Presence of hepatitis C Virus DNA sequences in the DNA of infected patients

Background: Hepatitis C virus (HCV) consists of a single positive RNA molecule. In the present study we investigated the possibility that HCV may undergo integration into the genomic DNA of infected cells. Materials and methods: HCV(+) patients (n = 51) and 21 HCV(-) controls were investigated for HCV integration. RNase treated DNA samples of mononuclear cells (MNC) and liver biopsies of the patients were screened by PCR and seminested PCR processes for detection of integration. Positive results were further investigated by means of Southern analysis of patient's DNA as well as sequencing of PCR products of patient's DNA. Results: Positive PCR results were detected in 4/51 of the HCV(+) patients and in none of the control group. Southern analysis showed the presence of HCV sequence in a 23 kbp band of the patient which is much larger than the viral genome itself (9.646 kbp). Sequencing of cloned PCR products showed an identity of over 95.0% to HCV. Conclusions: As much as we are aware this is the first demonstration of the possible integration of HCV sequences into the DNA of HCV(+) patients.