PD-1 Blockade-Induced Hemophagocytic Lymphohistiocytosis, a Dilemma Therapeutic Outcome in 2 Patients with CAEBV: A Case Series.

Hemophagocytic lymphohistiocytosis (HLH), whether primary or secondary, is a rare and fatal clinical syndrome of uncontrolled immune activation and inflammatory cascade. Immune checkpoint inhibitors (ICIs) induced HLH has no standard diagnostic and treatment guidelines. Early diagnosis and appropriate treatment according to different disease backgrounds are crucial. Herein, we first report 2 cases of patients with chronic active Epstein-Barr virus infection (CAEBV) who developed HLH after the use of sintilimab, a monoclonal antibody against programmed cell death protein 1 (PD-1), and the DEP (liposomal doxorubicin, etoposide, methylprednisolone) chemotherapy regimen in combination with ruxolitinib were used to successfully control the disease.