Stability and Inactivation of Monkeypox Virus on Inanimate Surfaces

The spread of nonzoonotic monkeypox virus (MPXV) infections necessitates the reevaluation of hygiene measures. To date, only limited data are available on MPXV surface stability. Here, we evaluate the stability of infectious MPXV on stainless steel stored at different temperatures, while using different interfering substances to mimic environmental contamination. MPXV persistence increased with decreasing temperature. Additionally, we were able to show that MPXV could efficiently be inactivated by alcohol- and aldehyde-based surface disinfectants. These findings underline the stability of MPXV on inanimate surfaces and support the recommendations to use alcohol-based disinfectants as prevention measures or in outbreak situations.

In-depth virological and immunological characterization of HIV-1 cure after CCR5Δ32/Δ32 allogeneic hematopoietic stem cell transplantation

Despite scientific evidence originating from two patients published to date that CCR5Δ32/Δ32 hematopoietic stem cell transplantation (HSCT) can cure human immunodeficiency virus type 1 (HIV-1), the knowledge of immunological and virological correlates of cure is limited. Here we characterize a case of long-term HIV-1 remission of a 53-year-old male who was carefully monitored for more than 9 years after allogeneic CCR5Δ32/Δ32 HSCT performed for acute myeloid leukemia. Despite sporadic traces of HIV-1 DNA detected by droplet digital PCR and in situ hybridization assays in peripheral T cell subsets and tissue-derived samples, repeated ex vivo quantitative and in vivo outgrowth assays in humanized mice did not reveal replication-competent virus. Low levels of immune activation and waning HIV-1-specific humoral and cellular immune responses indicated a lack of ongoing antigen production. Four years after analytical treatment interruption, the absence of a viral rebound and the lack of immunological correlates of HIV-1 antigen persistence are strong evidence for HIV-1 cure after CCR5Δ32/Δ32 HSCT.

Efficient Inactivation of Monkeypox Virus by World Health Organization‒Recommended Hand Rub Formulations and Alcohols

Increasing nonzoonotic human monkeypox virus (MPXV) infections urge reevaluation of inactivation strategies. We demonstrate efficient inactivation of MPXV by 2 World Health Organization‒recommended alcohol-based hand rub solutions. When compared with other (re)emerging enveloped viruses, MPXV displayed the greatest stability. Our results support rigorous adherence to use of alcohol-based disinfectants.

Hepatitis B virus-specific CD4 T cell responses differentiate functional cure from chronic surface antigen+ infection

BACKGROUND & AIMS

With or without antiviral treatment, few individuals achieve sustained functional cure of chronic hepatitis B virus (HBV) infection. A better definition of what mediates functional cure is essential for improving immunotherapeutic strategies. We aimed to compare HBV-specific T cell responses in patients with different degrees of viral control.

METHODS

We obtained blood from 124 HBV-infected individuals, including those with acute self-limiting HBV infection, chronic infection, and chronic infection with functional cure. We screened for HBV-specific T cell specificities by ELISpot, assessed the function of HBV-specific T cells using intracellular cytokine staining, and characterized HBV-specific CD4 T cells using human leukocyte antigen (HLA) class II tetramer staining, all directly ex vivo.

RESULTS

ELISpot screening readily identified HBV-specific CD4 and CD8 T cell responses in acute resolving infection compared with more limited reactivity in chronic infection. Applying more sensitive assays revealed higher frequencies of functional HBV-specific CD4 T cells, but not CD8 T cells, in functional cure compared to chronic infection. Function independent analysis using HLA multimers also identified more HBV-specific CD4 T cell responses in functional cure compared to chronic infection, with the emergence of CD4 T cell memory both after acute and chronic infection.

CONCLUSIONS

Functional cure is associated with higher frequencies of functional HBV-specific CD4 memory T cell responses. Thus, immunotherapeutic approaches designed to induce HBV functional cure should also aim to improve CD4 T cell responses.

LAY SUMMARY

Immunotherapy is a form of treatment that relies on harnessing the power of an individual's immune system to target a specific disease or pathogen. Such approaches are being developed for patients with chronic HBV infection, in an attempt to mimic the immune response in patients who control HBV infection spontaneously, achieving a so-called functional cure. However, what exactly defines protective immune responses remains unclear. Herein, we show that functional cure is associated with robust responses by HBV-specific CD4 T cells (a type of immune cell).

Household deprivation, comorbidities and COVID-19 hospitalization in 690,115 children/adolescents

Background

Studies document that adults in disadvantaged socio-economic positions have elevated risks of a severe course of COVID-19, but it is unclear if this holds true for children. We investigate in this population-based study whether young people from socio-economically disadvantaged households in Germany had a higher risk of COVID-19 hospitalization compared with more affluent counterparts. We also examined if differences were related to comorbidities that predict severe courses in children.

Methods

We included data from all 690,115 children and adolescents (0-18 years) enrolled in a statutory health insurance carrier. Daily hospital diagnoses of COVID-19 were recorded from 1.1.2020 to 13.7.2021. Logistic regressions were used to compare children from households with an indication of poverty (e.g. long- or short-term unemployed) with children from households with insurance holders in regular employment. We also assessed socio-economic characteristics of the area of residence. We controlled for age, sex, days under observation, nationality, and comorbidities (e.g. obesity).

Findings

A COVID-19 hospital diagnosis was a rare event (n = 1637). Children of long-term unemployed parents had a 1·36 times (95% CI 1·21-1·51) higher adjusted odds of hospitalization compared with those of employed parents. Elevated odds were also found for short-term unemployed or low-wage employment. Those living in poor areas had a 3·02 (1·81-5·22) higher odds of hospitalization than those in less deprived areas. Comorbidities were strongly related to hospitalization, but their adjustment did not change main estimates for household deprivation.

Discussion

Results suggest that children from poor households are at higher risk of severe courses of COVID-19 than their affluent counterparts. This underlies the need to implement effective Public Health strategies to protect deprived children from COVID-19 and other infectious disease even in high income countries such as Germany.

Key messages

• Children and adolescents from poor families seem to be at higer risk for sever courses of COVID-19.

• Comorbidities were no key mediating factor in this study.

Transcriptional Pattern Analysis of Virus-Specific CD8+ T Cells in Hepatitis C Infection: Increased Expression of TOX and Eomesodermin During and After Persistent Antigen Recognition

