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Genetic heterogeneity is a characteristic feature of hepatitis C virus (HCV) and it reflects selection mechanisms affecting the virus. It is considered a major factor contributing the viral persistence and drug resistance. The following work presents the preliminary results of 5'UTR and E2/HVR1 genetic variation analysis and comparison in serum and peripheral blood mononuclear cells (PBMC) of 7 patients before and during the early phase of pegylated interferon alfa (PEG-IFN-alpha) and ribavirin therapy. Single strand conformational polymorphism (SSCP) analysis revealed genetic stability of 5'UTR in all but one patient who did not respond to treatment (SVR-), where new genetic variants appeared. E2/HVR1 genetic changes were characteristic in patients displaying treatment failure (SVR-) and usually reflected fluctuations in complexity and appearance of new genetic HCV variants. Genetic changes (reduction in complexity) were found in one of three sustained virological responders (SVR+ patients). Comparatory analysis of the HCV quasispecies present in serum and PBMC showed differences in at least one analysed region in all non-responders. Presented results suggest the independent forces driving genetic changes in analysed regions. They also point out the presence of genetic compartmentalization possibly having an impact on antiviral treatment result.

Unlabelled: The aim of the study was to evaluate the presence of HCV replication in bone marrow cells derived from patients displaying hematological disorders. We analysed serum, peripheral blood mononuclear cells (PBMC) and bone marrow samples obtained from 27 patients displaying the following dysfunctions: lymphoma, trombocytopenia, haemophilia, pancytopenia and acute myeloid leukemia (AML). The presence of HCV-RNA in samples was detected by RT-PCR. All the serum samples were HCV-RNA positive as well as 9 out of 27 (33%) PBMC and 17 out of 27 (63%) of bone marrow samples. Independently to the disorder type, the co-presence of HCV-RNA in serum and bone marrow with the simultaneous absence of the viral genetic material in PBMC was detected in 5 (18.5%) of patients. This result suggests that bone marrow is a site of active viral replication. To check whether a viral replication generates any mutations, an SSCP analysis of the 5'UTR viral region was performed. The difference in the viral sequence derived from serum, PBMC and bone marrow was detected in one case. This result may indicate the occurrence of mutation process during the viral replication in bone marrow. An immunohistochemical analysis of bone marrow smears showed the presence of HCV antigens., Conclusion: bone marrow cells of patients displaying hematological disorders represent a putative site of extrahepatic HCV replication.

Our aim was to discuss the practical value of HBV DNA polymerase (DNAp) determination. DNAp activity is a good marker of HBV high replication in patients with chronic hepatitis B (HBeAg+), very useful during monitoring of immunostimulation and/or antiviral treatment.