Most of the women with HCV infection 17 years after receiving HCV-contaminated anti-D immune globulin had evidence of slight or moderate hepatic inflammation on liver biopsy, about half had fibrosis, and 2 percent had probable or definite cirrhosis.

The genomic sequences of viruses that are highly mutable and cause chronic infection tend to diverge over time. We report that these changes represent both immune-driven selection and, in the absence of immune pressure, reversion toward an ancestral consensus. Sequence changes in hepatitis C virus (HCV) structural and nonstructural genes were studied in a cohort of women accidentally infected with HCV in a rare common-source outbreak. We compared sequences present in serum obtained 18–22 yr after infection to sequences present in the shared inoculum and found that HCV evolved along a distinct path in each woman. Amino acid substitutions in known epitopes were directed away from consensus in persons having the HLA allele associated with that epitope (immune selection), and toward consensus in those lacking the allele (reversion). These data suggest that vaccines for genetically diverse viruses may be more effective if they represent consensus sequence, rather than a human isolate.

Hepatitis C virus (HCV) infection is the main cause of non-A, non-B hepatitis. 1-5 HCV consists of a heterogeneous mix of isolates defined by genotype, each of which is further classified into subtypes. 6,7 A number of factors have been considered in terms of their potential to predict the outcome of the disease. These include age of infection, viral typesubtype, quasispecies, viral load, and mode of infection. [8][9][10][11][12][13] Clinical heterogeneity in disease progression may reflect viral heterogeneity and variations in host response. 14-17 The human leukocyte antigen (HLA) has been shown to influence host response to infection. [18][19][20][21][22] Although HLA class II genes have shown associations with viral clearance or persistence of the HCV these findings are not uniform. [23][24][25][26][27][28] In addition, direct comparisons between studies is often difficult because of heterogeneity of ethnic background, viral genotype, phenotype frequencies of individual alleles between populations, gender, and duration of disease. To avoid heterogeneity of risk factors and confounding variables in viral type/subtype we studied a unique cohort of individuals all infected by anti-D contaminated from a single source of HCV 1b. The patients were of similar ethnogeographic background and had an absence of competing risk factors for liver disease.The present study is a follow-up investigation of the well-documented series of Irish women who were inadvertently infected with HCV as a result of receiving contaminated anti-D immunoglobulin (from a single source) in 1977 to 1978. [29][30][31] The contaminating HCV 1b was derived from a single infected donor. [30][31][32][33] The homogeneity of this group allows one to examine variation in host response to HCV infection without the potentially confounding influence of factors such as gender, specific HCV genotype, age range, and general health status. The purpose of the present study was to address whether particular HLA class II alleles are associated with clearance or persistence of HCV type 1b. PATIENTS AND METHODSThe study group consisted of 156 female individuals all of whom were iatrogenically infected between May 1977 and November 1978 with HCV type 1b from a single source. All 156 cases tested positive for antibodies to HCV (by recombinant immunoblot assay; Chiron Corporation, Emeryville, CA) and 46% (n ϭ 72) were positive for HCV RNA by qualitative reverse transcriptase-polymerase chain reaction (RT-PCR) using the Roche AMPLICOR test (F. Hoffmann-La Roche Ltd., CH-4070 Basel, Switzerland). The HCV status of the 84 patients who tested negative on initial qualitative HCV RT-PCR screening was confirmed by retesting within an 18-month period. The HCV genotype of the 72 virus-positive individuals was confirmed to be HCV 1b by reverse line probe assay (Inno-Lipa HCV II, INNOGENETICS N.V., Zwijndrecht, Belgium).Investigations were performed with informed consent and complied with a standardized protocol in compliance with standard of care and in accordance hospital eth...

The aim of this study was to investigate the relationship between human leukocyte antigen (HLA) class II genes and the natural fluctuations in hepatitis C viral load in a homogeneous patient population. The study group consisted of 57 viremic (hepatitis C virus [HCV] 1b) women for whom HLA class II DRB1 and DQB1 haplotyping, virologic, histologic, and biochemical markers of disease activity were available. All patients were infected with HCV 1b from the same source of hepatitis C-contaminated anti-D immunoglobulin during the period from May 1977 to November 1978. The mean slope of change of viral load was 0.34 (SD ؎ 0.73) log 10 viral copies/mL/year, which is significantly different from zero, P < 10 ؊9 . Analysis of the relationship between the slope of change of viral load and HLA class II haplotype indicated a significantly different slope of change of viral load between the alleles of (1) DRB1*15 and DRB1*0701, and (2) DQB1*0602 and DQB1*0201, P c ‫؍‬ .036 and P c ‫؍‬ .026 after Bonferroni correction for multiple comparisons, respectively. Significant differences for grade and stage of disease at liver biopsy were observed for DQB1*0501 and DQB1*0201 alleles; P ‫؍‬ .019, r s ‫؍‬ .64, and P ‫؍‬ .047, r s ‫؍‬ .57, respectively. In addition, significant differences in stage of disease were found to exist between DRB1*13 and DRB1*0701, P ‫؍‬ .031, r s ‫؍‬ ؊.71. The rate of disease progression in chronic hepatitis C is variable and influenced by both viral and host-related factors. Relevant virus-related factors might include size of inoculum, quasispecies diversity, and genotype. Transfusion-associated infection has a more rapid progression to active liver disease than needle stick-associated infection. 1,2 This is presumably related to the smaller viral burden at exposure for the latter case. Hepatitis C viral production is estimated to reach 10 10 to 10 13 virions/day with a short half-life of several hours. [3][4][5][6] The magnitude of the serum viral load has relevance for the success of antiviral therapy. Serum viremia at or below the threshold of 6.3 log 10 viral copies/mL is a good prognostic indicator of likely response to either interferon monotherapy or interferon and ribavirin combination therapy. 7-9 Similar to the human immunodeficiency virus (HIV), the high turnover rates and error-prone replication exhibited by the hepatitis C virus (HCV) provides a mechanism for the generation of immune escape and antiviral therapy-resistant mutants. [10][11][12][13] Host factors that influence disease progression in individuals infected with HCV include age at exposure, excessive alcohol consumption, and the presence of competing causes for liver disease such as the hepatitis B virus and hepatitis A virus superinfection. Individuals infected with HCV who are greater than 50 years of age have a more severe disease and higher mortality rate than younger individuals. 14,15 The genetic background of the host as assessed by human leukocyteassociated antigen (HLA) typing has shown some associations with clearance of ...

