Hepatitis C virus and blood transfusion: past and present risks

Host-targeting antivirals for chronic viral infections of the liver

Infection with one or several of the five known hepatitis viruses is a leading cause of liver disease and poses a high risk of developing hepatocellular carcinoma upon chronic infection. Chronicity is primarily caused by hepatitis B virus (HBV) and hepatitis C virus (HCV) and poses a significant health burden worldwide. Co-infection of chronic HBV infected patients with hepatitis D virus (HDV) is less common but is marked as the most severe form of chronic viral hepatitis. Hepatitis A virus (HAV) and hepatitis E virus (HEV) primarily cause self-limiting acute hepatitis. However, studies have also reported chronic progression of HEV disease in immunocompromised patients. While considerable progress has been made in the treatment of HCV and HBV through the development of direct-acting antivirals (DAAs), challenges including drug resistance, incomplete viral suppression resulting in failure to achieve clearance and the lack of effective treatment options for HDV and HEV remain. Host-targeting antivirals (HTAs) have emerged as a promising alternative approach to DAAs and aim to disrupt virus-host interactions by modulating host cell pathways that are hijacked during the viral replication cycle. The aim of this review is to provide a comprehensive overview about the major milestones in research and development of HTAs for chronic HBV/HDV and HCV infections. It also summarizes the current state of knowledge on promising host-targeting therapeutic options against HEV infection.

Chronic liver disease after allogeneic hematopoietic cell transplantation

BACKGROUND AIMS

There are few descriptions of the epidemiology of chronic liver disease (CLD) after allogeneic hematopoietic stem cell transplantation (allo-HCT). Among those transplanted before 2000, viral hepatitis was the dominant cause of CLD. Recently, the prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD, previously known as nonalcoholic fatty liver disease) is increasing in the general population. In addition, survivors of allo-HCT are known to be at increased risk of metabolic syndrome. We set out to describe the epidemiology of CLD in a modern cohort of allo-HCT recipients. We hypothesized that MASLD would be the most common cause of CLD in the cohort.

METHODS

We undertook a retrospective cohort and nested case-control study of 2-year survivors of allo-HCT in Alberta transplanted between 2008 and 2018.

RESULTS

Among 392 2-year survivors of allo-HCT between 2008 and 2018, the prevalence of CLD was 41.8% and MASLD was identified in 56% of those with CLD, followed by iron overload in 47% of those with CLD. The prevalence of MASLD among the entire cohort was 46%. Although most patients developed CLD before 2 years post-transplant, there was a 13% cumulative incidence of new CLD after 2 years posttransplant. Grade 2-4 acute graft-versus-host disease and/or moderate-to-severe chronic graft-versus-host disease and pretransplant CLD were strongly associated with CLD. In the case-control study examining the association between cardiovascular risk factors and CLD, type 2 diabetes was associated with CLD. Cirrhosis developed in 1.5% of survivors, and MASLD was an underlying etiology in one half of these cases. There was no difference in overall survival and non-relapse mortality between those who did and did not develop CLD.

CONCLUSIONS

MASLD is the main cause of CLD in recent long-term survivors of allo-HCT and may be associated with post-transplant corticosteroid exposure and type 2 diabetes. We note a shift in the underlying etiology of CLD post-HCT: previous studies describe viral hepatitis as the most common cause of CLD. The high prevalence of MASLD in allo-HCT recipients has important implications for survivorship care.

Contemporary Insights into Hepatitis C Virus: A Comprehensive Review

Hepatitis C virus (HCV) remains a significant global health challenge. Approximately 50 million people were living with chronic hepatitis C based on the World Health Organization as of 2024, contributing extensively to global morbidity and mortality. The advent and approval of several direct-acting antiviral (DAA) regimens significantly improved HCV treatment, offering potentially high rates of cure for chronic hepatitis C. However, the promising aim of eventual HCV eradication remains challenging. Key challenges include the variability in DAA access across different regions, slightly variable response rates to DAAs across diverse patient populations and HCV genotypes/subtypes, and the emergence of resistance-associated substitutions (RASs), potentially conferring resistance to DAAs. Therefore, periodic reassessment of current HCV knowledge is needed. An up-to-date review on HCV is also necessitated based on the observed shifts in HCV epidemiological trends, continuous development and approval of therapeutic strategies, and changes in public health policies. Thus, the current comprehensive review aimed to integrate the latest knowledge on the epidemiology, pathophysiology, diagnostic approaches, treatment options and preventive strategies for HCV, with a particular focus on the current challenges associated with RASs and ongoing efforts in vaccine development. This review sought to provide healthcare professionals, researchers, and policymakers with the necessary insights to address the HCV burden more effectively. We aimed to highlight the progress made in managing and preventing HCV infection and to highlight the persistent barriers challenging the prevention of HCV infection. The overarching goal was to align with global health objectives towards reducing the burden of chronic hepatitis, aiming for its eventual elimination as a public health threat by 2030.

