HBV001: Phase I study evaluating the safety and immunogenicity of the therapeutic vaccine ChAdOx1-HBV.

Background & Aims: Millions of people worldwide are infected chronically with HBV, which results in significant morbidity and mortality. Therapeutic vaccination is a strategy that aims to induce functional cure by restoring cellular immunity to HBV. Previously we have shown the candidate HBV immunotherapeutic vaccine ChAdOx1-HBV, encoding all major HBV antigens and a genetic adjuvant (shark invariant chain), is highly immunogenic in mice. Methods: Here we report the results of HBV001, a first-in-human, phase I, non-randomised, dose-escalation trial of ChAdOx1-HBV assessed in healthy volunteers and patients with chronic HBV (CHB). Results: Vaccination with a single dose of ChAdOx1-HBV was safe and well tolerated in both healthy and CHB cohorts. Vaccination induced high magnitude HBV-specific T cell responses against all major HBV antigens (core, polymerase, and surface) in healthy volunteers. Responses were detected but lower in patients with CHB. T cells generated by vaccination were cross-reactive between HBV C and D genotypes. Conclusions: ChAdOx1-HBV is safe and immunogenic in healthy volunteers and patients with CHB. In further studies, ChAdOx1-HBV will be used in combination with other therapeutic strategies with an aim to overcome the attenuated immunogenicity in patients with CHB. Impact and implications: Therapeutic vaccine ChAdOx1-HBV, a novel treatment for chronic hepatitis B infection (CHB), has been shown to be immunogenic in preclinical studies. In HBV001, a first-in-human phase I study, we show vaccination with ChAdOx1-HBV is safe and generates high magnitude T cell responses in healthy volunteers and lower levels of responses in patients with CHB. This is an important first step in the development of ChAdOx1-HBV as part of a wider therapeutic strategy to induce hepatitis B functional cure, and is of great interest to patients CHB and clinicians treating the condition. Clinical Trials Registration: This study is registered at ClinicalTrials.gov (NCT04297917).

NK cells limit therapeutic vaccine-induced CD8+T cell immunity in a PD-L1-dependent manner.

A better understanding of mechanisms that regulate CD8+T cell responses to therapeutic vaccines is needed to develop approaches to enhance vaccine efficacy for chronic viral infections and cancers. We show here that NK cell depletion enhanced antigen-specific T cell responses to chimp adenoviral vector (ChAdOx) vaccination in a mouse model of chronic HBV infection (CHB). Probing the mechanism underlying this negative regulation, we observed that CHB drove parallel up-regulation of programmed cell death ligand 1 (PD-L1) on liver-resident NK cells and programmed cell death 1 (PD-1) on intrahepatic T cells. PD-L1-expressing liver-resident NK cells suppressed PD-1hiCD8+T cells enriched within the HBV-specific response to therapeutic vaccination. Cytokine activation of NK cells also induced PD-L1, and combining cytokine activation with PD-L1 blockade resulted in conversion of NK cells into efficient helpers that boosted HBV-specific CD8+T cell responses to therapeutic vaccination in mice and to chronic infection in humans. Our findings delineate an immunotherapeutic combination that can boost the response to therapeutic vaccination in CHB and highlight the broader importance of PD-L1-dependent regulation of T cells by cytokine-activated NK cells.

The Role of B Cells and B Cell Therapies in Immune-Mediated Liver Diseases.

B cells form a branch of the adaptive immune system, essential for the body's immune defense against pathogens. B cell dysfunction has been implicated in the pathogenesis of immune mediated liver diseases including autoimmune hepatitis, IgG4-related hepatobiliary disease, primary biliary cholangitis and primary sclerosing cholangitis. B cells may initiate and maintain immune related liver diseases in several ways including the production of autoantibodies and the activation of T cells via antigen presentation or cytokine production. Here we comprehensively review current knowledge on B cell mechanisms in immune mediated liver diseases, exploring disease pathogenesis, B cell therapies, and novel treatment targets. We identify key areas where future research should focus to enable the development of targeted B cell therapies.

