Background Chronic hepatitis B virus (HBV) infection disproportionately affects people living with HIV, who are often excluded from functional cure studies.Objective This study investigates CD8+ T cell profiles in HBV mono-infection versus HBV/HIV co-infection, examining the impact of long-term therapy on virus-specific responses to inform therapeutic strategies for immune restoration.Design We analysed CD8+ T cell responses in 61 participants (HBV n=20, HBV/HIV n=20, HIV n=21), on suppressive antiviral therapy, assessing transcriptomic and proteomic profiles, focusing on exhaustion markers alongside virus-specific functional capabilities.Results Transcriptomic analysis revealed distinct signatures in co-infection, with upregulation of TCR signalling genes, inhibitory pathways and progenitor-exhausted markers (XCL2, TCF7, PDCD1, IL7R). This profile scored highly for a precursor exhausted (Tpex) CD8+ T cell signature, reflecting stemness that maintains plasticity despite chronic antigen exposure. Proteomic analysis confirmed higher frequencies of Tpex (TCF-1+CD127+PD-1+) CD8+ T cells in co-infection, while HBV mono-infection showed predominance of terminally exhausted ToxhighTCF-1-CD127- cells. Tpex enrichment extended to HBV-specific populations corresponding with more robust, polyfunctional HBV-specific responses in co-infection against surface and core antigens. HBV-specific CD8 T cells maintained enhanced proliferative capacity and checkpoint responsiveness to anti-PDL1 blockade compared with HBV mono-infection. While co-infection was characterised by lower HBsAg levels and longer treatment duration, these factors alone did not account for the distinct immunological profiles.Conclusions People with well-controlled HBV/HIV co-infection maintain robust CD8+ T cell responses with preserved stem-like properties supporting antiviral function. These results challenge assumptions about additive immune dysfunction in dual chronic infections and highlight the need for tailored immune-modulatory therapies.

Hepatitis B virus (HBV) and hepatitis C virus (HCV) remain public health threats in the WHO European region, where an estimated 29 million people live with chronic infection and viral hepatitis-related deaths now surpass those from HIV/AIDS and tuberculosis combined. Although effective prevention tools and antiviral treatments reduce the risk of complications, overall mortality has not declined. This Series paper reviews models of care (MoC) implemented between 2015 and 2025, drawing on scientific literature and policy documents to assess regional progress. Simplified testing and treatment, childhood and targeted adult HBV vaccination, harm-reduction programmes, and prison-based interventions have advanced elimination efforts. Pragmatic approaches, including point-of-care testing, decentralised services, and integrated models tailored to key populations demonstrate clear benefits. However, major challenges persist: large undiagnosed populations, regional disparities, inadequate healthcare worker knowledge, and inequities affect at-risk groups. Achieving elimination by 2030 will require accelerated case-finding, broader access to simplified treatment, stronger risk-tailored and vaccination strategies, improved data systems, and renewed commitment.

Background & Aims:People with HBV/HIV co-infection on antiretroviral therapy achieve higher rates of HBV functional cure than those with HBV mono-infection, yet the immunological basis remains poorly characterised. HBV-specific CD4 + T cell responses are critical for viral control and functional cure but have been scarcely examined in HBV/HIV co-infection. Our previous studies in HBV/HIV co-infection demonstrated preserved stem-like CD8 + T cells and NK cell functional responses, but whether CD4 + T cell helper function is similarly maintained is unknown. Methods:We analysed CD4 + T cell responses in 72 participants (HBV n=26, HBV/HIV n=24, HIV n=22) on suppressive antiviral therapy, using multiparameter flow cytometry, virus-specific CD4 + T cell functional assays and proliferation assays. Results:People with HBV/HIV co-infection had significantly higher HBV envelope- and core-specific CD4 + T cell responses, with IL-2 production particularly discriminating between groups. CD4 + T cell responses to CEF (CMV, EBV, and Influenza) were comparable, confirming antigen specificity. Granzyme B-expressing cytotoxic CD4 + T cells and TCF-1 + CD127 + PD-1 + CD4 + T cells were enriched in co-infection. CD4 + and CD8 + T cell responses were more frequently coordinated within donors in co-infection than in mono-infection (envelope 83% vs 50%; core 94% vs 60%), where they were more often uncoupled. IL-2 producing CD4 + T cells correlated with CD8 + T cell responses and the CD4:CD8 ratio in co-infection. HBV-specific proliferative capacity was enhanced in co-infection. Conclusions:People with HBV/HIV co-infection mount functional HBV-specific CD4 + T helper responses that are coordinated with CD8 + T cell immunity at the individual level. Together with our prior findings of preserved NK and CD8 + T cell responses in this cohort, these data identify treated HBV/HIV co-infection as a setting of integrated, rather than compromised, antiviral immunity. Impact and Implications:People with HBV/HIV co-infection can achieve HBV functional cure more frequently than people with HBV mono-infection, but the immune mechanisms remain unclear. This study shows that treated HBV/HIV co-infection is characterised by functional HBV-specific CD4⁺ helper responses and coordinated CD4⁺/CD8⁺ antiviral immunity. These responses were most strongly associated with the CD4:CD8 ratio, a routinely available clinical marker, rather than with CD4 count alone. These findings argue that people with HBV/HIV co-infection should be prioritised in, not excluded from, HBV cure immunotherapy trials.