Thymocyte selection-associated high mobility group box (TOX) has been described to be a key regulator in the formation of CD8+ T cell exhaustion. Hepatitis C virus (HCV) infection with different lengths of antigen exposure in acute, chronic, and after resolution of HCV infection is the ideal immunological model to study the expression of TOX in HCV-specific CD8+ T cells with different exposure to antigen. HCV-specific CD8+ T cells from 35 HLA-A*01:01, HLA-A*02:01, and HLA-A*24:02 positive patients were analyzed with a 16-color FACS-panel evaluating the surface expression of lineage markers (CD3, CD8), ectoenzymes (CD39, CD73), markers of differentiation (CD45RO, CCR7, CD127), and markers of exhaustion and activation (TIGIT, PD-1, KLRG1, CD226) and transcription factors (TOX, Eomesodermin, T-bet). Here, we defined on-target T cells as T cells against epitopes without escape mutations and off-target T cells as those against a "historical" antigen mutated in the autologous sequence. TOX+HCV-specific CD8+ T cells from patients with chronic HCV and on-target T cells displayed co-expression of Eomesodermin and were associated with the formation of terminally exhausted CD127-PD1hi, CD39hi, CD73low CD8+ T cells. In contrast, TOX+HCV-specific CD8+ T cells in patients with off-target T cells represented a progenitor memory Tex phenotype characterized by CD127hi expression and a CD39low and CD73hi phenotype. TOX+HCV-specified CD8+ T cells in patients with a sustained virologic response were characterized by a memory phenotype (CD127+, CD73hi) and co-expression of immune checkpoints and Eomesodermin, indicating a key structure in priming of HCV-specific CD8+ T cells in the chronic stage, which persisted as a residual after therapy. Overall, the occurrence of TOX+HCV-specific CD8+ T cells was revealed at each disease stage, which impacted the development of progenitor Tex, intermediate Tex, and terminally exhausted T cell through an individual molecular footprint. In sum, TOX is induced early during acute infection but is modulated by changes in viral sequence and antigen recognition. In the case of antigen persistence, the interaction with Eomesodermin leads to the formation of terminally exhausted virus-specific CD8+ T cells, and there was a direct correlation of the co-expression of TOX and Eomes and terminally exhausted phenotype of virus-specific CD8+ T cells.

Underascertainment of COVID-19 cases among first responders: a seroepidemiological study

Background

Providing frontline support places first responders at a high risk for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Aims

This study was aimed to determine the anti-SARS-CoV-2 seroprevalence in a cohort of first responders (i.e. firefighters/paramedics), to detect the underascertainment rate and to assess risk factors associated with seropositivity.

Methods

We conducted a serological survey among 745 first responders in Germany during 27 November and 4 December 2020 to determine the anti-SARS-CoV-2 seroprevalence using Elecsys® Anti-SARS-CoV-2 immunoassay (Roche Diagnostics, Mannheim, Germany). As part of the examination, participants were asked to provide information on coronavirus disease 2019 (COVID-19)-like-symptoms, information on sociodemographic characteristics and workplace risk factors for a SARS-CoV-2 infection and any prior COVID-19 infection. Descriptive statistics and logistic regression analysis were performed and seroprevalence estimates were adjusted for test sensitivity and specificity.

Results

The test-adjusted seroprevalence was 4% (95% CI 3.1–6.2) and the underascertainment rate was 2.3. Of those tested SARS-CoV-2 antibody positive, 41% were aware that they had been infected in the past. Seropositivity was elevated among paramedics who worked in the emergency rescue team providing first level of pre-hospital emergency care (6% [95% CI 3.4–8.6]) and those directly exposed to a COVID-19 case (5% [95% CI 3.5–8.1]). Overall, the seroprevalence and the underascertainment rate were higher among first responders than among the general population.

Conclusions

The high seroprevalence and underascertainment rate highlight the need to mitigate potential transmission within and between first responders and patients. Workplace control measures such as increased and regular COVID-19-testing and the prompt vaccination of all personnel are necessary.

Emergence of the E484K mutation in SARS-COV-2-infected immunocompromised patients treated with bamlanivimab in Germany

BACKGROUND

Monoclonal antibodies (mAb) have been introduced as a promising new therapeutic approach against SARS-CoV-2. At present, there is little experience regarding their clinical effects in patient populations underrepresented in clinical trials, e.g. immunocompromised patients. Additionally, it is not well known to what extent SARS-CoV-2 treatment with monoclonal antibodies could trigger the selection of immune escape viral variants.

METHODS

After identifying immunocompromised patients with viral rebound under treatment with bamlanivimab, we characterized the SARS-CoV-2-isolates by whole genome sequencing. Viral load measurements and sequence analysis were performed consecutively before and after bamlanivimab administration.

FINDINGS

After initial decrease of viral load, viral clearance was not achieved in five of six immunocompromised patients treated with bamlanivimab. Instead, viral replication increased again over the course of the following one to two weeks. In these five patients, the E484K substitution - known to confer immune escape - was detected at the time of viral rebound but not before bamlanivimab treatment.

INTERPRETATION

Treatment of SARS-CoV-2 with bamlanivimab in immunocompromised patients results in the rapid development of immune escape variants in a significant proportion of cases. Given that the E484K mutation can hamper natural immunity, the effectiveness of vaccination as well as antibody-based therapies, these findings may have important implications not only for individual treatment decisions but may also pose a risk to general prevention and treatment strategies.

FUNDING

All authors are employed and all expenses covered by governmental, federal state, or other publicly funded institutions.

Analysis of the Long-Term Impact on Cellular Immunity in COVID-19-Recovered Individuals Reveals a Profound NKT Cell Impairment

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affected over 120 million people and killed over 2.7 million individuals by March 2021. While acute and intermediate interactions between SARS-CoV-2 and the immune system have been studied extensively, long-term impacts on the cellular immune system remain to be analyzed. Here, we comprehensively characterized immunological changes in peripheral blood mononuclear cells in 49 COVID-19-convalescent individuals (CI) in comparison to 27 matched SARS-CoV-2-unexposed individuals (UI). Despite recovery from the disease for more than 2 months, CI showed significant decreases in frequencies of invariant NKT and NKT-like cells compared to UI. Concomitant with the decrease in NKT-like cells, an increase in the percentage of annexin V and 7-aminoactinomycin D (7-AAD) double-positive NKT-like cells was detected, suggesting that the reduction in NKT-like cells results from cell death months after recovery. Significant increases in regulatory T cell frequencies and TIM-3 expression on CD4 and CD8 T cells were also observed in CI, while the cytotoxic potential of T cells and NKT-like cells, defined by granzyme B (GzmB) expression, was significantly diminished. However, both CD4 and CD8 T cells of CI showed increased Ki67 expression and were fully able to proliferate and produce effector cytokines upon T cell receptor (TCR) stimulation. Collectively, we provide a comprehensive characterization of immune signatures in patients recovering from SARS-CoV-2 infection, suggesting that the cellular immune system of COVID-19 patients is still under a sustained influence even months after the recovery from disease.IMPORTANCE Wuhan was the very first city hit by SARS-CoV-2. Accordingly, the patients who experienced the longest phase of convalescence following COVID-19 reside here. This enabled us to investigate the "immunological scar" left by SARS-CoV-2 on cellular immunity after recovery from the disease. In this study, we characterized the long-term impact of SARS-CoV-2 infection on the immune system and provide a comprehensive picture of cellular immunity of a convalescent COVID-19 patient cohort with the longest recovery time. We revealed that the cellular immune system of COVID-19 patients is still under a sustained influence even months after the recovery from disease; in particular, a profound NKT cell impairment was found in the convalescent phase of COVID-19.

MMP2/MMP9-mediated CD100 shedding is crucial for inducing intrahepatic anti-HBV CD8 T cell responses and HBV clearance

BACKGROUND & AIMS

CD100 is constitutively expressed on T cells and can be cleaved from the cell surface by matrix metalloproteases (MMPs) to become soluble CD100 (sCD100). Both membrane-bound CD100 (mCD100) and sCD100 have important immune regulatory functions that promote immune cell activation and responses. This study investigated the expression and role of mCD100 and sCD100 in regulating antiviral immune responses during HBV infection.

