Arch Virol (2004) 149: 1423–1433 DOI 10.1007/s00705-004-0320-0 Molecular characterisation of SENV and TTV infections in hepatopathic liver-transplant patients Brief Report D. Genovese 1 , S. Dettori 1 , C. Argentini 1 , L. A. Kondili 1 , V. La Sorsa 1 , G. Tisone 2 , M. Angelico 3 , and M. Rapicetta 1 1 Laboratory of Virology, Istituto Superiore di Sanit` a, Rome, Italy 2 Liver Transplant Center, “Tor Vergata” University, Rome, Italy 3 Gastroenterology Unit, Department of Public Health, “Tor Vergata” University, Rome, Italy Received October 7, 2003; accepted February 12, 2004 Published online April 5, 2004 c  Springer-Verlag 2004 Summary. The presence of SENV and TTV infections among 50 patients who had undergone liver transplantation was evaluated. UTR amplification showed that 46 (92%) sera were positive. ORF-1 amplification showed that 25 (50%) patients were positive for either SENV (51.3%), TTV (10.8%), or both (37.8%) all confirmed by sequencing and phylogenetic analysis. SENV-D and SENV-H were the most prevalent viruses. The phylogenetic analysis of isolates showed that whereas SENV-D and SENV-G viruses showed sequence stability and strain persistence, SENV-H had cleared or mutated. Biological differences seem to exist among different genotypes in terms of viral replication and their persistence. ∗ TTV is a single-stranded DNA virus with a genome of approximately 3.8 kb with negative polarity [11]. In terms of the genomic sequence, TTV, although a DNA virus, shows a great degree of diversity, and different genotypes have been recognized [3, 13]. The virus has been tentatively placed in the new genus Anellovirus [4, 9], which also includes the eight genotypes of SENV, provisionally classified into the group 3 of the new genus [8, 17]. When comparing TTV geno- types to SENV genotypes, the degree of homology of the nucleic acid sequences varies according to the genomic region. The untranslated region (UTR) appears to be well conserved, whereas for the coding region, only 40–60% homology has been observed. The rate of detection of TTV using PCR greatly depends on the primers chosen. The first PCR assays to be applied for TTV, which made