Hepatitis: Takkenberg RB

Takkenberg RB, Zaaijer HL, ten Cate DF, Biemond BJ, Jansen PL, Reesink HW. · Academisch Medisch Centrum/Universiteit van Amsterdam. · Ned Tijdschr Geneeskd. · Pubmed #19489299 No free full text.

This publication has no abstract.

Takkenberg RB, Zaaijer HL, Molenkamp R, Menting S, Terpstra V, Weegink CJ, Dijkgraaf MG, Jansen PL, Reesink HW, Beld MG. · AMC Liver Center, Department of Gastroenterology and Hepatology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. · J Med Virol. · Pubmed #19382261 No free full text.

Abstract: Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) serves as a template for viral replication and plays a role in persistence of HBV infection. The origin and significance of cccDNA in plasma however, is not well understood. A sensitive, specific, and reproducible real-time PCR for detection and quantitation of cccDNA in plasma of chronic hepatitis B patients was developed and validated. Four HBV DNA reference panels, and 96 plasma samples of chronic hepatitis B patients were analyzed. Results were compared with total HBV DNA levels, individual ALT levels and the Histology Activity Index (HAI). This cccDNA assay had a lower limit of detection at 15 copies/PCR, a lower limit of quantitation at 91 copies/PCR and a correlation coefficient (R) of 0.98 (P < 0.0001). cccDNA was detected in two of four international panels. Significant correlation was found between cccDNA and total HBV DNA levels in both panels (R = 0.96, and R = 0.43) and in samples of the chronic hepatitis B patients (R = 0.88, P < 0.0001). In 57% of these samples cccDNA was detectable. Mean level of cccDNA was 0.16% of total HBV load. Plasma cccDNA levels were higher in HBeAg positive samples than in HBeAg negative samples (4.91 log copies/ml vs. 3.88 log copies/ml, P < 0.0001). Levels of total HBV DNA and HBV genotype did not influence cccDNA detection. ALT levels and HAI-score were not correlated with plasma cccDNA levels. These findings suggest that cccDNA levels in plasma are not the result of increased hepatocyte degeneration, but indicate that other mechanisms might be responsible.

Zaaijer HL, Takkenberg RB, Weegink CJ, Rebers SP, Menting S, Reesink HW, Schinkel J, Molenkamp R. · Laboratory of Clinical Virology, Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. · J Med Virol. · Pubmed #19152408 No free full text.

Abstract: Serial monotherapy and add-on regimes for treatment of chronic hepatitis B virus (HBV) infection may induce the accumulation of viral resistance mutations in patients, reducing the options for ongoing viral suppression. The induction of antiviral resistance by serial application of polymerase inhibitors does not necessarily imply that the subsequent combined use of the drugs will fail. Some HIV strains resistant to one polymerase inhibitor show increased susceptibility to another polymerase inhibitor. After failure of sequential lamivudine and adefovir monotherapy, two patients with hepatitis B changed to treatment with lamivudine plus adefovir and had renewed suppression of HBV. To study the mutational history of resistant HBV subpopulations in the two patients, a part of the HBV polymerase gene was amplified, cloned, sequenced, and analyzed for the presence of mutations, in sequential plasma samples. In both patients serial monotherapy caused the replacement in all HBV clones of wild-type virus by classical lamivudine resistant mutants (L180M and M204V/I), which were replaced subsequently by adefovir resistant mutants (A181V and N236T). When finally lamivudine was added to adefovir, the A181V adefovir mutation persisted in all clones and lamivudine-related mutations did not reappear. During 18 months of combination therapy, HBV-DNA levels decreased 10,000, respectively, 1,000-fold, despite the earlier resistance to lamivudine and adefovir. Although clinically insufficient, this effect indicates that HBV polymerase resistance mutations may be antagonistic, which is relevant if chronic HBV infection is to be treated by a combination of polymerase inhibitors.