METHODS

mCD100 expression on T cells, sCD100 levels in the serum, and MMP expression in the liver and serum were analysed in patients with chronic HBV (CHB) and in HBV-replicating mice. The ability of sCD100 to mediate antigen-presenting cell maturation, HBV-specific T cell activation, and HBV clearance were analysed in HBV-replicating mice and patients with CHB.

RESULTS

Patients with CHB had higher mCD100 expression on T cells and lower serum sCD100 levels compared with healthy controls. Therapeutic sCD100 treatment resulted in the activation of DCs and liver sinusoidal endothelial cells, enhanced HBV-specific CD8 T cell responses, and accelerated HBV clearance, whereas blockade of its receptor CD72 attenuated the intrahepatic anti-HBV CD8 T cell response. Together with MMP9, MMP2 mediated mCD100 shedding from the T cell surface. Patients with CHB had significantly lower serum MMP2 levels, which positively correlated with serum sCD100 levels, compared with healthy controls. Inhibition of MMP2/9 activity resulted in an attenuated anti-HBV T cell response and delayed HBV clearance in mice.

CONCLUSIONS

MMP2/9-mediated sCD100 release has an important role in regulating intrahepatic anti-HBV CD8 T cell responses, thus mediating subsequent viral clearance during HBV infection.

LAY SUMMARY

Chronic hepatitis B virus (HBV) infection is a major public health problem worldwide. The clearance of HBV relies largely on an effective T cell immune response, which usually becomes dysregulated in chronic HBV infection. Our study provides a new mechanism to elucidate HBV persistence and a new target for developing immunotherapy strategies in patients chronically infected with HBV.

A Single-Nucleotide Polymorphism Upstream of the HLA-C Locus Is Associated With an Anti-Hepatitis C Virus-Seronegative State in a High-Risk Exposed Cohort

In this study, we examined the impact of the rs9264942 single-nucleotide polymorphism, previously shown to be associated with human immunodeficiency virus infection status and HLA-C expression, on the hepatitis C virus status in 359 people who inject drugs (PWID). The linkage of rs9264942 alleles to HLA-C antigens assigned to different expression levels was confirmed. Multivariate analysis revealed the age (P = .003) and the rs9264942 genotype (P = .006) to be independent factors for the classification to the PWID groups. Our study showed that the presence of the rs9264942 C/C genotype was associated with persistent seronegativity.

[Specific components for integrative and flexible care models according to § 64b SGB V]

BACKGROUND

There is a need for a theoretical model for evaluating integrative and flexible care models according to § 64b of the Social Security Statutes Book V (SGB V).

MATERIAL AND METHODS

An iterative process of data collection and analysis has been executed according to grounded theory methodology.

RESULTS

A total of 11 specific components have been identified and shown to be robust and practicable and compatible with the data from the literature.

CONCLUSION

These components can be used for implementation, quality management and evaluation of projects for treatment models according to § 64b SGB V.

High efficacy of sofosbuvir/velpatasvir and impact of baseline resistance-associated substitutions in hepatitis C genotype 3 infection

BACKGROUND

Twelve weeks of the pangenotypic direct-acting antiviral (DAA) combination sofosbuvir/velpatasvir (SOF/VEL) was highly efficient in patients with hepatitis C virus (HCV) genotype 3 (GT3) infection in the ASTRAL-3 approval study. However, presence of resistance-associated substitutions (RASs) in the HCV nonstructural protein 5A (NS5A) was associated with lower treatment response.

AIM

To assess the efficacy and safety of SOF/VEL ± ribavirin (RBV) and the impact of NS5A RASs and RBV use on treatment outcome in HCV GT3 infection in a real-world setting.

METHODS

In this multicentre cohort study, GT3 patients from ten treatment centres across Germany were included. Sustained virological response was assessed 12 weeks after end-of-treatment (SVR12) in modified intention-to-treat (mITT) and per-protocol analysis (PP). NS5A RASs were tested by population-based sequencing.

RESULTS

A total of 293 GT3 patients were included. The median age was 48 years, 70% were male, 25.3% were cirrhotic, 9.2% were HCV/HIV co-infected and 21.8% were treatment-experienced, including 4.1% with DAA experience. Baseline NS5A RASs (Y93H, A30K, L31M) were detected in 11.2%. RBV was added in 5% of noncirrhotic and 58.9% of cirrhotic patients, respectively. SVR12 rates for SOF/VEL±RBV were 95.9% (mITT) and 99.5% (PP), respectively. Only 1 virological relapse occurred in a cirrhotic patient previously treated with SOF/RBV. No treatment-related major adverse events occurred.

CONCLUSION

Twelve weeks of SOL/VEL±RBV was safe and highly efficient in HCV GT3 across a diverse patient population. Baseline NS5A RASs were rarely observed and presence did not seem to impact SVR, regardless of the use of RBV.

Outcome of a hepatitis B vaccination program for clients of a drug consumption facility

BACKGROUND

Intravenous drug users (IDUs) are a risk group for hepatitis B. In Germany, the hepatitis B virus (HBV) vaccination rates in IDUs are low.

OBJECTIVES

In this study the implementation and success of HBV vaccination in a drug consumption facility (DCF) was evaluated.

STUDY DESIGN

Clients attending a DCF were asked regarding their HBV status. In case of no known HBV infection and no previous vaccination, clients interested in HBV vaccination were offered a HBV blood testing. HBV vaccination was administered to susceptible clients in months 0, 1, 6. Booster vaccinations were offered to clients without seroconversion (anti-HBs < 100 U/l).

RESULTS

193 out of 364 clients reported on a known HBV infection or immunity after vaccination. 95 (55.6%) out of 171 eligible clients underwent a HBV serology. According to HBV serology 31 (32.6%) out of 95 clients were not susceptible for vaccination (mainly due to an unknown HBV infection). 47 (73.4%) out of 64 clients susceptible were administered 3 vaccinations. 10 clients received at least one further vaccination. For those showing up for testing (36 out of 47 clients) the seroconversion rate was 69.4% (> 100 IU/l) and 83.3% (> 10 IU/l), respectively.

DISCUSSION

Only a minority of clients of a DCF was susceptible for HBV vaccination. 47 out of 64 (73.4%) susceptible clients underwent at least three administrations of the vaccine, mostly resulting in seroconversion. Even in IDUs attending a DCF, a clientele with unstable social and health conditions, HBV vaccination can be carried out successfully.

