Resolved Hepatitis C Virus Infection Research Articles

Efficacy and safety of rituximab in patients with PLA2R associated membranous nephropathy and resolved HCV infection

Rituximab occasionally induces reactivation of hepatitis C virus (HCV) in patients with resolved HCV infection, sometimes with fatal consequences. As rituximab has become one of the first-line therapies for the treatment of phospholipase A2 receptor (PLA2R)-associated membranous nephropathy (MN) and is more widely used, there is a lack of studies reporting the effectiveness and safety of rituximab in patients with PLA2R-associated MN and resolved HCV infection. A single-center retrospective study was conducted on PLA2R-associated membranous nephropathy (MN) patients who were HCVAb positive but HCV-RNA negative and treated with rituximab. A total of 598 adult patients with PLA2R-associated MN who underwent rituximab therapy were screened. General clinical information, including gender, age, pathological data, and previous treatment plans, was collected from medical records. Routine blood tests, liver and kidney function assessments, blood lipid profiles, 24-h urine protein levels, anti-PLA2R antibody titers, circulating B-cell counts, and HCV viral loads were measured at the time of rituximab infusion and repeated at intervals of 1–3 months post-rituximab administration. A total of 8 patients were enrolled, with a median follow-up period of 19.00 (range: 16.00–25.25) months. Among the 8 patients, 5 were male, and the mean age was 50.13 ± 4.29 years. Histological findings indicated that tubuloreticular inclusions, mesangial deposits, intramembranous deposits, and subendothelial deposits were not observed in any of the 8 patients. The overall 1-year remission rate for these patients was 75%, accompanied by a significant reduction in proteinuria. Additionally, blood albumin levels increased significantly, and renal function remained stable. No increase in HCV viral load and stable liver function tests were observed throughout the entire follow-up period. This study suggested that on the basis of successful eradication of HCV virus with antiviral drugs, rituximab can effectively induce clinical remission of patients with PLA2R associated MN and resolved HCV infection, and does not lead to a significant increase in HCV virus load. However, this finding is based on a very small sample size and should be confirmed in larger clinical trials.

Discovery of a monoclonal, high-affinity CD8+ T-cell clone following natural hepatitis C virus infection.

CD8+ Tcells recognizing their cognate antigen are typically recruited as a polyclonal population consisting of multiple clonotypes with varying T-cell receptor (TCR) affinity to the target peptide-major histocompatibility complex (pMHC) complex. Advances in single-cell sequencing have increased accessibility toward identifying TCRs with matched antigens. Here we present the discovery of a monoclonal CD8+ T-cell population with specificity for a hepatitis C virus (HCV)-derived human leukocyte antigen (HLA) class I epitope (HLA-B*07:02 GPRLGVRAT) which was isolated directly ex vivo from an individual with an episode of acutely resolved HCV infection. This population was absent before infection and underwent expansion and stable maintenance for at least 2 years after infection as measured by HLA-multimer staining. Furthermore, the monoclonal clonotype was characterized by an unusually long dissociation time (half-life = 794 s and koff = 5.73 × 10-4) for its target antigen when compared with previously published results. A comparison with related populations of HCV-specific populations derived fromthe same individual and a second individual suggested that high-affinity TCR-pMHC interactions may be inherent to epitope identity and shape the phenotype of responses which has implications for rational TCR selection and design in the age of personalized immunotherapies.

Liver stiffness and associated risk factors among people with a history of injecting drugs: a prospective cohort study

