TCL1A and tropical spastic paraparesis: Primarily, due to the unavailability of scRNA‐seq data from CSF cells in HAM patients, we were unable to analyze changes in immune cells in the central nervous system following HTLV‐1 infection, and the validation of up‐regulated genes in HTLV‐1‐associated B cells, such as TCL1A, was not conducted in this study.