[Severe Hepatitis E virus infection in a patient with rheumatoid arthritis treated with baricitinib].

A patient with rheumatoid arthritis (RA) was presented, who developed an infection with the hepatitis E virus (HEV) under treatment with the Janus kinase (JAK) 1 and 2 inhibitor baricitinib. In the 3‑month routine check-up the patient had clearly elevated transaminase levels with an inconspicuous physical examination. The investigations detected antibodies of IgM and IgG classes against HEV and an elevated C‑reactive protein (CRP) level as well as HEV-RNA by real-time PCR, which is indicative of a recent HEV infection. Baricitinib was immediately discontinued. The extensive anamnesis revealed that the patient had eaten beef tartar some days before the consultation, without the occurrence of gastrointestinal symptoms or fever. In the further course the patient completely recovered and the liver function tests and the CRP levels normalized within 3 months. Baricitinib was then restarted. So far only few reports have been published on HEV infections in RA patients who have been treated with JAK inhibitors.