Occult hepatitis C virus infection: what does it mean?

Detection of hepatitis C virus (HCV) RNA in the peripheral blood mononuclear cells of HCV-infected patients following sustained virologic response

It is unclear whether direct-acting antiviral drugs (DAAs) result in the complete eradication of HCV infection or whether some quantities of the virus may persist after achieving a sustained virologic response (SVR). Aim The aim of this work was to study the possibility of the persistence of HCV RNA in peripheral blood mononuclear cells (PBMCs) after achieving SVR following DAA treatment. This study included 100 patients infected with HCV genotype 4, who were candidates for receiving DAAs and who achieved SVR during follow-up, as determined at 12 and/or 24 weeks following the end of treatment. All patients were subjected to demographic, biochemical and hematological assessments. Detection of HCV RNA in the serum and PBMCs and determination of the HCV genotype were performed with real-time PCR. We detected HCV RNA in the PBMCs of 20 out of 100 (20%) patients infected with HCV genotype 4, who achieved SVR. However, the persistent viral load in the PBMCs was very low (range: 400-900 U/mL; mean ± SD: 645.45 ± 153 U/mL). Multiple logistic regression analysis showed that only the higher posttreatment levels of aspartate transaminase (AST) were significantly predictive of HCV RNA persistence in the PBMCs (OR: 1.29; 95% CI: 1.08-1.55). Additionally, according to the Cox proportional hazard model, liver cirrhosis was the only significant risk factor for the persistence of HCV infection in PBMCs (HR: 5.8; 95% CI: 1.3-26.1; P < 0.02). Our results indicated the persistence of HCV RNA in some HCV patients who achieved SVR after treatment with DAAs.

Fatal Hepatitis C after Chemotherapy in a Patient with Malignant Lymphoma: Possible Reactivation of Seronegative Occult Hepatitis C Virus Infection Due to Chemotherapy

A 79-year-old man with lymphoma who tested negative for anti-hepatitis C virus (HCV) antibody received rituximab-containing chemotherapy. Liver dysfunction of unknown cause had persisted since the second cycle of chemotherapy. Ten months after treatment, he rapidly developed massive ascites and atrophy of the liver, and we detected HCV RNA in his serum using real time polymerase chain reaction. Furthermore, medical interviews showed that the patient had no episodes for acute HCV infection, but he did have a history of unspecified liver dysfunction. These findings support the possibility of the reactivation of seronegative occult HCV infection due to chemotherapy in a cancer patient.

Long-term follow-up after cure from chronic hepatitis C virus infection shows occult hepatitis and a risk of hepatocellular carcinoma in noncirrhotic patients

OBJECTIVES

Curing of hepatitis C virus (HCV) infection primarily aims to prevent severe liver complications. Our objectives were to investigate the long-term presence and impact of occult HCV infection (OCI) and to study the outcomes in terms of liver disease after virological cure.

PATIENTS AND METHODS

A total of 97 patients with achieved sustained virological response (SVR) during 1990-2005 were followed either by a clinical follow-up (FU) visit with blood sampling and liver elastography (n=54) or through national registries for outcomes (n=43). To diagnose OCI among patients with SVR, a highly sensitive method was used to detect HCV-RNA traces in whole blood. The FU duration was a median of 10.5 years, with samples up to 21.5 years after the end of treatment (EOT).

RESULTS

The majority of patients [52 (96%)] were HCV-RNA negative at FU, and regression of fibrosis was statistically significant. OCI was found in two (4%) of them at 8 and 9 years after EOT. These patients had F1 and F2 fibrosis before treatment and F2 at FU, but no other abnormal findings. Three previously noncirrhotic men were diagnosed with hepatocellular carcinoma 8-11 years after EOT.

CONCLUSION

Occult infection could be detected many years after the achievement of SVR but was not associated with serious liver disease. The majority had persistent viral eradication and regression of fibrosis after SVR. However, an increased risk of hepatocellular carcinoma may persist in the long term after SVR even in noncirrhotic patients. Further studies with FU after direct-acting antiviral therapy and on the long-term impact after cure are needed.

Prevalence and risk factors of Occult Hepatitis C infections in blood donors from Mexico City

Background

The circulatory system is the main mechanism for transmission of the Hepatitis C Virus (HCV). A new class of HCV infections, Occult HCV infection (OCI), is defined as the presence of HCV-RNA in hepatocytes with the absence of HCV in the serum/plasma utilizing current laboratory assays. Different groups have reported the prevalence of OCI; however, its associated risk factors have not been established. In Mexico, there are no reports about OCI, so the objective of our study was to determine the prevalence of OCI in total blood donors in Mexico City, as well as its associated risk factors.

Methods

Blood donors that were considered eligible for donation, according to NOM 253-SSA1-2012, were randomly selected. Demographic data was collected from 1,037 donors. Plasma and peripheral blood mononuclear cells were assessed for HCV-RNA. The presence of HCV-RNA was determined by nested PCR for the 5'-UTR region. Logistic regression was used to calculate the odds ratio (OR) and 95% confidence interval (95%CI) to determine the level of association.

Results

The prevalence of OCI was 3.4% among blood donors. Homosexual relationships (OR = 5.52, 95%CI: 1.53–19.92, p<0.05) and acupuncture (OR = 3.56, 95%CI: 1.41–8.98, p<0.05) were significantly associated with OCI.

Conclusion

There is a significant presence of OCI in the blood donor population in Mexico City. The main risk factors for OCI transmission are homosexual relationships and acupuncture. This study supports the increased use of sensitive and specific screening tests for blood bank testing.

