Autopsy findings from the spinal cord (A-F) of patient 1 treated with CART22 and the brain and spinal cord (G-J) of patient 5 treated with CTL019, with both samples notable for white matter damage and an absence of lymphocytic inflammation. (A) Spinal cord showing pallor throughout all the white matter tracts (hematoxylin and eosin [H&E], 1× objective). (B) White matter of the cord showed extensive vacuolation, whereas the gray matter (bottom right) was relatively well preserved (H&E, 10× objective). (C) Numerous axonal spheroids (white arrows) were seen throughout white matter of the cord, indicating axonal injury (neurofilament immunostain, 20× objective). (D) Few macrophages were present within the white matter (CD68 immunostain, 10× objective). (E) Only extremely rare T lymphocytes (black arrow) were present within cord parenchyma (CD3 immunostain, 10× objective). (F) B lymphocytes were absent within the cord (CD79a immunostain, 10× objective). (G) White matter of the spinal cord was well preserved (H&E, 1× objective). (H) Cerebral cortex showing a region of pallor within the white matter (black arrow) (H&E, 1× objective). (I) Cortical white matter with vacuolation and gliosis (H&E, 20× objective). (J) Axonal swellings were seen within the white matter of the cerebral cortex, indicating axonal injury (β-APP immunostain, 10× objective).