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Abstract: FR-PO780

Non-Invasive Monitoring With Torque Teno Virus for the Prediction of Antibody-Mediated Rejection in Kidney Transplant Patients

Session Information

Category: Transplantation

  • 2002 Transplantation: Clinical

Authors

  • Van Hummelen, Paul, Natera, Inc., Austin, Texas, United States
  • Tang, Jessica, Natera, Inc., Austin, Texas, United States
  • Kumar, Dhiren, Virginia Commonwealth University, Richmond, Virginia, United States
  • Mcdougan, Felecia, Virginia Commonwealth University, Richmond, Virginia, United States
  • Yashroy, Kannagi, Natera, Inc., Austin, Texas, United States
  • Ahmed, Ebad, Natera, Inc., Austin, Texas, United States
  • Prewett, Adam, Natera, Inc., Austin, Texas, United States
  • Heilek, Gabrielle, Natera, Inc., Austin, Texas, United States
  • Tabriziani, Hossein, Natera, Inc., Austin, Texas, United States
  • Gauthier, Phil, Natera, Inc., Austin, Texas, United States
  • Gupta, Gaurav, Virginia Commonwealth University, Richmond, Virginia, United States
Background

Kidney transplant (KT) patients require immunosuppressive (IS) treatment to prevent allograft rejection. The final net state of IS is a result of preexisting comorbidities, induction therapy and maintenance regimens. Torque Teno Virus (TTV) has been reported to be a marker of immune function and transplant-related complications in immunocompromised patients. TTV is a prevalent, non-pathogenic single-strand DNA virus that is easily detected in blood. Evidence for the clinical benefit of quantitative TTV monitoring in KT recipients is still emerging.

Methods

We selected 245 longitudinal serum samples from 66 KT patients with: a) stable without rejection in 1st year of transplant [N=26]; b) BK Polyoma viremia/nephropathy [N=10]; c) T-cell mediated Rejection (TCMR) [N=7]; and d) Antibody-mediated Rejection (AMR) [N=23]. Samples were obtained within days of transplantation surgery (Tx), pre-diagnosis, at biopsy diagnosis and several weeks after diagnosis. TTV levels were quantified by real-time quantitative PCR.

Results

At Tx, TTV levels were between 103-105 cps/ml and increased to 1010 in the first three months, followed by a gradual decrease to around 106 cps/ml. TTV levels varied by 2 logs between patients within each diagnosis group, confirming earlier published results, while the kinetics within each patient was more consistent. A delayed TTV increase in the first 3 months was observed in AMR patients, with overall lower TTV levels, while TCMR patients had higher and steady TTV levels. Patients with BK viremia/nephropathy generally had the highest titers, suggesting more robust IS.

Conclusion

Lower TTV titers in patients who were diagnosed with AMR may indicate an active immune state, possibly due to poor IS response. In contrast, BK viremia may be associated with high immune suppression and high TTV titers. More studies and patients are needed to confirm these results.

Funding

  • Commercial Support