Abstract: Provided are methods and articles of manufacture for use with cell therapy for the treatment of diseases or conditions, e.g., cancer, including for predicting and treating a toxicity. In some embodiments, the toxicity is a neurotoxicity or cytokine release syndrome (CRS), such as a severe neurotoxicity or a severe CRS. The methods generally involve detecting a marker by assaying a biological sample from a subject that is a candidate for treatment, optionally with a cell therapy, to determine if the subject is at risk for developing the toxicity, such as neurotoxicity or CRS or severe neurotoxicity or severe CRS. In some embodiments, the methods and articles of manufacture further includes a regent for assaying the biological sample and instructions for determining the percentage or number of cells positive for the marker in the biological sample.