BackgroundPersons with opioid use disorders (OUD) and persons with substance use disorders (SUD) who inject substances have a reduced life expectancy of up to 25 years compared with the general population. Chronic liver diseases are a substantial cause of this. Screening strategies based on liver stiffness measurements (LSM) may facilitate early detection, timely intervention, and treatment of liver disease. This study aims to investigate the extent of chronic liver disease measured with transient elastography and the association between LSM and various risk factors, including substance use patterns, hepatitis C virus (HCV) infection, alcohol use, body mass index, age, type 2 diabetes mellitus, and high-density lipoprotein (HDL) cholesterol among people with OUD or with SUD who inject substances.MethodsData was collected from May 2017 to March 2022 in a cohort of 676 persons from Western Norway. The cohort was recruited from two populations: Persons receiving opioid agonist therapy (OAT) (81% of the sample) or persons with SUD injecting substances but not receiving OAT. All participants were assessed at least once with transient elastography. A linear mixed model was performed to assess the impact of risk factors such as HCV infection, alcohol use, lifestyle-associated factors, and substance use on liver stiffness at baseline and over time. Baseline was defined as the time of the first liver stiffness measurement. The results are presented as coefficients (in kilopascal (kPa)) with 95% confidence intervals (CI).ResultsAt baseline, 12% (n = 83) of the study sample had LSM suggestive of advanced chronic liver disease (LSM ≥ 10 kPa). Advanced age (1.0 kPa per 10 years increments, 95% CI: 0.68;1.3), at least weekly alcohol use (1.3, 0.47;2.1), HCV infection (1.2, 0.55;1.9), low HDL cholesterol level (1.4, 0.64;2.2), and higher body mass index (0.25 per increasing unit, 0.17;0.32) were all significantly associated with higher LSM at baseline. Compared with persistent chronic HCV infection, a resolved HCV infection predicted a yearly reduction of LSM (-0.73, -1.3;-0.21) from baseline to the following liver stiffness measurement.ConclusionsMore than one-tenth of the participants in this study had LSM suggestive of advanced chronic liver disease. It underscores the need for addressing HCV infection and reducing lifestyle-related liver risk factors, such as metabolic health factors and alcohol consumption, to prevent the advancement of liver fibrosis or cirrhosis in this particular population.

Hepatitis C Virus Reactivation in Anti-HCV Antibody-Positive Patients with Chronic Hepatitis B Following Anti-HBV Therapies.

Background and Aims: Whether hepatitis C virus (HCV) reactivation occurs and how the viral load evolves in anti-HCV antibody-positive chronic hepatitis B (CHB) patients who underwent nucleos(t)ide analogue (Nuc) therapies remain unsolved. Methods: A cohort of 66 such patients was studied. Results: At the start of Nuc treatment (baseline), all patients had detectable hepatitis B virus (HBV) DNA levels (6.05 ± 1.88 log IU/mL), while HCV RNA levels (3.79 ± 1.43 log IU/mL) were detected (i.e., chronic hepatitis C (CHC)) in only 13 patients (19.7%). Following Nuc therapies, HBV DNA levels reached the nadirs at end of therapy (EOT) (6.05 ± 1.88 vs. 0.25 ± 0.99 log IU/mL, p < 0.0001) and relapsed at 6 months after EOT (6mEOT) at a level of 3.45 ± 2.64 log IU/mL compared with EOT (p < 0.0001). Among the 13 CHC patients, a non-significant decrease in HCV RNA was noted at EOT (3.52 ± 1.71 vs. 2.77 ± 2.63 log IU/mL, p = 0.166) but tended to decrease further at 6mEOT (2.77 ± 2.63 vs. 1.89 ± 2.06 log IU/mL, p = 0.063). Two of the thirteen CHC patients showed an increase in HCV-RNA ≥ 1 log10 IU/mL at EOT, and one of the fifty-three patients with undetectable HCV RNA at baseline (i.e., resolved past HCV infection) showed detectable HCV RNA at year 1 (3200 IU/mL) and year 2 (1240 IU/mL) following entecavir therapy. Conclusions: HCV reactivation did occur during HBV suppression, and the rate was 4.5% (3/66), 15.4% (2/13), and 1.9% (1/53), for all patients, CHC patients, and patients with resolved past HCV infection, respectively. The reverse HBV and HCV viral evolutions at 6mEOT indicate that HBV relapse may suppress HCV replication again.

Association of hepatitis C virus infection status and genotype with kidney disease risk: A population-based cross-sectional study.

