To evaluate the antigen-specific expansion of CAR-T cells, 0.5 × 106 of CAR-T cells were co-cultured with an equal number of target cells (CD19+ cells - NALM6), and the proliferation of CAR-T cells was assessed using CAR-detection reagent where the proliferation of tumor cells was evaluated using CD19 marker by flow cytometry. The gene discussed is CD19; the disease is neoplasm.