Detection of host immune responses in acute phase sera of spontaneous resolution versus persistent hepatitis C virus infection

Prevalence and trends of hepatitis B and C virus biomarkers in Zimbabwe: comparative analyses of a nation's blood-donor surveillance data and meta-analyses of population studies

BACKGROUND

The disproportionate burden of viral hepatitis, particularly hepatitis B virus (HBV) is experienced by people living in low-resourced sub-Saharan Africa, where the estimated prevalence is 3-7 times the global average. Therefore to inform policy, we describe the seroprevalence and trends of hepatitis C (HCV) and HBV biomarkers: anti-HCV antibody and hepatitis B surface antigen (HBsAg), respectively, in Zimbabwe.

METHODS

We analysed data from 181,248 consecutive blood-donors, examined between January 2015 through December 2018. Additionally, we conducted a comprehensive literature review using PubMed and African Journals Online databases, meta-analysing selected papers from Zimbabwe, published between 1970 and 2020, that met specific criteria.

RESULTS

Overall age-standardized prevalence rate (ASPR) for anti-HCV was 8.67 (95%CI, 0.25-17.09) per 100,000, while that for HBsAg was 2.26 (95%, 1.89-2.63) per 1000 blood-donors, per year. Meta-analysis of 9 studies comprising 220,127 persons tested for anti-HCV revealed ASPR of 0.05% (95% 0%-0.19%) in blood-donors and 1.78% (95%CI, 0.01%-5.55%) in the general population, for an overall pooled ASPR of 0.44 (95%CI, 0.19%-0.76%). 21 studies comprising 291,784 persons tested for HBsAg revealed ASPR of 0.65% (95%CI, 0.31%-1.00%) in blood-donors and 4.31% (95%CI, 1.77%-6.50%) in the general population for an overall pooled ASPR of 4.02% (95%CI, 3.55%-4.48%), after HBV vaccine introduction. HBsAg prevalence was significantly higher before HBV vaccine introductions.

CONCLUSIONS

The prevalence of HBV is decreasing, consistent with the introduction of HBV vaccination, while HCV prevalence is increasing in Zimbabwe. This highlights the need for Improved blood-donor screening and more informative biomarker studies, particularly among repeat donors and children.

Biomarkers in Detection of Hepatitis C Virus Infection

The hepatitis C virus (HCV) infection affects 58 million people worldwide. In the United States, the incidence rate of acute hepatitis C has doubled since 2014; during 2021, this increased to 5% from 2020. Acute hepatitis C is defined by any symptom of acute viral hepatitis plus either jaundice or elevated serum alanine aminotransferase (ALT) activity with the detection of HCV RNA, the anti-HCV antibody, or hepatitis C virus antigen(s). However, most patients with acute infection are asymptomatic. In addition, ALT activity and HCV RNA levels can fluctuate, and a delayed detection of the anti-HCV antibody can occur among some immunocompromised persons with HCV infection. The detection of specific biomarkers can be of great value in the early detection of HCV infection at an asymptomatic stage. The high rate of HCV replication (which is approximately 1010 to 1012 virions per day) and the lack of proofreading by the viral RNA polymerase leads to enormous genetic diversity, creating a major challenge for the host immune response. This broad genetic diversity contributes to the likelihood of developing chronic infection, thus leading to the development of cirrhosis and liver cancer. Direct-acting antiviral (DAA) therapies for HCV infection are highly effective with a cure rate of up to 99%. At the same time, many patients with HCV infection are unaware of their infection status because of the mostly asymptomatic nature of hepatitis C, so they remain undiagnosed until the liver damage has advanced. Molecular mechanisms induced by HCV have been intensely investigated to find biomarkers for diagnosing the acute and chronic phases of the infection. However, there are no clinically verified biomarkers for patients with hepatitis C. In this review, we discuss the biomarkers that can differentiate acute from chronic hepatitis C, and we summarize the current state of the literature on the useful biomarkers that are detectable during acute and chronic HCV infection, liver fibrosis/cirrhosis, and hepatocellular carcinoma (HCC).

