GFAP and NfL levels are elevated at baseline and increase in the CSF during ICANS. (A) Baseline biomarker measurements. Each point represents the data from 1 patient, all 3 cohorts are combined. Bars show the median. CSF samples were obtained prelymphodepletion and serum samples are from day 1 before CAR T-cell infusion. The dotted lines show the upper bound of published reference levels (1386 pg/mL for cGFAP, 380 pg/mL for cNfL, 25 pg/mL for sNfL). Groups were compared by Mann-Whitney test. (B) Pairwise comparisons of biomarker levels show rises of cGFAP and cNfL, but not sNfL during ICANS. Note that cGFAP decreased in patients without ICANS. Each linked set of data points is from 1 patient. The “pre” time point for cGFAP and cNfL represents the prelymphodepletion sample, the “acute” time points represent the sample obtained on days 5 to 15 post CAR T-cell infusion. For sNfL, “pre” represents samples obtained on day 1 and “post” represents samples obtained from days 7 to 10. Data were analyzed by Wilcoxon matching-pairs signed-rank test.