Transfusion-transmitted infections

The risk of transfusion-transmitted infection (TTI) has always existed because transfused blood products are biological materials derived from humans. To prevent TTIs, screening strategies have been developed for various infectious diseases, such as hepatitis B virus, hepatitis C virus, and human immunodeficiency virus, contributing significantly to reducing TTI globally. Nevertheless, septic transfusion reactions (STRs) due to bacterial contamination remain an unresolved issue. Various infectious diseases can be transmitted through blood products, and preventive and selective screening strategies have been applied across different regions. Although multiple strategies, including culture-based and rapid detection kit-based methods, have been introduced to overcome STRs, complete prevention has not yet been achieved. Recently, pathogen inactivation methods have been developed to eliminate non-specific organisms rather than screening specific organisms. This approach is anticipated to contribute significantly to diminishing the risk of TTIs in the future.

How Possible Is the Elimination of Viral Hepatitis? An Analysis Based on the Global Burden of Disease from Hepatitis B and C, 1990-2019

This study assesses the feasibility of hepatitis B (HBV) and C (HCV) elimination using an analysis of trends of epidemiology data (1990-2019) from the Global Burden of Disease Study. Joinpoint regression analysis was used to identify significantly changing points in the trends of Age-standardized Prevalence Rates (ASPR) and Age-standardized Mortality Rates (ASMR) and to estimate the annual percentage changes (APC) and the average annual percentage changes (AAPC) for the period. The Sociodemographic Index (SDI) was used to analyze trends between countries. The total percentage change of the ASPR (2019/1990) was -31.4% and -12.8% for HBV and HCV worldwide, respectively; the rate ratio (HBV/HCV) was 2.5. Mortality had decreased for HBV but not for HCV. The total percentage change for the ASMR (2019/1990) was -26.7% and 10.0% for HBV and HCV, respectively. While the ASMR of HBV decreased, HCV increased during this period. The percentage change in ASMR of HBV was highest in countries with high-middle SDI and lowest in countries with high SDI. For HCV, the percentage change in ASMR was highest in countries with high SDI (increase), and only in countries with low SDI did it decrease. The global HBV and HCV rates have fallen with different AAPCs associated with the SDI. Despite the advances, there is still a long way to go to achieve the 2030 elimination goals. An important challenge is related to finding a way to speed up the yearly rate at which the decline is happening.

Risk of Hepatocellular Carcinoma After Spontaneous Clearance of Hepatitis C Virus and in Noncirrhosis Chronic Hepatitis C Patients With Sustained Virological Response: A Systematic Review

In a hepatitis C virus (HCV)-controlled human infection model (CHIM), healthy volunteers are inoculated with HCV and then treated. Residual hepatocellular carcinoma (HCC) risk after viral clearance is an important consideration when evaluating the CHIM. We estimate HCC risk in spontaneously cleared HCV and in noncirrhosis after sustained virological response (SVR) to HCV treatment in a systematic review and using data from 3 cohorts: German anti-D, Taiwan, and US Veterans Affairs (VA). For noncirrhosis SVR, the overall HCC rate is 0.33 per 100 patient-years in meta-analysis. HCC rates for the German, Taiwan, and US Veterans Affairs cohorts are 0, 0.14, and 0.02 per 100 patient-years, respectively. Past hepatitis B virus exposure was not accounted for in the Taiwan cohort, while VA patients were likely tested based on liver disease/risk factors, which may confound HCC outcomes. The German cohort with no HCC after 44 years is most comparable to the CHIM participants. Although it is difficult to precisely estimate HCC risk from an HCV CHIM, the data suggest the risk to be very low or negligible.

Hepatitis C virus screening reactive among blood donors in mainland C hina: A systematic review and meta‐analysis

BACKGROUND

Hepatitis C virus (HCV) can be transmitted by blood transfusion. The aim of this meta-analysis is to estimate the anti-HCV reactive rate and to define the demographic characteristics of blood donors who have potential threats to blood safety in mainland China for nearly 30 years, in order to provide a safe reference for blood transfusion and corresponding guidance for policymakers to increase blood safety.

MATERIALS AND METHODS

Literature reporting the anti-HCV screening reactive rate in Chinese blood donors was identified by systematic searching of four electronic databases from 1991 to 2017. The Preferred Reporting of Items for Systematic Reviews and Meta-Analyses guidelines were strictly followed, and data manipulation and statistical analysis were performed by Stata 15.0.

RESULTS

Our results showed that the post-donation anti-HCV reactive rate was 0.53% (95% confidence interval [CI], 0.51%-0.55%) with a significant variation from 1.58% (95% CI, 1.13%-2.03%) before 1998 to 0.51% (95% CI, 0.48%-0.53%) after 1998 when the Blood Donation Law was implemented in China. In addition, anti-HCV screening reactive rate for family or replacement donors was significantly higher than that in individual voluntary blood donors.

CONCLUSION

Our results indicated that blood centres in China should convert more eligible first-time donors into repeat donors and turn the 'real family or replacement donors' into individual voluntary blood donors to reduce the risk of transfusion-transmitted HCV. In the meantime, large surveys should be carried out among volunteer donors from high-risk populations.

