia in critically ill COVID-19 patients: May it help to predict clinical outcomes?

“…Superinfection events occur frequently in critically ill COVID-19 patients and notably worsen their prognosis [ 26 , 27 ]. Monitoring of TTV DNAemia has been shown to be a useful tool to anticipate the occurrente of a variety of infectious events in SOT and allo-HSCT settings [ [8] , [9] , [10] , [30] , [31] , [32] , [33] ]. Our data suggested that this might also be the case in critically ill COVID-19 patients regarding nosocomial bloodstream infections and VAP.…”

Torque teno virus load predicts allograft rejection but not viral infection after kidney transplantation

“…However, some studies did show an association between TTV load-increase and infectious complications. This discrepancy may be due to differences in study population, start and duration of follow-up, pathogens studied and/or modelling method 45-47 .…”