Therapeutic vaccination for treatment of chronic hepatitis B.

Chronic hepatitis B infection remains a serious global health threat, contributing to a large number of deaths through liver cirrhosis and hepatocellular carcinoma. Current treatment does not eradicate disease, and therefore new treatments are urgently needed. In acute hepatitis B virus (HBV) a strong immune response is necessary to clear the virus, but in chronic infection the immune response is weakened and dysfunctional. Therapeutic vaccination describes the process of inoculating individuals with a non-infective form of viral antigen with the aim of inducing or boosting existing HBV-specific immune responses, resulting in sustained control of HBV infection. In this review we outline the rationale for therapeutic vaccination in chronic HBV infection, discuss previous and ongoing trials of novel HBV therapeutic vaccine candidates and outline strategies to improve vaccine efficacy going forward.

Outcomes following SARS-CoV-2 infection in patients with chronic liver disease: An international registry study.

BACKGROUND & AIMS: Chronic liver disease (CLD) and cirrhosis are associated with immune dysregulation, leading to concerns that affected patients may be at risk of adverse outcomes following SARS-CoV-2 infection. We aimed to determine the impact of COVID-19 on patients with pre-existing liver disease, which currently remains ill-defined. METHODS: Between 25th March and 8th July 2020, data on 745 patients with CLD and SARS-CoV-2 (including 386 with and 359 without cirrhosis) were collected by 2 international registries and compared to data on non-CLD patients with SARS-CoV-2 from a UK hospital network. RESULTS: Mortality was 32% in patients with cirrhosis compared to 8% in those without (p <0.001). Mortality in patients with cirrhosis increased according to Child-Pugh class (A [19%], B [35%], C [51%]) and the main cause of death was from respiratory failure (71%). After adjusting for baseline characteristics, factors associated with death in the total CLD cohort were age (odds ratio [OR] 1.02; 1.01-1.04), Child-Pugh A (OR 1.90; 1.03-3.52), B (OR 4.14; 2.4-7.65), or C (OR 9.32; 4.80-18.08) cirrhosis and alcohol-related liver disease (OR 1.79; 1.03-3.13). Compared to patients without CLD (n = 620), propensity-score-matched analysis revealed significant increases in mortality in those with Child-Pugh B (+20.0% [8.8%-31.3%]) and C (+38.1% [27.1%-49.2%]) cirrhosis. Acute hepatic decompensation occurred in 46% of patients with cirrhosis, of whom 21% had no respiratory symptoms. Half of those with hepatic decompensation had acute-on-chronic liver failure. CONCLUSIONS: In the largest such cohort to date, we demonstrate that baseline liver disease stage and alcohol-related liver disease are independent risk factors for death from COVID-19. These data have important implications for the risk stratification of patients with CLD across the globe during the COVID-19 pandemic. LAY SUMMARY: This international registry study demonstrates that patients with cirrhosis are at increased risk of death from COVID-19. Mortality from COVID-19 was particularly high among patients with more advanced cirrhosis and those with alcohol-related liver disease.

Outcomes following SARS-CoV-2 infection in liver transplant recipients: an international registry study.