Authentic Patient-Derived Hepatitis C Virus Infects and Productively Replicates in Primary CD4+ and CD8+ T Lymphocytes In Vitro

Accumulated evidence indicates that immune cells can support the replication of hepatitis C virus (HCV) in infected patients and in culture. However, there is a scarcity of data on the degree to which individual immune cell types support HCV propagation and on characteristics of virus assembly. We investigated the ability of authentic, patient-derived HCV to infect in vitro two closely related but functionally distinct immune cell types, CD4⁺ and CD8⁺ T lymphocytes, and assessed the properties of the virus produced by these cells. The HCV replication system in intermittently mitogen-stimulated T cells was adapted to infect primary human CD4⁺ or CD8⁺ T lymphocytes. HCV replicated in both cell types although at significantly higher levels in CD4⁺ than in CD8⁺ T cells. Thus, the HCV RNA replicative (negative) strand was detected in CD4⁺ and CD8⁺ cells at estimated mean levels ± standard errors of the means of 6.7 × 10² ± 3.8 × 10² and 1.2 × 10² ± 0.8 × 10² copies/μg RNA, respectively (P < 0.0001). Intracellular HCV NS5a and/or core proteins were identified in 0.9% of CD4⁺ and in 1.2% of CD8⁺ T cells. Double staining for NS5a and T cell type-specific markers confirmed that transcriptionally competent virus replicated in both cell types. Furthermore, an HCV-specific protease inhibitor, telaprevir, inhibited infection in both CD4⁺ and CD8⁺ cells. The emergence of unique HCV variants and the release of HCV RNA-reactive particles with biophysical properties different from those of virions in plasma inocula suggested that distinct viral particles were assembled, and therefore, they may contribute to the pool of circulating virus in infected patients.IMPORTANCE Although the liver is the main site of HCV replication, infection of the immune system is an intrinsic characteristic of this virus independent of whether infection is symptomatic or clinically silent. Many fundamental aspects of HCV lymphotropism remain uncertain, including the degree to which different immune cells support infection and contribute to virus diversity. We show that authentic, patient-derived HCV productively replicates in vitro in two closely related but functionally distinct types of T lymphocytes, CD4⁺ and CD8⁺ cells. The display of viral proteins and unique variants, the production of virions with biophysical properties distinct from those in plasma serving as inocula, and inhibition of replication by an antiviral agent led us to ascertain that both T cell subtypes supported virus propagation. Infection of CD4⁺ and CD8⁺ T cells, which are central to adaptive antiviral immune responses, can directly affect HCV clearance, favor virus persistence, and decisively influence the development and progression of hepatitis C.

Vertically acquired hepatitis C virus infection: Correlates of transmission and disease progression

The worldwide prevalence of hepatitis C virus (HCV) infection in children is 0.05%-0.4% in developed countries and 2%-5% in resource-limited settings, where inadequately tested blood products or un-sterile medical injections still remain important routes of infection. After the screening of blood donors, mother-to-child transmission (MTCT) of HCV has become the leading cause of pediatric infection, at a rate of 5%. Maternal HIV co-infection is a significant risk factor for MTCT and anti-HIV therapy during pregnancy seemingly can reduce the transmission rate of both viruses. Conversely, a high maternal viral load is an important, but not preventable risk factor, because at present no anti-HCV treatment can be administered to pregnant women to block viral replication. Caution is needed in adopting obstetric procedures, such as amniocentesis or internal fetal monitoring, that can favor fetal exposure to HCV contaminated maternal blood, though evidence is lacking on the real risk of single obstetric practices. Mode of delivery and type of feeding do not represent significant risk factors for MTCT. Therefore, there is no reason to offer elective caesarean section or discourage breast-feeding to HCV infected parturients. Information on the natural history of vertical HCV infection is limited. The primary infection is asymptomatic in infants. At least one quarter of infected children shows a spontaneous viral clearance (SVC) that usually occurs within 6 years of life. IL-28B polymorphims and genotype 3 infection have been associated with greater chances of SVC. In general, HCV progression is mild or moderate in children with chronic infection who grow regularly, though cases with marked liver fibrosis or hepatic failure have been described. Non-organ specific autoantibodies and cryoglobulins are frequently found in children with chronic infection, but autoimmune diseases or HCV associated extrahepatic manifestations are rare.

Occult Hepatitis C Virus Infection in Hemodialysis Patients; Single Center Study

INTRODUCTION

A new form of hepatitis C virus infection, known as occult hepatitis C virus (HCV) infection, is characterized by the presence of HCV_RNA in the liver or peripheral blood mononuclear cells (PBMCs). However, no serological markers of infection occur and there is not as much damage to the liver damage as is produced by chronic hepatitis C. There is a high incidence of HCV infection among hemodialysis patients, there is significant concern about viral transmission. HCV infection is a major problem in hemodialysis (HD) units even though blood products are screened for anti-HCV antibodies and other precautions are taken. The aim of this study was to determine the prevalence of occult HCV infection in PBMC in chronic hemodialysis (CHD) patients in the dialysis unit at Theodor Bilharz Research Institute (TBRI) with HCV antibodies and HCV RNA negativity irrespective of their liver function tests.

METHODS

Fifty-three patients who were repeatedly were anti-HCV negative and serum HCV-RNA negative and on regular hemodialysis for > six months were enrolled in the study, which was conducted in the dialysis unit of Nephrology Department at TBRI; there were 10 healthy matched controls. The patients were classified into two groups according to the result HCV RNA in their PBMCs. Serological markers of HCV infection, including anti-HCV antibody and serum HCV-RNA, were repeatedly negative for all patients included in the study. We collected serum and PBMC samples from the patients on the day they entered the study. The test of all serum samples for anti-HCV antibodies and HCV-RNA was repeated by RT-PCR to ensure that the patients did not have these HCV serologic markers, We also measured their ALT and GGT levels.

RESULTS

Occult hepatitis C virus infection (OCI) was detected in 15.1% of our CHD patients without any evidence of chronic liver disease.

CONCLUSION

Occult HCV infection was present among the hemodialysis patients irrespective of whether they had persistent abnormal values of liver enzymes for which no cause had been identified. Further study is required to determine the clinical significance of occult HCV infections in these patients.

