Abstract:Objective: To explore the clinical etiology and prognosis of hemophagocytic lymphohistiocytosis (HLH). Methods: Clinical information of 56 patients with HLH was reviewed. The frequency and distribution of general information, clinical characteristic and clinical pathogen were analyzed. Survival curve by Kaplan-Meier method and log-rank test were utilized for analysis of survival time and comparison of prognosis respectively. Results: Lymphoma was the most common cause (32.14%), followed by infection (30.36%), among which EBV infection was the most common (16.07%). Autoimmune diseases accounted for 17.86%, and primary HLH accounted for 12.50%. The survival rates of 56 patients with HLH in the 1st, 3rd, 6th, 9th, 12th, 18th month were 71.4%, 48.2%, 42.9%, 41.1%, 37.5% and 28.6% respectively. The survival curves of each etiology group were different. The survival rate of autoimmune disease group were significantly higher than that of other groups. EBV-HLH patients had lower survival rate than uninfected patients. Patients without etoposide had lower survival rate than users, and there was no significant difference in the survival rate between patients who used ruxolitinib and those who did not. Conclusion: Lymphoma is the most common cause of HLH. The incidence and survival rate of HLH are different with different causes. EBV-HLH patients have low survival rates and poor prognosis. The use of etoposide can improve the survival rate of patients, but ruxolitinib can’t.