Hepatitis C virus (HCV) causes chronic infection in up to 50% to 80% of infected individuals. Hypervariable region 1 (HVR1) variability is frequently studied to gain an insight into the mechanisms of HCV adaptation during chronic infection, but the changes to and persistence of HCV subpopulations during intrahost evolution are poorly understood. In this study, we used ultradeep pyrosequencing (UDPS) to map the viral heterogeneity of a single patient over 9.6 years of chronic HCV genotype 4a infection. Informed error correction of the raw UDPS data was performed using a temporally matched clonal data set. The resultant data set reported the detection of low-frequency recombinants throughout the study period, implying that recombination is an active mechanism through which HCV can explore novel sequence space. The data indicate that polyvirus infection of hepatocytes has occurred but that the fitness quotients of recombinant daughter virions are too low for the daughter virions to compete against the parental genomes. The subpopulations of parental genomes contributing to the recombination events highlighted a dynamic virome where subpopulations of variants are in competition. In addition, we provide direct evidence that demonstrates the growth of subdominant populations to dominance in the absence of a detectable humoral response. IMPORTANCEAnalysis of ultradeep pyrosequencing data sets derived from virus amplicons frequently relies on software tools that are not optimized for amplicon analysis, assume random incorporation of sequencing errors, and are focused on achieving higher specificity at the expense of sensitivity. Such analysis is further complicated by the presence of hypervariable regions. In this study, we made use of a temporally matched reference sequence data set to inform error correction algorithms. Using this methodology, we were able to (i) detect multiple instances of hepatitis C virus intrasubtype recombination at the E1/E2 junction (a phenomenon rarely reported in the literature) and (ii) interrogate the longitudinal quasispecies complexity of the virome. Parallel to the UDPS, isolation of IgG-bound virions was found to coincide with the collapse of specific viral subpopulations.

No abstract

Hepatitis C virus (HCV) exists as a quasispecies within an infected individual. We have previously reported an in-frame 3 bp insertion event at the N-terminal region of the E2 glycoprotein from a genotype 4a HCV isolate giving rise to an atypical 28 aa hypervariable region (HVR) 1. To further explore quasispecies evolution at the HVR1, serum samples collected over 9.6 years from the same chronically infected, treatment naïve individual were subjected to retrospective clonal analysis. Uniquely, we observed that isolates containing this atypical HVR1 not only persisted for 7.6 years, but dominated the quasispecies swarm. Just as striking was the collapse of this population of variants towards the end of the sampling period in synchrony with variants containing a classical HVR1 from the same lineage. The replication space was subsequently occupied by a second minor lineage, which itself was only intermittently detectable at earlier sampling points. In conjunction with the observed genetic shift, the coexistence of two distinct HVR1 populations facilitated the detection of putative intra-subtype recombinants, which included the identification of the likely ancestral parental donors. Juxtaposed to the considerable plasticity of the HVR1, we also document a degree of mutational inflexibility as each of the HVR1 subpopulations within our dataset exhibited overall genetic conservation and convergence. Finally, we raise the issue of genetic analysis in the context of mixed lineage infections.

A large cohort of rhesus-negative women in Ireland were inadvertently infected with hepatitis C virus following exposure to contaminated anti-D immunoglobulin in 1977-8. This major iatrogenic episode was discovered in 1994. We studied 36 women who had been infected after their first pregnancy, and compared them to an age- and parity-matched control group of rhesus-positive women. The presence of hepatitis C antibody was confirmed in all 36 by enzyme-linked immunosorbent assay and by recombinant immunoblot assay, while 26 (72%) of the cohort were HCV-RNA-positive (type 1b) on PCR testing. In the 20 years post-infection, all members of the study group had at least one pregnancy, and mean parity was 3.5. They had a total of 100 pregnancies and 85 of these went to term. There were four premature births, one being a twin pregnancy, and 11 spontaneous miscarriages. One miscarriage occurred in the pregnancy following HCV infection. There were two neonatal deaths due to severe congenital abnormalities in the PCR-positive women. Of the children born to HCV-RNA positive mothers, only one (2.3%) tested positive for the virus. Significant portal fibrosis on liver biopsy was confined to HCV-RNA-positive mothers apart from one single exception in the antibody-positive HCV-RNA-negative group. Comparison with the control group showed no increase in spontaneous miscarriage rate, and no significant difference in obstetric complications; birth weights were similar for the two groups.