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

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.

Zoonotic Hepatitis E Virus: An Ignored Risk for Public Health

“…Taken together, these observations are consistent with results of a study showing that constant suppression of HEV-specific cell mediated immune responses by administration of immunosuppressants establishes chronic HEV infection in a swine model ( Cao et al, 2017 ). In addition, a pilot study demonstrated that cynomolgus monkeys could be persistently infected by a genotype 3 hepatitis E virus isolate after long-term immunosuppressive drug administration, a result similar to that obtained in swine ( Gardinali et al, 2017 ). Ultimately, these animal models will be useful tools for future development of therapy for chronic HEV infection.…”

“…In addition to viral determinants, host factors, especially host immune status, may contribute to cross-species transmission of zoonotic HEV and HEV host tropisms. This is supported by establishment of HEV chronicity is animal models by administration of immunosuppressive drugs to animals or infection of another virus impairing immune system ( Salines et al, 2015 ; Cao et al, 2017 ; Gardinali et al, 2017 ). Conversely, infection of organ transplantation receipt by camel HEV raises an interesting question regarding whether host immune status affects cross-species transmission of HEV ( Lee et al, 2016 ), which is also consisted with observation that genotype 3 HEV could establish chronicity in a human liver chimeric mouse model (uPA +/+ Nod-SCID-IL2Rγ -/- )( van de Garde et al, 2016 ).…”

Pig model mimicking chronic hepatitis E virus infection in immunocompromised patients to assess immune correlates during chronicity

“…Were the chronically infected pigs kept for a longer period, it is possible that significant pathological liver lesions might develop gradually because of repeated viral-induced injury in the liver. In fact, a recent study reported more pronounced hepatic lesions in HEV-infected cynomolgus monkeys that received long-term (160-d) immunosuppressive treatment with tacrolimus (31).…”

Cynomolgus monkeys (Macaca fascicularis) experimentally and naturally infected with hepatitis E virus: The bone marrow as a possible new viral target

“…High doses of tacrolimus showed to promote infection of liver cells with HEV in cell culture models [ 10 ]. It is considered a risk factor for virus persistence in the host [ 11 , 12 ]. Also, occurrence of HEV-3 related chronic hepatitis was reported in recipients of allogeneic bone marrow transplantation [ 13 – 15 ].…”

“…Cynomolgus ( Macaca fascicularis ) is the best model to mirror human organ transplantation [ 25 , 26 ]. Besides, it is considered the primary model for studying acute and chronic clinical course of HEV infection, as confirmed by our group [ 12 ].…”