Factors Influencing the Intracellular Concentrations of the Sofosbuvir Metabolite GS-331007 (in PBMCs) at 30 Days of Therapy.

Sofosbuvir (SOF) is an HCV NS5B polymerase inhibitor, and GS-331007 is its major metabolite. The aim of this study was to investigate whether clinical and pharmacological factors could influence GS-331007 intracellular (IC) concentrations in peripheral blood mononuclear cells (PBMCs) associated with a sustained virological response in patients treated with SOF and ribavirin (RBV). Drug levels were analyzed using liquid chromatography at different days of therapy, whereas variants in genes encoding transporters and nuclear factors were investigated using real-time PCR. This study enrolled 245 patients treated with SOF; 245 samples were analyzed for pharmacogenetics and 50 were analyzed for IC pharmacokinetics. The GS-331007 IC concentration at 30 days was associated with its plasma concentration determinate at 30, 60 and 90 days of SOF-therapy and with daclatasvir concentrations at 7 days of therapy. No genetic polymorphism affected IC exposure. In linear multivariate analysis, ledipasvir treatment, baseline albumin and estimated glomerular filtration rate were significant predictors of IC exposure. This study presents data on an IC evaluation in a cohort of patients treated with SOF, also considering pharmacogenetics. These results could be useful for regions where SOF-RBV treatment is considered the standard of care; moreover, they could further deepen the knowledge of IC exposure for similar drugs in the future.

The hepatitis D virus in Italy. A vanishing infection, not yet a vanished disease.

INTRODUCTION: Hepatitis D Virus (HDV) infection is vanishing in Italy. It is therefore believed that hepatitis D is no longer a medical problem in the domestic population of the country but remains of concern only in migrants from HDV-endemic areas. OBJECTIVES: To report the clinical features and the medical impact of the residual domestic HDV infections in Italy. METHODS: From 2010 to 2019, one hundred ninety-three first-time patients with chronic HDV liver disease attended gastroenterology units in Torino and San Giovanni Rotondo (Apulia); 121 were native Italians and 72 were immigrants born abroad. For this study, we considered the 121 native Italians in order to determine their clinical features and the impact of HDV disease in liver transplant programs. RESULTS: At the last observation the median age of the 121 native Italians was 58 years. At the end of the follow-up, the median liver stiffness was 12.0 kPa (95% CI 11.2-17.4), 86 patients (71.1%) had a diagnosis of cirrhosis; 80 patients (66.1%) remained HDV viremic. The ratio of HDV to total HBsAg transplants varied from 38.5% (139/361) in 2000-2009 to 50.2% (130/259) in 2010-2019, indicating a disproportionate role of hepatitis D in liver transplants compared to the minor prevalence of HDV infections in the current scenario of HBsAg-positive liver disorders in Italy. CONCLUSION: Though HDV is vanishing in Italy, a legacy of ageing native-Italian patients with advanced HDV liver disease still represents an important medical issue and maintains an impact on liver transplantation.

Cooperative Role of Thrombopoietin and Vascular Endothelial Growth Factor-A in the Progression of Liver Cirrhosis to Hepatocellular Carcinoma.

Primary thrombopoietic mediator thrombopoietin (THPO) is mainly produced by the liver; it may act as a growth factor for hepatic progenitors. Principal angiogenesis inducer vascular endothelial growth factor-A (VEGF-A) is critical for the complex vascular network within the liver architecture. As a cross-regulatory loop between THPO and VEGF-A has been demonstrated in the hematopoietic system, the two growth factors were hypothesized to cooperatively contribute to the progression from liver cirrhosis (LC) to hepatocellular carcinoma (HCC). The mRNA and protein expression levels of THPO, VEGF-A, and their receptors were examined, compared, and correlated in paired cancerous and LC tissues from 26 cirrhosis-related HCC patients, using qRT-PCR and immunohistochemistry. THPO and VEGF-A were alternatively silenced by small interfering RNA (siRNA) in human liver cancer cell lines Huh7 and HepG2. THPO and VEGF-A expressions significantly increased in tumor versus LC tissues. HCC and paired LC cells expressed similar levels of THPO receptor (R), whereas vascular endothelial growth factor receptor (VEGFR) -1 and VEGFR-2 levels were higher in HCC than in corresponding LC tissue samples. A significant linear correlation emerged between THPO and VEGF-A transcripts in HCC and, at the protein level, THPO and THPOR were significantly correlated with VEGF-A in tumor tissues. Both HCC and LC expressed similar levels of gene and protein hypoxia inducible factor (HIF)-1α. Positive cross-regulation occurred with the alternative administration of siRNAs targeting THPO and those targeting VEGF-A in hypoxic liver cancer cell lines. These results suggest THPO and VEGF-A might act as interdependently regulated autocrine and/or paracrine systems for cellular growth in HCC. This might be clinically interesting, since new classes of THPOR agonistic/antagonistic drugs may provide novel therapeutic options to correct the frequent hemostatic abnormality seen in HCC patients.

