CD19 and leukemia: In particular, CD40L-expressing CD19 G2 CAR-T cells displayed potent anti-tumor activity in CD19/CD40 double-positive A20 lymphoma-bearing BALB/c mice as well as in mice with CD40-negative leukemia cells, proving that the CD19-targeted CD40L-expressing CAR-T cells also function without CD40/CD40L-mediated cytotoxicity [102].