IRF3-mediated pathogenicity in a murine model of human hepatitis A.

HAV-infected Ifnar1-/- mice recapitulate many of the cardinal features of hepatitis A in humans, including serum alanine aminotransferase (ALT) elevation, hepatocellular apoptosis, and liver inflammation. Previous studies implicate MAVS-IRF3 signaling in pathogenesis, but leave unresolved the role of IRF3-mediated transcription versus the non-transcriptional, pro-apoptotic activity of ubiquitylated IRF3. Here, we compare the intrahepatic transcriptomes of infected versus naïve Mavs-/- and Ifnar1-/- mice using high-throughput sequencing, and identify IRF3-mediated transcriptional responses associated with hepatocyte apoptosis and liver inflammation. Infection was transcriptionally silent in Mavs-/- mice, in which HAV replicates robustly within the liver without inducing inflammation or hepatocellular apoptosis. By contrast, infection resulted in the upregulation of hundreds of genes in Ifnar1-/- mice that develop acute hepatitis closely modeling human disease. Upregulated genes included pattern recognition receptors, interferons, chemokines, cytokines and other interferon-stimulated genes. Compared with Ifnar1-/- mice, HAV-induced inflammation was markedly attenuated and there were few apoptotic hepatocytes in livers of infected Irf3S1/S1Ifnar1-/- mice in which IRF3 is transcriptionally-inactive due to alanine substitutions at Ser-388 and Ser-390. Although transcriptome profiling revealed remarkably similar sets of genes induced in Irf3S1/S1Ifnar1-/- and Ifnar1-/- mice, a subset of genes was differentially expressed in relation to the severity of the liver injury. Prominent among these were both type 1 and type III interferons and interferon-responsive genes associated previously with apoptosis, including multiple members of the ISG12 and 2'-5' oligoadenylate synthetase families. Ifnl3 and Ifnl2 transcript abundance correlated strongly with disease severity, but mice with dual type 1 and type III interferon receptor deficiency remained fully susceptible to liver injury. Collectively, our data show that IRF3-mediated transcription is required for HAV-induced liver injury in mice and identify key IRF3-responsive genes associated with pathogenicity, providing a clear distinction from the transcription-independent role of IRF3 in liver injury following binge exposure to alcohol.

Hepatitis A virus-induced hsa-miR-146a-5p attenuates IFN-ß signaling by targeting adaptor protein TRAF6.

Hepatitis A virus (HAV), a unique hepatotropic human picornavirus, is the causative agent of acute hepatitis A in humans. Some studies have shown that HAV antagonizes the innate immune response by disrupting interferon-beta (IFN-ß) signaling by viral proteins. However, whether microRNAs (miRNAs), a class of non-coding RNAs, are involved in the antagonism of IFN-ß induction upon HAV infection is still unclear. In this study, we investigated the effects and mechanisms by which HAV-induced miRNAs antagonize IFN-ß signaling. A variety of analytical methods, including miRNA microarray, RT-qPCR, dual-luciferase reporter assay, and Western blotting, were performed using HAV-infected cells. The results indicated that HAV infection upregulates the expression of hsa-miR-146a-5p, which in turn partially suppresses the induction of IFN-ß synthesis, thereby promoting viral replication. Mechanistically, TRAF6 (TNF receptor-associated factor 6), a key adaptor protein in the RIG-I/MDA5-mediated IFN-I signaling pathway, is targeted and degraded by hsa-miR-146a-5p. As TRAF6 is necessary for IFN-ß induction, inhibition of this protein attenuates IFN-ß signaling. Taken together, the results from this study indicated that HAV disrupts RIG-I/MDA5-mediated IFN-I signaling partially through the cleavage of the essential adaptor molecule TRAF6 via hsa-miR-146a-5p.

Co-Occurrence of Hepatitis A Infection and Chronic Liver Disease.

