An Active Cytomegalovirus Infection and Epstein-Barr Virus Reactivation Complicated by Cytomegalovirus Meningitis and Virus-Associated Hemophagocytic Lymphohistiocytosis during Methotrexate and Upadacitinib Therapy in a Patient with Rheumatoid Arthritis.

Methotrexate (MTX) and Janus kinase (JAK) inhibitors are effective treatments for rheumatoid arthritis (RA); however, they may increase the risk of opportunistic infections. We herein report a case of a patient with RA receiving MTX and upadacitinib who developed an active cytomegalovirus (CMV) infection and Epstein-Barr virus (EBV) reactivation, complicated by CMV meningitis and virus-associated hemophagocytic lymphohistiocytosis (HLH). This case highlights that clinicians should consider not only herpes zoster, but also infection or reactivation involving non-VZV herpesviruses, including CMV and EBV, particularly in patients receiving JAK inhibitors in combination with other immunosuppressive agents.