Torque Teno Virus is associated with the state of immune suppression early after liver transplantation.

The development of non-invasive biomarkers that reflect the state of immune suppression remains an unmet need in liver transplantation (LT). Torque Teno Virus (TTV) is a highly prevalent, non-pathogenic DNA virus whose plasma levels may be associated with the immune status of the host. The aim of this study was to assess the role of TTV as a biomarker of immune suppression in LT recipients. TTV DNA in plasma was quantified by real-time PCR at different time-points during the first year after transplant in a prospectively followed cohort of 63 de novo LT recipients, and any correlation between TTV DNA and biopsy-proven acute cellular rejection (ACR) and opportunistic infections was then evaluated. In addition, TTV DNA was studied in 10 long-term LT recipients in monotherapy with tacrolimus, 10 tolerant recipients and 10 healthy controls. TTV was detected in the plasma of all patients. Among the 63 LT recipients, 20 episodes of ACR were diagnosed, and there were 28 opportunistic infections, 26 of them cytomegalovirus infections. TTV viremia was significantly lower during ACR (5.95 vs 4.41 log10 copies/ml, p=0.002) and significantly higher during cytomegalovirus infections (5.79 vs 6.59 log10 copies/ml, p=0.009). The area under the ROC curve of TTV viral load for the diagnosis of moderate ACR was 0.869, with a sensitivity and negative predictive value of 100%, respectively, for a cutoff point of 4.75 log10 copies/ml. There were no statistically significant differences in TTV DNA in either long-term or tolerant patients and healthy controls CONCLUSION: Plasma TTV DNA levels are associated with immune-related events after LT and could constitute a potential biomarker of the state of immune suppression during the first months after transplant. This article is protected by copyright. All rights reserved.