BCR and acute lymphoblastic leukemia: After exposure to varying concentrations of PLGA-NHS or CD19@NP for 24 h or 48 h in vitro, no significant effects on the viability of various cell types were observed including murine A70.2 pre-B cells, RAW 264.7 macrophages, primary BCR-ABL1+ B-ALL cells, A20 B lymphoma cells, EL4 T cells, and NIH/3T3 fibroblast cells (Figure 2F-G, Figure S3B-C).