Abstract: Objective　To explore the clinical characteristics and prognosis of severe adenovirus infection with hemophagocytic lymphohistiocytosis (HLH). Method　The clinical data of severe adenovirus infection combined with HLH in 7 children from January 2018 to December 2019 were collected and analyzed. Results　Among the 7 cases (4 males and 3 females) aged from 3 months to 16 months, the nasopharyngeal swabs and bronchoalveolar lavage fluid were positive multiple times for respiratory adenovirus antigens in the early stage of admission. All the 7 children had cough, high fever, and mild to moderate hepatosplenomegaly. Four had respiratory failure. Two had subcutaneous emphysema and mediastinal emphysema. All of the children were diagnosed with severe pneumonia. Two cases were diagnosed with HLH within one week of admission. Four cases were diagnosed with HLH within 7~14 days of admission and one case was diagnosed with HLH within 26 days of admission. Conclusions　Severe adenovirus infections are more common in infants and children under 2 years of age. If the child has fever for more than 1 week, that pancytopenia, varying degrees of albumin decrease, ferritin increase, lactate dehydrogenase increase, and liver enzyme increase occur at the same time, is positive indicators for early detection of severe adenovirus infection with HLH.

Key words: 　adenovirus;　hemophagocytic lymphohistiocytosis;　immunotherapy;　severe pneumonia