Hepatitis A virus (HAV) infection occasionally leads to a critical condition in patients with or without chronic liver diseases. Acute-on-chronic liver disease includes acute-on-chronic liver failure (ACLF) and non-ACLF. In this review, we searched the literature concerning the association between HAV infection and chronic liver diseases in PubMed. Chronic liver diseases, such as metabolic associated fatty liver disease and alcoholic liver disease, coinfection with other viruses, and host genetic factors may be associated with severe hepatitis A. It is important to understand these conditions and mechanisms. There may be no etiological correlation between liver failure and HAV infection, but there is an association between the level of chronic liver damage and the severity of acute-on-chronic liver disease. While the application of an HAV vaccination is important for preventing HAV infection, the development of antivirals against HAV may be important for preventing the development of ACLF with HAV infection as an acute insult. The latter is all the more urgent given that the lives of patients with HAV infection and a chronic liver disease of another etiology may be at immediate risk.

Functions of human liver CD69+CD103-CD8+ T cells depend on HIF-2α activity in healthy and pathologic livers.

BACKGROUND & AIMS: Human liver CD69+CD8+ T cells are ~95% CD103- and ~5% CD103+. Although CD69+CD103+CD8+ T cells show tissue residency and robustly respond to antigens, CD69+CD103-CD8+ T cells are not yet well understood. METHODS: Liver perfusate and paired peripheral blood were collected from healthy living donors and recipients with cirrhosis during liver transplantation. Liver tissues were obtained from patients with acute hepatitis A. Phenotypic and functional analyses were performed by flow cytometry. Gene expression profiles were determined by microarray and quantitative reverse transcription PCR. PT-2385 was used to inhibit hypoxia-inducible factor (HIF)-2α. RESULTS: Human liver CD69+CD103-CD8+ T cells exhibited HIF-2α upregulation with a phenotype of tissue residency and terminal differentiation. CD103- cells comprised non-hepatotropic virus-specific T cells as well as hepatotropic virus-specific T cells, but CD103+ cells exhibited only hepatotropic virus specificity. Although CD103- cells were weaker effectors on a per cell basis than CD103+ cells, following T cell receptor or interleukin-15 stimulation, they remained the major CD69+CD8+ effector population in the liver, surviving with less cell death. An HIF-2α inhibitor suppressed the effector functions and survival of CD69+CD103-CD8+ T cells. In addition, HIF-2α expression in liver CD69+CD103-CD8+ T cells was significantly increased in patients with acute hepatitis A or cirrhosis. CONCLUSIONS: Liver CD69+CD103-CD8+ T cells are tissue resident and terminally differentiated, and their effector functions depend on HIF-2α. Furthermore, activation of liver CD69+CD103-CD8+ T cells with HIF-2α upregulation is observed during liver pathology. LAY SUMMARY: The immunologic characteristics and the role of CD69+CD103-CD8+ T cells, which are a major population of human liver CD8+ T cells, remain unknown. Our study shows that these T cells have a terminally differentiated tissue-resident phenotype, and their effector functions depend on a transcription factor, HIF-2α. Furthermore, these T cells were activated and expressed higher levels of HIF-2α in liver pathologies, suggesting that they play an important role in immune responses in liver tissues and the pathogenesis of human liver disease.

Cancer in Africa 2018: The role of infections.

We estimate the fractions of cancer attributed to infections in Africa in 2018. The number of new cancer cases occurring was taken from Globocan2018 with some additional estimations based on data from African population-based registries. Population attributable fractions were calculated using prevalence of infection and relative risk in exposed vs. nonexposed. The greatest share of infection-associated cancers is due to the human papillomaviruses (12.1% of all cancers in Africa and 15.4% in sub-Saharan Africa [SSA]); of these, cervical cancer is by far the most common. Kaposi sarcoma-associated herpesvirus is responsible for 3.1% of all cancers in Africa, the hepatitis viruses (B and C) for 2.9% and Helicobacter pylori for 2.7% (non-Cardia Gastric cancer and primary gastric lymphomas). Two percent of cancers are attributable to the Epstein-Barr virus, Schistosoma haematobium increases the risk of bladder cancer resulting in 1.0% of all cancers. HIV-related NHL and squamous cell carcinoma of the conjunctiva account for 0.6% of cancers. Altogether 24.5% of cancers in Africa and 28.7% in SSA are due to infectious agents. Infections are by far the most common cancer risk factor for cancer in Africa-the traditional risk factors (smoking, alcohol and unhealthy diet) probably cause only one in eight cancers in Africa. Prevention should focus on those infectious diseases preventable through vaccination (HPV and hepatitis B) which could reduce two-thirds of the burden. Helicobacter pylori and schistosomiasis are treatable with antibiotics and praziquantel, with a potential reduction of one in eight infection-associated cancers.