Hepatitis C virus genotype 1 and 2 recombinant genomes and the phylogeographic history of the 2k/1b lineage

Recombination is an important driver of genetic diversity, though it is relatively uncommon in hepatitis C virus (HCV). Recent investigation of sequence data acquired from HCV clinical trials produced twenty-one full-genome recombinant viruses belonging to three putative inter-subtype forms 2b/1a, 2b/1b, and 2k/1b. The 2k/1b chimera is the only known HCV circulating recombinant form (CRF), provoking interest in its genetic structure and origin. Discovered in Russia in 1999, 2k/1b cases have since been detected throughout the former Soviet Union, Western Europe, and North America. Although 2k/1b prevalence is highest in the Caucasus mountain region (i.e., Armenia, Azerbaijan, and Georgia), the origin and migration patterns of CRF 2k/1b have remained obscure due to a paucity of available sequences. We assembled an alignment which spans the entire coding region of the HCV genome containing all available 2k/1b sequences (>500 nucleotides; n = 109) sampled in ninteen countries from public databases (102 individuals), additional newly sequenced genomic regions (from 48 of these 102 individuals), unpublished isolates with newly sequenced regions (5 additional individuals), and novel complete genomes (2 additional individuals) generated in this study. Analysis of this expanded dataset reconfirmed the monophyletic origin of 2k/1b with a recombination breakpoint at position 3,187 (95% confidence interval: 3,172–3,202; HCV GT1a reference strain H77). Phylogeography is a valuable tool used to reveal viral migration dynamics. Inference of the timed history of spread in a Bayesian framework identified Russia as the ancestral source of the CRF 2k/1b clade. Further, we found evidence for migration routes leading out of Russia to other former Soviet Republics or countries under the Soviet sphere of influence. These findings suggest an interplay between geopolitics and the historical spread of CRF 2k/1b.

Epidemiological trends among the population with chronic HCV infection in the Netherlands

BACKGROUND

As the field of antiviral therapy for chronic HCV infection is rapidly evolving, this study aimed to assess the epidemiological changes in patient and disease characteristics among individuals with chronic HCV infection.

METHODS

This study included all consecutive patients with chronic HCV monoinfection who were referred between 1990 and 2013 to the Erasmus MC University Medical Center Rotterdam, a large tertiary centre in the Netherlands. To identify trends over time, the study population was divided into six equal eras based on date of first visit to the outpatient clinic.

RESULTS

A total of 1,779 patients were diagnosed with chronic HCV infection. Mean age increased over time from 43.6 (sd 13.8) years to 51.7 (sd 11.2) years (P<0.001). The number of patients who were referred with cirrhosis increased over time, from 31 (25%) patients in Era 1 to 118 (42%) patients in Era 6 (P<0.001), respectively. More patients were referred with HCV genotype 1a and 3 in the last era, with 27 (48.2%) and 15 (14.0%) patients in Era 1 and 58 (54.2%) and 60 (21.8%) patients in Era 6 (P<0.001 both), respectively. The vast majority of patients (69.5%) were born between 1950 to 1975, with 62.5% of the patients being born between 1945 and 1965.

CONCLUSIONS

The HCV-infected population is ageing and is more often referred with severe liver disease. This study stresses the importance of urgently implementing national HCV screening programmes in order to be able to decrease the future burden of chronic HCV infection in the Netherlands.

The role the type of vascular access plays in the transmission of hepatitis C virus in a high prevalence hemodialysis unit

BACKGROUND

The necessity of having a vascular access site as well as extracorporeal blood circulation, may add to the risk for patients being dialyzed in units with high HCV prevalence of acquiring hepatitis C virus (HCV) infection. This study endeavors to determine the role the type of vascular access plays in the transmission of HCV infection in the hemodialysis (HD) unit of a Middle Eastern country.

METHODS

The records of 198 patients with end-stage renal disease (ESRD) enrolled on maintenance HD from November 1995 to November 2000 at this tertiary care center, were retrospectively reviewed to match the HCV prevalence and seroconversion rates among patients groups being dialyzed through various types of vascular accesses. Factors such as, number of units of blood transfused and dialytic age (time-span since the initiation of the HD treatment), implicated in transmission of HCV infection in HD units, were also recorded, and compared among these cohorts.

RESULTS

The overall, high HCV seroprevalence of 43.4% (86/198) and annual seroconversion rate of 8.6% per year were recorded. Patients with arteriovenous fistula (AVF) documented peak anti-HCV prevalence [61.7% (63/102)] and annual seroconversion rates (12.3%) as compared to lowest prevalence of 12.9% (4/34) and seroconversion rate of 2.5%, observed among patients with permanent Catheters (PC). Patients dialyzed through polytetrafluoroethylene (PTFE) grafts recorded the next highest HCV prevalence of 47.8% (11/23) with seroconversion rate of 9.5% but temporary catheter (TC) group had HCV prevalence of 19% (8/42) and seroconversion rate of 3.8% [Odd Ratio (OR)-1.58, 95% Confidence Interval (CI) (0.37-7.12), p-NS].

CONCLUSIONS

Considerably higher annual seroconversion rates in AVF [OR-10.90, 95% CI (3.2-40.0), p<0.0001] and PTFE [OR-5.71, 95% CI (1.31-26.79), p<0.016)] groups, appear to suggest that the patients being dialyzed through AVF and PTFE, carried significantly higher risk of acquisition of HCV infection compared to those dialyzed through TC and PC (reference group). This could possibly be attributed to likely accessibility of HCV to blood circulation due to possible breakdown of standard infection control precautions during repeated punctures and cannulations of AVF and PTFE to perform a HD, in a unit with high baseline HCV prevalence.

