High–dimensional spectral cytometry of pretreatment PBMCs. (A) Immune profiling workflow. (B) The spectral cytometry flow panel including subset, lineage, exhaustion markers, and activation markers is shown with (A) designating markers not included in dimensionality reduction analysis. (C) Dimensionality reduction analysis of pretreatment PB T cells identified 12 unique T-cell populations. (D) T-cell populations separated by teclistamab responders and nonresponders.