Incremental value of HBcrAg to classify 1582 HBeAg-negative individuals in chronic infection without liver disease or hepatitis.

BACKGROUND: An accurate, single-point differential diagnosis between HBeAg-negative infection (ENI) and chronic hepatitis B (CHB) is an unmet need. AIMS: To assess the diagnostic value of the new hepatitis B core-related antigen (HBcrAg) assay. METHODS: A retrospective anonymised data analysis was performed in a multicentre European (nine centres and six countries) cohort of 1582 consecutive HBsAg-positive/HBeAg-negative subjects classified according to EASL guidelines as: 550-CHB, 710-ENI and 322-GZ (grey-zone, HBV-DNA <20 000 IU/mL). RESULTS: Mean age was 44 (±13.2 y), 59% were men; HBV genotypes were 15% A, 2% B, 2% C, 45% D, 9% E, 1% F and 26% unknown. Median HBV-DNA serum levels were 2.2 (1.5-2.7), 3.5 (3.2-3.8) and 5.6 (4.8-6.6) logIU/mL in ENI, GZ and CHB, P < 0.0001. HBsAg serum levels (HBsAgsl) were comparable in CHB and GZ, but lower in ENI (2.9 [2.1-3.6] logIU/mL), P < 0.0001. HBcrAg serum levels (HBcrAgsl) were <3 logU/mL in 90.7% (644/710) ENI, 75.2% (242/322) GZ and 4.7% (26/550) CHB (P < 0.0001). Median HBcrAgsl were 4.8 (3.9-5.7), 2.5 (2.0-2.9) and 2.0 (2.0-2.5) logU/mL in CHB, GZ and ENI, (P < 0.0001). ROC-AUCs for HBcrAg and HBsAg were 0.968 (95% CI, 0.958-0.977) and 0.732 (95% CI, 0.704-0.760) respectively. The optimal HBcrAgsl cut-off to distinguish CHB from ENI was 3.14 logU/mL (95% CI, 3.02-3.25, 91% SE, 93% SP and 92.4% DA). HBcrAgsl were associated with HBV genotypes (P < 0.001, one-way ANOVA) but using genotype-specific cut-offs, HBcrAg DA remained unchanged with overlapping 95% CI. CONCLUSION: The HBcrAg assay showed high diagnostic performance in the accurate single-point identification of patients with HBeAg-negative CHB, independently of HBV genotype. This should prompt future prospective studies to confirm its diagnostic role in clinical practice.

Analytical and clinical evaluation of a novel assay for anti-HBc IgG measurement in serum of subjects with overt and occult HBV infection.

OBJECTIVES: We assessed the analytical and clinical performance of the Lumipulse® G HBcAb-N (Fujirebio, Japan) assay for IgG antibodies to hepatitis B core antigen (anti-HBc IgG) measurement in serum of subjects with overt and occult HBV infection (OBI). MATERIALS/METHODS: Serum anti-HBc IgG was assessed in 181 anti-HBc-positive subjects: 119 chronic hepatitis B (CHB) patients in different infection phases and 62 subjects (35 CHB and 27 OBI) with available liver specimens for HBV covalently-close-circular (ccc) DNA analysis. RESULTS: The anti-HBc IgG assay showed a linear dynamic range (R2 = 0.9967); lower limit of detection and quantitation were 0.5 IU/mL and 0.8 IU/mL. Reproducibility was 4.9% and accuracy 98.7%. Anti-HBc IgG levels varied according to HBV infection phase, linearly declined during antiviral treatment and resulted correlated to intrahepatic HBV cccDNA (r = 0.752, P < 0.001). CONCLUSIONS: The quantitative anti-HBc IgG assay exhibited appropriate analytical performance and may represent a diagnostic complement in CHB patients and OBI subjects.