High prevalence of hepatitis C virus-ribonucleic acid positivity in anti-hepatitis C virus negative renal transplant patients

BACKGROUND

Hepatitis C virus (HCV) infection is common in renal transplant (RT) patients. Some of these patients remain anti-HCV negative despite presence of infection and these are identified by a positive HCV-ribonucleic acid (RNA) test.

METHODS

We studied 404 RT patients for prevalence of HCV-RNA positivity in anti-HCV negative patients. Serum was tested for presence of anti-HCV antibodies using a third generation HCV micro-ELISA (enzyme-linked immunosorbent assay) test, which utilises a combination of HCV structural and nonstructural antigens. The RNA was extracted from patient serum for HCV viral quantification using Quiagen Ql Amp Viral RNA mini extraction kit. The HCV-RNA viral load was performed on Corbet Rotor Gene 3000 thermocycler using Taqman principle.

RESULTS

About 308 patients were anti-HCV negative and 96 were anti-HCV positive, resulting in prevalence of overt HCV infection of 23.7%. A total of 130 anti-HCV negative patients tested positive for HCV-RNA making a prevalence of occult HCV infection of 42.2%. There was no significant difference in the rate of overt or occult HCV infection between males and females. Patients with HCV infection (whether overt or occult) had received more number of dialysis sessions (62.5 vs 32.2) and blood transfusions (2.78 vs 1.99) when compared to those without HCV infection (P=0.001). The mean duration on dialysis was also longer (8.15 months vs 4.53 months) in patients with HCV infection (P= 0.0001).

CONCLUSION

A direct test for HCV viraemia is important to accurately determine the epidemiology of HCV infection in RT patients who remain anti-HCV negative despite harbouring active HCV infection.

Risk factors of hepatitis C infection among Egyptian blood donors

BACKGROUND

Surveillance of infectious disease markers in the blood donor population is important in recognizing trends in prevalence and incidence of transfusion related infections in asymptomatic volunteer blood donors.

SUBJECTS AND METHODS

It was a cross sectional study. Samples were collected from volunteer blood donors and questionnaire was designed to collect the risk factors data. The prevalence of hepatitis C antibodies among 1,000 apparently healthy blood donors were determined.

OBJECTIVE

To estimate the prevalence of virus C hepatic infection and to illustrate the various socio-economic, behavioural and medical factors related to infection with Hepatitis C (HCV) among apparently healthy individuals. It contributed to analysis of the particularities of Egyptian blood donors and helped to better understand the challenges and solutions of blood safety.

RESULTS

The prevalence of HCV was 16.8%. There was an association of positive anti-HCV test with socio-demographic, medical and behavioural risk factors.

CONCLUSION

This study provided comprehensive and reliable information on the possible risk factors affecting spread of Hepatitis C in the area.

Origin and evolution of the unique hepatitis C virus circulating recombinant form 2k/1b

Since its initial identification in St. Petersburg, Russia, the recombinant hepatitis C virus (HCV) 2k/1b has been isolated from several countries throughout Eurasia. The 2k/1b strain is the only recombinant HCV to have spread widely, raising questions about the epidemiological background in which it first appeared. In order to further understand the circumstances by which HCV recombinants might be formed and spread, we estimated the date of the recombination event that generated the 2k/1b strain using a Bayesian phylogenetic approach. Our study incorporates newly isolated 2k/1b strains from Amsterdam, The Netherlands, and has employed a hierarchical Bayesian framework to combine information from different genomic regions. We estimate that 2k/1b originated sometime between 1923 and 1956, substantially before the first detection of the strain in 1999. The timescale and the geographic spread of 2k/1b suggest that it originated in the former Soviet Union at about the time that the world's first centralized national blood transfusion and storage service was being established. We also reconstructed the epidemic history of 2k/1b using coalescent theory-based methods, matching patterns previously reported for other epidemic HCV subtypes. This study demonstrates the practicality of jointly estimating dates of recombination from flanking regions of the breakpoint and further illustrates that rare genetic-exchange events can be particularly informative about the underlying epidemiological processes.

293 cells over-expressing human ADI1 and CD81 are permissive for serum-derived hepatitis C virus infection

Human aci-reductone dioxygenase 1 (ADI1) is a member of the Cupin superfamily. It binds to and inhibits the activities of membrane-type 1 matrix metalloproteinase, a protein known to interact with the tight junction protein, claudin-1. Previously, a variant protein, named submergence-induced protein-like factor (Sip-L), consisting of ADI1 amino acids 64-179, was found to support hepatitis C virus (HCV) infection and replication in 293 cells. In the present study, it was discovered that over-expression of human ADI1 in 293 cells (293-ADI1 cells) also supported HCV infection and replication. Using serum-derived HCV as an infectious source, enhanced cell uptake of HCV to a Northern blot detectable level was found in 293 cells over-expressing both CD81 and ADI1 (293-ADI1-CD81 cells). The enhanced cell entry was confirmed by the use of the vesicular stomatitis virus-based HCV pseudotype particles. However, transfection of HCV replicon RNA by electroporation into naïve 293 and 293-ADI1 cells revealed no difference in replication efficiency. Using the infectious J6/JFH chimera as an infectious source, the infectivity was compared between 293-ADI1-CD81 and Huh-7.5 cells. More infection foci were formed in the 293-ADI1-CD81 cells in the first round of infection. In conclusion, human ADI1 over-expression in 293 cells enhances cell entry but not replication of HCV. 293-ADI1-CD81 cells are permissive for serum-derived HCV infection.

