Fig. 1

Effect of nivolumab treatment on levels of peripheral blood CD4⁺ cells, and their expression of immune mediators. Patient blood samples were collected prior to onset of nivolumab treatment and upon completion of treatment. Peripheral blood mononuclear cells (PBMC) were immunostained with antibodies to CD4, CD8, IFN-γ and Foxp3, and then analyzed by flow cytometry using the shown gating strategy (a). To quantitate the proportion of CD4⁺CD8⁻ cells (a and b), the analysis first gated on lymphoid cells. The CD4⁺CD8⁻ population was then gated on to determine the proportion of CD4⁺ cells that expressed IFN-γ (a and c) or Foxp3 (a and d). Each line color in panels b-d indicates the same patient across all panels