Occult HCV Infection: The Current State of Knowledge

Context

Occult HCV infection (OCI) is defined as the presence of HCV-RNA in hepatocytes and the absence of HCV in the serum according to usual tests. We aimed to define OCI and provide information about the currently available diagnostic methods. Then we focus on specific groups that are at high risk of OCI and finally investigate immune responses to OCI and the available treatment approaches.

Evidence Acquisition

PubMed, Scopus and Google Scholar were comprehensively searched with combination of following keywords: “occult”, “hepatitis C virus” and “occult HCV infection”. The definition of OCI, diagnostic methods, specific groups that are at high risk and available treatment approaches were extract from literature. An analysis of available articles on OCI also was done based on Scopus search results.

Results

OCI has been reported in several high-risk groups, especially in hemodialysis patients and subjects with cryptogenic liver disease. Furthermore, some studies have proposed a specific immune response for OCI in comparison with chronic hepatitis C (CHC).

Conclusions

With a clinical history of approximately 11 years, occult HCV infection can be considered an occult type of CHC. Evidences suggest that considering OCI in these high-risk groups seems to be necessary. We suggest that alternative diagnostic tests should be applied and that there is a need for the participation of all countries to determine the epidemiology of this type of HCV infection. Additionally, evaluating OCI in blood transfusion centers and in patients who receive large amounts of blood and clotting factors, such as patients with hemophilia, should be performed in future projects.

Interactions between Hepatitis C Virus and the Human Apolipoprotein H Acute Phase Protein: A Tool for a Sensitive Detection of the Virus

The Hepatitis C virus (HCV) infection exhibits a high global prevalence frequently associated with hepatocellular carcinoma, taking years to develop. Despite the standardization of highly sensitive HCV quantitative RT-PCR (qRT-PCR) detection methods, false-negative diagnoses may be generated with current methods, mainly due to the presence of PCR inhibitors and/or low viral loads in the patient’s sample. These false-negative diagnoses impact both public health systems, in developing countries, and an in lesser extent, in developed countries, including both the risk of virus transmission during organ transplantation and/or blood transfusion and the quality of the antiviral treatment monitoring. To adopt an appropriate therapeutic strategy to improve the patient’s prognosis, it is urgent to increase the HCV detection sensitivity. Based upon previous studies on HBV, we worked on the capacity of the scavenger acute phase protein, Apolipoprotein H (ApoH) to interact with HCV. Using different approaches, including immunoassays, antibody-inhibition, oxidation, ultracentrifugation, electron microscopy and RT-PCR analyses, we demonstrated specific interactions between HCV particles and ApoH. Moreover, when using a two-step HCV detection process, including capture of HCV by ApoH-coated nanomagnetic beads and a home-made real-time HCV-RT-PCR, we confirmed the presence of HCV for all samples from a clinical collection of HCV-seropositive patients exhibiting an RT-PCR COBAS® TaqMan® HCV Test, v2.0 (COBAS)-positive result. In contrast, for HCV-seropositive patients with either low HCV-load as determined with COBAS or exhibiting HCV-negative COBAS results, the addition of the two-step ApoH-HCV-capture and HCV-detection process was able to increase the sensitivity of HCV detection or more interestingly, detect in a genotype sequence-independent manner, a high-proportion (44%) of HCV/RNA-positive among the COBAS HCV-negative patients. Thus, the immune interaction between ApoH and HCV could be used as a sample preparation tool to enrich and/or cleanse HCV patient’s samples to enhance the detection sensitivity of HCV and therefore significantly reduce the numbers of false-negative HCV diagnosis results.

Persistence of Hepatitis C Virus Traces after Spontaneous Resolution of Hepatitis C

Hepatitis C virus (HCV) frequently causes chronic hepatitis, while spontaneous recovery from infection is infrequent. Persistence of HCV after self-limited (spontaneous) resolution of hepatitis C was rarely investigated. The current study aimed to assess incidence and robustness of HCV persistence after self-resolved hepatitis C in individuals with normal liver enzymes and undetectable virus by conventional tests. Applying high sensitivity HCV RNA detection approaches, we analyzed plasma and peripheral blood mononuclear cells (PBMC) from individuals with previous hepatitis C infection. Parallel plasma and PBMC from 24 such non-viraemic individuals followed for 0.3–14.4 (mean 6.4) years were examined. Additional samples from 9 of them were obtained 4.5–7.2 (mean 5.9) years later. RNA was extracted from 250 μl plasma and, if HCV negative, from ~5 ml after ultracentrifugation, and from ex vivo stimulated PBMC. PBMC with evidence of HCV replication from 4 individuals were treated with HCV protease inhibitor, telaprevir. HCV RNA was detected in 14/24 (58.3%) plasma and 11/23 (47.8%) PBMC obtained during the first collection. HCV RNA replicative strand was evident in 7/11 (63.6%) PBMC. Overall, 17/24 (70.8%) individuals carried HCV RNA at mean follow-up of 5.9 years. Samples collected 4.5–7.2 years later revealed HCV in 4/9 (44.4%) plasma and 5/9 (55.5%) PBMC, while 4 (80%) of these 5 PBMC demonstrated virus replicative strand. Overall, 6/9 (66.7%) individuals remained viraemic for up to 20.7 (mean 12.7) years. Telaprevir entirely eliminated HCV replication in the PBMC examined. In conclusion, our results indicate that HCV can persist long after spontaneous resolution of hepatitis C at levels undetectable by current testing. An apparently effective host immune response curtailing hepatitis appears insufficient to completely eliminate the virus. The long-term morbidity of asymptomatic HCV carriage should be examined even in individuals who achieve undetectable HCV by standard testing and their need for treatment should be assessed.