BACKGROUND: Despite concerns that patients with liver transplants might be at increased risk of adverse outcomes from COVID-19 because of coexisting comorbidities and use of immunosuppressants, the effect of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on this patient group remains unclear. We aimed to assess the clinical outcomes in these patients. METHODS: In this multicentre cohort study, we collected data on patients with laboratory-confirmed SARS-CoV-2 infection, who were older than 18 years, who had previously received a liver transplant, and for whom data had been submitted by clinicians to one of two international registries (COVID-Hep and SECURE-Cirrhosis) at the end of the patient's disease course. Patients without a known hospitalisation status or mortality outcome were excluded. For comparison, data from a contemporaneous cohort of consecutive patients with SARS-CoV-2 infection who had not received a liver transplant were collected from the electronic patient records of the Oxford University Hospitals National Health Service Foundation Trust. We compared the cohorts with regard to several outcomes (including death, hospitalisation, intensive care unit [ICU] admission, requirement for intensive care, and need for invasive ventilation). A propensity score-matched analysis was done to test for an association between liver transplant and death. FINDINGS: Between March 25 and June 26, 2020, data were collected for 151 adult liver transplant recipients from 18 countries (median age 60 years [IQR 47-66], 102 [68%] men, 49 [32%] women) and 627 patients who had not undergone liver transplantation (median age 73 years [44-84], 329 [52%] men, 298 [48%] women). The groups did not differ with regard to the proportion of patients hospitalised (124 [82%] patients in the liver transplant cohort vs 474 [76%] in the comparison cohort, p=0·106), or who required intensive care (47 [31%] vs 185 [30%], p=0·837). However, ICU admission (43 [28%] vs 52 [8%], p<0·0001) and invasive ventilation (30 [20%] vs 32 [5%], p<0·0001) were more frequent in the liver transplant cohort. 28 (19%) patients in the liver transplant cohort died, compared with 167 (27%) in the comparison cohort (p=0·046). In the propensity score-matched analysis (adjusting for age, sex, creatinine concentration, obesity, hypertension, diabetes, and ethnicity), liver transplantation did not significantly increase the risk of death in patients with SARS-CoV-2 infection (absolute risk difference 1·4% [95% CI -7·7 to 10·4]). Multivariable logistic regression analysis showed that age (odds ratio 1·06 [95% CI 1·01 to 1·11] per 1 year increase), serum creatinine concentration (1·57 [1·05 to 2·36] per 1 mg/dL increase), and non-liver cancer (18·30 [1·96 to 170·75]) were associated with death among liver transplant recipients. INTERPRETATION: Liver transplantation was not independently associated with death, whereas increased age and presence of comorbidities were. Factors other than transplantation should be preferentially considered in relation to physical distancing and provision of medical care for patients with liver transplants during the COVID-19 pandemic. FUNDING: European Association for the Study of the Liver, US National Institutes of Health, UK National Institute for Health Research.

The Application of Single-Cell RNA Sequencing in Vaccinology.

Single-cell RNA sequencing allows highly detailed profiling of cellular immune responses from limited-volume samples, advancing prospects of a new era of systems immunology. The power of single-cell RNA sequencing offers various opportunities to decipher the immune response to infectious diseases and vaccines. Here, we describe the potential uses of single-cell RNA sequencing methods in prophylactic vaccine development, concentrating on infectious diseases including COVID-19. Using examples from several diseases, we review how single-cell RNA sequencing has been used to evaluate the immunological response to different vaccine platforms and regimens. By highlighting published and unpublished single-cell RNA sequencing studies relevant to vaccinology, we discuss some general considerations how the field could be enriched with the widespread adoption of this technology.

Experience from the first UK inter-regional specialist multidisciplinary meeting in the diagnosis and management of IgG4-related disease.

Immunoglobulin G4-related disease (IgG4-RD) is a complex multisystem fibro-inflammatory disorder, requiring diagnostic differentiation from malignancy and other immune-mediated conditions, and careful management to minimise glucocorticoid-induced toxicity and prevent progressive organ dysfunction. We describe the experience of the first inter-regional specialist IgG4-RD multidisciplinary team meeting (MDM) incorporating a broad range of generalists and specialists, held 6-weekly via web-link between Oxford University Hospitals NHS Foundation Trust and University College London Hospitals NHS Foundation Trust. Over 3 years, there were 206 discussions on 156 patients. Of these, 97 (62%) were considered to have definite or possible IgG4-RD; 67% had multi-organ involvement and 23% had a normal serum IgG4. The average number of specialist opinions sought prior to MDM was four per patient. Management was changed in the majority of patients (74%) with the treatment escalation recommended in 61 cases, including 19 for rituximab. Challenges arose from delays and misdiagnosis, cross-specialty presentation and the management of sub-clinical disease. Our cross-discipline IgG4-RD MDM enabled important diagnostic and management decisions in this complex multisystem disorder, and can be used as a model for other centres in the UK.

