Cynomolgus monkeys are successfully and persistently infected with hepatitis E virus genotype 3 (HEV-3) after long-term immunosuppressive therapy

PLoS One. 2017 Mar 22;12(3):e0174070. doi: 10.1371/journal.pone.0174070. eCollection 2017.

Abstract

Epidemiological studies found that hepatitis E virus genotype 3 (HEV-3) infection was associated with chronic hepatitis and cirrhosis in immunocompromised patients. Our study aimed to investigate the relationship between the host immunosuppressive status and the occurrence of HEV-related chronic hepatitis. Here we describe a successful experimental study, using cynomolgus monkeys previously treated with tacrolimus, a potent calcineurin inhibitor immunosuppressant, and infected with a Brazilian HEV-3 strain isolated from naturally infected pigs. HEV infected monkeys were followed up during 160 days post infection (dpi) by clinical signs; virological, biochemical and haematological parameters; and liver histopathology. The tacrolimus blood levels were monitored throughout the experiment. Immunosuppression was confirmed by clinical and laboratorial findings, such as: moderate weight loss, alopecia, and herpes virus opportunistic infection. In this study, chronic HEV infection was characterized by the mild increase of liver enzymes serum levels; persistent RNA viremia and viral faecal shedding; and liver histopathology. Three out of four immunosuppressed monkeys showed recurrent HEV RNA detection in liver samples, evident hepatocellular ballooning degeneration, mild to severe macro and microvesicular steatosis (zone 1), scattered hepatocellular apoptosis, and lobular focal inflammation. At 69 dpi, liver biopsies of all infected monkeys revealed evident ballooning degeneration (zone 3), discrete hepatocellular apoptosis, and at most mild portal and intra-acinar focal inflammation. At 160 dpi, the three chronically HEV infected monkeys showed microscopic features (piecemeal necrosis) corresponding to chronic hepatitis in absence of fibrosis and cirrhosis in liver parenchyma. Within 4-months follow up, the tacrolimus-immunosuppressed cynomolgus monkeys infected with a Brazilian swine HEV-3 strain exhibited more severe hepatic lesions progressing to chronic hepatitis without liver fibrosis, similarly as shown in tacrolimus-immunosuppressed solid organ transplant (SOT) recipients. The cause-effect relationship between HEV infection and tacrolimus treatment was confirmed in this experiment.

MeSH terms

  • Animals
  • Brazil
  • Female
  • Genotype
  • Hepatitis Antibodies / immunology
  • Hepatitis E / immunology
  • Hepatitis E / virology
  • Hepatitis E virus / genetics
  • Hepatitis E virus / immunology
  • Hepatitis E virus / pathogenicity*
  • Immunosuppression Therapy / methods
  • Immunosuppressive Agents / immunology*
  • Liver / immunology
  • Liver / virology
  • Liver Cirrhosis / immunology
  • Liver Cirrhosis / virology
  • Liver Function Tests / methods
  • Macaca fascicularis / immunology*
  • Macaca fascicularis / virology*
  • Male
  • RNA, Viral / genetics
  • Virus Shedding / immunology

Substances

  • Hepatitis Antibodies
  • Immunosuppressive Agents
  • RNA, Viral

Grants and funding

Support was provided by Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), grants awarded to AMCG (E-26/110.848/2013); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), grants awarded to MAP; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), fellowship awarded to NRG; and FIOCRUZ –PASTEUR Program, budget awarded to MAP within the framework of the call 2013/2015. Libbs Indústria Farmacêutica provided, as a donation, the tacrolimus medicine, the immunosuppressive used in the present study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Libbs Indústria Farmacêutica provided support in the form of salaries for author EU, and Dr. Julio Moran Laboratories for author JM but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.