The association between education level and chronic liver disease of any etiology.

BACKGROUND: The potential link between educational level and chronic liver diseases (CLD) were explored using the mortality records of liver cirrhosis, which lack accuracy and are unable to identify the different etiological factors of liver cirrhosis. Information on the association of low educational level with the severity of CLD is lacking. AIM: To evaluate the potential association linking education level to etiology and clinical stage of CLD cases. METHODS: Consecutive enrolment of 11,107 subjects with CLD aged≥18 years prospectively recruited in two national surveys in 2001 and 2014 at one of the participating Italian liver units throughout the country. Subjects were pooled in two groups: low education level (less than high school) and high education level (completed high school or beyond). The association of demographic, etiological, and clinical stage of subjects with educational level was assessed using logistic regression analysis. In the analysis low educational level was the outcome variable. RESULTS: A total of 11,107 subjects born in Italy (mean age 55.5 years, sex ratio 1.5) were evaluated. Multiple logistic regression analysis shows that chronic HCV infection (O.R.1,38:95%,C.I.1.23-1.55), risky alcohol intake (O.R.1.96;95%,C.I.1.73-2.21) and liver cirrhosis (O.R.1.65;95%,C.I.1.46-1.85) all resulted independently associated with less than a completed high school education. HBV infection resulted independently associated with high education level (O.R.0.74;95%,C.I.0.64-0.86), reflecting changes in HBV modes of transmission in recent decades. No association was found with CLD related to non-alcoholic fatty liver disease (O.R.1.03;95%, C.I.0.81-1.30). CONCLUSIONS: These findings show an independent association linking education level with viruses and alcohol-related CLD. Low educational level is associated with the severity of CLD.

Clinical outcomes in chronic hepatitis C long-term responders to pre-direct antiviral agents: a single-center retrospective study.

BACKGROUND: Obesity, type 2 diabetes (T2D), dyslipidemia, arterial hypertension as well as hepatic steatosis (HS) are common conditions that can affect clinical outcomes of patients with chronic hepatitis C (CHC) who achieved sustained virologic response (SVR). The aim of this study was to assess the impact of metabolic cofactors on the occurrence of clinical events during follow-up (FU) in a group of CHC long-term responders (LTRs) to interferon- (IFN) based therapy. METHODS: A total of 5172 medical records of CHC patients enrolled from 1990 to 2011 were examined; 1034 of 5172 (20%) patients were treated with IFN-based therapy and 382 of 1034 (37%) of them achieved SVR. A total of 188 (49%) LTRs underwent liver biopsy before antiviral treatment. Data on liver and cardiometabolic events such as cirrhosis and its complications, hepatocellular carcinoma, coronary artery disease, arterial hypertension, impaired fasting glucose (IFG)/type 2 diabetes (T2D) and dyslipidemia, were collected over time. RESULTS: The mean age of the whole cohort was 46±12 years and 114/188 (61%) patients were males. HS was found in 82 of 188 (43.6%) patients and most of them were infected by HCV genotype 3a. The prevalence of obesity, IFG/T2D, dyslipidemia and arterial hypertension was 4.3%, 6.9%, 37.2%, and 5.9%, and was similarly distributed among patients with and without HS. Cirrhosis was histologically diagnosed in 18 of 188 (9.6%) patients. After a median follow-up of 11 years (range 3-21 years), the cumulative incidence of cardiovascular events, IFG/T2D and dyslipidemia was higher in CHC-LTRs who had HS at baseline compared to those without HS (1.2%, 2.3%, and 3.0% vs. 0.4%, 0.8%, and 2.5%, respectively). At multivariable Cox regression analysis, HS was significantly associated to the development of cardiovascular events and IFG/T2D (HR=5.2, 95% CI: 1.3-20.7, P=0.019, and HR=2.6, 95% CI: 1.1-6.2, P=0.027, respectively). CONCLUSIONS: In CHC-LTRs, HS at baseline may predispose to the development of cardiovascular events and T2D during follow-up emphasizing the importance of an accurate counseling in order to prevent extra-hepatic complications.