BackgroundWhether there is difference in kidney disease risk between chronic hepatitis C virus (HCV) infection and resolved HCV infection remains inconclusive. Additionally, the impact of different HCV genotypes on kidney disease risk is relatively unknown. Accordingly, we conducted a population-based cross-sectional study to investigate the association of HCV infection status and genotype on kidney disease risk.MethodsThe study population were adult participants of 1999–2018 National Health and Nutrition Examination Survey in the United States. Chronic and resolved infection were defined as HCV seropositivity with and without detectable HCV RNA, respectively. HCV genotypes were classified into genotype 1, genotype 2, and other genotypes. Prevalent estimated glomerular filtration rate < 60 ml/min/1.73 m2 or urinary albumin creatinine ratio ≥ 30 mg/g was defined as kidney disease.ResultsThe average age of study population (n = 44,998) was 46.7±17.0 years with 49.8% being males. Compared with individuals without HCV infection (n = 44,157), those with resolved (n = 255) or chronic HCV infection (n = 586) had higher prevalence of kidney disease: 14.8%, 23.5%, and 20.1%, respectively (p<0.001). After adjusting for potential confounders, we found that both resolved (adjusted OR: 1.40, 95% CI: 1.02–1.93) and chronic HCV infection (adjusted OR: 1.26, 95% CI: 1.01–1.57) correlated to increased kidney disease risk compared with no HCV infection. Additionally, individuals with HCV genotype 1 (adjusted OR: 1.41, 95% CI: 1.09–1.82) but not genotype 2 or other genotypes had greater kidney disease risk compared with no HCV infection. Furthermore, we observed that genotype 1 had 2-fold higher kidney disease risk (adjusted OR: 2.20, 95% CI: 1.07–4.53) compared with non-genotype 1 HCV infection.ConclusionBoth resolved and chronic HCV infection, particularly genotype 1, were associated with higher kidney disease risk.

Peripheral blood iNKT cell activation correlates with liver damage during acute hepatitis C.

Invariant NK T (iNKT) cells are implicated in viral clearance; however, their role in hepatitis C virus (HCV) infection remains controversial. Here, iNKT cells were studied during different stages of HCV infection. iNKT cells from patients with acute HCV infection and people who inject drugs (PWID) with chronic or spontaneously resolved HCV infection were characterized by flow cytometry. In a longitudinal analysis during acute HCV infection, frequencies of activated CD38+ iNKT cells reproducibly declined in spontaneously resolving patients, whereas they were persistently elevated in patients progressing to chronic infection. During the first year of infection, the frequency of activated CD38+ or CD69+ iNKT cells strongly correlated with alanine transaminase levels with particularly pronounced correlations in spontaneously resolving patients. Increased frequencies of activated iNKT cells in chronic HCV infection were confirmed in cross-sectional analyses of PWID with chronic or spontaneously resolved HCV infection; however, no apparent functional differences were observed with various stimulation protocols. Our data suggest that iNKT cells are activated during acute hepatitis C and that activation is sustained in chronic infection. The correlation between the frequency of activated iNKT cells and alanine transaminase may point toward a role of iNKT cells in liver damage.

Trends in the Prevalence of Hepatitis C Virus Infection based on the Insurance Status in the United States from 2013 to 2018.

With the recent improvement in the treatment of hepatitis C virus (HCV) infection, a better understanding of the infection burden is needed. We aimed to (a) estimate the trends in the national prevalence of HCV infection based on the type of health insurance coverage and (b) identify at-risk populations for HCV infection in the United States (US) general population. Population-based analyses using the National Health and Nutrition Examination Survey (2013-2018) were performed with a focus on HCV infection. We analysed the prevalence of HCV infection based on the health insurance status before the direct-acting antiviral (DAA) era (2013-2014) and during the DAA era (2015-2018). The age-adjusted prevalence of active HCV infection (HCV RNA [+]) was 0.92% (95% confidence interval, 0.71%-1.19%) in the US non-institutionalized civilian population. Although the prevalence of active HCV infection has remained stable, the prevalence of resolved HCV infection has increased after the introduction of DAA. In terms of health insurance coverage, the prevalence of active HCV infection decreased, and the prevalence of resolved HCV infection increased among individuals who had health insurance, especially private health insurance. The independent risk factors of active HCV infection were 40-69years group, male, less than high school education, unmarried, below poverty status, being born in the US, history of blood transfusion and not having private health insurance. The burden of active HCV infection has decreased among individuals who had health insurance, especially private health insurance, during the DAA era.