The Design and Development of a Multi-HBV Antigen Encoded in Chimpanzee Adenoviral and Modified Vaccinia Ankara Viral Vectors; A Novel Therapeutic Vaccine Strategy against HBV.

Chronic hepatitis B virus (HBV) infection affects 257 million people globally. Current therapies suppress HBV but viral rebound occurs on cessation of therapy; novel therapeutic strategies are urgently required. To develop a therapeutic HBV vaccine that can induce high magnitude T cells to all major HBV antigens, we have developed a novel HBV vaccine using chimpanzee adenovirus (ChAd) and modified vaccinia Ankara (MVA) viral vectors encoding multiple HBV antigens. ChAd vaccine alone generated very high magnitude HBV specific T cell responses to all HBV major antigens. The inclusion of a shark Invariant (SIi) chain genetic adjuvant significantly enhanced the magnitude of T-cells against HBV antigens. Compared to ChAd alone vaccination, ChAd-prime followed by MVA-boost vaccination further enhanced the magnitude and breadth of the vaccine induced T cell response. Intra-cellular cytokine staining study showed that HBV specific CD8+ and CD4+ T cells were polyfunctional, producing combinations of IFNγ, TNF-α, and IL-2. In summary, we have generated genetically adjuvanted ChAd and MVA vectored HBV vaccines with the potential to induce high-magnitude T cell responses through a prime-boost therapeutic vaccination approach. These pre-clinical studies pave the way for new studies of HBV therapeutic vaccination in humans with chronic hepatitis B infection.

A systematic review of comorbidities and outcomes of adult patients with pleural infection.

BACKGROUND: Pleural infection remains an important cause of mortality. This study aimed to investigate worldwide patterns of pre-existing comorbidities and clinical outcomes of patients with pleural infection. METHODS: Studies reporting on adults with pleural infection between 2000 and 2017 were identified from a search of Embase and MEDLINE. Articles reporting exclusively on tuberculous, fungal or post-pneumonectomy infection were excluded. Two reviewers assessed 20 980 records for eligibility. RESULTS: 211 studies met the inclusion criteria. 134 articles (227 898 patients, mean age 52.8 years) reported comorbidity and/or outcome data. The majority of studies were retrospective observational cohorts (n=104, 78%) and the most common region of reporting was East Asia (n=33, 24%) followed by North America (n=27, 20%). 85 articles (50 756 patients) reported comorbidity. The median (interquartile range (IQR)) percentage prevalence of any comorbidity was 72% (58-83%), with respiratory illness (20%, 16-32%) and cardiac illness (19%, 15-27%) most commonly reported. 125 papers (192 298 patients) reported outcome data. The median (IQR) length of stay was 19 days (13-27 days) and median in-hospital or 30-day mortality was 4% (IQR 1-11%). In regions with high-income economies (n=100, 74%) patients were older (mean 56.5 versus 42.5 years, p<0.0001), but there were no significant differences in prevalence of pre-existing comorbidity nor in length of hospital stay or mortality. CONCLUSION: Patients with pleural infection have high levels of comorbidity and long hospital stays. Most reported data are from high-income economy settings. Data from lower-income regions is needed to better understand regional trends and enable optimal resource provision going forward.

The microbiology of pleural infection in adults: a systematic review.