Hepatitis C virus infection in mouse hepatoma cells co-expressing human CD81 and Sip-L

Although human CD81 has been shown to be essential for hepatitis C virus (HCV) infection, non-hepatic cells or transgenic animals expressing human CD81 alone did not support HCV replication. Co-expression of other cofactors was thus necessary for HCV replication. Previously, a hepatic factor named Sip-L was found to support HCV replication in an otherwise non-permissive cell line. To understand the species specificity of hepatic factors required for HCV replication, mouse hepatoma cells co-expressing human CD81 and Sip-L (Hepa1-6-CD81-Sip-L cells) were subjected for HCV infection assay. It was discovered that Hepa1-6-CD81-Sip-L cells were permissive for HCV infection and replication. An animal model was thus established by subcutaneous injection of the permissive cells into nude mice to generate tumors. Viral passages could be achieved in these animals. The antiviral effects of interferon and sodium stibogluconate administrated as a single agent or in combination were demonstrated in this animal model.

Detection of hepatitis C virus core antigen for early diagnosis of hepatitis C virus infection in plasma donor in China

AIM: To evaluate the efficacy of a new hepatitis C virus (HCV) core antigen assay developed in China.

METHODS: After the determination of HCV infection, 49 serial samples were selected from 11 regular plasma donors in 5 different plasma stations. To compare the performance of HCV core antigen detection and HCV PCR, these samples were genotyped, and each specimen was analyzed by ELISA for the detection of HCV core antigen and by qualitative HCV PCR.

RESULTS: Among all of the sequential samples, the original 13 specimens were HCV RNA-negative, and 36 samples were HCV RNA-positive. Twenty-seven samples (75%) were HCV core antigen-positive from these HCV RNA-positive specimens. Conversely, 27 samples (93.1%) were found HCV RNA-positive in HCV core antigen-positive samples. Intervals between HCV RNA and HCV core antigen-positive, as well as between HCV core antigen-positive and HCV antibody-positive were 36.0 and 32.8 d, respectively.

CONCLUSION: This HCV core antigen assay, developed in China, is able to detect much of anti-HCV-negative, HCV RNA-positive preseroconversion window period (PWP) plasma donations.

Pathogen inactivation techniques

The desire to rid the blood supply of pathogens of all types has led to the development of many technologies aimed at the same goal--eradication of the pathogen(s) without harming the blood cells or generating toxic chemical agents. This is a very ambitious goal, and one that has yet to be achieved. One approach is to shun the 'one size fits all' concept and to target pathogen-reduction agents at the Individual component types. This permits the development of technologies that might be compatible with, for example, plasma products but that would be cytocidal and thus incompatible with platelet concentrates or red blood cell units. The technologies to be discussed include solvent detergent and methylene blue treatments--designed to inactivate plasma components and derivatives; psoralens (S-59--amotosalen) designed to pathogen-reduce units of platelets; and two products aimed at red blood cells, S-303 (a Frale--frangible anchor-linker effector compound) and Inactine (a binary ethyleneimine). A final pathogen-reduction material that might actually allow one material to inactivate all three blood components--riboflavin (vitamin B2)--is also under development. The sites of action of the amotosalen (S-59), the S-303 Frale, Inactine, and riboflavin are all localized in the nucleic acid part of the pathogen. Solvent detergent materials act by dissolving the plasma envelope, thus compromising the integrity of the pathogen membrane and rendering it non-infectious. By disrupting the pathogen's ability to replicate or survive, its infectivity is removed. The degree to which bacteria and viruses are affected by a particular pathogen-reducing technology relates to its Gram-positive or Gram-negative status, to the sporulation characteristics for bacteria, and the presence of lipid or protein envelopes for viruses. Concerns related to photoproducts and other breakdown products of these technologies remain, and the toxicology of pathogen-reduction treatments is a major ongoing area of investigation. Clearly, regulatory agencies have a major role to play in the evaluation of these new technologies. This chapter will cover the several types of pathogen-reduction systems, mechanisms of action, the inactivation efficacy for specific types of pathogens, toxicology of the various systems and the published research and clinical trial data supporting their potential usefulness. Due to the nature of the field, pathogen reduction is a work in progress and this review should be considered as a snapshot in time rather than a clear picture of what the future will bring.

Identification of a specific marker for hepatitis C virus infection using capillary zone electrophoresis

BACKGROUND

Hepatitis C virus (HCV) infection is now becoming a common health problem in both developed and developing countries. The limitation of the available diagnostic approaches enhances the efforts to have a rapid, sensitive, and specific diagnostic testing for HCV infection. Capillary zone electrophoresis (CZE) is a fully automated analytical technique whose popularity is quickly increasing in the clinical chemistry laboratory. CZE can analyze nanoliters or less of samples with detection sensitivity at the attomole level (10(-18) mol) or less.

METHODS

CZE was optimized for the identification of a specific marker of HCV infection. The performance characteristics of the CZE for the detection of HCV RNA peak were evaluated in comparison with standard nested PCR.

