TT virus infection in healthy children and in children with chronic hepatitis B or C.

Abstract

The existence of a novel human virus, designated TT virus (TTV), has been reported in association with acute and chronic liver disease of unknown cause. To evaluate the prevalence and clinical significance of TTV infection in childhood. Sera from 104 healthy children, 85 patients with chronic hepatitis B (HBV) and 29 with chronic hepatitis C (HCV), were tested by polymerase chain reaction with primers corresponding to conserved regions within a part of ORF 2. To characterize polymerase chain reaction products, TTV isolates from 15 subjects were directly sequenced. TTV DNA was detected in 22 (21%) of 104 healthy children and in 55 (65%) of 85 and 20 (69%) of 29 HBV- and HCV-infected individuals, respectively. No significant difference was observed in aminotransferase levels of HBV- or HCV-infected patients with or without TTV coinfection. Sequence analysis showed a high degree of genetic heterogeneity between TTV isolates. A striking difference was found in the prevalence of TTV between healthy children and patients with chronic HBV or HCV infection (P <.0005). However, based on these results, TTV alone or as coinfection does not seem to cause or exacerbate liver damage in childhood.