The CO dehydrogenase accessory protein CooT is a novel nickel-binding protein

In Rhodospirillum rubrum, maturation of Carbon Monoxide Dehydrogenase (CODH) requires three accessory proteins, CooC, CooT and CooJ, dedicated to nickel insertion into the active site, which is constituted by a distorted [NiFe₃S₄] cubane coordinated with a mononuclear Fe site. CooC is an ATPase proposed to provide the energy required for the maturation process, while CooJ is described as a metallochaperone with 16 histidines and 2 cysteines at the C-terminus, likely involved in metal binding and/or storage. Prior to the present study, no information was available on CooT at the molecular level. Here, the X-ray structure of RrCooT was obtained, which revealed that this protein is a homodimer featuring a fold that resembles an Sm-like domain, suggesting a role in RNA metabolism that was however not supported by experimental observations. Biochemical and biophysical evidence based on circular dichroism spectroscopy, light scattering, isothermal titration calorimetry and site-directed mutagenesis showed that RrCooT specifically binds a single Ni(ii) per dimer, with a dissociation constant of 9 nM, through the pair of Cys2, highly conserved residues, located at the dimer interface. Despite its role in the activation of RrCODH in vivo, CooT was thought to be a unique protein, found only in R. rubrum, with an unclear function. In this study, we extended the biological impact of CooT, establishing that this protein is a member of a novel Ni(ii)-binding protein family with 111 homologues, linked to anaerobic metabolism in bacteria and archaea, and in most cases to the presence of CODH.

TLR2 Expression in Peripheral CD4+ T Cells Promotes Th17 Response and Is Associated with Disease Aggravation of Hepatitis B Virus-Related Acute-On-Chronic Liver Failure

Th17 responses have been shown to play crucial roles in the pathogenesis of hepatitis B virus (HBV)-associated acute-on-chronic liver failure (ACLF). The mechanism underlying the enhanced Th17 responses in these patients remains largely unclear. Here we investigated toll-like receptors (TLRs) expression in peripheral T cells and their roles in Th17 cell differentiation and disease aggravation in ACLF patients. 18 healthy subjects (HS), 20 chronic HBV-infected (CHB) patients, and 26 ACLF patients were enrolled and examined for TLRs expression in peripheral blood mononuclear cells (PBMCs). The correlations of T cell TLR2 expression with the antigen non-specific Th17 responses and disease aggravation, as well as the Th17 response to TLR2 ligand stimulation were evaluated in ACLF patients. Compared to HS and CHB patients, ACLF patients showed a distinct TLRs expression pattern in PBMCs. Significantly increased TLR2 expression in T cells was observed in ACLF patients. The TLR2 expression in CD4+ T cells was correlated with the Th17 responses and the clinical markers for disease aggravation in ACLF patients. Moreover, TLR2 ligands stimulation promoted Th17 cell differentiation and response in PBMCs of ACLF patients. These findings implicate that TLR2 signaling plays critical roles in Th17 cell differentiation and disease aggravation of HBV-related ACLF.

Treatment of fulminant acute Hepatitis B with nucles(t)id analogues is safe and does not lead to secondary chronification of Hepatitis B

Background: Acute hepatitis B virus (HBV) infection is still a major cause of acute liver failure (ALF), necessitating a high rate of emergency liver transplantation (LTx). Acute infection is followed by high viral replication rates leading to hepatocyte death and, ultimately, ALF. The objective of treating HBV-induced ALF thus is to eliminate, or significantly suppress, HBV replication and therefore reduce cell death and support regeneration. Objective: In this retrospective study, we want to evaluate the timing, the safety, and the long-term virological outcome of this approach. Methods/results: In this study, we included 32 patients (16 female and 16 males; median age 39.5 years) with ALF due to hepatitis B, who were transferred to the university hospital Essen, Germany between January 2009 and December 2013. Before treatment, transaminases were highly elevated, bilirubin was increased, and elevated international normalized ratio (INR) revealed impaired liver function. HBV-DNA and HBsAg were positive. All 32 patients received oral antiviral treatment (3 lamivudine, 21 entecavir, and 8 tenofovir) between 1 day and 4 months after diagnosis of acute hepatitis B. One patient died, 2 were transplanted, one died shortly after LTx the other patient survived after LTx. These 3 patients received treatment in a state of advanced liver failure, and 1 patient 4 months after initial diagnosis of hepatitis B. Twenty-nine patients survived without LTx. Five patients were discharged without further follow-up. All 24 remaining patients became HBV-DNA negative in median of 100 days. Twenty-two patients were followed further, and all patients lost their HBsAg in median of 108 days. Sixteen of the 22 patients experienced a seroconversion to anti-HBs in median of 137 days. Four patients who were followed for 1 more year after HBsAg did not develop anti-HBs. None of the patients developed chronic hepatitis B. Conclusion: Immediate treatment of HBV-induced ALF with nucleos(t)id-analogues (NUCs) appears save and prevents LTx and death, and there is no indication for increased chronicity.

Nuclear receptors control pro-viral and antiviral metabolic responses to hepatitis C virus infection

Viruses lack the basic machinery needed to replicate and therefore must hijack the host's metabolism to propagate. Virus-induced metabolic changes have yet to be systematically studied in the context of host transcriptional regulation, and such studies shoul offer insight into host-pathogen metabolic interplay. In this work we identified hepatitis C virus (HCV)-responsive regulators by coupling system-wide metabolic-flux analysis with targeted perturbation of nuclear receptors in primary human hepatocytes. We found HCV-induced upregulation of glycolysis, ketogenesis and drug metabolism, with glycolysis controlled by activation of HNF4α, ketogenesis by PPARα and FXR, and drug metabolism by PXR. Pharmaceutical inhibition of HNF4α reversed HCV-induced glycolysis, blocking viral replication while increasing apoptosis in infected cells showing virus-induced dependence on glycolysis. In contrast, pharmaceutical inhibition of PPARα or FXR reversed HCV-induced ketogenesis but increased viral replication, demonstrating a novel host antiviral response. Our results show that virus-induced changes to a host's metabolism can be detrimental to its life cycle, thus revealing a biologically complex relationship between virus and host.

Adaptation of the hepatitis B virus core protein to CD8(+) T-cell selection pressure

Activation of hepatitis B virus (HBV)-specific CD8 T cells by therapeutic vaccination may promote sustained control of viral replication by clearance of covalently closed circular DNA from infected hepatocytes. However, little is known about the exact targets of the CD8 T-cell response and whether HBV reproducibly evades CD8 T-cell immune pressure by mutation. The aim of this study was to address if HBV reproducibly selects substitutions in CD8 T-cell epitopes that functionally act as immune escape mutations. The HBV core gene was amplified and sequenced from 148 patients with chronic HBV infection, and the human leukocyte antigen (HLA) class I genotype (A and B loci) was determined. Residues under selection pressure in the presence of particular HLA class I alleles were identified by a statistical approach utilizing the novel analysis package SeqFeatR. With this approach we identified nine residues in HBV core under selection pressure in the presence of 10 different HLA class I alleles. Additional immunological experiments confirmed that seven of the residues were located inside epitopes targeted by patients with chronic HBV infection carrying the relevant HLA class I allele. Consistent with viral escape, the selected substitutions reproducibly impaired recognition by HBV-specific CD8 T cells.

CONCLUSION

Viral sequence analysis allows identification of HLA class I-restricted epitopes under reproducible selection pressure in HBV core; the possibility of viral escape from CD8 T-cell immune pressure needs attention in the context of therapeutic vaccination against HBV.

Decades after recovery from hepatitis B and HBsAg clearance the CD8+ T cell response against HBV core is nearly undetectable

BACKGROUND & AIMS

CD8(+) T cells are an essential component of a successful immune response against hepatitis B virus (HBV). Patients who spontaneously clear HBsAg after acute HBV infection have a strong CD8(+) T cell immune response, predominantly directed against the HBV core protein (HBcAg). However, the fate and phenotype of HBcAg-specific CD8(+) T cells after immune control are unclear.