BACKGROUND AND OBJECTIVES: Pleural infection is a major cause of morbidity and mortality among adults. Identification of the offending organism is key to appropriate antimicrobial therapy. It is not known whether the microbiological pattern of pleural infection is variable temporally or geographically. This systematic review aimed to investigate available literature to understand the worldwide pattern of microbiology and the factors that might affect such pattern. DATA SOURCES AND ELIGIBILITY CRITERIA: Ovid MEDLINE and Embase were searched between 2000 and 2018 for publications that reported on the microbiology of pleural infection in adults. Both observational and interventional studies were included. Studies were excluded if the main focus of the report was paediatric population, tuberculous empyema or post-operative empyema. STUDY APPRAISAL AND SYNTHESIS METHODS: Studies of ≥20 patients with clear reporting of microbial isolates were included. The numbers of isolates of each specific organism/group were collated from the included studies. Besides the overall presentation of data, subgroup analyses by geographical distribution, infection setting (community versus hospital) and time of the report were performed. RESULTS: From 20 980 reports returned by the initial search, 75 articles reporting on 10 241 patients were included in the data synthesis. The most common organism reported worldwide was Staphylococcus aureus. Geographically, pneumococci and viridans streptococci were the most commonly reported isolates from tropical and temperate regions, respectively. The microbiological pattern was considerably different between community- and hospital-acquired infections, where more Gram-negative and drug-resistant isolates were reported in the hospital-acquired infections. The main limitations of this systematic review were the heterogeneity in the method of reporting of certain bacteria and the predominance of reports from Europe and South East Asia. CONCLUSIONS: In pleural infection, the geographical location and the setting of infection have considerable bearing on the expected causative organisms. This should be reflected in the choice of empirical antimicrobial treatment.

Activated T-Follicular Helper 2 Cells Are Associated With Disease Activity in IgG4-Related Sclerosing Cholangitis and Pancreatitis.

OBJECTIVES: Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) and autoimmune pancreatitis (AIP) are characterized by an abundance of circulating and tissue IgG4-positive plasma cells. T-follicular helper (Tfh) cells are necessary for B-cell differentiation into plasma cells. We aimed at elucidating the presence and phenotype of Tfh cells and their relationship with disease activity in IgG4-SC/AIP. METHODS: Circulating Tfh-cell subsets were characterized by multiparametric flow cytometry in IgG4-SC/AIP (n = 18), disease controls with primary sclerosing cholangitis (n = 8), and healthy controls (HCs, n = 9). Tissue Tfh cells were characterized in IgG4-SC/AIP (n = 12) and disease control (n = 10) specimens. Activated PD1+ Tfh cells were cocultured with CD27+ memory B cells to assess their capacity to support B-cell differentiation. Disease activity was assessed using the IgG4-responder index and clinical parameters. RESULTS: Activated circulating PD-1+CXCR5+ Tfh cells were expanded in active vs inactive IgG4-SC/AIP, primary sclerosing cholangitis, and HC (P < 0.01), with enhanced PD-1 expression on all Tfh-cell subsets (Tfh1, P = 0.003; Tfh2, P = 0.0006; Th17, P = 0.003). Expansion of CD27+CD38+CD19lo plasmablasts in active disease vs HC (P = 0.01) correlated with the PD-1+ Tfh2 subset (r = 0.69, P = 0.03). Increased IL-4 and IL-21 cytokine production from stimulated cells of IgG4-SC/AIP, important in IgG4 class switch and proliferation, correlated with PD-1+ Tfh2 (r = 0.89, P = 0.02) and PD-1+ Tfh17 (r = 0.83, P = 0.03) subsets. Coculture of PD1+ Tfh with CD27+ B cells induced higher IgG4 expression than with PD1- Tfh (P = 0.008). PD-1+ Tfh2 cells were strongly associated with clinical markers of disease activity: sIgG4 (r = 0.70, P = 0.002), sIgE (r = 0.66, P = 0.006), and IgG4-responder index (r = 0.60, P = 0.006). Activated CXCR5+ Tfh cells homed to lymphoid follicles in IgG4-SC/AIP tissues. CONCLUSIONS: Circulating and tissue-activated Tfh cells are expanded in IgG4-SC/AIP, correlate with disease activity, and can drive class switch and proliferation of IgG4-committed B cells. PD1+ Tfh2 cells may be a biomarker of active disease and a potential target for immunotherapy.

Novel genetically-modified chimpanzee adenovirus and MVA-vectored respiratory syncytial virus vaccine safely boosts humoral and cellular immunity in healthy older adults.

