TT virus infection in French hemodialysis patients: Study of prevalence and risk factors

The TT virus (TTV) is a recently discovered DNA virus which was first ident ified in patients with non-A to -G hepatitis following blood transfusion. I n this study, we tested 150 attendees of two hemodialysis (HD) units of the public hospitals of Marseilles, France, for the presence of TTV genome by using a PCR-based methodology. The overall prevalence of TTV viremia was 28 % (compared to 5.3% in blood donors from the same region). We demonstrated the existence of chronic infections and superinfections by strains belongin g to different genotypes, The prevalence of infection was higher in patient s originating from Africa, in patients with previous blood transfusion or o rgan transplantation, in patients with antibody to hepatitis B core antigen , and in those with diabetes mellitus. A high prevalence of TTV infection ( 50%) was also observed in a population of patients with diabetes mellitus b ut without renal disease. No significant relationship was found between TTV viremia and hepatitis C virus or GB virus C, transaminases, age, sex, and duration of HD treatment. The PCR amplification products (located in open r eading frame 1 of the TTV genome) were sequenced. These genomic sequences w ere submitted to phylogenetic analysis by using the Jukes-Cantor algorithm for distance determination and the neighbor-joining method for tree buildin g. In several instances, sequences from viruses isolated in a HD unit mere grouped in the same phylogenetic cluster, These results together,vith the d ifferent distribution of cases in the two HD units suggest there is viral t ransmission within each.