Occult hepatitis C virus infection in the Middle East and Eastern Mediterranean countries: A systematic review and meta-analysis

Occult liver disease: A multinational perspective

Occult liver disease refers to the presence of unrecognized chronic liver disease and cirrhosis. Liver disease is currently the eleventh cause of death globally, representing 4% of all deaths in the world. Alcohol consumption is the leading cause of cirrhosis globally, accounting for approximately 60% of cases. The estimated global prevalence of non-alcoholic fatty liver disease (NAFLD) is 32.4% and has been steadily increasing over the last years. Viral hepatitis B and C accounted for 1.3 million deaths in 2020. Several studies in populations at high risk of chronic liver disease (elevated liver enzymes, type 2 diabetes, excessive alcohol consumption) have found an elevated prevalence of occult liver disease. Attempts should be made to assess the prevalence of occult liver disease in Latin America, a region with one of the highest rates of metabolic diseases and excessive alcohol consumption. Screening for NAFLD in high-risk subjects and screening for excessive drinking and alcohol use disorders at every level of medical care is relevant. Efforts should also focus on the early treatment of occult liver disease to try to reduce liver disease burden and, in the case of occult viral hepatitis infection, prevent further spreading.

Molecular Analysis and Ex Vivo Infectivity of Seronegative Occult Hepatitis C Virus: A Study in Single Haemodialysis Centre

Background

In occult hepatitis C virus infection (OCI), hepatitis C virus ribonucleic acid (HCV RNA) is detectable in peripheral blood mononuclear cells (PBMCs) but is not evident in serum or plasma. Understanding of OCI in patients with seronegative anti-HCV antibodies is limited.

Methods

In this study, six HCV isolates from haemodialysis (HD) patients with seronegative OCI were identified by molecular assays and phylogenetic analysis. The virus infectivity was assessed ex vivo using a primary naïve PBMC culture system. HCV isolates obtained from the PBMCs of 10 patients with chronic HCV infection (CCI) were characterised concurrently and used as positive controls in the cell culture.

Results

Sequence analysis of the 5' untranslated region (UTR) and non-structural 5B (NS5B) region revealed that HCV genotype 3 was the most prevalent virus type in both the OCI and CCI groups. One of the occult HCV isolates was identified as a mixed type. The mean viral load (log10 RNA copies/106 cells) in the PBMC samples of the OCI group (M = 3.4, SD = 0.7) was lower than that of the CCI group (M = 4.6, SD = 1.7). Upon culture, de novo OCI-HCV replicates were detected in five out of six naïve PBMC cultures. Analysis of the replicates showed a single guanine addition in the domain III of 5'-UTR but the overall molecular structure was retained.

Conclusion

Seronegative OCI is an active form of infection that replicates at a low level in PBMCs. Seronegative OCI may share the same route of transmission as CCI. The retained viral competency may have an implication for its persistence.

Unraveling IL-17 and IL-22 role in occult hepatitis C versus chronic hepatitis C virus infection

BACKGROUND

Cytokines play a crucial role in regulating the function of the immune system by controlling the production, differentiation, and activity of immune cells. Occult hepatitis C virus (OHCV) infection can lead to liver damage, including cirrhosis and hepatocellular carcinoma. This study investigates the immunopathogenic impact of the cytokines IL-17 and IL-22 in OHCV infection compared to chronic hepatitis C (CHC) infection.

METHODS

We studied three groups of patients: 35 with OHCV, 100 untreated patients with CHC, and 30 healthy control subjects. All subjects underwent physical examination and biochemical testing. We used the sandwich enzyme-linked immunosorbent assay method to measure serum IL-17 and IL-22 levels in all groups.

RESULTS

Compared to the occult and control groups, the CHC group had significantly higher serum IL-17 levels (p < 0.001). The occult group also had higher serum IL-17 levels compared to the control group (p < 0.0001). There were no significant differences in IL-22 levels across the research groups. In the OHCV group, individuals with moderate inflammation (A2-A3) had significantly higher serum IL-17 levels than those with minimal inflammation (A0-A1), while in the CHC group, this difference was not statistically significant (p = 0.601). Neither the occult nor the CHC groups showed a correlation between serum IL-22 and inflammatory activity. There was no significant correlation between the levels of IL-17 or IL-22 and the stage of fibrosis/cirrhosis in either group. ROC curves were calculated for serum IL-17 and IL-22 levels and occult HCV infection, with cut-off values set at ≤ 32.1 pg/ml and < 14.3 pg/ml for IL-17 and IL-22, respectively. The AUROC (95%CI) was significantly higher for IL-17 than IL-22 (0.829 (0.732-0.902) vs. 0.504 (0.393-0.614), p < 0.001), suggesting that IL-17 has a stronger correlation with infection risk than IL-22.

CONCLUSION

This study suggests that IL-17 may be involved in the immunopathogenesis of OHCV infection, especially in patients with moderate inflammation.

Occult hepatitis C virus infection in hemodialysis patients who achieved a sustained virological response to directly acting antiviral drugs: is it a concern?