A New Twist to a Chronic HCV Infection: Occult Hepatitis C

Background. The prevalence of occult hepatitis C infection (OCI) in the population of HCV-RNA negative but anti-HCV positive individuals is presently unknown. OCI may be responsible for clinically overt recurrent disease following an apparent sustained viral response (SVR) weeks to years later. Purpose. To review the available current literature regarding OCI, prevalence, pathogenic mechanisms, clinical characteristics, and future directions. Data Sources. Searching MEDLINE, article references, and national and international meeting abstracts for the diagnosis of OCI (1990-2014). Data Synthesis. The long-term followup of individuals with an OCI suggests that the infection can be transient with the loss of detectable HCV-RNA in PPBMCs after 12-18 months or alternatively exist intermittently and potentially long term. The ultimate outcome of HCV infection is decided by interplay between host immune responses, antiviral therapies, and the various well-identified viral evasion mechanisms as well as the presence of HCV infection within extrahepatic tissues. Conclusion. The currently widely held assumption of a HCV-cure in individuals having had "SVR" after 8-12 weeks of a course of DAA therapy as recently defined may not be entirely valid. Careful longitudinal followup utilizing highly sensitive assays and unique approaches to viral isolation are needed.

Differential expression of interferon alpha inducible genes in peripheral blood mononuclear cells from patients chronically infected with hepatitis C virus and healthy donors

The impact of exposure to interferon-alpha (IFN-α) on gene expression in peripheral blood mononuclear cells (PBMC) from hepatitis C virus (HCV)-infected and healthy individuals was investigated to recognize whether their PBMC differ in expression of IFN-inducible genes (ISGs) following treatment with IFN-α2b. PBMC obtained from healthy and treatment-naïve HCV-infected patients were cultured with IFN-α2b for 30min, 2h, 4h and 72h, and gene expression was analyzed using mRNA microarray technology. IFN-α caused differential up-regulation of many known ISGs in PBMC from both HCV-infected and healthy subjects. In comparison to untreated controls, the highest augmentation in PBMC ISG expression occurred after 4-hour exposure to IFN-α2b in both groups. The analysis identified 84 transcripts, representing 64 known and 2 unknown genes, that were up-regulated by at least 5-fold in PBMC from infected and uninfected individuals. However, the expression of IFN-α inducible genes was impaired in the PBMC from HCV-infected individuals compared to healthy controls. This was due to an increased baseline expression of the transcripts in PBMC of HCV-infected patients. These findings expand our understanding of IFN-responses in HCV-infected individuals and suggest that functions of PBMC, which include immune effector cells, are altered in patients chronically infected with HCV.

Hepatitis C virus-specific cellular immune responses in sustained virological responders with viral persistence in peripheral blood mononuclear cells

BACKGROUND & AIMS

Hepatitis C virus (HCV)-RNA detection in peripheral blood mononuclear cells (PBMCs) after recovery from HCV infection, is a type of occult HCV infection although is unclear how the viral persistence in PBMCs affects HCV-specific T-cell responses. The aim of this study was to investigate if cellular immune responses are modified by HCV persistence in PBMCs.

METHODS

HCV-specific CD4(+) and CD8(+) T-cell responses against six HCV peptides, situated within the non-structural (NS) proteins NS3, NS4b and NS5b, were measured by flow cytometry-through intracellular detection of gamma interferon (IFN-γ) or interleukin 4 (IL-4) and CD69 expression- in 27 sustained virological responders (SVR): 13 with and 14 without occult HCV infection in PBMCs, detected by strand-specific real-time PCR. Ten healthy individuals and 14 chronically infected patients with viraemia, were included as controls.

RESULTS

SVR without occult infection showed a higher percentage of activated CD4(+) cells against peptides belonging to NS3 (p124, p153) and NS5b (p257, p294), activated CD8(+) cells against NS3 (p124, p153, p158) and NS5b-p294, as well as an elevated percentage of CD4(+) cells releasing IFN-γ + IL-4 against NS3-p153, and by CD8(+) cells against NS3 (p124, p153). SVR without occult infection showed a higher percentage of activation and release of IFN-γ + IL-4 by both cell subpopulations than the two group of controls, in contrast to SVR with occult infection.

CONCLUSION

The lower HCV-specific T-cell response found in SVR with occult infection indicates that the immune response may be impaired when the virus persists in PBMCs.

Prevalence of occult hepatitis C infection in chronic hemodialysis and kidney transplant patients

BACKGROUND & AIMS

Detection of hepatitis C virus (HCV) RNA in peripheral blood mononuclear cells (PBMC) and/or hepatocytes in absence of HCV RNA in serum, designated as 'occult HCV infection', has been a matter of controversy in recent years. We investigated for the first time the prevalence of occult HCV infection in large cohorts of chronic hemodialysis (CHD) and kidney transplant (KTx) patients.

METHODS

We enrolled 417 CHD patients, 417 KTx recipients and 2 control groups - 25 anti-HCV (antibody against HCV)-positive and HCV RNA-positive patients with chronic hepatitis C, and 40 anti-HCV-, HCV RNA-, and HBsAg-negative healthy subjects. HCV RNA was tested in serum and PBMC using a sensitive commercial assay.

RESULTS

In CHD patients, the prevalence of anti-HCV was 3.6% (15/417) and of positive serum HCV RNA 2.4% (10/417). HCV RNA was detected in PBMC in 1/407 (0.25%) HCV serum RNA-negative patients ("occult HCV infection"). In KTx recipients, prevalence of anti-HCV was 4.8% (20/417) and of positive serum HCV RNA 4.6% (19/417). Occult HCV infection was found in 2/398 (0.5%) serum HCV RNA-negative patients. On a mean longitudinal follow-up of 30months of the 3 patients with occult HCV infection, there was no clinical or virological evidence of HCV infection.