Decreasing role of HCV and HBV infections as aetiological factors of hepatocellular carcinoma in Italy.

BACKGROUND: The epidemiology of hepatocellular carcinoma (HCC) is characterized by a dynamical temporal trend of well-established and emerging risk factors. METHODS: We evaluated the temporal trend of aetiological factors of HCC over the last two decades in Italy. HCC cases were recruited from two previously published national studies in 1996 and in 2008 and HCC cases were also enlisted from two national surveys in 2001 and in 2014 enrolling consecutive subjects with chronic liver disease (CLD) referring to more than 80 liver units scattered all over the country for a 6-month period. RESULTS: Out of the 9997 subjects with CLD recruited in 2001 and the 2408 recruited in 2014, 3.3% and 5.7% (P < 0.001), respectively, had HCC. The temporal trend of HBsAg -/HCV + HCC cases significantly linearly decreased from 71.1% in 1996 to 57.2% in 2014 (P < 0.001). Conversely, that of virus-negative cases significantly linearly increased from 12.1% to 28.3% (P < 0.001). The proportion of HBV-related HCC cases showed a steady low rate, reflecting the reduced endemicity of the infection in Italy. The proportion of HCC with compensated cirrhosis (i.e., Child-Pugh A) linearly increased over time from 55.6% in 1996 to 76.0% in 2014 (P < 0.001) reflecting the growing effectiveness of semi-annual ultrasound surveillance for early detection of HCC. CONCLUSION: In conclusion, with decreasing viral aetiology, an overall decrease in the incidence of HCC might be expected in the future. The proportion of metabolic diseases is conversely increasing being considered as an aetiology. The growing prevalence of metabolic disorders in the general population may further increase this trend in the years to come.

Mutations in Hepatitis D Virus Allow It to Escape Detection by CD8+ T Cells and Evolve at the Population Level.

BACKGROUND & AIMS: Hepatitis D virus (HDV) superinfection in patients with hepatitis B virus (HBV) is associated with rapid progression to liver cirrhosis and hepatocellular carcinoma. Treatment options are limited, and no vaccine is available. Although HDV-specific CD8+ T cells are thought to control the virus, little is known about which HDV epitopes are targeted by virus-specific CD8+ T cells or why these cells ultimately fail to control the infection. We aimed to define how HDV escapes the CD8+ T-cell-mediated response. METHODS: We collected plasma and DNA samples from 104 patients with chronic HDV and HBV infection at medical centers in Europe and the Middle East, sequenced HDV, typed human leukocyte antigen (HLA) class I alleles from patients, and searched for polymorphisms in HDV RNA associated with specific HLA class I alleles. We predicted epitopes in HDV that would be recognized by CD8+ T cells and corresponded with the identified virus polymorphisms in patients with resolved (n = 12) or chronic (n = 13) HDV infection. RESULTS: We identified 21 polymorphisms in HDV that were significantly associated with specific HLA class I alleles (P < .005). Five of these polymorphisms were found to correspond to epitopes in HDV that are recognized by CD8+ T cells; we confirmed that CD8+ T cells in culture targeted these HDV epitopes. HDV variant peptides were only partially cross-recognized by CD8+ T cells isolated from patients, indicating that the virus had escaped detection by these cells. These newly identified HDV epitopes were restricted by relatively infrequent HLA class I alleles, and they bound most frequently to HLA-B. In contrast, frequent HLA class I alleles were not associated with HDV sequence polymorphisms. CONCLUSIONS: We analyzed sequences of HDV RNA and HLA class I alleles that present epitope peptides to CD8+ T cells in patients with persistent HDV infection. We identified polymorphisms in the HDV proteome that associate with HLA class I alleles. Some variant peptides in epitopes from HDV were only partially recognized by CD8+ T cells isolated from patients; these could be mutations that allow HDV to escape the immune response, resulting in persistent infection. HDV escape from the immune response was associated with uncommon HLA class I alleles, indicating that HDV evolves, at the population level, to evade recognition by common HLA class I alleles.

Geographical pattern of chronic liver diseases in Italy: Results from two pooled national surveys.