PURPOSE

Hepatitis C virus infection is a major health problem in hemodialysis patients. Occult HCV infection is defined as the presence of HCV-RNA in hepatocytes or peripheral blood mononuclear cells without the detection of HCV-RNA in the serum. We aimed to evaluate the prevalence and predictors of occult HCV infection among hemodialysis patients after treatment with direct-acting antiviral agents.

METHODS

This research is a cross-sectional study that included 60 HCV patients maintained on regular HD patients who achieved 24 weeks of sustained virological response after treatment with direct-acting antiviral agents. Real-time PCR was performed to detect HCV-RNA in peripheral blood mononuclear cells.

RESULTS

HCV-RNA was detected in peripheral blood mononuclear cells of three patients (5%). Occult HCV infection cases were treated by Interferon/ribavirin before direct-acting antiviral agents and two of them had raised pre-treatment alanine aminotransferase levels. Logistic regression analyses revealed that high pre-treatment viral load and raised pre-treatment alanine aminotransferase were associated with an increased risk of occult HCV infection with p value of 0.041 and 0.029, respectively.

CONCLUSIONS

Occult HCV infection in hemodialysis patients who achieved sustained virological response after treatment with direct-acting antiviral agents may occur, and this may necessitate dual testing for HCV in both serum and peripheral blood mononuclear cells to ensure viral clearance.

CLINICAL TRIALS REGISTRATION

ClinicalTrials.gov NCT04719338.

Characterization of the Human Blood Virome in Iranian Multiple Transfused Patients

Blood transfusion safety is an essential element of public health. Current blood screening strategies rely on targeted techniques that could miss unknown or unexpected pathogens. Recent studies have demonstrated the presence of a viral community (virobiota/virome) in the blood of healthy individuals. Here, we characterized the blood virome in patients frequently exposed to blood transfusion by using Illumina metagenomic sequencing. The virome of these patients was compared to viruses present in healthy blood donors. A total number of 155 beta-thalassemia, 149 hemodialysis, and 100 healthy blood donors were pooled with five samples per pool. Members of the Anelloviridae and Flaviviridae family were most frequently observed. Interestingly, samples of healthy blood donors harbored traces of potentially pathogenic viruses, including adeno-, rota-, and Merkel cell polyomavirus. Viruses of the Anelloviridae family were most abundant in the blood of hemodialysis patients and displayed a higher anellovirus richness. Pegiviruses (Flaviviridae) were only observed in patient populations. An overall trend of higher eukaryotic read abundance in both patient groups was observed. This might be associated with increased exposure through blood transfusion. Overall, the findings in this study demonstrated the presence of various viruses in the blood of Iranian multiple-transfused patients and healthy blood donors.

Occult hepatitis C infection identified in injection drug users with direct antiviral agents therapy and spontaneous resolution of hepatitis C virus infection

BACKGROUND

Occult hepatitis C infection (OCI) is characterized by the detection of hepatitis C virus (HCV) RNA in hepatocytes and in peripheral blood mononuclear cells (PBMCs) without detection in serum. We aimed to evaluate OCI in drug and no drug users who achieved sustained virological response (SVR) after therapy with direct-acting antivirals (DAAs) and with HCV spontaneous resolution.

METHODS

Twenty-four patients in the AVP group (who achieved a SVR after DAAs therapy), 13 in the NAVP group (with HCV spontaneous resolution) and 7 HCV-RNA positive patients (CPP, control positive group) were included in the study. HCV/OCI-RNA was screened in serum and PBMCs samples of the patients by ddPCR for OCI patients' identification. Plasma and red blood cells (RBCs) samples of the patients were also evaluated for HCV/OCI-RNA detection by ddPCR.

RESULTS

OCI was presented in injection drug users (IDUs) in the AVP (20.8%) and NAVP (23.1%) groups by ddPCR with a higher statistically significant percentage detected in RBCs samples of the patients in the AVP group comparatively to NAVP (p<0.01) and CPP (p < 0.05) groups.

CONCLUSION

OCI was identified in IDUs patients of the AVP and NAVP groups by ddPCR. These results suggest that OCI patients in the AVP group might not be entirely cured, and that OCI patients in the NAVP group were not identified at clinical evaluation time when just serum samples were analysed. A higher percentage of HCV/OCI-RNA was detected in RBCs samples. Overall results recommends that HCV/OCI identification in patients with DAAs therapy and spontaneous resolution of HCV infection should be studied more accurately in future and in larger patient groups if possible. Additionally, suggest also PBMCs and RBCs samples as predictors for HCV/OCI diagnosis and management.

Epidemiology of occult hepatitis B and C in Africa: A systematic review and meta-analysis

BACKGROUND

Occult hepatitis B (OBI) and C (OCI) infections lead to hepatic crises including cases of liver cirrhosis and even hepatocellular carcinoma (HCC). OBI and OCI also pose a significant problem of their transmissibility. This study aimed to assess the overall prevalence of OBI and OCI in the African continent, a region highly endemic for classical hepatitis B and C viruses.