Laboratory-based dried blood spot testing for hepatitis C: A protocol for systematic review and meta-analysis of diagnostic accuracy

Background: Diagnosis of chronic hepatitis C virus (HCV) infection typically involves collection of venous blood samples prior to serological investigation of an antibody response followed by a confirmatory viral load or antigen test to verify active HCV infection. This conventional pathway poses logistical challenges for the implementation of reflex testing, whereby the confirmatory test is performed on the same sample used for serological investigation. Dried blood spot (DBS) testing, in which capillary blood is deposited on filter paper, is a less invasive alternative that can enable reflex testing without the need for venepuncture, centrifugation and freezing of samples. Methods: This systematic review aims to assess the diagnostic accuracy of DBS compared with venous blood samples for diagnosis of chronic HCV infection. Observational studies which compare diagnostic tests using DBS with those using serum, plasma or whole blood in patients with chronic or resolved HCV infection will be included. Electronic searches will be conducted in PubMed, Embase, Scopus, Web of Science, Lilacs and the Cochrane library. Citation screening, data extraction and quality appraisal of included studies will be performed in duplicate using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. A meta-analysis will be conducted to derive pooled estimates of sensitivity, specificity, positive likelihood ratios, negative likelihood ratios, and diagnostic odds ratios. Sensitivity analyses and meta-regression will also be performed. Quality of the evidence will be evaluated using the GRADE criteria. Discussion: Identifying and linking people with currently undiagnosed chronic HCV infection to care is pivotal to attaining global viral hepatitis elimination targets. The use of DBS could simplify diagnostic testing strategies by integrating reflex testing into the care pathway and reducing drop-off along the cascade of care. Registration: PROSPERO, CRD42020205204. Registered 19 th September 2020.

Laboratory-based dried blood spot testing for hepatitis C: A protocol for systematic review and meta-analysis of diagnostic accuracy.

Background: Diagnosis of chronic hepatitis C virus (HCV) infection typically involves collection of venous blood samples prior to serological investigation of an antibody response followed by a confirmatory viral load or antigen test to verify active HCV infection. This conventional pathway poses logistical challenges for the implementation of reflex testing, whereby the confirmatory test is performed on the same sample used for serological investigation. Dried blood spot (DBS) testing, in which capillary blood is deposited on filter paper, is a less invasive alternative that can enable reflex testing without the need for venepuncture, centrifugation and freezing of samples. Methods: This systematic review aims to assess the diagnostic accuracy of DBS compared with venous blood samples for diagnosis of chronic HCV infection. Observational studies which compare diagnostic tests using DBS with those using serum, plasma or whole blood in patients with chronic or resolved HCV infection will be included. Electronic searches will be conducted in PubMed, Embase, Scopus, Web of Science, Lilacs and the Cochrane library. Citation screening, data extraction and quality appraisal of included studies will be performed in duplicate using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. A meta-analysis will be conducted to derive pooled estimates of sensitivity, specificity, positive likelihood ratios, negative likelihood ratios, and diagnostic odds ratios. Sensitivity analyses and meta-regression will also be performed. Quality of the evidence will be evaluated using the GRADE criteria. Discussion: Identifying and linking people with currently undiagnosed chronic HCV infection to care is pivotal to attaining global viral hepatitis elimination targets. The use of DBS could simplify diagnostic testing strategies by integrating reflex testing into the care pathway and reducing drop-off along the cascade of care. Registration: PROSPERO, CRD42020205204. Registered 19 th September 2020.

Association of Interleukin 28B Polymorphism with Clearance of Hepatitis C Virus: A Mini Review.

The highly infectious hepatitis C virus (HCV) is the major cause of chronic hepatitis around the globe. Approximately 3% of the world's population has been affected by both chronic and acute HCV. In this study, we highlight the relationship between single-nucleotide proteins (SNPs) and interleukin (IL) IL28B on chromosome 19 with the treatment response of chronic HCV infection along with its sustained virologic response (SVR). Four SNPs are strongly linked with HCV self-clearance: rs8099917 TT, rs12980275 AA, rs8105790 TT, and rs10853728 CC. Most SNPs, including rs12979860, are located upstream of the IL28B gene fragment, encoding interferon (IFN)-λ3. We find that IL28B variants rs8099917 and rs12979860 strongly influence results of combined pegylated (PEG)-IFN/ribavirin (RBV) therapy. In the case of SNP rs12979860, the CC genotype is linked with greater than a twofold higher SVR than that with TT or CT genotypes. These SNPs are associated with expression of intrahepatic IFN-stimulated genes in liver. Past research shows that females are more efficient in resolving HCV infection, regardless of IL28B genotype. Similar results of IL28B polymorphisms associated with spontaneous HCV clearance were also obtained in Chinese and Taiwanese HCV patients. Another report of RBV and PEG-IFN-treated patients revealed that age, viral load, rs8099917 genotype, and fibrosis were major predictors of antiviral therapeutic response. To select favorable antiviral regimes for treatment using IFN, a combination of host genetic data and viral genotyping may be useful in treating chronic HCV. We propose that these predictive factors must be considered before commencing treatment in HCV patients.

