Hemophagocytic syndrome, also known as hemophagocytic lymphohistiocytosis (HLH).This disease is mainly caused by ineffective immunity leading to the activation of a large number of immune cells and the secretion of large amounts of cytokines, thereby causing progressive immune damage to the body.Usually, patients will have serious problems such as persistent fever, decreased blood count, hepatosplenomegaly, abnormal coagulation, and abnormal function of multiple organs. It is considered a critical disease with sudden onset, severe illness, rapid progression, and extremely high mortality rate. symptoms.Recently, the team of Deputy Director Bao Yongjian of the Department of Respiratory Medicine at Guangxi Jiangbin Hospital (Third People's Hospital of the Autonomous Region) cooperated with Difei Medical to perform mNGS testing on alveolar lavage fluid for a critically ill patient with repeated high fevers. The test results quickly identified EB virus infection. Hemophagocytic syndrome was diagnosed. After symptomatic treatment, the patient improved and was discharged from the hospital 11 days later and returned to school.The editor has compiled the cases as follows for clinical communication and learning.