GM-CSF neutralization in vivo ameliorates NI after CART19 cell therapy in a xenograft model. (A-B) Gadolinium-enhanced T1-hyperintensity (cubic millimeters) MRI showed that GM-CSF neutralization helped to reduced brain inflammation, blood–brain barrier disruption, and possible edema compared with isotype control. (A) Representative images. (B) Three mice per group. Data are mean ± SD. *P < .05, **P < .01, 1-way analysis of variance. (C) Human CD3 T cells were present in the brain after treatment with CART19 cell therapy. GM-CSF neutralization resulted in a decreased raw average of CD3 infiltration in the brain (although not statistically significant), as assayed by flow cytometry in brain hemispheres; 3 mice per group. Data are mean ± SEM. *P < .05, Student t test. (D) CD11b⁺ bright macrophages were decreased in raw average (although not statistically significant) in the brains of mice receiving GM-CSF neutralization during CAR-T cell therapy compared with those receiving isotype-control treatment during CAR-T cell therapy, as assayed by flow cytometry in brain hemispheres; 3 mice per group. Data are mean ± SEM, Student t test.