The major findings in our study were: 1)PICU admission after CAR-T therapy in pediatric patients with ALL is frequent, mainly due to CRS; 2)as previously described, high tumor burden is a risk factor for severe CRS and ICANS and, therefore, PICU admission; 3)supportive treatment allowed effective management of toxicities with high survival; 4)relapse was more frequently CD19 negative among patients admitted to PICU; 5)unfavorable outcome after PICU discharge was more frequent among patients requiring intensive care management (59% vs. 17%). This evidence concerns the gene CD19 and acute lymphoblastic leukemia.