Differential Reactivity of anti-hepatitis C Virus Screening Assays in Patients With Waning Antibodies

Hepatitis C virus (HCV) leads to persistent infection. Viral clearance can be obtained through pharmacological treatment or spontaneously. After viral clearance, anti-HCV antibodies (Abs) slowly decline and finally disappear. Subjects with a resolved HCV infection are reactive to anti-HCV screening assays for a long time. These subjects pose a diagnostic challenge, and therefore, a more accurate interpretation of laboratory tests is needed for cases with resolved HCV infection. However, the performances of anti-HCV screening assays against declining anti-HCV Abs have not been assessed. Here we evaluated 1509 samples with different screening assays. Screening assays provided discrepant results in patients with waning Abs. The identification of signal-to-cut-off values indicative of waning Abs for each anti-HCV assay could avoid unnecessary confirmatory tests and reduce the impact of misdiagnosis.

Circulating and inducible IL-32α in chronic hepatitis C virus infection

Background: Interleukin 32 (IL-32) is a recently described pro-inflammatory cytokine implicated in chronic hepatitis C virus (HCV)-related inflammation and fibrosis. IL-32α is the most abundant IL-32 isoform. Methods: Circulating IL-32α levels were documented in patients with chronic HCV infections ( n = 31) and compared with individuals who spontaneously resolved HCV infection ( n = 14) and HCV-naive controls ( n = 20). In addition, peripheral blood mononuclear cells (PBMC) from the chronic HCV ( n = 12) and HCV-naive ( n = 9) cohorts were investigated for responses to HCV core and non-structural (NS)3 protein induced IL-32α production. Finally, correlations between IL-32α levels, hepatic fibrosis and subsequent responses to interferon-based therapy were documented in patients with chronic HCV. Results: Circulating IL-32α levels in patients with chronic HCV were similar to those of spontaneously resolved and HCV-naive controls. HCV protein induced IL-32α responses were similar in chronic HCV patients and HCV-naive controls. In patients with chronic HCV, serum IL-32α levels correlated with worsening METAVIR fibrosis (F) scores from F0 to F3 ( r = 0.596, P &lt; 0.001) as did NS3 induced IL-32α responses ( r = 0.837, P &lt; 0.05). However, these correlations were not sustained with the inclusion of IL-32α levels at F4 scores, suggesting events at F4 interfere with IL-32α synthesis or release. In chronic HCV patients who underwent treatment ( n = 28), baseline in vivo and in vitro induced IL-32α concentrations were not predictive of therapeutic outcomes. Conclusions: IL-32α activity is associated with worsening fibrosis scores in non-cirrhotic, chronic HCV patients.

Circulating and inducible IL-32α in chronic hepatitis C virus infection.

Interleukin 32 (IL-32) is a recently described pro-inflammatory cytokine implicated in chronic hepatitis C virus (HCV)-related inflammation and fibrosis. IL-32α is the most abundant IL-32 isoform. Circulating IL-32α levels were documented in patients with chronic HCV infections (n = 31) and compared with individuals who spontaneously resolved HCV infection (n = 14) and HCV-naive controls (n = 20). In addition, peripheral blood mononuclear cells (PBMC) from the chronic HCV (n = 12) and HCV-naive (n = 9) cohorts were investigated for responses to HCV core and non-structural (NS)3 protein induced IL-32α production. Finally, correlations between IL-32α levels, hepatic fibrosis and subsequent responses to interferon-based therapy were documented in patients with chronic HCV. Circulating IL-32α levels in patients with chronic HCV were similar to those of spontaneously resolved and HCV-naive controls. HCV protein induced IL-32α responses were similar in chronic HCV patients and HCV-naive controls. In patients with chronic HCV, serum IL-32α levels correlated with worsening METAVIR fibrosis (F) scores from F0 to F3 (r = 0.596, P < 0.001) as did NS3 induced IL-32α responses (r = 0.837, P < 0.05). However, these correlations were not sustained with the inclusion of IL-32α levels at F4 scores, suggesting events at F4 interfere with IL-32α synthesis or release. In chronic HCV patients who underwent treatment (n = 28), baseline in vivo and in vitro induced IL-32α concentrations were not predictive of therapeutic outcomes. IL-32α activity is associated with worsening fibrosis scores in non-cirrhotic, chronic HCV patients.

