Assessment of prevalence and load of torquetenovirus viraemia in a large cohort of healthy blood donors

OBJECTIVES: Torquetenovirus (TTV) is an emerging marker of functional immune competence with the potential to predict transplant-related adverse events. A large-scale epidemiological study was performed to understand how basal values vary in healthy individuals according to age and gender.; METHODS: We tested plasma from 1017 healthy blood donors aged 18-69years. The presence and load of TTV were determined by a real-time PCR assay. A sub-cohort of 384 donors was tested for anti-cytomegalovirus IgG antibodies, and 100 participants were also tested for TTV viraemia on a paired whole blood sample.; RESULTS: The overall prevalence of TTV was 65% (657/1017) with a mean (±SD) growth of 5±4% every 10years of age increase, but stably higher in males (465/690, 67%) than in females (192/327, 59%). Mean (±SD) TTV load was 2.3±0.7 Log copies/mL with no sex difference. TTV viraemia showed modest increases along 10-year age intervals (mean±SD: 0.3±0.1). TTV viraemia in donors sampled 2years later remained stable (mean±SD: 2.3±0.8 versus 2.2±0.7 Log copies between samples). Twenty-six per cent (9/34) of blood donors with TTV-negative plasma scored positive when whole blood was tested, and the donors with positive plasma showed a mean (±SD) 1.4±0.5 Log increase in copy numbers when whole blood was tested.; CONCLUSIONS: This study establishes the mean value of TTV viraemia in plasma in healthy blood donors and suggests that ageing causes only minimal increases in TTV viraemia. Copyright © 2020 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.