Associations with efficacy and toxicity: peak blood CAR⁺ cells, serum cytokines. (A) There was a trend toward an increase in peak blood CAR⁺ cells with increasing dose levels (DL). Bracketed vertical lines represent interquartile range. Horizontal bars represent medians throughout. Blood concentration of CAR⁺ cells was determined by real-time quantitative PCR as described in “Methods.” (B) There was no significant difference in peak blood CAR⁺ cells for patients with SD or PD compared with patients who had CR or PR. (C) There was no difference in the area under the curve (AUC) of blood CAR⁺ cells for patients with SD or PD compared with patients who had CR or PR. AUC was calculated including all measures up to, and including, day +30 after CAR T-cell infusion. (D) Patients experiencing CRS had significantly higher peak levels of blood CAR⁺ cells than patients who had no CRS. (E) Patients experiencing rashes had a significantly higher peak levels of blood CAR⁺ cells than patients who had no rashes. For panels B-E, all statistics were by Mann-Whitney U test; P < .05 is considered statistically significant. (F) Peak levels of 10 serum cytokines for all patients. Serum levels of the following cytokines were higher in patients experiencing CRS vs patients who had no CRS: (G) IFN-γ, (H) IL-10, (I) IL-2, (J) IL-6, and (K) TNF-α. (L) Patients experiencing rashes had significantly higher peak serum IL-6 levels than patients who had no rashes. For panels G-L, statistical comparisons were by the Mann-Whitney U test with Bonferroni correction for multiple comparisons; P < .005 is considered statistically significant. IFN-γ, interferon gamma; TNF-α, tumor necrosis factor α.