TT virus infection in acute and chronic liver diseases and in patients regularly receiving blood products in Belgium

Background: TT viruses are single-stranded DNA viruses, suggested to be involved in non A-E hepatitis. We studied the prevalence of TTV infection in acute or chronic hepatitis in Belgium in comparison with that in blood donors and in patients regularly receiving blood products. Methods : TTV-DNA was detected by PCR using the primer set of Takahashi et al (1998) or a nested-PCR specific for genotype-2, because it had been reported that this subtype might be more pathogenic (Tagger et al.1999). Results : TTV-DNA was present in 49% of 128 patients with chronic hepatitis C, in 54% of 54 with chronic hepatitis B and in 54% of 24 with acute liver failure. This prevalence is similar to the 47% in 127 patients with clotting disorders, or the 64% in 103 undergoing chronic haemodialysis, but lower than the 29.7% found in 340 healthy blood donors. Significant differences in clinical or biochemical characteristics between TTV- positive or TTV-negative patients could not be substantiated. The genotype-2 subgroup comprised 3.9%, but they also did not differ from non genotype-2 patients. Conclusions : The prevalence of TTV infection was higher in patients than in healthy blood donors. Its clinical significance remains questionable since clinical and biochemical characteris- tics were not different between TTV positive and TTV negative patients. The higher prevalence of TTV in patients might be related to parenteral transmission, but the relatively high preva- lence in healthy blood donors points to an additional presumably faeco-oral infection. The presence of TTV in animals suggests that infection might also originate from food. Long term follow-up will have to define whether co-infection with TTV eventually alters the natural history of chronic hepatitis. (Acta gastroenterol. belg., 2004, 67, 161-165).