RESULTS

A characteristic peak at 2.72 min was identified only in the CZE electropherogram of urine samples from HCV-infected individuals. The nature of the characteristic peak was investigated and confirmed to be HCV RNA using PCR and other biochemical treatments including RNase, DNase, and trypsin enzymes. CZE showed high degrees of sensitivity (94%) and specificity (96%) in comparison with the nested PCR.

CONCLUSION

CZE provides a rapid, inexpensive, sensitive, and specific analytical method for diagnosis and mass screening of a large number of HCV-infected individuals.

The impact of nurse understaffing on the transmission of hepatitis C virus in a hospital-based hemodialysis unit

OBJECTIVE

To determine the impact of nurse understaffing on the transmission of hepatitis C virus (HCV) infection in a large hospital-based hemodialysis (HD) unit with a high HCV prevalence.

SUBJECTS AND METHODS

The records of 198 patients (107 males and 91 females) with end-stage renal disease enrolled on long-term HD at King Fahad Hospital and Tertiary Care Center, Hofuf, Saudi Arabia, from August 1995 to August 2000, were retrospectively reviewed. The patients were assigned to HD groups of varying patient-to-nurse (P/N) ratios: group I, 2:1; group II, 3:1, and group III, 4:1. HCV prevalence, seroconversion rates, history of blood transfusion and dialysis age (time span since the initiation of the HD treatment) were recorded and compared.

RESULTS

The overall HCV prevalence and seroconversion rate per year were 43.4 and 8.6%, respectively. Group I had the lowest HCV prevalence and annual seroconversion rate (26.8%; 5.3%), followed by group II (43.6%; 8.7%); group III had the highest HCV prevalence and seroconversion rate (71.8%; 14.4%). Anti-HCV positivity was associated with a higher dialysis age.

CONCLUSION

The finding that the patients in the groups with the relatively higher P/N ratio had the significantly higher HCV prevalence and seroconversion rates per year indicates that understaffing is likely to play a major role in the transmission of HCV in HD units, and we suggest that improved staffing may be helpful in reducing the HCV transmission in such dialysis units.

Blood transfusion risks in the intensive care unit

This article reviews transfusion risks with particular emphasis on the critically ill. It describes the various types of noninfectious,infectious, and mild-to-severe reactions that can occur in a trans-fused patient. The article describes differential diagnosis of these reactions and the handling and treatment of the patient. Diagnosis of the type of transfusion reaction by laboratory tests is detailed. Finally, the article discusses the dangers of human error with possible strategies to combat this problem using new technologies.

Infecção pelo vírus da hepatite C na região Amazônica brasileira

O artigo avalia informações científicas disponíveis sobre a prevalência e características clínicas da infecção pelo virus da hepatite C na Amazônia Brasileira, uma área sabidamente endêmica para infecção pelos vírus das hepatites A, B e D. Toda a informação foi obtida através de extensa revisão bibliográfica de artigos originais e de revisão e de resumos publicados em periódicos conceituados ou em eventos científicos. Na Região Amazônica, a taxa de prevalência de infecção por VHC na população geral varia de 1,1 a 2,4%. Entre doadores de sangue as taxas de prevalência variam de 0,8% a 5,9%. O Estado do Pará (Amazônia oriental) e do Acre (Amazônia ocidental) apresentam as maiores taxas, 2% e 5,9%, respectivamente. Com relação à prevalência da infecção pelo VHC em grupos de risco, observa-se alta prevalência entre hemodiálisados (48,1% - 51,9%), profissionais de saúde (3,2%), contactantes de portadores do VHC (10%) e pacientes com lichen plannus (7,5%). Existe uma predominância significativa do genótipo 1, com maior freqüência do subtipo 1b. A infecção pelo VHC é similar em homens e mulheres e a maioria dos infectados têm mais de 39 anos de idade. A principal via de infecção é a parenteral e os principais fatores de risco são transfusão sangüínea e procedimentos cirúrgicos. O VHC raramente é responsável por hepatite aguda grave nesta região. Por outro lado, de todas as hepatites crônicas, 22,6% são atribuídas ao VHC na Amazônia Ocidental e 25% na Amazônia Oriental. Na Amazônia Brasileira, a infecção pelo VHC parece ter o mesmo comportamento da infecção em outras partes do mundo.

Epidemiological and clinical burden of chronic hepatitis B virus/hepatitis C virus infection. A multicenter Italian study

BACKGROUND/AIMS

This study assess prevalence, risk factors, and clinical and virological features of dual hepatitis B virus (HBV)/hepatitis C virus (HCV) infection.

METHODS

We evaluated 837 hepatitis B surface antigen positive patients, prospectively enrolled in 14 Italian units.

RESULTS

Anti-HCV was present in 59 cases (7%); age specific prevalences were 4.5% (0-30 years), 4.4% (>30-50) and 14% (>50). Independent predictors of dual infection were age >42 years, history of I.V. drug use (IDU), blood transfusion and residence in the South of the country. The strength of the association with IDU was high, but this exposure accounted for five coinfection cases only. Cirrhosis was present in 107 of the 709 patients with HBV alone (15.1%), in 30 of 69 with hepatitis D virus coinfection (43%) and in 17 of 59 with HCV coinfection (28.8%); a light alcohol use was marginally associated with cirrhosis. Of 36 B/C coinfected patients, 16 (44.4%) had only HBV-DNA in serum, (median age=47.5 years) five (13.9%) had both HBV-DNA and HCV-RNA (age=53), nine (25%) had HCV-RNA alone (age=59) and six (16.7%) tested negative for both.

