Abstract: Objective　To investigate the clinical characteristics, family history, as well as the efficiency and prognosis of children with HLH diagnosed and treated by HLH-2004 regime. Methods　A total of 40 children with HLH diagnosed in Xuzhou Children’s Hospital from January 2011 to December 2014 were enrolled. Clinical data including family history, clinical characteristics, laboratory results, treatment and prognosis were retrospectively analyzed. Results Among the 40 children with HLH, 24 were males and 16 were females. The median age was 1 year old (range from 4 months to 10.5 years old). Two cases had positive family history, 27 cases had known primary diseases, while 13 cases had no clear reasons. Main clinical manifestations included fever, hepatosplenomegaly, bleeding, pulmonary infiltration, pleural effusion, central nervous system lesions, rash and so on. Main laboratory abnormalities were cytopenia, abnormal liver function, coagulation abnormalities, hypertriglyceridemia, elevated ferritin, hemophagocytosis in bone marrow. There were 35 cases treated with HLH-2004 regimen, 26 cases survived and 14 cases died. The main causes of death were infection, disseminated intravascular coagulation and multiple organ failure. Conclusion　HLH in Chinese children is an aggressive syndrome with complicated manifestations. Treatment with HLH-2004 regime resulted in a relatively good prognosis.

Key words: HLH-2004 regimen;　hemophagocytic lymphohistiocytosis;　child