Hepatitis E virus infection in immunosuppressed patients and its clinical manifestations

Hepatitis E virus (HEV) is a main cause of acute hepatitis globally. However, immunosuppressed patients regularly develop chronic courses. The aim of this study was to analyse the current status of HEV diagnostics, characterize clinical manifestations and identify risk factors for complicated HEV infections. In this retrospective study at two large hospitals, 512 patients with borderline and positive anti-HEV-IgM and 94 patients with positive HEV-PCR between January 1999 and May 2023 were included. Detection by anti-HEV-IgM-ELISA led to a positive HEV-PCR in only 17.9 %. Amongst patients with positive HEV-PCR, 61 had underlying immunosuppression and 23 were patients after solid organ transplantation (SOT). All 13 patients with chronic HEV infections were immunosuppressed. Generally, immunosuppression led to higher HEV-RNA concentrations and a higher probability of receiving immediate treatment. However, all fulminant courses with liver failure happened in patients without immunosuppression. Immunocompetent patients showed symptoms more frequently and primarily had higher bilirubin levels indicating more severe liver damage. A risk factor for delayed or failed viral clearance after SOT was the administration of mTOR inhibitors. Fulminant HEV infections happen primarily in immunocompetent patients. Nevertheless, immunosuppressed patients bear the risk of undetected, prolonged HEV infections, reflected by the rare occurrence of symptoms.