Kinetics and predictive value of HBcrAg, HBV RNA and anti-HBc during bulevirtide treatment of chronic HDV-infected patients.

The entry inhibitor bulevirtide (BLV) is a new treatment option for patients with chronic hepatitis D virus (HDV) infection and compensated liver disease. The aim of this study was to investigate the kinetic and predictive value of markers reflecting HBV cccDNA transcriptional activity and host immune response activity during BLV treatment in a real-life cohort of HDV infected patients. Levels of HDV RNA, HBV RNA, hepatitis B core related antigen (HBcrAg) and hepatitis B core antibodies (anti-HBc) were measured in 16 patients before (BL), after three (3M) and six (6M) months of treatment with BLV. All patients received nucleos(t)ide analogue treatment. HDV RNA declined in all patients during treatment. 38% (6/16) showed ≥ 2 log HDV RNA decline from BL to 6M and 11 patients (69%) normalized ALT levels. HBV RNA levels were low and only detectable in two to four patients. HBcrAg levels declined in 75% (12/16) of patients. Median HBcrAg levels declined significantly from BL to 6M (3.75 logU/ml (IQR 2.93-4.78) vs. 3.4 logU/ml (IQR 2-4.68), p=0.002). A similar trend was shown for anti-HBc between BL and 6M. Levels of HBcrAg or anti-HBc did not differ significantly between patients with or without ≥ 2 log HDV RNA decline from BL to 6M.After 6 months treatment with BLV, levels of HBcrAg showed a significant decline, while HBV RNA and anti-HBc levels did not change. Reduction of HBV cccDNA transcriptional activity and immunological effects of antiviral treatment might explain these changes.

Characterization of hepatitis virus co-infections in a cohort of immigrants living in southern Italy.

To characterize viral hepatitis co-infections in a cohort of immigrants living in southern Italy. In a prospective multicenter study, all undocumented immigrants and low-income refugees consecutively evaluated for a clinical consultation at one of the five first-level clinical centers in southern Italy from January 2012 to February 2020 were enrolled. All subjects included in the study were screened for hepatitis B surface antigen (HBsAg), anti-hepatitis C virus (HCV) and anti-HIV; the HBsAg-positive were screened also for anti-delta. Of the 2923 subjects enrolled, 257 (8%) were HBsAg-positive alone (Control group B), 85 (2.9%) only anti-HCV-positive (Control group C), 16 (0.5%) HBsAg/anti-HCV-positive (Case group BC), and 8 (0.2%) HBsAg/anti-HDV-positive (Case group BD). Moreover, 57 (1.9%) subjects were anti-HIV-positive. HBV-DNA positivity was found less frequently in the 16 subjects in Case group BC (43%) and in the 8 in Case group BD (12.5%) than in the 257 in Control group B (76%; p = 0.03 and 0.0000, respectively). Similarly, HCV-RNA positivity was more frequent in Case group BC than in Control group C (75% vs. 44.7% p = 0.02). The subjects in Group BC had a lower prevalence of asymptomatic liver disease (12.5%) than Control group B (62.2%, p = 0.0001) and Control group C (62.3%, p = 0.0002). Conversely, liver cirrhosis was more frequently identified in Case group BC (25%) than in Control groups B and C (3.11% and 2.35%, p = 0.0000 and 0.0004, respectively). The present study contributes to the characterization of hepatitis virus co-infections in the immigrant population.

HBV S antigen evolution in the backdrop of HDV infection affects epitope processing and presentation.