Involvement of the gallbladder in the course of viral hepatitis A in childhood.

The course of acute hepatitis A (AHA) in childhood is most often benign. There are relatively few reports of gallbladder involvement during such infection and its consequences. We discuss the cases of 75 children (mean age = 4.5 years) with confirmed AHA. Clinical and laboratory evaluation upon admission were classical for AHA. Only two children had normal bilirubin levels and 38.7% had visible involvement of the gallbladder with wall thickening of >3 mm, while six met criteria for acute acalculous cholecystitis. There appears to be no clear relationship between thickening of the gallbladder wall and transaminase levels, but a significant relationship with total and direct bilirubin levels (P < 0.05). Ultrasonographic examination should therefore be carried out in each case of AHA and follow-up should be performed with greater caution, if there are changes in the gallbladder wall.

Comparative Pathology of Hepatitis A Virus and Hepatitis E Virus Infection.

Hepatitis A virus (HAV) and hepatitis E virus (HEV) cause acute, self-limiting hepatic infections that are usually spread by the fecal-oral route in humans. Naturally occurring and experimental infections are possible in a variety of nonhuman primates and, in the case of HEV, a number of other species. Many advances in understanding the pathogenesis of these viruses have come from studies in experimental animals. In general, animals infected with these viruses recapitulate the histologic lesions seen in infected humans, but typically with less severe clinical and histopathological manifestations. This review describes the histopathologic changes associated with HAV and HEV infection in humans and experimental animals.

Novel duck hepatitis A virus type 1 isolates from adult ducks showing egg drop syndrome.

Generally, duck hepatitis A virus type 1 (DHAV-1) only infects young ducklings. Since December 2016, severe outbreaks of duck viral infection with egg drop, feed consumption decline, and ovary-oviduct disease have occurred in some laying duck flocks in Shandong Province of China. DHAV-1 isolated from the affected ducks was confirmed as the causative pathogen of the egg drop. Compared with other DHAV-1 strains, the novel isolate has three special amino acid mutation points in the most variable regions at the C-terminus of VP1. The experimental infection in laying ducks indicated that successful immunization with DHAV-1 vaccine could protect laying duck from infection. To the best of our knowledge, this is the first reported incidence of a severe duck disease outbreak involving egg drop syndrome caused by DHAV-1.

Prevalence of human anelloviruses in Romanian healthy subjects and patients with common pathologies.

BACKGROUND: Human anelloviruses (TTV, TTMDV and TTMV) are at high prevalence all across the globe, having also a controversial disease-inducing potential. This study aimed to estimate the prevalence of anelloviral DNA in the Romanian human population and to investigate the association of infections with common pathologies in Romanian population. METHODS: After informed consent, blood samples were collected from 2000 subjects represented by: clinically healthy individuals (n = 701) and a group of patients with pathologies linked to low grade inflammation or alteration of carbohydrate metabolism (n = 1299). All samples were analysed for the presence of TTV, TTMDV and TTMV DNA by hemi-nested PCR. RESULTS: The prevalence of TTV, TTMDV and TTMV in the studied population was 68.2, 54.4%, respectively 40.1%, lower than the recent reports from other geographic regions. The three viral species were significantly more frequent in the group of patients compared to the healthy subjects and were associated with type 2 diabetes mellitus. The presence of anelloviral DNA was also associated with medical procedures (e.g. haemodialysis/transfusions, surgical procedures) and previous hepatitis A virus infection. Lifestyle choices related to alcohol consumption, smoking, physical activity and living environment were not associated with differences in distribution of the three viruses. CONCLUSION: Further evidence is needed to establish a correlation between infection with human anelloviruses and a pathology or group of pathologies.

Natural History, Clinical Manifestations, and Pathogenesis of Hepatitis A.

