Pretreatment humoral immunogenicity and maximum fold change in anti-mCAR19 antibodies posttreatment by response category. Baseline anti-mCAR19 antibody levels (A-D) and maximum fold change in posttreatment anti-mCAR19 antibody levels (E-H) (by MFI) by response category. CRi, CR with incomplete blood count recovery; NR, no response; PR, partial response; PD, progressive disease; SD, stable disease.