METHODS

The CD8(+) T cell immune response against HBV core was determined in 65 patients with chronic HBV infection, 16 patients after recovery from acute HBV infection, and four patients with acute HBV infection utilizing overlapping peptides and HLA class I/peptide-multimers.

RESULTS

Patients who had cleared HBsAg >30 years ago had significantly weaker CD8(+) T cell responses after antigen-specific expansion compared to patients who had cleared the virus <10 years ago and patients with HBeAg negative chronic infection and low viral load (<2000 IU/ml; p<0.01). Also directly ex vivo, patients who had cleared the HBsAg >30 years ago had less HBV-specific CD8(+) T cells compared to patients with HBeAg negative chronic infection (p=0.0025). In patients with acute HBV infection, the frequency of HBc-specific CD8(+) T cells continued to decline after clearance of HBV-DNA and HBsAg even at a time when ALT levels had already normalized (p=0.0313).

CONCLUSIONS

The frequency of HBcAg-specific CD8(+) T cells continuously declines after HBsAg clearance. In line with clinical observations, this suggests that humoral and not CD8(+) T cell immune responses mainly contribute to prevention of HBV reactivation decades after HBsAg clearance.

Evaluation of an integrated care program for schizophrenia: concept and study design

Concept and design of an independent scientific evaluation of different pathways of care for schizophrenia patients in Germany with respect to effectiveness and efficiency are presented. In this prospective, observational study, schizophrenia patients receiving an integrated care treatment, the intervention group (IG), are compared with patients under routine care conditions treated by the same physician (first control group, CG 1). A second control group (CG 2) of patients treated by office-based psychiatrists not participating in the integrated care program will be recruited and their data compared with the two other groups. The total amount of psychiatric hospital days after 12 months is defined as primary outcome parameter. Secondary outcome parameters comprise the frequency of psychiatric inpatient readmissions, severity of schizophrenia symptoms, remission rates and quality of life. Patients undergo assessments at baseline, month 6 and 12 using standardized and experimental questionnaires. Routine data of a regional German social health insurance fund complement information on included patients. Additionally, a cost-effectiveness and cost-utility analysis will be performed. Until now, 137 psychiatrists included 980 patients in the integrated care project in Lower Saxony, Germany, and 47 psychiatrists (IG and both CGs) are willing to participate in the independent evaluation. For the first time, a prospective observational controlled evaluation study of a countrywide integrated care project planning to recruit 500 schizophrenia patients has started using comprehensive assessments as well as routine data of a social health insurance fund.

KIR2DL3⁺NKG2A⁻ natural killer cells are associated with protection from productive hepatitis C virus infection in people who inject drugs

BACKGROUND & AIMS

Despite continuous high-risk behavior, a subgroup among people who inject drugs (PWID) remains seronegative for hepatitis C virus (HCV) suggesting that a state of "natural resistance" to HCV Infection may exist. Homozygosity for KIR2DL3 and its ligand HLA-C1 group alleles has been associated with control of HCV infection, however, the mechanism mediating this protective effect remained unclear.

METHODS

Peripheral NK cells from PWID (n=104) were phenotypically and functionally characterized by multicolor flow cytometry. Expression levels of the NK cell receptor ligands were analysed in liver biopsies and primary human hepatocytes.

RESULTS

HCV seronegative PWID (n=34) had increased levels of KIR2DL3(+)NKG2A(-) NK cells compared to healthy controls (n=10; p<0.001) and PWID with chronic (n=38; p<0.001) or resolved infection (n=37; p<0.001). There was an inverse correlation between the frequency of KIR2DL3(+) and NKG2A(+) NK cells (r=-0.53; p<0.0001). Importantly, expression of HLA-E, the ligand for NKG2A, was significantly upregulated in liver biopsies of HCV infected patients (n=51) compared to HBV infected patients (n=22; p<0.01) and correlated with HCV viral load (r=0.32; p<0.0029). In functional analyses KIR2DL3(-)NKG2A(+) NK cells but not KIR2DL3(+)NKG2A(-) NK cells were significantly inhibited by HLA-E ligation. Accordingly, interferon gamma secretion of NK cells from PWID with chronic infection but not from HCV seronegative PWID was significantly suppressed in the presence of HLA-E.

CONCLUSIONS

KIR2DL3(+)NKG2A(-) NK cells are not sensitive to HLA-E-mediated inhibition and may thereby control early HCV infection prior to seroconversion and result in an apparent state of "natural resistance" to HCV in PWID.

Genetic heterogeneity of hepatitis C virus cell entry receptors seems to have no influence on selection of virus variants

Background

No information is available on the possible influence of the genetic heterogeneity of major hepatitis C virus (HCV) cell receptors on selection of virus variants.

Findings

Anti-D globulin preparations contaminated with the HCV strain AD78 caused hepatitis C infection in more than 3000 women in East Germany in 1978. Analysis of the core to NS2 gene sequences of this strain in several globulin batches revealed the presence of three closely related but distinct virus variants of the same strain. Apparently even distribution of these three virus variants was observed in 91 patients infected with the AD78 strain. None of these patients was infected with more than one virus variant, suggesting a selection mechanism of a particular virus variant in each patient. To verify the hypothesis that heterogeneity of HCV cell receptors might influence the virus variant selection, single-nucleotide polymorphisms (SNPs) in low-density lipoprotein receptor (LDLR), occludin (OCLN), and scavenger receptor B1 (SCARB1) genes in AD patients were analyzed. No evident correlation between receptor polymorphisms and presence of a particular virus variant was noted.

Conclusion

SNPs of HCV cell entry receptors have no influence on virus selection in patients infected with an inoculum containing different virus variants.

[HCV reinfection after liver transplantation - management and first experiences with telaprevir-based triple therapy]

BACKGROUND AND OBJECTIVE

The management of hepatitis C virus (HCV) recurrence after liver transplantation (LTx) is a major challenge in patient care. For patients with HCV GT1, treatment standard with pegylated interferon (PEG-IFN) and ribavirin (RBV) has been augmented in 2011 by first generation protease inhibitors (PI), telaprevir (TVR) and boceprevir (BOC). We report our first experiences with TVR-based triple therapy in patients with GT1-reinfection of the graft.

PATIENTS AND METHOD

13 patients with histologically proven HCV GT1-reinfection of the graft received 12 weeks of PEG-IFN/RBV/TVR followed by 12 weeks of PEG-IFN/ RBV only. During the triple therapy phase immune suppression was tightly monitored, and the patients were also closely monitored for side effects.

RESULTS

The dosage of immunosuppressants had to be reduced significantly (TAC: 30-fold; CSA 3,5-fold). Stable levels were achieved by daily or over-daily dosing of a special size application of 0,1 mg tacrolimus (Tac) bid or a minimal dose of 10 mg cyclosporine (CSA) bid or qd, respectively. In all patients hematological side effects were observed, 65 % of which required RBV dose reduction, administration of erythropoietin or blood transfusions. Increase of kidney retention values requiring infusions occurred in 50 %. All side effects were reversible. There were no early discontinuations of therapy. An early viral response (EVR) with viral decline below limit of detection was noted at week 12 in 9/13 patients and at week 12 in further 3 patients.