INTRODUCTION: HBV can evolve under selection pressure exerted by drugs and/or host immunity, resulting in accumulation of escape mutations that can affect the drug or the immune activity. Hepatitis delta virus (HDV) coinfection is also known to exert selection pressure on HBV, which leads to selective amplification of certain mutations, especially in genes that are required for HDV pathogenesis, such as HBsAg. However, little is known about the function of these mutations on HBV or HDV life cycle. The purpose of this study is to determine mutations selectively amplified in the backdrop of HDV, and how these mutations affect processing of CD4- and CD8-T cell epitopes. METHODS: HBsAg was successfully amplified from 49/50 HBV mono- and 36/50 coinfected samples. The sequences were used to identify mutations specific to each study group, followed by an in silico analysis to determine the effect of these mutations on (1) proteasomal degradation, (2) MHC-I and MHC-II biding, and (3) processing of T-cell epitopes. RESULTS: HBV-HDV coinfected sequences exhibited certain unique mutations in HBsAg genes. Some of these mutations affected the generation of proteasomal sites, binding of HBsAg epitopes to MHC-I and -II ligands, and subsequent generation of T- cell epitopes. CONCLUSION: These observations suggest that HBV selectively amplifies certain mutations in the backdrop of HDV coinfection. Selective amplification of these mutations at certain strategic locations might not only enable HBV to counteract the inhibitory effects of HDV on HBV replication but also facilitate its survival by escaping the immune response.

HDV infection in immigrant populations.

AIMS: Little data have been published so far on the epidemiological aspects of hepatitis D virus (HDV) infection in immigrant populations and even poorer is the information on the virological, phylogenetic, and clinical aspects of this infection in these populations. This review article, aimed primarily at physicians caring for immigrants, summarizes the information available on HDV infection and analyzes data on this topic concerning the immigrant populations. METHODS AND RESULTS: The prevalence of HDV infection in HBsAg-positive immigrants varies according to the country of origin. For example, in immigrants from sub-Saharan Africa, this prevalence is higher in those born in Equatorial Guinea (24.4%) than those from other African countries (10.3%). The epidemiological impact of HDV infection linked to migratory flows is a function of the different endemicity between countries of origin and countries in which a new existence has been established. This impact is high when immigrants from areas endemic to HDV infection (eg, Equatorial Guinea) settle in areas of low endemicity (eg, Germany or England, with a prevalence of around 4%), while the impact is lesser or nonexistent if the migratory flows are directed toward countries with intermediate endemicity (eg, Italy and Greece, with a prevalence of around 10%). CONCLUSION: This impact of immigration on HDV epidemiology can be strong when HDV endemicity is high in the country of origin and low in the host country and slight when immigrants move to high or medium endemic countries.

HBV/HDV co-infection in the Western Brazilian Amazonia: an intriguing mutation among HDV genotype 3 carriers.

HDV infection still remains a serious public health problem in Amazonia. There are few data regarding the biomolecular aspects of HBV/HDV co-infection in this region. We studied 92 patients HBsAg(+) /anti-HDV IgG(+) followed at the Hepatitis Referral Centers of Porto Velho (RO), Rio Branco and Cruzeiro do Sul (AC), Brazil, from March 2006 to March 2007 for whom the HDV and/or the HBV genotype could be determined. The HDV genotype could be determined in 90 patients, while the HBV genotypes could be positively determined in 74. HBV subgenotype F2 is the most prevalent (40.2%), followed by the subgenotypes A1 (15.2%) and D3 (8.7%), while 16.4% were other subgenotypes or genotypes, 4.3% were discordant and 15.2% were unamplifiable. Surprisingly, HDV genotype 3 (HDV-3) was found in all of the HBV/HDV-infected patients that could be genotyped for HDV, confirming that HDV-3 can associate with non-F HBV genotypes. However, a HDV-3 mutant was found in 29.3% of patients and was more frequently associated with non-F HBV genotypes (P < 0.001) than were nonmutant strains, suggesting that the mutation may facilitate association of HDV-3 with non-F HBV genotypes.

Systemic cytokine and viral antigen-specific responses in hepatitis D virus RNA positive versus HDV RNA negative patients.

