Janus kinase-Inhibition modulates hepatitis E virus infection
Background: Human hepatitis E virus (HEV) usually causes a self-limiting disease, but especially immunocompromised individuals are at risk to develop a chronic and severe course of infection. Janus kinase (JAK) inhibitors (JAKi) are a novel drug class for the treatment of autoimmune inflammatory rheumatic disease (AIRD). As JAKs play a key role in innate immunity, viral infections and reactivations are frequently reported during JAKi treatment in AIRD patients. The aim of this study was to characterize the influence of JAKis on HEV replication in vivo and in authentic cell culture models ex vivo.   Methods: We evaluated liver enzymes of an AIRD patient under JAKi therapy with hepatitis E and HEV infections in a cohort of  AIRD patients. Experiments with HEV were performed by infection of primary human hepatocytes (PHHs) followed by immunofluorescence staining of viral markers and transcriptomic analysis.    Results: Acute hepatitis was observed in a patient with AIRD and concomitant HEV infection. No acute infection could be detected in the AIRD cohort.  Infection experiments in PHHs displayed an up to 50-fold increase of progeny virus production during JAKi treatment and transcriptomic analysis revealed induction of antiviral programs  during infection. This induction  was perturbed in the presence of JAKis, concomitant with elevated HEV RNA levels.  Conclusion:  Therapeutic JAK inhibition increases HEV replication by modulating the HEV-triggered immune response. Therefore, clinical monitoring of HEV infection during JAKi treatment and in case of elevated liver enzymes should be considered. Overall design: Plated primary human hepatocytes (PHH) of one representative donor were inoculated with HEV-3 p6 (MOI=1) and treated with 200 nM or 2 uM baricitinib for 72h.