OBJECTIVES: Respiratory syncytial virus (RSV) causes respiratory infection across the world, with infants and the elderly at particular risk of developing severe disease and death. The replication-defective chimpanzee adenovirus (PanAd3-RSV) and modified vaccinia virus Ankara (MVA-RSV) vaccines were shown to be safe and immunogenic in young healthy adults. Here we report an extension to this first-in-man vaccine trial to include healthy older adults aged 60-75 years. METHODS: We evaluated the safety and immunogenicity of a single dose of MVA-RSV given by intra-muscular (IM) injection (n = 6), two doses of IM PanAd3-RSV given 4-weeks apart (n = 6), IM PanAd3-RSV prime and IM MVA-RSV boost 8-weeks later (n = 6), intra-nasal (IN) spray of PanAd3-RSV prime and IM MVA-RSV boost 8-weeks later (n = 6), or no vaccine (n = 6). Safety measures included all adverse events within one week of vaccination and blood monitoring. Immunogenicity measures included serum antibody responses (RSV- and PanAd3-neutralising antibody titres measured by plaque-reduction neutralisation and SEAP assays, respectively), peripheral B-cell immune responses (frequencies of F-specific IgG and IgA antibody secreting cells and memory B-cells by ex vivo and cultured dual-colour ELISpot assays respectively), and peripheral RSV-specific T-cell immune responses (frequencies of IFNγ-producing T-cells by ex vivo ELISpot and CD4+/CD8+/Tfh-like cell frequencies by ICS/FACS assay). RESULTS: The vaccines were safe and well tolerated. Compared with each individual baseline immunity the mean fold-changes in serum RSV-neutralising antibody, appearance and magnitude of F-specific IgG and IgA ASCs and expansion of CD4+/CD8+ IFNγ-producing T-cells in peripheral circulation were comparable to the results seen from younger healthy adults who received the same vaccine combination and dose. There were little/no IgA memory B-cell responses in younger and older adults. Expansion of IFNγ-producing T-cells was most marked in older adults following IM prime, with balanced CD4+ and CD8+ T cell responses. The RSV-specific immune responses to vaccination did not appear to be attenuated in the presence of PanAd3 (vector) neutralising antibody. CONCLUSIONS: PanAd3-RSV and MVA-RSV was safe and immunogenic in older adults and the parallel induction of RSV-specific humoral and cellular immunity merits further assessment in providing protection from severe disease.

PYY plays a key role in the resolution of diabetes following bariatric surgery in humans.

BACKGROUND: Bariatric surgery leads to early and long-lasting remission of type 2 diabetes (T2D). However, the mechanisms behind this phenomenon remain unclear. Among several factors, gut hormones are thought to be crucial mediators of this effect. Unlike GLP-1, the role of the hormone peptide tyrosine tyrosine (PYY) in bariatric surgery in humans has been limited to appetite regulation and its impact on pancreatic islet secretory function and glucose metabolism remains under-studied. METHODS: Changes in PYY concentrations were examined in obese patients after bariatric surgery and compared to healthy controls. Human pancreatic islet function was tested upon treatment with sera from patients before and after the surgery, in presence or absence of PYY. Alterations in intra-islet PYY release and insulin secretion were analysed after stimulation with short chain fatty acids (SCFAs), bile acids and the cytokine IL-22. FINDINGS: We demonstrate that PYY is a key effector of the early recovery of impaired glucose-mediated insulin and glucagon secretion in bariatric surgery. We establish that the short chain fatty acid propionate and bile acids, which are elevated after surgery, can trigger PYY release not only from enteroendocrine cells but also from human pancreatic islets. In addition, we identify IL-22 as a new factor which is modulated by bariatric surgery in humans and which directly regulates PYY expression and release. INTERPRETATION: This study shows that some major metabolic benefits of bariatric surgery can be emulated ex vivo. Our findings are expected to have a direct impact on the development of new non-surgical therapy for T2D correction.