Ipilimumab enhances the expression of activation markers on peripheral CD4 and CD8 T cells. A, Study design of treatment and sample collection. B, Immune snapshot of HLA-DR and ICOS expression on CD4 T cells in a representative patient. C and D, Changes in the expression of ICOS, (E and F) HLA-DR, (G and H) CTLA-4, and (I and J) PD-1 on CD4 (C, E, G, and I) and CD8 T cells (D, F, H, and J) were examined by flow cytometry analysis. Frequency of gated CD4 or CD8 T cells are shown for 24 patients at pre-treatment (V1), post-chemotherapy only (V2), and post-chemotherapy and ipilimumab (V3) timepoints. Statistical significance is represented by **** p ≤ 0.0001. Mean and SD are shown.