Performance of a new rapid diagnostic test for the detection of antibodies to hepatitis C virus

Rapid diagnostic tests (RDTs) represent an attractive alternative to conventional diagnostic methods for hepatitis C virus (HCV) infection.The aim of the present study was to assess the clinical performance of the new CE-marked Advanced Quality™ Rapid Anti-HCV Test for the detection of HCV antibodies in various patient populations.A total of 396 individuals, including 178 patients with chronic HCV infection, 26 patients with resolved HCV infection, and 192 subjects not infected with HCV, were studied.The clinical sensitivity and specificity in serum samples of the Advanced Quality™ Rapid Anti-HCV Test were both 99%.The new CE-marked RDT Advanced Quality™ Rapid Anti-HCV Test fulfills the World Health Organization recommendations acceptance criteria for serological assays in terms of sensitivity and specificity and can thus be confidently used for the screening of HCV antibodies.

Relation of Reduction of Antibodies against Hepatitis B Virus to Hepatocellular Carcinoma Recurrence in the Patients with Resolved Hepatitis B Virus Infection Following Direct-acting Antiviral Therapy for Hepatitis C Virus Infection.

ABSTRACTBackgroundA possible interaction of hepatitis viruses at cellular and molecular levels has been suggested. Eradication of hepatitis C virus (HCV) has been reported to induce activation of hepatitis B virus (HBV)-related liver diseases.Materials and methodsThe present study examined association of HBV markers with recurrence of hepatocellular carcinoma (HCC) in patients with resolved HCV infection by direct-acting antiviral (DAA) therapy. In a patient pool of 378 patients with sustained virologic response (SVR) by DAA, the antibody to the hepatitis B surface antigen (anti-HBs), the antibody to the hepatitis B core antigen (anti-HBc), and HBV-DNA levels were estimated before and at the end of DAA therapy. These patients were HBsAg negative. Eighty-nine patients had a history of curative treatment of HCC by resection or radiofrequency ablation. A Cox proportional hazards model was used to identify risk factors for HCC recurrence, including the change ratio of the antibody against HBV proteins.ResultsAlthough 188 patients had resolved HBV infection, no patient showed HBV reactivation, but anti-HBs and anti-HBc levels decreased significantly. No significant difference in the HCC recurrence rate was evident between patients with and without resolved HBV infection. Changes of immune responses to HBV proteins did not affect HCC recurrence after DAA therapy for HCV infection in this cohort.ConclusionThe mechanisms underlying diverse roles of DAA-induced SVR of HCV on HBV kinetics need to be resolved in future.How to cite this articleJoko K, Mashiba T, Ochi H, et al. Relation of Reduction of Antibodies against Hepatitis B Virus to Hepatocellular Carcinoma Recurrence in the Patients with Resolved Hepatitis B Virus Infection Following Direct-acting Antiviral Therapy for Hepatitis C Virus Infection. Euroasian J Hepato-Gastroenterol 2019;9(2):78–83.

HLA-Bw4 80(T) and multiple HLA-Bw4 copies combined with KIR3DL1 associate with spontaneous clearance of HCV infection in people who inject drugs

