In a retrospective analysis of 118 patients receiving anti-CD19 CAR T cell therapy for the treatment of either B-ALL or LBCL, the m-EASIX score prior to infusion was associated with onset of any grade and severe CRS, and m-EASIX score on days +1 and +3 post-infusion were associated with onset of severe CRS. Here, CD19 is linked to acute lymphoblastic leukemia.