BACKGROUND/AIMS: Contradictory data have been reported about the predictive value of the variability in interferon sensitivity determining region (ISDR) of hepatitis C virus (HCV) genotype-1b on response to interferon-alpha (IFN-alpha) therapy. The aim of this study was to examine this issue in a series of patients with long-term response to IFN treatment. METHODS: We retrospectively analyzed 24 patients with chronic HCV genotype-1b infection treated with IFN-alpha (total dose median 677, range 216-1350 MU) selected in 6 Italian Liver Units. These patients were defined as true long-term responders (LTR) since they showed persisting biochemical and virological responses to IFN treatment (mean follow-up 38 months). HCV genomes from pretreatment serum samples were amplified and directly sequenced. The ISDR amino-acid sequences obtained were aligned and compared with the published sequence of HCV-J. RESULTS: Amino-acid substitutions were found in 23 of the 24 patients, and 22 of them showed an H to R amino-acid change at codon 2218. Fourteen patients showed only one mutation (at codon 2218), two had 2, five had 3, one had 4 and one had 5 mutations. When we compared the ISDR sequences from the 24 LTR with those of non-responders (NR), we found no significant correlation between the number of mutations and the response to therapy. CONCLUSIONS: Our results demonstrate that the persisting efficacy of IFN treatment in patients with chronic HCV is not related to the number of ISDR amino acid substitutions of the infecting viruses. Further studies are needed to verify whether other NS5A sequences outside the ISDR might be involved in the mechanisms of IFN resistance.
BACKGROUND/AIMS: Contradictory data have been reported about the predictive value of the variability in interferon sensitivity determining region (ISDR) of hepatitis C virus (HCV) genotype-1b on response to interferon-alpha (IFN-alpha) therapy. The aim of this study was to examine this issue in a series of patients with long-term response to IFN treatment. METHODS: We retrospectively analyzed 24 patients with chronic HCV genotype-1b infection treated with IFN-alpha (total dose median 677, range 216-1350 MU) selected in 6 Italian Liver Units. These patients were defined as true long-term responders (LTR) since they showed persisting biochemical and virological responses to IFN treatment (mean follow-up 38 months). HCV genomes from pretreatment serum samples were amplified and directly sequenced. The ISDR amino-acid sequences obtained were aligned and compared with the published sequence of HCV-J. RESULTS: Amino-acid substitutions were found in 23 of the 24 patients, and 22 of them showed an H to R amino-acid change at codon 2218. Fourteen patients showed only one mutation (at codon 2218), two had 2, five had 3, one had 4 and one had 5 mutations. When we compared the ISDR sequences from the 24 LTR with those of non-responders (NR), we found no significant correlation between the number of mutations and the response to therapy. CONCLUSIONS: Our results demonstrate that the persisting efficacy of IFN treatment in patients with chronic HCV is not related to the number of ISDR amino acid substitutions of the infecting viruses. Further studies are needed to verify whether other NS5A sequences outside the ISDR might be involved in the mechanisms of IFN resistance.
Authors: Joonho Yoon; Jong In Lee; Soon Koo Baik; Kwang Ho Lee; Joon Hyung Sohn; Hyean Woo Lee; Jun Namkung; Sei Jin Chang; Jong Whan Choi; Hyun Won Kim; Byung-Il Yeh Journal: World J Gastroenterol Date: 2007-12-14 Impact factor: 5.742
Authors: Thomas Kuntzen; Andrew Berical; Jean Ndjomou; Phil Bennett; Arne Schneidewind; Niall Lennon; Bruce W Birren; Carla Kuiken; Matthew R Henn; Peter Simmonds; Todd M Allen Journal: J Med Virol Date: 2008-08 Impact factor: 2.327
Authors: S J Polyak; K S Khabar; D M Paschal; H J Ezelle; G Duverlie; G N Barber; D E Levy; N Mukaida; D R Gretch Journal: J Virol Date: 2001-07 Impact factor: 5.103
Authors: Cíntia Bittar; Ana Carolina G Jardim; Lilian H T Yamasaki; Artur T L de Queiróz; Claudia M A Carareto; João Renato R Pinho; Isabel Maria V G de Carvalho-Mello; Paula Rahal Journal: BMC Infect Dis Date: 2010-02-23 Impact factor: 3.090