Abstract: ObjectiveTo study the clinical and laboratory characteristics, treatment and follow-up results of chronic active Epstein-Barr virus infection（CAEBV）in children and to provide a basis for the diagnosis and treatment of CAEBV. MethodsThe clinical data of 18 children with CAEBV from Jan 1st, 2010 to Dec 31st, 2017 was analyzed retrospectively, including onset, clinical manifestation, EBV DNA, EBV antibodies, cytokines, treatment and follow-up results. ResultsThe onset of the disease was EBV recurrent infection at the time of first hospitalization in 13 cases, and EBV-hematophagous lymphocyte hyperplasia (HLH) in 5 cases. The common clinical manifestations were fever, hepatosplenomegaly, and lymphadenopathy. Laboratory tests showed that elevated transaminase and cytopenia were common. The anti-EB VCA-IgG antibodies were positive, while the IgM antibodies were negative in 18 cases. EBV DNA in peripheral blood(18/18), bone marrow(14/14) and biopsy sample(live: 1/4, lymphonodus: 2/3) was positive. Plasma levels of several cytokines, including IL-4,IL-10 and IFN-γ,elevated in different degrees in persons with CAEBV, while the ratio of B cells, total T cells, CD8+T cells, and NK cells in peripheral blood decreased. The patients had mainly received antiviral drugs, intravenous immune globulin, immunosuppressive agents, multi-drug chemotherapy, rituximab, and HSCT. Among 17 CAEBV patients followed up,14 cases died. The patients with EBV-associated HLH had significantly shorter survival time. ConclusionThe children with CAEBV infection had poor prognosis and high mortality due to the variety of onset, clinical manifestation and treatment. The specific changes of EBV DNA, antibody profiles, cytokines and lymphocyte subsets may be helpful in the early diagnosis and targeted therapy of CAEBV.