CONCLUSIONS

This study depicts the epidemiological and clinical burden of dual HBV/HCV infection in Italy.

Inhibition of authentic hepatitis C virus replication by sodium stibogluconate

Using a hepatitis C virus (HCV) subgenomic RNA replicon system, drugs currently being used to treat other human diseases were examined for their antiviral activities against HCV. Several drugs including sodium stibogluconate, a compound used to treat leishmaniasis, were capable of suppressing replication of HCV replicon. The antiviral effect of sodium stibogluconate was subsequently verified using a cell line (293EBNA-Sip-L) previously proved to be permissive for HCV infection/replication. An ex vivo assay using fresh human liver slices established and a panel of human liver slices was obtained from biopsy samples of patients infected with HCV was used to examine the antiviral activity of this drug. A nearly complete suppression effect was achieved in four of six human liver slices at the drug concentration of 100 microg/ml, lower than what was required to treat leishmaniasis. A human trial is mandatory to understand its clinical value in treating chronic hepatitis C.

Ambiguity leads to uncertainty: ambiguous demands to blood donors

Blood donors must respond to standard control questions and comply to certain demands before donating blood, to exclude possible recent contamination. This study investigates whether donors had adequate knowledge about 'the immunological window period', and whether the standard questionnaire in use was understandable and clear. It was found that nearly 40% of the donors had inadequate knowledge about 'the immunological window period' and that 10-40% of the donors would respond in various ways to different interpretations of the formulations of the questionnaire, indicating that the questionnaire was ambiguous. It was concluded that these factors could increase the risk of donating on wrong conditions. Demands and control questions posed to donors must be void of ambiguous formulations and take proper account of actual human sexual behaviours and life styles. Finally, it is suggested that blood banks must offer practical solutions (such as a 'fake donation') for temporarily rejected donors in order to respect their private integrity.

A novel antigen detection immunoassay for field diagnosis of hepatitis C virus infection

The limitations of dominant methods-based on the detection of anti-HCV antibodies or HCV viremia currently used for the diagnosis of HCV infection enhance efforts to have a rapid, simple, sensitive, and specific alternative diagnostic approach to detect viral antigens. A highly reactive IgG antibody was raised to HCV-NS4 recombinant antigen. The produced antibody showed no cross-reactivity with the other HCV structural and nonstructural recombinant antigens (C1 + 2, C3 + 4, E2/NS1, NS3, NS5). The well established ELISA technique was adapted to detect the new target HCV-NS4 antigen in serum samples. Extremely high agreement was found between the results of ELISA and qualitative detection of HCV-RNA, using a RT-PCR test as a gold standard for the diagnosis of HCV infection. Based on these encouraging results, a novel enzyme immunoassay; dot-ELISA was developed for rapid (approximately 5 min) and simple qualitative detection of the target HCV antigen in serum. The developed method detected the HCV target antigen in 95% of serum samples from HCV infected individuals, with a specificity of 97% using sera of noninfected individuals in comparison with PCR test. The antigen detection method showed high predictive values of positive (99%) and negative (90%). Moreover, the dot-ELISA could detect the HCV target antigen in sera negative for anti-HCV Abs, but positive for HCV-RNA, and in sera of HCV infected individuals with low viremia, as well as those with high viremia, using quantitative RT-PCR. Accordingly, the developed highly sensitive and specific HCV antigen detection method could be applied for mass screening of HCV infection.

Declared hepatitis C screening strategies in blood recipients in French hospitals

AIMS OF THE STUDY

In spite of official recommendations and measures in France, screening strategies of hepatitis C performed in the field of transfusion are not clearly known. The aim of this study is to describe the screening strategies before and after the current year of the transfusion in blood recipients in several French medical departments and hospitals.

MATERIALS AND METHODS

A qualitative study using the key informant technique was carried out. A sample of 179 departments and 64 hospitals in charge of patients transfused with low or high-volumes of homologous blood products was constituted. The key informants were asked about the number of homologous blood products, the number of recipients transfused in the hospital, the volume of transfusion performed, the existence of a single defined screening strategy, the time of prescription of the biological tests (before or after transfusion), the tests performed on cryopreserved blood samples, and the indications of the transfusion.

RESULTS

The main screening strategy was HCV serology (second or third generation of enzyme immunoassays) with transaminase assessments before and after transfusion in 14% of the declared screening strategies. Screening tests were more frequently prescribed after transfusion, in at least 64% of the declared screening strategies according to the volume of transfusion. HCV serology was the common test prescribed in 61 and 50% of the screening strategies for low and high-volume transfusion respectively. The screening strategies showed a large heterogeneity combining HCV serology, transaminase assessment, before or after transfusion.

CONCLUSION

A great heterogeneity of screening strategies was found. The most frequent was HCV serology with transaminase assessment before and after transfusion. Recommendations on screening strategies are needed in order to limit practice heterogeneity. This study will help building a cost-efficacy model in order to guide public health decision making.