BACKGROUND: The information on the geographical characteristics of chronic liver diseases (CLD) in Italy is out-dated. AIM: To provide up-dated information on the geographical pattern of patients with CLD born in Italy. METHODS: Patients with CLD were enrolled in two national surveys performed in 2001 and 2014, which prospectively recruited subjects aged ≥18 years referring to Italian liver units located throughout the country that apply a similar clinical approach and analytical methods. RESULTS: The total number of patients enrolled was 11,676. Alcohol-related CLD was more frequently observed in northern/central areas (25.0% vs. 20.7%, p < .001), while HBV-related (15.4% vs. 13.3%, p = .02) and HCV-related (71.2% vs. 67.1%, p < .001) CLD prevailed in southern areas/main islands (Sicily and Sardinia). These differences were stable over time. Liver cirrhosis without HCC was diagnosed more frequently in southern area/islands than in northern/central areas (23.7% vs. 18.8%, p < .01). Moreover, an increased proportion over time of patients with cirrhosis without HCC was observed both in northern/central areas (17.3% vs. 27.4%, p < .01) and in southern area/islands (22.6% vs. 27.9%, p < .01). CONCLUSIONS: These up-dated findings show different geographical patterns of CLD in Italy, reflecting different behavioural habits and socio-economic conditions across the country. They may be useful to apply more adequate preventive measures and to allocate economic resources.

The burden of HBV infection in HCV patients in Italy and the risk of reactivation under DAA therapy.

BACKGROUND: There is increasing awareness of HBV reactivation in HCV-RNA-positive/HBV-coinfected patients with chronic liver disease (CLD) treated with oral direct-acting antivirals (DAAs). AIM: To provide figures on the prevalence of HBV markers in HCV-RNA-positive subjects in Italy, where these findings are lacking. METHODS: All subjects aged ≥18 years with CLD consecutively referring to Italian liver units located throughout country were prospectively enrolled in two national surveys in 2001 and 2014. RESULTS: The total number of HCV-RNA-positive cases was 6984; 356 (5.1%) subjects vaccinated against HBV were excluded. A total of 6628 cases were evaluated. The prevalence rates of HBsAg, isolated anti-HBc and anti-HBc/anti-HBs-positivity were 2.9%, 8.1% and 14.7%, respectively. Among the estimated one million HCV-RNA-positive subjects in Italy, a substantial number of subjects are at risk of HBV reactivation due to DAA therapy. The prevalence of liver cirrhosis was higher than that of CLD in HBsAg-positive subjects (4.4% vs. 2.6%, p < 0.01) but not in those positive for other HBV markers. CONCLUSIONS: These findings outline the burden of HBV markers among HCV-RNA-positive subjects in Italy, where in 2017 reimbursement for DAA therapy by the National Health System became universal for all patients with chronic HCV infection. HBV vaccination coverage should be greatly extended, since nearly two thirds of subjects in this study resulted negative for any HBV marker.

Serum zonulin in patients with inflammatory bowel disease: a pilot study.

BACKGROUND: In recent years it has been supposed that impaired intestinal permeability represents an early event preceding the onset of inflammatory bowel disease (IBD). Since zonulin has been proposed as a biomarker of intestinal permeability, we investigated its role in patients with IBD and the correlation between serum and fecal zonulin. METHODS: A total of 118 IBD patients (86 Crohn's disease [CD] and 32 ulcerative colitis [UC]) and 23 healthy controls (HC) were prospectively enrolled. A serum sample was collected for all the subjects included in the study. A stool specimen collected in the same day of blood drawing was available for a subgroup of 33 IBD patients. Serum and fecal zonulin were tested by ELISA. Non-parametric statistical tests were used for data analysis. RESULTS: Serum zonulin concentration was higher in IBD patients compared to HC (34.5 [26.5-43.9] ng/mL vs. 8.6 [6.5-12.0] ng/mL, P<0.001) showing an area under the curve of 0.98 for their discrimination. No difference in serum zonulin concentration was observed between patients with CD and those with UC (P=0.074). An inverse correlation was observed between serum zonulin concentration and disease duration (rs=-0.30, P=0.001); no correlation was observed between serum and fecal zonulin (rs=0.15, P=0.394). CONCLUSIONS: Serum zonulin is highly sensitive for the evaluation of intestinal permeability in IBD patients. There is no correlation between zonulin values in serum and feces.

