Kidney Week

Abstract: TH-PO0958

Torque Teno Virus Loads in Pediatric Kidney Transplantation: Insights into Viral Load, Immunosuppression, Human Leukocyte Antigen (HLA) Mismatch, and Age Effect

Session Information

• Transplantation: Clinical - Glomerular Diseases, Infections, and Rejection
  November 06, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Transplantation

• 2102 Transplantation: Clinical

Authors

• Klomp, Luna Shane, Emma Kinderziekenhuis Amsterdam UMC, Amsterdam, NH, Netherlands

Luna Shane Klomp

• Burggraaff, Maarten G. J. M., Amsterdam UMC Locatie AMC, Amsterdam, NH, Netherlands

Maarten G. J. M. Burggraaff

• van der Hoek, Lia, Amsterdam UMC Locatie AMC, Amsterdam, NH, Netherlands

Lia van der Hoek, MSc, PhD

• Feltkamp, Mariet, Sanquin Bloedvoorziening, Amsterdam, NH, Netherlands

Mariet Feltkamp

• Bouts, Antonia, Emma Kinderziekenhuis Amsterdam UMC, Amsterdam, NH, Netherlands

Antonia Bouts, MD, PhD

Background

Kidney transplantation (KTx) is the treatment of choice for children with end-stage renal disease. Lifelong immunosuppression prevents rejection, yet is challenging to balance. Current dosing based on plasma drug levels poorly reflects individual immune status, risking immunosuppressive imbalance. Improved immune biomarkers are needed for better personalized treatment. In adult KTx recipients, higher plasma levels of Torque Teno virus (TTV) may indicate reduced immune function, suggesting TTV as a potential marker for immune activity. Therefore, we aim to investigate the relation between post-transplant TTV load and immunosuppressive drug regimens in pediatric KTx recipients. We hypothesize that TTV load increases after transplantation, and is associated with patient age, immunosuppressive regimen, and HLA-mismatch.

Methods

This cohort study included children with kidney disease, with (n=94, median age=10.5) and without KTx (n=29, median age=11.0). DNA extracted from serum or plasma samples were analyzed with qPCR. KTx samples were collected just before transplantation and up to two years after transplantation (1^styear, every 2 months and 2^ndyear, every 4 months), while control samples were taken only once. Results were analyzed with R-studio.

Results

All patients tested positive for TTV. Before KTx, the median TTV load was 3.39Log₁₀. A peak was observed 4 months post KTx (median:7.72Log₁₀copies/mL;IQR:7.20-8.15Log₁₀copies/mL), which stabilizes to 5.90Log₁₀ after 14 months (IQR=4.51-7.19Log₁₀). Patients without KTx showed a median TTV load of 4.90Log₁₀. No correlation was found between age and TTV load (p=0.64). TTV load significantly decreased over time post-KTx (p=0.002). Immunosuppression regimen (early vs. non-early steroid withdrawal) had no significant effect (p=0.45). TTV load was significantly higher in groups with more HLA mismatches (2-4 vs. 0-2, p<0.01; 0-2, 4-6, p<0.001 and 2-4, 4-6, p<0.05).

Conclusion

In conclusion, post-KTx TTV loads increased considerably, peaking at 4 months, followed by a decrease and stabilization at 14 months. No correlation with age or immunosuppressive regimen was found. However, significant differences in TTV load between the HLA mismatch groups was observed. Future studies will include correlation between TTV loads and levels of immunosuppression.

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.2025x36s52z3