Figure 5.

PD-1 blockade reduces Th2 phenotype of non-clonal bystander T lymphocytes in Sézary patients. The impact of in vitro PD-1 blockade on the Th1/Th2 phenotype of separate T cell subpopulation was evaluated by intracytoplasmic flow cytometry for IL-4 and IFN-γ. Percentage of IL-4 producing CD4⁺ T cells (a) and percentage of IL-4 producing CD8⁺ T cells (b) stimulated in the absence (blue dots) or presence (red dots) of 10 µg/mL nivolumab. Further gating demonstrates the change in percentage of IL-4 producers upon PD-1 blockade in non-clonal, bystander CD4⁺ T cells (c) versus clonal malignant T cells identified upon staining with T-cell receptor Vβ antibodies, specific for each individual patient, as described in Fig. 2 (d). (e–h) Distribution of IFN- γ producers amongst the same T cell fractions and stimulating conditions as described in (a-d). Data from five SS patients. Each dot represents data from one individual patient. The data obtained from the same patient are connected with dotted line.