CONCLUSIONS

The prevalence of occult HCV infection was very low in our CHD and KTx patients, and it did not appear to be clinically relevant. Further studies in geographic populations with high HCV endemicity are required to clarify the significance of occult HCV infection in these patient groups.

Direct effects of hepatitis C virus on the lymphoid cells

It has been reported that the direct binding of hepatitis C virus (HCV) and/or the replication of HCV in the extrahepatic organs and, especially, lymphoid cells, might affect the pathogenesis of extrahepatic diseases with HCV infection. More than one decade ago, several reports described the existence of HCV-RNA in peripheral blood mononuclear cells. Moreover, many reports describing the existence of HCV in B lymphocytes and B cell lymphoma have been published. In addition to B lymphocytes, it was reported that HCV replication could be detected in T lymphocytes and T cell lines. Among the extrahepatic diseases with HCV infection, mixed cryoglobulinemia-related diseases and autoimmune-related diseases are important for understanding the immunopathogensis of HCV persistent infection. Moreover, HCV persistent infection can cause malignant lymphoma. The biological significance of lymphotropic HCV has not yet become clear. However, several candidates have been considered for a long time. One is that lymphotropic HCV is an HCV reservoir that might contribute to the recurrence of HCV infection and difficult-to-treat disease status. The other important issue is the carcinogenesis of the lymphoid cells and disturbances of the immune responses. Therefore, the extrahepatic diseases might be induced by direct interaction between HCV and lymphoid cells. In this article, we summarize various studies showing the direct effect of HCV on lymphoid cells and discuss the biological significance of lymphotropic HCV.

Persistence of hepatitis C virus during and after otherwise clinically successful treatment of chronic hepatitis C with standard pegylated interferon α-2b and ribavirin therapy

Resolution of chronic hepatitis C is considered when serum HCV RNA becomes repeatedly undetectable and liver enzymes normalize. However, long-term persistence of HCV following therapy with pegylated interferon-α/ribavirin (PegIFN/R) was reported when more sensitive assays and testing of serial plasma, lymphoid cells (PBMC) and/or liver biopsies was applied. Our aim was to reassess plasma and PBMCs collected during and after standard PegIFN/R therapy from individuals who became HCV RNA nonreactive by clinical testing. Of particular interest was to determine if HCV genome and its replication remain detectable during ongoing treatment with PegIFN/R when evaluated by more sensitive detection approaches. Plasma acquired before (n = 11), during (n = 25) and up to 12–88 weeks post-treatment (n = 20) from 9 patients and PBMC (n = 23) from 3 of them were reanalyzed for HCV RNA with sensitivity <2 IU/mL. Clone sequencing of the HCV 5′-untranslated region from plasma and PBMCs was done in 2 patients. HCV RNA was detected in 17/25 (68%) plasma and 8/10 (80%) PBMC samples collected from 8 of 9 patients during therapy, although only 5.4% plasma samples were positive by clinical assays. Among post-treatment HCV RNA-negative plasma samples, 9 of 20 (45.3%) were HCV reactive for up to 59 weeks post-treatment. Molecularly evident replication was found in 6/12 (50%) among PBMC reactive for virus RNA positive strand collected during or after treatment. Pre-treatment point mutations persisted in plasma and/or PBMC throughout therapy and follow-up. Therefore, HCV is not completely cleared during ongoing administration of PegIFN/R otherwise capable of ceasing progression of CHC and virus commonly persists at levels not detectable by the current clinical testing. The findings suggest the need for continued evaluation even after patients achieve undetectable HCV RNA post-treatment.

Viral hepatitis markers in liver tissue in relation to serostatus in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) incidence is increasing in the United States. Hepatitis B virus (HBV) and hepatitis C virus (HCV) are major causes of HCC. Hepatitis infection in patients with HCC is generally diagnosed by serology, which is not always consistent with the presence of HBV and HCV in the liver. The relationship of liver viral status to serostatus in hepatocarcinogenesis is not fully understood.

METHODS

HBV and HCV were evaluated in formalin-fixed, paraffin-embedded liver tissue specimens in a retrospective study of 61 U.S. HCC cases of known serologic status. HBV DNA and HCV RNA were detected by PCR, reverse transcription PCR (RT-PCR), and pyrosequencing, and HBsAg and HBcAg were evaluated by immunohistochemistry.

RESULTS

Viral markers were detected in the liver tissue of 25 of 61 (41%) HCC cases. Tissue viral and serologic status were discordant in 27 (44%) cases, including those with apparent "occult" infection. Specifically, HBV DNA was detected in tissue of 4 of 39 (10%) serum HBsAg (-) cases, including 1 anti-HCV(+) case; and HCV RNA was detected in tissue of 3 of 42 (7%) anti-HCV seronegative cases, including two with serologic evidence of HBV.

CONCLUSIONS

Viral hepatitis, including HBV-HCV coinfection, may be unrecognized in up to 17% of patients with HCC when based on serology alone. Further research is needed to understand the clinical significance of viral makers in liver tissue of patients with HCC in the absence of serologic indices.

IMPACT

The contribution of HBV and HCV to the increasing incidence of HCC in the United States may be underestimated.

Extinction of hepatitis C virus by ribavirin in hepatoma cells involves lethal mutagenesis

Lethal mutagenesis, or virus extinction produced by enhanced mutation rates, is under investigation as an antiviral strategy that aims at counteracting the adaptive capacity of viral quasispecies, and avoiding selection of antiviral-escape mutants. To explore lethal mutagenesis of hepatitis C virus (HCV), it is important to establish whether ribavirin, the purine nucleoside analogue used in anti-HCV therapy, acts as a mutagenic agent during virus replication in cell culture. Here we report the effect of ribavirin during serial passages of HCV in human hepatoma Huh-7.5 cells, regarding viral progeny production and complexity of mutant spectra. Ribavirin produced an increase of mutant spectrum complexity and of the transition types associated with ribavirin mutagenesis, resulting in HCV extinction. Ribavirin-mediated depletion of intracellular GTP was not the major contributory factor to mutagenesis since mycophenolic acid evoked a similar decrease in GTP without an increase in mutant spectrum complexity. The intracellular concentration of the other nucleoside-triphosphates was elevated as a result of ribavirin treatment. Mycophenolic acid extinguished HCV without an intervening mutagenic activity. Ribavirin-mediated, but not mycophenolic acid-mediated, extinction of HCV occurred via a decrease of specific infectivity, a feature typical of lethal mutagenesis. We discuss some possibilities to explain disparate results on ribavirin mutagenesis of HCV.