Hepatitis A virus (HAV) is transmitted by the fecal-oral route and is a major cause of acute viral hepatitis. The clinical manifestations of HAV infection range from asymptomatic infection to acute liver failure (ALF), but do not include progression to chronic hepatitis. Risk factors for severe acute hepatitis A are older age (>40 years) and preexisting liver disease. Some patients may show atypical clinical features such as relapsing hepatitis, prolonged cholestasis, or extrahepatic manifestations. Almost all hepatitis A patients spontaneously recover with supportive care. However, in the case of ALF (<1%), intensive care and urgent decision on liver transplantation are required. Liver injury during hepatitis A is not directly caused by HAV but is known to be caused by immune-mediated mechanisms. In this review, the natural history and clinical manifestations of hepatitis A are described. In addition, mechanisms of immunopathogenesis in hepatitis A are discussed.

HAVCR1 (CD365) and Its Mouse Ortholog Are Functional Hepatitis A Virus (HAV) Cellular Receptors That Mediate HAV Infection.

The hepatitis A virus (HAV) cellular receptor 1 (HAVCR1), classified as CD365, was initially discovered as an HAV cellular receptor using an expression cloning strategy. Due to the lack of HAV receptor-negative replication-competent cells, it was not possible to fully prove that HAVCR1 was a functional HAV receptor. However, biochemistry, classical virology, and epidemiology studies further supported the functional role of HAVCR1 as an HAV receptor. Here, we show that an anti-HAVCR1 monoclonal antibody that protected African green monkey kidney (AGMK) cells against HAV infection only partially protected monkey Vero E6 cells and human hepatoma Huh7 cells, indicating that these two cell lines express alternative yet unidentified HAV receptors. Therefore, we focused our work on AGMK cells to further characterize the function of HAVCR1 as an HAV receptor. Advances in clustered regularly interspaced short palindromic repeat/Cas9 technology allowed us to knock out the monkey ortholog of HAVCR1 in AGMK cells. The resulting AGMK HAVCR1 knockout (KO) cells lost susceptibility to HAV infection, including HAV-free viral particles (vpHAV) and exosomes purified from HAV-infected cells (exo-HAV). Transfection of HAVCR1 cDNA into AGMK HAVCR1 KO cells restored susceptibility to vpHAV and exo-HAV infection. Furthermore, transfection of the mouse ortholog of HAVCR1, mHavcr1, also restored the susceptibility of AGMK HAVCR1 KO cells to HAV infection. Taken together, our data clearly show that HAVCR1 and mHavcr1 are functional HAV receptors that mediate HAV infection. This work paves the way for the identification of alternative HAV receptors to gain a complete understanding of their interplay with HAVCR1 in the cell entry and pathogenic processes of HAV.IMPORTANCE HAVCR1, an HAV receptor, is expressed in different cell types, including regulatory immune cells and antigen-presenting cells. How HAV evades the immune response during a long incubation period of up to 4 weeks and the mechanism by which the subsequent necroinflammatory process clears the infection remain a puzzle that most likely involves the HAV-HAVCR1 interaction. Based on negative data, a recent paper from the S. M. Lemon and W. Maury laboratories (A. Das, A. Hirai-Yuki, O. Gonzalez-Lopez, B. Rhein, S. Moller-Tank, R. Brouillette, L. Hensley, I. Misumi, W. Lovell, J. M. Cullen, J. K. Whitmire, W. Maury, and S. M. Lemon, mBio 8:e00969-17, 2017, https://doi.org/10.1128/mBio.00969-17) suggested that HAVCR1 is not a functional HAV receptor, nor it is it required for HAV infection. However, our data, based on regain of the HAV receptor function in HAVCR1 knockout cells transfected with HAVCR1 cDNA, disagree with their findings. Our positive data show conclusively that HAVCR1 is indeed a functional HAV receptor and lays the ground for the identification of alternative HAV receptors and how they interact with HAVCR1 in cell entry and the pathogenesis of HAV.

Experimental infection of Marmota monax with a novel hepatitis A virus.

