This Penn grading scale has been applied to CLL, ALL, and diffuse large B cell lymphoma (DLBCL) [7, 16]; has been implemented in numerous multicenter, global clinical trials across North America, Europe, Asia, and Australia [8, 9, 20, 21]; and is being used to grade CRS associated with several different types of CAR T cell therapies, including CAR T cells targeting antigens other than CD19 and humanized CAR T cell therapies [22, 23]. This evidence concerns the gene CD19 and B-cell chronic lymphocytic leukemia.