HSV-2–related hemophagocytic lymphohistiocytosis in a fingolimod-treated patient with MS

Abstract

Fingolimod is an oral, disease-modifying therapy used to treat multiple sclerosis (MS).1 However, severe viral infections, including disseminated varicella-zoster virus infection,1 herpes simplex encephalitis,1,2 varicella-zoster virus encephalitis and vasculopathy,3 or progressive multifocal leukoencephalopathy,4 have been reported during fingolimod therapy. Hemophagocytic lymphohistiocytosis (HLH), often triggered by certain viral infections, is a fatal disease characterized by fever, pancytopenia, elevated liver enzymes, hyperferritinemia, hepatosplenomegaly, and hemophagocytosis.5 A triggering infection causes persistent activation of lymphocytes and histiocytes, resulting in exaggerated immune responses and hemophagocytosis. We describe an autopsied case of disseminated herpes simplex virus type 2 (HSV-2) infection presenting with HLH, following 0.5 mg fingolimod and corticosteroid therapies. Acknowledgment: The authors thank the patient and his family for their cooperation regarding this report. This case report was approved by the ethical committee of Anjo Kosei Hospital. The authors obtained written informed consent from the patient's family for this publication.