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[Demonstration of TT virus in liver tissue fixed in formalin and embedded in paraffin]
M P Foschini1, L Morandi, S Macchia
1Sezione di Anatomia Patologica, Istologia e Citologia Patologica M. Malpighi, Dipartimento di Oncologia, Ospedale Bellaria, Via Altura 3, I-40139 Bologna. mariapia.foschini@ausl.bologna.it
Introduction:
TT virus has been recently isolated in Japan in patients with acute and chronic non-A/non-G hepatitis. Its possible etiopathogenetic role in causing hepatitis has been initially taken in consideration. On the contrary, more recent studies deny the importance of TT virus in causing liver damage. Most of the studies are based on serological data or on viral detection from frozen liver tissue.
Aim Of The Study:
In the present paper we describe a method to detect viral genome from formalin-fixed and paraffin-embedded liver tissue.
Materials And Methods:
Twelve needle biopsies from liver were studied. Six cases were selected on the basis of serological negativity for HBV and HCV markers. Five cases of HCV-related chronic hepatitis and one HCV- and HIV-positive intravenous drug abuser were also included. All patients underwent liver biopsy, performed with a 14-G needle. Liver specimens were formalin-fixed and paraffin-embedded as routine. From each block, sections were cut and stained for histopathologic examination. Additional 5 microns sections were employed to extract DNA for nested PCR.
Results:
In 2 of 12 cases studied, TT virus genome was found. In both cases the presence of viral DNA was confirmed by sequencing. Both patients were male. The first patient was a 39-year-old HIV- and HCV-positive intravenous drug abuser. The second patient was a 60-year-old heavy alcohol drinker. In both cases the presence of TT virus apparently did not affect the histological picture.
Conclusion:
It is possible to detect TT virus genome from formalin-fixed and paraffin-embedded tissue. This method offers the possibility to perform retrospective studies.