Abstract： Objective To analyze the clinical characteristics of Mycoplasma pneumoniae-associated hemophagocytic syndrome (MP-HLH).Method A retrospective investigation of the clinical manifestation,laboratory test,imagelogy,clinical course and outcome of 3 cases with MP-HLH seen between June 2013 and July 2013 in Shenzhen Children's Hospital,and review of relevant literature were conducted.Result Of the 3 cases of MP-HLH,2 were males,one was female,the ages were 1 year,3 years and 6 years,respectively.They had no underlying disease previously.All the 3 cases had onset of fever,cough as main symptoms.Diagnosis of refractory Mycoplasma pneumoniae pneumonia was made,which was accompanied by decreased neutrophils [(0.08-0.68) × 109/L],hemoglobin [(79-103) g/L],platelet [(64-157) × 109/L],plasma fibrinogen [(1.3-1.5)g/L],lactate dehydrogenase [(1 170-1 285) U/L] and increased serum ferritin [(936.7-39 789.0) μg/L] in the third week of course.In two cases the T lymphocytes decreased,and the NK cell activity decreased significantly in one.Bone marrow cytology showed prompted bone marrow hyperplasia,and the phenomenon of phagocytosed blood cells.CT scan was performed for all the cases and consolidation with pleural effusion were shown.Two cases were admitted to PICU,and required endotracheal intubation and mechanical ventilation.Flexible bronchoscopy and bronchial lavage were performed and bronchial cast was found in two cases.All of them were treated with macrolide combined with other antibiotics,glucocorticoids and gamma globulin combination therapy,including one case given dexamethasone [10 mg/ (m2 · d)],cyclosporine[6 mg/(kg· d)],etoposide [150 mg/ (m2 · d)]chemotherapy.Two cases were cured,and 1 case died.The authors summarized the 18 cases reported in domestic and foreign literature.Foreign children were diagnosed and treated with steroids in 1-2 weeks,and 10 cases were cured,and 2 cases died.They died of massive hemorrhage and meningoencephalitis,and domestic children were diagnosed and treated within two to 4 weeks after onset,5 cases were cured,one case died of severe pneumonia.Conclusion MP-HLH is a rare disease in children,and had acute onset,rapid progression and high mortality.Early treatment with steroids was associated with a good prognosis,the key to successful treatment is early diagnosis and treatment,avoiding the immune cascade.Too late a diagnosis or development of serious complications may lead to death.