Abstract: The present invention relates to the neurotoxicity that can occur as a side effect of the treatment of cancer patients with redirected T-cell therapies, such as chimeric antigen receptor (CAR) T cell therapies. The present invention provides various methods and compositions useful for treating and/or preventing such neurotoxicity, and/or for determining whether a subject is likely to develop such neurotoxicity, as well as a variety of other methods and compositions relating to the neurotoxicity associated with redirected T-cell therapies.