Transmission of Anellovirus From Kidney‐Donor to Pediatric Recipient: An Exploratory Study

Background Among the most abundant viruses in the human blood virome are anelloviruses, including alpha ‐, beta ‐, and gammatorqueviruses (TTV, TTMV, and TTMDV). Whether anelloviruses are transmitted through kidney transplantation at a young age and subsequently persist in their new host is unknown. This study investigates the dynamics and composition of the anellome in the blood of six pediatric donor–recipient pairs, with monitoring beginning before transplantation and continuing until 2 years after transplantation. Methods Donors were sampled once, before donation, while recipients were sampled before and multiple times after transplantation (median 6.5 samples). Quantitative PCR, rolling circle amplification, Illumina sequencing, and SCANellome V2 analysis were used to detect, characterize, and compare anellovirus presence in donors and recipients. Results At baseline, four out of six donors tested positive for TTV by quantitative anellovirus PCR, three of whom had sufficient viral loads to enable genomic comparison with their recipients. All recipients tested positive at baseline, five had a moderate viral load (< 10 5 copies/mL), and one had > 10 9 copies of TTV DNA/mL. This recipient was already immunosuppressed before transplantation, and only in this recipient was a donor‐derived anellovirus identified. This lineage was detected among 15 other lineages in the recipient and matched one of the four lineages identified in the donor. Conclusion This finding demonstrates that anellovirus transmission from donor to recipient occurs in pediatric kidney transplantation. This may be associated with pre‐existing immunosuppression.