Clinical diagnosis of viral hepatitis: Current status and future strategies

Viral hepatitis (VH) is a significant public health issue with tremendous potential to aggravate into chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Recent decade has witnessed remarkable uprising in the drug development and effective treatment of VH. An upsurge is seen in identification of antiviral therapies with low rates of viral resistance, the improvement of Hepatitis B Virus (HBV) vaccination and the development of direct-acting antivirals for Hepatitis C Virus (HCV). But unfortunately, the "2030 worldwide eradication" objective of World Health Organization (WHO) is still unmet. It can be largely attributed to the deficit faced by the healthcare system concerning screening and diagnosis. A timely, accurate and comprehensive screening; encompassing maximum population coverage is essential to combat this disease. However, advancements in VH diagnostics remain inadequate and with a marginal use in routine practice. This paper deliberates upon the lacunae in traditional and prevailing diagnostic methodology of viral hepatitis, especially their inadequacy in meeting the unique situations prevailing low- and middle-income countries (LMIC).

The CCR5 and CXCR3 Pathways in Hepatitis C Virus Liver Transplanted Recipients Treated by a Direct Antiviral Agent Regimen: Informative Kinetics Profiles

The CC5 and CXC3 chemokines (CK) pathways are involved in the pathogenesis and outcome of several disease states, including chronic hepatitis C (CHC). The kinetics of Regulated upon Activation Normal T cell Expressed and Secreted (RANTES) (CCL5) and IP-10 (CXCL10) during direct-acting antivirals (DAA) treatment was retrospectively analyzed in 18 liver transplant recipients (LT-R) compared with 20 patients with CHC and 49 healthy controls (HC). CK levels were determined at baseline, week 4, end of treatment, 24 weeks post-treatment (sustained virological response [SVR]), and later-on during follow-up (FU), 12 and 24 months post-DAA. At baseline, median RANTES levels were higher in HC than in both LT-R (p > 0.01) and CHC (p > 0.01), whereas IP-10 levels were higher in LT-R and CHC than in HC (p > 0.05 and p = 0.01), respectively. Mean RANTES values increased during DAA therapy to peak at SVR and FU with significantly higher levels than at baseline in LT-R (p < 0.01) and in CHC, but only at FU (p < 0.003). A subsequent return to baseline or lower levels was observed at extended FU. On the contrary, IP-10 values showed a significant decrease from baseline to SVR and FU in both LT-R (p < 0.03) and CHC (p < 0.01). RANTES profiles during the first 4 weeks of DAA treatment showed an increase or decrease from baseline according to baseline RANTES levels. CCR5 genotyping in LT-R showed the presence of 1 homozygous Δ32/Δ32 and 2 heterozygous WT/Δ32 haplotypes with a prevalence of 5.5% and 11.1%, respectively. In conclusion, although IP-10 showed the expected kinetics, the CC5 pathway appears extensively altered during CHC infection: monitoring these patients may be indicated as they may be at risk of other infections or immune-mediated disorders.

African swine fever virus infection in Classical swine fever subclinically infected wild boars

BACKGROUND

Recently moderate-virulence classical swine fever virus (CSFV) strains have been proven capable of generating postnatal persistent infection (PI), defined by the maintenance of viremia and the inability to generate CSFV-specific immune responses in animals. These animals also showed a type I interferon blockade in the absence of clinical signs. In this study, we assessed the infection generated in 7-week-old CSFV PI wild boars after infection with the African swine fever virus (ASFV). The wild boars were divided in two groups and were infected with ASFV. Group A comprised boars who were CSFV PI in a subclinical form and Group B comprised pestivirus-free wild boars. Some relevant parameters related to CSFV replication and the immune response of CSFV PI animals were studied. Additionally, serum soluble factors such as IFN-α, TNF-α, IL-6, IL-10, IFN-γ and sCD163 were analysed before and after ASFV infection to assess their role in disease progression.

