[Pathogenecity and replication of transfusion transmitted virus in liver tissue by in situ hybridization]

To study its pathogenecity based on infection status and replication of transfusion transmitted virus (TTV) in the liver tissues.

Using recombinant plasmid as template and symmetrical and asymmetrical polymerase chain reaction (PCR), double-strand and single-strand TTV probes were labeled with digoxigenin. Fifty-six cases of liver biopsy specimens were detected by in situ hybridization, and six positive cases of them were tested further with single-strand probes.

TTV DNA was found in 14 of 51 patients with non A and non G hepatitis (27.5%), and five cases in the control group were negative. TTV DNA was mainly observed in the nuclei of hepatocytes and pathologic changes and necrosis in the infected liver cells were not so apparent, but they could be seen in the liver tissues of acute, chronic and severe hepatitis, as well as of liver cirrhosis. TTV genome strand hybridization detected by single-strand probe was consistent with that by double-strand probe. Both TTV genome strand and its complementary strand were present in the two cases of liver specimens, but hybridizational signals were weaker in the latter than those in the former.

TTV could cause injury and replicate itself in the liver, but no obvious and direct injury to hepatocytes.