Bystander CAR T cells can be detected in a validation cohort of 4 additional NHP. (A) UMAP with shared nearest-neighbor clustering across 4 additional animals, colored to identify 23 transcriptional clusters. (B) Bystander score determined by applying bystander signature 1 to each cluster using decoupleR. (C) Heat map of row-scaled normalized expression averaged across each cluster for the top 10 upregulated and downregulated genes identified in bystander signature 1. (D) Composition of each cluster by animal, with an arrow highlighting cluster 22, the cluster with the highest signature score when applying bystander signature 1. (E) Composition of clusters based on sample collection time point, with an arrow highlighting cluster 22, the cluster with the highest signature score when applying bystander signature 1.