Abstract: Objective To investigat the clinical features of adult-onset chronic active Epstein-Barr virus infection(CAEBV)and to provide a basis for the diagnosis and treatment of CAEBV.Methods The clinical data of 41 adults with CAEBV from January 2008 to December 2019 was analyzed retrospectively, including onset, clinical manifestation, EBV DNA, EBV antibodies, cytokines, EBER in situ hybridization, treatment and follow-up results. Results Among the 41patients with CAEBV, the male to female ratio was 1.2∶1(22 males and 19 females), and the median age was 42 years(15-75 years). According to the analysis of the onset of the patients, 38 cases (92.7%), 36 cases (87.8%), 35 cases (85.4%) and 28 case (68.3%) of the patients presented intermittent fever, accompanied by lymph node enlargement, splenomegaly and hepatomegaly, with the most common involvement of the digestive, respiratory and blood systems. Life-threatening complications included 9 cases (21.9%) of hemophagocytic syndrome, 5 cases (12.2%) of liver failure, 4 cases (9.8%) of ARDS caused by interstitial pneumonia, and 3 cases (7.3%) of malignant lymphoma. The mean value of serum EBV DNA in 41 CAEBV patients was 104.3copy/ml. Eleven of the 41 cases (26.8%) died within 3 months. The platelet counts (53.3±29.2)×10⁹/L vs(88.1±36.7)×10⁹/L in death group was significantly lower than survival group (t=3.055, P ±0.01). At the same time serum TBil levels(141.4±78.5)μmol/L vs(61.3±34.4)μmol/L,AST(210.5±99.6)IU/L vs(78.8±89.2)IU/L,LDH(864.6±478.6)IU/L vs (445.2±337.5)IU/L,ferritin(1933.9±166.7)ng/mL vs(687.5±103.8)ng/mL, IL-2R(5 253.6± 736.4)U/L vs(1 989.0± 131.5)U/L,IL-10(486.1±125.7)pg/mL vs(151.2 ±232.5)pg/mL in death group were all significantly higher than survival group(t=-3.759、-3.542、-4.715、-6.672、-3.965 and -3.452,all P<0.01).Conclusion The study reveals that CAEBV in adult patients has a severe clinical course and prognosis is poor. Lower thrombocytopenia and higher TBil、AST、LDH、ferritin、IL-2R and IL-10 might potentially be risk factor for a poor prognosis. EBV loads should be measured and tissue should be stained on hybridization (EBER) if a patient presents with the known symptoms of CAEBV.

Key words: Chronic active Epstein-Barr virus infection(CAEBV), Hematophagous lymphocyte hyperplasia (EBV-HLH), Cytokines, EBER in situ hybridization