CONCLUSION

Our preliminary results show high EVR response rates of TVR-based triple therapy in LTx patients with HCV-GT1 re-infection.

A patient with severe respiratory failure caused by novel human coronavirus

We report a case of a 45-year-old patient who developed severe acute respiratory distress syndrome accompanied by renal failure. An infection with a novel human coronavirus was confirmed and found to be the reason for rapidly progressive respiratory failure of our patient.

Assays for laboratory confirmation of novel human coronavirus (hCoV-EMC) infections

We present a rigorously validated and highly sensitive confirmatory real-time RT-PCR assay (1A assay) that can be used in combination with the previously reported upE assay. Two additional RT-PCR assays for sequencing are described, targeting the RdRp gene (RdRpSeq assay) and N gene (NSeq assay), where an insertion/deletion polymorphism might exist among different hCoV-EMC strains. Finally, a simplified and biologically safe protocol for detection of antibody response by immunofluorescence microscopy was developed using convalescent patient serum.

An empiric analysis of omaha system targets

Interface terminologies used in electronic health records must be re-evaluated and revised to reflect current health care practice and knowledge. To enable future revisions of the Omaha System Intervention Scheme, investigators evaluated formal semantic structure of target terms and concept duplication of problem and target terms. Using linguistic principles and qualitative analysis, five themes were found. A multidimensional formal semantic structure for the intervention target term was proposed. Concept duplication was examined for 16 problem-target matches. Clinical data enabled assessment of the validity of a proposed formal semantic structure and concept duplication. Recommendations are suggested for future development of the Omaha System Intervention Scheme.

[Bremen Risk Assessment Scale for General Psychiatry. Predicting violent behavior in mentally ill patients discharged from general psychiatry]

BACKGROUND

In order to identify psychiatric patients who have a higher risk of being aggressive towards others, a risk checklist, the "Bremen Risk Assessment Scale for General Psychiatry" (BRAS-GP) was developed. The results of the first trial are described in this article.

METHODS

In this prospective study all in-patients who were treated in the last quarter of 2006 were included. The BRAS-GP was applied on discharge to patients who were treated involuntarily. In a 1-year follow-up all patients who had been readmitted were analyzed to assess if any aggressive incident had occurred to confirm or refute the prognoses.

RESULTS

On evaluation of the readmissions data, we calculated sensitivity of 0.72 and specificity of 0.71 as well as an "area under the curve" of 0.74. Especially during the first months after discharge readmissions linked with aggressive behavior were observed.

CONCLUSION

The BRAS-GP is a useful prognostic instrument with high predictive validity. It can be easily applied in general psychiatric wards to help identify risk patients. After detecting risk patients special treatment strategies can then be offered.

Characterization of CD8+ T-cell response in acute and resolved hepatitis A virus infection

BACKGROUND & AIMS

In contrast to the infection with other hepatotropic viruses, hepatitis A virus (HAV) always causes acute self-limited hepatitis, although the role for virus-specific CD8 T cells in viral containment is unclear. Herein, we analyzed the T cell response in patients with acute hepatitis by utilizing a set of overlapping peptides and predicted HLA-A2 binders from the polyprotein.

METHODS

A set of 11 predicted peptides from the HAV polyprotein, identified as potential binders, were synthesized. Peripheral blood mononuclear cells (PBMCs) from patients were tested for IFNγ secretion after stimulation with these peptides and ex vivo with HLA-A2 tetramers. Phenotyping was carried out by staining with the activation marker CD38 and the memory marker CD127.

RESULTS

Eight out of 11 predicted HLA-A2 binders showed a high binding affinity and five of them were recognized by CD8+ T cells from patients with hepatitis A. There were significant differences in the magnitude of the responses to these five peptides. One was reproducibly immunodominant and the only one detectable ex vivo by tetramer staining of CD8+ T cells. These cells have an activated phenotype (CD38hi CD127lo) during acute infection. Three additional epitopes were identified in HLA-A2 negative patients, most likely representing epitopes restricted by other HLA-class I-alleles (HLA-A11, B35, B40).

CONCLUSIONS

Patients with acute hepatitis A have a strong multi-specific T cell response detected by ICS. With the tetramer carrying the dominant HLA-A2 epitope, HAV-specific and activated CD8+ T cells could be detected ex vivo. This first description of the HAV specific CTL-epitopes will allow future studies on strength, breadth, and kinetics of the T-cell response in hepatitis A.

Spontaneous control of HCV is associated with expression of HLA-B 57 and preservation of targeted epitopes

BACKGROUND & AIMS

HLA class I alleles are linked to spontaneous control of hepatitis C virus (HCV) and human immunodeficiency virus-1, but for HCV the roles of particular alleles and corresponding CD8(+) T-cell responses remain incompletely defined. We aimed to determine the correlations between these alleles and natural outcomes of HCV and determine associated key T-cell responses.

METHODS

In a cohort of HCV individuals, we determined HLA class I alleles, HCV outcomes, T-cell responses, and examined sequence data for mutational changes within key epitopes.

RESULTS

Carriage of HLA-B 57 was associated with a higher rate of viral clearance (risk ratio = 2.0; 95% confidence interval: 1.2-3.4), while HLA-B 08 was associated with a lower rate (risk ratio = 0.34; 95% confidence interval: 0.1-0.9]. Two HLA-B 57-restricted T-cell epitopes were targeted in spontaneous clearance; subjects with chronic viremia expressing HLA-B 57 harbored HCV strains with a high frequency of mutations in key residues. HLA-B 57-mediated escape was supported by diminished immune recognition of these variants and acute HCV infection revealing viral evolution toward less recognized variants. Analysis of a genotype 1b strain from a single-source HCV outbreak in which HLA-B 57 was not protective revealed sequence variations that interfere with immunogenicity, thereby preventing HLA-B 57-mediated immune pressure.

CONCLUSIONS

Our data indicate a role of HLA-B 57-restricted CD8(+) T-cell responses in mediating spontaneous clearance and evolution in HCV infection, and viral strains containing epitope variants that are less recognized abrogate the protective effects of HLA-B 57. The finding that HLA-B 57-mediated antiviral immunity is associated with control of both human immunodeficiency virus-1 and HCV suggests a common shared mechanism of a successful immune response against persistent viruses.

The resistance mutation R155K in the NS3/4A protease of hepatitis C virus also leads the virus to escape from HLA-A*68-restricted CD8 T cells

The NS3/4A serine protease of the hepatitis C virus (HCV) is one of the most attractive targets for specific antiviral agents. However, mutations conferring resistance may decrease the efficacy of these drugs. Although the level of resistance associated with specific mutations differs between different compounds, substitutions R155K and A156T reduce susceptibility to all protease inhibitors published so far. Interestingly, variants harboring the resistant mutation R155K were also detected as the predominant quasispecies in some treatment-naïve patients. Of note, key positions for resistance overlap with the HLA-A*68-restricted epitope HAVGIFRAAV(1175-1184). The aim of our study was to analyze the impact of protease inhibitor resistance mutations on the replication level and the antiviral CD8 T cell response against this HCV epitope. Our findings suggest that the R155K variant is associated with a relatively high replication level and with a substantial loss of cross-recognition by specific CD8 T cells targeting the epitope HAVGIFRAAV(1175-1184), providing a possible explanation for its existence in the absence of drug selection pressure.