Background & Aims: Virus-specific T cells are crucial for controlling viral replication and disease progression in chronic hepatitis B (CHB). Nevertheless, due to the complexity of their analysis, CHB management relies exclusively on virological and biochemical markers. We aimed to develop a point-of-care immunological test, the HBV-cytokine release assay (HBV-CRA), designed to measure multiple cytokines in whole blood after HBV-peptide pool stimulation. Methods: We first assessed the assay′s sensitivity by spiking whole blood with engineered HBV-specific T cells. Next, the performance of HBV-CRA was compared to ex vivo IFN-γ ELISpot assays in terms of sensitivity and consistency. We then applied the assay in a cross-sectional study of 235 CHB patients and longitudinally in acute HBV patients during HBsAg sero-clearance. Results: The HBV-CRA detected cytokine secretion in response to peptide pools in approximately 80% of CHB patients. A profile of high IL-2 and IFN-γ after Core peptide stimulation was significantly associated with HBsAg clearance in acute HBV. The assay also revealed variability in cytokine levels and responses to different HBV proteins, even within the same clinical phase of CHB. Unsupervised clustering identified distinct HBV-specific immune patterns that did not segregate by clinical and virological categories. Notably, the assay revealed that NUC treatment impacted the functional profile of HBV-specific T cell responses. Conclusions: The HBV-CRA is a rapid, easy-to-use assay that detects immune profiles linked to HBsAg clearance and distinguishes CHB patients based on antiviral T cell function. This capability to stratify patients within similar clinical phases offers a novel biomarker for host-viral interactions and could guide the selection of novel immunotherapies. ### Competing Interest Statement NLB, ATT, and AB are the founders and hold stocks of T Cell Diagnostics (TCD), a biotech company that is developing T cell tests. SKH is an employee of TCD. None of the other authors have any relevant conflict of interest.

Chronic hepatitis B (CHB) is a leading cause of cirrhosis and hepatocellular carcinoma (HCC), with many patients remaining undiagnosed or undertreated despite effective vaccination and antiviral therapy. The 2025 European Association for the Study of the Liver (EASL) guidelines mark a shift towards biomarker-led, finite and personalised therapy, aiming for functional cure as sustained HBsAg loss. This review outlines updated recommendations on diagnosis, staging, treatment initiation and cessation, along with surveillance. Accurate interpretation of hepatitis B serological and virological markers remains central, with novel biomarkers, including quantitative HBsAg, HBcrAg and HBV RNA, enhancing disease stratification, guiding therapy and informing safe discontinuation of nucleos(t)ide analogues (NAs). The guidelines also emphasise the role of metabolic comorbidities, such as metabolic dysfunction-associated steatotic liver disease (MASLD), in accelerating fibrosis and increasing HCC risk. We summarise first-line NA and pegylated interferon options, monitoring requirements and surveillance strategies, highlighting common pitfalls such as under-recognition of at-risk patients with low viral load. Special considerations for pregnancy, immunosuppression and co-infections are addressed. Emerging therapies including RNA interference, core protein modulators and immunotherapeutics offer hope for finite, curative regimens. This article provides a practical, evidence-based guide for clinicians, trainees and allied health professionals to apply evolving recommendations in everyday practice.

