Correlative studies of cellular populations and proteins from CSF demonstrate a marked absence of inflammatory signature. (A) CSF volume and cell counts for 2 patients with spinal paresis after CART at the time of symptoms and 2 patients who received CART but did not develop symptoms of ICANS. Proportion of cell types determined by flow cytometry of each lineage distribution (B) and T-cell distribution (C) were similar between all 4 patients. Proportion of CD4 (D) and CD8 (E) cells with flow cytometry evidence of activation were similar between all 4 patients. (F) Volcano plot (adjusted P > .05, log fold change >0.5) demonstrating differentially expressed proteins measured from D28 CSF in patients who developed quadriparesis or paraparesis (N = 4) and patients treated with CART19 or CART22 who did not (N = 150). The top 2 differentially expressed proteins were interferon gamma (G) and CCL17 (H), and were lower in patients who developed paresis (N = 4) than in those who developed any other phenomenology of ICANS (N = 78). ID, identifier.