1. INTRODUCTION
Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the most effective curative therapy for several hematological malignancies and bone marrow failure disease in pediatric patients. However, transplantation-related complications provide a serious threat to the long-term survival of patients, one of which is transplantation-associated thrombotic microangiopathy (TA-TMA). TA-TMA is characterized by microvascular hemolytic anemia and thrombocytopenia1. The fundamental trigger to onset of TA-TMA is vascular endothelial injury. In addition to the widening of the sub-endothelial space and platelet thrombosis, multiple organ dysfunction also tends to occur particularly of the kidney, heart, intestine, lungs, and brain2. Currently, the diagnosis and treatment of TA-TMA in pediatric patients is still in the exploratory stage. In this paper, we retrospectively analyzed the clinical characteristics of 20 pediatric patients with TA-TMA, and hereby present the diagnosis, clinical sequelae, and outcomes.