Chronic hepatitis B (CHB) remains a major cause of cirrhosis and hepatocellular carcinoma (HCC) worldwide, affecting over 250 million people. In the UK, the burden is concentrated in migrant populations, yet diagnosis and treatment rates remain low. The 2025 European Association for the Study of the Liver guidelines mark a paradigm shift towards biomarker-led, personalised care, incorporating metabolic risk factors and focusing on functional cure, defined as sustained hepatitis B surface antigen (HBsAg) loss and undetectable hepatitis B virus (HBV) DNA. This review summarises key updates in diagnosis, staging, treatment initiation and cessation. The revised framework emphasises early treatment to prevent fibrosis progression and HCC, particularly in patients with metabolic dysfunction-associated steatotic liver disease, where disease progression can occur despite low viral load or normal alanine aminotransferase. Novel biomarkers, including quantitative HBsAg, hepatitis B core-related antigen and HBV RNA, are increasingly used to refine risk stratification, guide safe treatment discontinuation and identify patients for emerging therapies. Special populations, including pregnant individuals, those undergoing immunosuppression and patients with hepatitis D virus co-infection, require tailored management. Advances in minimally invasive liver fine needle aspiration allow detailed intrahepatic immune and virological profiling, supporting the development of new immunomodulatory and antiviral agents. By combining earlier diagnosis, integrated metabolic assessment, biomarker-led monitoring and novel therapies, the 2025 guidelines provide a blueprint for precision medicine in CHB, with the potential to improve outcomes and reduce the global burden of HBV-related liver disease.

BACKGROUND & AIMS:There is an unmet need for immunological biomarkers in chronic HBV infection (CHB), where patient management relies on virological and biochemical markers despite the crucial role of virus-specific T cells in controlling viral replication and disease progression. Here, we developed the HBV-cytokine release assay (HBV-CRA), a rapid, point-of-care test, to define whether HBV-specific T cell functional patterns are linked with conventional disease phase classifications. METHODS:Peptides covering pan-genotype HBV proteomes were utilized to trigger cytokine release by HBV-specific T cells in whole blood. We first assessed the assay's sensitivity by spiking whole blood with engineered HBV-specific T cells. Next, we compared the sensitivity and reproducibility of the HBV-CRA to ex vivo IFN-γ ELISpot assays. We then applied the assay in a cross-sectional study of 235 patients with CHB and longitudinally in patients with acute HBV infection (AHB) during HBsAg seroclearance. RESULTS:The HBV-CRA detected T cell function in 80% of CHB cases and showed that elevated IL-2 and IFN-γ levels after Core peptide stimulation were associated with HBsAg clearance in AHB. Unsupervised clustering identified distinct immune response patterns independent of established clinical and virological classifications and detected a functional impact of NUC treatment on HBV-specific T cell responses. CONCLUSIONS:The HBV-CRA is an easy-to-use assay that identifies immune profiles associated with HBsAg clearance in AHB and differentiates patients with CHB based on antiviral T cell function. Importantly, distinct HBV-specific T cell cytokine patterns were detected independently of conventional clinical disease phases, suggesting that stratification of patients with CHB for immunotherapeutic interventions should be guided by the HBV-CRA. IMPACT AND IMPLICATIONS:Challenges in collecting anti-HBV immune biomarkers from patients with chronic HBV infection (CHB) have led us to develop an easy-to-use assay (HBV-CRA) designed to quantify virus-specific T cell function in patient whole blood. We show that the HBV-CRA can identify immune profiles associated with HBsAg clearance in AHB and reveal functional T cell heterogeneity among patients with CHB that is not captured by standard clinical classifications. By offering a scalable, point-of-care immune monitoring tool, the HBV-CRA could support the development and implementation of personalized immunotherapeutic strategies in CHB management.

