Hepatitis cRNA quasispecies complexity in patients with alcoholic liver disease

Abstract

Alcohol abuse is described as a major cofactor in the development of hepatitis C (HCV) associated liver disease and may play a role in the outcome of interferon-based treatment interventions. The association between HCV viral heterogeneity and alcohol has not been previously described. This study was designed to evaluate the quasispecies nature of the HCV population in patients with compensated and decompensated alcoholic liver disease, to test the hypothesis that alcoholics have greater complexity than matched nonalcoholic controls. A nonisotopic heteroduplex complexity assay (HCA) was first validated by comparison with results of quasispecies complexity determined by subcloning and sequencing of amplicon products from the E2/NS1 hypervariable coding region (HVR). Subsequently Hepatitis C virus (HCV) infection represents an important comorbidity in patients with alcohol abuse and alcoholic liver disease. Seroprevalence surveys have established that 8% to 45% of this cohort may have concomitant HCV antibodies suggestive of active, ongoing infection. 1 The combination of alcohol and HCV has been epidemiologically associated with increased risk of liver disease injury and progression. [2][3][4] Furthermore, there are limited data that suggest that interferon treatment response is also blunted in these patients. 5 The underlying pathophysiology that explains these differences has not yet been elucidated.Factors that may influence disease progression and treatment outcome include virus characteristics and host response. We have previously studied genotype distribution in patients with alcoholic liver disease and did not discern significant variation from nonalcoholic patients. Using a serologic method to assign genotypes, we did observe an increased percentage of untypeable viral isolates, which may be attributable to an altered immune response against type specific epitopes. 6 This observation raised the possibility that altered immunosurveillance might play a role in impaired viral clearance and might permit the development of a population of closely related variants.HCV is an RNA virus that lacks the ability to perform editing and correction in replication products. Therefore, it is capable of generating multiple mutant forms within an individual patient. These variants have been termed quasispecies. The envelope coding domain contains a hypervariable region that is most likely to show inefficient clearance of emerging quasispecies, though mutant emergence and selection may be seen in other coding domains as well. We hypothesized that quasispecies complexity may be increased in alcoholic patients compared with a nonalcoholic control group based on clinical observations of outcomes and interferon response rates. A rapid semiquantitative methodology to assess quasispecies complexity was developed and validated, and the hypothesis was tested in alcoholic patients and a matched control cohort. PATIENTS AND METHODS PatientsThe study cohort consisted of 20 patients with alcoholic liver disease and concomitant HCV infec...

HCV quasispecies evolution: association with progression to end-stage liver disease in hemophiliacs infected with HCV or HCV/HIV

“…HCV quasispecies complexity and diversity have been examined in relation to HIV-related immunosuppression, [29][30][31] patient response to interferon-based treatment, 8,[32][33][34][35][36][37] response to liver transplantation, 9,38-41 and in patients with alcoholism 18,42 or hemophilia. 43 These studies have generated conflicting results.…”

“…Amplification of the E2/NS1 was carried out using a nested reverse transcription-polymerase chain reaction (RT-PCR) method described by Sherman et al 18 The first set of primers used were: external forward (EF), position 1048 to 1067, 5Ј-GGTGCTCACTGGGGAGTCCT-3Ј; external reverse (ER), position 1291c to 1269c, 5Ј-CATTGCAGT-TCAGGGCCGTGCTA-3Ј; internal forward (IF), position 1087 to 1106, 5Ј-TCCATGGTGGGGAACTGGGC-3Ј; and internal reverse (IR), position 1262c to 1243c, 5Ј-TGCCAACTGCCGTTGGTGTT-3Ј, with the primer positions corresponding to the HCV sequence described by Choo et al 19,20 These primers flank a 136-bp region of the E1/E2 envelope-coding domain that includes the HVR1. The second set of primers, used to amplify a 1270-bp product that includes the HCV core protein, were: EF, position Ϫ62 to Ϫ42, 5Ј-CTTGTGGTACTGCCTGATAGG-3Ј; ER position 1291c to 1269c, 5Ј-CATTGCAGTTCAGGGCCGTGCTA-3Ј; IF, position Ϫ51 to Ϫ29, 5Ј-GCCTGATAGGGTGCTTGCGAGTG-3Ј, and IR, position 1262c to 1243c, 5Ј-TGCCAACTGCCGTTGGTGTT-3Ј.…”

The clinical and physiological spectrum of interferon-alpha induced thyroiditis: Toward a new classification

“…71 HCV quasispecies have been shown to be associated with certain HCV disease phenotypes, 72,73 and with response to IFN␣ therapy. 74 Therefore, it was possible that viral genotype may influence the susceptibility to develop IIT.…”

New Insights Into the Relationships Among Alcohol Consumption, Hepatocellular Carcinoma and Hepatitis C Virus Infection

“…8) HCV quasispecies complexity, in the hyper-variable regions, is enhanced under the influence of alcohol. This result was reported in a study by Takahashi et al The mean polymerase chain reaction polymorphism, related to hyper-variable regions, was higher in patients consuming alcohol, compared to the ones who abstain (45,46). 9) Alcohol impairs cell-mediated immunity by the inhibition of DCs, which results in hindering the immune system to overcome HCV infection (44).…”