RESULTS

After ASFV infection, only the CSFV PI wild boars showed progressive acute haemorrhagic disease; however, the survival rates following ASFV infection was similar in both experimental groups. Notwithstanding, the CSFV RNA load of CSFV PI animals remained unaltered over the study; likewise, the ASFV DNA load detected after infection was similar between groups. Interestingly, systemic type I FN-α and IL-10 levels in sera were almost undetectable in CSFV PI animals, yet detectable in Group B, while detectable levels of IFN-γ were found in both groups. Finally, the flow cytometry analysis showed an increase in myelomonocytic cells (CD172a⁺) and a decrease in CD4⁺ T cells in the PBMCs from CSFV PI animals after ASFV infection.

CONCLUSIONS

Our results showed that the immune response plays a role in the progression of disease in CSFV subclinically infected wild boars after ASFV infection, and the immune response comprised the systemic type I interferon blockade. ASFV does not produce any interference with CSFV replication, or vice versa. ASFV infection could be a trigger factor for the disease progression in CSFV PI animals, as their survival after ASFV was similar to that of the pestivirus-free ASFV-infected group. This fact suggests a high resistance in CSFV PI animals even against a virus like ASFV; this may mean that there are relevant implications for CSF control in endemic countries. The diagnosis of ASFV and CSFV co-infection in endemic countries cannot be ruled out and need to be studied in greater depth.

Alanine aminotransferase, HCV RNA levels and pro-inflammatory and pro-fibrogenic cytokines/chemokines during acute hepatitis C virus infection

Background

This study assessed the association of alanine-aminotransferase (ALT) and hepatitis C virus (HCV) RNA levels with pro-inflammatory and pro-fibrogenic cytokines and chemokines during acute HCV infection to provide further insight into the potential HCV immunopathogenesis.

Methods

Participants in the ATAHC study, a prospective study of recent HCV infection, with detectable HCV RNA at the time of HCV detection were included. Plasma levels of 27 cytokines and chemokines were measured and their correlation with ALT and HCV RNA levels were assessed. Log₁₀ transformed cytokines and ALT values were used in the analysis.

Results

Among 117 individuals, the plasma levels of interferon-gamma inducible protein-10 (IP-10) and macrophage inflammatory protein-1beta (MIP-1β) were positively correlated with ALT levels (IP-10: r = 0.42, P < 0.001; MIP-1β: r = 0.29, P = 0.001) and HCV RNA levels (IP-10: rs = 0.44, P < 0.001; MIP-1β: rs = 0.43, P < 0.001). Using linear regression, after adjusting for sex, age, infection duration, symptomatic infection, HIV co-infection, interferon-lambda rs12979860 genotype, HCV genotype, and assay run, higher ALT levels (β = 0.20; 95 % CI: 0.07, 0.32; P = 0.002) and HCV RNA levels >400,000 IU/mL (vs. <8,500 IU/mL; β = 0.16; 95 % CI: 0.03, 0.28; P = 0.014) were independently associated with higher IP-10 levels. HCV RNA levels >400,000 IU/mL (vs. <8,500 IU/mL; β = 0.16; 95 % CI: 0.01, 0.31; P = 0.036) were associated with higher MIP-1β levels.

Conclusions

During acute HCV infection, high ALT and HCV RNA levels were associated with increased IP-10 levels, while high HCV RNA levels were also associated with increased MIP-1β levels. These data suggest that IP-10 and MIP-1β may have a role in HCV immuno-pathogenesis starting early in acute HCV infection.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-016-0482-x) contains supplementary material, which is available to authorized users.

Postnatal persistent infection with classical Swine Fever virus and its immunological implications