Natural killer (NK) cell function is regulated by inhibitory and activating receptors including killer cell immunoglobulin-like receptors (KIRs). Here, we analyzed the impact of different KIR/KIR-ligand genotypes on the outcome of hepatitis C virus (HCV) infection in people who inject drugs (PWID). KIR/KIR-ligand genotypes associated with spontaneous clearance of HCV infection were identified in a cohort of PWID from Germany (n=266) and further validated in a second anti-HCV positive cohort of PWID recruited in North America (n=342). NK cells of PWID and healthy donors were functionally characterized according to their KIR/KIR-ligand genotype by flow cytometry. Multivariate logistic regression analysis revealed that KIR3DL1/HLA-Bw4 80(T) was associated with spontaneous clearance of HCV infection in PWID, which was confirmed in the PWID cohort from North America. Compared with PWID with detectable HCV RNA, the frequency of individuals with multiple HLA-Bw4 alleles was significantly higher in anti-HCV positive PWID with resolved HCV infection (29.7% vs. 15.2%; p=0.0229) and in anti-HCV seronegative PWID (39.2%; p=0.0006). KIR3DL1+ NK cells from HLA-Bw4 80(T)-positive PWID showed superior functionality compared to HLA-Bw4 80(I)-positive PWID. This differential impact was not observed in healthy donors; however, the HLA-Bw4 copy number strongly correlated with the functionality of KIR3DL1+ NK cells. HLA-Bw4-80(T) and multiple HLA-Bw4 copies in combination with KIR3DL1 are associated with protection against chronic hepatitis C in PWID by distinct mechanisms. Better licensing of KIR3DL1+ NK cells in the presence of multiple HLA-Bw4 copies is beneficial prior to seroconversion whereas HLA-Bw4 80(T) may be beneficial during acute hepatitis C. Lay summary: Natural killer (NK) cells are part of the innate immune system and are regulated by a complex network of activating and inhibiting receptors. The regulating receptor-ligand pairs of an individual are genetically determined. Here, we identified a particular set of ligand and receptor genes that are associated with better functionality of NK cells and better outcome upon exposure to HCV in a high-risk group.

Does active hepatitis C virus infection increase the risk for infection due to Staphylococcus aureus?

Infections with Staphylococcus aureus may be more frequent in subjects with active hepatitis C virus (HCV) infection. In this retrospective dual-cohort study, we sought to determine whether persons with active HCV infection (positive HCV antibody, detectable blood HCV RNA) were at greater risk of S. aureus infection than those with spontaneously resolved HCV infection (positive HCV antibody, negative blood HCV RNA). Based on prestudy power calculation, we included 231 subjects with active HCV and 116 subjects with resolved HCV infection. The two groups were well matched at baseline, except that subjects with active HCV had a higher mean Charlson's comorbidity index (2.2 vs. 1.3; p < 0.0001). Cohorts were followed for a mean of 3.67years. Thirty-one of the 231 (13%) subjects with active HCV infection developed ≥1 S. aureus infection(s) as compared to 4/116 (3.4%) subjects with resolved HCV (p = 0.004), with a trend towards more recurrent S. aureus infections in subjects with active HCV infection. The S. aureus infections were mostly serious, necessitating hospitalization and intravenous antibiotics. In the logistic regression, factors that independently predicted S. aureus infection were active HCV and Charlson's comorbidity index. Our regression models confirmed that the enhanced susceptibility to S. aureus infections was related to active HCV infection and not attributable solely to the increased number of comorbidities [adjusted odds ratio (OR) = 3.3, 95% confidence interval (CI) 1.1-9.8; p = 0.03]. This study shows that subjects with active HCV infection have a significantly higher incidence of serious S. aureus infections than those with spontaneously resolved HCV, even after adjustment for comorbidities.

Prospective assessment of rapid diagnostic tests for the detection of antibodies to hepatitis C virus, a tool for improving access to care

Large-scale hepatitis C screening is required to prevent further spread of the infection, improve access to care in the context of new hepatitis C virus (HCV) drug regimens without interferon-alpha and subsequently reduce the risk of long-term complications of chronic liver disease. Rapid diagnostic tests (RDTs) represent an attractive alternative to enzyme immunoassay using blood from venepuncture. The aim of the present study was to prospectively assess the clinical performance of CE-marked RDTs detecting anti-HCV antibodies in fingerstick capillary whole blood and/or oral fluid. A total of 513 individuals, including 318 patients with chronic HCV infection, 25 patients with resolved HCV infection and 170 HCV-seronegative individuals, were prospectively enrolled. The specificity of RDTs with fingerstick whole blood varied from 98.8% to 100%. The clinical sensitivity was high for the OraQuick® and Toyo® tests (99.4% and 95.8%, respectively), but low for the Labmen® test (63.1%). The specificity and clinical sensitivity in crevicular fluid were both satisfactory for the OraQuick® test (100% and 97.6%, respectively). HCV antibody RDTs were easy and rapid to perform in the context of patient care. They were highly specific. Both the OraQuick® and Toyo® tests reached the expected level of performance for wide-scale use, with a performance advantage for the OraQuick® HCV test. RDTs appear to be a promising new tool for wide-scale screening of HCV infection in high-risk to medium-risk populations. Hence, careful assessment of the performance of HCV RDTs must be recommended before they can be implemented in clinical practice.