To establish an animal model for the newly identified Marmota Himalayana hepatovirus, MHHAV, so as to develop a better understanding of the infection of hepatitis A viruses. Five experimental woodchucks (Marmota monax) were inoculated intravenously with the purified MHHAV from wild woodchuck feces. One animal injected with PBS was defined as a control. Feces and blood were routinely collected. After the animals were subjected to necropsy, different tissues were collected. The presence of viral RNA and negative sense viral RNA was analyzed in all the samples and histopathological and in situ hybridization analysis was performed for the tissues. MHHAV infection caused fever but no severe symptoms or death. Virus was shed in feces beginning at 2 dpi, and MHHAV RNA persisted in feces for ~2 months, with a biphasic increase, and in blood for ~30 days. Viral RNA was detected in all the tissues, with high levels in the liver and spleen. Negative-strand viral RNA was detected only in the liver. Furthermore, the animals showed histological signs of hepatitis at 45 dpi. MHHAV can infect M. monax and is associated with hepatic disease. Therefore, this animal can be used as a model of HAV pathogenesis and to evaluate antiviral and anticancer therapeutics.

Conjugated Bilirubin Upregulates TIM-3 Expression on CD4+CD25+ T Cells: Anti-Inflammatory Implications for Hepatitis A Virus Infection.

Bilirubin (BR), a metabolite with increased concentrations in plasma during viral hepatitis, has been recognized as a potential immune-modulator. We recently reported that conjugated BR (CB) augments regulatory T cell (Treg) suppressor activity during acute hepatitis A virus (HAV) infection. However, the mechanisms related to the effects of CB on Treg function in the course of hepatotropic viral diseases have not been elucidated. T cell immunoglobulin domain and mucin domain 3 (TIM-3), via its interactions with galectin-9 (GAL-9), is a receptor associated with enhanced Treg function. Thus, TIM-3 expression may be related to the crosstalk between CB and Tregs during HAV infection. Herein, in vitro treatment with high concentrations of CB upregulated TIM-3 expression on Tregs from healthy donors. CB treatment in vitro did not induce de novo Treg generation, and in vitro stimulation with TGF-ß, which shows increased secretion during HAV infection, resulted in a trend toward increased TIM-3 expression on Tregs and CD4+ T lymphocytes (TLs) from healthy donors. Interestingly, an upregulation of TIM-3 expression on CD4+CD25+ T cells and an increase in the proportion of CD4+ TLs expressing GAL-9 were found in HAV-infected patients with abnormal CB values relative to healthy controls. In addition, a statistically significantly reduction in IL-17F production was observed after treatment of CD4+ TLs from healthy donors with high doses of CB in vitro. In summary, our results suggest that CB might regulate Treg activity via a TIM-3-mediated mechanism, ultimately leading to an anti-inflammatory hepatoprotective effect.

Frequency and prognosis of acute pancreatitis associated with fulminant or non-fulminant acute hepatitis A: A systematic review.

BACKGROUND: Acute pancreatitis (AP) in patients with fulminant viral hepatitis is well recognized and its mortality depends on the severity of hepatitis rather than pancreatitis. Acute pancreatitis associated with non-fulminant acute hepatitis A (AHA) has been rarely described, and is considered to have a benign course with good response to conservative management. OBJECTIVE: To perform a systematic review of the frequency and prognosis of AP associated with fulminant or non-fulminant AHA. RATIONALE: An increasing number of reports describe AP associated with AHA. Some life-threatening complications related to AP may occur, and death has been reported. In addition, it is possible that early diagnosis of these cases may help in reducing the morbidity and mortality. DATA SOURCES: Ovid Medline In-Process & Other Non-Indexed Citations, Ovid MEDLINE, Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, Scopus, Google Scholar, and reference lists of relevant articles. STUDY SELECTION: All available studies discussing AP associated with fulminant or non-fulminant AHA. DATA EXTRACTION AND ASSESSMENT: Two blinded independent observers extracted and assessed the frequency of AP associated with AHA based on large studies including all cases of AHA observed during a prolonged period of time, diagnosis of AHA based on anti-HAV IgM, diagnosis of fulminant hepatitis (FH) based on the American Association for the study of Liver Diseases (AASLD) position paper, diagnosis of AP based on the American College of Gastroenterology (ACG) guidelines, diagnosis of AP associated with AHA based on Makharia's association, and diagnosis of AP severity based on the Revision of the Atlanta Classification (RAC). We have developed a tool for risk of bias assessment of case reports and case-series and applied it to the included studies. RESULTS: The frequency of reported AP associated with AHA is 0-0.1%. Thirty-eight publications with a total of 54 patients meeting the inclusion criteria have been published. Twenty-two studies had a low risk for bias, 10 had moderate risk and 6 had high risk. Patients originated from all continents but most of them were from Asia. The median age at diagnosis was 16 years (range: 2-81) with a male to female ratio of 2. The median interval between the onset of jaundice and onset of AP pain was 4 days (range: 0-30). AP was severe in 9% of patients. The median hospital stay for AP was 8 days (range: 3-35). Most cases occur in patients without FH (94%). Mortality was reported in 2 patients (3.7%). CONCLUSION: Acute pancreatitis associated with AHA is rare with an estimated frequency of 0-0.1%. Fifty-four documented cases, mostly in Asian patients, have been reported. The median age of patients is 16 years with a M/F ratio of 2. Acute pancreatitis occurs less than one week after the onset of jaundice and mostly in patients without FH. Acute pancreatitis in this setting is severe in 9% of patients with a mortality rate similar to all other causes of AP.