It is well established that trans-placental transmission of classical swine fever virus (CSFV) during mid-gestation can lead to persistently infected offspring. The aim of the present study was to evaluate the ability of CSFV to induce viral persistence upon early postnatal infection. Two litters of 10 piglets each were infected intranasally on the day of birth with low and moderate virulence CSFV isolates, respectively. During six weeks after postnatal infection, most of the piglets remained clinically healthy, despite persistent high virus titres in the serum. Importantly, these animals were unable to mount any detectable humoral and cellular immune response. At necropsy, the most prominent gross pathological lesion was a severe thymus atrophy. Four weeks after infection, PBMCs from the persistently infected seronegative piglets were unresponsive to both, specific CSFV and non-specific PHA stimulation in terms of IFN-γ-producing cells. These results suggested the development of a state of immunosuppression in these postnatally persistently infected pigs. However, IL-10 was undetectable in the sera of the persistently infected animals. Interestingly, CSFV-stimulated PBMCs from the persistently infected piglets produced IL-10. Nevertheless, despite the addition of the anti-IL-10 antibody in the PBMC culture from persistently infected piglets, the response of the IFN-γ producing cells was not restored. Therefore, other factors than IL-10 may be involved in the general suppression of the T-cell responses upon CSFV and mitogen activation. Interestingly, bone marrow immature granulocytes were increased and targeted by the virus in persistently infected piglets. Taken together, we provided the first data demonstrating the feasibility of CSFV in generating a postnatal persistent disease, which has not been shown for other members of the Pestivirus genus yet. Since serological methods are routinely used in CSFV surveillance, persistently infected pigs might go unnoticed. In addition to the epidemiological and economic significance of persistent CSFV infection, this model could be useful for understanding the mechanisms of viral persistence.

Suppressive effect of interleukin 10 on priming of naive hepatitis C virus-specific CD8+ T cells

Growing evidence suggests a role for the immunomodulatory cytokine interleukin-10 (IL-10) in hepatitis C virus (HCV)-specific CD8(+) T-cell failure. To address the possible role of IL-10 during priming, we performed in vitro priming experiments with naive HCV-specific CD8(+) T cells and autologous monocyte-derived dendritic cells in the absence or presence of IL-10. Our results showed that IL-10, when present during priming, significantly reduced the frequency of HCV-specific CD8(+) T cells after coculture; It was directly targeting CD8(+) T cells and led to impaired effector cell differentiation. These results may provide a possible mechanistic basis for the association between early IL-10 elevation, T-cell failure, and viral persistence.

Plasma interferon-gamma-inducible protein-10 levels are associated with early, but not sustained virological response during treatment of acute or early chronic HCV infection

Background

High plasma levels of interferon-gamma inducible protein-10 (IP-10) have been shown to be associated with impaired treatment response in chronic hepatitis C virus (HCV) infection. Whether IP-10 levels predict treatment in acute HCV infection is unknown.

Methods

Patients with acute or early chronic HCV infection from the Australian Trial in Acute Hepatitis C (ATAHC) cohort were evaluated. Baseline and on-treatment plasma IP-10 levels were measured by ELISA. IL28B genotype was determined by sequencing.

Results

Overall, 74 HCV mono-infected and 35 HIV/HCV co-infected patients were treated in ATAHC, of whom 89 were adherent to therapy and were included for analysis. IP-10 levels correlated with HCV RNA levels at baseline (r = 0.48, P<0.001) and during treatment. Baseline IP-10 levels were higher in patients who failed to achieve rapid virological response (RVR). Only one patient with a plasma IP-10 level >600 pg/mL achieved RVR. There was no association with IP-10 levels and early virological response (EVR) or sustained virological response (SVR).

Conclusions

Baseline IP-10 levels are associated with early viral kinetics but not ultimate treatment outcome in acute HCV infection. Given previous data showing that patients with high baseline IP-10 are unlikely to spontaneously clear acute HCV infection, they should be prioritized for early antiviral therapy.

Transfusion transmission of HCV, a long but successful road map to safety

Improved blood banking practices and the development and implementation of increasingly sensitive serological and nucleic acid amplification technology assays for screening donors for HCV over the past few decades have helped minimize the residual risk from transfusion transmitted HCV in the developed world. Furthermore, studies of transfusion transmitted infections and of donors identified as infected by routine screening have provided significant insights into HCV transmission, epidemiology and pathogenesis. However, transfusion transmission of HCV is still a significant route of infection in the developing world. Key preventive mechanisms to ensure safe blood include elimination of paid donors and development of national donor pools comprising volunteer repeat blood donors, combined with implementation of standardized and maximally sensitive screening assays for HCV. There is also a need to develop up-to-date data on HCV disease burden on a global scale, in part, derived from systematic screening of donors for HCV infection. We suggest the creation of blood donor databases and specimen repositories, both at national and international levels, to facilitate epidemiological surveillance and pathogenesis and treatment studies in the future.