Eligible patients who were diagnosed with EBV-HLH or CAEBV, age between 12 and 70 years, were enrolled in this study. All of them need to sign the informed consent first.~PD-1 monoclonal antibody 200mg is infused intravenously once for patients whose age >=18 years, or age <18 years but weight >=40kg. While for patients age <18 years, the dose of PD-1 monoclonal antibody is 3mg/kg. Besides, optimal supportive care is necessary.~Ruxolitinib and/or low-dose glucocorticoid can be used to reduce inflammation.~Cerebrospinal fluid parameters are examined, and methotrexate 15mg combined with dexamethasone will be intrathecal injected without contraindications.~Clinical and laboratory indicators are investigated weekly to evaluate the efficacy and toxicity.~If patients achieve partial response/complete response within 14 days after PD-1 monoclonal antibody, the clinical observations are stopped. If not, the observation period is prolonged to 21 days.~If disease progress at day 21, this study is terminated, and the patient should be transfer to other treatments as soon as quickly.
EBV-HLH and CAEBV are both caused by EBV infection, part of them can rapidly lead to a syndrome of severe, life-threatening hyper-inflammation, with poor prognosis. Currently, the most effective treatment remains unknown. This study is trying to evaluate the efficacy and safety of PD-1 monoclonal antibody as a first-line therapy for EBV-HLH and CAEBV.