Cytomegalovirus Enteritis in a Patient with Rheumatoid Arthritis Receiving Baricitinib.

T cells play a central role in immunity against cytomegalovirus (CMV)1. Baricitinib, a Janus kinase (JAK) inhibitor, suppresses T cell function by inhibiting JAK-signal transducers and activators of transcription (STAT)2. Interferon-γ (IFN-γ) is one of the major T cell cytokines involved in the immunity against CMV3. Tacrolimus has a strong inhibitory effect on IFN-γ as well as JAK inhibitors4. A 65-year-old male with a 14-year history of …