Background:Hepatitis B virus (HBV) infection remains a significant global health challenge, leading to chronic liver disease and hepatocellular carcinoma (HCC). Natural killer (NK) cells play an important role in the clearance of HBV-infected cells, but their efficacy is often compromised during chronic infection. Adaptive NK cells, characterised by NKG2C expression and enhanced functional responses, represent a promising therapeutic avenue for enhancing anti-HBV immunity and responses to HBV-driven cancers. Methods:We applied an established protocol, involving K562-HLA-E expressing feeder cells and cytokines (IL-2), for the expansion of adaptive NK cells from cryopreserved T- and B cell depleted peripheral blood mononuclear cells (PBMCs) derived from donors with chronic HBV infection alone or with Human Immunodeficiency Virus (HIV) co-infection. We evaluated the adaptive profile of expanded NK cells, their antibody-dependent cellular cytotoxicity (ADCC) capacity and functional responses against hepatoma cell lines in the presence or absence of HBV infection. Results:Expanded NK cells achieved >97% purity, with the NKG2C positive population exhibiting a mean 100-fold expansion. These cells demonstrated a predominantly adaptive phenotype with high surface expression of NKG2C and cytotoxic potential (Granzyme B). They maintained high levels of CD16 surface expression and upregulated CD2, essential for ADCC. Functionally, expanded adaptive NK cells showed enhanced ADCC capacity and functional responses to K562 targets, naive, HBV integrant-expressing, and de novo infected hepatoma cell lines. TGF-β preconditioning induced tissue-resident features (CD103, CD49a) in expanded adaptive NK cells, while preserving their adaptive phenotype and functionality, enhancing their potential for liver targeted immunotherapy. Further, expanded adaptive NK cells demonstrated minimal reactivity against autologous activated T cells, suggesting limited off-target effects. Conclusions:Our study demonstrates the first successful expansion of adaptive NK cells with robust functional responses from donors with chronic viral infection. This approach creates opportunities for NK cell-based therapies alone or in combination with monoclonal antibodies contributing to HBV functional cure strategies and the treatment of HBV-driven cancers.

BACKGROUND:Cholestatic liver disease disproportionately affects South Asians, yet they remain underrepresented in genomic studies. This recall study aimed to recall volunteers from a British South Asian genetic cohort that were considered to be at high risk of cholestatic liver disease based on their genotype or phenotype. METHODS:Cases were defined as participants with rare (minor allele frequency <1%) heterozygous loss of function (LoF) variants in ABCB4 and ABCB11 (genotype re-call) or with a previous intrahepatic cholestasis of pregnancy (ICP) diagnosis (ICD10 O26.6). Cases were matched 1:1 to controls. A detailed medical and family history was taken along with fasting anthropometric and transient elastography (TE) measurements and blood samples. RESULTS:Out of 22 eligible volunteers, 9 (41%) participate in the recall (8/9 genotype and 1/9 phenotype recall). Among the recalled cases there are 5 ABCB4 LoF, 3 ABCB11 LoF, and 1 ICP phenotype. Of these, 5/9 (55.6%) exhibit findings suggestive of liver involvement (genotype re-call). Specifically, 2/5 (50%) have increased liver stiffness on TE with one also demonstrating abnormal liver blood tests. 2/5(40%) report at least 2 cholestatic symptoms and an additional 1/5 (20%) demonstrates abnormal liver blood tests without increased liver stiffness. CONCLUSIONS:This study shows findings suggestive of liver involvement in 55.6% of volunteers, underscoring the potential of rare heterozygous ABCB4/11 variants as markers for identifying individuals at high risk of developing cholestatic liver disease. Consequently, individuals at higher genetic risk benefit from monitoring, personalised treatment and prevention strategies for cholestatic liver disease.

Chronic HBV infection disproportionately affects people living with HIV, who are often excluded from functional cure studies. This study investigates CD8 + T cell profiles in HBV mono-infection versus HBV/HIV co-infection, examining the impact of long-term therapy on virus-specific responses with the goal of informing therapeutic strategies for immune restoration. We analysed CD8 + T cell responses in 61 participants (HBV n=20, HBV/HIV n=20, HIV n=21), on suppressive antiviral therapy. We assessed transcriptomic and proteomic profiles, focusing on exhaustion markers alongside virus-specific functional capabilities. Transcriptomic analysis revealed a distinct signature in co-infection, with upregulation of genes associated with TCR signaling, inhibitory pathways and progenitor-exhausted markers ( XCL2, TCF7, PDCD1, IL7R ). This gene profile scored highly for a precursor exhausted (Tpex) CD8+ T cell signature, reflecting a "stemness" programme that maintains plasticity despite chronic antigen exposure. Proteomic analysis confirmed higher frequencies of precursor exhausted TCF-1 + CD127 + PD-1 + CD8 + T cells in co-infection, while HBV mono-infection showed predominance of terminally exhausted Tox high TCF-1 - CD127 - cells. These differences correlated with more robust, polyfunctional HBV-specific responses in co-infection against surface and core antigens. Lower HBsAg levels and longer treatment duration in co-infection associated positively with Tpex populations and functional responses and inversely with terminal exhaustion. Our findings demonstrate that individuals with well-controlled HBV/HIV co-infection maintain more robust CD8 + T cell responses with preserved stem-like properties supporting ongoing antiviral function. These results underscore the benefits of early antiretroviral intervention and the need for tailored immune-modulatory therapies to restore antiviral functionality in these diverse patient populations. Chronic hepatitis B virus (HBV) infection is marked by a progressive dysfunction of CD8⁺ T cells, which are crucial for antiviral responses. Traditionally these responses were thought to be more severely impacted in people with HBV/HIV co-infection. Our study provides new insights into the heterogeneous functional profiles of HBV-specific CD8⁺ T cells in people with HBV and HBV/HIV co-infection in the current antiretroviral therapy (ART) era. People living with HBV/HIV co-infection suppressed on antivirals have a higher prevalence of precursor exhausted CD8⁺ T cells (Tpex), alongside more effective antiviral responses when compared to those with HBV mono-infection. Our data demonstrate intrinsic differences in T cell profiles, revealing a paradoxical increase in terminally exhausted CD8⁺ T cells in people with HBV mono-infection. By providing a clearer understanding of CD8⁺ T cell dynamics in HBV mono-infection and HBV/HIV co-infection, our findings could inform the design of tailored immunotherapies aimed at revitalising antiviral responses. Furthermore, this research may influence practices regarding clinical management emphasising the need for early intervention strategies and individualised approaches tailored to T cell profiles rather than solely based on infection status.