Persistent hypertransaminasemia in asymptomatic children: A stepwise approach

We aimed to examine the major causes of isolated chronic hypertransaminasemia in asymptomatic children and develop a comprehensive diagnostic flow diagram. A MEDLINE search inclusive of publications throughout August 2012 was performed. We found only a small number of publications that had comprehensively investigated this topic. Consequently, it was difficult to construct a diagnostic flowchart similar to those already available for adults. In children, a “retesting panel” prescription, including gamma-glutamyl transpeptidase and creatine kinase in addition to aminotransferases, is considered a reasonable approach for proficiently confirming the persistence of the abnormality, ruling out cholestatic hepatopathies and myopathies, and guiding the subsequent diagnostic steps. If re-evaluation of physical and historical findings suggests specific etiologies, then these should be evaluated in the initial enzyme retesting panel. A simple multi-step diagnostic algorithm incorporating a large number of possible pediatric scenarios, in addition to the few common to adults, is available. Accurately classifying a child with asymptomatic persistent hypertransaminasemia may be a difficult task, but the results are critical for preventing the progression of an underlying, possibly occult, condition later in childhood or during transition. Given the high benefit/cost ratio of preventing hepatic deterioration, no effort should be spared in diagnosing and properly treating each case of persistent hypertransaminasemia in pediatric patients.

Prevalence of occult hepatitis C virus in egyptian patients with chronic lymphoproliferative disorders

Background. Occult hepatitis C virus infection (OCI) was identified as a new form of Hepatitis C virus (HCV), characterized by undetectable HCV antibodies and HCV RNA in serum, while HCV RNA is detectable in liver and peripheral blood cells only. Aim. The aim of this study was to investigate the occurrence of OCI in Egyptian patients with lymphoproliferative disorders (LPDs) and to compare its prevalence with that of HCV in those patients. Subjects and Methods. The current study included 100 subjects, 50 of them were newly diagnosed cases having different lymphoproliferative disorders (patients group), and 50 were apparently healthy volunteers (controls group). HCV antibodies were detected by ELISA, HCV RNA was detected in serum and peripheral blood mononuclear cells (PBMCs) by reverse transcription polymerase chain reaction(RT-PCR), and HCV genotype was detected by INNO-LiPA. Results. OCI was detected in 20% of patients group, compared to only 4% OCI in controls group. HCV was detected in 26% of patients group with a slightly higher prevalence. There was a male predominance in both HCV and OCI. All HCV positive patients were genotype 4. Conclusion. Our data revealed occurrence of occult HCV infection in Egyptian LPD patients at a prevalence of 20% compared to 26% of HCV.

Patient-derived hepatitis C virus and JFH-1 clones differ in their ability to infect human hepatoma cells and lymphocytes

Hepatitis C virus (HCV) is a hepatotropic virus that also infects cells of the immune system. HCV clones cultivated in human hepatoma Huh-7.5 cells have significantly advanced our understanding of HCV replication and candidate hepatocyte receptors. However, naturally occurring patient-derived HCV, in contrast to the HCV JFH-1 clone, is unable to infect Huh-7.5 cells, while it can replicate in human primary T-cells and selected T-cell lines. To better understand this incongruity, we examined the susceptibility of primary T-cells, PBMCs and T-cell lines to infection with patient-derived HCV, the classical HCV JFH-1 and a cell culture-adapted JFH1T known to be highly infectious to Huh-7.5 cells. We also tested whether Huh-7.5 cells are prone to virus readily infecting T-lymphocytes. The results revealed that while primary T-cells and Molt4 and Jurkat T-cell lines were susceptible to patient-derived HCV, they were resistant to infection with either JFH1T or JFH-1. However, the JFH1T clone interacted more firmly, although non-productively, with the cells than JFH-1. Further, Huh-7.5 cells robustly supported replication of JFH1T but not patient-derived, wild-type virus, despite using highly sensitive detection assays. In conclusion, JFH-1 and JFH1T clones were unable to establish productive infection in human primary T-cells, PBMCs and T-cell lines known to be prone to infection by patient-derived HCV, while Huh-7.5 cells were resistant to infection with naturally occurring virus infecting immune cells. The data showed that the ability to infect lymphocytes is a characteristic of native virus but not laboratory HCV clones.

Prevalence and follow-up of occult HCV infection in an Italian population free of clinically detectable infectious liver disease

Background

Occult hepatitis C virus infection (OCI) is a recently described phenomenon characterized by undetectable levels of HCV-RNA in serum/plasma by current laboratory assays, with identifiable levels in peripheral blood mononuclear cells (PBMCs) and/or liver tissue by molecular tests with enhanced sensitivity. Previous results from our group showed an OCI prevalence of 3.3% in a population unselected for hepatic disease. The present study aimed to evaluate OCI prevalence in a larger cohort of infectious liver disease-free (ILDF) subjects. Clinical follow-up of OCI subjects was performed to investigate the natural history of the infection.