Background: Hepatitis B virus (HBV)/Hepatitis D Virus (HDV) co-infection increases the risk of severe liver disease compared to HBV mono-infection. Adaptive immune responses to HDV are weakly detectable, and the involvement of innate immunity in the progression of HDV-related liver fibrosis is suggested. We hypothesize that an overall innate immune activation in HBV/HDV co-infection plays a role in liver disease progression and also impacts virus specific T cell response. Methods: Sixteen HBV/HDV-co-infected-patients (median age 42y/7F/6 Asian/4 White/6 Black/15 HBeAg-) and 8 HBV monoinfected-patients (median age 39y/4F/4 Asian/3 Black/1 White/HBeAg-) with median follow-up of 5 years were enrolled. Liver fibrosis was assessed by liver stiffness measurement (LSM, FibroScan®). Proliferation of CD3 + CD4+ T cells in response to viral antigens using CFSE assays and cytokine secreting monocytes was analyzed by flow cytometry. Results: Of 16 HBV/HDV, 11 were HDV-RNA+ (HBV-DNA 0-1,040 IU/mL), 5/11 Interferon (IFN) + Nucleos/tide Analog (NA), 3/11 NA monotherapy, median ALT 77 U/L at the time of sample collection, median LSM of 9.8. In 5 HDV RNA-, median HBV DNA 65 IU/mL, 4/5 prior IFN and/or NA, ALT 31 U/L, and median LSM 8.5 kPa. In 8 HBV controls, median HBV-DNA, ALT, LSM was 69 IU/mL, 33 U/L,5 kPa, respectively. PBMC stimulation with HBV core antigen (HBcAg) and HDV antigen (HDAg) showed weaker CD3 + CD4 + T-cell proliferation in HDV-RNA+ vs. HDV RNA- and HBV-mono-infected patients (p < 0.05). In HDV-RNA+ patients, a correlation between ALT and TNF-α (r = 0.76, p = 0.008), higher IL-10 levels and increased proportion of CD14 + TNF-α+ cells were found. Conclusion: In summary, during HBV/HDV coinfection, HDV RNA+ patients had weaker HBV and HDV specific responses, associated with increased TNF-α + monocytes irrespective of IFN treatment.

Experimental Drugs for the Treatment of Hepatitis D.

Chronic hepatitis D virus infection is the most severe form of viral hepatitis. Antiviral treatment is urgently needed to prevent patients from developing end stage liver disease or hepatocellular carcinoma. Treatment options were limited to off-label use of pegylated interferon alfa until conditional approval of bulevirtide by the EMA (European Medicines Agency) in July 2020. However, several other antiviral compounds are currently investigated and represent promising agents for the treatment of chronic HDV infection.

Early Multiphasic HBV Infection Initiation Kinetics Is Not Clone-Specific and Is Not Affected by Hepatitis D Virus (HDV) Infection.

Backgrounds and Aims: We previously demonstrated that serum hepatitis B virus (HBV) DNA in HBV infected humanized mice exhibited a highly dynamic multiphasic kinetic pattern from infection initiation to steady-state. Here, we investigated whether this pattern is consistent across different HBV clones or in the presence of hepatitis D virus (HDV) co-infection. Methods: We analyzed early serum viral kinetics using 26 HBV genotype C (GtC) mono-infected mice [clones: PXB, Hiroshima GtC CL4 (CL4) and Hiroshima GtC CL5 (CL5)] and four HBV CL4/HDV genotype one co-infected mice. Results: The HBV kinetics observed with clones CL4 and CL5 were similar to that previously defined in HBV PXB infected mice. Additionally, no significant differences in HBV DNA levels were observed between HBV mono-infected and HBV/HDV co-infected mice through 4 weeks post-inoculation (p.i.). However, HBV DNA levels at 6 weeks p.i. in HBV/HDV co-infected mice were significantly lower than those in HBV mono-infected mice (P = 0.002), consistent with HDV suppression of chronic HBV. Conclusions: HBV infection initiation is multiphasic across multiple viral clones and is not altered by HDV co-infection. The latter suggests that higher HDV titers (>8 log IU/mL) and/or longer duration of HDV infection might be needed to trigger HDV-induced suppression on HBV.