Objective: To investigate the efficacy of CD19-targeted chimeric antigen receptor T-cell (CD19-CAR T) in the treatment of patients with refractory relapsed B cell acute lymphocyte leukemia（B-ALL）.
Methods: The efficacy and safety of CD19-CAR T cells in treatment of patients with refractory relapsed B-ALL from January 2015 to July 2017 in the Department of Hematology of Peking University Third Hospital were analyzed retrospectively.
Results: A total of 10 patients were included in this analysis, all of which were consistent with the diagnosis of refractory relapsed B-ALL, and the immunophenotype of leukemia cells was CD19 positive. After treatment with CD19-CAR T cells, the overall response rate（ORR） on day 28 was 70%. Among them, 6 cases reached complete remission（CR）, 1 case reached partial remission（PR）. The rate of CR on day 90 was 30%.
Conclusion: CD19-CAR T cells are effective in the treatment of refractory relapsed B-ALL, and the adverse reactions are controllable.