When two viruses collide: coronavirus disease after hepatitis B virus reactivation.

The COVID-19 pandemic has exploded since the first cases were reported in Wuhan in December 2019, engulfing the globe. Many infected individuals are asymptomatic or have a mild or moderate disease. A subset of people with advanced age, the immunocompromised and those with chronic diseases, are prone to serious-to-critical illness. We report a fatal case of metastatic colorectal cancer survivor who developed COVID-19 after clinically reactivated hepatitis B virus (HBV) due to chemotherapy. The patient's COVID-19 illness was supposed to be related to her recent medical evaluation. Although being diagnosed with chronic HBV infection for decades, she was not treated with nucleotide analogue and the possibility to preclude HBV reactivation was missed. Moreover, infectious control practices must be draconian in order to save such a fragile population from infections.

Hepatitis D virus interferes with hepatitis B virus RNA production via interferon-dependent and -independent mechanisms.

BACKGROUND & AIMS: Chronic coinfection with HBV and HDV leads to the most aggressive form of chronic viral hepatitis. Herein, we aimed to elucidate the molecular mechanisms underlying the widely reported observation that HDV interferes with HBV in most coinfected patients. METHODS: Patient liver tissues, primary human hepatocytes, HepaRG cells and human liver chimeric mice were used to analyze the effect of HDV on HBV using virological and RNA-sequencing analyses, as well as RNA synthesis, stability and association assays. RESULTS: Transcriptomic analyses in cell culture and mouse models of coinfection enabled us to define an HDV-induced signature, mainly composed of interferon (IFN)-stimulated genes (ISGs). We also provide evidence that ISGs are upregulated in chronically HDV/HBV-coinfected patients but not in cells that only express HDV antigen (HDAg). Inhibition of the hepatocyte IFN response partially rescued the levels of HBV parameters. We observed less HBV RNA synthesis upon HDV infection or HDV protein expression. Additionally, HDV infection or expression of HDAg alone specifically accelerated the decay of HBV RNA, and HDAg was associated with HBV RNAs. On the contrary, HDAg expression did not affect other viruses such as HCV or SARS-CoV-2. CONCLUSIONS: Our data indicate that HDV interferes with HBV through both IFN-dependent and IFN-independent mechanisms. Specifically, we uncover a new viral interference mechanism in which proteins of a satellite virus affect the RNA production of its helper virus. Exploiting these findings could pave the way to the development of new therapeutic strategies against HBV. IMPACT AND IMPLICATIONS: Although the molecular mechanisms remained unexplored, it has long been known that despite its dependency, HDV decreases HBV viremia in patients. Herein, using in vitro and in vivo models, we showed that HDV interferes with HBV through both IFN-dependent and IFN-independent mechanisms affecting HBV RNA metabolism, and we defined the HDV-induced modulation signature. The mechanisms we uncovered could pave the way for the development of new therapeutic strategies against HBV by mimicking and/or increasing the effect of HDAg on HBV RNA. Additionally, the HDV-induced modulation signature could potentially be correlated with responsiveness to IFN-α treatment, thereby helping to guide management of HBV/HDV-coinfected patients.

Human antiviral B cell responses: Emerging lessons from hepatitis B and COVID-19.

Humoral immunity is a critical component of the coordinated response required to resolve viral infections and mediate protection following pathogen clearance or vaccination. A better understanding of factors shaping the memory B cell response will allow tailored development of efficient preventative vaccines against emerging acute viral infections, therapeutic vaccines, and immunotherapies for chronic viral infections. Here, we use recent data obtained by profiling antigen-specific B cell responses in hepatitis B as a framework to explore lessons that can be learnt from different viral infections about the diverse influences on humoral immunity. Hepatitis B provides a paradigm where successful B cell responses in resolved or vaccinated individuals can be contrasted to the failed response in chronic infection, while also exemplifying the degree to which B cell responses within infected individuals can differ to two antigens from the same virus. Drawing on studies in other human and murine infections, including emerging data from COVID-19, we consider the influence of antigen quantity and structure on the quality of the B cell response, the role of differential CD4 help, the importance of germinal center vs extrafollicular responses and the emerging concept that responses residing in non-lymphoid organs can participate in B cell memory.

Risk of Hepatitis B Virus Reactivation in Rheumatoid Arthritis Patients Undergoing Tocilizumab-Containing Treatment.

