The largest study of infectious complications after CD19-directed CAR T-cell therapy to date followed 133 patients with various malignancies (ALL, CLL, NHL) for up to 3 months after infusion; infection density was reported at 1.19 infections for every 100 days at risk within the first 28 days after cell infusion, and 0.67 between days 29 and 90 (21). This evidence concerns the gene CD19 and acute lymphoblastic leukemia.