Hepatitis C virus recombinants are rare even among intravenous drug users

Systematic studies of the circulation of hepatitis C virus (HCV) recombinants in different parts of the world have been initiated only recently, and no detailed information on this subject is available. The aim of the current investigation was to determine the frequency of HCV recombinants in intravenous drug users (IVDU) from two European countries. HCV RNA from serum samples was tested by RT-PCR with primers derived from the core and NS5B regions with subsequent sequencing and genotype assignment. The 118 samples from Germany (100%) and 45 out of 47 (96%) sera from Russia demonstrated concordant genotyping results. In the two genotype discrepant sera from Russia 2k/1b recombinants were identified. In order to test the hypothesis that the individuals from the IVDU group might be multiply exposed to various genotypes, 145 out of 165 genotyped serum samples, which were found to be positive for anti-NS4 antibodies, were serotyped with the Murex HCV serotyping kit that is based on detection of antibodies to type-specific peptides derived from the NS4 proteins of different HCV genotypes. Discrepancy in genotype and serotype attributions was observed in 11% cases. Retesting of 99 type 1a or 3a samples with a set of type- and subtype-specific primers revealed the presence of a mixed infection only in one case (1a/3a). Thus, the cases of the mixed infection with different HCV genotypes as well as the recombinant forms of HCV are very rare even in such a highly exposed group as IVDU.

Degree of cross-genotype reactivity of hepatitis C virus-specific CD8+ T cells directed against NS3

The inherent sequence diversity of the hepatitis C virus (HCV) with the existence of multiple genotypes that differ up to 20% at the amino acid level represents one of the major obstacles for immune control. Accordingly, immune control of a heterologous virus challenge, particularly across genotypes, is difficult to achieve; however, the overall role of genotype-specific sequence differences has not yet been defined at the epitope level. The aim of this study was to determine the role of genotype-specific sequence differences for the CD8+ T cell response against HCV. We analyzed a cohort of anti-HCV-positive injection drug users infected with HCV genotype 1 (n = 17) or genotype 3 (n = 22) or undetectable HCV-RNA (n = 14) with overlapping peptides covering consensus sequences of NS3 from both genotypes. Importantly, the majority of HCV-specific CD8 T cells were specific for one genotype only indicating that sequence differences between genotypes are relevant at the epitope level. Interestingly, T cells active against both genotypes were significantly more frequent in HCV-RNA-negative subjects. Of note, we identified five subjects with undetectable viremia and coexistence of two T cell populations-one for each genotype-suggesting immune control of two different genotypes.

CONCLUSION

We systematically analyzed the degree of cross-genotype reactivity of HCV-specific T cells and have shown that CD8 responses targeting different HCV genotypes can be primed in the same individual and that such responses potentially characterize a subgroup among injection drug users being protected from chronic HCV infection.

Temporal dynamics of a predominant protease inhibitor-resistance mutation in a treatment-naive, hepatitis C virus-infected individual

The dramatic antiviral activities of drugs that specifically inhibit hepatitis C virus replication can be tempered by baseline mutations that confer resistance. We describe the kinetics of an R155K mutation in hepatitis C virus (HCV) NS3 protease known to confer resistance to specific protease inhibitors in an individual coinfected with human immunodeficiency virus-1 and HCV. Longitudinal sequences revealed changes in the relative frequency with which this variant was observed independent of HCV replication levels, illustrating that this mutation coexists with wild-type strains in vivo in the absence of drugs. The persistence of drug-resistance mutations argues for baseline resistance genotyping at the time therapy is initiated to accurately predict the efficacy of treatment.

Naturally occurring dominant resistance mutations to hepatitis C virus protease and polymerase inhibitors in treatment-naïve patients

Resistance mutations to hepatitis C virus (HCV) nonstructural protein 3 (NS3) protease inhibitors in <1% of the viral quasispecies may still allow >1000-fold viral load reductions upon treatment, consistent with their reported reduced replicative fitness in vitro. Recently, however, an R155K protease mutation was reported as the dominant quasispecies in a treatment-naïve individual, raising concerns about possible full drug resistance. To investigate the prevalence of dominant resistance mutations against specifically targeted antiviral therapy for HCV (STAT-C) in the population, we analyzed HCV genome sequences from 507 treatment-naïve patients infected with HCV genotype 1 from the United States, Germany, and Switzerland. Phylogenetic sequence analysis and viral load data were used to identify the possible spread of replication-competent, drug-resistant viral strains in the population and to infer the consequences of these mutations upon viral replication in vivo. Mutations described to confer resistance to the protease inhibitors Telaprevir, BILN2061, ITMN-191, SCH6 and Boceprevir; the NS5B polymerase inhibitor AG-021541; and to the NS4A antagonist ACH-806 were observed mostly as sporadic, unrelated cases, at frequencies between 0.3% and 2.8% in the population, including two patients with possible multidrug resistance. Collectively, however, 8.6% of the patients infected with genotype 1a and 1.4% of those infected with genotype 1b carried at least one dominant resistance mutation. Viral loads were high in the majority of these patients, suggesting that drug-resistant viral strains might achieve replication levels comparable to nonresistant viruses in vivo.

CONCLUSION

Naturally occurring dominant STAT-C resistance mutations are common in treatment-naïve patients infected with HCV genotype 1. Their influence on treatment outcome should further be characterized to evaluate possible benefits of drug resistance testing for individual tailoring of drug combinations when treatment options are limited due to previous nonresponse to peginterferon and ribavirin.

Resistance mechanisms in HCV: from evolution to intervention

Recent advances in our understanding of the HCV life cycle and the functions of virally encoded proteins enabled the development of specifically targeted antiviral therapies for HCV, which directly inhibit HCV replication. Early clinical trials show great efficacy; however, from the first trials it became evident that, similar to HIV and HBV, selection of resistant variants will be problematic. Error-prone replication of HCV, resulting in a complex quasispecies population within each infected individual, enables rapid adaptation to changing environments. In this review, the evolutionary mechanisms involved in the selection process resulting in drug resistance are discussed. We give an overview of the resistance profiles to recently developed HCV protease and polymerase inhibitors and discuss potential implications for future treatment developments.

Sequence diversity of hepatitis C virus: implications for immune control and therapy

With approximately 3% of the world's population (170 million people) infected with the hepatitis C virus (HCV), the WHO has declared HCV a global health problem. Upon acute infection about 50%-80% of subjects develop chronic hepatitis with viral persistence being at risk to develop liver cirrhosis and hepatocellular carcinoma. One characteristic of HCV is its enormous sequence diversity, which represents a significant hurdle to the development of both effective vaccines as well as to novel therapeutic interventions. Due to a polymerase that lacks a proofreading function HCV presents with a high rate of evolution, which enables rapid adaptation to a new environment including an activated immune system upon acute infection. Similarly, novel drugs designed to specifically inhibit viral proteins will face the potential problem of rapid selection of drug resistance mutations. This review focuses on the sequence diversity of HCV, the driving forces of evolution and the impact on immune control and treatment response. An important feature of any therapeutic or prophylactic intervention will be an efficient attack of a structurally or functionally important region in the viral protein. The understanding of the driving forces, but also the limits of viral evolution, will be fundamental for the design of novel therapies.

