Baseline PBMC samples were analyzed by high-dimensional single cell profiling using mass cytometry. (A) Shown is phenograph clustering analysis performed after the exclusion of doublets, dead cells and CD19 cells and positive selection for CD45, CD3 and CD8. (B) PCA analysis of phenograph defined CD8+ clusters. (C) Stacked bar graph showing manually gated CD8+ naïve (CCR7+CD45ROneg), effector (CCR7negCD45ROneg), effector memory (CCR7negCD45RO+) and central memory (CCR7+CD45RO+) cell frequencies in individual patients. (D) Effector (CCR7negCD45ROneg) to naïve (CCR7+CD45ROneg) CD8+ T cell ratio at baseline among Progressors and Non-Progressors. Mann-Whitney tests were performed. *, p < 0.05. NE, not evaluable. NP, Non-Progressor. P, Progressor. EM, effector memory. CM, central memory.