Hepatitis A virus genotype IA-infected patient with marked elevation of aspartate aminotransferase levels.

We describe a case of acute liver failure (ALF) without hepatic encephalopathy with marked elevation of aminotransferase due to hepatitis A, according to the revised Japanese criteria of ALF. This liver biopsy of the patient showed compatible to acute viral hepatitis and she immediately recovered without intensive care. She had no comorbid disorders. Of interest, phylogenetic tree analysis using almost complete genomes of hepatitis A virus (HAV) demonstrated that the HAV isolate from her belonged to the HAV subgenotype IA strain and was similar to the HAJFF-Kan12 strain (99% nucleotide identity) or FH1 strain (98% nucleotide identity), which is associated with severe or fulminant hepatitis A. Careful interpretation of the association between HAV genome variations and severity of hepatitis A is needed and the mechanism of the severe hepatitis should be explored.

MAVS-dependent host species range and pathogenicity of human hepatitis A virus.

Hepatotropic viruses are important causes of human disease, but the intrahepatic immune response to hepatitis viruses is poorly understood because of a lack of tractable small- animal models. We describe a murine model of hepatitis A virus (HAV) infection that recapitulates critical features of type A hepatitis in humans. We demonstrate that the capacity of HAV to evade MAVS-mediated type I interferon responses defines its host species range. HAV-induced liver injury was associated with interferon-independent intrinsic hepatocellular apoptosis and hepatic inflammation that unexpectedly resulted from MAVS and IRF3/7 signaling. This murine model thus reveals a previously undefined link between innate immune responses to virus infection and acute liver injury, providing a new paradigm for viral pathogenesis in the liver.

[Q fever : A rare differential diagnosis of granulomatous disease]. / Q-Fieber : Eine seltene Differenzialdiagnose granulomatöser Erkrankungen.

Q fever is a worldwide distributed zoonotic disease with a mostly benign course, which regularly reoccurs in Germany. This report is about a patient with sporadic serologically proven Q fever, which also showed typical histopathological findings with nonspecific granulomatous hepatitis, usually seen in acute disease. The bone marrow biopsy revealed so-called doughnut granulomas, which are not pathognomonic but a typical finding in Q fever. This case report impressively underlines that the histomorphological findings can make a decisive contribution to the clarification by extended differential diagnostics, even though it plays a subordinate role in the routine diagnostics of disseminated Q fever.

Auxiliary Liver Transplantation for Acute Liver Failure.

BACKGROUND: Auxiliary partial orthotopic liver transplantation is a technique where part of diseased native liver is removed and replaced with healthy donor liver so that, the left behind native liver could later regenerate. CASE CHARACTERISTICS: 2 year 6 month old girl with acute liver failure due to Hepatitis A. She underwent a successful auxiliary partial orthotopic liver transplantation. OUTCOME: Successful native liver regeneration and immunosuppression withdrawal after two and half years of surgery. MESSAGE: In selective cases of acute liver failure, auxiliary partial orthotopic liver transplantation could provide a chance for native liver regeneration and immunosuppression-free life.