Characteristics and Changes over Time of Alcohol-Related Chronic Liver Diseases in Italy.

Introduction: To evaluate the characteristics of alcohol-related chronic liver disease (CLD) in Italy and their potential changes over time. Patients and Methods: Subjects with CLD were enrolled in two national surveys performed in 2001 and in 2014 in Italy. The two surveys prospectively recruited patients aged ≥ 18 years referring to more than 80 Italian liver units scattered all over the country using similar clinical approach, analytical methods, and threshold of risky alcohol intake definition (≥ 3 units/day in men and ≥ 2 units/day in women). Results: Out of 12,256 enrolled subjects, 2,717 (22.2%) reported a risky alcohol intake. Of them, anti-HCV positive was observed in 48.3% of subjects. The overall sex ratio (M/F) was 3.1, decreasing from 3.8 in 2001 to 1.3 in 2014. Women were significantly older than men (58.9 versus 53.1 years; p < 0.01) and an increasing ageing over time was observed in both sexes. The proportion of subjects with liver cirrhosis increased over time in both sexes, and decompensated stage (Child B or C) was detected in 55.9% of cases in 2001 and 46.0% in 2014. Conclusions: Risky alcohol intake plays a role in more than one-fifth of CLD in Italy, with a shift over time towards an older age and a more severe liver disease stage. These data put alcohol back in the spotlight with an important role in CLD in the years to come in Italy.

Performance of protein induced by vitamin K absence or antagonist-II assessed by chemiluminescence enzyme immunoassay for hepatocellular carcinoma detection: a meta-analysis.

OBJECTIVES: In the setting of surveillance for hepatocellular carcinoma (HCC) detection, the use of serum biomarkers in addition to ultrasonography (US) is still a matter of debate. Hence, we performed a meta-analysis to evaluate the diagnostic accuracy of protein induced by vitamin K absence or antagonist-II (PIVKA-II) and alpha-fetoprotein (AFP) alone or in combination for HCC detection in patients at risk of tumor development. MATERIALS AND METHODS: We performed a systematic search in PubMed and Scopus database for original articles published in English from 2011 to 2017, investigating the accuracy of PIVKA-II alone or in combination with AFP (reported as area under the curve [AUC]) for HCC detection among patients at risk of tumor development. Furthermore, we focused on studies in which serum PIVKA-II was assessed by highly sensitive chemiluminescence immunoassay (CLEIA). RESULTS: A total of 11 studies (873 patients with HCC and 1244 patients with advanced liver disease/cirrhosis) were included in the meta-analysis. The weighted summary AUC (sAUC) of PIVKA-II and AFP for the discrimination between patients with HCC and those without was 0.791 (0.746-0.837) and 0.767 (0.732-0.803), respectively. The combination of PIVKA-II + AFP results in a sAUC of 0.859 (0.837-0.882). The performance for HCC detection of PIVKA-II + AFP was significantly superior to each biomarker used alone (ΔsAUC = 0.068, p = .032 and ΔsAUC = 0.092, p < .001, respectively). CONCLUSION: In clinical practice, the use of PIVKA-II + AFP in addition to US examination may improve the effectiveness of surveillance among patients at risk for HCC development.

Quantitation of HBV cccDNA in anti-HBc-positive liver donors by droplet digital PCR: A new tool to detect occult infection.