The interaction of genetic determinants in the outcome of HCV infection: evidence for discrete immunological pathways.

Diversity within the innate and adaptive immune response to hepatitis C is important in determining spontaneous resolution (SR) and treatment response. The aim of this study was to analyze how these variables interact in combination; furthering our understanding of the mechanisms that drive successful immunological clearance. Multivariate analysis was performed on retrospectively collected data for 357 patients previously genotyped for interferon (IFN)‐λ3/4, killer cell immunoglobulin (KIR), human leukocyte antigen (HLA) class I and II and tapasin. High resolution KIR genotyping was performed for individuals with chronic infection and haplotypes determined. Outcomes for SR, IFN response and cirrhosis were examined. Statistical analysis included univariate methods, χ2 test for trend, multivariate logistic regression, synergy and principal component analysis (PCA). Although KIR2DL3:HLA‐C1C1 (P = 0.027), IFN‐λ3/4 rs12979860 CC (P = 0.027), tapasin G in individuals with aspartate at residue 114 of HLA‐B (TapG:HLA‐B114D) (P = 0.007) and HLA‐DRB1*04:01 (P = 0.014) were associated with SR with a strong additive influence (χ2 test for trend P < 0.0001); favorable polymorphisms did not interact synergistically, nor did patients cluster by outcome. In the treatment cohort, IFN‐λ3/4 rs12979860 CC was protective in hepatitis C virus (HCV) G1 infection and KIR2DL3:HLA‐C1 in HCV G2/3. In common with SR, variables did not interact synergistically. Polymorphisms predictive of viral clearance did not predict disease progression. In summary, different individuals resolve HCV infection using discrete and non‐interacting immunological pathways. These pathways are influenced by viral genotype. This work provides novel insights into the complexity of the interaction between host and viral factors in determining the outcome of HCV infection.

Differential distribution of IL28B.rs12979860 single-nucleotide polymorphism among Egyptian healthcare workers with and without a hepatitis C virus-specific cellular immune response.

The CC genotype of the interleukin (IL)-28B.rs12979860 gene has been associated with spontaneous hepatitis C virus (HCV) clearance and treatment response. The distribution and correlation of an IL28B.rs12979860 single-nucleotide polymorphism (SNP) with HCV-specific cell-mediated immune (CMI) responses among Egyptian healthcare workers (HCWs) is not known. We determined this relationship in 402 HCWs who serve a patient cohort with ~85% HCV prevalence. We enrolled 402 HCWs in four groups: group 1 (n = 258), seronegative aviremic subjects; group 2 (n = 25), seronegative viremic subjects; group 3 (n = 41), subjects with spontaneously resolved HCV infection; and group 4 (n = 78), chronic HCV patients. All subjects were tested for an HCV-specific CMI response using an ex-vivo interferon-gamma (IFNγ) ELISpot assay with nine HCV genotype-4a overlapping 15-mer peptide pools corresponding to all of the HCV proteins. All subjects were tested for IL28B.rs12979860 SNP by real-time PCR. An HCV-specific CMI was demonstrated in ~27% of the seronegative aviremic HCWs (group 1), suggesting clearance of infection after low-level exposure to HCV. The frequency of IL28B.rs12979860 C allele homozygosity in the four groups was 49%, 48%, 49%, and 23%, while that of the T allele was 14%, 16%, 12 and 19%, respectively, suggesting differential distributions among subjects with different HCV status. As reported, IL28B.rs12979860 predicted the outcome of HCV infection (p < 0.05), but we did not find any relationship between the IL28B genotypes and the outcome of HCV-specific CMI responses in the four groups (p > 0.05). The data show differential IL28B.rs12979860 genotype distribution among Egyptian HCWs with different HCV status and could not predict the outcome of HCV-specific CMI responses.