Methods and Findings

439 subjects referred to a Turin Blood Bank for phlebotomy therapy were recruited. They included 314 ILDF subjects, 40 HCV-positive subjects and 85 HBV-positive subjects, of whom 7 were active HBV carriers. Six subjects (4/314 ILDF subjects [1.27%] and 2/7 active HBV carriers [28%]) were positive for HCV-RNA in PBMCs, but negative for serological and virological markers of HCV, indicating OCI. HCV genotypes were determined in the PBMCs of 3/6 OCI subjects two had type 1b; the other had type 2a/2c. OCI subjects were followed up for at least 2 years. After 12 months only one OCI persisted, showing a low HCV viral load (3.73×10¹ UI/ml). By the end of follow-up all OCI subjects were negative for HCV. No seroconversion, alteration of liver enzyme levels, or reduction of liver synthesis occurred during follow-up.

Conclusions

This study demonstrated the existence of OCI in ILDF subjects, and suggested a high OCI prevalence among active HBV carriers. Follow-up suggested that OCI could be transient, with a trend toward the decrease of HCV viral load to levels undetectable by conventional methods after 12–18 months. Confirmation studies with a longer follow-up period are needed for identification of the OCI clearance or recurrence rates, and to characterize the viruses involved.

New perspectives in occult hepatitis C virus infection

Occult hepatitis C virus (HCV) infection, defined as the presence of HCV RNA in liver and in peripheral blood mononuclear cells (PBMCs) in the absence of detectable viral RNA in serum by standard assays, can be found in anti-HCV positive patients with normal serum levels of liver enzymes and in anti-HCV negative patients with persistently elevated liver enzymes of unknown etiology. Occult HCV infection is distributed worldwide and all HCV genotypes seem to be involved in this infection. Occult hepatitis C has been found not only in anti-HCV positive subjects with normal values of liver enzymes or in chronic hepatitis of unknown origin but also in several groups at risk for HCV infection such as hemodialysis patients or family members of patients with occult HCV. This occult infection has been reported also in healthy populations without evidence of liver disease. Occult HCV infection seems to be less aggressive than chronic hepatitis C although patients affected by occult HCV may develop liver cirrhosis and even hepatocellular carcinoma. Thus, anti-HCV negative patients with occult HCV may benefit from antiviral therapy with pegylated-interferon plus ribavirin. The persistence of very low levels of HCV RNA in serum and in PBMCs, along with the maintenance of specific T-cell responses against HCV-antigens observed during a long-term follow-up of patients with occult hepatitis C, indicate that occult HCV is a persistent infection that is not spontaneously eradicated. This is an updated report on diagnosis, epidemiology and clinical implications of occult HCV with special emphasis on anti-HCV negative cases.

Hepatitis B virus and lymphomagenesis: novel insights into an occult relationship

BACKGROUND

Increasing evidence shows that Hepatitis B virus infection associates with B-cell but not T-cell malignancies. It remains unclear (a) whether this association is restricted to discrete subtypes of B-cell neoplasms and (b) if occult hepatitis B virus infection can impact on the risk of B-cell malignancy.

METHODS

We analysed the prevalence of occult hepatitis B virus infection in three age and sex matched groups: patients with multiple myeloma, chronic lymphocytic leukaemia and healthy volunteers (N=80 each group). Hepatitis B virus sequences were detected by PCR in blood mononuclear cells isolated prior to treatment.

RESULTS

Fifteen subjects tested positive for occult hepatitis B virus infection and its distribution significantly favoured chronic lymphocytic leukaemia (p<0.02) over the other groups. No difference in age, gender and proportion of anti-HBc seropositivity was noted according to occult hepatitis B virus infection status. Chronic lymphocytic leukaemia had an odds ratio of 4.6 (95% CI 1.5-13.9) for the presence of occult hepatitis B virus infection in comparison to multiple myeloma and controls. Most occult hepatitis B virus infection cases (10/15, 67%) were detected in completely hepatitis B virus seronegative subjects.

CONCLUSIONS

Our data support a potentially causal relationship for hepatitis B virus in chronic lymphocytic leukaemia but not in multiple myeloma. HBsAg seropositivity alone may bias the study of this association, potentially leading to underestimation. Primary occult hepatitis B virus infection appears the most frequent setting in our patients, extending the clinical relevance of hepatitis B virus vaccination to a preventative measure for B-cell neoplasms.

Hepatitis C virus persistence after sustained virological response to antiviral therapy in patients with or without past exposure to hepatitis B virus

Hepatitis C virus (HCV) and hepatitis B virus (HBV) frequently coinfect and persist long after clinical resolution. We assessed the incidence of low-level (occult) HCV infection (OCI) after sustained virological response (SVR) to standard anti-HCV therapy in individuals with or without past exposure to HBV to recognize whether HBV could influence the prevalence of OCI, HCV level and hepatic histology. Plasma and peripheral blood mononuclear cells (PBMC) were collected from 24 individuals at 6- to 12-month intervals for up to 72 months after SVR. Liver histology was available for nine patients. HCV and HBV genomes were detected with sensitivity <10 genome copies/mL. In individuals without HBV exposure (n = 15), comprehensive analyses of sequential plasma and PBMC samples revealed HCV RNA in all 15 cases (75% plasma and 61% PBMC). In the group with HBV exposure (n = 9), evidenced by circulating anti-HBc and/or HBV DNA detection by a highly sensitive assay, HCV RNA was identified in all cases (83% plasma and 59% PBMC), at levels similar to those in HBV nonexposed individuals. In both groups of patients, most liver biopsies included those reactive for viral genomes displayed low-grade inflammation (8 of 9) and fibrosis (7 of 9). Sequence polymorphisms at the 5`-UTR between PBMC and liver or plasma, as well as circulating HCV virion-like particles, were observed in patients with or without HBV exposure. In conclusion, the prevalence of OCI after SVR is comparable in individuals with or without past exposure to HBV. HCV loads and liver alterations in OCI appear to be unaffected by low-level HBV DNA carriage.