METHODS

For this systematic review and meta-analysis, we searched: PubMed, Web of Science, African Journal Online and African Index Medicus for published studies on the prevalence of OBI and OCI in Africa. Study selection and data extraction were performed by at least two independent investigators. Heterogeneity (I²) was assessed using the χ² test on the Cochran Q statistic and H parameters. Sources of heterogeneity were explored by subgroup analyses. This study was registered in PROSPERO, with reference number CRD42021252772.

RESULTS

We obtained 157 prevalence data for this meta-analysis, from 134 studies for OBI prevalence; 23 studies on OCI prevalence, and a single study on the OBI case fatality rate. The overall estimate for the prevalence of OBI was 14.8% [95% CI = 12.2-17.7] among 18579 participants. The prevalence of seronegative OBI and seropositive OBI was 7.4% [95% CI = 3.8-11.8] and 20.0% [95% CI = 15.3-25.1] respectively. The overall estimate for the prevalence of OCI was 10.7% [95% CI = 6.6-15.4] among 2865 participants. The pooled prevalence of seronegative OCI was estimated at 10.7% [95%CI = 4.8-18.3] and that of seropositive OCI at 14.4% [95%CI = 5.2-22.1]. In Sub-group analysis, patients with malignancies, chronic hepatitis C, and hemodialysis had a higher OCI prevalence. While those with malignancies, liver disorders, and HIV positive registered highest OBI prevalence.

CONCLUSION

This review shows a high prevalence of OBI and OCI in Africa, with variable prevalence between countries and population groups.

Global prevalence of occult hepatitis C virus: A systematic review and meta-analysis

BACKGROUND

Occult hepatitis C infection (OCI) is characterized by the presence of hepatitis C virus (HCV) RNA in the liver, peripheral blood mononuclear cells (PBMC) and/or ultracentrifuged serum in the absence of detectable HCV-RNA in serum. OCI has been described in several categories of populations including hemodialysis patients, patients with a sustained virological response, immunocompromised individuals, patients with abnormal hepatic function, and apparently healthy subjects.

AIM

To highlight the global prevalence of OCI.

METHODS

We performed a systematic and comprehensive literature search in the following 4 electronic databases PubMed, EMBASE, Global Index Medicus, and Web of Science up to 6th May 2021 to retrieve relevant studies published in the field. Included studies were unrestricted population categories with known RNA status in serum, PBMC, liver tissue and/or ultracentrifuged serum. Data were extracted independently by each author and the Hoy et al tool was used to assess the quality of the included studies. We used the random-effect meta-analysis model to estimate the proportions of OCI and their 95% confidence intervals (95%CI). The Cochran's Q-test and the I² test statistics were used to assess heterogeneity between studies. Funnel plot and Egger test were used to examine publication bias. R software version 4.1.0 was used for all analyses.

RESULTS

The electronic search resulted in 3950 articles. We obtained 102 prevalence data from 85 included studies. The pooled prevalence of seronegative OCI was estimated to be 9.61% (95%CI: 6.84-12.73) with substantial heterogeneity [I² = 94.7% (95%CI: 93.8%-95.4%), P < 0.0001]. Seropositive OCI prevalence was estimated to be 13.39% (95%CI: 7.85-19.99) with substantial heterogeneity [I² = 93.0% (90.8%-94.7%)]. Higher seronegative OCI prevalence was found in Southern Europe and Northern Africa, and in patients with abnormal liver function, hematological disorders, and kidney diseases. Higher seropositive OCI prevalence was found in Southern Europe, Northern America, and Northern Africa.

CONCLUSION

In conclusion, in the present study, it appears that the burden of OCI is high and variable across the different regions and population categories. Further studies on OCI are needed to assess the transmissibility, clinical significance, long-term outcome, and need for treatment.

Occult Infection with Hepatitis C Virus: Looking for Clear-Cut Boundaries and Methodological Consensus

The sustained virologic response and elimination of HCV is widely viewed as a true cure of chronic hepatitis C as it associates with amelioration of histological liver damage and improved clinical outcomes. Therefore, the existence and clinical burden of occult HCV infection (OCI) has been a controversial issue for many years. In this review, we summarize recently published data that adds new information on the molecular and clinical background of OCI and its epidemiological significance. We also identify and discuss the most important methodological pitfalls, which can be a source of inconsistency between studies. Data that have accumulated so far, strongly support the existence of extrahepatic HCV replication in individuals negative for serum HCV-RNA by conventional clinical tests. OCI emerges as a condition where the immune system is unable to fully resolve infection but it is continuously stimulated by low levels of HCV antigens, leading to progression of liver pathology and extrahepatic HCV-related complications. Moreover, the development of monitoring strategies or management guidelines for OCI is still hampered by the lack of clear definition and the confusion regarding its clinical significance. Careful study design and the introduction of uniform protocols for the detection of low-level HCV-RNA are crucial for obtaining reliable data on OCI.