BACKGROUND & AIMS: The accurate diagnosis of occult hepatitis B virus (HBV) infection (OBI) requires the demonstration of HBV DNA in liver biopsies of hepatitis B surface antigen-negative individuals. However, in clinical practice a latent OBI is deduced by the finding of the antibody to the hepatitis B core antigen (anti-HBc). We investigated the true prevalence of OBI and the molecular features of intrahepatic HBV in anti-HBc-positive individuals. METHODS: The livers of 100 transplant donors (median age 68.2 years; 64 males, 36 females) positive for anti-HBc at standard serologic testing, were examined for total HBV DNA by nested-PCR and for the HBV covalently closed circular DNA (HBV cccDNA) with an in-house droplet digital PCR assay (ddPCR) (Linearity: R2 = 0.9998; lower limit of quantitation and detection of 2.4 and 0.8 copies/105 cells, respectively). RESULTS: A total of 52% (52/100) of the individuals studied were found to have OBI. cccDNA was found in 52% (27/52) of the OBI-positive, with a median 13 copies/105 cells (95% CI 5-25). Using an assay specific for anti-HBc of IgG class, the median antibody level was significantly higher in HBV cccDNA-positive than negative donors (17.0 [7.0-39.2] vs. 5.7 [3.6-9.7] cut-off index [COI], respectively, p = 0.007). By multivariate analysis, an anti-HBc IgG value above 4.4 COI was associated with the finding of intrahepatic HBV cccDNA (odds ratio 8.516, p = 0.009); a lower value ruled out its presence with a negative predictive value of 94.6%. CONCLUSIONS: With a new in-house ddPCR-based method, intrahepatic HBV cccDNA was detectable in quantifiable levels in about half of the OBI cases examined. The titer of anti-HBc IgG may be a useful surrogate to predict the risk of OBI reactivation in immunosuppressed patients. LAY SUMMARY: The covalently closed circular DNA (cccDNA) form of the hepatitis B virus (HBV) sustains the persistence of the virus even decades after resolution of the symptomatic infection (occult HBV infection). In the present study we developed a highly sensitive method based on droplet digital PCR technology for the detection and quantitation of HBV cccDNA in the liver of individuals with occult HBV infection. We observed that the amount of HBV cccDNA may be inferred from the titer in serum of the IgG class antibody to the hepatitis B core antigen. The quantitation of this antibody may represent a surrogate to determine which patients are at the highest risk of HBV reactivation following immunosuppressive therapies.

Amino Acid Substitutions within HLA-B*27-Restricted T Cell Epitopes Prevent Recognition by Hepatitis Delta Virus-Specific CD8+ T Cells.

Virus-specific CD8 T cell response seems to play a significant role in the outcome of hepatitis delta virus (HDV) infection. However, the HDV-specific T cell epitope repertoire and mechanisms of CD8 T cell failure in HDV infection have been poorly characterized. We therefore aimed to characterize HDV-specific CD8 T cell epitopes and the impacts of viral mutations on immune escape. In this study, we predicted peptide epitopes binding the most frequent human leukocyte antigen (HLA) types and assessed their HLA binding capacities. These epitopes were characterized in HDV-infected patients by intracellular gamma interferon (IFN-γ) staining. Sequence analysis of large hepatitis delta antigen (L-HDAg) and HLA typing were performed in 104 patients. The impacts of substitutions within epitopes on the CD8 T cell response were evaluated experimentally and by in silico studies. We identified two HLA-B*27-restricted CD8 T cell epitopes within L-HDAg. These novel epitopes are located in a relatively conserved region of L-HDAg. However, we detected molecular footprints within the epitopes in HLA-B*27-positive patients with chronic HDV infections. The variant peptides were not cross-recognized in HLA-B*27-positive patients with resolved HDV infections, indicating that the substitutions represent viral escape mutations. Molecular modeling of HLA-B*27 complexes with the L-HDAg epitope and its potential viral escape mutations indicated that the structural and electrostatic properties of the bound peptides differ considerably at the T cell receptor interface, which provides a possible molecular explanation for the escape mechanism. This viral escape from the HLA-B*27-restricted CD8 T cell response correlates with a chronic outcome of hepatitis D infection. T cell failure resulting from immune escape may contribute to the high chronicity rate in HDV infection.IMPORTANCE Hepatitis delta virus (HDV) causes severe chronic hepatitis, which affects 20 million people worldwide. Only a small number of patients are able to clear the virus, possibly mediated by a virus-specific T cell response. Here, we performed a systematic screen to define CD8 epitopes and investigated the role of CD8 T cells in the outcome of hepatitis delta and how they fail to eliminate HDV. Overall the number of epitopes identified was very low compared to other hepatotropic viruses. We identified, two HLA-B*27-restricted epitopes in patients with resolved infections. In HLA-B*27-positive patients with chronic HDV infections, however, we detected escape mutations within these identified epitopes that could lead to viral evasion of immune responses. These findings support evidence showing that HLA-B*27 is important for virus-specific CD8 T cell responses, similar to other viral infections. These results have implications for the clinical prognosis of HDV infection and for vaccine development.