BACKGROUND AND AIM: To investigate the risk of hepatitis B virus reactivation in patients undergoing long-term tocilizumab therapy for rheumatoid arthritis. METHOD: From January 2011 through August 2019, a total of 97 patients were enrolled in this retrospective study. Clinical data, comedications, and the occurrence of HBV reactivation were recorded. RESULTS: Seven patients were HBsAg+ (7.2%), 64 were HBsAg-/HBcAb+ (65.9%), and 26 were HBsAg-/HBcAb- (26.8%). The median disease follow-up time was 9 years. TCZ was administered for a median of 29 months. Four patients (4.1%) experienced HBV reactivation after tocilizumab therapy. Of the 7 HBsAg+ patients, 4 received antiviral prophylaxis and had no HBV reactivation; the remaining 3 patients did not receive antiviral prophylaxis, and all 3 (100%) experienced HBV reactivation and hepatitis flare-up. Hyperbilirubinemia occurred in 2 of these 3 patients, with mild prothrombin time prolongation in one. After salvage entecavir treatment, all patients had a favorable outcome. Of the 64 HBsAg-/HBcAb+ patients, only one became positive for serum HBV DNA (2.5 × 107 IU/mL) after 18 months of tocilizumab treatment (1.6%; 1/64). This patient was immediately treated with entecavir, which prevented hepatitis flare-up. CONCLUSIONS: Tocilizumab is widely used in treating rheumatoid arthritis and has the potential to reduce the mortality rate among severe COVID-19 patients. However, HBV reactivation needs to be considered. HBsAg+ patients have a high risk of HBV reactivation, which could be prevented by antiviral prophylaxis. Although the risk of reactivation is low in HBsAg-/HBcAb+ patients, strict monitoring is necessary.

Low risk of hepatitis B reactivation in patients with severe COVID-19 who receive immunosuppressive therapy.

A significant proportion of patients infected with SARS-CoV-2 develop severe respiratory symptoms due to an excessive immune response. Treatment of this condition may include immunosuppressive therapies, such as IL-6 receptor antagonists and corticosteroids, which pose a risk for patients with active or past hepatitis B virus (HBV) infection. In this prospective cohort study, we analysed the risk of HBV reactivation in patients with severe COVID-19 and resolved HBV infection undergoing immunosuppressive therapy. From 15th March to 30th April 2020, 600 patients with severe COVID-19 were admitted to our hospital and treated with immune modulators. Data regarding HBV infection were available in 484, of whom 69 (14%) were HBsAg negative/anti-HBc positive. For these patients, HBV reactivation prophylaxis with entecavir was strongly recommended. Complete follow-up was available in 61 patients: 72% were male, median age was 67 years, and anti-HBs was >10 IU/mL in 72%. The immunosuppressive drug most used was tocilizumab (72%). Despite HBV prophylaxis recommendation, 38 (62%) patients received entecavir and 23 (38%) did not. Baseline features of both groups were similar. At follow-up, we found no cases of HBsAg seroreversion and only 2 (3%) patients (no prophylaxis group) had detectable serum HBV-DNA (<15 IU/mL). Both were anti-HBs negative and had normal aminotransferase levels. Our data show that the risk of HBV reactivation in patients with severe COVID-19 and resolved HBV infection undergoing immunosuppressive treatment is low. However, if a systematic follow-up after hospital discharge is unfeasible in patients without anti-HBs, a short course of antiviral prophylaxis may be a safe option.

Mesenchymal stem cells in the fight against viruses: Face to face with the invisible enemy.

The relative ease of isolation of mesenchymal stem cells (MSCs) from different tissues coupled with their culture expansion in vitro and their differentiation capacity to mesodermal, endodermal and ectodermal lineages have made these cells attractive for a large number of therapeutic applications. In recent years, there has been remarkable progress in the utilization of MSCs in diverse clinical indications both in animal models and human clinical trials. However, the potential of MSCs to control or treat viral diseases is still in its infancy. In this study, we report quantitative data on the MSC-based clinical trials over the last ten years as they appear on the online database of clinical research studies from US National Institutes of Health. In particular, we provide comprehensive review of either completed or ongoing clinical trials using MSCs for virus-associated diseases focusing on HIV, hepatitis B virus and COVID-19 virus.