Detection and prevention of hepatitis C in dialysis patients and renal transplant recipients. A long-term follow up (1989-January 1997)

BACKGROUND

Hepatitis C is frequent problem in dialysis wards.

DESIGN

A long time (1989-97) follow up of hepatitis C virus (HCV) infection in a Swedish nephrology unit was performed with anti-HCV screening, confirmatory antibody tests, viral RNA detection and molecular characterization. Case histories were reviewed with focus, onset of infection, liver morbidity and mortality.

RESULTS

In October 1991, 10% (19 of 184) of the patients in the unit (haemodialysis-, peritoneal dialysis and transplanted patients) were verified or suspected HCV carriers, whilst the number at the end of 1996 was 8%, (13 of 157). Most patients were infected before 1991 but only in one case from a known HCV-infected blood donor. No new HCV infections associated with haemodialysis occurred during the study period. A total of 13 of 24 viremic patients had HCV genotype 2b, a pattern suggesting nosocomial transmission. This was further supported by phylogenetic analysis of HCV viral isolates in seven. HCV viremia was also common in patients with an incomplete anti-HCV antibody pattern as 8 of the 12 indeterminant sera were HCV-RNA positive.

CONCLUSIONS

Awareness, prevention, identification of infected patients and donor testing limited transmission. Indeterminant recombinant immunoblot assays (RIBA)-results should be regarded with caution as a result of the relative immunodeficiency in uremic patients. Our data indicate nosocomial transmission in several patients.

Novel approach to reduce the hepatitis C virus (HCV) window period: clinical evaluation of a new enzyme-linked immunosorbent assay for HCV core antigen

The window period in hepatitis C virus (HCV) infection is still a major problem in ensuring blood safety. HCV RNA detection by nucleic acid amplification technology-based tests has contributed to reduce the infectivity of blood products, but it is expensive, time-consuming and affected by a high prevalence of false-positive results. The aim of this study was to assess the performance of a newly developed enzyme immunoassay for the detection of HCV core antigen and its suitability for use in the screening of blood units in order to identify infecting samples that do not contain specific antibodies. For evaluation of laboratory performance, different samples were selected: to evaluate specificity, we tested 2,586 sera from blood donors, 500 general population samples, and 58 "difficult sera". All samples were tested by two screening assays, and results were negative. To estimate clinical sensitivity, 103 HCV RNA-positive, anti-HCV-negative samples, 6 natural seroconversion panels, and 9 commercial seroconversion panels were tested. Intra- and interassay precision were determined on two HCV-RNA-positive, anti-HCV-negative sera. Seventeen (0.66%) blood donor samples, 2 (0.4%) general population samples, and 2 (3.44%) difficult sera were initially reactive; 3 sera were positive on repetition. These 21 samples tested by reverse transcription-PCR were negative. The clinical sensitivity calculated with seroconversion panels and seroconverted patient samples was very similar to PCR sensitivity: 95% of PCR-positive, antibody-negative samples contained detectable HCV antigen. Data on intra- and interassay precision showed dispersion indices with values of less than 10%. In conclusion, the HCV antigen assay showed high sensitivity and specificity and could become a useful means of improving the safety of blood and blood products.

Pathogenesis, diagnosis and management of hepatitis C

The hepatitis C virus (HCV) is the leading cause of chronic liver disease worldwide. It is estimated that about 170 million people are chronically infected with HCV. Chronic hepatitis C is a major cause of cirrhosis and hepatocellular carcinoma and HCV-related end-stage liver disease is, in many countries, the first cause of liver transplantation. HCV infection is characterized by its propensity to chronicity. Because of its high genetic variability, HCV has the capability to escape the immune response of the host. HCV is not directly cytopathic and liver lesions are mainly related to immune-mediated mechanisms, which are characterized by a predominant type 1 helper cell response. Co-factors influencing the outcome of the disease including age, gender and alcohol consumption are poorly understood and other factors such as immunologic and genetic factors may play an important role. Recent studies have shown that the combination therapy with alpha interferon and ribavirin induces a sustained virological response in about 40% of patients with chronic hepatitis C. The sustained response rates are mainly dependent on the viral genotype (roughly 60% in genotype non-1 and 30% in genotype 1). Reliable diagnostic tools are now available and useful for detecting HCV infection, to quantify viral load and to determine the viral type. The assessment of the viral quasispecies and the characterization of viral sequences might be clinically relevant but standardized and simple techniques are needed. The lack of animal models and of in vitro culture systems hampers the understanding of the pathogenesis of chronic hepatitis C and the development of new antivirals. New therapeutic schedules with higher and/or daily doses of alpha interferon do not seem to improve the efficacy greatly. The conjugation with polyethylene glycol (PEG) improved the pharmacodynamics and the efficacy of alpha interferon. Emerging new therapies include inhibitors of viral enzymes (protease, helicase and polymerase), cytokines (IL-12 and IL-10), antisense oligonucleotides and ribozymes. The first candidate compounds should be available in the next few years. The development of an effective vaccine remains the most difficult and pressing challenge. Because of the high protein variability of HCV, protective vaccines could be extremely difficult to produce and therapeutic vaccines seem more realistic. Considerable progress has been made in the field of HCV since its discovery 10 years ago but a major effort needs to be made in the next decade to control HCV-related liver disease.