Occult hepatitis C virus infection and its relevance in clinical practice

Hepatitis C virus (HCV) can persist in the liver, lymphoid (immune) cells, and serum of individuals long after an apparently complete therapy-induced or a spontaneous resolution of hepatitis C. This essential asymptomatic infection, called secondary occult HCV infection (OCI), usually occurs in anti-HCV antibody reactive individuals with normal liver function tests. This infection has been identified when the nucleic acid amplification assays of enhanced sensitivity were applied for the detection of HCV genome and its replication. In addition to the secondary OCI, a form of low-level HCV-RNA-positive infection of unknown etiology coinciding with moderately elevated serum liver enzymes and progressing in the absence of anti-HCV detectable by standard clinical assays has been reported. Because of its undefined origin, it can be termed cryptogenic OCI. In this review, the general characteristics of OCI, the ways of its detection and associated controversies, and the potential clinical implications of its existence will be concisely outlined.

Cellular immune responses and occult infection in seronegative heterosexual partners of chronic hepatitis C patients

It is unknown whether hepatitis C virus (HCV)-specific cellular immune responses can develop in seronegative sexual partners of chronically HCV-infected patients and whether they have occult infection. Thirty-one heterosexual partners of patients with chronic HCV were studied, fifteen of them with HCV transmission risks. Ten healthy individuals and 17 anti-HCV seropositive patients, without viremia, were used as controls. Virus-specific CD4+ and CD8+ T-cell responses were measured by flow cytometry against six HCV peptides, situated within the nonstructural (NS) proteins NS3, NS4 and NS5, through intracellular detection of gamma interferon (IFN-γ) or interleukin 4 (IL-4) production and CD69 expression. Sexual partners had a higher production of IFN-γ and IL-4 by CD4+ cells against NS3-p124 (P = 0.003), NS5b-p257 (P = 0.005) and NS5b-p294 (P = 0.012), and CD8+ cells against NS3-p124 (P = 0.002), NS4b-p177 (P = 0.001) and NS3-p294 (P = 0.004) as compared with healthy controls. We observed elevated IFN-γ production by CD4+ T cells against NS5b-p257 (P = 0.042) and NS5b-p294 (P = 0.009) in the sexual partners with HCV transmission risks (sexual, professional and familial altogether) than in those without risks. RNA was extracted from peripheral blood mononuclear cells (PBMC), and detection of HCV-RNA positive and replicative (negative) strands was performed by strand-specific real-time PCR. In four sexual partners, the presence of positive and negative HCV- RNA strands in PBMC was confirmed. Hence, we found an HCV-specific cellular immune response as well as occult HCV infection in seronegative and aviremic sexual partners of chronically HCV-infected patients.

Personalized medicine: new genomics, old lessons

Personalized medicine uses traditional, as well as emerging concepts of the genetic and environmental basis of disease to individualize prevention, diagnosis and treatment. Personalized genomics plays a vital, but not exclusive role in this evolving model of personalized medicine. The distinctions between genetic and genomic medicine are more quantitative than qualitative. Personalized genomics builds on principles established by the integration of genetics into medical practice. Principles shared by genetic and genomic aspects of medicine, include the use of variants as markers for diagnosis, prognosis, prevention, as well as targets for treatment, the use of clinically validated variants that may not be functionally characterized, the segregation of these variants in non-Mendelian as well as Mendelian patterns, the role of gene--environment interactions, the dependence on evidence for clinical utility, the critical translational role of behavioral science, and common ethical considerations. During the current period of transition from investigation to practice, consumers should be protected from harms of premature translation of research findings, while encouraging the innovative and cost-effective application of those genomic discoveries that improve personalized medical care.

Diagnosis of occult hepatitis C without the need for a liver biopsy

The diagnosis of occult hepatitis C virus (HCV) infection is based on the presence of HCV-RNA in the liver. This study aimed to evaluate the use of combining non-invasive assays to diagnose occult HCV. A total of 122 patients with occult HCV (HCV-RNA in the liver without detectable anti-HCV and serum HCV-RNA) and 45 patients with cryptogenic chronic hepatitis (without HCV-RNA in the liver and negative for anti-HCV and serum HCV-RNA) were included. HCV-RNA was tested in peripheral blood mononuclear cells (PBMCs) and in 2 ml of ultracentrifuged serum. Anti-core HCV was examined by a non-commercial enzyme-linked immunosorbent assay. All controls were negative for the three HCV markers studied. Among patients with occult HCV, 36% were anti-core HCV positive, 57% had serum HCV-RNA after ultracentrifugation, and 61% had HCV-RNA in PBMCs. Combining the results of the assays, 91% of the patients were positive for at least one marker. Intrahepatic HCV-RNA load was significantly higher in patients who were positive simultaneously for the three HCV markers than in patients who were negative for all markers (P = 0.006) and than in those with one or two HCV markers (P = 0.039). Replication of HCV in liver was detected more frequently in patients with three (93%, P = 0.002), two (82%, P = 0.001), and one HCV marker (73%, P = 0.011) than in those without markers (27%). In conclusion, testing for all these markers allows diagnosis of occult HCV without the need for a liver biopsy and these assays may help to elucidate the clinical significance of occult HCV infection.

Advances in hepatobiliary pathology: update for 2010

Recent publications on hepatology and hepatic pathology provide a wealth of new information on wideranging topics. Morphologic aspects of liver disease associated with hepatitis B and C viruses, autoimmune hepatitis, and HIV infection were addressed, as was the prevalent problem of nonalcoholic fatty liver disease. Advances in diagnosis and pathogenesis of primary biliary cirrhosis, primary sclerosing cholangitis, and the increasingly complex spectrum of IgG4 hepatobiliary diseases were also reported. The histologic and immunohistochemical features of the rare "calcifying nested stromal-epithelial tumor" of the liver were described in a 9-case series. For benign and malignant liver tumors, immunohistochemistry plays a major diagnostic role, and several recent studies demonstrate the value of immunostains in distinguishing between liver-cell adenoma and focal nodular hyperplasia.