High prevalence of TT virus infection in French blood donors revealed by the use of three PCR systems

BACKGROUND: The purpose of this study was to determine the prevalence of TT virus (TTV) infection in voluntary blood donors in Southeastern France. STUDY DESIGN AND METHODS: The sera of 289 blood donors were tested for the presence of TTV DNA by two PCR systems detecting genes located in the 5' UTR (primer set A [Set A]) and the open reading frame (ORF2) (primer set B [Set B]) of the viral genome. A randomized sample of 40 blood donors was also tested by a nested-PCR system in the ORF1 by use of primer set C (Set C). Donors were questioned for possible risk factors for virus transmission. RESULTS: In the entire population studied, 30.8 percent of blood donors tested positive with both Sets A and B, and 70.6 percent with at least one set. In the sample tested with three sets of primers, 27.5 percent of blood donors were positive in testing with all PCR systems and 80 percent with at least one system. The specificity of TTV DNA amplification was confirmed by sequencing 10 PCR products obtained with each set of primers. Statistical analysis revealed that the prevalence of TTV reactivity increased with age. CONCLUSION: The high prevalence of TTV reactivity and the absence of a pathologic condition or risk factors obviously associated with the infection in blood donors suggest that there is no need for systematic detection of TN infection before blood donation. Further studies are required to determine if TTV isolates can be responsible for a pathologic condition in humans after blood transfusion.