[This corrects the article DOI: 10.1016/j.jhepr.2025.101382.].

Background & Aims:Type one (T1) and three interferons (T3IFNs) are implicated in chronic hepatitis B (CHB) immunopathogenesis. IFN remains the only licenced immune modulating therapy for CHB. We measured the prevalence of auto-antibodies (auto-Abs) against T1 and T3IFNs to examine the hypothesis that they impact HBV control and treatment response, as highlighted by COVID-19. Methods:Our multi-centre retrospective longitudinal study accessed two CHB cohorts; auto-Ab levels and neutralisation status were measured against T1IFN and T3IFN. Associations were tested against HBV clinical parameters. Results:Overall, 16.7% (46/276) of patients with CHB had any detectable anti-IFN auto-Abs at any time and 6.5% (18/276) anti-T3IFN auto-Abs, with a high incidence of PegIFNα-induced de novo auto-Abs (31.4%, 11/35). However, only a minority of auto-Ab-positive sera demonstrated neutralisation in vitro (4/46, 8.7%). Auto-Ab positivity correlated with higher median HBsAg levels (p = 0.0110). All individuals with detectable anti-T1IFN auto-Abs were PegIFNα non-responders. Conclusions:Non-neutralising anti-IFN auto-Abs are common in CHB and associate with higher median HBsAg levels. Further prospective study of anti-cytokine auto-Abs in CHB are required to characterise the association with long-term outcomes. Impact and implications:HBV and PegIFNα individually may induce broad autoreactivity associated with dysregulated antiviral immune responses. Auto-Ab screening prior to PegIFNα treatment or other immunotherapies may play a critical role in predicting treatment responses.

AbstractBackground & AimsThere is an unmet need for immunological biomarkers in chronic hepatitis B (CHB), where patient management relies on virological and biochemical markers despite the crucial role of virus-specific T cells in controlling viral replication and disease progression. To address this, we developed the HBV-cytokine release assay (HBV-CRA), a rapid, point-of-care test that measures multiple cytokines in whole blood after HBV-peptide stimulation.MethodsWe first assessed the assay’s sensitivity by spiking whole blood with engineered HBV-specific T cells. Next, we compared sensitivity and consistency of HBV-CRA to ex vivo IFN-γ ELISpot assays. We then applied the assay in a cross-sectional study of 235 CHB patients and longitudinally in acute HBV patients during HBsAg sero-clearance.ResultsThe HBV-CRA detected T cell function in 80% of CHB cases and showed that elevated IL-2 and IFN-γ levels after Core peptide stimulation were associated with HBsAg clearance. Importantly, unsupervised clustering identified distinct immune response patterns independent of established clinical and virological classifications. The assay also demonstrated the functional impact of NUC treatment on HBV-specific T cell responses.ConclusionsThe HBV-CRA is a rapid and easy-to-use assay that identifies immune profiles associated with HBsAg clearance and differentiates CHB patients based on antiviral T cell function. Its application in a large CHB cohort revealed that traditional disease phase classifications, based on viral and clinical parameters, cannot predict HBV-specific T cell profiles. The HBV-CRA has the potential to guide patient stratification for immunotherapeutic interventions.