Biomarkers for early prediction of grade ≥4 CRS. (A-H) Concentrations of listed cytokines in serum obtained from patients at the indicated time points. P values were determined by using the Kruskal-Wallis test. (I) An algorithm for early identification of patients at high risk of grade ≥4 CRS using classification-tree modeling. Early high fever (≥38.9°C) within the first 36 hours after CAR T-cell infusion triggers evaluation of serum MCP-1 concentration. Patients with fever ≥38.9°C and serum MCP-1 ≥1343.5 pg/mL are at high risk for subsequent development of grade ≥4 CRS. ***P < .0001; **P ranges from >.0001 to <.001; *P ranges from >.001 to <.005.