Viral sequence evolution in acute hepatitis C virus infection

CD8(+)-T-cell responses play an important role in the containment and clearance of hepatitis C virus (HCV) infection, and an association between viral persistence and development of viral escape mutations has been postulated. While escape from CD8+ -T-cell responses has been identified as a major driving force for the evolution of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV), a broader characterization of this relationship is needed in HCV infection. To determine the extent, kinetics, and driving forces of HCV sequence evolution, we sequenced the entire HCV genome longitudinally in four subjects monitored for up to 30 months after acute infection. For two subjects the transmission sources were also available. Of 53 total non-envelope amino acid substitutions detected, a majority represented forward mutations away from the consensus sequence. In contrast to studies in HIV and SIV, however, only 11% of these were associated with detectable CD8+ T-cell responses. Interestingly, 19% of non-envelope mutations represented changes toward the consensus sequence, suggesting reversion in the absence of immune pressure upon transmission. Notably, the rate of evolution of forward and reverse mutations correlated with the conservation of each residue, which is indicative of structural constraints influencing the kinetics of viral evolution. Finally, the rate of sequence evolution was observed to decline over the course of infection, possibly reflective of diminishing selection pressure by dysfunctional CD8+ T cells. Taken together, these data provide insight into the extent to which HCV is capable of evading early CD8+ T-cell responses and support the hypothesis that dysfunction of CD8+ T cells may be associated with failure to resolve HCV infections.

Human leukocyte antigen-associated sequence polymorphisms in hepatitis C virus reveal reproducible immune responses and constraints on viral evolution

CD8(+) T cell responses play a key role in governing the outcome of hepatitis C virus (HCV) infection, and viral evolution enabling escape from these responses may contribute to the inability to resolve infection. To more comprehensively examine the extent of CD8 escape and adaptation of HCV to human leukocyte antigen (HLA) class I restricted immune pressures on a population level, we sequenced all non-structural proteins in a cohort of 70 chronic HCV genotype 1a-infected subjects (28 subjects with HCV monoinfection and 42 with HCV/human immunodeficiency virus [HIV] coinfection). Linking of sequence polymorphisms with HLA allele expression revealed numerous HLA-associated polymorphisms across the HCV proteome. Multiple associations resided within relatively conserved regions, highlighting attractive targets for vaccination. Additional mutations provided evidence of HLA-driven fixation of sequence polymorphisms, suggesting potential loss of some CD8 targets from the population. In a subgroup analysis of mono- and co-infected subjects some associations lost significance partly due to reduced power of the utilized statistics. A phylogenetic analysis of the data revealed the substantial influence of founder effects upon viral evolution and HLA associations, cautioning against simple statistical approaches to examine the influence of host genetics upon sequence evolution of highly variable pathogens.

CONCLUSION

These data provide insight into the frequency and reproducibility of viral escape from CD8(+) T cell responses in human HCV infection, and clarify the combined influence of multiple forces shaping the sequence diversity of HCV and other highly variable pathogens.

Immunologic evidence for lack of heterologous protection following resolution of HCV in patients with non-genotype 1 infection

Chronic hepatitis C virus (HCV) infection is typically characterized by a lack of virus-specific CD4(+) T-cell-proliferative responses, but strong responses have been described in a subset of persons with persistent viremia. One possible explanation for these responses is that they were primed by an earlier resolved infection and do not recognize the current circulating virus. We defined all targeted epitopes using overlapping peptides corresponding to a genotype 1a strain in 44 patients chronically infected with different HCV genotypes (GT). Surprisingly, more HCV-specific CD4(+) T-cell responses were detected in patients with chronic non-GT1 infection compared with patients with chronic GT1 infection (P = .017). Notably, we found serologic evidence of a previous exposure to GT1 in 4 patients with non-GT1 infection, and these persons also demonstrated significantly more responses than non-GT1 patients in whom genotype and HCV serotype were identical (P < .001). Comparison of recognition of GT1-specific peptides to peptides representing autologous virus revealed the absence of cross-recognition of the autologous circulating virus. These data indicate that persistent HCV infection can occur in the presence of an HCV-specific T-cell response primed against a heterologous HCV strain, and suggest that clearance of 1 GT does not necessarily protect against subsequent exposure to a second GT.

Characterization of full-length hepatitis C virus genotype 4 sequences

Over 85% of the world's nearly 170 million hepatitis C virus (HCV)-infected subjects exist in regions of Africa, Southeast Asia and Middle Eastern countries where genotypes 4-6 are very common. In particular, HCV genotype 4 is highly prevalent in Egypt with more than 19% of the population infected and chronic HCV representing one of the top five leading causes of death, due in part to ineffective interferon alpha treatment against this genotype. Despite this, very little work has been carried out to characterize the sequence diversity of genotype 4, which will be critical to the development of effective vaccines and antiviral therapies against this genotype. As a result of the paucity of sequence data available for HCV genotype 4, for which only one full genome sequence is currently available, we were interested in characterizing additional genotype 4 sequences and to provide reagents for amplification of this genotype. Here we describe seven unique HCV genotype 4a full genomes, in addition to a single genotype 4d genome, and characterize their sequence diversity in relation to other more closely characterized HCV genotypes.

Impaired hepatitis C virus-specific T cell responses and recurrent hepatitis C virus in HIV coinfection

BACKGROUND

Hepatitis C virus (HCV)-specific T cell responses are critical for spontaneous resolution of HCV viremia. Here we examined the effect of a lymphotropic virus, HIV-1, on the ability of coinfected patients to maintain spontaneous control of HCV infection.

METHODS AND FINDINGS

We measured T cell responsiveness by lymphoproliferation and interferon-gamma ELISPOT in a large cohort of HCV-infected individuals with and without HIV infection. Among 47 HCV/HIV-1-coinfected individuals, spontaneous control of HCV was associated with more frequent HCV-specific lymphoproliferative (LP) responses (35%) compared to coinfected persons who exhibited chronic HCV viremia (7%, p = 0.016), but less frequent compared to HCV controllers who were not HIV infected (86%, p = 0.003). Preservation of HCV-specific LP responses in coinfected individuals was associated with a higher nadir CD4 count (r(2) = 0.45, p < 0.001) and the presence and magnitude of the HCV-specific CD8(+) T cell interferon-gamma response (p = 0.0014). During long-term follow-up, recurrence of HCV viremia occurred in six of 25 coinfected individuals with prior control of HCV, but in 0 of 16 HIV-1-negative HCV controllers (p = 0.03, log rank test). In these six individuals with recurrent HCV viremia, the magnitude of HCV viremia following recurrence inversely correlated with the CD4 count at time of breakthrough (r = -0.94, p = 0.017).

CONCLUSIONS

These results indicate that HIV infection impairs the immune response to HCV-including in persons who have cleared HCV infection-and that HIV-1-infected individuals with spontaneous control of HCV remain at significant risk for a second episode of HCV viremia. These findings highlight the need for repeat viral RNA testing of apparent controllers of HCV infection in the setting of HIV-1 coinfection and provide a possible explanation for the higher rate of HCV persistence observed in this population.